[Federal Register Volume 76, Number 119 (Tuesday, June 21, 2011)]
[Rules and Regulations]
[Pages 36232-36279]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-14652]
[[Page 36231]]
Vol. 76
Tuesday,
No. 119
June 21, 2011
Part III
Nuclear Regulatory Commission
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10 CFR Part 50
American Society of Mechanical Engineers (ASME) Codes and New and
Revised ASME Code Cases; Final Rule
Federal Register / Vol. 76 , No. 119 / Tuesday, June 21, 2011 / Rules
and Regulations
[[Page 36232]]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
RIN 3150-AI35
[NRC-2008-0554]
American Society of Mechanical Engineers (ASME) Codes and New and
Revised ASME Code Cases
AGENCY: Nuclear Regulatory Commission.
ACTION: Final rule.
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SUMMARY: The NRC is amending its regulations to incorporate by
reference the 2005 Addenda (July 1, 2005) and 2006 Addenda (July 1,
2006) to the 2004 ASME Boiler and Pressure Vessel Code, Section III,
Division 1; 2007 ASME Boiler and Pressure Vessel Code, Section III,
Division 1, 2007 Edition (July 1, 2007), with 2008a Addenda (July 1,
2008); 2005 Addenda (July 1, 2005) and 2006 Addenda (July 1, 2006) to
the 2004 ASME Boiler and Pressure Vessel Code, Section XI, Division 1;
2007 ASME Boiler and Pressure Vessel Code, Section XI, Division 1, 2007
Edition (July 1, 2007), with 2008a Addenda (July 1, 2008); and 2005
Addenda, ASME OMa Code-2005 (approved July 8, 2005) and 2006 Addenda,
ASME OMb Code-2006 (approved July 6, 2006) to the 2004 ASME Code for
Operation and Maintenance of Nuclear Power Plants (OM Code). The NRC is
also incorporating by reference (with conditions on their use) ASME
Boiler and Pressure Vessel Code Case N-722-1, ``Additional Examinations
for PWR Pressure Retaining Welds in Class 1 Components Fabricated with
Alloy 600/82/182 Materials, Section XI, Division 1,'' Supplement 8,
ASME approval date: January 26, 2009, and ASME Boiler and Pressure
Vessel Code Case N-770-1, ``Alternative Examination Requirements and
Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt
Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material
With or Without Application of Listed Mitigation Activities, Section
XI, Division 1,'' ASME approval date: December 25, 2009.
DATES: This rule is effective July 21, 2011. The incorporation by
reference of certain publications listed in the rule is approved by the
Director of the Office of the Federal Register as of July 21, 2011.
ADDRESSES: You can access publicly available documents related to this
document using the following methods:
NRC's Public Document Room (PDR): The public may examine
and have copied for fee publicly available documents at the NRC's PDR,
Room O1-F21, One White Flint North, 11555 Rockville Pike, Rockville,
Maryland.
NRC's Agencywide Documents Access and Management System
(ADAMS): Publicly available documents created or received at the NRC
are available electronically at the NRC's Library at http://www.nrc.gov/reading-rm/adams.html. From this page, the public can gain
entry into ADAMS, which provides text and image files of NRC's public
documents. If you do not have access to ADAMS or if there are problems
in accessing the documents located in ADAMS, contact the NRC's PDR
reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to
[email protected].
Federal Rulemaking Web Site: Public comments and
supporting materials related to this final rule can be found at http://www.regulations.gov by searching on Docket ID: NRC-2008-0554.
FOR FURTHER INFORMATION CONTACT: L. Mark Padovan, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001, telephone 301-415-1423, e-mail [email protected].
SUPPLEMENTARY INFORMATION:
I. Background
II. Response to Public Comments
A. Overview of Public Comments
B. NRC Responses to Public Comments
III. Discussion of NRC Approval of New Edition and Addenda to the
Code, ASME Code Cases N-722-1 and N-770-1, and Other Changes to 10
CFR 50.55a
--Quality Standards, ASME Codes and Institute of Electrical and
Electronics Engineers (IEEE) Standards, and Alternatives
-- Applicant/Licensee-Proposed Alternatives to the Requirements
of 10 CFR 50.55a
-- Standards Approved for Incorporation by Reference
-- ASME B&PV Code, Section III
-- ASME B&PV Code, Section XI
-- ASME OM Code
-- Reactor Coolant Pressure Boundary, Quality Group B
Components, and Quality Group C Components
-- Inservice Testing Requirements
-- Inservice Inspection Requirements
-- Substitution of the Term ``Condition'' in 10 CFR 50.55a
IV. Paragraph-by-Paragraph Discussion
V. Generic Aging Lessons Learned Report
VI. Availability of Documents
VII. Voluntary Consensus Standards
VIII. Finding of No Significant Environmental Impact: Environmental
Assessment
IX. Paperwork Reduction Act Statement
Public Protection Notification
X. Regulatory and Backfit Analysis
XI. Regulatory Flexibility Certification
XII. Congressional Review Act
I. Background
The ASME develops and publishes the ASME Boiler and Pressure Vessel
Code (B&PV Code), which contains requirements for the design,
construction, and inservice inspection (ISI) of nuclear power plant
components; and the ASME OM Code, which contains requirements for
inservice testing (IST) of nuclear power plant components. The ASME
issues new editions of the ASME B&PV Code every 3 years and issues
addenda to the editions yearly, except in years when a new edition is
issued. Periodically, the ASME publishes new editions and addenda of
the ASME OM Code. The new editions and addenda typically revise
provisions of the Codes to broaden their applicability, add specific
elements to current provisions, delete specific provisions, and/or
clarify them to narrow the applicability of the provision. The
revisions to the editions and addenda of the Codes do not significantly
change Code philosophy or approach.
It has been the NRC's practice to establish requirements for the
design, construction, operation, ISI (examination) and IST of nuclear
power plants by approving the use of editions and addenda of the ASME
B&PV and OM Codes (ASME Codes) in Title 10 of the Code of Federal
Regulations (10 CFR), Section 50.55a. The NRC approves and/or mandates
the use of certain parts of editions and addenda of these ASME Codes in
10 CFR 50.55a through the rulemaking process of ``incorporation by
reference.'' Upon incorporation by reference of the ASME Codes into 10
CFR 50.55a, the provisions of the ASME Codes are legally-binding NRC
requirements as delineated in 10 CFR 50.55a, and subject to the
conditions on certain of the ASME Codes' provisions which are set forth
in 10 CFR 50.55a. The editions and addenda of the ASME B&PV and OM
Codes were last incorporated by reference into the regulations in a
final rule dated September 10, 2008 (73 FR 52730), as corrected on
October 2, 2008 (73 FR 57235), incorporating Section III of the 2004
Edition of the ASME B&PV Code, Section XI of the 2004 Edition of the
ASME B&PV Code, and the 2004 Edition of the ASME OM Code, subject to
NRC conditions.
The ASME Codes are consensus standards developed by participants
with broad and varied interests (including the NRC and licensees of
nuclear power plants). The ASME's adoption of new editions of and
[[Page 36233]]
addenda to the ASME Codes does not mean that there is unanimity on
every provision in the ASME Codes. There may be disagreement among the
technical experts, including NRC representatives on the ASME Code
committees and subcommittees, regarding the acceptability or
desirability of a particular Code provision included in an ASME-
approved code edition or addenda. If the NRC believes that there is a
significant technical or regulatory concern with a provision in an
ASME-approved code edition or addenda being considered for
incorporation by reference, then the NRC conditions the use of that
provision when it incorporates by reference that ASME Code edition or
addenda. In some cases, the condition increases the level of safety
afforded by the ASME code provision, or addresses a regulatory issue
not considered by the ASME. In other instances, where research data or
experience has shown that certain Code provisions are unnecessarily
conservative, the condition may provide that the Code provision need
not be complied with in some or all respects. The NRC's conditions are
included in 10 CFR 50.55a, typically in paragraph (b) of that
regulation. In an SRM dated September 10, 1999, the Commission
indicated that NRC rulemakings adopting (incorporating by reference) a
voluntary consensus standard must identify and justify each part of the
standard which is not adopted. For this rulemaking, the provisions of
the 2005 Addenda through 2008 Addenda of Section III, Division 1, and
the 2005 Addenda through 2008 Addenda of Section XI, Division 1, of the
ASME B&PV Code; and the 2005 Addenda and 2006 Addenda of the ASME OM
Code that the NRC is not adopting, or partially adopting, are
previously identified in Section III of this statement of
considerations, and in the regulatory and backfit analysis for this
rulemaking. The provisions of the ASME B&PV Code, OM Code, and Code
Cases N-722-1 and N-770-1 that the NRC finds to be conditionally
acceptable, along with the conditions under which they may be applied,
are also identified in Section III of this statement of considerations
and the regulatory and backfit analysis for this rulemaking.
The ASME Codes are voluntary consensus standards, and the NRC's
incorporation by reference of these Codes is consistent with applicable
requirements of the National Technology Transfer and Advancement Act
(NTTAA). Additional discussion on NRC's compliance with the NTTAA is
set forth in Section VII of this document, Voluntary Consensus
Standards.
II. Response to Public Comments
A. Overview of Public Comments
The NRC published a proposed rule for public comments in the
Federal Register on May 4, 2010 (75 FR 24324). The public comment
period for the proposed rule closed on July 19, 2010. The NRC received
22 letters and e-mails from the following commenters (listed in order
of receipt), providing about 454 comments on the proposed rule:
1. South Carolina Electric and Gas Company
2. Private citizen, Charles Wirtz
3. Private citizen, Gerry C. Slagis
4. Duke Energy
5. Electric Power Research Institute
6. Nextera Energy
7. IHI Southwest Technologies
8. Private citizen, Gary G. Elder
9. Performance Demonstration Initiative
10. Exelon Corporation
11. American Society of Mechanical Engineers
11a. American Society of Mechanical Engineers
12. Westinghouse
13. U.S. Department of Energy
14. Westinghouse
15. Progress Energy
16. PWR Owners Group
17. Nuclear Energy Institute
18. Entergy Operations, Inc. and Entergy Nuclear Operations, Inc.
19. Tennessee Valley Authority
20. Exelon Corporation
21. Dominion Resources Services, Inc.
22. Strategic Teaming and Resource Sharing (STARS)
The number assigned to each commenter is used to identify the
sponsor of the comment in the NRC's comment summary in Part B, ``NRC
Responses to Public Comments,'' of this document. Most of these
comments pertained to the following:
Suggested revising or rewording conditions to make them
more clear.
Supported incorporation of Code Case N-770 or N-770-1 into
10 CFR 50.55a.
Supported the proposed changes to add or remove
conditions.
Opposed proposed conditions.
Supplied additional information for NRC consideration.
Proposed rewriting/renumbering of paragraphs.
Asked questions or requested information from the NRC.
Due to the large number of comments received and the length of the
NRC's responses, this statement of considerations (SOC) addresses: (i)
Responses to the three questions raised by the NRC in the proposed
rule; (ii) comments resulting in changes to the proposed regulations;
and (iii) comments raising important issues of interest to stakeholders
but which the NRC declined to adopt. A discussion of all comments and
the NRC responses is available electronically at the NRC's Library,
ADAMS Accession No. ML110280240.
B. NRC Responses to Public Comments
Responses to Specific Requests for Comments
The NRC requested comments on three NRC questions associated with
its implementing 10 CFR 50.55a rulemaking process improvements to make
incorporating by reference ASME B&PV Code editions and addenda into 10
CFR 50.55a more predictable and consistent:
NRC Question 1. What should the scope of the ASME B&PV Code edition
and addenda rulemaking be (i.e., how many editions and addenda should
be compiled into a single rulemaking)?
Comment: One commenter stated that the NRC should address every
other edition of the ASME Code in subsequent rulemakings (begin
rulemaking once every 4 years) as the NRC's current 2-year rulemaking
cycle is ambitious, and previous rulemakings have not occurred on this
schedule. Three commenters indicated that starting with the 2013
Edition, editions of these Code sections will be published every 2
years (without addenda), and that future rulemakings should occur on a
2-year schedule, starting with the 2013 Edition of these Codes. [4-2,
11a-1; 14-1a; 19-1]
NRC Response: The NRC has decided that future 10 CFR 50.55a
rulemakings should incorporate only one later edition of the B&PV and
OM Codes at a time, starting with the 2013 Editions of the ASME B&PV
Code and the ASME OM Code.
NRC Question 2. What should the frequency of ASME B&PV Code edition
and addenda rulemaking be (i.e., how often should the NRC incorporate
by reference Code editions and addenda into 10 CFR 50.55a)?
Comment: The regulation currently requires compliance with the
latest ASME Section XI Code incorporated by reference in 10 CFR 50.55a
just 12 months prior to the start date of subsequent inspection
interval. A 4-year publication schedule for 10 CFR 50.55a final rules
would be beneficial for the following reasons:
a. This schedule would not be overly burdensome for the NRC, and
this may allow for a more predictable process and publication schedule
for 10 CFR 50.55a. A 4-year publication schedule would allow for more
licensees to use the same
[[Page 36234]]
Code of Record for multiple units at each site. This is particularly
true for those sites where multiple units were completed within 4 years
of the first unit. Use of a common Code of Record at each plant reduces
administrative burden for licensees and reduces the risks associated
with having to apply different Code requirements simultaneously at the
same plant This recommendation would also benefit the NRC because fewer
licensees would request relief to allow the use of a common Code of
Record. [4-2]
NRC Response: The NRC disagrees that a 4-year publication schedule
to incorporate ASME B&PV Code edition and addenda into 10 CFR 50.55a is
necessary for a more predictable process. The NRC performed a Lean Six
Sigma review of its 10 CFR 50.55a rulemaking process and implemented
improvements to make this rulemaking process more consistent and
predictable. The NRC now believes that it can consistently and
predictably publish 10 CFR 50.55a rulemakings on a 2-year interval.
The NRC agrees in principal that a 4-year review cycle could
possibly reduce the number of requests for relief when licensees use a
common code of record for multiple units at a site, and that it is less
of an administrative burden to have a common code of record at multiple
unit sites. However, reducing the number of requests would depend on
the timing of when a particular plant was required to update its
inservice inspection (ISI) program in accordance with Sec.
50.55a(g)(4). The option of using a common code of record at multiple
units is still available through the use of an alternative in
accordance with Sec. 50.55a(a)(3), and the NRC has approved the use of
alternatives many times in the past for this purpose.
Comment: As indicated in the draft rule, NRC rulemaking activities
are currently on a 2-year cycle. In order for each rulemaking to
incorporate by reference the latest published ASME Code editions, this
cycle should be maintained and the next NRC new rulemaking would have
to begin immediately upon publication of this proposed rule as a final
10 CFR 50.55a rule. [11a-1, 14-1b]
NRC Response: The NRC agrees that future 10 CFR 50.55a rulemakings
should occur on a 2-year schedule, starting with the 2013 Editions of
the ASME B&PV Code and the ASME OM Code. However, the NRC disagrees
that it should begin the next NRC rulemaking upon publication of this
final 10 CFR 50.55a rule. In order to assure that these rulemakings
occur consistently and predictably, the NRC is initiating a pilot
program to begin the next rulemaking when the camera-ready version of
the 2011 Addenda to the 2010 Edition of Sections III and XI of the ASME
B&PV Code becomes available. This start date is expected to be about 4
months earlier than the ASME's July 2011 publishing date, and should
contribute towards assuring that the NRC is able to publish the
rulemaking on a 2-year interval (from ASME's July publication date).
NRC Question 3. In what ways should the NRC communicate the scope,
schedule for publishing the rulemakings in the Federal Register, and
status of 10 CFR 50.55a rulemakings to external users?
Comment: Four commenters stated that the industry would benefit
from a predictable publication schedule for final 10 CFR 50.55a rules,
regardless of the frequency of subsequent rulemakings. One of these
commenters also indicated that, as an alternative, the NRC could
consider one of the following options to establishing a predictable
publication schedule:
10 CFR 50.55a could be amended to allow the use of a
limited number of Code editions that have been incorporated by
reference in 10 CFR 50.55a, instead of only the latest, provided all
applicable conditions are met when using the chosen Code edition.
10 CFR 50.55a could be amended to require that licensees
update their programs to comply with the latest Code of Record
incorporated by reference into 10 CFR 50.55a no more than 36 months
prior to the start of the subsequent 120-month inspection interval. [4-
2, 11a-1, 14-1c, 19-1]
NRC Response: The NRC acknowledges the industry's representation
that it would benefit from a predictable publication schedule for final
10 CFR 50.55a rules. As discussed, the NRC now believes that it can
consistently and predictably publish 10 CFR 50.55a rulemakings on a 2-
year interval. Thus, the NRC need not consider at this time the
alternative options presented by one of the commenters.
Comment: If the NRC believes that a predictable schedule for
publication of final 10 CFR 50.55a rules cannot be accomplished, the
NRC may want to consider whether the provisions in 10 CFR
50.55a(f)(4)(ii) and (g)(4)(ii) should be amended to allow Owners/
Licensees to update their programs to comply with the latest edition
and addenda of the Code incorporated by reference as much as 24 months
before the start of a subsequent 120 month interval. [11-1]
NRC Response: The NRC believes it can publish 10 CFR 50.55a
rulemakings on a predictable schedule as a result of implementing
rulemaking process improvements. Therefore, the NRC need not consider
the commenter's proposal at this time.
Re-Designating 10 CFR 50.55a Paragraphs
The NRC proposed that several paragraphs under 10 CFR 50.55a(b)(2)
be removed, which would cause gaps in the numbering between the
remaining paragraphs. To address the creation of these gaps, the NRC
proposed to re-designate (renumber) the remaining paragraphs under 10
CFR 50.55a(b)(2). These proposed re-designations are outlined in Table
1 of this document.
Comment: The proposed renumbering of paragraphs should not be
adopted. Renumbering all of the paragraphs, while helping to reduce the
number of pages in the rulemaking, does not consider the effort it will
take for each end user to update their procedures to reflect the new
numbering sequence. Many implementing programs and procedures will
include references to the specific paragraph for implementation.
Renumbering them will cause many documents to be revised. Recommend
that this type of cleanup be considered under a total rewrite of 10 CFR
50.55a rather than doing it under this proposed rule. Suggest that
those paragraphs where conditions are removed be designated as
``reserved.'' [4-1, 4-11a, 11-2, 14-2, 19-1, 20-1]
NRC Response: The NRC acknowledges the comments representing that
the proposed renumbering of paragraphs under 10 CFR 50.55a(b)(2) will
require end users to expend resources to update their procedures to
reflect the new numbering sequence. Accordingly, the NRC did not
renumber these paragraphs under 10 CFR 50.55a(b)(2) in the final rule.
Where the NRC removed paragraphs in the final rule, those paragraphs
are designated as ``Reserved.'' To assist readers in understanding the
regulatory history of this final rule, Table 1 gives a cross-reference
of proposed, current and final regulation paragraph numbering.
[[Page 36235]]
Table 1--Cross Reference of Proposed, Current and Final Regulations
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Description of proposed
Proposed regulation Current regulation redesignations Final regulation
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Paragraph (b)(2)(i)............ Paragraph Redesignate paragraph Paragraph (b)(2)(ii).
(b)(2)(ii). (b)(2)(ii) as
paragraph (b)(2)(i).
Paragraph (b)(2)(ii)........... Paragraph Redesignate paragraph Paragraph (b)(2)(vi).
(b)(2)(vi). (b)(2)(vi) as
paragraph (b)(2)(ii).
Paragraph (b)(2)(iii).......... Paragraph Redesignate paragraph Paragraph (b)(2)(vii).
(b)(2)(vii). (b)(2)(vii) as
paragraph (b)(2)(iii).
Paragraph (b)(2)(iv)........... Paragraph Redesignate paragraph Paragraph (b)(2)(viii).
(b)(2)(viii). (b)(2)(viii) as
paragraph (b)(2)(iv).
Paragraph (b)(2)(v)............ Paragraph Redesignate paragraph Paragraph (b)(2)(ix).
(b)(2)(ix). (b)(2)(ix) as
paragraph (b)(2)(v).
Paragraph (b)(2)(vi)........... Paragraph Redesignate paragraph Paragraph (b)(2)(x).
(b)(2)(x). (b)(2)(x) as paragraph
(b)(2)(vi).
Paragraph (b)(2)(vii).......... Paragraph Redesignate paragraph Paragraph (b)(2)(xi).
(b)(2)(xi). (b)(2)(xi) as
paragraph (b)(2)(vii).
Paragraph (b)(2)(viii)......... Paragraph Redesignate paragraph Paragraph (b)(2)(xii).
(b)(2)(xii). (b)(2)(xii) as
paragraph (b)(2)(viii).
Paragraph (b)(2)(ix)........... Paragraph Redesignate paragraph Paragraph (b)(2)(xiii).
(b)(2)(xiii). (b)(2)(xiii) as
paragraph (b)(2)(ix).
Paragraph (b)(2)(x)............ Paragraph Redesignate paragraph Paragraph (b)(2)(xiv).
(b)(2)(xiv). (b)(2)(xiv) as
paragraph (b)(2)(x).
Paragraph (b)(2)(xi)........... Paragraph Redesignate paragraph Paragraph (b)(2)(xv).
(b)(2)(xv). (b)(2)(xv) as
paragraph (b)(2)(xi).
Paragraph (b)(2)(xii).......... Paragraph Redesignate paragraph Paragraph (b)(2)(xvi).
(b)(2)(xvi). (b)(2)(xvi) as
paragraph (b)(2)(xii).
Paragraph (b)(2)(xiii)......... Paragraph Redesignate paragraph Paragraph (b)(2)(xvii).
(b)(2)(xvii). (b)(2)(xvii) as
paragraph (b)(2)(xiii).
Paragraph (b)(2)(xiv)(A)....... Paragraph Redesignate paragraph Paragraph (b)(2)(xviii)(A).
(b)(2)(xviii)(A). (b)(2)(xviii)(A) as
paragraph
(b)(2)(xiv)(A).
Paragraph (b)(2)(xiv)(B)....... Paragraph Redesignate paragraph Paragraph (b)(2)(xviii)(B).
(b)(2)(xviii)(B). (b)(2)(xviii)(B) as
paragraph
(b)(2)(xiv)(B).
Paragraph (b)(2)(xiv)(C)....... Paragraph Redesignate paragraph Paragraph (b)(2)(xviii)(C).
(b)(2)(xviii)(C). (b)(2)(xviii)(C) as
paragraph
(b)(2)(xiv)(C).
Paragraph (b)(2)(xv)........... Paragraph Redesignate paragraph Paragraph (b)(2)(xix).
(b)(2)(xix). (b)(2)(xix) as
paragraph (b)(2)(xv).
Paragraph (b)(2)(xvi).......... Paragraph Redesignate paragraph Paragraph (b)(2)(xx).
(b)(2)(xx). (b)(2)(xx) as
paragraph (b)(2)(xvi).
Paragraph (b)(2)(xvii)......... Paragraph Redesignate paragraph Paragraph (b)(2)(xxi).
(b)(2)(xxi). (b)(2)(xxi) as
paragraph (b)(2)(xvii).
Paragraph (b)(2)(xviii)........ Paragraph Redesignate paragraph Paragraph (b)(2)(xxii).
(b)(2)(xxii). (b)(2)(xxii) as
paragraph
(b)(2)(xviii).
Paragraph (b)(2)(xix).......... Paragraph Redesignate paragraph Paragraph (b)(2)(xxiii).
(b)(2)(xxiii). (b)(2)(xxiii) as
paragraph (b)(2)(xix).
Paragraph (b)(2)(xx)........... Paragraph Redesignate paragraph Paragraph (b)(2)(xxiv).
(b)(2)(xxiv). (b)(2)(xxiv) as
paragraph (b)(2)(xx).
Paragraph (b)(2)(xxi).......... Paragraph Redesignate paragraph Paragraph (b)(2)(xxv).
(b)(2)(xxv). (b)(2)(xxv) as
paragraph (b)(2)(xxi).
Paragraph (b)(2)(xxii)......... Paragraph Redesignate paragraph Paragraph (b)(2)(xxvi).
(b)(2)(xxvi). (b)(2)(xxvi) as
paragraph (b)(2)(xxii).
Paragraph (b)(2)(xxiii)........ Paragraph Redesignate paragraph Paragraph (b)(2)(xxvii).
(b)(2)(xxvii). (b)(2)(xxvii) as
paragraph
(b)(2)(xxiii).
Paragraph (b)(2)(xxiv)......... NA................ New Paragraph.......... Paragraph (b)(2)(xxviii).
Paragraph (b)(2)(xxv).......... NA................ New Paragraph.......... Eliminated.
Paragraph (b)(2)(xxvi)......... NA................ New Paragraph.......... Paragraph (b)(2)(xxix).
----------------------------------------------------------------------------------------------------------------
Significant Public Comments on the Proposed Rule
A summary of the significant comments, and the NRC's responses to
those comments for each 10 CFR 50.55a section or paragraph are set
forth in this document. A more comprehensive summary of the comments
and the NRC responses are set forth in the NRC's Analysis of Public
Comments document (ADAMS Accession No. ML110280240).
10 CFR 50.55a(b)(1)(iii) Seismic Design of Piping
Comment: The NRC received comments from a number of external
stakeholders that stated the proposed condition in Sec.
50.55a(b)(1)(A) should be deleted. The comments' bases for deleting the
proposed condition included the results of extensive research efforts
on ferritic steels operating at high temperature. The results of this
research were intended to provide sufficient bases to eliminate the
NRC's concern on the B2' stress indices for Class 1 elbows
and tees, on which the proposed condition) would have centered. [11-6b;
14-6b; 19-1]
NRC Response: Based on the NRC's review of the information provided
in the public comment, the NRC is not including the proposed condition
in Sec. 50.55a(b)(1)(A) on the B2' stress index for Class 1
elbows and tees in this final rule. The information presented by the
commenters adequately absolves the NRC's previously held concerns on
the use of these stress indices in the seismic design of Class 1
piping.
[[Page 36236]]
Comment: A minor modification to the proposed condition in Sec.
50.55a(b)(1)(iii)(B should be adopted to provide specificity on how the
condition should be applied. [14-6c]
NRC Response: The NRC agrees with the comment and the final rule
language includes the modification suggested by the comment. The NRC
agrees with the comment given that the modification eliminates
potential ambiguity by clearly articulating when the NRC's condition in
Sec. 50.55a(b)(1)(iii)(A) of the final rule language applies, with
respect to the use of the provisions of Subarticle NB-3200 of the ASME
Code.
Comment: The comments received on the proposed addition of the
condition 10 CFR 50.55a(b)(1)(iii)(C) pertained to the Do/t
limitation for the seismic design of piping. The scope of the proposed
condition in Sec. 50.55a(b)(1)(iii)(e) should be limited based on the
fact that the ASME Code inherently captures the proposed condition in
many instances in its current revision. [11-6d; 14-6d; 19-1]
NRC Response: The NRC agrees with the comments based on the fact
that the Do/t limitation is apparent throughout a majority
of the affected ASME Code sections. In the final rule, paragraph
(b)(1)(iii)(C) is modified to limit the scope of the proposed condition
to those portions of the ASME Code which do not provide the inherent
limitation on maintaining Do/t to a value of less than 40.
10 CFR 50.55a(b)(1)(vii) Capacity Certification and Demonstration of
Function of Incompressible-Fluid Pressure-Relief Valves
Comment: The NRC should reconsider its position to prohibit the use
of paragraph NB-7742. The commenter pointed out that NB-7742 addresses
test pressures that will exceed the test facility limits and reduces
the number of functional tests for specific valve designs. With
advances in technology, specialty valves were being developed that
would be a specific size, operate at a specific set pressure, and have
a required capacity. When only one such valve is installed in a nuclear
power plant, the manufacturer would have to build at least two
additional production valves so three valves could be tested per NB-
7732.2, and/or a multi-million dollar test facility would have to be
built that had the required test pressure capability. Since NB-7732.2
covers a range of conditions/applications for valve testing, the need
to address specialty valves that did not have a range in size and set
pressure, or had minimal range became evident. NB-7742(a)(1) and NB-
7742(a)(2) were added to address these applications. Manufacturing
unnecessary production valves and building new test facilities are not
economical options for the nuclear power industry. Therefore, the
commenter requested that the NRC reconsider its position to prohibit
the use of paragraph NB-7742. [14-8]
NRC Response: Upon reconsideration, the NRC agrees in general with
the comment that NB-7742 provides an acceptable methodology to test
incompressible-fluid, pressure-relief valves that will exceed the test
facility limits and addresses reducing the number of functional tests
for specific valve designs. The NRC has identified no issues with
performing tests at less than the highest value of the set-pressure
range for incompressible-fluid, pressure-relief valves and finds these
new requirements for Class 2 and 3 components acceptable as described
in paragraphs NC-7742 and ND-7742. However, the NRC has identified
words that were inadvertently left out of the Code during final
printing of paragraph NB-7742 for Class 1 components. The parallel
structure of the counterpart paragraphs (NC-7742 and ND-7742) reveal
that the words ``for the design and the maximum set pressure'' are
missing for paragraph NB-7742(a)(2). Without these words, paragraph NB-
7742(a)(2) is confusing, illogical, and could lead to a non-
conservative interpretation of the required test pressure for the new
Class 1 incompressible-fluid, pressure-relief valve designs. For these
reasons, paragraph (b)(1)(vii) of the final rule reflects a change to
include a condition allowing use of paragraph NB-7742 when the
corrected language intended by the Code is used.
10 CFR 50.55a(b)(2)(viii) Examination of Concrete Containments
(Proposed Rule Paragraph (b)(2)(iv))
Comment: Proposed rule paragraphs (b)(2)(iv)(B), (b)(2)(iv)(C),
(b)(2)(iv)(D)(1), and (b)(2)(iv)(D)(2) should be deleted since they are
not mandated by the introductory text of paragraph (b)(2)(iv). [20-4]
NRC Response: The NRC disagrees with the comment. The proposed rule
inadvertently removed the language in the introductory text of
paragraph (b)(2)(iv) that mandates the conditions in the mentioned
paragraphs. Final rule paragraph 10 CFR 50.55a(b)(2)(viii) added back
the removed language in the introductory text to correct this
unintended administrative error.
10 CFR 50.55a(b)(2)(ix) Examination of Metal Containments and the
Liners of Concrete Containments (Proposed Rule Paragraph (b)(2)(v))
Comment: The first part of the condition in the proposed rule
paragraph (b)(2)(v)(A) should not be applied to the 2006 through the
2008 Addenda, which incorporated requirements into IWE-2420(c) for
evaluating the acceptability of inaccessible areas when conditions
existed in accessible areas that could indicate the presence or result
in degradation to such inaccessible areas. Only the second part of the
condition requiring specific information relative to inaccessible areas
be submitted in the ISI Summary Report should apply to these addenda.
[11-15b; 14-15b; 19-1]
NRC Response: The NRC agrees with the comment since the first part
of the condition in proposed rule paragraph (b)(2)(v)(A) has been
incorporated into the 2006 Addenda through 2008 Addenda of the Code. As
a result of the comment, in final rule paragraph (b)(2)(ix)(A), the NRC
has restructured the condition into two separate paragraphs designated
(b)(2)(ix)(A)(1) and (b)(2)(ix)(A)(2) and revised the introductory text
such that the condition in paragraph (b)(2)(ix)(A)(1) that addresses
the requirement for the evaluation of inaccessible areas, is not
required to be applied to Subsection IWE, 2006 Addenda through the 2008
Addenda.
Comment: The new condition in the proposed rule paragraph
(b)(2)(v)(J), applicable to the use of IWE-5000 of the 2007 Edition
with the 2008 Addenda, should not apply to metallic shell and
penetration liners of Class CC components because these liners do not
serve a structural integrity function which, for Class CC containments,
is provided by the reinforced or post-tensioned concrete structure. The
containment pressure test requirements in IWL-5000 are sufficient to
ensure that the structural integrity of the Class CC component is
demonstrated following major modifications. [4-12c; 4-12f; 11-15c; 11-
15g; 14-15c; 14-15g; 19-1]
NRC Response: The NRC agrees with the basis of the comment that the
system pressure test requirements of IWL-5000 are adequate to
demonstrate both structural and leak-tight integrity of the repaired
Class CC containment pressure retaining components following a major
modification. Specifically, the requirements in IWL-5200 to perform a
containment pressure test at design basis accident pressure, and to
perform surface examinations of the repaired
[[Page 36237]]
area and specified additional/extended examinations and response
measurements, will demonstrate structural integrity of the repaired
Class CC concrete containment. The leakage test requirements in IWL-
5230 will demonstrate leak-tight integrity of the repaired area of the
metallic shell or penetration liner of Class CC containments. As a
result of the comment, the final rule paragraph (b)(2)(ix)(J) is
revised to indicate that the condition applies only to Class MC
pressure-retaining components and not to Class CC components.
Comment: The new condition in proposed rule paragraph (b)(2)(v)(J),
applicable to use of IWE-5000 of the 2007 Edition with the 2008 Addenda
for major containment modifications, allows for an alternative to an
Appendix J Type A test required by the condition following ``major''
modifications. However, performing a ``short-duration structural test''
as proposed would satisfy the condition in 10 CFR 50.55a, but would not
satisfy the requirements imposed by 10 CFR Part 50, Appendix J, Option
A. As a result, a ``short duration structural test'' cannot be
performed in lieu of a Type A Test, unless a licensee seeks an
exemption from the Appendix J test requirement, or 10 CFR part 50,
Appendix J, Option A is revised to address the proposed alternative
``short-duration structural test.'' [4-12b; 11-15i; 14-15i; 19-1]
NRC Response: The NRC agrees with the comment to the extent that
when a licensee is implementing Option A of 10 CFR part 50, Appendix J,
the alternative short duration structural test in the new condition in
proposed rule paragraph (b)(2)(v)(J) cannot be performed in lieu of the
Type A test required by the condition without seeking an exemption. The
NRC's agreement is based on the fact that an inconsistency would exist
between the requirement in the proposed rule paragraph (b)(2)(v)(J) and
the existing requirements under Special Testing Requirements in
paragraph IV.A of 10 CFR part 50, Appendix J, Option A. This
inconsistency would exist due to the fact that the current requirements
in Appendix J, Option A, would require a Type A test following a major
containment modification, while the proposed requirement would also
allow an alternative ``short duration structural test.'' The latter
cannot be performed in lieu of a Type A test, thus leading to an
inconsistency which could only be reconciled by an exemption. Paragraph
IV.A of 10 CFR part 50, Appendix J, Option A does not specify any
alternative structural test because the Type A test would demonstrate
both structural and leak tight integrity of the repaired containment.
The NRC disagrees with the comment, in part, given that for the
vast majority of licensees implementing Option B of 10 CFR part 50,
Appendix J, the argument could be made that containment modifications
are implemented under the Inservice Inspection Program in accordance
with ASME Section XI, Subsection IWE (for Class MC containments)
pursuant to 10 CFR 50.55a(g)(4). Therefore, it could be argued that the
system pressure testing requirements in IWE-5000 apply following
containment modifications and not those in paragraph IV.A of 10 CFR
part 50, Appendix J, Option A. Prior to the 2007 Edition of Section XI
of the ASME B&PV Code, Article IWE-5000 referenced paragraph IV.A of 10
CFR part 50, Appendix J, Option A, for the leakage test requirements
following containment modifications. By referencing the Appendix J,
Option A, requirements, Article IWE-5000 indirectly required a Type A
test to be performed following a major containment modification. Since
the Type A test requires pressurization of the entire containment to
the design basis accident pressure (Pa), it would provide a
verification of both the leakage integrity and structural integrity of
repaired containment. However, Article IWE-5000, as modified in the
2007 Edition and later addenda, provides a licensee the option of
performing only a local bubble test of the brazed joints and welds
affected by the repair even for major modifications. This provides a
verification of local leak-tightness of the repaired area, but does not
provide a verification of global structural integrity of the repaired
structure, and hence, the need for the new condition to perform a Type
A test following a major modification.
Based on this discussion, the NRC has determined that the new
condition in the final rule paragraph (b)(2)(ix)(J) only addresses the
deficiency identified in Article IWE-5000, and does not include the
provisions for an alternate short-duration structural test in the new
condition.
Comment: The actions specified in (b)(2)(v)(J)(1), (b)(2)(v)(J)(2)
and (b)(2)(v)(J)(3), as part of the alternate short duration structural
test, of the new condition in the proposed rule paragraph (b)(2)(v)(J),
applicable to the use of IWE-5000 of the 2007 Edition with the 2008
Addenda for Class MC components, should be modified as below.
The actions described in (b)(2)(v)(J)(1) should not apply
to the 2007 Edition with the 2008 Addenda of ASME Code, Section XI.
The condition in (b)(2)(v)(J)(2) should not apply because
IWE-5223 and IWE-5224 already provide adequate test requirements to
assure essentially zero leakage.
The actions described in (b)(2)(v)(J)(3) would prohibit
the conduct of the pressure test at a pressure less than Pa. The 10 CFR
part 50, Appendix J, Type A Test is permitted to be conducted at a test
pressure of at least 0.96Pa. [4-12d, 4-12e, 11-15d, 11-15e, 11-15f, 14-
15d, 14-15e, 14-15f, 19-1]
NRC Response: The NRC agrees with the comment because:
(i) The nondestructive examination of the repair welds specified in
paragraph (b)(2)(v)(J)(1) is typically required to be performed as part
of the repair process;
(ii) The provisions of IWE-5223 and IWE-5224 of the 2007 Edition
with the 2008 Addenda include the soap bubble or equivalent leakage
test specified in paragraph (b)(2)(v)(J)(2) and are adequate to assure
essentially zero leakage through the repair welds or joints; and
(iii) The action specified in paragraph (b)(2)(v)(J)(3) required
the entire containment to be pressurized to the peak calculated design
basis accident pressure (Pa) whereas a Type A test conducted
in accordance with ANSI/ANS 56.8 may be performed at a pressure between
0.96Pa and 1.1Pa.
However, the testing provisions of IWE-5223 and IWE-5224 of the
2007 Edition with the 2008 Addenda are not adequate to demonstrate
global structural integrity of the repaired Class MC containment, which
is essentially the deficiency that is sought to be addressed by the new
condition. In the context of IWE-5000, it is the Type A test that would
provide a verification of both structural and leak-tight integrity
following a major modification. As such, the NRC determined that the
new condition only addresses the deficiency in the provisions of
Article IWE-5000 and did not include the proposed alternate short-
duration structural test provision in the condition in the final rule.
Comment: The new condition in proposed rule paragraph (b)(2)(v)(J)
provides a general definition of ``major'' containment modifications as
repair/replacement activities such as replacing a large penetration,
cutting a large opening in the containment pressure boundary to replace
major equipment such as steam generators, reactor vessel heads,
pressurizers, or other similar modifications. This new condition does
[[Page 36238]]
not clearly define what constitutes a ``major'' modification or repair/
replacement activity for containment structures and that the lack of a
clear definition will cause potential confusion and possible conflict
with requirements of 10 CFR part 50, Appendix J, paragraph IV.A. [4-
12a, 11-15h, 14-15h, 19-1]
NRC Response: The NRC disagrees with the comment. The proposed rule
paragraph (b)(2)(v)(J) provides a definition of a ``major''
modification, which is qualitative but based on citing specific
examples of repair/replacement activities that have typically been
performed extensively among operating power reactors historically and
have been consistently considered as major modifications by the NRC
staff as well as licensees. The NRC acknowledges that the definition
provided for ``major'' modification in the proposed rule is somewhat
more explicit than the language used in 10 CFR part 50, Appendix J,
Option A, paragraph IV.A, in that the cited paragraph IV.A simply uses
the term ``major modification'' without any explicit description, but
the intent is consistent. Based on this discussion, the NRC has
retained the qualitative definition of major modifications in the final
rule. No change was made to the final rule as a result of this comment.
10 CFR 50.55a(b)(2)(xi) (Proposed Rule Paragraph (b)(2)(vii))
Comment: Referencing later versions of Appendix VIII should be
delayed and replaced with a mandatory, industry wide, version and
implementation date. In a December public meeting with the one of the
commenters (PDI), the commenter clarified his comment as requesting the
NRC to delay by 18 months the date on which Appendix VIII of the 2007
Edition and 2008 Addenda becomes effective for purposes of updating
licensees' 10-year inservice inspection interval. The commenter
explained that an 18-month delay is necessary to avoid an undue burden
on those licensees who have only 12 months to update their inservice
inspection program for the next 10-year inservice inspection interval
(as is required under Sec. 50.55a). [9-1; 9-2; 10-1; 10-2; 20-2]
NRC Response: The NRC agrees with the comments that there may be an
undue burden on those licensees who have only 12 months to update their
inservice inspection program to comply with Appendix VIII for the next
10-year inservice inspection interval. Accordingly, the NRC is revising
the language of the final rule to provide at least 18 months for a
specified set of licensees to update and begin implementation of the
2007 Edition and 2008 Addenda versions of Appendix VIII in their next
inservice inspection interval. This set of licensees are those whose
next inservice inspection interval must begin to be implemented during
the period between 12 through 18 months after the effective date of the
final rule, and therefore would otherwise be required to implement the
2007 Edition and 2008 Addenda versions of Appendix VIII (providing them
less than 18 months to comply with the provisions of the 2007 Edition
and 2008 Addenda versions of Appendix VIII). For these licensees, the
final rule provides a delay of 6 months in the implementation of
Appendix VIII only (i.e., these licensees will still be required to
update and implement the inservice inspection program during the next
inspection interval without delay). Other licensees, whose next
inservice inspection interval commences more than 18 months after the
final date of the rule, will have sufficient time to develop their
programs for the next inservice inspection interval and are not
affected by this provision of the final rule.
The NRC disagrees with the portions of the comments requesting that
the NRC mandate the use of later versions of Appendix VIII for all
licensees. The comments did not provide a technical or regulatory
justification for imposing such a backfit (a uniform date of
implementation would be regarded as a backfit because it departs from
the current regulatory approach of a ten-year inservice inspection
program interval). In addition, the NRC notes that Sec.
50.55a(g)(4)(iv) currently allows licensees to voluntarily comply with
the inservice inspection requirements of more recent editions and
addenda which the NRC has approved (via incorporation by reference into
Sec. 50.55a). Accordingly, the NRC declines to adopt the proposal. No
change was made to the final rule as a result of this portion of the
comment.
Comment: The requirements for scanning from the austenitic side of
the weld should be revised to accommodate certain exceptions such as
austenitic welds with no austenitic sides or austenitic welds attached
to cast austenitic components. [20-3]
NRC Response: NRC agrees that paragraph (b)(2)(xv)(A)(2) should
address the case of an austenitic weld which has no austenitic base
material side. An austenitic weld with no austenitic sides cannot be
qualified from an austenitic side. However, qualification from the
austenitic side of the weld demonstrates a higher degree of proficiency
than from the ferritic side of the weld. Therefore, an existing ASME
Code, Section XI, Appendix VIII, Supplement 10, Qualification
Requirements for Dissimilar (DM) Metal Welds, qualification may be
expanded for austenitic welds with no austenitic sides. This expansion
of the Supplement 10 qualification would require implementing a
separate performance demonstration add-on to include samples where the
austenitic weld is flanked by ferritic base material. The NRC disagrees
that special consideration should be given to components with cast
austenitic material on one side because single-side examination of
austenitic welds attached to cast stainless steel components is outside
the scope of the current qualification program. For these reasons,
paragraph (b)(2)(xv)(A)(2) in the final rule is revised to include an
add-on qualification for austenitic welds with no austenitic side to an
existing Supplement 10 qualification.
10 CFR 50.55a(b)(2)(xii) (Proposed Rule Paragraph (b)(2)(viii))
Comment: The condition on Appendix VIII single-side ferritic vessel
and piping and stainless steel piping examinations was addressed in the
2005 Addenda of ASME Code and should be removed. [11-17; 14-17a; 19-1]
NRC Response: The NRC agrees that the condition should not apply to
the 2007 Edition and 2008 Addenda because the condition was fully
addressed in the 2007 Edition of Section XI. However, the condition is
necessary through the 2006 Addenda because of changes within referenced
Supplements 5 and 7 in I-3000. For these reasons, paragraph (b)(2)(xvi)
is revised in this final rule to remove the condition from the 2007
Edition and 2008 Addenda but retains the condition through the 2006
Addenda.
10 CFR 50.55a(b)(2)(xiv)(C) (Proposed Rule Paragraph (b)(2)(x))
Comment: 10 CFR 50.55a(b)(2)(xiv)(C) should be revised to read:
``When applying editions and addenda prior to the 2005 Addenda of
Section Xl licensees qualifying visual examination personnel for VT-3
visual examination under paragraph IWA-2317 of Section Xl.'' The basis
for this recommendation is that IWA-2317 of the 2004 Edition does not
contain the requirements to demonstrate the proficiency of the training
by administering an initial qualification examination and administering
subsequent examinations on a 3-year interval. [20-5]
NRC Response: The NRC agrees with the commenter that the 2004
Edition
[[Page 36239]]
and earlier editions and addenda do not contain the requirements to
demonstrate the proficiency of the training and the commenter's
proposed wording is clearer. Paragraph (b)(2)(xviii)(C) of the final
rule has been revised to reflect the commenter's proposed wording.
10 CFR 50.55a(b)(2)(xv) (Proposed Rule Paragraph (b)(2)(xi))
Comment: Substitution of ultrasonic (UT) examinations performed in
accordance with Section XI, Appendix VIII for radiographic (RT)
examinations should be acceptable for repairs. ASME Code has already
approved three Code Cases for UT in lieu of RT and is in the process of
approving a fourth Code Case. [4-16; 7-1; 11-20b; 14-20; 19-1]
NRC Response: The NRC disagrees with the comment. Section III RT
examinations are for verifying the soundness of the full weld volume.
In Section XI, some welds do not have defined examination volumes, and
for the welds having defined examination volumes, only portions of the
volume are examined. Appendix VIII qualifications are demonstrated on
the weld volume defined in Section XI; the qualifications are tailored
for detection and sizing cracks propagating from the inner vessel or
pipe surfaces. The NRC's concerns with UT in lieu of RT are presented
in the statement of considerations published in the Federal Register on
October 27, 2006, (71 FR 62947) pertaining to Code Case N-659 which was
not approved for use in Regulatory Guide (RG) 1.193, Revision 2. The
NRC did not review the other two ASME approved code cases. The NRC will
review the fourth code case and associated documentation after ASME
approval. No change was made to the final rule as a result of this
comment.
Comment: The proposed rule implied UT was better suited for
detecting planar flaws associated with inservice degradation than
volumetric flaws, and not effective for volumetric flaws with large
openings. Further, few studies have been done to demonstrate
effectiveness of RT in a manner comparable to the way the effectiveness
of UT has been demonstrated via ASME, Section XI, Appendix VIII. [7-2]
NRC Response: The NRC agrees that few studies have been done to
demonstrate the effectiveness of RT in a manner comparable to the way
the effectiveness of UT has been demonstrated via ASME, Section XI,
Appendix VIII. In particular, there are limited studies that compare
the effectiveness of UT vs. RT on fabrication type flaws vs. service-
induced flaws for welds found in nuclear power plants. Until such time
as studies are complete, the NRC will remain silent on the ability of
UT to detect fabrication type (i.e., volumetric) flaws, as well as
comparing the abilities of UT and RT. No change was made to the final
rule as a result of this comment.
Comment: UT should be allowed for materials where it is as
effective, or more effective, than RT. The comment is specifically
targeted at UT on cast stainless steel components. [7-3]
NRC Response: Based on a recent study PNNL-19086, ``Replacement of
Radiography with Ultrasonics for the Nondestructive Inspection of
Welds--Evaluation of Technical Gaps--An Interim Report,'' (ADAMS
Accession No. ML101031254), the NRC believes that the effectiveness of
UT in lieu of RT has not been established. To address the NRC's
concerns, the NRC believes research must be conducted to:
Compare the flaw detection capabilities of UT and RT;
Assess parameters such as false call rates;
Assess qualification and acceptance standards;
Assess the effectiveness and reliability of UT and RT for
construction, preservice and inservice inspection;
Assess the interchangeability of UT and RT; and
Determine the state-of-the-art with regard to digital
radiography.
Therefore, no change was made to the final rule as a result of this
comment.
Comment: While UT requires more access and may require more weld
surface preparation area than RT, consideration should be given to
peripheral benefits of using UT associated with less work area
restrictions, no risk of radiation exposure, no RT source storage
issues, and reduced examination time. [7-4]
NRC Response: The NRC disagrees with this comment. While benefits
may exist, the NRC believes that examination and qualifications
concerns must be addressed first to establish effectiveness and
reliability of UT in lieu of RT. No change was made to the final rule
as a result of this comment.
Comment: UT systems needing to undergo a Section XI, Appendix VIII-
style demonstration and qualification program for construction flaws
prior to use is illogical for replacing RT systems that have not been
subjected to a similar demonstration and qualification program. [7-5]
NRC Response: The NRC disagrees with the comment. Based on study
PNNL-19086, the NRC believes that the effectiveness of UT in lieu of RT
has not been established. Accordingly, the NRC will be conducting
research as explained in the NRC response to comment 7-3. Though RT is
not subject to a rigorous qualification program at this time,
implementation of RT on new construction or repair welds in conjunction
with application of the qualified UT often performed for pre-service
inspections, provides a greater assurance of quality and safety than if
only one examination technique was implemented. Until such time as the
NRC has completed its evaluation of UT and RT for nuclear power plant
components, the NRC will not allow substitution of UT when RT is
prescribed for the examination. No change was made to the final rule as
a result of this comment.
Comment: V-path application with UT examination may not be
applicable for all metals where UT examinations are allowed. The NRC
should consider approving the substitution of UT for RT with specific
conditions or limitations, such as:
(1) UT may not be used in lieu of RT for examination of cast
stainless steel or austenitic stainless steels and nickel alloys where
only single-sided access is available;
(2) When UT is used in lieu of RT, the acceptance standards of ASME
Section XI IWA-3000 shall be used in lieu of the construction code
acceptance standards; and
(3) Encoded or automated UT shall be used to create a permanent
record which would allow multiple analysis reviews as well as document
the results for comparison with future examinations. [7-6]
NRC Response: The NRC believes that the effectiveness of UT in lieu
of RT has not been established. Industry studies have been initiated to
evaluate NRC concerns with UT in lieu of RT. The NRC will consider the
results from these studies in future reviews. Therefore, proposed
paragraph (b)(2)(xv) pertaining to IWA-4520(b)(2) and IWA-4521 is
adopted without change in final rule paragraph (b)(2)(xix). No change
was made to the final rule as a result of this comment.
Comment: With regard to paragraph (b)(2)(xv), clarify whether the
substitution of ASME Section V ultrasonic examination method by an
Appendix VIII ultrasonic examination method is allowed by the
provisions of IWA-2240 of the 1997 Addenda as specified in this
paragraph's condition. [20-6]
NRC Response: The NRC disagrees with the comment, because it is not
the NRC's regulatory responsibility to clarify the ASME Code. No change
was made to the final rule as a result of this comment.
[[Page 36240]]
10 CFR 50.55a(b)(2)(xvii)(B) (Proposed Rule Paragraph (b)(2)(xiii))
Comment: Consideration should be given to deleting this condition
entirely as it is inconsistent with the unconditional approval of Code
Case N-652-1 in NRC RG 1.147, Rev 15, which does not include Item B7.80
or any provisions for examination of CRD bolting. [2-2]
NRC Response: The NRC agrees that Item No. B7.80 was deleted in the
1995 Addenda of Section XI. The NRC also agrees that the existing
condition is inconsistent with the NRC unconditional approval of Code
Case N-652-1 which eliminates Item No. B7.80 requirements. The NRC also
believes that Examination Category B-G-2 contains examination
requirements for all Class 1 pressure retaining bolting 2 inches and
less in diameter to provide reasonable assurance of their structural
integrity. For these reasons the NRC agrees with the comment. Final
rule paragraph (b)(2)(xxi) reflects a change to eliminate the condition
that provisions of Table IWB-2500-1, Examination Category B-G-2, Item
B7.80, that are in the 1995 Edition are applicable only to reused
bolting when using the 1997 Addenda through the latest edition and
addenda incorporated by reference in paragraph (b)(2) of this section.
10 CFR 50.55a(b)(2)(xxiv) (Proposed Rule Paragraph (b)(2)(xx))
Comment: The NRC condition, which would place conditions on the use
of Equation (2) in A-4300(b)(1) of Nonmandatory Appendix A of Section
XI, should be removed because the condition would result in more
conservative crack growth rates to be computed when R-ratio (i.e.,
Kmin/Kmax) is negative. The basis for 1.12
Sf factor was established from lab data for R < 0 and
considers crack closure effects. [11-23; 14-23; 19-1]
NRC Response: The NRC disagrees with the comment. The NRC has
reviewed the laboratory test data upon which this provision was based,
and concludes that it is insufficient to firmly establish the Section
XI, Appendix A approach when the R-ratio is negative.
The test data reported in the 1977 ASME Pressure Vessels and Piping
Conference paper, ``High Stress Crack Growth--Part II, Predictive
Methodology Using a Crack Closure Model,'' which serves as the basis
for the ASME Code, Section XI, Appendix A approach, consists of only 10
test data points for -1.5 < R < 0, and one of those data points shows a
trend opposite of the others. Although this data was produced from
tests covering a limited R value range, it is used to support the
application of the ASME Code, Section XI, Appendix A approach for a
much wider range of R, (i.e., all R < 0).
Further, in ASME Code, Section XI, Appendix A applications, the
generic, lower-bound material property values from ASME Code, Section
II may be used. If the lower bound ASME Code, Section II generic flow
stress ([sigma]f) for a material is less than the material's
actual [sigma]f, the calculation in accordance with ASME
Code, Section XI, Appendix A for R < 0 will show that Kmax -
Kmin <= 1.12 [sigma]f [radic]([pi]a) and prompt a
wrongful reduction of [Delta]KI where full
[Delta]KI should be used. This potential non-conservatism in
the use of the ASME Code, Section XI, Appendix A approach, along with
the issues cited above regarding the available test data, calls into
question the generic applicability of the ASME Code, Section XI,
Appendix A approach.
For these reasons, the NRC disagrees with the comment. No change
was made to the final rule as a result of the comment.
10 CFR 50.55a(b)(2)(xxv) (Proposed Rule Paragraph (b)(2)(xxi))
Comment: Qualitative arguments based on a deterministic approach
stated the current provision in Table E-2 for a crack size up to 1 inch
deep is sufficient based on:
(1) Real flaw sizes in vessels are closer to a depth of
approximately 0.10 inch deep or less based on actual vessel inspection
data;
(2) Use of ASME Code, Section XI, Appendix VIII, and Electric Power
Research Institute (EPRI) Performance Demonstration Initiative (PDI)
provides continuous verification that the beltline region welds are
either free of defects larger than approximately 0.10 inch or that they
are documented and recorded, and;
(3) Additional conservatism exists in the use of a lower bound
reference toughness curve for prevention of crack initiation for these
reference flaws.
[11-24; 11-24; 16-17;16-18; 16-19; 16-20; 17-2; 17-3; 17-4; 17-5; 17-9;
17-11; 19-1; 20-8; 20-11; 20-12; 20-13; 21-2; 21-3; 21-4; 21-5; 21-6
and 21-7]
Quantitative results based on a probabilistic approach demonstrate
that the current Appendix E approach provides an appropriate
conservative methodology following an unanticipated transient. The
Pressurized Water Reactor Owners Group (PWROG) has provided a risk-
informed assessment of Appendix E, which indicated that by setting the
core damage frequency (CDF) to 1E-6, the resulting pressure versus (T-
RTNDT) curve bounds the corresponding Appendix E curve for
both the PWR unanticipated isothermal pressure events and the
pressurized cool-down events, where T is the reactor pressure vessel
(RPV) coolant temperature and RTNDT is the nil-ductility
reference temperature of the limiting RPV material. [16-21]
NRC Response: The commenter's qualitative arguments based on the
deterministic approach involve extensive discussions. However, the
bottom line is the same as for Comments 11 and 14. Hence, the NRC will
respond to only selective parts of the comments based on the
deterministic approach to clarify its position. This is appropriate
because the NRC's final position is not based on the qualitative,
deterministic fracture mechanics (FM) arguments, but on the
quantitative, probabilistic fracture mechanics (PFM) results provided
by the PWROG.
The NRC agrees with most of the qualitative arguments based on the
deterministic FM approach. However, the NRC's final position to accept
ASME Code, Section XI, Appendix E without the proposed conditions is
not because of these arguments, but rather because of the supporting
quantitative PFM results provided by the PWROG.
Although most of the qualitative arguments based on the
deterministic FM approach have merit, they can only demonstrate that
the probability of having a flaw close to 1/4T in size is very low.
They cannot rule out that such a large flaw could exist. This
observation is consistent with a key statement regarding a large flaw
in NUREG-1806, ``Technical Basis for Revision of the Pressurized
Thermal Shock (PTS) Screening Limit in the PTS Rule (10 CFR 50.61).''
NUREG-1806 states ``It should also be noted that the empirical data
used as the primary evidence to establish the distribution of embedded
weld flaws do not, and cannot, provide any information about the
maximum size a flaw can be.''
The final PTS rule (75 FR 13) published on January 4, 2010, is
based on a PFM analysis using a weld flaw distribution with a cutoff
flaw depth close to 1/4T of the RPV wall, indicating that although the
1/4T flaw has a low probability of existence it is prudent to still
consider it.
The FM analyses in both ASME Code, Section XI, Appendix G and ASME
Code, Section XI, Appendix E are based on postulated flaws using linear
elastic FM in a deterministic approach. It is appropriate to assume
different margins for these two types of analyses to
[[Page 36241]]
account for the very different occurrence frequencies of the two
events. However, it is too aggressive to change the fundamental flaw
size assumption simply based on different event frequencies. Further,
both appendices are for all RPVs, including the one with the worst
combination of transients (for the Appendix E analysis), largest
undetected flaw size, and worst degradation in fracture toughness.
Therefore, unless a PFM approach is used which accounts for a large
size flaw with its low probability, it is prudent that the fundamental
flaw size assumption remains the same in these two deterministic FM
analyses. The PWROG provided such a PFM approach in its response.
The PWROG performed a risk-informed assessment of Appendix E using
the Fracture Analysis of Vessels--Oak Ridge (FAVOR) Code; the same tool
used in the PFM analyses supporting the final PTS rule. Based on a
selected PWR and BWR RPV having the highest RTNDT of the
limiting RPV material and a typical beltline fluence model, the PWROG
generated a pressure versus (T-RTNDT) curve for each of the
two RPVs by setting the CDF to 1E-6. The analytical results showed that
the PWROG's PFM results bounds the corresponding Appendix E curve for
both the unanticipated isothermal pressure events and the pressurized
cool-down events. Since (1) the PFM methodology is consistent with the
PTS rule's underlying methodology, in which large flaws are considered
statistically, and (2) the resulting pressure versus (T-
RTNDT) curve bounds the corresponding curve based on the
current Appendix E approach, the NRC concludes that the current
Appendix E methodology, without the NRC's proposed condition, provides
an appropriate conservative methodology for evaluating RPV integrity
following an unanticipated transient that exceeds the operational
limits in PWR plant operating procedures.
For these reasons, the NRC agrees with the comment based on the PFM
analyses that the current ASME Code, Section XI, Appendix E analysis is
appropriate. The proposed conditions placed on the use of ASME Code,
Section XI, Appendix E in the proposed rule are, therefore, not
included in the final rule.
Comment: Section E-1200 is useful and conservative as is, and
prohibiting the use of Section E-1200 will ultimately result in added
utility burden or loss of generation because of the additional time
required to perform analysis under Section E-1300. It is estimated that
a Section E-1200 evaluation can be completed in hours while a Section
E-1300 evaluation may require days or weeks. Furthermore, use of a 1/4T
flaw size can produce unacceptable analytical results, even though
crack initiation has not occurred, thereby complicating the resolution
process following a fairly minor thermal transient or overpressure
event. [11-24, 14-24, 17-11, 19-1, 21-7]
NRC Response: The NRC agrees with this comment based on the PFM
Analysis provided by the PWROG. The final rule does not include the
condition of paragraph (b)(2)(xxv) from the proposed rule.
Comment: The NRC should reconsider the change specifying ``* * *
that Section E-1200 is not acceptable.'' The intent of Section E-1200
is to provide licensees a conservative and yet simple screening method
that can be used to immediately judge whether a reactor vessel can be
returned to service or whether a more in-depth analysis is needed prior
to returning the reactor vessel to service following an unanticipated
event. The evaluation procedures in Appendix E, Paragraphs E-1200 and
E-1300, provide adequate safety margins for evaluating reactor pressure
vessel integrity following an unanticipated event that results in
pressures and temperatures outside the limits established for normal
operation. Additionally, Appendix E is consistent with risk-informed
acceptance criteria for normal operating and unanticipated events.
Consequently, modifying Appendix E as proposed is unnecessary and
disallowing use of Section E-1200 will result in an undue hardship
without any compensating increase in safety. [20-7]
NRC Response: The NRC agrees with this comment based on the PFM
Analysis provided by the PWROG. The final rule does not include the
condition of paragraph (b)(2)(xxv) from the proposed rule.
10 CFR 50.55a(b)(2)(xxvi) (Proposed Rule Paragraph (b)(2)(xxii))
Comment: If the NRC intends to require that Risk-Informed ISI (RI-
ISI) Programs comply with RG 1.178, RG 1.200, and NRC Standard Review
Plan 3.9.8, then in lieu of the proposed condition in paragraph
(b)(2)(xxvi), the proposed condition should specify that use of
Nonmandatory Appendix R is acceptable, provided licensees comply with
these applicable RGs and the Standard Review Plan 3.9.8. [4-18; 11-25;
14-25; 19-1]
NRC Response: The NRC disagrees with the comment and believes that
RI-ISI programs developed in accordance with Nonmandatory Appendix R
should continue to be submitted as alternatives in accordance with 10
CFR 50.55a(a)(3). The NRC has not generically approved RI-ISI
application because the code-approved guidance to date has not
addressed inspection strategy for existing augmented and other
inspection programs such as intergranular stress corrosion cracking
(IGSCC), flow assisted corrosion (FAC), microbiological corrosion
(MIC), and pitting or provided system-level guidelines for change in
risk evaluation to ensure that the risk from individual system failures
will be kept small and dominant risk contributors will not be created.
Furthermore, allowing the use of Nonmandatory Appendix R without
requiring submittal of an alternative would allow plants being licensed
and constructed in accordance with 10 CFR part 52 to implement
Nonmandatory Appendix R. The NRC believes at this time that the use of
Nonmandatory Appendix R at plants licensed under 10 CFR part 52 plants
is something that requires additional review of plant specific
applications. For these reasons the NRC disagrees with the comment. No
change was made to the final rule as a result of the comment.
10 CFR 50.55a(b)(3)(v) Subsection ISTD. Article IWF-5000, ``Inservice
Inspection Requirements for Snubbers''
Comment: 10 CFR 50.55a(b)(3)(v) should be revised as follows for
clarification:
(v) Subsection ISTD. Article IWF-5000, ``Inservice Inspection
Requirements for Snubbers,'' of the ASME B&PV Code, Section XI, must be
used when performing inservice inspection examinations and tests of
snubbers at nuclear plants, except as modified in (A) and (B) below.
[11-27; 14-27a; 17-12; 19-1]
NRC Response: The NRC agrees that paragraph (b)(3)(v) should be
clarified, and revised it to include references to paragraphs
(b)(3)(v)(A) and (b)(3)(v)(B). The recommended change provides clarity
between the selection of paragraph (b)(3)(v)(A) or (b)(3)(v)(B). The
final rule is revised to add the suggested references.
10 CFR 50.55a(b)(3)(v)(A)
Comment: It is unclear whether the intent of paragraph (b)(3)(v) is
that, after licensees have updated their programs to comply with the
2006 Addenda and later editions and addenda of the ASME B&PV Code and
the equivalent endorsed edition and addenda of the ASME OM Code,
Subsection ISTD, preservice and inservice examinations need not be
performed using a VT-3 visual
[[Page 36242]]
examination method as described in IWA-2213. [14-27b; 17-13]
NRC Response: The NRC agrees with this comment to the extent that,
as described in paragraph (b)(3)(v)(A), VT-3 visual examination must be
used while using ASME OM Subsection ISTD in lieu of the requirements
for snubbers in the editions and addenda up to the 2005 Addenda of the
ASME Section XI, IWF-5200(a) and (b), and IWF-5300(a) and (b).
Paragraph (b)(3)(v)(B) states that licensees using the 2006 Addenda and
later editions of the ASME OM Code Subsection ISTD are not required to
use VT-3 visual examination, because in the ASME OM Code snubber (pin-
to-pin) visual examination VT-3 requirements have been replaced with
the Owner's defined visual examination. However, removing VT-3
requirements for snubbers does not remove VT-3 requirements of support
structure(s) and attachments as defined in IWF of ASME Section XI.
The proposed rulemaking would not change the intent of the current
paragraph (b)(3)(v). The proposed rulemaking would split paragraph
(b)(3)(v) into (b)(3)(v)(A) and (b)(3)(v)(B), because snubber inservice
examination and testing requirements have been deleted in the 2006
addenda and later Editions of ASME Section XI. Up to, and including,
the 2005 Addenda, both ASME Section XI and ASME OM Code contained
snubber examination and testing requirements. Now, in the 2006 Addenda,
the ASME OM Code is the only Code which contains the inservice
examination and testing requirements of snubbers. The paragraph
(b)(3)(v)(A) option is for licensees using ASME Section XI up to the
2005 Addenda, which is similar to the current paragraph (b)(3)(v). The
paragraph (b)(3)(v)(B) option is for the licensees using the 2006
Addenda or the later edition of ASME Section XI, where the licensee
will not find any snubber requirements in ASME Section XI; therefore,
the ASME OM Code must be used.
The intent of current paragraph (b)(3)(v) is based on the ASME
Section XI, IWF-5000 and ASME OM, Subsection ISTD requirements. The
ASME Section XI up to the 2005 Addenda does not clearly distinguish the
boundary between the support structure, attachments and the snubber.
The inservice examination of the support structure and attachments is
performed using VT-3 as required by Subsection IWF of Section XI, and
IWF-5000 requires that snubber examination must be performed using VT-3
visual examination as described in IWA-2213. Subsection ISTD of the
ASME OM Code does not address inspection of the support structure and
attachments. Therefore, to be consistent with the Section XI
requirements, VT-3 visual examination is required when using Subsection
ISTD of the OM Code in lieu of the IWF-5000 requirements of ASME
Section XI, up to the 2005 Addenda. The proposed VT-3 requirement is
consistent with the current requirement to ensure that an appropriate
visual examination method was used for integral and non-integral
snubber supports and attachments such as lugs, bolting, and clamps when
using ISTD of the ASME OM Code in lieu of the ASME Section XI, 2005
Addenda.
In the 2006 Addenda and later edition of ASME Section XI, the
inservice examination and testing requirements of snubbers have been
deleted, and a Figure IWF-1300-1(f) has been added to clarify the
boundary of a snubber (pin-to-pin) and its support structure and
attachments. Figure IWF-1300-1(f) defines that a snubber (pin-to-pin)
examination is excluded from Section XI, and the support structure and
attachments, etc. are still under the scope of ASME Section XI. ASME
Section XI, IWF-1220 in the 2006 Addenda and later edition states that
inservice examination and testing of snubbers are outside the Scope of
IWF, and can be found in the ASME OM Code. Subsection IWF requires that
the inservice examination of support structure and attachments are to
be performed using VT-3 visual examination, whereas the ASME OM Code
requires that snubber (pin-to-pin) visual examination is to be
performed using the Owner's qualified procedures and methods. However,
if licensees prefer, the VT-3 visual examination method still can be
used for snubber (pin-to-pin) inservice examination, while using ASME
OM Code requirements. No change was made to the final rule as a result
of this comment.
10 CFR 50.55a(b)(3)(v)(B)
Comment: The examination boundary for a snubber examination as
defined in ISTD is the snubber unit out to the pins that hold it in
place. Commenters request that the NRC clarify in the final rule
whether the pin-to-pin ISTD examination of the snubber unit should be a
VT-3, even though a VT-3 examination is a Section XI requirement. [14-
27c; 17-13]
NRC Response: The NRC clarifies that the licensees are required to
meet the snubber (pin-to-pin) visual examination requirements as
specified in the Subsection ISTD of the ASME OM Code when using the
2006 Addenda and later editions and addenda of Section XI of the ASME
B&PV Code, as defined in paragraph (b)(3)(v)(B). Subsection ISTD of the
ASME OM Code, 2006 Addenda and later editions requires that snubber
(pin-to-pin) visual examination is to be performed using the Owner's
qualified procedures and methods, whereas licensees must use VT-3 for
integral and non-integral structure and attachments as required by ASME
Section XI. However, licensees may use VT-3 visual examination method
for snubber (pin-to-pin) inservice examination, while using ASME OM
Code, 2006 Addenda and later editions.
When using the 2005 Addenda or earlier editions and addenda of the
ASME OM Code, Subsection ISTD in lieu of the ASME Section XI, IWF-5000
as defined in paragraph (b)(3)(v)(A), licensees must use VT-3 visual
examination for snubbers (pin-to-pin) and integral and non-integral
structure and attachments as required by ASME Section XI.
Inservice Testing
10 CFR 50.55a(f)(5)(iv)
Comment: The words ``and is not included in the revised inservice
test program as permitted by paragraph (f)(4) of this section'' seem to
imply that a licensee need not seek relief if the inservice test
program is revised to identify the impractical test requirement. If
this is the intent of these words, licensees may not need to submit
relief requests for IST Program impracticality if the IST Program is
updated. If this is not the intent of these words, then the phrase
``and is not included in the revised inservice test program as
permitted by paragraph (f)(4) of this section'' should be removed from
paragraph (f)(5)(iv). [4-22]
NRC Response: The NRC does not agree with the comment. The proposed
amendment states that where a pump or valve test requirement by the
code or addenda is determined to be impractical by the licensee and is
not included in the revised inservice test program, the basis for this
determination must be submitted for NRC review and approval not later
than 12 months after the expiration of the initial 120-month interval
of operation. Therefore, a licensee has to submit relief requests for
inservice testing (IST) Program impracticality if the IST Program is
updated. No change was made to the final rule as a result of this
comment.
[[Page 36243]]
Inservice Inspection
10 CFR 50.55a(g)(2), (g)(3)(i), (g)(3)(ii), (g)(4)(i) and (g)(4)(ii)
Comment: The introductory text and other applicable sections should
state that licensees use the provisions for examination and testing of
snubbers in Subsection ISTD of the ASME OM Code or the requirements in
plant Technical Specifications (TS). [1-1; 17-6]
NRC Response: The NRC does not agree with the commenter to include
the optional provision of TS requirements for inservice examination and
testing of snubbers along with Subsection ISTD of the ASME OM Code.
Paragraph (g) establishes the ISI requirements that licensees must
use when performing ISI of components (including supports).
Additionally, paragraph (g)(4)(iv) states that ISI of components
(including supports) may meet the requirements set forth in subsequent
editions to the ``Code of Record'' and addenda that are incorporated by
reference in 10 CFR 50.55a(b), subject to limitations and modifications
listed in 10 CFR 50.55a(b) and subject to NRC approval.
The requirements at 10 CFR 50.55a do not define any documents
beyond ``Code of Record'' to control the snubber inservice examination
and testing program. Licensees have the option to control the ASME
Code-required ISI and testing of snubbers through their TS or other
licensee-controlled documents (e.g. technical requirements manual,
etc.). For facilities using their TS to govern ISI and testing of
snubbers, paragraph (g)(5)(ii) requires that if a revised ISI program
for a facility conflicts with the TS, the licensee shall apply to the
NRC for amendment of the TS to conform the TS to the revised program.
Therefore, the regulation does not state the type of documents to be
used by the licensees to meet the snubber inservice examination and
testing requirements as specified in the ASME Code, but TS must meet
the ``Code of Record'' requirements. For a particular facility, the
snubber inservice examination and testing may be controlled by its TS,
including the applicable snubber inservice examination and testing
requirements as specified in the ASME Code. No change was made to the
final rule as a result of this comment.
10 CFR 50.55a(g)(5)(iii) and (g)(5)(iv)
Comment: The proposed rule adds extra burden on licensees to submit
relief requests within 12 months of examinations where code
requirements were determined to be impractical and the proposed rule
language would put paragraph (g)(5)(iii) in conflict with paragraph
(g)(5)(iv). [2-3; 4-25; 11-31a-g; 14-31; 17-7; 17-10; 18-1; 20-14; 21-
1; 22-1]
NRC Response: The NRC agrees with the comments that paragraph
(g)(5)(iii) would place an extra burden on the licensee by requiring
that requests for relief made in accordance with paragraph (g)(5)(iii)
must be submitted to the NRC no later than 12 months after the
examination has been attempted. This requirement could increase the
number of submittals licensees need to submit for code requirements
determined to be impractical. Rather than submitting one request for
relief at the end of the interval for all requirements determined to be
impractical throughout the 10-year interval as currently allowed,
licensees would be required to prepare a submittal within 12 months of
every examination that determined a requirement was impractical. This
could result in the licensee preparing numerous submittals for relief
requests where under the current rules only one submittal is required
at the end of the interval. This requirement is revised in this final
rule to align with paragraph (g)(5)(iv) to require submittal of these
requests no later than 12 months after the expiration of the initial or
subsequent 120-month inspection interval for which relief is sought.
Comment: Paragraph (g)(5) in general, and this proposed change to
paragraph (g)(5)(iii) in particular, could also have a direct impact on
examinations associated with welds and weld repairs performed during
the course of a repair/replacement activity. Based on the proposed
change to paragraph (g)(5)(iii), it could be argued that a relief
request does not have to be submitted until after performance of a weld
repair and alternative NDE or NDE with limited coverage. If the intent
is to exclude NDE associated with welds and weld repairs (i.e., repair/
replacement activities), then the proposed change to paragraph
(g)(5)(iii) should be revised to make this clarification. [17-8; 17-14;
18-2]
NRC Response: If a licensee proposes to use a different inspection
technique (e.g., UT vs. RT), an alternative must be submitted under the
provisions of 10 CFR 50.55a(a)(3), regardless of what amount of
coverage they would achieve with either technique. If the licensee has
knowledge of the fact that the inspection using the different
inspection technique will be limited, it is the NRC's expectation that
such information will be included as an integral part of the requested
alternative. The alternative that would be approved would be based on
the technique and the amount of coverage the licensee expects to
achieve. If the requested alternative is approved and the licensee
achieves less coverage using the alternative inspection technique than
that stipulated in the original alternative request, the licensee would
need to submit a request for relief based on 10 CFR 50.55a(g)(5). No
change was made to the final rule as a result of this comment.
Comment: The requirement to submit the relief request after the
examination has been attempted may in fact be a clarification of the
NRC's intent, but the requirement to submit the relief request within
12 months of the attempt is certainly not a clarification, it is a new
requirement. [2-3]
NRC Response: The NRC agrees that submitting the relief request
within 12 months of the attempted examination would be a new
requirement, which was not the NRC's intent. This paragraph is revised
in this final rule to align with paragraph (g)(5)(iv).
Comment: The words ``and is not included in the revised inservice
inspection program as permitted by paragraph (g)(4) of this section''
seem to imply that a licensee need not seek relief if the inservice
inspection program is revised to identify the impractical requirement.
If this is the intent of these words, licensees may not need to submit
relief requests for ISI Program impracticality if the ISI Program is
updated. If this is not the intent of these words, then the phrase
``and is not included in the revised inservice inspection program as
permitted by paragraph (g)(4) of this section'' should be removed from
10 CFR 50.55a(g)(5)(iv). [4-26]
NRC Response: The NRC agrees the phrase, ``and is not included in
the revised inservice inspection program as permitted by paragraph
(g)(4) of this section,'' could cause confusion, because paragraph
(g)(4) does not address the basis for the determination of an
examination requirement's impracticality. The submittal of the basis
for determination of the impracticality of an examination requirement
is required by (g)(5)(iii) and the timing of this submittal is
discussed in (g)(5)(iv). Therefore, paragraph (g)(5)(iv) of the final
rule is revised to remove the wording ``and is not included in the
revised inservice inspection program as permitted by paragraph (g)(4)
of this section.''
10 CFR 50.55a(g)(6)(ii)(F)(1)
Comment: The final rule should incorporate by reference Code Case
N-770-1, approved by ASME on Dec. 25, 2009, in lieu of Code Case N-770.
In
[[Page 36244]]
Code Case N-770-1, ``cladding'' was changed to ``onlay'' to eliminate
confusion and misapplication in either installation requirements or
examination/evaluation requirements, or both. The confusion and
misapplication could result from someone applying the existing Code
rules for ``cladding,'' which is not the intent when ``cladding
mitigation'' in N-770 is used. [4-4; 4-27a; 11-3; 11a-34a; 14-3; 14-
34a; 19-1]
NRC Response: The NRC agrees that incorporating by reference Code
Case N-770-1 into the final rule could eliminate a number of the
proposed conditions. Many of the conditions the NRC proposed to impose
on the use of Code Case N-770 have been incorporated into Code Case N-
770-1, as discussed in specific comments related to Code Case N-770.
Therefore, the final rule incorporates by reference Code Case N-770-1,
and does not include most of the conditions on the use of Code Case N-
770 that were included in the proposed rule. The NRC agrees that the
term ``cladding,'' as used by Section XI, does not apply to mitigation
in the context of Code Case N-770. ``Onlay'' is the terminology used in
the code case. The incorporation of Code Case N-770-1 in the final rule
addresses the commenters' recommendation that the final rule use the
terminology ``onlay'' instead of ``cladding.''
10 CFR 50.55a(g)(6)(ii)(F)(2)
Comment: The NRC has typically approved the application of pressure
boundary weld mitigation techniques on a case-by-case basis. All
mitigation techniques discussed in Code Case N-770, with the exception
of Mechanical Stress Improvement Process (MSIP), are the subject of
separate code cases which will be subject to approval by the NRC. MSIP
meets the requirements of Appendix I of Code Case N-770 and has been
separately approved by the NRC. If approved mitigation techniques are
employed, a separate review of the reclassification of the welds as
proposed by the condition in paragraph (g)(6)(ii)(F)(2) should not be
required. [5-2; 8-1; 11a-34b; 14-34b; 16-1; 17-16; 18-4; 19-1; 20-16;
21-8]
NRC Response: The NRC disagrees that a separate NRC review of the
reclassification of welds should not be required for mitigation
techniques approved in ASME code cases. It is the NRC's position that a
separate review of the reclassification of welds will be required
unless NRC-approved mitigation techniques are employed. This condition
provides clarity for the licensee and inspectors for the classification
of each weld. Under the condition, unless there is NRC approval of a
mitigation technique, whether generic or plant specific, such welds
will be classified as category items A-1, A-2 or B of Table 1 of ASME
Code Case N-770-1. All mitigation techniques discussed in Code Case N-
770, with the exception of MSIP, are covered by separate code cases in
various stages of development. These code cases are subject to approval
by the NRC. As ASME completes these mitigation code cases, the NRC will
review and approve them, if appropriate, possibly with conditions. The
NRC uses RG 1.147, which is incorporated by reference in 10 CFR 50.55a,
to endorse approved code cases for generic use. Based on the wording of
paragraph (g)(6)(ii)(F)(2), as the NRC endorses mitigation code cases
in the RG, the rule permits licensees to categorize mitigated welds in
the corresponding Inspection Items in Code Case N-770-1, without a
separate NRC review of the classification or reclassification. No
change to paragraph (g)(6)(ii)(F)(2) was made in the final rule as a
result of this comment.
Comment: The proposed condition in paragraph (g)(6)(ii)(F)(2) is
not consistent with the other proposed conditions in paragraphs
(g)(6)(ii)(F)(6) and (g)(6)(ii)(F)(7) or Code Case N-770. Paragraph
(g)(6)(ii)(F)(6) requires that a weld that has been mitigated by inlay
or corrosion resistant cladding, and then is found to be cracked, be
reclassified and inspected using the frequencies of Inspection Item A-
I, A-2, or B. This indicates that an uncracked weld that has been
mitigated by inlay or corrosion resistant cladding would not be
categorized as Inspection Items A-1, A-2 or B following an acceptable
pre-service examination. Additionally, paragraph (g)(6)(ii)(F)(7)
requires that a weld mitigated by inlay or corrosion resistant cladding
be examined each interval if at hot-leg temperatures and as part of a
25-percent sample plan on a 20-year frequency if at cold-leg
temperatures, which is not consistent with Inspection Item A-1, A-2, or
B. [5-2; 8-1; 11a-34b; 14-34b; 16-1; 17-16; 18-4; 19-1; 20-16; 21-8]
NRC Response: The NRC agrees with the first point about the
inconsistency between paragraphs (g)(6)(ii)(F)(2) and (g)(6)(ii)(F)(6),
but disagrees with the second point about an inconsistency between
paragraphs (g)(6)(ii)(F)(2) and (g)(6)(ii)(F)(7). Proposed paragraph
(g)(6)(ii)(F)(6) referred to welds mitigated by inlay or cladding
rather than referring to welds in Inspection Items G, H, J, and K. The
wording in proposed paragraph (g)(6)(ii)(F)(6) overlooked the step
required by paragraph (g)(6)(ii)(F)(2) to obtain NRC authorization for
an alternative classification of welds as Inspection Items G, H, J, or
K. However, paragraph (g)(6)(ii)(F)(6) of the proposed rule is not
included in the final rule because Code Case N-770-1 addresses the
NRC's concern that was contained in this condition, and Code Case N-
770-1 is incorporated by reference in the final rule.
The NRC disagrees with the commenters' second point. Paragraph
(g)(6)(ii)(F)(7) in the proposed rule correctly referred to, and would
apply to, welds in Inspection Items G, H, J and K. Before welds can be
categorized as Inspection Items G, H, J, or K, the categorization would
first have to be authorized by the NRC under the condition in paragraph
(g)(6)(ii)(F)(2). Therefore, paragraph (g)(6)(ii)(F)(7) in the proposed
rule would be consistent with paragraph (g)(6)(ii)(F)(2). No change to
paragraph (g)(6)(ii)(F)(7) of the proposed rule was made in the final
rule as a result of this comment.
10 CFR 50.55a(g)(6)(ii)(F)(3)
Comment: The proposed condition in paragraph (g)(6)(F)(3) should
not be applied. The final rule approval timing for some plants may be
such that there would not be time to plan and prepare for the required
baseline inspection under the proposed condition in paragraph
(g)(6)(ii)(F)(3) and prepare repair contingencies, (e.g., approval of
the rule in June and the next refueling outage for a plant is in
September). By providing a window of the next two refueling outages,
the required planning and preparation can be accommodated.
Additionally, for baseline examinations already completed to the
requirements of the industry guidance, any condition applied should
recognize these examinations as acceptable for compliance to N-770 and
the NRC Conditions. [5-3; 8-2; 11a-34c; 14-34c; 16-2; 17-17; 18-5; 19-
1; 20-17; 21-9]
NRC Response: The NRC agrees that more time may be needed after the
rule becomes effective for licensees to complete the baseline
examinations, but does not agree that the condition should not be
included in the final rule. The NRC believes that there are welds
within the scope of Code Case N-770 that have not been examined under
the industry program MRP-139, ``Primary System Piping Butt Weld
Inspection and Evaluation Guideline.'' There may also be welds that
received less than complete ASME Code, Section XI, examination coverage
under the MRP-139 program. Paragraph (g)(6)(ii)(F)(3) is necessary to
ensure that adequate
[[Page 36245]]
baseline examinations have been performed on all welds within the scope
of Code Case N-770, since these welds are susceptible to PWSCC. The
need for ensuring the integrity of these welds, beginning with baseline
examinations, has been recognized by the NRC and industry groups for a
number of years. The NRC included paragraph (g)(6)(ii)(F)(3) in the
proposed rule because it believes that the code case requirement
allowing two refueling outages after adoption of the code case to
complete the baseline examinations is inconsistent with the safety
significance of performing the initial inspections of these welds.
The NRC recognizes that the timing in paragraph (g)(6)(ii)(F)(3) as
proposed would, in some cases, constrain planning and preparation
efforts for the required baseline examination. Therefore, for butt
welds that were not in the scope of MRP-139 and did not receive a
baseline examination, the timing in paragraph (g)(6)(ii)(F)(3) in the
final rule is extended to require that these baseline examinations be
completed at the next refueling outage that occurs more than 6 months
from the effective date of the final rule. This change in the condition
would give licensees at least 6 months to plan and prepare for the
baseline examination. If a baseline examination cannot be performed by
the licensee to meet the requirements of paragraph (g)(6)(ii)(F), then
the licensee is required to obtain NRC authorization of alternative
examination requirements in accordance with paragraphs (a)(3)(i) or
(a)(3)(ii).
In response to the comment regarding using examinations performed
prior to issuance of the final rule as baseline examinations for Code
Case N-770, the NRC revised paragraph (g)(6)(ii)(F)(3) in the final
rule to address this option. Previous examinations of these welds can
be credited for baseline examinations if they were performed using
Section XI, Appendix VIII requirements and met the Code-required
examination volume for axial and circumferential flaws of essentially
100 percent. For butt welds that received a MRP-139 examination that
did not fully meet Section XI, Appendix VIII requirements, or achieve
essentially 100-percent coverage, licensees can re-perform the baseline
examination to meet these requirements or obtain NRC authorization of
alternative examination requirements in accordance with paragraph
(a)(3)(i) or (a)(3)(ii) by the end of next refueling outage that occurs
after 6 months from the effective date of the final rule. This
provision acknowledges previous examinations that could satisfy the
Code Case N-770-1 baseline requirement, with NRC authorization of
alternative examination requirements within a reasonable time frame.
A licensee may also choose to use previous inspections of
dissimilar-metal butt welds performed under the plant's ASME Code,
Section XI, Inservice Inspection program to count as meeting the
paragraph (g)(6)(ii)(F)(3) baseline requirement. This is acceptable,
provided the previous inspection falls within the re-inspection period
for welds in ASME Code Case N-770-1, Table 1, Inspection Items A-1, A-
2, and B. Additionally, the NRC-approved alternative examination
coverage for these welds during the current 10-year inservice
inspection interval remain applicable. In all of these cases, the
previously-approved alternative will continue to apply for the duration
authorized by the NRC as the final rule does not revoke previous NRC-
approved alternatives or relief requests.
In the final rule, paragraph (g)(6)(ii)(F)(3) is revised to require
baseline examinations for welds in Table 1, Inspection Items A-1, A-2,
and B, to be performed at the next refueling outage that occurs later
than 6 months after the effective date of the final rule. The rule
allows previous examinations of these welds to be credited for baseline
examinations if they were performed (1) within the re-inspection period
for the weld item in Table 1, and (2) using Section XI, Appendix VIII
requirements and met the Code-required examination volume of
essentially 100 percent. The rule allows other previous examinations
that do not meet these requirements to be used to meet the baseline
examination requirement, provided NRC authorization of alternative
inspection requirements in accordance with 10 CFR 50.55a(a)(3)(i) or
(a)(3)(ii) is granted prior to the end of the next refueling outage
that occurs later than 6 months after the effective date of the final
rule.
10 CFR 50.55a(g)(6)(ii)(F)(5)
Comment: In Code Case N-770-1, approved by the ASME on December 25,
2009, Paragraph--3132.3(b) has been modified, so the adoption of Code
Case N-770-1 would make the proposed condition in paragraph
(g)(6)(ii)(F)(5) no longer necessary. [5-5; 8-4; 11-34e; 14-34e; 16-4;
19-1; 20-19; 21-11]
NRC Response: The NRC agrees with this comment for several reasons.
Code Case N-770, Paragraph --3132.3(b) states that a ``flaw is not
considered to have grown if the size difference (from a previous
examination) is within the measurement accuracy of the NDE technique
employed.'' Use of this terminology may have resulted in a departure
from the past practice when applying the ASME Code, Section XI.
Paragraph (g)(6)(ii)(F)(5) of the proposed rule stated that a flaw is
not considered to have grown if a previously evaluated flaw has
remained essentially unchanged. This wording is consistent with the
requirements and practice of NDE under Section XI. Paragraph--3132.3(b)
of Code Case N-770-1 uses the same wording as contained in paragraph
(g)(6)(ii)(F)(5) of the proposed rule. The revised requirement of Code
Case N-770-1 fully addresses the NRC's concern contained in paragraph
(g)(6)(ii)(F)(5) of the proposed rule. Because the final rule
incorporates by reference Code Case N-770-1, the final rule does not
include the condition of paragraph (g)(6)(ii)(F)(5) from the proposed
rule.
10 CFR 50.55a(g)(6)(ii)(F)(6)
Comment: Code Case N-770-1, approved by the ASME on Dec. 25, 2009,
modified Note 16(c), so the adoption of Code Case N-770-1 would make
the proposed condition in 10 CFR 50.55a(g)(6)(ii)(F)(6) no longer
necessary. [5-6; 8-5; 11a-34f; 14-34f; 16-5; 19-1; 20-20; 21-12]
NRC Response: The NRC agrees with this comment for several reasons.
Code Case N-770 would permit welds mitigated by inlay or cladding
(i.e., onlay) in Inspection Items G, H, J, and K, to remain in those
Inspection Items if cracking were to occur that penetrates through the
thickness of the inlay or onlay. The purpose of an inlay or onlay is to
provide a corrosion-resistant barrier between reactor coolant and the
underlying Alloy 82/182 weld material that is susceptible to PWSCC. If
cracking penetrates through the thickness of an inlay or onlay, the
inspection frequencies of Inspection Items G, H, J, and K would no
longer be appropriate even after satisfying the successive examination
requirements of Paragraph--2420. Paragraph (g)(6)(ii)(F)(6) would
require welds in Inspection Items G, H, J, or K, with cracking that
penetrates beyond the thickness of the inlay or cladding, be
reclassified as Inspection Item A-1, A-2, or B, as appropriate, until
corrected by repair/replacement activity in accordance with IWA-4000 or
by corrective measures beyond the scope of Code Case N-770. A new
sentence added to Note (16)(c) of Code Case N-770-1 states that ``if
cracking penetrates beyond the thickness of the inlay or onlay, the
weld shall be reclassified as Inspection Item A-1, A-2, or B, as
appropriate, until corrected by repair/replacement activity in
accordance with
[[Page 36246]]
IWA-4000 or by corrective measures beyond the scope of this Case (e.g.,
stress improvement).'' The revision of Note (16)(c) in Code Case N-770-
1 fully addresses the NRC concerns contained in paragraph
(g)(6)(ii)(F)(6) of the proposed rule. Because the final rule
incorporates by reference Code Case N-770-1, the final rule does not
include the condition of paragraph (g)(6)(ii)(F)(6) from the proposed
rule.
10 CFR 50.55a(g)(6)(ii)(F)(7)
Comment: The proposed condition is appropriate because the Appendix
VIII supplement has not yet been developed to demonstrate the detection
of flaws in the thin inlay or cladding when the examination is
performed from the outside surface. Code Case N-770-1, approved by the
ASME on Dec. 25, 2009, modified the ``Extent and Frequency of
Examination'' column for Inspection Items G, H, J, and K in Table 1, so
adoption of Code Case N-770-1 would allow the NRC to modify the
proposed condition in paragraph (g)(6)(ii)(F)(7). [5-7; 8-6; 11a-34g;
14-34g; 16-6; 19-1; 20-21; 21-13]
NRC Response: The NRC agrees with this comment. In Code Case N-770,
the Table 1 column titled ``Extent and Frequency of Examination'' for
Inspection Items G, H, J, and K (welds mitigated by inlay or cladding)
only requires a surface examination for welds in Inspection Items G, H,
J, and K if a volumetric examination is performed from the weld inside-
diameter surface. The NRC proposed adding paragraph (g)(6)(ii)(F)(7) on
welds in Inspection Items G, H, J, and K, which would have required
that the ISI surface examination requirements of Table 1 apply whether
the inservice volumetric examinations are performed from the weld
outside diameter or the weld inside diameter. A volumetric examination
performed from the weld outside-diameter surface would not be capable
of detecting flaws in an inlay or onlay. In Code Case N-770-1, the
Table 1 column titled ``Extent and Frequency of Examination'' for
Inspection Items G, H, J, and K contains revised requirements to
perform a surface examination from the weld inside surface and a
volumetric examination performed from either the inside or outside
surface. The revised requirement of Code Case N-770-1 for surface
examination of welds in Inspection Items G, H, J, and K is the same
requirement that was contained in paragraph (g)(6)(ii)(F)(7) of the
proposed rule. Because the final rule incorporates by reference Code
Case N-770-1, the final rule does not include the surface examination
requirement of paragraph (g)(6)(ii)(F)(7) from the proposed rule.
10 CFR 50.55a(g)(6)(ii)(F)(8)
Comment: Code Case N-770-1, approved by the ASME on Dec. 25, 2009,
modified Notes 11(b)(1) and (2), so adoption of Code Case N-770-1 would
make the proposed condition in paragraph (g)(6)(ii)(F)(8) no longer
necessary. [5-9; 8-8; 11a-34h; 16-8; 19-1; 20-23; 21-15]
NRC Response: The NRC agrees with this comment for several reasons.
Inspection Items D, G, and H pertain to mitigation of uncracked butt
welds by stress improvement, weld inlay, and weld onlay, respectively.
Code Case N-770 does not explicitly preclude deferral of the first
examination of Items D, G, and H following mitigation to the end of the
interval. Therefore, the NRC proposed paragraph (g)(6)(ii)(F)(8) to
ensure that the initial examinations of welds in Inspection Items D, G,
and H take place on an appropriate schedule to verify the effectiveness
of the mitigation process. Note (11), which pertains to deferral of the
first examinations after mitigation, was revised in Code Case N-770-1.
The revised requirements of Code Case N-770-1, Note (11), indicate that
the first examinations following mitigation are to be performed within
10 years following mitigation for Item D butt welds, but can be
performed any time within the 10 years. The revised requirements of
Code Case N-770-1, Note (11), indicate that the first examinations
following mitigation are to be performed as specified in Table 1 for
Items G and H butt welds. The revised requirements of Code Case N-770-1
preclude deferral of the first examinations of Item D butt welds beyond
the 10 years allowed by Table 1, and preclude deferral of the first
examinations for Item G and H butt welds to the end of an interval, if
that is later than the specified time in Table 1. The revision of Note
(11) in Code Case N-770-1 addresses the NRC's concerns in paragraph
(g)(6)(ii)(F)(8) of the proposed rule. Because the final rule
incorporates by reference Code Case N-770-1, the final rule does not
include the condition of paragraph (g)(6)(ii)(F)(8) from the proposed
rule.
10 CFR 50.55a(g)(6)(ii)(F)(9)
Comment: Code Case N-770-1, approved by the ASME on Dec. 25, 2009,
modified paragraph I-1.1, so adoption of Code Case N-770-1 would make
the proposed condition in paragraph (g)(6)(ii)(F)(9) no longer
necessary. [5-10; 8-9; 11-34i; 14-34i; 16-9; 19-1; 20-24; 21-16]
NRC Response: The NRC agrees with this comment for several reasons.
Code Case N-770, Appendix I, Measurement or Quantification Criteria I-
1.1, requires an analysis that assumes the pre-stress-improvement,
residual-stress condition resulting from a construction weld repair
from the inside diameter to a depth of 50-percent of the weld
thickness. Code Case N-770 does not specify the circumferential extent
of the weld repair that must be assumed. Paragraph (g)(6)(ii)(F)(9) of
the proposed rule would require that in applying Measurement or
Quantification Criterion I-1.1, the weld repair be assumed to extend
360[deg] around the weld. Code Case N-770-1 specifies in Measurement or
Quantification Criterion I-1.1 that the weld repair be assumed to
extend 360[deg] around the weld. The addition of the circumferential
extent of the assumed weld repair in Appendix I of Code Case N-770-1
fully addresses the NRC's concern contained in paragraph
(g)(6)(ii)(F)(9) of the proposed rule. Because the final rule
incorporates by reference Code Case N-770-1, the final rule does not
include the condition of paragraph (g)(6)(ii)(F)(9) from the proposed
rule.
10 CFR 50.55a(g)(6)(ii)(F)(10)
Comment: Code Case N-770-1, approved by the ASME on Dec. 25, 2009,
modified paragraph I-2.1, so adoption of Code Case N-770-1 in lieu of
N-770 in the final rule would allow the NRC to remove this condition.
[5-11; 8-10; 11-34j; 14-34j; 16-10; 19-1; 20-25; 21-17]
NRC Response: The NRC agrees with this comment for several reasons.
Code Case N-770, Appendix I, Measurement or Quantification Criterion I-
2.1, requires that an analysis or demonstration test account for load
combinations that could cause plastic ratcheting. This wording is
inappropriate since this criterion pertains to the permanence of a
mitigation process by stress improvement, and ``shakedown'' rather than
``ratcheting'' is the phenomenon that could lead to lack of permanence
of the mitigation. Paragraph (g)(6)(ii)(F)(10) of the proposed rule
would require that the last sentence of Measurement or Quantification
Criterion I-2.1 be replaced with a sentence that uses the correct
terminology. Code Case N-770-1 of Appendix I, Measurement or
Quantification Criterion I-2.1, requires that an analysis or
demonstration test account for load combinations that could relieve
stress due to shakedown. The revised requirement of Code Case N-770-1
fully addresses the NRC's
[[Page 36247]]
concern contained in paragraph (g)(6)(ii)(F)(10) of the proposed rule.
Because the final rule incorporates by reference Code Case N-770-1, the
final rule does not include the condition of paragraph
(g)(6)(ii)(F)(10) from the proposed rule.
10 CFR 50.55a(g)(6)(ii)(F)(11)
Comment: The NRC proposes to add a condition to require that in
applying Measurement or Quantification Criterion I-7.1 of Appendix I,
an analysis be performed using IWB-3600 evaluation methods and
acceptance criteria to verify that the mitigation process will not
cause any existing flaws to grow. However, measurement or
Quantification Criterion I-7.1 permits the growth of existing flaws in
welds mitigated by stress improvement recognizing that flaw growth can
also be caused by fatigue crack growth, which cannot be precluded.
Criterion I-7.1, however, also includes the requirement that the
mitigation process will not cause any existing flaws to become
unacceptable.
Code Case N-770-1 modified paragraph 1-7.1, so adoption of Code
Case N-770-1 would allow the NRC to remove proposed condition 10 CFR
50.55a(g)(6)(ii)(F)(11). [5-12; 8-11; 11a-34k; 14-34k; 16-11; 19-1; 20-
26; 21-18]
NRC Response: The NRC agrees with this comment for several reasons.
Code Case N-770, Appendix I, Performance Criteria I-7, requires that
the stress intensity factor at the depth of the flaw (the flaw tip) be
determined using combined residual and operating stresses, and shall be
zero. Under paragraph I-7, no flaw growth could occur if the stress
intensity factor is zero at the flaw tip using the combined residual
and operating stresses. The following section of the code case,
Measurement or Quantification Criteria I-7.1, requires that an analysis
be performed to verify that the mitigation process will not cause any
existing flaws to become unacceptable. The NRC proposed adding
paragraph (g)(6)(ii)(F)(11), because it appeared that, contrary to the
requirements of I-7, the analysis required by the Mitigation or
Quantification Criteria may have allowed flaw growth, even growth by
primary-water stress corrosion cracking.
The revised requirements of Code Case N-770-1, Appendix I,
Performance Criteria I-7, state that the stress intensity factor at the
depth of the flaw shall be determined using combined residual and
steady-state operating stresses, and shall not be greater than zero. By
adding the words ``steady-state'' in I-7 of Code Case N-770-1, and
maintaining the stress intensity factor at the flaw tip to zero or
less, primary-water stress corrosion cracking would not be expected to
occur. The next section of the Code Case N-770-1, Measurement or
Quantification Criteria I-7.1, requires that an analysis be performed,
using IWB-3600 evaluation methods and acceptance criteria, to verify
that the mitigation process will not result in any existing flaws
becoming unacceptable. The revised wording in I-7 and I-7.1 would only
allow flaw growth under non-steady-state operating stresses (fatigue)
and would ensure that standard ASME Code analysis methods are used to
limit any fatigue growth to acceptable levels. Code Case N-770-1,
Appendix I, uses different wording than proposed in paragraph
(g)(6)(ii)(F)(11). However, the revised requirements in Code Case N-
770-1 fully address the NRC's concern that the criteria of Code Case N-
770, Appendix I, were contradictory and may have permitted flaw growth
by PWSCC. Because the final rule incorporates by reference Code Case N-
770-1, the final rule does not include the condition of paragraph
(g)(6)(ii)(F)(11) from the proposed rule.
10 CFR 50.55a(g)(6)(ii)(F)(13)
Comment: Code Case N-770-1 modified the wording of the Extent and
Frequency of Examination for Inspection Items C and F, so adoption of
Code Case N-770-1 would allow removal of the proposed condition in 10
CFR 50.55a(g)(6)(ii)(F)(13). [5-14; 8-13; 11-34m; 14-34m; 16-13; 19-1;
20-28; 21-19]
NRC Response: The NRC agrees with this comment. Inspection Items C
and F pertain to butt welds mitigated by full structural weld overlays.
Note (10) of Code Case N-770 requires that welds in Inspection Items C
and F that are not included in the 25-percent sample be examined prior
to the end of the mitigation evaluation period if the plant is to be
operated beyond that time. Proposed paragraph (g)(6)(ii)(F)(13) was
written because Code Case N-770 does not contain a similar requirement
to inspect prior to the end of the mitigation evaluation period for
welds that are included in the 25-percent sample. Code Case N-770-1,
Table 1, requires that for welds in the Inspection Items C and F 25-
percent inspection sample that have a design life of less than 10
years, at least one inservice inspection shall be performed prior to
exceeding the life of the overlay. The revised requirements in Code
Case N-770-1 fully address the NRC concern that Inspection Item C and F
welds in the 25-percent inspection sample may not have been inspected
prior to the end of the life of the overlay. Because the final rule
incorporates by reference Code Case N-770-1, the final rule does not
include the condition of paragraph (g)(6)(ii)(F)(13) from the proposed
rule.
10 CFR 50.55a(g)(6)(ii)(F)(14)
Comment: The change in the dimension to be used in determining the
thickness ``t'' in the acceptance criteria should be adopted, but the
NRC-proposed condition should not be adopted, for the following reason.
The proposed condition in paragraph (g)(6)(ii)(F)(14) would cause a
conflict in the definition of the required examination volume A-B-C-D,
with Figures 2(a) and 5(a) showing the correct definition of the
required volume and Figures 2(b) and 5(b) combined with the NRC's
proposed condition defining a larger and unintended examination volume
(by extending the examination volume of an overlay in both axial
directions).
Code Case N-770-1 removed the \1/2\-inch (13 mm) dimension shown in
Figures 2(b) and 5(b) of Code Case N-770 and replaced them with
dimensions ``X'' and ``Y''. The notes beneath each figure define
dimensions ``X'' and ``Y''.
Concurrent with the change in the \1/2\-inch dimension, Code Case
N-770-1 also removed the examination volume A-B-C-D from Figures 2(b)
and 5(b). This change was made to clarify that Figures 2(b) and 5(b)
were not defining any examination volume, but were only defining the
thicknesses to use in applying IWB-3514 acceptance standards. The
thickness ``t2'' in Figures 2(b) and 5(b) was also revised/corrected in
Code Case N-770-1 to reflect the total thickness of the original pipe
plus the overlay at the location of the flaw.
The adoption of Code Case N-770-1 in lieu of N-770 in the final
rule would allow the NRC to remove the proposed condition in paragraph
(g)(6)(ii)(F)(14). If Code Case N-770-1 is not adopted in the final
rule, the proposed NRC condition needs to be revised to either require
the use of Figures 2(b) and 5(b) in Code Case N-770-1, or provide
specific figures to use with the condition that are identical to
Figures 2(b) and 5(b) in Case N-770-1. [11a-34n]
NRC Response: The NRC agrees with this comment for several reasons.
Code Case N-770, Figures 2(b) and 5(b), contain information on
component thicknesses to be used in application of the acceptance
standards of ASME Code, Section XI, lWB-3514, to evaluate flaws
detected during preservice and inservice inspection of weld overlays.
The \1/2\-inch (13 mm) dimensions shown
[[Page 36248]]
in Figures 2(b) and 5(b) could have resulted in a non-conservative
application of the acceptance standards. The appropriate dimensions are
a function of the nominal thickness of the nozzle and pipe being
overlaid rather than a single, specified value (\1/2\-inch) on either
side of the weld for all pipes and nozzles. The revision in Code Case
N-770-1 of the \1/2\-inch dimension in Figures 2(b) and 5(b) to be used
in determining the thickness ``t'' in the acceptance standards is
consistent with paragraph (g)(6)(ii)(F)(14) of the proposed rule.
Concurrent with the change in the \1/2\ inch dimension, Code Case N-
770-1 also removed the examination volume A-B-C-D from Figures 2(b) and
5(b). This change was made to clarify that Figures 2(b) and 5(b) were
not defining an examination volume, but were defining the thicknesses
to use in applying IWB-3514 acceptance standards, that is, the
locations in the weld overlay where each of the two thicknesses, ``t1''
and ``t2'', would apply to flaws. The thickness ``t2'' in Figures 2(b)
and 5(b) was also corrected in Code Case N-770-1 to reflect the total
thickness of the original pipe plus the overlay at the location of the
flaw. The changes to Figures 2(b) and 5(b) that are reflected in Code
Case N-770-1 address the NRC's concern regarding non-conservative
application of acceptance standards during preservice inspection. The
NRC agrees that the other changes made to Figures 2(b) and 5(b) in Code
Case N-770-1 correct errors in these figures in Code Case N-770.
Because the final rule incorporates by reference Code Case N-770-1, the
final rule does not include the condition of paragraph
(g)(6)(ii)(F)(14) from the proposed rule.
10 CFR 50.55a(g)(6)(ii)(F)(15)
Comment: The condition as proposed will not accomplish what was
intended. As proposed, for a flaw in the original nozzle/weld material
we would have to use ``t'' equal to the inlay/onlay thickness to
determine the acceptable size per IWB-3514. Nothing would be acceptable
under that condition. For flaws that are not contained within the
inlay/onlay/cladding, the value of ``t'' used should be the full
structural wall thickness. If the NRC feels that there still needs to
be a condition specified in this area, it needs to be re-structured to
specify appropriate ``t'' values for flaws that are contained within
the inlay/onlay, and t values for flaws that are contained in the
original structural material. [11a-34o; 14-34o; 17-20; 18-9; 19-1]
NRC Response: The NRC agrees that the condition in paragraph
(g)(6)(ii)(F)(15) of the proposed rule would be more effective if it
were revised as recommended. The condition in paragraph
(g)(6)(ii)(F)(15) of the proposed rule dealt with the value of ``t'' to
use for flaws found in an inlay or onlay. Although a value of ``t''
equal to the full structural wall thickness is inferred by the code
case, the condition did not address the value of ``t'' to be used for
flaws that are not contained within the inlay or onlay material. In the
final rule this condition has been revised to clarify that for
Inspection Items G, H, J, and K, when applying the acceptance standards
of ASME B&PV Code, Section XI, IWB-3514, for planar flaws that are not
contained within the inlay or onlay material, the thickness ``t'' in
IWB-3514 is the combined thickness of the inlay or onlay and the
dissimilar metal weld.
III. Discussion of NRC Approval of New Edition and Addenda to the
Codes, ASME Code Cases N-722-1 and N-770-1, and Other Changes to 10 CFR
50.55a
The NRC is amending its regulations to incorporate by reference the
2005 Addenda through 2008 Addenda of Section III, Division 1, and
Section XI, Division 1 of the ASME B&PV Code; and the 2005 Addenda and
2006 Addenda of the ASME OM Code into 10 CFR 50.55a. The NRC also is
incorporating by reference Code Case N-770-1, and revision 1 to Code
Case N-722, which was incorporated by reference into the NRC's
regulations on September 10, 2008 (73 FR 52729).
The NRC follows a three-step process to determine acceptability of
new provisions in new editions and addenda to the Codes, and the need
for conditions on the uses of these Codes. This process was employed in
the review of the Codes that are the subjects of this rule. First, NRC
staff actively participates with other ASME committee members with full
involvement in discussions and technical debates in the development of
new and revised Codes. This includes a technical justification in
support of each new or revised Code. Second, the NRC committee
representatives discuss the Codes and technical justifications with
other cognizant NRC staff to ensure an adequate technical review.
Finally, the NRC position on each Code is reviewed and approved by NRC
management as part of the rule amending 10 CFR 50.55a to incorporate by
reference new editions and addenda of the ASME Codes, and conditions on
their use. This regulatory process, when considered together with the
ASME's own process for developing and approving ASME Codes, provides
reasonable assurances that the NRC approves for use only those new and
revised Code edition and addenda (with conditions as necessary) that
provide reasonable assurance of adequate protection to public health
and safety and that do not have significant adverse impacts on the
environment.
The NRC reviewed changes to the Codes in the editions and addenda
of the Codes identified in this rulemaking. The NRC concluded, in
accordance with the process for review of changes to the Codes, that
each of the editions and addenda of the Codes, and the 1994 Edition of
NQA-1, are technically adequate, consistent with current NRC
regulations, and approved for use with the specified conditions.
The following paragraphs contain the NRC's evaluation of the
changes to the Code editions and addenda (including new Code
provisions) and Code Cases N-722-1 and N-770-1, where the NRC added
new, revised existing, or removed conditions in 10 CFR 50.55a.
Quality Standards, ASME Codes and Institute of Electrical and
Electronics Engineers (IEEE) Standards, and Alternatives
10 CFR 50.55a(a)
The NRC is amending Sec. 50.55a(a) to add a new paragraph heading
entitled ``Quality standards, ASME Codes and IEEE standards, and
alternatives.'' This will be consistent with paragraph headings
throughout 10 CFR 50.55a.
Applicant/Licensee-Proposed Alternatives to the Requirements of 10 CFR
50.55a
10 CFR 50.55a(a)(3)
The NRC is amending Sec. 50.55a(a)(3) to clarify that an
alternative must be submitted to, and authorized by, the NRC prior to
implementing the alternative. Licensees have misinterpreted Sec.
50.55a(a)(3) and erroneously concluded that it is permissible to obtain
NRC authorization of an alternative after its implementation. The final
rule requires that alternatives to the requirements of Sec. Sec.
50.55a(c), (d), (e), (f), (g), and (h) must be submitted to, and
authorized by, the NRC prior to implementing the alternatives.
Standards Approved for Incorporation by Reference
10 CFR 50.55a(b)
The NRC is amending Sec. 50.55a(b) to add a new paragraph heading
entitled ``Standards approved for incorporation by reference.'' This
will be consistent with paragraph headings throughout 10 CFR 50.55a.
[[Page 36249]]
The question has arisen many times in the past of whether
Subsection NE, ``Class MC Components;'' Subsection NF, ``Supports;''
Subsection NG, ``Core Support Structures;'' and Appendices of the ASME
B&PV Code, Section III, are NRC requirements. The NRC is clarifying in
this section how the regulations in 10 CFR 50.55a apply to these
Section III subsections and appendices. This discussion sets forth the
NRC's views regarding the applicable NRC requirements, clarifies which
portions of Section III are approved for use by applicants and
licensees, identifies which portions of Section III are NRC
requirements, and identifies which portions of Section III are not
covered by the regulations in 10 CFR 50.55a. The requirements of
Subsection NH, ``Class 1 Components in Elevated Temperature Service,''
of Section III are already addressed in Sec. 50.55a(b)(1)(vi), and the
bases for these requirements have been discussed in the final rule (69
FR 58804) issued on October 1, 2004, that amended 10 CFR 50.55a to
incorporate by reference the 2001 Edition up to and including the 2003
Addenda of the ASME Code, Section III.
First, it should be noted that in 10 CFR 50.55a, the NRC mandates
the use of Section III, Division 1, rules for ASME Code Class 1, 2, and
3 components in 10 CFR 50.55a(c), (d) and (e), respectively.
Specifically, 10 CFR 50.55a(c), (d) and (e) state that for applicants
constructing a nuclear power plant, those components which are part of
the reactor coolant pressure boundary must meet the requirements for
Class 1 components in Section III (e.g., Subsection NB, ``Class 1
Components''); components classified as Quality Group B must meet the
requirements for Class 2 components (e.g., Subsection NC, ``Class 2
Components''); and components classified as Quality Group C must meet
the requirements for Class 3 components (e.g., Subsection ND, ``Class 3
Components''). The NRC considers the rules of Subsection NCA and
Section III mandatory appendices to be mandated as well, but only as
they apply to Class 1, 2, and 3 components because the language in 10
CFR 50.55a(c), (d) and (e) also covers general requirements in
Subsection NCA and mandatory appendices in Section III that are
applicable to Class 1, 2, and 3 components.
In addition, the introductory text of 10 CFR 50.55a(b) states, in
part, that the ASME Code, Section III, is approved for incorporation by
reference by the Director of the Federal Register pursuant to 5 U.S.C.
552(a) and 1 CFR part 51. However, the regulatory language does not
identify specific subsections in Section III that are incorporated by
reference, and one can only assume that all of Section III (including
all subsections, appendices and Division 2 and 3 rules) are
incorporated by reference. Although it is clear that Subsections NB, NC
and ND are regulatory requirements because they are mandated by 10 CFR
50.55a(c), (d) and (e) as discussed in this document, the lack of
specific rule language in 10 CFR 50.55a mandating the use of
Subsections NE, NF, NG, and the Section III mandatory (roman numeral)
appendices has created confusion about the regulatory requirements
applicable to Subsections NE, NF, and NG, and the Section III mandatory
appendices. Subsection NE provides rules for constructing metal
containment components (Class MC). Subsection NF provides rules for
constructing supports for Class 1, 2, 3, and MC components. Subsection
NG provides rules for constructing reactor core support structures. The
Section III mandatory appendices are used in conjunction with the
aforementioned subsections. In this sense, ``constructing'' is an all-
inclusive term that comprises the design, fabrication, installation,
examination, testing, inspection and selection of materials for nuclear
power plant components.
The NRC is, therefore, clarifying that when Subsections NE, NF, NG,
and the Section III mandatory appendices are incorporated by reference,
but not mandated, these subsections are not NRC requirements. Rather,
the NRC considers Subsections NE, NF, NG and the Section III mandatory
appendices to be approved by the NRC for use by applicants and
licensees of nuclear power plants by virtue of the NRC's overall
approval of Section III, Division 1 rules without condition. In this
manner, approval of the rules in Subsections NE, NF, NG, and the
Section III mandatory appendices is similar to regulatory guidance
provided in NRC RGs in that it provides an acceptable method for
meeting NRC requirements and, in this particular case, in 10 CFR part
50, Appendix A, General Design Criterion (GDC) 1, ``Quality standards
and records.'' Applicants and licensees may propose means other than
those specified by the provisions in Subsections NE, NF, NG, and the
Section III mandatory appendices for meeting the applicable regulation.
It should be noted that the NRC reviews an applicant's proposed means
of meeting the requirements of GDC 1 as part of its review of an
application for each manufacturing license, standard design approval,
standard design certification and combined license under 10 CFR part 52
and for each construction permit and operating license under 10 CFR
part 50 using the guidelines of NRC NUREG-0800, ``Standard Review Plan
[SRP] for the Review of Safety Analysis Reports for Nuclear Power
Plants--LWR Edition,'' and applicable regulatory guides. During its
review of new reactor designs under 10 CFR part 52, the NRC is
reviewing the criteria and extent of compliance of standard plant
designs and combined licenses with the rules of the specific edition
and addenda to Subsections NE, NF, NG, and the associated Section III
mandatory appendices for applicability to these new reactor designs.
The process being used by the NRC in the review of Subsections NE, NF,
NG, and the Section III mandatory appendices for new reactors as
described in this document is essentially the same process used by the
NRC for the licensing of all nuclear power plants since the SRP was
first issued in 1975. Therefore, this clarification does not establish
new positions or requirements in the regulatory application of
Subsections NE, NF, NG, and the Section III mandatory appendices to the
construction of nuclear power plants.
Because the NRC staff participates on the ASME Code committees in
the development of any revisions to Subsections NE, NF, NG, and the
Section III mandatory appendices, the NRC is cognizant of the
acceptability of the Code rules applicable to Subsections NE, NF, NG
and the Section III mandatory appendices. NRC's use of consensus
technical standards meets the requirements of Public Law 104-113,
National Technology Transfer and Advancement Act of 1995. Additional
discussion on NRC's compliance with the NTTAA is set forth in Section
VII, ``Voluntary Consensus Standards,'' of this document.
Consistent with this discussion, the NRC did not substantially
change the language in the introductory text to 10 CFR 50.55a(b). The
NRC is modifying the regulatory language in the introductory text of 10
CFR 50.55a(b) to clarify that non-mandatory appendices are excluded
from Section III rules that are incorporated by reference because the
NRC does not review the acceptability of non-mandatory Section III
appendices. Similarly, the NRC is clarifying in the introductory text
of 10 CFR 50.55a(b) that only Division 1 rules of Section III and
Section XI are incorporated by reference (i.e., Divisions 2 and 3 rules
are not incorporated by reference). The NRC also is
[[Page 36250]]
incorporating by reference ASME Code Case N-722-1, ``Additional
Examinations for PWR Pressure Retaining Welds in Class 1 Components
Fabricated With Alloy 600/82/182 Materials Section XI, Division 1,''
and Code Case N-770-1, ``Alternative Examination Requirements and
Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt
Welds Fabricated with UNS N06082 or UNS W86182 Weld Filler Material
with or without Application of Listed Mitigation Activities.''
ASME B&PV Code, Section III
Introductory Text to 10 CFR 50.55a(b)(1)
The NRC is amending the introductory text of Sec. 50.55a(b)(1) to
clarify that references to Section III refer to Section III of the ASME
Boiler and Pressure Vessel Code.
10 CFR 50.55a(b)(1)(ii) Weld-Leg Dimensions
The NRC is amending Sec. 50.55a(b)(1)(ii) in order to apply the
conditions currently in Sec. 50.55a(b)(1)(ii) to the latest Edition
and Addenda incorporated by reference in this rulemaking. The current
regulations in Sec. 50.55a(b)(1)(ii) outline the conditions on the use
of stress indices used for welds in piping design under Subarticles NB-
3600, NC-3600, and ND-3600 of the ASME B&PV Code. The current
regulations are based on the NRC's concern about the undersized weld-
leg dimension of less than 1.09tn, which results in a weld
which is weaker than the pipe to which it is adjoined. The reasons for
the current condition in 10 CFR 50.55a(b)(1)(ii) are articulated in a
previous NRC rulemaking (64 FR 51370; September 22, 1999).
In the proposed rule, the NRC proposed a revision to the condition
identified in Sec. 50.55a(b)(1)(ii) to address the NRC concerns with
the undersized welds (Cx=0.75 tn), which are not
acceptable because the current ASME Code design rules would result in a
circumferential, fillet-welded or socket-welded joint where the weld
size is smaller than the adjoining pipe wall thickness, which makes the
weld weaker than the pipe. The proposed rule also included an editorial
addition of a condition on the use of paragraph NB-3683.4(c)(2). The
proposed rule indicated that the use of paragraph NB-3683.4(c)(1) is
currently not allowed and would continue to be prohibited in the
proposed rulemaking. The addition of the condition on the use of
paragraph NB-3683.4(c)(2) is purely editorial in nature since, by
imposing a condition on the use of NB-3683.4(c)(1), the regulations
would inherently impose a condition on the use of NB-3683.4(c)(2) given
their use within Section III of the ASME B&PV Code. Therefore, this
condition in the proposed rule was not new from a technical standpoint.
Also, an editorial correction was proposed regarding Footnote 11, which
should be Footnote 13 for the 2004 Edition through the 2008 Addenda in
Figure NC-3673.2(b)-1 and Figure ND-3673.2(b)-1.
For licensees and applicants using the 1989 Addenda through the
latest edition and addenda of Section III of the ASME B&PV Code
incorporated by reference in Sec. 50.55a(b)(1), the final rule
prohibits applicants and licensees from applying the following ASME
Code provisions: subparagraphs NB-3683.4(c)(1) and NB-3683.4(c)(2) and
Footnote 11 from the 1989 Addenda through the 2003 Addenda, or Footnote
13 from the 2004 Edition through the 2008 Addenda, to Figures NC-
3673.2(b)-1 and ND-3673.2(b)-1. The final rule requires applicants and
licensees to adhere to these prohibitions when considering welds with
leg size less than 1.09tn.
The NRC received a number of public comments regarding the proposed
modification to Sec. 50.55a(b)(1)(ii), all of which disagreed with the
proposed rule language. The disagreements were based on the assertion
that the proposed rule language was not referencing the correct ASME
B&PV Code provisions on weld sizes. However, the NRC disagreed with
these public comments due to the fact that the language in the proposed
rule was merely a modification to a current condition in the existing
regulations and none of the public comments received on the proposed
modification to Sec. 50.55a(b)(1)(ii) present any new arguments or
information that would cause the NRC to revisit its determination
described in the previous rulemaking. As previously stated, the reasons
for the current condition in 10 CFR 50.55a(b)(1)(ii) are articulated in
a previous NRC rulemaking (64 FR 51370; September 22, 1999). Therefore,
no change was made to paragraph Sec. 50.55a(b)(1)(ii) of the final
rule as a result of these comments. The complete bases for making no
modifications to the proposed rule are found in the public comment
response document.
10 CFR 50.55a(b)(1)(iii) Seismic Design of Piping
The NRC is amending Sec. 50.55a(b)(1)(iii) to explicitly prohibit
the use of Subarticles NB-3200, NB-3600, NC-3600 and ND-3600 from the
1994 Addenda through the 2005 Addenda of Section III of the ASME B&PV
Code for the seismic design of piping. However, the amendment to Sec.
50.55a(b)(1)(iii) does permit the use of Subarticle NB-3200 from the
2004 Edition through the 2008 Addenda of the ASME Code for the seismic
design of piping, subject to the new condition identified as Sec.
50.55a(b)(1)(iii)(A). The amendment to Sec. 50.55a(b)(1)(iii) also
permits the use of Subarticles NB-3600, NC-3600 and ND-3600 from the
2006 Addenda through the 2008 Addenda of Section III of the ASME B&PV
Code for the seismic design of piping, subject to a new condition
identified as Sec. 50.55a(b)(1)(iii)(B).
The current requirements regarding piping seismic rules in Section
III of the ASME B&PV Code were first introduced in the 1994 Addenda to
the ASME B&PV Code. These rules were subsequently modified in the 2001
Edition and 2002 Addenda to the ASME B&PV Code. The current regulations
in Sec. 50.55a(b)(1)(iii) only allow the use of Subarticles NB-3200,
NB-3600, NC-3600, and ND-3600 from the 1993 Addenda and earlier
editions and addenda of the ASME B&PV Code, Section III for the seismic
design of piping.
As noted, the amendment to Sec. 50.55a(b)(1)(iii) includes the
addition of a new condition identified as Sec. 50.55a(b)(1)(iii)(A).
The condition in Sec. 50.55a(b)(1)(iii)(A) resolves an issue
identified by the NRC regarding the inclusion of reversing dynamic
loads when calculating the primary bending stresses for Level B service
limits. Also, the amendment to Sec. 50.55a(b)(1)(iii) includes the
addition of a new condition identified as Sec. 50.55a(b)(1)(iii)(B).
The condition in Sec. 50.55a(b)(1)(iii)(B) relates to the use of the
Do/t ratio and material requirements of NB-3656(b) when
applying the 2006 Addenda through the 2008 Addenda of Section III of
the ASME B&PV Code to the seismic design of piping.
In the proposed rule, the NRC proposed an amendment to Sec.
50.55a(b)(1)(iii) which would have allowed the use of the latest
edition and addenda of Section III of the ASME B&PV Code, incorporated
by reference in this rulemaking, subject to three new conditions
identified as Sec. 50.55a(b)(1)(iii)(A), (b)(1)(iii)(B), and
(b)(1)(iii)(C). These additional requirements would have provided three
conditions on the use the latest edition and addenda of Section III of
the ASME B&PV Code incorporated by reference in the current rulemaking,
as they apply to the seismic design of piping. As a result of public
comments received, the final rule retains only two of the original
three conditions with respect to the use of the editions and
[[Page 36251]]
addenda of Section III of the ASME B&PV Code incorporated by reference
in Sec. 50.55a(b)(1) for the seismic design of piping.
In the proposed rule, the NRC proposed an additional paragraph
identified as Sec. 50.55a(b)(1)(iii)(A) which addressed the NRC's
position regarding the B2' indices in paragraph NB-3656 of
Section III of the ASME B&PV Code. This condition would have stipulated
that the value of B2' should be no less than
0.75B2 (from Table NB-3681(A)-1) when applying the 2006
Addenda through the 2008 Addenda of Section III of the ASME B&PV Code
for the seismic design of piping. The NRC proposed this condition to
address the possibility that ferritic steels may exhibit lower margins
and a decrease in toughness at higher temperatures due to dynamic
strain aging.
A number of public comments were received regarding the proposed
condition on the B2' indices, all of which cited ASME
Position Paper STP-NU-008, issued on November 6, 2009, as the bases for
eliminating the proposed condition. This position paper presents
information demonstrating that dynamic strain aging at typical seismic
strain rates is insignificant and that adequate margin exists between
the ASME Section III code criteria and the ultimate moment under
dynamic cyclic loading (``adequate margin'' refers to the margin
recommended in Appendix III of NUREG/CR-5361). The NRC agreed with the
comments, and considers the previous concerns regarding the possible
reduction in margin due to dynamic strain aging effectively resolved
based on the information found in the aforementioned ASME position
paper. Therefore, as a result of public comments received, the final
rule does not include this condition. Additionally, as a result of the
deletion of this condition from the final rule, the paragraphs which
were identified as Sec. 50.55a(b)(1)(iii)(B) and Sec.
50.55a(b)(1)(iii)(C) in the proposed rule are identified as Sec.
50.55a(b)(1)(iii)(A) and Sec. 50.55a(b)(1)(iii)(B) in the final rule.
A more comprehensive discussion regarding the bases for this change can
be found in the public comment response document.
In the proposed rule, the NRC proposed an additional paragraph
identified as Sec. 50.55a(b)(1)(iii)(B) which addressed the NRC's
position regarding Note (1) of Figure NB-3222-1 of Section III of the
ASME B&PV Code. The NRC proposed this condition based on the premise
that while the inclusion of reversing dynamic loads in the calculation
of primary bending stresses for Level B service limits may not be
warranted when the Operating Basis Earthquake is not included in the
design basis for the facility, at other times these loads must be
considered. Such is the case when a licensee's Operating Basis
Earthquake level is more than one-third the value of the Safe Shutdown
Earthquake. However, the current wording of Note (1) in Figure NB-3222-
1 of Section III of the ASME B&PV Code does not account for this
situation.
Multiple public comments were received regarding this proposed
condition and most generally concurred with the proposed language.
However, all of the public comments received indicated that additional
specificity should be provided in the condition by adding the words,
``by NB-3223(b)'' immediately after the word, ``required'' in the
proposed wording for Sec. 50.55a(b)(1)(iii)(B). The NRC agreed with
the public commenters based on the fact that the suggestion within the
comment results in a more direct application of the proposed condition
in that there is no ambiguity as to how the condition applies with
respect to the seismic design of piping. The final rule includes
additional information regarding the applicability of this condition by
noting the specific subparagraph (NB-3223(b)) for which this condition
applies when the 2006 Addenda through the 2008 Addenda of Section III
of the ASME B&PV Code are used for the seismic design of piping as a
result of public comments received regarding this condition.
Additionally, as a result of public comments, the final rule regarding
this condition is identified as Sec. 50.55a(b)(1)(iii)(A). The
complete bases for this change can be found in the public comment
response document.
In the proposed rule, the NRC proposed an additional paragraph
identified as Sec. 50.55a(b)(1)(iii)(C) which addressed the NRC's
position regarding the limitation on the Do/t ratio of ASME
Class 1, 2 and 3 piping when applying Subarticles NB-3600, NC-3600 and
ND-3600 in the 2006 Addenda through the 2008 Addenda of Section III of
the ASME B&PV Code. This proposed addition would have placed a
condition on the Do/t ratio by requiring this value to be no
greater than 40 when applying Subarticles NB-3600, NC-3600, or ND-3600
in the 2006 Addenda through the 2008 Addenda of Section III of the ASME
B&PV Code for the seismic design of piping.
The public comment responses received regarding this proposed
condition all indicated that the condition which the NRC was proposing
already existed within the code, except for one anomaly. Specifically,
the comments noted that the limitation on the Do/t ratio is
already contained in NB-3656(b), NC/ND-3653.1(b), NC/ND-3655(b), and,
by reference to the Level D requirements, NB-3655.2(b) and NC/ND-
3654.2(b). However, the comments also noted that the Do/t
ratio limitation is not inherent or explicit for Level B service limits
in Class 1 piping. As such, all of the comments suggested that the
focus of the proposed condition be narrowed to capture the condition
where it is not already included within the ASME Code provisions. The
NRC agreed with these comments.
The final rule includes a provision for the seismic design of Class
1 piping which requires the material and Do/t requirements
of NB-3656(b) to be met for all Service Limits when the Service Limits
include reversing dynamic loads, and the alternative rules for
reversing dynamic loads are used as a result of the public comments
received on this condition. Additionally, as a result of public
comments, the final rule regarding the condition on the Do/t
requirements is identified as Sec. 50.55a(b)(1)(iii)(B). The complete
bases for this change can be found in the public comment response
document.
10 CFR 50.55a(b)(1)(iv) Quality Assurance
The NRC is amending Sec. 50.55a(b)(1)(iv) to be consistent with a
revised quality assurance provision in the 2006 Addenda of the ASME
B&PV Code, Section III, Subsection NCA. The final rule allows the use
of 1994 Edition of NQA-1, ``Quality Assurance Requirements for Nuclear
Facility Applications,'' when using the 2006 Addenda of Section III of
the ASME B&PV Code and later editions and addenda. The reference to
ASME NQA-1 in Article 4000 of the ASME B&PV Code, Section III was
updated to a later edition of NQA-1 in the 2006 Addenda. NCA-4110(b)
was revised to require that the N-Type Certificate Holders comply with
the Basic Requirements and Supplements of the ASME NQA-1-1994 Edition.
Previous editions/addenda of the ASME B&PV Code, Section III referenced
earlier editions and addenda of ASME NQA-1. There are no significant
differences between of NQA-1-1994 Edition and the editions and addenda
of NQA-1 currently referenced in the regulation. The NRC has reviewed
and found the changes to Subsection NCA that reference the 1994 Edition
of NQA-1 to be acceptable.
[[Page 36252]]
10 CFR 50.55a(b)(1)(vii) Capacity Certification and Demonstration of
Function of Incompressible-Fluid Pressure-Relief Valves
The NRC is amending Sec. 50.55a(b)(1) to add a new paragraph
(b)(1)(vii) to modify the requirements in Subsection NB of the ASME
B&PV Code, Section III, for certifying the capacity of incompressible-
fluid, pressure-relief valves when the testing facility has less than
the full range of pressure capability necessary for achieving valve
set-pressure conditions during the testing. The NRC has identified no
issues with performing tests at less than the highest value of the set-
pressure range for incompressible-fluid, pressure-relief valves and
finds these new requirements for Class 2 and 3 components acceptable as
described in paragraphs NC-7742 and ND-7742. However, the NRC has
identified words that were inadvertently left out of the Code during
the final printing of paragraph NB-7742 for Class 1 components. The
parallel structure of the counterpart paragraphs (NC-7742 and ND-7742)
reveal that the words ``for the design and the maximum set pressure''
are missing from paragraph NB-7742(a)(2). Without these words,
paragraph NB-7742(a)(2) is confusing, illogical, and could lead to a
non-conservative interpretation of the required test pressure for the
new Class 1 incompressible-fluid, pressure-relief valve designs. For
these reasons, the final rule includes a condition in paragraph
(b)(1)(vii) allowing use of paragraph NB-7742 when the corrected
language intended by the Code is used.
ASME B&PV Code, Section XI
The regulations in Sec. 50.55a(b)(2) incorporate by reference ASME
B&PV Code, Section XI, 1970 Edition through the 1976 Winter Addenda;
and the 1977 Edition (Division 1) through the 2004 Addenda (Division
1), subject to the conditions identified in Sec. 50.55a(b)(2)(i)
through (b)(2)(xxvii). The NRC is amending the introductory text to
Sec. 50.55a(b)(2) to incorporate by reference the 2005 Addenda
(Division 1) through the 2008 Addenda (Division 1) of the ASME B&PV
Code, Section XI, clarify the wording, and remove or revise some of the
conditions as explained in this document.
The question has arisen in the past of whether Appendices of the
ASME B&PV Code, Section XI, are NRC requirements. The NRC is clarifying
in this section how the regulations in 10 CFR 50.55a apply to the
Section XI subsections and appendices. This discussion sets forth the
NRC's views regarding the applicable NRC requirements, clarifies which
portions of Section XI are approved for use by applicants and
licensees, identifies which portions of Section XI are NRC
requirements, and identifies which portions of Section XI are not
covered by the regulations in 10 CFR 50.55a.
First, it should be noted that in 10 CFR 50.55a, the NRC mandates
in 10 CFR 50.55a(g)(4) that throughout the service life of a boiling or
pressurized water-cooled nuclear power facility, components (including
supports) which are classified Class 1, 2, 3, MC and CC meet the
requirements of Section XI (with some exceptions). Specifically, within
Section XI, Subsection IWB provides the requirements for Class 1
components, Subsection IWC provides the requirements for Class 2
components, Subsection IWD provides the requirements for Class 3
components, Subsection IWE provides the requirements for Class MC
components, and Subsection IWL provides the requirements for Class CC
components. The NRC considers the rules of Subsection IWA and Section
XI Mandatory Appendices to be mandated as well, because the language in
IWA and the Mandatory Appendices covers general requirements that could
apply to the inservice inspection of Class 1, 2, 3, MC and CC
components.
The NRC is clarifying that the Section XI non-mandatory appendices
which are incorporated by reference into 10 CFR 50.55a are approved for
use, but are not mandated. The non-mandatory appendices may be used by
applicants and licensees of nuclear power plants (subject to the
conditions in 10 CFR 50.55a(b)(2)).
Introductory Text of 10 CFR 50.55a(b)(2)
The NRC is amending the introductory text of Sec. 50.55a(b)(2) to
clarify that references to Section XI refer to Section XI of the ASME
Boiler and Pressure Vessel Code.
10 CFR 50.55a(b)(2)(i) Limitations on Specific Editions and Addenda
The NRC is amending Sec. 50.55a(b)(2) to remove Sec.
50.55a(b)(2)(i) from the regulations and is designating that paragraph
as ``Reserved.'' This paragraph specified which addenda may be used
when applying the 1974 and 1977 Editions of Section XI of the ASME B&PV
Code. Section 50.55a(g)(4)(ii) requires that licensees' successive 120-
month inspection intervals comply with the requirements of the latest
edition and addenda of the code incorporated by reference in Sec.
50.55a(b)(2). Subsequently, licensees are no longer using these older
editions (1974 and 1977 Editions) and addenda of the ASME B&PV Code,
and therefore the NRC removed this paragraph.
10 CFR 50.55a(b)(2)(iii) Steam Generator Tubing
The NRC is amending Sec. 50.55a(b)(2) to remove Sec.
50.55a(b)(2)(iii) from the regulations and is designating that
paragraph as ``Reserved.'' The current regulations in Sec.
50.55a(b)(2)(iii) state that if the technical specifications of a
nuclear power plant include surveillance requirements for steam
generators different than those in Section XI, Article IWB-2000, the
ISI program of steam generator tubing is governed by the requirements
in the technical specifications. The 1989 Edition through the 2008
Addenda of Section XI IWB-2413, ``Inspection Program for Steam
Generator Tubing,'' state that ``the examinations shall be governed by
the plant Technical Specification.'' Because the condition in Sec.
50.55a(b)(2)(iii) is redundant to the 1989 Edition through the 2008
Addenda of Section XI, the NRC is removing this condition.
10 CFR 50.55a(b)(2)(iv) Pressure-Retaining Welds in ASME Code Class 2
Piping
The NRC is amending Sec. 50.55a(b)(2) to remove Sec.
50.55a(b)(2)(iv) from the regulations and is designating that paragraph
as ``Reserved.'' This paragraph states how to select appropriate Code
Class 2 pipe welds in residual heat removal systems, emergency core
cooling systems, and containment heat removal systems when applying
editions and addenda up to the 1983 Edition through the Summer 1983
Addenda of Section XI of the ASME B&PV Code. Section 50.55a(g)(4)(ii)
requires that licensee's successive 120-month inspection intervals
comply with the requirements of the latest edition and addenda of the
code incorporated by reference in Sec. 50.55a(b)(2). Subsequently,
licensees are no longer using these older editions and addenda of the
code (editions and addenda up to the 1983 Edition through the Summer
1983 Addenda of Section XI) and, therefore, the NRC is removing Sec.
50.55a(b)(2)(iv).
10 CFR 50.55a(b)(2)(v) Evaluation Procedure and Acceptance Criteria for
Austenitic Piping
The NRC is amending Sec. 50.55a(b)(2) to remove Sec.
50.55a(b)(2)(v) from the regulations and is designating that paragraph
as ``Reserved.'' This paragraph deals with evaluation procedures and
acceptance criteria for austenitic piping when applying the
[[Page 36253]]
Winter 1983 Addenda and the Winter 1984 Addenda of Section XI. Section
50.55a(g)(4)(ii) requires that licensees' successive 120-month
inspection intervals comply with the requirements of the latest edition
and addenda of the code incorporated by reference in Sec.
50.55a(b)(2). Subsequently, licensees are no longer using these older
editions and addenda of the code (editions and addenda up to the 1983
Edition through the Summer 1983 Addenda of Section XI), and therefore,
the NRC is removing Sec. 50.55a(b)(2)(v).
10 CFR 50.55a(b)(2)(vi) Effective Edition and Addenda of Subsection IWE
and Subsection IWL, Section XI
The NRC is amending Sec. 50.55a(b)(2)(vi) to stipulate the
editions and addenda of Subsection IWE and Subsection IWL of Section XI
of the ASME B&PV Code which are approved for use when licensees are
implementing the initial 120-month inspection interval for containment
inservice inspection requirements found in Section XI of the Code. The
final rule also requires that the use of these applicable editions and
addenda is subject to the conditions found in Sec. 50.55a(b)(2)(viii)
and (b)(2)(ix) for Subsection IWL and Subsection IWE, respectively.
Additionally, the NRC is amending Sec. 50.55a(b)(2)(vi) to change the
words ``modified and supplemented'' to ``conditioned'' for
clarification.
10 CFR 50.55a(b)(2)(viii) Examination of Concrete Containments
This paragraph stipulates the conditions that apply to the
inservice examination of concrete containments using Subsection IWL of
various editions and addenda of the ASME B&PV Code, Section XI,
incorporated by reference in Sec. 50.55a(b)(2). The regulations, in
part, require that licensees applying Subsection IWL, 2001 Edition
through the 2004 Edition shall apply the conditions in Sec.
50.55a(b)(2)(viii)(E) through (b)(2)(viii)(G). The NRC is amending
Sec. 50.55a(b)(2)(viii) to remove the conditions in Sec.
50.55a(b)(2)(viii)(F) and (b)(2)(viii)(G) in the final rule when
applying Subsection IWL of the 2007 Edition with 2008 Addenda of the
ASME B&PV Code, Section XI because the intent of these conditions has
been incorporated into the 2007 Edition with the 2008 Addenda of the
ASME B&PV Code, as explained in this document. Accordingly, the final
rule requires that licensees applying Subsection IWL, 2007 Edition with
the 2008 Addenda shall apply only the condition in Sec.
50.55a(b)(2)(viii)(E). Further, in the final rule, the conditions in
Sec. 50.55a(b)(2)(viii)(E) through (b)(2)(viii)(G) remain applicable
to licensees applying Subsection IWL, 2004 Edition through the 2006
Addenda.
The condition in Sec. 50.55a(b)(2)(viii)(F) relates to
qualification of personnel that examine containment concrete surfaces
and tendon hardware, wires, or strands. This condition states that
personnel that examine containment concrete surfaces and tendon
hardware, wires, or strands must meet the qualification provisions in
IWA-2300, and that the ``owner-defined'' personnel qualification
provisions in IWL-2310(d) are not approved for use. IWA-2300 stipulates
qualification provisions for personnel performing nondestructive
examination, including VT-1, VT-2, and VT-3 visual examinations.
Paragraph IWA-2312(c) requires training, qualification, and
certification of visual examination personnel to comply with the
requirements of Appendix VI of the Code, which makes reference to ANSI/
ASNT CP-189, and allows for limited certification (for personnel who
are restricted to performing examinations of limited or specific scope,
i.e., limited operations or limited techniques) per IWA-2350.
In Subsection IWL of the 2007 Edition, the ASME revised paragraph
IWL-2100 to state, in part, that except as noted in IWL-2320, the
requirements of IWA-2300 do not apply. Also, the 2007 Edition deleted
subparagraphs IWL-2310(d) and IWL-2310(e), which allowed certain
requirements (i.e., requirements for personnel qualification and
requirements for visual examination of concrete and tendon anchorage
hardware, wires, or strands) to be owner-defined. Further, the 2007
Edition with 2008 Addenda added a new paragraph IWL-2320 ``Personnel
Qualifications'' and re-designated the former IWL-2320 ``Responsible
Engineer'' as IWL-2330 ``Responsible Engineer.''
The new paragraph IWL-2320 stipulates specific plant experience,
training, written and practical examination and frequency of
administration to demonstrate training proficiency, and vision test
requirements for qualification of personnel approved by the Responsible
Engineer for performing general or detailed visual examinations of
structural concrete, reinforcing steel and post-tensioning system
components (i.e., wires, strands, anchorage hardware, corrosion
protection medium and free water) of Class CC containments. The
provision requires documentation of qualification requirements in the
Employer's written practice. The Responsible Engineer is responsible
for approval, instruction and training of personnel performing general
and detailed visual examinations. The new provision also provided the
requisite detailed requirements for the instruction material to be used
to qualify personnel performing IWL inspections. Specifically, the
addition included requirements for preservice and inservice inspections
for concrete (references American Concrete Institute 201.1R),
reinforcing steel, and post-tensioning items such as wires, strands,
anchorage hardware, corrosion protection medium, and free water. Thus,
the qualification requirements adequately include the areas and extent
of required plant experience, instructional topics for class room
training in IWL requirements and plant-specific IWL visual examination
procedures, and require the vision test requirements of IWA-2321. The
new paragraph IWL-2320, ``Personnel Qualifications,'' details specific
guidance for personnel qualification for containment concrete and
reinforcing steel and post-tensioning system visual inspections that
provide an acceptable level of quality and safety similar to the
requirements in IWA-2300 and therefore, addressed the intent of the
conditions in Sec. 50.55a(b)(2)(viii)(F) of the current regulations.
Therefore, the condition in Sec. 50.55a(b)(2)(viii)(F) is not required
to be applied for licensees using Subsection IWL, 2007 Edition with the
2008 Addenda. It is noted that the NRC's acceptance of the new code
provision IWL-2320, ``Personnel Qualifications,'' is based on paragraph
IWL-2320 of the 2007 Edition as supplemented by the addition by errata
in the 2008 addenda.
The condition in Sec. 50.55a(b)(2)(viii)(G) of the final rule
requires that corrosion protection material be restored following
concrete containment post-tensioning system repair and replacement
activities in accordance with the quality assurance program
requirements specified in IWA-1400.'' In the 2007 Edition of Subsection
IWL, the following revisions were made related to corrosion protection
medium for post-tensioning systems:
1. The revised paragraph IWL-4110 added footnote 1 which states
that the corrosion protection medium is exempt from the requirements of
IWL-4000. However, the corrosion protection medium must be restored in
accordance with IWL-2526 following concrete containment post-tensioning
system repair/replacement activities.
[[Page 36254]]
2. The revised Line Item L2.40 ``Corrosion Protection Medium'' of
Table IWL-2500-1 added reference to paragraph IWL-2526 in the columns
for Test or Examination Requirement, Test or Examination Method, and
Extent of Examination.
3. In the revised paragraph IWL-2526, subparagraph (b) requires
that following the completion of tests and examinations required by
Examination Category L-B, Items L2.10, L.2.20, and L2.30, the corrosion
protection medium must be replaced to ensure sufficient coverage of
anchorage hardware, wires, and strands. The total amount replaced in
each tendon sheath must be recorded and differences between amount
removed and amount replaced must be documented.
4. In the revised paragraph IWL-2526, subparagraph (d) requires
that the Responsible Engineer specify the method for corrosion
protection medium.
With the understanding that the Responsible Engineer (who per IWL-
2320 is a Registered Professional Engineer) will ensure that the
corrosion protection medium is restored in accordance with the
applicable Quality Assurance Program, the revised paragraphs IWL-
4110(b)(3) [with footnote 1] and IWL-2526, and revised line item L2.40
in Table IWL-2500-1 of Subsection IWL, 2007 Edition through the 2008
Addenda adequately incorporated the intent of the condition in Sec.
50.55a(b)(2)(viii)(G) of the current regulations and is acceptable to
the NRC. Therefore, the condition in Sec. 50.55a(b)(2)(viii)(G) is not
required to be applied for licensees using Subsection IWL, 2007 Edition
through the 2008 Addenda.
10 CFR 50.55a(b)(2)(ix) Examination of Metal Containments and the
Liners of Concrete Containments
This paragraph stipulates the conditions that apply to the
inservice examination of metal containments and liners of concrete
containments using Subsection IWE of various editions and addenda of
the ASME B&PV Code, Section XI, incorporated by reference in Sec.
50.55a(b)(2). As a result of public comments, the NRC is amending Sec.
50.55a(b)(2)(ix)(A) to divide the existing condition in Sec.
50.55a(b)(2)(ix)(A) into paragraphs (b)(2)(ix)(A)(1) and
(b)(2)(ix)(A)(2). The NRC is removing the conditions in Sec.
50.55a(b)(2)(ix)(A)(1), (b)(2)(ix)(F), (b)(2)(ix)(G), (b)(2)(ix)(H) and
(b)(2)(ix)(I) when applying the 2004 Edition with 2006 Addenda through
the 2007 Edition with 2008 Addenda of the ASME Code, Section XI because
these conditions have now been incorporated into the Code. The NRC is
also removing the condition in Sec. 50.55a(b)(2)(ix)(I) when applying
the 2004 Edition, up to and including, the 2005 Addenda. Furthermore,
the NRC is also amending Sec. 50.55a(b)(2)(ix) to add a new condition
as Sec. 50.55a(b)(2)(ix)(J) on the use of Article IWE-5000 of
Subsection IWE when applying the 2007 Edition, up to and including the
2008 Addenda of the ASME Code, Section XI. These changes are further
explained in this document.
The current regulations, in part, require that licensees applying
Subsection IWE, 1998 Edition through the 2004 Edition apply the
conditions in Sec. 50.55a(b)(2)(ix)(A), (b)(2)(ix)(B), and
(b)(2)(ix)(F) through (b)(2)(ix)(I). In the final rule, the conditions
in Sec. 50.55a(b)(2)(ix)(F) through (b)(2)(ix)(I) remain applicable to
licensees applying Subsection IWL, 1998 Edition through the 2001
Edition with the 2003 Addenda. As a minor correction to the current
regulations, the final rule requires that licensees applying Subsection
IWE of the 2004 Edition through the 2005 Addenda of the ASME B&PV Code,
satisfy the requirements of Sec. 50.55a(b)(2)(ix)(A), (b)(2)(ix)(B),
and (b)(2)(ix)(F) through (b)(2)(ix)(H). This correction is being made
since paragraph IWE-3511.3 of the 2004 Edition of the ASME B&PV Code
incorporated the condition in Sec. 50.55a(b)(2)(ix)(I), which requires
that the ultrasonic examination acceptance standard specified in IWE-
3511.3 for Class MC pressure-retaining components must also be applied
to metallic liners of Class CC pressure-retaining components. Further,
the final rule requires that licensees applying Subsection IWE, 2004
Edition with the 2006 Addenda through the latest edition and addenda
incorporated by reference in Sec. 50.55a(b)(2) satisfy the
requirements of Sec. 50.55a(b)(2)(ix)(A) and (b)(2)(ix)(B). This is
because the intent of the conditions in Sec. 50.55a(b)(2)(ix)(F)
through (b)(2)(ix)(H) were incorporated into Subsection IWE, 2004
Edition with the 2006 addenda, and the condition Sec.
50.55a(b)(2)(ix)(I) was incorporated into Subsection IWE, 2004 Edition,
as explained in this document.
The condition in Sec. 50.55a(b)(2)(ix)(F) of the final rule
requires that VT-1 and VT-3 examinations be conducted in accordance
with IWA-2200. Personnel conducting examinations in accordance with the
VT-1 or VT-3 examination method must be qualified in accordance with
IWA-2300, and the ``owner-defined'' personnel qualification provisions
in IWE-2330(a) for personnel that conduct VT-1 and VT-3 examinations
are not approved for use. This condition defines the code provision
(IWA-2200) and personnel qualification (IWA-2300) requirements for
personnel performing visual examinations by the VT-1 or VT-3 method, as
specified in the conditions in Sec. 50.55a(b)(2)(ix)(G) and
(b)(2)(ix)(H) of the rule. The condition does not allow use of the
``owner-defined'' personnel qualification provisions in IWA-2330(a) for
personnel that conduct VT-1 and VT-3 examinations. The revised code
provision in IWE-2330(a) of the 2006 Addenda requires that personnel
performing VT-1 and VT-3 visual examinations shall meet the
qualification requirements of IWA-2300. The revised code provision in
IWL-2100 of the 2006 Addenda states that IWA-2000 applies with the
exception that IWA-2210 and IWA-2300 do not apply to general visual
examination only (except as required by 2330(b) for vision test
requirements). Therefore, the code provisions in IWA-2200 and IWA-2300
will apply to VT-1 and VT-3 examinations. Thus, the revised code
provisions in IWE-2330(a) and IWE-2100 of the 2006 through 2008 Addenda
fully incorporates the condition in Sec. 50.55a(b)(2)(ix)(F).
Therefore, the condition in Sec. 50.55a(b)(2)(ix)(F) is not required
to be applied for licensees using Subsection IWE, 2004 Edition with the
2006 Addenda and the 2007 Edition through the 2008 Addenda.
The condition in Sec. 50.55a(b)(2)(ix)(G) of the final rule
requires that the VT-3 examination method be used to conduct the
examinations in Items E1.12 and E1.20 of Table IWE 2500-1, and the VT-1
examination method be used to conduct the examination in Item E4.11 of
Table IWE-2500-1. An examination of the pressure-retaining bolted
connections in Item E1.11 of Table IWE-2500-1 using the VT-3
examination method must be conducted once each interval. The ``owner-
defined'' visual examination provisions in IWE-2310(a) are not approved
for use for VT-1 and VT-3 examinations. This condition, applicable in
the current regulations to the 1998 Edition through the 2004 Edition,
requires that the VT-3 and VT-1 examination methods be used in lieu of
the ``General Visual'' and ``Detailed Visual'' methods, respectively,
as specified in Table IWE-2500-1 for the Item Numbers listed in the
condition, and that the owner-defined visual examination provisions in
IWE-2310(a) cannot be used for VT-1 and VT-3 examinations. In the 2006
Addenda through the 2008 Addenda, Table IWE-2500-1 was revised to
change the examination method for Item
[[Page 36255]]
Numbers E1.12 and E1.20 to the VT-3 method and for Item E4.11 to the
VT-1 method. Also, a new Examination Category E-G was added for
pressure-retaining bolting with Item No. E8.10 which requires 100
percent of each bolted connection to be examined, using the VT-1 method
and the acceptance standard in the newly added paragraph IWE-3530, once
during each Inspection Interval with the connection assembled and
bolting in-place, provided the connection is not disassembled during
the interval, or in the disassembled configuration if the connection is
disassembled for any reason during the interval. This VT-1 examination,
which is more stringent than the VT-3 method specified in the
condition, is in addition to the general visual examination of 100
percent of the pressure-retaining bolted connections during each
inspection period required to be performed under Item No. E1.11 of
Table IWE-2500-1. Further, the revised IWE-2310 does not have any
owner-defined provisions for performing visual examinations including
VT-1 and VT-3 examinations. Thus, the provisions in the revised Table
IWE-2500-1 and the revised paragraph IWE-2310 addressed the intent of
the condition in Sec. 50.55a(b)(2)(ix)(G). Therefore, the condition in
Sec. 50.55a(b)(2)(ix)(G) is not required to be applied for licensees
using Subsection IWE, 2004 Edition with the 2006 Addenda and the 2007
Edition through the 2008 Addenda.
The condition in Sec. 50.55a(b)(2)(ix)(H) of the final rule
requires that containment bolted connections that are disassembled
during the scheduled performance of the examinations in Item E1.11 of
Table IWE-2500-1 be examined using the VT-3 examination method. Flaws
or degradation identified during the performance of a VT-3 examination
must be examined in accordance with the VT-1 examination method, and
the criteria in the material specification or IWB 3517.1 must be used
to evaluate containment bolting flaws or degradation. As an alternative
to performing VT-3 examinations of containment bolted connections that
are disassembled during the scheduled performance of Item E1.11, VT-3
examinations of containment bolted connections may be conducted
whenever containment bolted connections are disassembled for any
reason. The condition in Sec. 50.55a(b)(2)(ix)(H) is similar to the
condition for bolted connections in Sec. 50.55a(b)(2)(ix)(G), but
applies only to the examination of pressure-retaining bolted
connections that are disassembled. The condition requires flaws or
degradation identified during the VT-3 examination to be examined using
the VT-1 method. The NRC notes that the VT-1 (and not VT-3) examination
method is the method specified in the new Item E8.10 for pressure-
retaining bolted connections in the revised Table IWE-2500-1 in the
2006 Addenda through 2008 Addenda of the ASME B&PV Code. Further, the
acceptance standard for the VT-1 examination of pressure-retaining
bolting in the new paragraph IWE-3530 requires that the relevant
conditions, as defined in IWA-9000, and listed in IWB-3517.1, shall be
corrected or evaluated to meet the requirements of IWE-3122, prior to
continued service. Therefore, the new provision for pressure-retaining
bolting in Table IWE 2500-1, as discussed in this document, and the new
acceptance standard specified in IWE-3530, as discussed in this
document, fully addressed the intent of the condition in Sec.
50.55a(b)(2)(ix)(H). Therefore, the condition in Sec.
50.55a(b)(2)(ix)(H) is not required to be applied for licensees using
Subsection IWE, 2004 Edition with the 2006 Addenda and the 2007 Edition
through the 2008 Addenda.
The condition in Sec. 50.55a(b)(2)(ix)(I) of the rule requires
that the ultrasonic examination acceptance standard specified in IWE-
3511.3 for Class MC pressure-retaining components also be applied to
metallic liners of Class CC pressure-retaining components. This
condition requires that the acceptance standard in IWE-3511.3 also
apply to the metallic shell and penetration liners of Class CC
pressure-retaining components in the re-designated paragraph IWE-3522,
``Ultrasonic Examination,'' in the 2004 Edition through the 2007
Edition and 2008 Addenda. Therefore, the condition in Sec.
50.55a(b)(2)(ix)(I) is not required to be applied for licensees using
Subsection IWE, 2004 Edition through the 2007 Edition and the 2008
Addenda.
The revised paragraph IWE-2310 (IWE-2313 to be specific) and new
subparagraphs IWE-2420(c) and IWE-2500(d), in the 2006 Addenda through
the 2008 Addenda, address the condition in Sec. 50.55a(b)(2)(ix)(A) of
the final rule with regard to requiring evaluation of acceptability of
inaccessible areas when conditions exist in accessible areas that could
indicate the presence or result in degradation to such inaccessible
areas. However, the information specified in the condition to be
provided in the ISI Summary Report is not explicitly addressed in the
ASME B&PV Code. Therefore, based on a public comment, for expediency to
remove part of the condition for certain addenda, the NRC is dividing
the existing condition in 50.55a(b)(2)(ix)(A) into paragraphs
(b)(2)(ix)(A)(1) and (b)(2)(ix)(A)(2). The condition in Sec.
50.55a(b)(2)(ix)(A)(1) of the final rule, addressing the requirement
for evaluation of inaccessible areas, is not required to be applied for
licensees using Subsection IWE, 2006 Addenda through the 2008 Addenda.
However, the condition in Sec. 50.55a(b)(2)(ix)(A)(2), addressing the
information relative to evaluation of inaccessible areas to be provided
in the ISI Summary Report, is required to be applied for licensees
using the 2006 Addenda through the 2008 Addenda.
10 CFR 50.55a(b)(2)(ix)(J)
The NRC is amending Sec. 50.55a(b)(2)(ix) to add a new Sec.
50.55a(b)(2)(ix)(J) to place a condition on the use of Article IWE-
5000, ``System Pressure Tests,'' of Subsection IWE when applying the
2007 Edition up to and including the 2008 Addenda of the ASME Code,
Section XI, for Class MC pressure-retaining components. The revised
Article IWE-5000 does not make a distinction between ``major'' and
``minor'' modification (or repair/replacement) with regard to the type
of pneumatic leakage tests specified following repair/replacement
activities. The NRC notes that IWL-5210 provides a reasonable
quantitative definition of a repair/replacement activity, in terms of
meeting the design basis Construction Code requirements prior to and
during the repair/replacement activity, that is considered major for
Class CC containments and requiring a containment pressure test to be
conducted at the design basis accident pressure (Pa) that would
demonstrate structural integrity of the repaired containment. There is
no such definition provided in IWE-5000 for Class MC containments. IWE-
5000 (2007 Edition with 2008 Addenda) requires a pneumatic leakage test
to be performed following welding or brazing associated with repair or
replacement activities, prior to returning the component to service. It
also allows the test boundary for the pneumatic leak test to be limited
to the brazed joints and welds affected by the repair/replacement
activity, which is acceptable from the point of ensuring leak-tightness
of the locally repaired area. However, it allows a licensee the option
of only performing a local bubble test even for a ``major'' containment
modification or repair/replacement, which is not sufficient to provide
a verification of global structural integrity. Following ``major''
containment repair/replacement activities, it makes the
[[Page 36256]]
performance of the appropriate pneumatic leakage test (which is a Type
A test) in accordance with 10 CFR part 50, Appendix J, optional, which
is inconsistent with the NRC position and the provisions in 10 CFR part
50, Appendix J, paragraph IV.A, and hence the NRC is adding a new
condition in this rule. It is, and has been, the NRC's position that a
10 CFR part 50, Appendix J, Type A test must be performed following a
``major'' containment modification or repair/replacement, prior to
returning the containment to operation. This is because a ``major''
containment modification such as the replacement of a large penetration
or the creation of large construction opening(s) for replacement of
equipment such as steam generators, reactor vessel head, pressurizers,
etc., or other similar repair/replacement activity results in the
breach of the containment pressure boundary that invalidates the
periodic verification of structural and leak tight integrity provided
by the previous Type A test as required by the Containment Leakage Rate
Testing Program in 10 CFR part 50, Appendix J. Further, the breach of
pressure boundary of the magnitude resulting from a ``major''
containment modification has a global effect on containment structural
integrity and not a localized effect. Therefore, performing a Type A
test prior to returning to operation, is necessary to provide a
reasonable assurance and verification of both containment structural
integrity and leakage integrity following restoration of a breach in
the containment pressure boundary due to a ``major'' repair/replacement
activity. Thus, the new condition in Sec. 50.55a(b)(2)(ix)(J) of the
final rule requires the performance of Type A test following a
``major'' containment modification of a Class MC containment structure.
The new condition provides a general, qualitative definition of
what constitutes a ``major'' modification or repair/replacement
activity for containments consistent with what the NRC has historically
considered as major modifications. The new condition also requires
that, when applying IWE-5000, if a Type A, B or C test is performed in
accordance with 10 CFR part 50, Appendix J, the test pressure and
acceptance standard for the test shall also be in accordance with 10
CFR part 50, Appendix J. This is because the test pressure range in
IWE-5223.1 seems to apply even for Type B and Type C tests; and the
acceptance standard for leakage in IWE-5223.5 is based only on Section
V, Article 10, for any pneumatic leakage test performed when applying
IWE-5000 of the 2007 Edition up to and including the 2008 Addenda of
Section XI of the ASME Code. The requirement in the new condition for
performing a Type A test prior to returning to operation following a
major containment modification, is necessary to provide a reasonable
assurance and verification of both containment structural and leakage
integrity following restoration of a breach in the containment pressure
boundary due to the ``major'' repair/replacement activity of a Class MC
containment structure.
10 CFR 50.55a(b)(2)(xv) Appendix VIII Specimen Set and Qualification
Requirements
The NRC is amending Sec. 50.55a(b)(2)(xv) so the conditions in
that paragraph would not apply to the 2007 Edition through the 2008
Addenda of Section XI of the ASME B&PV Code. Section 50.55a(b)(2)(xv)
has conditions that may be used to modify Appendix VIII of Section XI,
1995 Edition through the 2001 Edition. The ASME Boiler and Pressure
Vessel Code Committees took action to address these conditions in the
2007 Edition of the Code and revised Appendix VIII to address the NRC's
concerns with specimen sets and qualification requirements. Therefore,
the final rule does not require these conditions when using the 2007
Edition through the 2008 Addenda of the ASME B&PV Code.
10 CFR 50.55a(b)(2)(xv)(A)(2)
The NRC is amending Sec. 50.55a(b)(2)(xv)(A)(2) to modify the
condition to allow for an add-on qualification for austenitic welds
with no austenitic base metal side to an existing Supplement 10
qualification.
10 CFR 50.55a(b)(2)(xvi) Appendix VIII Single-Side Ferritic Vessel and
Piping and Stainless Steel Piping Examinations
The NRC is amending Sec. 50.55a(b)(2)(xvi) to modify the condition
to only apply to those licensees using the 2006 Addenda and earlier
editions and addenda of ASME Section XI.
10 CFR 50.55a(b)(2)(xviii) Certification of NDE Personnel
The NRC is amending Sec. 50.55a(b)(2)(xviii)(B) so the current
condition in that paragraph would not apply to the 2007 Edition through
the 2008 Addenda of Section XI of the ASME B&PV Code. Section
50.55a(b)(2)(xviii)(B) limits the activities that can be performed by
NDE personnel certified in accordance with IWA-2316 of the 1998 Edition
through the 2004 Addenda of the ASME B&PV Code. These personnel are
limited to observing for leakage during system leakage and hydrostatic
tests conducted in accordance with IWA-5211(a) and (b). The ASME Boiler
and Pressure Vessel Code Committees took action to address this, and
modified IWA-2316 in the 2005 Addenda and the 2007 Edition to limit the
activities performed by personnel qualified in accordance with IWA-
2316. Therefore, the condition is not required when using the 2007
Edition through the 2008 Addenda. Accordingly, the NRC is amending
Sec. 50.55a(b)(2)(xviii)(B) for this condition not to apply when using
the 2007 Edition through the 2008 Addenda of the ASME B&PV Code.
The NRC is amending Sec. 50.55a(b)(2)(xviii)(C) so the condition
in that paragraph would not apply to the 2005 Addenda through the 2008
Addenda of Section XI of the ASME B&PV Code. This paragraph places
conditions on the qualification of VT-3 examination personnel certified
under paragraph IWA-2317 of the 1998 Edition through the 2004 Addenda.
The regulation requires the administering of an initial qualification
examination to demonstrate proficiency of this training, and
administering subsequent examinations on a 3-year interval. The ASME
Boiler and Pressure Vessel Code Committees took action to address this
condition and modified IWA-2317 in the 2005 Addenda of the ASME B&PV
Code to require a written examination for initial qualification and at
least every 3 years thereafter for VT-3 qualification. Therefore, the
final rule does not require this condition when using the 2005 Addenda
through the 2008 Addenda. The NRC is revising the wording of the
condition for clarity in the final rule based on public comment.
10 CFR 50.55a(b)(2)(xix) Substitution of Alternative Methods
The NRC is amending Sec. 50.55a(b)(2)(xix) so the conditions for
the substitution of alternative examination methods in that paragraph
would not apply when using the 2005 Addenda through the 2008 Addenda.
The conditions in Sec. 50.55a(b)(2)(xix) do not allow the use of
Section XI, IWA-2240 of the 1998 Edition through the 2004 Edition of
the ASME B&PV Code. These conditions also do not allow the use of IWA-
4520(c) of the 1997 Addenda through the 2004 Edition of Section XI of
the ASME B&PV Code. In 2005, the ASME Boiler and Pressure Vessel Code
Committees took action to address these conditions and modified IWA-
2240 and deleted IWA-4520(c) in the 2005 Addenda such that alternative
[[Page 36257]]
examination methods or newly developed techniques are not allowed to be
substituted for the methods specified in the construction code.
Therefore, these conditions are not required when using the 2005
Addenda through the 2008 Addenda.
The final rule also imposes the condition that paragraphs IWA-
4520(b)(2) and IWA-4521 of the 2007 Edition of Section XI, Division 1,
of the ASME B&PV Code, with the 2008 Addenda are not approved for use.
In the 2008 Addenda of Section XI of the ASME B&PV Code, the ASME added
new provisions in IWA 4520(b)(2) and IWA-4521 that allow the
substitution of ultrasonic examination (UT) for radiographic
examination (RT) specified in the Construction Code. Substitution of UT
for RT as addressed in paragraph IWA-4520(b)(2) of the ASME B&PV Code,
Section XI, for the repair/replacement welds in 2008 Addenda is of a
concern to the NRC because, depending on flaw type (i.e., volumetric or
planar) and orientation, UT and RT are not equally effective for flaw
detection and characterization. The NRC had originally identified
concerns relative to the calibration blocks to be used, and developed
two conditions that appear in RG 1.84, ``Design, Fabrication, and
Materials Code Case Acceptability, ASME Section III, Proposed Revision
34,'' October 2006.
RT is effective in detecting volumetric-type flaws (e.g., slag,
porosity, root concavity, and misalignment), planar type flaws with
large openings (e.g., lack of fusion and large cracks in high stressed
areas), and those flaws that are oriented in a plane parallel to the X-
ray beam. RT is effective in all materials common to the nuclear
industry for detecting the type of flaws generated during construction
due to workmanship issues and, therefore, ensures an acceptable level
of weld quality and safety at the time of construction. In contrast, UT
is most effective in detecting and sizing planar-type flaws associated
with inservice degradation due to, for example, fatigue or stress
corrosion cracking. Significant advances have recently been made
regarding the use of UT to detect flaws in cast stainless steel.
However, the ASME Code provisions addressing the inspection of cast
stainless steels are still under development and are, therefore, not
yet published for use. Finally, UT requires more surface scanning area
than RT to perform examinations.
To ensure that a UT technique would be capable of detecting typical
construction flaws, the NRC requires a licensee to demonstrate, through
performance-based ASME B&PV Code, Section XI, Appendix VIII-like
requirements, its capability of identifying the construction flaws
which are easily detected by RT. Performance-based qualifications
require demonstrations on mockups having flaws with realistic UT
responses and with a statistically sufficient number of representative
flaws and non-flawed volumes to establish procedure effectiveness and
personnel skill. The statistical approach to qualification has been
shown to improve the reliability of inspections, to improve the
probability of flaw detection, and to reduce the number of false calls.
The addition of only two or three construction flaws to a demonstration
is not sufficient to capture the variety of flaws common to
construction or to statistically evaluate procedure effectiveness and
personnel skills.
The NRC is concerned that using the second leg of the ultrasound
metal path (V-path) to achieve two direction scanning from only one
side of the weld may not be adequate in detecting construction flaws.
Single-side examinations have not been demonstrated for construction
flaws for any material. Single-side examinations of welds have been
successfully qualified for planar flaws in ferritic carbon and low
alloy steels but have not been reliably demonstrated for austenitic
stainless steel and nickel alloys.
Based on this information, the NRC concludes that the substitution
of UT for RT may not be adequate for detecting some construction flaws,
specifically in a single-V full penetration groove welds. Therefore,
substitution of UT for RT is not generically acceptable. This position
is consistent with the NRC's previous position with respect to the
review of ASME Code Case N-659-1, which is published in RG 1.193,
Revision 2, ``ASME Code Cases not Approved for Use.'' Accordingly, the
final rule imposes the condition that paragraphs IWA-4520(b)(2), and
IWA-4521 of the 2007 Edition of Section XI, Division 1, with 2008
Addenda are not approved for use.
10 CFR 50.55a(b)(2)(xxi) Table IWB-2500-1 Examination Requirements
The NRC is amending Sec. 50.55a(b)(2)(xxi) to remove and designate
as ``Reserved'' paragraph (b)(2)(xxi)(B) of this section because this
condition was not consistent with the NRC's unconditional approval of
Code Case N-652-1 in RG 1.147, Revision 15.
10 CFR 50.55a(b)(2)(xxiv) Incorporation of the Performance
Demonstration Initiative and Addition of Ultrasonic Examination
Criteria
The NRC is amending Sec. 50.55a(b)(2)(xxiv) not to apply the
condition when using the 2007 Edition through the 2008 Addenda. Section
50.55a(b)(2)(xxiv) prohibits the use of Appendix VIII, the supplements
of Appendix VIII and Article I-3000 of ASME B&PV Code, 2002 Addenda
through the 2004 Edition. In 2007, the ASME Boiler and Pressure Vessel
Code Committees took action to address this condition and modified
Appendix VIII and its Supplements in the 2007 Edition. Therefore, the
condition is not required when using the 2007 Edition through the 2008
Addenda, and the final rule eliminates this condition when using the
2007 Edition through the 2008 Addenda.
10 CFR 50.55a(b)(2)(xxv) Evaluation of Unanticipated Operating Events
The NRC had proposed a new Sec. 50.55a(b)(2)(xxv) to condition the
use of ASME B&PV Code, Section XI, Nonmandatory Appendix E,
``Evaluation of Unanticipated Operating Events.'' Based on the
Probabilistic Fracture Mechanics Analysis (PFMA) provided by
commenters, which used the Fracture Analysis of Vessels--Oak Ridge
(FAVOR) Code, the same tool used in the PFM analyses supporting the
final PTS rule (75 FR 13), the NRC concludes this condition is no
longer necessary. The PFMA showed that, based on a selected PWR and BWR
RPV having the highest RTNDT of the limiting RPV material
and a typical beltline fluence model, the PFMA generated a pressure
versus (T - RTNDT) curve for each of the two RPVs by setting
the CDF to 1E-6. The analytical results showed that the PFMA results
bounds the corresponding Appendix E curve for both the unanticipated
isothermal pressure events and the pressurized cool-down events. Since
(1) the PFMA methodology is consistent with the PTS rule's underlying
methodology, in which large flaws are considered statistically, and (2)
the resulting pressure versus (T - RTNDT) curve bounds the
corresponding curve based on the current Appendix E approach, the NRC
concludes that the current Appendix E methodology, without the NRC's
proposed condition, provides an appropriate conservative methodology
for evaluating RPV integrity following an unanticipated transient that
exceeds the operational limits in PWR plant operating procedures.
Therefore, the proposed condition placed on the use of
[[Page 36258]]
ASME Code, Section XI, Appendix E in the proposed rule is not included
in the final rule.
10 CFR 50.55a(b)(2)(xxvii) Removal of Insulation
The NRC is amending Sec. 50.55a(b)(2)(xxvii) to refer to IWA-5242
of the 2003 Addenda through the 2006 Addenda or IWA-5241 of the 2007
Edition through the 2008 Addenda of Section XI of the ASME B&PV Code
for performing VT-2 visual examination of insulated components in
systems borated for the purpose of controlling reactivity. The
regulations at Sec. 50.55a(b)(2)(xxvii) place specific requirements on
when insulation must be removed to visually examine insulated
components in accordance with IWA-5242. In the 2007 Edition of the ASME
B&PV Code, Section XI, paragraph IWA-5242 was deleted and these
requirements were included in paragraph IWA-5241.
10 CFR 50.55a(b)(2)(xxviii) Analysis of Flaws
The NRC is amending Sec. 50.55a(b)(2) to add a new paragraph
(b)(2)(xxviii) placing conditions on the use of Section XI,
Nonmandatory Appendix A, ``Analysis of Flaws.'' The final rule places a
condition on the use of Appendix A related to the fatigue crack growth
rate calculation for subsurface flaws defined in paragraph A-4300(b)(1)
when the ratio of the minimum cyclic stress to the maximum cyclic
stress (R) is less than zero. The fatigue crack growth rate, da/dN, is
defined as follows when using Equation (1) in paragraph A-4300(a) and
Equation (2) in paragraph A-4300(b)(1):
da/dN = 1.99 x 10-10 S ([Delta]KI)3.07
Where S is a scaling parameter and [Delta]KI is the range
of applied stress intensity factor.
S and [Delta]KI are defined in A-4300 (b)(1) of the ASME
B&PV Code, Section XI, Appendix A as follows:
For -2 <= R <= 0 and Kmax - Kmin <= 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI =
Kmax
For R < -2 and Kmax - Kmin <= 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI = (1
-R) Kmax/3
For R < 0 and Kmax - Kmin > 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI =
Kmax - Kmin
The above guidelines permit reduction of [Delta]KI from
the value of (Kmax - Kmin) when Kmax -
Kmin <= 1.12 [sigma]f [radic]([pi]a). This is
adequate if the material property [sigma]f is from test-
based data of the component material and if the geometry of the cracked
component can be modeled as an edge crack in a half plane, so that the
formula K = 1.12 [sigma] [radic]([pi]a) applies. In most ASME B&PV
Code, Section XI, Appendix A applications, test-based
[sigma]f is not available, and the generic value from the
ASME B&PV Code tabulations is used. Further, the geometry of a
subsurface flaw in a plate differs significantly from the model of an
edge crack in a half plane. Consequently, for the case where full
[Delta]KI should be used, the calculation in accordance with
ASME B&PV Code, Section XI, Appendix A may show that Kmax-
Kmin <= 1.12 [sigma]f [radic]([pi]a) and prompt a
wrongful reduction of [Delta]KI.
To address the use of the generic [sigma]f value instead
of the test-based value for the cracked component and the significant
difference between the cracked component geometry and the cracked test-
specimen geometry on which the criterion of 1.12 [sigma]f
[radic]([pi]a) is derived, the NRC revised the criterion of 1.12
[sigma]f [radic]([pi]a) to 0.8 times 1.12
[sigma]f [radic]([pi]a). By doing so, reduction of
[Delta]KI will not take place during the range of
Kmax - Kmin from 0.8 x 1.12 [sigma]f
[radic]([pi]a) to 1.12 [sigma]f [radic]([pi]a), erasing the
non-conservatism from the two sources mentioned above. Selection of a
multiplying factor of 0.8 is based on the following:
The 10 percent error that could be introduced for the
subsurface flaw configurations having membrane stress correction
factors less than 1.12 as indicated in Appendix A, Figure A-3310-1; and
Another 10-percent error that accounts for the uncertainty
in the [sigma]f value.
Applying the revised criterion of 0.8 times 1.12
[sigma]f [radic]([pi]a), results in the following condition
on the use of the fatigue crack growth rate calculation for subsurface
flaws defined in paragraph A-4300(b)(1) of Section XI, Nonmandatory
Appendix A when R is less than zero:
da/dN = 1.99 x 10-10 S ([Delta]KI)\3.07\
For R < 0, [Delta]KI depends on the crack depth, a, and
the flow stress, [sigma]f. The flow stress is defined by
[sigma]f = \1/2\ ([sigma]ys +
[sigma]ult), where [sigma]ys is the yield
strength and [sigma]ult is the ultimate tensile strength in
units ksi (MPa) and a is in units in. (mm).
For -2 <= R <= 0 and Kmax-Kmin <= 0.8 x 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI =
Kmax
For R < -2 and Kmax - Kmin <= 0.8 x 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI = (1
-R) Kmax/3
For R < 0 and Kmax-Kmin > 0.8 x 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI =
Kmax -Kmin
10 CFR 50.55a(b)(2)(xxix) Non-Mandatory Appendix R
The NRC is amending Sec. 50.55a(b)(2) to add a new condition in
Sec. 50.55a(b)(2)(xxix) to condition the use of ASME B&PV Code,
Section XI, Non-Mandatory Appendix R, ``Risk-Informed Inspection
Requirements of Piping.'' The final rule requires licensees to submit
an alternative in accordance with Sec. 50.55a(a)(3) and obtain NRC
authorization of the proposed alternative prior to implementing RI-ISI
programs under Appendix R. The 2004 Edition of the ASME B&PV Code,
Section XI, currently incorporated by reference in the regulations, did
not contain provisions for RI-ISI. The 2005 Addenda introduced Non-
Mandatory Appendix R into Section XI to provide requirements for the
RI-ISI of ASME B&PV Code Class 1, 2 and 3 piping. The addition of
Appendix R to Section XI was essentially the incorporation of ASME Code
Cases N-577 and N-578 into the ASME B&PV Code. The NRC determined that
ASME Code Cases N-577 and N-578 were unacceptable for use and are
currently listed in RG 1.193,``ASME Code Cases Not Approved for Use,''
Revision 2. Licensees have been implementing RI-ISI requirements for
piping as an alternative to the ASME B&PV Code, Section XI requirements
of Tables IWB-2500-1, IWC-2500-1 and IWD-2500-1 submitted in accordance
with Sec. 50.55a(a)(3). Adding a condition as Sec. 50.55a(b)(2)(xxvi)
that would require licensees to submit an alternative in accordance
with Sec. 50.55a(a)(3) and obtain NRC authorization of the proposed
alternative prior to implementing Appendix R, RI-ISI programs would
ensure that future RI-ISI programs continue to comply with RG 1.178,
``An Approach for Plant-Specific Risk-Informed Decisionmaking for
Inservice Inspection of Piping,'' RG1.200, ``An Approach for
Determining the Technical Adequacy of Probabilistic Risk Assessment
Results for Risk-Informed Activities,'' and NRC Standard Review Plan
3.9.8, ``Risk-Informed Inservice Inspection of Piping.''
ASME OM Code
The NRC is amending the introductory text in Sec. 50.55a(b)(3) to
incorporate by reference the 2005 and 2006 Addenda of the ASME OM Code
into 10 CFR 50.55a. The amendment to Sec. 50.55a(b)(3) also clarifies
that Subsections ISTA, ISTB, ISTC, and ISTD, Mandatory Appendices I and
II, and Nonmandatory Appendices A through H and J of the ASME OM Code
are incorporated by reference.
The conditions in Sec. 50.55a(b)(3)(i), (b)(3)(ii), and (b)(3)(iv)
continue to apply to the 2005 and 2006 Addenda because the earlier ASME
B&PV Code provisions that these regulations are based on were not
revised in the 2005 and 2006 Addenda of the ASME B&PV Code to address
the underlying issues
[[Page 36259]]
which led the NRC to impose the conditions on the ASME B&PV Code.
The NRC is amending the current requirements in Sec.
50.55a(b)(3)(v) to be consistent with the revised snubber ISI
provisions in the 2006 Addenda of the ASME B&PV Code, Section XI. To
accomplish this Sec. 50.55a(b)(3)(v) was divided into Sec.
50.55a(b)(3)(v)(A) and Sec. 50.55a(b)(3)(v)(B). Where Sec.
50.55a(b)(3)(v)(A) allows licensees using editions and addenda up to
the 2005 Addenda of ASME Section XI to optionally use Subsection ISTD,
ASME OM Code in place of the requirements for snubbers in Section XI.
Section 50.55a(b)(3)(v)(B) requires licensees using the 2006 Addenda
and later editions and addenda of Section XI to follow the requirements
of Subsection ISTD of the ASME OM Code for snubbers. Provisions for the
ISI of snubbers have been in Subsection ISTD since the ASME OM Code was
first issued in 1990.
10 CFR 50.55a(b)(3)(v) Subsection ISTD
Section 50.55a(b)(3)(v) allows licensees using editions and addenda
up to the 2004 Edition of the ASME B&PV Code, Section XI to comply
with, at their option, Subsection ISTD, ASME OM Code instead of the
requirements for snubbers in Section XI. If the licensee chooses to
comply with subsection ISTD, Sec. 50.55a(b)(3)(v) requires the snubber
preservice and inservice examinations to be performed using the VT-3
visual examination method. The NRC previously imposed this requirement
to ensure that an appropriate visual examination method was used for
the inspection of integral and non-integral snubber attachments, such
as lugs, bolting, and clamps when using Subsection ISTD of the ASME OM
Code. Section 50.55a(b)(3)(v)(A) allows licensees using editions and
addenda up to the 2005 Addenda of ASME B&PV Code, Section XI, to
optionally use Subsection ISTD, ASME OM Code in place of the
requirements for snubbers in Section XI and continues to invoke the VT-
3 requirement. This option does not apply when using the 2006 Addenda
and later editions and addenda of Section XI of the ASME B&PV Code.
Figure IWF-1300-1 was revised in the 2006 Addenda of Section XI to
clarify that integral and non-integral snubber attachments are in the
scope of Section XI. Therefore, the visual examination method specified
in the 2006 Addenda and later editions and addenda of Section XI
applies to the examination of integral and non-integral snubber
attachments. The NRC is thus amending Sec. 50.55a(b)(3)(v)(B) in the
final rule to require licensees using the 2006 Addenda and later
editions and addenda of Section XI to follow the requirements of
Subsection ISTD of the ASME OM Code for snubbers.
10 CFR 50.55a(b)(3)(vi) Exercise Interval for Manual Valves
The NRC is amending the current requirement for exercising manual
valves in Sec. 50.55a(b)(3)(vi). The final rule limits the current
requirement to the 1999 through 2005 Addenda of the ASME OM Code. The
current requirement is not applicable to the 2006 Addenda of the ASME
OM Code because the exercise interval in Subarticle ISTC-3540 for
manually operated valves was revised in this Addenda to make it the
same as the current requirement in Sec. 50.55a(b)(3)(vi).
Reactor Coolant Pressure Boundary, Quality Group B Components, and
Quality Group C Components
The NRC is amending Sec. 50.55a(c)(3), (d)(2), and (e)(2) to
replace ``but--'' with ``subject to the following conditions'' at the
end of the introductory text to each paragraph for clarity.
Inservice Testing Requirements
10 CFR 50.55a(f)(5)(iv) Requests for Relief
The NRC is amending Sec. 50.55a(f)(5)(iv) to clarify that
licensees are required to submit requests for relief based on
impracticality within 12 months after the expiration of the IST
interval for which relief is being sought. Section 50.55a(f)(5)(iv)
describes the licensee's responsibility to demonstrate to the
satisfaction of the NRC those items determined to be impractical and
discusses the timeframe for this determination. The final rule
clarifies Sec. 50.55a(f)(5)(iv) to more clearly articulate the
requirements for licensee action when compliance with certain code
requirements is determined to be impractical. Licensees have
interpreted the current language in Sec. 50.55a(f)(5)(iv) in a number
of ways, especially regarding NRC approval of their submittal within
the specified timeframe. Since the licensee has little or no control
over the timeliness of NRC action on their submittal, this
interpretation is problematic.
Inservice Inspection Requirements
Snubber Examination and Testing
Paragraphs (g)(2), (g)(3)(i), (g)(3)(ii), the introductory text of
paragraph (g)(4), and paragraphs (g)(4)(i) and (g)(4)(ii) of 10 CFR
50.55a reference Section XI of the ASME B&PV Code for component support
ISI (including snubber examination and testing provisions). Section
50.55a(b)(3)(v) allows licensees the option of complying with the
provisions in Subsection ISTD of the ASME OM Code for snubber
examination and testing in lieu of the ISI provisions for snubber
examination and testing in Article IWF-5000 of Section XI of the ASME
B&PV Code. However, Article IWF-5000 was deleted in the 2006 Addenda of
Section XI. Therefore, the NRC is amending Sec. 50.55a(b)(3)(v) to
require that licensees who use the 2006 Addenda and later editions and
addenda of Section XI must use the snubber examination and testing
provisions in Subsection ISTD of the ASME OM Code.
The NRC is amending Sec. 50.55a(g)(2), (g)(3)(i), (g)(3)(ii),
(g)(4)(i) and (g)(4)(ii) to require that licensees use the provisions
for preservice and inservice examination and testing of snubbers in
Subsection ISTD of the ASME OM Code when using the 2006 Addenda and
later edition of Section XI. Licensees may also use optional code cases
in RG 1.192 as approved by the NRC. The NRC is clarifying that
preservice examination may meet preservice examination requirements in
Section III as an alternative to preservice examination of Section XI.
The NRC is also amending the introductory text of Sec. 50.55a(g)(4) to
require that licensees using the ASME OM Code shall follow the
provisions in Subsection ISTD of the ASME OM Code for examination and
testing of snubbers instead of Article IWF-5000 of Section XI.
Provisions for examinations and tests of snubbers have been in Article
IWF-5000 since Subsection IWF was first issued in the Winter 1978
Addenda of Section XI, but Article IWF-5000 was deleted in the 2006
Addenda of Section XI. Because Article IWF-5000 was deleted, Subarticle
IWF-1220 in the 2006 Addenda of Section XI states that the examination
and testing requirements for snubbers are now outside the scope of
Section XI, and that the examination and test requirements for snubbers
can be found in Subsection ISTD of the ASME OM Code.
The NRC is also correcting an error to reinstate rule language
adopted in an August 2007 rulemaking (72 FR 49352; August 28, 2007),
which was deleted in a final rule (72 FR 71750; December 19, 2007)
whose publication closely followed the August 2007 rule. The statement
of considerations for the December 2007 rule did not acknowledge or
explain the reason for its removal of rule language which was adopted
four months earlier. The NRC believes that the December 2007 removal of
the rule language adopted in August 2007 was inadvertent, and the
[[Page 36260]]
result of the NRC's failure to revise the ``December 2007 rule language
to reflect the newly-adopted August 2007 rule language, before the
December 2007 rule was transmitted to the Federal Register for
publication.
This correction was not included in the May 4, 2010 proposed rule
(75 FR 24324) which preceded this final rule. The NRC finds, in
accordance with the Administrative Procedure Act, 5 U.S.C.
553(b)(3)(B), that good cause exists for adopting this correction
without notice in the Federal Register and an opportunity for public
comment.
The NRC is also amending Sec. 50.55a(g)(4)(ii) to provide at least
18 months for a specified set of licensees to update and begin
implementation of the 2007 Edition and 2008 Addenda versions of
Appendix VIII in their next inservice inspection interval. This set of
licensees are those whose next inservice inspection interval must begin
to be implemented during the period between 12 through 18 months after
the effective date of the final rule, and therefore would otherwise be
required to implement the 2007 Edition and 2008 Addenda versions of
Appendix VIII (providing them less than 18 months to comply with the
provisions of the 2007 Edition and 2008 Addenda versions of Appendix
VIII). For these licensees, the final rule permits a delay of 6 months
in the implementation of Appendix VIII only (i.e., these licensees will
still be required to update and implement the inservice inspection
program during the next inspection interval without delay). Other
licensees, whose next inservice inspection interval commences more than
18 months after the final date of the rule, will have sufficient time
to develop their programs for the next inservice inspection interval
and are not affected by this provision of the final rule.
10 CFR 50.55a(g)(4)(iii) Surface Examinations of High-Pressure Safety
Injection Systems
Section 50.55a(g)(4)(iii) currently gives licensees the option of
not performing surface examinations of high-pressure safety injection
systems as specified in Section XI, Table IWB-2500-1, ``Examination
Category B-J,'' Item Numbers B9.20, B9.21 and B9.22. Editions and
addenda of Section XI after the 1995 Edition have been modified, and
some of the Item Numbers have either changed or been deleted. The
surface examination requirement was removed from Table IWB-2500-1 in
the 2003 Addenda. Therefore, the final rule requires this condition to
apply to those licensees using Code editions and addenda prior to the
2003 Addenda.
10 CFR 50.55a(g)(5)(iii) and (g)(5)(iv) Inservice Inspection Requests
for Relief
Section 50.55a(g)(5)(iii) currently requires the licensee to notify
the NRC if conformance with certain code requirements are found to be
impractical and submit the information to support this determination to
the NRC. Section 50.55a(g)(5)(iv) currently requires that when
examination requirements of the code are determined to be impractical
by the licensee, that the basis for this determination must be
demonstrated to the satisfaction of the NRC not later than 12 months
after the expiration of the 120-month interval during which the
examination is determined to be impractical.
The final rule adds a sentence to Sec. 50.55a(g)(5)(iii) to
clarify that a request for relief must be submitted only after the
necessary examination has been attempted during a given ISI interval
and the ASME B&PV Code requirement determined to be impractical. In the
past, licensees have submitted requests under Sec. 50.55a(g)(5)(iii)
prior to performing the ASME B&PV Code examination in a given interval
based on limited examination coverage from previous ISI 10-year
intervals. The NRC believes that this is an inappropriate basis for a
determination of impracticality as new examination techniques are often
developed from one interval to the next, which could result in a
reasonable expectation of improved results. As a result, the NRC
believes that a licensee usually cannot make the determination that an
examination is indeed impractical without first attempting the
examination in the current ISI interval. In addition, if the NRC were
to grant relief prior to the component having been examined and the
results of the examination are less than stated in the request for
relief, the licensee would be required to resubmit the request for
relief to address the actual examination. This places an unnecessary
burden on the licensee and the NRC to review the same issue twice.
Accordingly, the final rule requires that the determination of
impracticality should be based on actual attempts to perform a
requirement, and that the relief request be submitted only after the
licensee has unsuccessfully attempted to perform the inspection in the
relevant inspection interval.
The final rule removes the requirement that the basis for the
licensee's determination that an examination is impractical be
demonstrated to the satisfaction of the NRC not later than 12 months
after the expiration of the 120-month interval during which the
examination is determined to be impractical. The current regulatory
language is problematic, inasmuch as the current regulations do not
explicitly require the licensee to submit a request for relief. This
interpretation of the current regulations was reflected in a comment
which stated that the current regulations may be interpreted to mean
that determinations of impracticality need not be submitted to the NRC
for approval (i.e., the licensee merely needed to be able to justify
the impracticality determination to the NRC's satisfaction if asked by
the NRC). In addition, the NRC recognizes that the licensee has little
or no control over the timeliness of NRC action on a licensee's request
for relief. Therefore, the final rule removes the current regulatory
language, and replaces it with language clearly stating that all
licensee determinations of impracticality must be submitted to the NRC
for approval.
The proposed rule would have required that a relief request under
Sec. 50.55a(g)(5)(iii) be submitted no later than 12 months after the
examination has been attempted in a given ISI interval and the licensee
has determined that the ASME Code requirement is impractical. Several
commenters stated that this proposed change, which differs from the
current requirement to submit a single relief request at the end of the
ISI interval, would place additional burden on licensees by increasing
the number of submittals licensees need to submit for code relief when
requirements are determined to be impractical. Rather than submitting
one request for relief at the end of the interval for all examination
requirements determined to be impractical throughout the 10-year
interval as currently allowed, licensees would be required to prepare a
submittal within 12 months of every examination that determined a
requirement was impractical. The NRC has determined that the
administrative burden on the licensee of preparing multiple relief
requests throughout the inspection interval, and the concomitant burden
on the NRC to act on those relief requests, does not appear to be
justified. Therefore, the final rule requires relief requests under
paragraph (g)(5)(iv) to be submitted no later than 12 months after the
expiration of the 120-month interval for which relief is sought.
10 CFR 50.55a(g)(6)(ii)(E) Reactor Coolant Pressure Boundary Visual
Inspections
The NRC is amending Sec. 50.55a(g)(6)(ii)(E)(1) through
(g)(6)(ii)(E)(3) to reference Revision 1 of Code Case N-722, and is
revising
[[Page 36261]]
footnote 1 to clarify requirements in that paragraph that pertain to
reactor coolant pressure boundary visual inspections. In the last
update to 10 CFR 50.55a, the NRC added new Sec. 50.55a(g)(6)(ii)(E),
requiring all PWR licensees to augment their ISI program by
implementing ASME Code Case N-722, subject to the conditions specified
in Sec. 50.55a(g)(6)(ii)(E)(2) through (g)(6)(ii)(E)(4). ASME Code
Case N-722-1, ``Additional Examinations for PWR Pressure Retaining
Welds in Class 1 Components Fabricated with Alloy 600/82/182 Materials
Section XI, Division 1,'' was published in Supplement 8 of the 2007
Edition of the ASME Boiler and Pressure Vessel Code Nuclear Code Case
book. Code Case N-722 has been updated to Revision 1 (N-722-1) and
contains one additional note indicating that visual examination of
Alloy 600/82/182 materials in flange seal leak-off lines is not
required. This change eliminates the need for licensees to submit
relief requests under Sec. 50.55a(3)(i) or 50.55a(a)(3)(ii) for flange
seal leak-off lines which are not normally exposed to a corrosive
environment and are inaccessible for visual examination. The NRC
believes that the likelihood of the flange seals being degraded is
relatively low. Therefore, the visual inspection of these flange leak-
off lines is not needed.
The current wording in the second sentence of footnote 1 to Sec.
50.55a(g)(6)(ii)(E) has generated some confusion, and has the
unintended consequence of some licensees believing that they need to
submit additional relief requests related to the percentage of
inspections to be completed during the current interval. The second
sentence in the current footnote was intended to provide guidance to
licensees for the distribution of weld inspections required by Code
Case N-722 throughout the remainder of a plant's current 10-year ISI
period after January 1, 2009. The intent was to require licensees to
distribute the population of weld inspections that are required only
once in a 10-year interval to be distributed over a licensee's current
interval and into the next interval in a manner such as that described
in IWA-2400 of the 1994 Addenda and later editions and addenda of
Section XI. Because the current wording was not specific, licensees
using editions and addenda of Section XI prior to the 1994 Addenda have
interpreted the regulation as requiring all the weld inspections
required by Code Case N-722 to be distributed over, and inspected
during, the remaining periods and outages in the current interval only,
which could be less than 10 years. The final rule revises footnote 1 to
Sec. 50.55a(g)(6)(ii)(E) to clarify this issue by directing licensees
to use the rules of IWB-2400 of the 1994 Addenda or later editions and
addenda of Section XI for scheduling weld inspections for Code Case N-
722-1 welds added in the middle of an interval.
10 CFR 50.55a(g)(6)(ii)(F) Examination Requirements for Class 1 Piping
and Nozzle Dissimilar-Metal Butt Welds
The NRC proposed adding a new Sec. 50.55a(g)(6)(ii)(F) to require
licensees to implement ASME Code Case N-770, ``Alternative Examination
Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel
Nozzle Butt Welds Fabricated with UNS N06082 or UNS W86182 Weld Filler
Material With or Without the Application of Listed Mitigation
Activities, Section XI, Division 1,'' with 15 conditions. Code Case N-
770 contains baseline and ISI requirements for unmitigated butt welds
fabricated with Alloy 82/182 material and preservice and ISI
requirements for mitigated butt welds fabricated with Alloy 82/182
material. On December 25, 2009, ASME approved Code Case N-770-1. The
ASME prepared Code Case N-770-1 to address comments on Code Case N-770
that NRC had provided to the ASME code committee. The NRC addressed
these comments in the proposed rule as conditions on implementation of
Code Case N-770.
The NRC reviewed the changes made in Code Case N-770-1 to determine
if it was appropriate for referencing in the new Sec.
50.55a(g)(6)(ii)(F) in lieu of Code Case N-770. The NRC concluded that
it was appropriate for referencing based on the following
considerations. Incorporation by reference of Code Case N-770-1 in lieu
of Code Case N-770 allows the NRC to remove eight and partially remove
one of the 15 conditions in the proposed rule. The NRC concluded that
removing these conditions significantly improves the rule. The basis
for removing or modifying each of these proposed conditions is
contained in the Analysis of Public Comments document (ADAMS Accession
No. ML110280240).
ASME Code Case N-770-1 has, in addition to changes to address
proposed NRC conditions, additional changes that made no significant
modification to the requirements from N-770. The NRC considers that the
editorial changes improve the usability of the rule. Only one technical
addition was made in Code Case N-770-1 that was not covered by the
proposed rule. The technical addition provides an alternative
examination volume for welds mitigated by optimized weld overlays. The
NRC concluded that, with the exception of the one technical addition,
Code Case N-770-1 was appropriate for referencing. Therefore, the NRC
is amending its regulations to incorporate Code Case N-770-1 by
reference instead of Code Case N-770. The NRC is adding a new condition
to the rule to preclude the use of the technical addition made to Code
Case N-770-1. The NRC has prepared a document, ``Review of Changes
Between American Society of Mechanical Engineers Boiler and Pressure
Vessel Code Cases N-770 and N-770-1 to Support 10 CFR 50.55a Final
Rule'' (ADAMS Accession No. ML111250292), setting forth the NRC's bases
for approval of all of the changes made in Code Case N-770-1.
In addition to the new condition discussed, the NRC is adding a
condition and is modifying two conditions from the proposed rule as a
result of public comments it received. Because a number of the proposed
conditions were not included, many of the remaining conditions in the
final rule have been renumbered.
Substitution of the Term ``Condition'' in 10 CFR 50.55a
The NRC is amending 10 CFR 50.55a to substitute the word
``condition(s)'' for the words ``limitation(s),'' ``modification(s),''
and ``provision(s)'' throughout 10 CFR 50.55a for consistency. The NRC
does not believe it necessary to distinguish among different types of
``caveats'' that it imposes on the use of the ASME Codes. Therefore,
the NRC will now use the term ``condition'' for clarity and
consistency.
IV. Paragraph-by-Paragraph Discussion
Quality Standards, ASME Codes and IEEE Standards, and Alternatives
10 CFR 50.55a(a)
The NRC is amending 10 CFR 50.55a to add the title ``Quality
standards, ASME Codes and IEEE standards, and alternatives'' to
paragraph (a).
Applicant/Licensee Proposed Alternatives to the Requirements of 10 CFR
50.55a
10 CFR 50.55a(a)(3)
The NRC is amending 10 CFR 50.55a(a)(3) to clarify that a proposed
alternative must be submitted to, and authorized by, the NRC prior to
an applicant or licensee implementing the alternative.
[[Page 36262]]
Standards Approved for Incorporation by Reference
10 CFR 50.55a(b) Standards Approved for Incorporation by Reference
The NRC is amending 10 CFR 50.55a(b) to add the title ``Standards
approved for incorporation by reference'' to paragraph (b).
The final rule also clarifies that non-mandatory appendices are
excluded from the ASME B&PV Code, Section III requirements that are
incorporated by reference into 10 CFR 50.55a, and clarifies that only
Division 1 requirements of Section III and Section XI are incorporated
by reference (not Division 2 and Division 3 requirements). The NRC is
also incorporating by reference ASME Code Case N-722-1 and N-770-1 into
10 CFR 50.55a.
ASME B&PV Code, Section III
10 CFR 50.55a(b)(1)
The NRC is amending paragraph (b)(1) to incorporate by reference
the 2005 Addenda (Division 1) through 2008 Addenda (Division 1) of
Section III of the ASME B&PV Code into 10 CFR 50.55a, subject to the
conditions outlined in modified paragraphs (b)(1)(i) through
50.55a(b)(1)(vi) and paragraph (b)(vii). The paragraph modification
also includes an editorial change to the references to Section III ASME
B&PV Code for clarification purposes. As a result, applicants and
licensees may use the 1974 Edition (Division 1) through the 2008
Addenda (Division 1) of Section III of the ASME B&PV Code subject to
the conditions contained within modified paragraphs (b)(1)(i) through
(b)(1)(vi) and new paragraph (b)(1)(vii).
10 CFR 50.55a(b)(1)(ii) Weld-Leg Dimensions
The NRC is applying the existing condition in paragraph (b)(1)(ii)
regarding stress indices used for weld stresses in piping design to the
comparable provisions in the ASME Code editions and addenda
incorporated by reference in this final rule. The paragraph
modification also includes the addition of a condition on the use of
paragraph NB-3683.4(c)(2) for applicants and licensees applying the
1989 Addenda through the latest edition and addenda of Section III of
the ASME B&PV Code incorporated by reference in this final rule. As a
result, this final rule prohibits applicants and licensees from using
Footnote 13 from the 2004 Edition through the 2008 Addenda of Section
III of the ASME B&PV Code to Figures NC-3673.2(b)-1 and ND-3673.2(b)-1
for welds with leg size less than 1.09 times the nominal pipe wall
thickness (tn). Also as a result, the use of paragraph NB-
3683.4(c)(2), is not allowed for applicants and licensees applying the
1989 Addenda through the latest edition and addenda of Section III of
the ASME B&PV Code incorporated by reference in this final rule.
10 CFR 50.55a(b)(1)(iii) Seismic Design of Piping
The NRC is amending paragraph (b)(1)(iii) to impose conditions on
the seismic design of piping when licensees use the latest editions and
addenda of the ASME B&PV Code, Section III, incorporated by reference
in modified paragraph (b). The paragraph is also amended to include an
editorial change to replace ``limitations and modifications'' with
``conditions'' and ``limitation'' with ``condition.'' The final rule
allows the use of Subarticles NB-3200, NB-3600, NC-3600, and ND-3600
for the seismic design of piping when applying editions and addenda, up
to and including the 1993 Addenda of the ASME B&PV Code, Section III,
subject to the condition in modified paragraph (b)(1)(ii). The amended
paragraph does not allow the use of Subarticles NB-3200, NB-3600, NC-
3600, and ND-3600 for the seismic design of piping when applying the
1994 Addenda through the 2005 Addenda of Section III of the ASME B&PV
Code except that Subarticle NB-3200 in the 2004 Edition through the
2008 Addenda of Section III of the ASME B&PV Code may be used by
applicants and licensees subject to the condition in new paragraph
(b)(1)(iii)(A) (see the following discussion on this new paragraph).
The final rule allows the use of Subarticles NB-3200, NB-3600, NC-3600,
and ND-3600 for the seismic design of piping when applying the 2006
Addenda through the 2008 Addenda of Section III of the ASME B&PV Code,
subject to the two new conditions in new paragraphs (b)(1)(iii)(A) and
(b)(1)(iii)(B).
10 CFR 50.55a(b)(1)(iii)(A)
The NRC is amending 10 CFR 50.55a(b)(1)(iii) to add a new paragraph
(b)(1)(iii)(A) which requires licensees and applicants using Note (1)
of Figure NB-3222-1 in Section III of the 2004 Edition up to and
including the 2008 Addenda of the ASME B&PV Code to include reversing
dynamic loads in calculating primary bending stresses, if consideration
of these loads is warranted by subparagraph NB-3223(b).
10 CFR 50.55a(b)(1)(iii)(B)
The NRC is amending 10 CFR 50.55a(b)(1)(iii) to add a new
paragraph(b)(1)(iii)(B) which imposes a condition on the use of
Subarticle NB-3600 of the ASME B&PV Code, Section III when applying the
2006 Addenda through the 2008 Addenda of Section III of the ASME B&PV
Code by requiring the material and Do/t requirements found
in NB-3656(b) to be adhered to for all Service Limits if the Service
Limits include reversing dynamic loads which are not required to be
combined with non-reversing dynamic loads, and the alternative rules
for reversing dynamic loads are used. As such, per NB-3656(b), the
final rule requires that licensee's adhere to a Do/t ratio
limitation requiring this ratio to be less than 40 for all Service
Limits when evaluating the seismic design of Class 1 piping. Paragraph
(b)(1)(iii) specifies both whether the condition applies and the
circumstances in which it applies.
10 CFR 50.55a(b)(1)(iv) Quality Assurance
The NRC is amending paragraph (b)(1)(iv) to allow the use of the
1994 Edition of NQA-1 when applying the 2006 Addenda and later editions
of the ASME B&PV Code, Section III, up to the 2008 Addenda. Previously
paragraph (b)(1)(iv) permitted the use of NQA-1 up to the 1992 Edition.
10 CFR 50.55a(b)(1)(vii) Capacity Certification and Demonstration of
Function of Incompressible-Fluid Pressure-Relief Valves
In the 2006 Addenda, new requirements were added to the ASME Code,
Section III, that have a parallel structure in paragraphs NB-7742, NC-
7742, and ND-7742 for Class 1, 2, and 3 incompressible-fluid, pressure
relief valves, respectively. These new paragraphs address new valve
designs having a range of possible sizes and set-pressure conditions.
The method described in these paragraphs for performing the tests and
evaluation data involves performing tests at less than the highest
value of the set-pressure range and establishing an incompressible
fluid flow coefficient of discharge that then allows extrapolation of
capacities to higher pressures. These new paragraphs address
circumstances in which a certified test facility lacks the fluid-
pressure capability at the necessary flow rate for testing a new,
incompressible-fluid, pressure-relief valve design. Due to a printing
error in the ASME Code for paragraph NB-7742(a)(2), some words were
omitted. The NRC is amending paragraph (b)(1)(vii) to add a condition
to allow use of NB-7742(a)(2) when the language intended to be included
in the Code is used.
[[Page 36263]]
ASME B&PV Code, Section XI
10 CFR 50.55a(b)(2)
The NRC is amending the introductory text to paragraph (b)(2) to
incorporate by reference only Subsections IWA, IWB, IWC, IWD, IWE, IWF,
IWL, Mandatory and Non-Mandatory Appendices, of the 2005 Addenda
through 2008 Addenda of Section XI of the ASME B&PV Code, with
conditions, into 10 CFR 50.55a. It is also amended to make clear that
references to Section XI are to Section XI of the ASME B&PV Code.
10 CFR 50.55a(b)(2)(i)
The NRC is deleting the requirements of paragraph (b)(2)(i), which
address limitations on specific editions and addenda, and is
designating the paragraph as ``Reserved.'' Licensees are no longer
using these older editions (1974 and 1977 Editions) and addenda of the
ASME B&PV Code.
10 CFR 50.55a(b)(2)(iii)
The NRC is deleting the requirements of paragraph (b)(2)(iii),
which address steam generator tubing, and is designating this paragraph
as ``Reserved.''
10 CFR 50.55a(b)(2)(iv)
The NRC is deleting the requirements of paragraph (b)(2)(iv), which
address pressure retaining welds in ASME Code Class 2 piping, and is
designating this paragraph as ``Reserved.''
10 CFR 50.55a(b)(2)(v)
The NRC is deleting the requirements of paragraph (b)(2)(v), which
address the evaluation procedures and acceptance criteria for
austenitic piping when applying the Winter 1983 Addenda and the Winter
1984 Addenda of Section XI, and is designating this paragraph as
``Reserved.''
10 CFR 50.55a(b)(2)(vi)
This paragraph addresses the pertinent editions and addenda of the
ASME B&PV Code for which licensees must utilize when implementing the
initial inservice inspection requirements for containment structures.
The NRC is amending paragraph (b)(2)(vi) to clarify that, in accordance
with the paragraph, licensees may use either the 1992 Edition with the
1992 Addenda or the 1995 Edition with the 1996 Addenda of Subsection
IWE and Subsection IWL of the ASME B&PV Code, Section XI, for the
initial 120-month inspection interval, subject to the conditions in
paragraphs (b)(2)(viii) and (b)(2)(ix), including the new condition
identified in paragraph (b)(2)(ix)(J). Following the initial 120-month
inspection interval, successive 120-month inspection interval updates
must be implemented in accordance with the provisions of paragraph
(g)(4)(ii).
10 CFR 50.55a(b)(2)(viii)
This paragraph, which addresses the inservice examination of
concrete containments in accordance with Subsection IWL of the ASME
B&PV Code, Section XI, is amended so that the conditions in paragraphs
(b)(2)(viii)(F) and (b)(2)(viii)(G) do not apply when using the 2007
Edition to the latest edition and addenda incorporated by reference
into Sec. 50.55a (currently the 2008 Addenda of the ASME B&PV Code).
10 CFR 50.55a(b)(2)(ix)
This paragraph addresses the examination of metal containments and
the liners of concrete containments in accordance with Subsection IWE
of the ASME B&PV Code, Section XI. The NRC is dividing the existing
condition in paragraph (b)(2)(ix)(A) into paragraphs (b)(2)(ix)(A)(1)
and (b)(2)(ix)(A)(2). The NRC is also amending the introductory text of
this paragraph so that the conditions in paragraphs (b)(2)(ix)(F),
(b)(2)(ix)(G), (b)(2)(ix)(H) and (b)(2)(ix)(I) do not apply when using
the 2004 Edition with 2006 Addenda through the 2007 Edition with 2008
Addenda of Subsection IWE of the ASME B&PV Code, Section XI. Also, the
NRC is amending the introductory text of this paragraph so that the
condition in paragraph (b)(2)(ix)(I) does not apply when using the 2004
Edition, up to and including the 2005 Addenda of Subsection IWE of the
ASME B&PV Code, Section XI.
10 CFR 50.55a(b)(2)(ix)(J)
The NRC is amending paragraph (b)(2)(ix) to add a new paragraph
(b)(2)(ix)(J) to address pressure testing requirements following major
modifications of Class MC containment structures when applying Article
IWE-5000, of Subsection IWE of the 2007 Edition to the latest edition
and addenda incorporated by reference into Sec. 50.55a (currently the
2008 Addenda of the ASME B&PV Code, Section XI).
10 CFR 50.55a(b)(2)(xv)
The NRC is amending the requirements in paragraph (b)(2)(xv), which
address Appendix VIII specimen set and qualification requirements, by
limiting the use of the provisions described in paragraphs
(b)(2)(xv)(A) through (b)(2)(xv)(M) to licensees using the B&PV Code
2001 Edition and earlier editions and addenda. Additionally, paragraph
(b)(2)(xv)(A)(2) is amended to allow a qualification for austenitic
welds with no austenitic base metal side to be added on to an existing
Supplement 10 qualification.
10 CFR 50.55a(b)(2)(xvi)
The NRC is amending the requirements in paragraph (b)(2)(xvi),
which address Appendix VIII single-sided ferritic-vessel and piping and
stainless steel piping examination, to limit the condition to those
licensees using the editions and addenda of ASME Section XI prior to
the 2007 Edition on Section VIII.
10 CFR 50.55a(b)(2)(xviii)(B)
The NRC is amending paragraph (b)(2)(xviii)(B), which addresses
certification of NDE personnel that observe leakage during system
leakage and hydrostatic testing, such that the condition would only
apply to editions and addenda prior to the 2007 Edition of Section XI.
10 CFR 50.55a(b)(2)(xviii)(C)
The NRC is amending paragraph (b)(2)(xviii)(C), which addresses
certification of NDE personnel, such that the current conditions on the
qualification of VT-3 examination personnel requiring initial
qualification examinations and subsequent examinations on a 3-year
interval would only apply to the editions and addenda prior to the 2005
Addenda of Section XI.
10 CFR 50.55a(b)(2)(xix)
The NRC is amending paragraph (b)(2)(xix), which addresses
substitution of alternative methods, so the current conditions for the
substitution of alternative examination methods in that paragraph would
not apply when using the 2005 Addenda through the 2008 Addenda. The
paragraph is also amended to impose the condition that paragraphs IWA-
4520(b)(2) and IWA-4521 of the 2007 Edition of Section XI, Division 1,
with 2008 Addenda, are not approved for use.
10 CFR 50.55a(b)(2)(xxi)
The NRC is deleting the requirements of paragraph (b)(2)(xxi)(B),
which addressed examination requirements for Examination Category B-G-
2, Item B7.80 bolting, and designating it as ``Reserved.'' This
condition was inconsistent with the NRC's unconditional approval of
Code Case N-652-1, ``Alternative Requirements to Categories B-G-1, B-G-
2, and C-D Bolting Examination Methods and Selection Criteria'' in RG
1.147, Revision 15.
[[Page 36264]]
10 CFR 50.55a(b)(2)(xxiv)
The NRC is amending the requirements in paragraph (b)(2)(xxiv),
which addresses incorporation of the performance demonstration
initiative and addition of ultrasonic examination criteria, so that the
current condition would not apply when using the 2007 Edition through
the 2008 Addenda of Section XI of the ASME B&PV Code.
10 CFR 50.55a(b)(2)(xxvii)
The NRC is amending the requirements in paragraph (b)(2)(xxvii),
which address removal of insulation, to add a condition to refer to
paragraph IWA-5241 instead of IWA-5242 for the 2007 Edition and later
addenda of Section XI of the ASME B&PV Code.
10 CFR 50.55a(b)(2)(xxviii)
The NRC is adding a new paragraph (b)(2)(xxviii), Analysis of
flaws, which conditions the use of the fatigue crack growth rate
calculation for subsurface flaws defined in paragraph A-4300(b)(1) of
Section XI, Nonmandatory Appendix A when the ratio of the minimum
cyclic stress to the maximum cyclic stress (R) is less than zero.
10 CFR 50.55a(b)(2)(xxix)
The NRC is adding a new paragraph (b)(2)(xxix), which conditions
the use of ASME B&PV Code, Section XI, Non-Mandatory Appendix R, to
require licensees to submit an alternative in accordance with paragraph
(a)(3) and obtain NRC authorization of the proposed alternative prior
to implementing Appendix R, RI-ISI programs.
ASME OM Code
10 CFR 50.55a(b)(3)
The NRC is amending the introductory text of paragraph (b)(3) to
require that the 2004 Edition with the 2005 and 2006 Addenda of the
ASME OM Code be used during the initial 120-month IST interval under
paragraph (f)(4)(i) and during mandatory 120-month IST program updates
under paragraph (f)(4)(ii). The amendment also allows users to
voluntarily update their IST programs to the 2004 Edition with the 2005
and 2006 Addenda of the ASME OM Code under paragraph (f)(4)(iv).
10 CFR 50.55a(b)(3)(v)
The NRC is amending paragraph (b)(3)(v) to require that the
provisions in Subsection ISTD of the ASME OM Code be used for the
inservice examination and testing of snubbers when using the 2006
Addenda and later editions and addenda of Section XI.
10 CFR 50.55a(b)(3)(vi)
The NRC is amending paragraph (b)(3)(vi) to require that the
current condition for exercising manual valves continue to apply when
using the 1999 through 2005 Addenda of the ASME OM Code. This condition
does not apply to the 2006 Addenda and later editions and addenda of
the ASME OM Code.
Reactor Coolant Pressure Boundary, Quality Group B Components and
Quality Group C Components
The NRC is amending paragraphs (c)(3), (d)(2), and (e)(2) to
replace ``but--'' with ``subject to the following conditions'' at the
end of the introductory text to the paragraphs for clarity.
Inservice Testing Requirements
10 CFR 50.55a(f)(5)(iv)
The NRC is amending paragraph (f)(5)(iv) to clarify that licensees
are required to submit requests for relief based on impracticality
within 12 months after the expiration of the IST interval for which
relief is being sought.
Inservice Inspection Requirements
10 CFR 50.55a(g)(2), (g)(3)(i), (g)(3)(ii), and the Introductory Text
of (g)(4)
The NRC is amending paragraphs (g)(2), (g)(3)(i), and (g)(3)(ii) to
require that the provisions in the ASME OM Code, and the optional ASME
code cases listed in RG 1.192, be used for the examination and testing
of snubbers. The NRC is amending the introductory text of paragraph
(g)(4) to require that licensees use the provisions in the ASME OM Code
for the examination and testing of snubbers.
10 CFR 50.55a(g)(4)(i)
The NRC is amending paragraph (g)(4)(i) to require that the
optional code cases listed in RG 1.192 be followed when using the ASME
OM Code. The NRC is also correcting an earlier error which deleted rule
language in this paragraph which is applicable to combined licenses
under 10 CFR part 52. The restored rule language makes clear that, for
combined license holders under 10 CFR part 52, the inservice
examinations for the initial 120-month inspection interval must comply
with the inservice examination requirements in the latest edition and
addenda of the Code approved by the NRC in Sec. 50.55a on the date 12
months before the date scheduled for initial loading of fuel under a
combined license under 10 CFR part 52, except as allowed--as with
operating licenses under 10 CFR part 50--under the remainder of
paragraph (g)(4)(i).
10 CFR 50.55a(g)(4)(ii)
The NRC is amending paragraph (g)(4)(ii) to allow the optional code
cases listed in RG 1.192 to be followed when using the ASME OM Code.
Paragraph (g)(4)(ii) is also amended to provide up to a 6-month delay
in the implementation of the 2007 Edition and 2008 Addenda provisions
of Appendix VIII for those licensees whose next inspection interval
must be implemented in the period between 12 through 18 months after
the effective date of the final rule. Other licensees, whose next
inservice inspection interval commences more than 18 months after the
final date of the rule, are not affected by this provision of the final
rule.
10 CFR 50.55a(g)(4)(iii)
The NRC is amending paragraph (g)(4)(iii) to provide the proper
references to Section XI, Table IWB-2500-1, ``Examination Category B-
J,'' Item Numbers B9.20, B9.21 and B9.22, and to limit the condition's
applicability to the editions and addenda prior to the 2003 Addenda of
Section XI.
10 CFR 50.55a(g)(5)(iii)
The NRC is amending paragraph (g)(5)(iii) by adding a sentence to
clarify that a request for relief must be submitted to the NRC only
after an examination has been attempted during a given ISI interval and
the ASME Code requirement determined to be impractical. These requests
for relief describing the determinations that the code requirement is
impractical must be submitted to the NRC no later than 12 months after
the expiration of the initial or subsequent 120-month inspection
interval for which relief is sought.
10 CFR 55a(g)(5)(iv)
The NRC is amending paragraph (g)(5)(iv) to clarify that licensees
are required to submit requests for relief based on impracticality no
later than 12 months after the end of the ISI interval for which relief
is being sought.
10 CFR 50.55a(g)(6)(ii)(E)(1) Through (g)(6)(ii)(E)(3)
The NRC is amending paragraphs (g)(6)(ii)(E)(1) through
(g)(6)(ii)(E)(3) by changing the requirement to implement Code Case N-
722 to a requirement to implement Code Case N-722-1.
10 CFR 50.55a(g)(6)(ii)(F)
The final rule incorporates ASME Code Case N-770-1 by reference in
paragraph (g)(6)(ii)(F)(1). The NRC is not including the following
proposed
[[Page 36265]]
conditions in this final rule, since they are addressed in Code Case N-
770-1: paragraphs (g)(6)(ii)(F)(5), (6), (8), (9), (10), (11), (13),
and (14). The NRC is not including part of the proposed condition in
paragraph (g)(6)(ii)(F)(7), since the part is addressed in Code Case N-
770-1. Because the NRC did not include these proposed conditions in the
final rule, the numbering of the conditions in the final rule differs
from that of the proposed rule.
Paragraph (g)(6)(ii)(F)(2) pertains to obtaining NRC approval prior
to reclassification of welds under the Inspection Items of Code Case N-
770. All mitigation techniques discussed in Code Case N-770, with the
exception of Mechanical Stress Improvement Process, are covered by
separate ASME Code Cases. These Code Cases are subject to approval by
the NRC. As ASME completes these mitigation Code Cases, the NRC will
review and approve them, if appropriate, possibly with conditions. The
NRC uses RG 1.147, which is incorporated by reference in 10 CFR 50.55a,
to endorse approved Code Cases for generic use. Based on the wording of
paragraph (g)(6)(ii)(F)(2), as the NRC endorses mitigation Code Cases
in the RG, the rule permits licensees to categorize mitigated welds in
the corresponding Inspection Items in Code Case N-770-1, without a
separate NRC review of the classification or reclassification. This
condition is unchanged from the proposed rule.
Paragraph (g)(6)(ii)(F)(3) pertains to the schedule for completing
baseline examinations. The final rule extends the timing for completing
baseline examinations. Previous examinations of these welds can be
credited for baseline examinations if they were performed using Section
XI, Appendix VIII requirements and met the Code required examination
volume for axial and circumferential flaws of essentially 100 percent.
For butt welds that received a MRP-139 examination that did not fully
meet Section XI, Appendix VIII requirements or achieve essentially 100
percent coverage, licensees can re-perform the baseline examination to
meet these requirements or obtain NRC authorization of alternative
examination requirements in accordance with 10 CFR 50.55a(a)(3)(i) or
(ii) by the end of next refueling outage that occurs after six months
from the effective date of the final rule. A licensee may choose to use
previous inspections of dissimilar metal butt welds performed under the
plant's ASME Code, Section XI, Inservice Inspection program to meet the
paragraph (g)(6)(ii)(F)(3) baseline requirement. This is acceptable
provided the previous inspection falls within the re-inspection period
for welds in ASME Code Case N-770-1, Table 1, Inspection Items A-1, A-
2, and B. Additionally, the NRC-approved alternative examination
coverage for these welds during the current 10-year inservice
inspection interval remain applicable. In all of these cases the
previously approved alternative will continue to apply for the duration
authorized by the NRC. In the final rule the NRC modified the proposed
condition to extend the timing for completing baseline examinations and
to address credit for previous baseline examinations.
Paragraph (g)(6)(ii)(F)(4) pertains to the requirement for
satisfying axial examination coverage of welds. The discussion for
paragraph (g)(6)(ii)(F)(4) contains guidance on satisfying the axial
examination coverage requirement during previous baseline examinations.
This condition is unchanged from the proposed rule.
Paragraph (g)(6)(ii)(F)(5) requires that all hot-leg temperature
welds in the Code Case N-770-1 Inspection Items G, H, J and K for
inlays and onlays be inspected each interval and specifies requirements
for sample inspection of cold leg temperature welds in these Inspection
Items. This condition prohibits sample inspection of hot leg
temperature welds in Inspection Items G, H, J, and K. This condition
was part of paragraph (g)(6)(ii)(F)(7) of the proposed rule. This part
of the condition is unchanged from the proposed rule.
Paragraph (g)(6)(ii)(F)(6) pertains to submitting reports to the
NRC for mitigated welds whose volumetric examination detects new flaws
or growth of existing flaws in the required examination volume. This
condition was included in paragraph (g)(6)(ii)(F)(12) of the proposed
rule. This condition is unchanged from the proposed rule.
Paragraph (g)(6)(ii)(F)(7) requires that the thickness of the inlay
or onlay be used as the thickness ``t'' when applying the acceptance
standards in ASME Section XI, IWB-3514, for planar flaws contained
within the inlay or onlay in Inspection Items G, H, J, and K. This
condition was included in paragraph (g)(6)(ii)(F)(15) of the proposed
rule. In the final rule paragraph (g)(6)(ii)(F)(7) is expanded to
clarify that for planar flaws in the balance of the dissimilar metal
weld examination volume, the thickness ``t'' in IWB-3514 is the
combined thickness of the inlay or onlay and the dissimilar metal weld.
Paragraph (g)(6)(ii)(F)(8) prohibits sample inspection of welds
mitigated by optimized weld overlays in Inspection Items D and E. This
condition was included in paragraph (g)(6)(ii)(F)(16) of the proposed
rule. This condition is unchanged from the proposed rule.
Paragraph (g)(6)(ii)(F)(9) is a new condition as a result of public
comments. This condition removes the requirement of Code Case N-770-1
to spread the initial examinations of the Inspection Item D welds
mitigated in the same inspection period throughout years 3 through 10
following application of stress improvement. For the extent and
frequency of examination in Table 1, the condition requires that the
initial examination for all Inspection Item D welds shall be performed
no sooner than the third refueling outage and no later than 10 years
following stress improvement application. The condition addresses
deferral of the examinations to the end of the interval by repeating
the previous requirement, that is, to perform the initial examination
of Inspection Item D welds no sooner than the third refueling outage
and no later than 10 years following stress improvement application.
Paragraph (g)(6)(ii)(F)(10) is a new condition as a result of
incorporating Code Case N-770-1 in lieu of Code Case N-770. Note 2 of
Figure 5(a) in Code Case N-770-1 permits the use of an alternative
examination volume for an alternative examination volume for welds
mitigated by optimized weld overlays. This alternative examination
volume was not issued as part of the proposed rule and, therefore, this
condition in the final rule prohibits the use of the alternative
examination volume. While the NRC does not have a technical objection
to Note 2 of Figure 5(a), licensees must obtain NRC authorization to
use the alternative examination volume pursuant to 10 CFR
50.55a(a)(3)(i) or (ii).
10 CFR 50.55a(g)(6)(ii)(E)(1) Through (g)(6)(ii)(E)(3)
The NRC is amending paragraphs (g)(6)(ii)(E)(1) through
(g)(6)(ii)(E)(3) to update the requirement to implement Code Case N-
722-1. The amendment also clarifies that for inspections conducted once
per interval, the portion of welds to be inspected in the remaining
portion of the interval is based on rules already established by the
ASME B&PV Code.
Footnote 1 to 10 CFR 50.55a(g)(6)(ii)(E)
The NRC is amending footnote 1 to paragraph (g)(6)(ii)(E) to
clarify that for inspections conducted once per interval, the portion
of welds to be inspected in the remaining portion of the interval be
based on rules already
[[Page 36266]]
established by the ASME B&PV Code, Section XI, paragraph IWB-2400.
Substitution of the Term ``Condition'' in 10 CFR 50.55a
The NRC is amending 10 CFR 50.55a to substitute the words
``limitation(s),'' ``modification(s),'' and ``provision(s)'' with the
word ``condition(s)'' throughout the regulations for consistency.
V. Generic Aging Lessons Learned Report
In December 2010, the NRC issued ``Generic Aging Lessons Learned
(GALL) Report,'' NUREG-1801, Revision 2, for applicants to use in
preparing their license renewal applications. The GALL Report evaluates
existing programs and documents the bases for determining when existing
programs, without change or augmentation, are adequate for aging
management in accordance with the license renewal rule, as given in 10
CFR 54.21(a)(3). In Revision 2 of the GALL Report, editions of the ASME
B&PV Code, Section XI, Subsections IWB, IWC, IWD, IWE, IWF, and IWL
from the 1995 Edition through the 2004 Edition were evaluated and were
found to be acceptable editions and addenda for complying with the
requirements of 10 CFR 54.21(a)(3), unless specifically noted in
certain sections of the GALL Report. For example, GALL Report Section
XI.S1, ``ASME Section XI, Subsection IWE,'' specifically addresses the
1992 Edition of ASME B&PV Code, Section XI, Subsection IWE.
In the GALL Report, Section XI.M1, ``ASME Section XI Inservice
Inspection, Subsections IWB, IWC, and IWD;'' Section XI.S1, ``ASME
Section XI, Subsection IWE;'' Section XI.S2, ``ASME Section XI,
Subsection IWL;'' and Section XI.S3, ``ASME Section XI, Subsection
IWF'' describe the evaluation and technical bases for determining the
adequacy of these ASME Code subsections. In addition, many other aging
management programs (AMPs) in the GALL Report rely in part, but to a
lesser degree, on the requirements in the ASME B&PV Code, Section XI.
The NRC has evaluated Subsections IWB, IWC, IWD, IWE, IWF, and IWL
of Section XI of the ASME B&PV Code, 2004 Edition with the 2005 and
2006 Addenda through the 2007 Edition with the 2008 Addenda as part of
the Sec. 50.55a amendment process to determine if the conclusions of
the GALL Report also apply to AMPs that rely upon the ASME B&PV Code
editions and addenda that are incorporated by reference into Sec.
50.55a by this rule. The NRC finds that the 2004 Edition, inclusive of
the 2005 and 2006 Addenda, and the 2007 Edition, inclusive of the 2008
Addenda of Section XI of the ASME B&PV Code, Subsections IWB, IWC, IWD,
IWE, IWF, and IWL, as subject to the conditions of this rule, are
acceptable to be adopted as AMPs for license renewal and the
conclusions of the GALL Report remain valid, except where specifically
noted and augmented in the GALL Report. Accordingly, an applicant for
license renewal may use, in its plant-specific license renewal
application, Subsections IWB, IWC, IWD, IWE, IWF, and IWL of Section XI
of the 2004 Edition with the 2005 and 2006 Addenda through the 2007
Edition with the 2008 Addenda of the ASME B&PV Code, subject to
conditions in this rule, as acceptable alternatives to the requirements
of the 1995 Edition through the 2004 Edition of the ASME B&PV Code,
Section XI, as referenced in Revision 2 of the GALL Report. Similarly,
a licensee approved for license renewal that relied on the GALL AMPs
may use Subsections IWB, IWC, IWD, IWE, IWF, and IWL of Section XI of
the 2004 Edition inclusive of the 2005 and the 2006 Addenda through the
2007 Edition with the 2008 Addenda of the ASME B&PV Code as acceptable
alternatives to the AMPs described in the Revision 2 of the GALL
report. However, a licensee must assess and follow applicable NRC
requirements with regard to changes to its licensing basis.
The NRC, however, notes that the GALL Report includes Subsection
IWE AMP that is evaluated based on the requirements in the 1992 Edition
through 2004 Edition of Section XI of the ASME B&PV Code. Also, some of
the terminology used and some details in this AMP is based on the 1992
Edition. Since this AMP in Revision 2 of the GALL report has a specific
ASME B&PV Code year in the description of the AMP or in one or more of
the ten elements, the details in the AMP based on a specific ASME B&PV
Code edition may not be accurate for other editions.
Revision 2 of the GALL Report includes AMPs that are based on the
requirements in the 1995 Edition through the 2004 Edition of Section XI
of the ASME B&PV Code but in which the AMPs may recommend additional
augmentation of the Code requirements or the use of specific Code
Edition or Addenda in order to achieve adequate aging management for
license renewal. The technical or regulatory aspects of the AMPs, for
which augmentation is recommended, also apply if using the 2004 Edition
inclusive of the 2005 Addenda, or the 2007 Edition, inclusive of the
2008 Addenda, of Section XI of the ASME B&PV Code to meet the
requirements of 10 CFR 54.21(a)(3). A license renewal applicant may
either augment its AMPs in these areas, as described in the GALL
report, or propose alternatives (exceptions) for the NRC to review as
part of a plant-specific program element justification for its AMP.GALL
Revision 1, in AMP XI.M11A, provides an acceptable approach for aging
management--through inservice inspection--of PWR nickel-alloy upper
vessel head penetration nozzles. This inservice inspection is the same
as the inservice inspection mandated by Order EA-03-009, ``Issuance of
Order Establishing Interim Inspection Requirements for Reactor Pressure
Vessel Heads at Pressurized Water Reactors (PWRs),'' as amended by the
First Revision of the Order. GALL Revision 2, in GALL AMP XI.M11B,
``Cracking of Nickel-Alloy Components and Loss of Material Due to Boric
Acid-Induced Corrosion in Reactor Coolant Pressure Boundary Components
(PWRs Only),'' provides inspection guidance for all PWR nickel-alloy
reactor coolant pressure boundary (RCPB) components (including nickel-
alloy welds) and nickel alloy aging management review line items. Thus,
AMP XI.M11B in GALL Revision 2 supersedes the provisions of GALL
Revision 1 AMP XI.M11A. GALL Revision 2 AMP XI.M11B is based on, and is
consistent with the provisions of several ASME Code Cases addressing
inspection of nickel alloy upper vessel head penetration nozzles which
have been endorsed by the NRC (with conditions in 10 CFR 50.55a).
Accordingly, new or current license renewal applicants who identify
consistency with GALL AMP XI.M11B through compliance with 10 CFR
50.55a(g)(6)(ii)(D), (g)(6)(ii)(E), and (g)(6)(ii)(F) need not take an
exception to the program elements in GALL AMP XI.M11B. Licensees that
have been granted a renewed operating license will eventually update
their ISI programs to comply with the Code Cases on inspection of
nickel alloy upper vessel head penetration nozzles, in accordance with
Sec. 50.55a(g). Accordingly, these licensees will eventually become
consistent with GALL AMP XI.M11B.
VI. Availability of Documents
The NRC is making the documents identified below available to
interested persons through one or more of the following:
Public Document Room (PDR): The NRC PDR is located at 11555
Rockville Pike, Room O-1F21, Rockville, Maryland 20852.
[[Page 36267]]
Federal rulemaking Web site: Public comments and supporting
material related to this final rule can be found at http://regulations.gov by searching on the Docket ID NRC-2008-0554.
The NRC's Library: The NRC's Library is located at http://www.nrc.gov/reading-rm.html.
------------------------------------------------------------------------
Rulemaking web
Document PDR site Library
------------------------------------------------------------------------
Analysis of Public Comments.. X .............. ML110280240.
ASME B&PV Code *............. X ..............
ASME Code Case N-770-1 *..... X ..............
ASME Code Case N-722-1 *..... X ..............
ASME OM Code *............... X ..............
EPRI Report NP-5151 **, ...... ..............
``Evaluation of Reactor
Vessel Beltline Integrity
Following Unanticipated
Operating Events,'' April
1987.
GALL Report, NUREG-1801, X .............. ML052770419.
Rev.1, September 2005,.
Volume 1..................... X .............. ML052780376.
Volume 2..................... ...... ..............
NQA-1 *, ``Quality Assurance
Requirements for Nuclear
Facilities,'' 1994 Edition.
NUREG-0800, ``Standard Review X .............. reading-rm/doc-
Plan for the Review of collections/
Safety Analysis Reports for nuregs/staff/
Nuclear Power Plants--LWR sr0800/.
Edition.
PNNL-19086, ``Replacement of ...... .............. ML1010312543.
Radiography with Ultrasonics
for the Nondestructive
Inspection of Welds--
Evaluation of Technical
Gaps--An Interim Report''.
Public Submissions (Comments) ...... X ML103200546.
on Proposed Rule.
Regulatory Analysis and X X ML110320011.
Backfit Considerations for
Final Amendment 10 CFR
50.55a, ``Codes and
Standards''.
Regulatory Guide 1.178, ``An X .............. ML032510128.
Approach for Plant-Specific
Risk-Informed Decisionmaking
for Inservice Inspection of
Piping''.
Regulatory Guide 1.193, X .............. ML072470294.
Revision 2, ``ASME Code
Cases not Approved for Use''.
Regulatory Guide 1.200, ``An X .............. ML090410014.
Approach for Determining the
Technical Adequacy of
Probabilistic Risk
Assessment Results for Risk-
Informed Activities''.
``Review of Changes Between X .............. ML111250292.
American Society of
Mechanical Engineers Boiler
and Pressure Vessel Code
Cases N-770 and N-770-1 to
Support 10 CFR 50.55a Final
Rule''.
Standard Review Plan 3.9.8, X .............. ML032510135.
``Risk-Informed Inservice
Inspection of Piping''
------------------------------------------------------------------------
* Available on the ASME Web site.
** Available on the EPRI Web site.
VII. Voluntary Consensus Standards
Section 12(d)(3) of the National Technology Transfer and
Advancement Act of 1995, Public Law 104-113 (NTTAA), and implementing
guidance in U.S. Office of Management and Budget (OMB) Circular A-119
(February 10, 1998), requires each Federal government agency (should it
decide that regulation is necessary) to use a voluntary consensus
standard instead of developing a government-unique standard. An
exception to using a voluntary consensus standard is allowed where the
use of such a standard is inconsistent with applicable law or is
otherwise impractical. The NTTAA requires Federal agencies to use
industry consensus standards to the extent practical; it does not
require Federal agencies to endorse a standard in its entirety. Neither
the NTTAA nor Circular A-119 prohibit an agency from adopting a
voluntary consensus standard while taking exception to specific
portions of the standard, if those provisions are deemed to be
``inconsistent with applicable law or otherwise impractical.''
Furthermore, taking specific exceptions furthers the Congressional
intent of Federal reliance on voluntary consensus standards because it
allows the adoption of substantial portions of consensus standards
without the need to reject the standards in their entirety because of
limited provisions which are not acceptable to the agency.
In this rulemaking, the NRC is continuing its existing practice of
establishing requirements for the design, construction, operation, ISI
(examination) and IST of nuclear power plants by approving the use of
the latest editions and addenda of the ASME Codes in 10 CFR 50.55a. The
ASME Codes are voluntary consensus standards, developed by participants
with broad and varied interests, in which all interested parties
(including the NRC and licensees of nuclear power plants) participate.
Therefore, the NRC's incorporation by reference of the ASME Codes is
consistent with the overall objectives of the NTTAA and OMB Circular A-
119.
As discussed in Section III of this statement of considerations, in
this final rule the NRC is conditioning the use of certain provisions
of the 2005 Addenda through 2008 Addenda of Section III, Division 1,
and the 2005 Addenda through 2008 Addenda of Section XI, Division 1, of
the ASME B&PV Code; and the 2005 Addenda and 2006 Addenda of the ASME
OM Code, and Code Cases N-722-1 and N-770-1. In addition, the final
rule does not adopt (``excludes'') certain provisions of the ASME Codes
and this statement of considerations, and in the regulatory and backfit
analysis for this rulemaking. The NRC believes that this final rule
complies with the NTTAA and OMB Circular A-119 despite these conditions
and ``exclusions.''
If the NRC did not conditionally accept ASME editions, addenda, and
code cases, the NRC would disapprove these entirely. The effect would
be that licensees and applicants would submit a larger number of
requests for use of alternatives under Sec. 50.55a(a)(3), requests for
relief under Sec. 50.55a(f) and (g), or requests for exemptions under
10 CFR 50.12 and/or 10 CFR 52.7. These requests would likely include
broad-scope requests for approval to issue the full scope of the ASME
Code editions and addenda which would otherwise be approved in this
final rulemaking (i.e., the request would not be simply for approval of
a specific ASME Code provision with conditions). These requests would
be an unnecessary additional burden for both the licensee
[[Page 36268]]
and the NRC, inasmuch as the NRC has already determined that the ASME
Codes and Code Cases which are the subject of this final rulemaking are
acceptable for use (in some cases with conditions). For these reasons,
the NRC concludes that this final rule's treatment of ASME Code
editions and addenda, and code cases and any conditions placed on them
does not conflict with any policy on agency use of consensus standards
specified in OMB Circular A 119.
The NRC did not identify any other voluntary consensus standards,
developed by US voluntary consensus standards bodies for use within the
US, which the NRC could incorporate by reference instead of the ASME
Codes. The NRC also did not identify any voluntary consensus standards,
developed by multinational voluntary consensus standards bodies for use
on a multinational basis, which the NRC could incorporate by reference
instead of the ASME Codes. The NRC identified codes addressing the same
subject as the ASME Codes for use in individual countries. At least one
country, Korea, directly translated the ASME Code for use in that
country. In other countries (e.g., Japan), ASME Codes were the basis
for development of the country's codes, but the ASME Codes were
substantially modified to accommodate that country's regulatory system
and reactor designs. Finally, there are countries (e.g., the Russian
Federation) where that country's code was developed without regard to
the ASME Code. However, some of these codes may not meet the definition
of a voluntary consensus standard, because they were developed by the
state rather than a voluntary consensus standards body. NRC evaluation
of the countries codes to determine whether each code provides a
comparable or enhanced level of safety when compared against the level
of safety provided under the ASME Codes would require a significant
expenditure of agency resources. This expenditure does not seem
justified, given that substituting another country's code for the US
voluntary consensus standard does not appear to substantially further
the apparent underlying objectives of the NTTAA.
In summary, this final rulemaking satisfies the requirements of the
Section 12(d)(3) of the NTTAA and Office of Management and Budget (OMB)
Circular A 119.
VIII. Finding of No Significant Environmental Impact: Environmental
Assessment
This final rule action is in accordance with the NRC's policy to
incorporate by reference in 10 CFR 50.55a new editions and addenda of
the ASME B&PV and OM Codes to provide updated rules for constructing
and inspecting components and testing pumps, valves, and dynamic
restraints (snubbers) in light-water nuclear power plants. ASME Codes
are national voluntary consensus standards and are required by the
National Technology Transfer and Advancement Act of 1995, Public Law
104-113, to be used by government agencies unless the use of such a
standard is inconsistent with applicable law or otherwise impractical.
The National Environmental Policy Act (NEPA) requires Federal
government agencies to study the impacts of their ``major Federal
actions significantly affecting the quality of the human environment,''
and prepare detailed statements on the environmental impacts of the
proposed action and alternatives to the proposed action (42 U.S.C. Sec.
4332(C); NEPA Sec. 102(C)).
The NRC has determined under NEPA, as amended, and the NRC's
regulations in Subpart A of 10 CFR part 51, that this final rule is not
a major Federal action significantly affecting the quality of the human
environment and, therefore, an environmental impact statement is not
required. The final rulemaking does not significantly increase the
probability or consequences of accidents; no changes are being made in
the types of effluents that may be released off-site; and there is no
significant increase in public radiation exposure. The NRC estimates
the radiological dose to plant personnel performing the inspections
required by Code Case N-770-1 would be about 3 rem per plant over a 10-
year interval, and a one-time exposure for mitigating welds of about 30
rem per plant. As required by 10 CFR part 20, and in accordance with
current plant procedures and radiation protection programs, plant
radiation protection staff will continue monitoring dose rates and
would make adjustments in shielding, access requirements,
decontamination methods, and procedures as necessary to minimize the
dose to workers. The increased occupational dose to individual workers
stemming from the Code Case N-770-1 inspections must be maintained
within the limits of 10 CFR part 20 and as low as reasonably
achievable. Therefore, the NRC concludes that the increase in
occupational exposure would not be significant. The final rulemaking
does not involve non-radiological plant effluents and has no other
environmental impact. Therefore, no significant non-radiological
impacts are associated with this action. The determination of this
final environmental assessment is that there will be no significant
off-site impact to the public from this action.
IX. Paperwork Reduction Act Statement
This final rule decreases the overall burden on licensees by
reducing the number of relief requests licensees would have to submit
to the NRC under 10 CFR 50.55a(f)(5) and 10 CFR 50.55a(g)(5), but adds
burden for 69 Pressurized Water Reactors (PWRs) to revise procedures
and programs related to ASME Code Case N-770-1. The public burden
reduction for these information collections is estimated to average -4
hours per response. Because the burden for this information collection
is insignificant, Office of Management and Budget (OMB) clearance is
not required. Existing requirements were approved by the Office of
Management and Budget, approval number 3150-0011.
Public Protection Notification
The NRC may not conduct or sponsor, and a person is not required to
respond to, a request for information or an information collection
requirement unless the requesting document displays a currently valid
OMB control number.
X. Regulatory Analysis and Backfitting
The NRC prepared a document, ``Regulatory Analysis and Backfit
Considerations for Final Amendment 10 CFR 50.55a, ``Codes and
Standards''''. The document provides the regulatory analysis for this
final rule. It also addresses backfitting for the final rule and
provides the basis for the NRC's determination that the final rule does
not constitute ``backfitting'' as defined in 10 CFR 50.109(a)(4). The
analysis is available for review as indicated in Section VI,
``Availability of Documents,'' of this document.
XI. Regulatory Flexibility Certification
Under the Regulatory Flexibility Act of 1980 (5 U.S.C. 605(b)), the
NRC certifies that this final rule does not impose a significant
economical impact on a substantial number of small entities. This final
rule affects only the licensing and operation of commercial nuclear
power plants. A licensee who is a subsidiary of a large entity does not
qualify as a small entity. The companies that own these plants are not
``small entities'' as defined in the Regulatory Flexibility Act or the
size standards established by the NRC (10 CFR 2.810), as the companies:
[[Page 36269]]
Provide services that are not engaged in manufacturing,
and have average gross receipts of more than $6.5 million over their
last 3 completed fiscal years, and have more than 500 employees;
Are not governments of a city, county, town, township or
village;
Are not school districts or special districts with
populations of less than 50; and
Are not small educational institutions.
XII. Congressional Review Act
In accordance with the Congressional Review Act of 1996, the NRC
has determined that this action is not a major rule and has verified
this determination with the Office of Information and Regulatory
Affairs of the Office of Management and Budget.
List of Subjects in 10 CFR Part 50
Antitrust, Classified information, Criminal penalties, Fire
protection, Incorporation by reference, Intergovernmental relations,
Nuclear power plants and reactors, Radiation protection, Reactor siting
criteria, Reporting and recordkeeping requirements.
For the reasons set forth in the preamble, and under the authority
of the Atomic Energy Act of 1954, as amended; the Energy Reorganization
Act of 1974, as amended; and 5 U.S.C. 552 and 553, the NRC is adopting
the following amendments to 10 CFR part 50.
PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION
FACILITIES
0
1. The authority citation for part 50 continues to read as follows:
Authority: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68
Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234,
83 Stat. 444, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201,
2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88
Stat. 1242, as amended, 1244, 1246 (42 U.S.C. 5841, 5842, 5846);
sec. 1704, 112 Stat. 2750 (44 U.S.C. 3504 note); Energy Policy Act
of 2005, Pub. L. 109-58, 119 Stat. 194 (2005).
Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat.
2951 as amended by Pub. L. 102-486, sec. 2902, 106 Stat. 3123 (42
U.S.C. 5841), Section 50.10 also issued under secs. 101, 185, 68
Stat. 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L. 91-
190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd), and
50.103 also issued under sec. 108, 68 Stat. 939, as amended (42
U.S.C. 2138).
Sections 50.23, 50.35, 50.55, and 50.56 also issued under sec.
185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a, 50.55a and
Appendix Q also issued under sec. 102, Pub. L. 91-190, 83 Stat. 853
(42 U.S.C. 4332). Sections 50.34 and 50.54 also issued under sec.
204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58, 50.91, and
50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42 U.S.C.
2239). Section 50.78 also issued under sec. 122, 68 Stat. 939 (42
U.S.C. 2152). Sections 50.80-50.81 also issued under sec. 184, 68
Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued under
sec. 187, 68 Stat. 955 (42 U.S.C. 2237).
0
2. In Sec. 50.55a:
0
a. Revise paragraph (a), the introductory text of paragraphs (b) and
(b)(1), paragraphs (b)(1)(ii), (b)(1)(iii), and (b)(1)(iv); and add
paragraph (b)(1)(vii);
0
b. Revise paragraph (b)(2);
0
c. Revise the introductory text of paragraph (b)(3), paragraphs
(b)(3)(v), (b)(3)(vi), (c)(3), (d)(2), (e)(2), (f)(2), (f)(3)(v),
(f)(4), (f)(5)(iv), (g)(2), (g)(3), (g)(4), (g)(5)(iii), (g)(5)(iv),
(g)(6)(ii)(B), (g)(6)(ii)(E)(1), (g)(6)(ii)(E)(2), and
(g)(6)(ii)(E)(3);
0
d. Add paragraph (g)(6)(ii)(F); and
0
e. Revise footnote 1 to this section that appears after paragraph
(h)(3).
The revisions and additions read as follows:
Sec. 50.55a Codes and standards.
* * * * *
(a) Quality standards, ASME Codes and IEEE standards, and
alternatives.
(1) Structures, systems, and components must be designed,
fabricated, erected, constructed, tested, and inspected to quality
standards commensurate with the importance of the safety function to be
performed.
(2) Systems and components of boiling and pressurized water-cooled
nuclear power reactors must meet the requirements of the ASME Boiler
and Pressure Vessel Code specified in paragraphs (b), (c), (d), (e),
(f), and (g) of this section. Protection systems of nuclear power
reactors of all types must meet the requirements specified in paragraph
(h) of this section.
(3) Proposed alternatives to the requirements of paragraphs (c),
(d), (e), (f), (g), and (h) of this section, or portions thereof, may
be used when authorized by the Director, Office of Nuclear Reactor
Regulation, or Director, Office of New Reactors, as appropriate. Any
proposed alternatives must be submitted and authorized prior to
implementation. The applicant or licensee shall demonstrate that:
(i) The proposed alternatives would provide an acceptable level of
quality and safety; or
(ii) Compliance with the specified requirements of this section
would result in hardship or unusual difficulty without a compensating
increase in the level of quality and safety.
(b) Standards approved for incorporation by reference. Systems and
components of boiling and pressurized water cooled nuclear power
reactors must meet the requirements of the following standards
referenced in paragraphs (b)(1), (b)(2), (b)(3), (b)(4), (b)(5), and
(b)(6) of this section: The ASME Boiler and Pressure Vessel Code,
Section III, Division 1 (excluding Non-mandatory Appendices), and
Section XI, Division 1; the ASME Code for Operation and Maintenance of
Nuclear Power Plants; NRC Regulatory Guide (RG) 1.84, Revision 35,
``Design, Fabrication, and Materials Code Case Acceptability, ASME
Section III'' (July 2010), RG 1.147, Revision 16, ``Inservice
Inspection Code Case Acceptability, ASME Section XI, Division 1'' (July
2010), and RG 1.192, ``Operation and Maintenance Code Case
Acceptability, ASME OM Code'' (March 2003); and the following ASME Code
Cases, approved with conditions by the NRC: N-722-1, ``Additional
Examinations for PWR Pressure Retaining Welds in Class 1 Components
Fabricated with Alloy 600/82/182 Materials, Section XI, Division 1''
(ASME Approval Date: January 26, 2009), in accordance with the
requirements in paragraph (g)(6)(ii)(E) of this section; N-729-1,
``Alternative Examination Requirements for PWR Reactor Vessel Upper
Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds,
Section XI, Division 1'' (ASME Approval Date: March 28, 2006), in
accordance with the requirements in paragraph (g)(6)(ii)(D) of this
section; and N-770-1, ``Alternative Examination Requirements and
Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt
Welds Fabricated with UNS N06082 or UNS W86182 Weld Filler Material
With or Without Application of Listed Mitigation Activities, Section
XI, Division 1,'' (ASME Approval Date: December 25, 2009), in
accordance with the requirements in paragraph (g)(6)(ii)(F) of this
section. These standards have been approved for incorporation by
reference by the Director of the Federal Register pursuant to 5 U.S.C.
552(a) and 1 CFR part 51. Copies of the ASME Boiler and Pressure Vessel
Code, the ASME Code for Operation and Maintenance of Nuclear Power
Plants, ASME Code Case N-722-1, ASME Code Case N-729-1, and ASME Code
Case N-770-1 may be purchased from the American Society of Mechanical
Engineers, Three Park Avenue, New York, NY 10016, phone 800-843-2763,
or through the Web http://www.asme.org/Codes/. Single copies of NRC
Regulatory Guides 1.84,
[[Page 36270]]
Revision 35; 1.147, Revision 16; and 1.192 may be obtained free of
charge by writing the Reproduction and Distribution Services Section,
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; or by
fax to 301-415-2289; or by e-mail to [email protected].
Copies of the ASME Codes and NRC Regulatory Guides incorporated by
reference in this section may be inspected at the NRC Technical
Library, Two White Flint North, 11545 Rockville Pike, Rockville, MD
20852-2738 or call 301-415-5610, or at the National Archives and
Records Administration (NARA). For information on the availability of
this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.
(1) As used in this section, references to Section III refer to
Section III of the ASME Boiler and Pressure Vessel Code, and include
the 1963 Edition through 1973 Winter Addenda, and the 1974 Edition
(Division 1) through the 2008 Addenda (Division 1), subject to the
following conditions:
* * * * *
(ii) Weld leg dimensions. When applying the 1989 Addenda through
the latest edition and addenda incorporated by reference in paragraph
(b)(1) of this section, applicants or licensees may not apply
subparagraphs NB-3683.4(c)(1) and NB-3683.4(c)(2) or Footnote 11 from
the 1989 Addenda through the 2003 Addenda, or Footnote 13 from the 2004
Edition through the 2008 Addenda to Figures NC-3673.2(b)-1 and ND-
3673.2(b)-1 for welds with leg size less than 1.09 tn.
(iii) Seismic design of piping. Applicants or licensees may use
Subarticles NB-3200, NB-3600, NC-3600, and ND-3600 for seismic design
of piping, up to and including the 1993 Addenda, subject to the
condition specified in paragraph (b)(1)(ii) of this section. Applicants
or licensees may not use these subarticles for seismic design of piping
in the 1994 Addenda through the 2005 Addenda incorporated by reference
in paragraph (b)(1) of this section except that Subarticle NB-3200 in
the 2004 Edition through the 2008 Addenda may be used by applicants and
licensees subject to the condition in paragraph (b)(1)(iii)(B) of this
section. Applicants or licensees may use Subarticles NB-3600, NC-3600
and ND-3600 for the seismic design of piping in the 2006 Addenda
through the 2008 Addenda subject to the conditions of this paragraph
corresponding to these subarticles.
(A) When applying Note (1) of Figure NB-3222-1 for Level B service
limits, the calculation of Pb stresses must include
reversing dynamic loads (including inertia earthquake effects) if
evaluation of these loads is required by NB-3223(b).
(B) For Class 1 piping, the material and Do/t
requirements of NB-3656(b) shall be met for all Service Limits when the
Service Limits include reversing dynamic loads, and the alternative
rules for reversing dynamic loads are used.
(iv) Quality assurance. When applying editions and addenda later
than the 1989 Edition of Section III, the requirements of NQA-1,
``Quality Assurance Requirements for Nuclear Facilities,'' 1986 Edition
through the 1994 Edition, are acceptable for use, provided that the
edition and addenda of NQA-1 specified in NCA-4000 is used in
conjunction with the administrative, quality, and technical provisions
contained in the edition and addenda of Section III being used.
* * * * *
(vii) Capacity certification and demonstration of function of
incompressible-fluid pressure-relief valves. When applying the 2006
Addenda through the 2007 Edition up to and including the 2008 Addenda,
applicants and licensees may use paragraph NB-7742, except that
paragraph NB-7742(a)(2) may not be used, and for a valve design of a
single size to be certified over a range of set pressures, the
demonstration of function tests under paragraph NB-7742 must be
conducted as prescribed in NB-7732.2 on two valves covering the minimum
set pressure for the design and the maximum set pressure which can be
accommodated at the demonstration facility selected for the test.
(2) As used in this section, references to Section XI refer to
Section XI, Division 1, of the ASME Boiler and Pressure Vessel Code,
and include the 1970 Edition through the 1976 Winter Addenda, and the
1977 Edition through the 2007 Edition with the 2008 Addenda, subject to
the following conditions:
(i) [Reserved]
(ii) Pressure-retaining welds in ASME Code Class 1 piping (applies
to Table IWB-2500 and IWB-2500-1 and Category B-J). If the facility's
application for a construction permit was docketed prior to July 1,
1978, the extent of examination for Code Class 1 pipe welds may be
determined by the requirements of Table IWB-2500 and Table IWB-2600
Category B-J of Section XI of the ASME B&PV Code in the 1974 Edition
and addenda through the Summer 1975 Addenda or other requirements the
NRC may adopt.
(iii) [Reserved]
(iv) [Reserved]
(v) [Reserved]
(vi) Effective edition and addenda of Subsection IWE and Subsection
IWL, Section XI. Applicants or licensees may use either the 1992
Edition with the 1992 Addenda or the 1995 Edition with the 1996 Addenda
of Subsection IWE and Subsection IWL as conditioned by the requirements
in paragraphs (b)(2)(viii) and (b)(2)(ix) of this section when
implementing the initial 120-month inspection interval for the
containment inservice inspection requirements of this section.
Successive 120-month interval updates must be implemented in accordance
with paragraph (g)(4)(ii) of this section.
(vii) Section XI References to OM Part 4, OM Part 6 and OM Part 10
(Table IWA-1600-1). When using Table IWA-1600-1, ``Referenced Standards
and Specifications,'' in the Section XI, Division 1, 1987 Addenda, 1988
Addenda, or 1989 Edition, the specified ``Revision Date or Indicator''
for ASME/ANSI OM part 4, ASME/ANSI part 6, and ASME/ANSI part 10 must
be the OMa-1988 Addenda to the OM-1987 Edition. These requirements have
been incorporated into the OM Code which is incorporated by reference
in paragraph (b)(3) of this section.
(viii) Examination of concrete containments. Applicants or
licensees applying Subsection IWL, 1992 Edition with the 1992 Addenda,
shall apply paragraphs (b)(2)(viii)(A) through (b)(2)(viii)(E) of this
section. Applicants or licensees applying Subsection IWL, 1995 Edition
with the 1996 Addenda, shall apply paragraphs (b)(2)(viii)(A),
(b)(2)(viii)(D)(3), and (b)(2)(viii)(E) of this section. Applicants or
licensees applying Subsection IWL, 1998 Edition through the 2000
Addenda shall apply paragraphs (b)(2)(viii)(E) and (b)(2)(viii)(F) of
this section. Applicants or licensees applying Subsection IWL, 2001
Edition through the 2004 Edition, up to and including the 2006 Addenda,
shall apply paragraphs (b)(2)(viii)(E) through (b)(2)(viii)(G) of this
section. Applicants or licensees applying Subsection IWL, 2007 Edition
through the latest edition and addenda incorporated by reference in
paragraph (b)(2) of this section, shall apply paragraph (b)(2)(viii)(E)
of this section.
(A) Grease caps that are accessible must be visually examined to
detect grease leakage or grease cap deformations. Grease caps must be
removed for this examination when there is evidence of grease cap
[[Page 36271]]
deformation that indicates deterioration of anchorage hardware.
(B) When evaluation of consecutive surveillances of prestressing
forces for the same tendon or tendons in a group indicates a trend of
prestress loss such that the tendon force(s) would be less than the
minimum design prestress requirements before the next inspection
interval, an evaluation must be performed and reported in the
Engineering Evaluation Report as prescribed in IWL-3300.
(C) When the elongation corresponding to a specific load (adjusted
for effective wires or strands) during retensioning of tendons differs
by more than 10 percent from that recorded during the last measurement,
an evaluation must be performed to determine whether the difference is
related to wire failures or slip of wires in anchorage. A difference of
more than 10 percent must be identified in the ISI Summary Report
required by IWA-6000.
(D) The applicant or licensee shall report the following
conditions, if they occur, in the ISI Summary Report required by IWA-
6000:
(1) The sampled sheathing filler grease contains chemically
combined water exceeding 10 percent by weight or the presence of free
water;
(2) The absolute difference between the amount removed and the
amount replaced exceeds 10 percent of the tendon net duct volume;
(3) Grease leakage is detected during general visual examination of
the containment surface.
(E) For Class CC applications, the applicant or licensee shall
evaluate the acceptability of inaccessible areas when conditions exist
in accessible areas that could indicate the presence of or result in
degradation to such inaccessible areas. For each inaccessible area
identified, the applicant or licensee shall provide the following in
the ISI Summary Report required by IWA-6000:
(1) A description of the type and estimated extent of degradation,
and the conditions that led to the degradation;
(2) An evaluation of each area, and the result of the evaluation,
and;
(3) A description of necessary corrective actions.
(F) Personnel that examine containment concrete surfaces and tendon
hardware, wires, or strands must meet the qualification provisions in
IWA-2300. The ``owner-defined'' personnel qualification provisions in
IWL-2310(d) are not approved for use.
(G) Corrosion protection material must be restored following
concrete containment post-tensioning system repair and replacement
activities in accordance with the quality assurance program
requirements specified in IWA-1400.
(ix) Examination of metal containments and the liners of concrete
containments. Applicants or licensees applying Subsection IWE, 1992
Edition with the 1992 Addenda, or the 1995 Edition with the 1996
Addenda, shall satisfy the requirements of paragraphs (b)(2)(ix)(A)
through (b)(2)(ix)(E) of this section. Applicants or licensees applying
Subsection IWE, 1998 Edition through the 2001 Edition with the 2003
Addenda, shall satisfy the requirements of paragraphs (b)(2)(ix)(A),
(b)(2)(ix)(B), and (b)(2)(ix)(F) through (b)(2)(ix)(I) of this section.
Applicants or licensees applying Subsection IWE, 2004 Edition, up to
and including the 2005 Addenda, shall satisfy the requirements of
paragraphs (b)(2)(ix)(A), (b)(2)(ix)(B), and (b)(2)(ix)(F) through
(b)(2)(ix)(H) of this section. Applicants or licensees applying
Subsection IWE, 2004 Edition with the 2006 Addenda, shall satisfy the
requirements of paragraphs (b)(2)(ix)(A)(2) and (b)(2)(ix)(B) of this
section. Applicants or licensees applying Subsection IWE, 2007 Edition
through the latest addenda incorporated by reference in paragraph
(b)(2) of this section, shall satisfy the requirements of paragraphs
(b)(2)(ix)(A)(2), (b)(2)(ix)(B) and (b)(2)(ix)(J) of this section.
(A) For Class MC applications, the following apply to inaccessible
areas.
(1) The applicant or licensee shall evaluate the acceptability of
inaccessible areas when conditions exist in accessible areas that could
indicate the presence of or result in degradation to such inaccessible
areas.
(2) For each inaccessible area identified for evaluation, the
applicant or licensee shall provide the following in the ISI Summary
Report as required by IWA-6000:
(i) A description of the type and estimated extent of degradation,
and the conditions that led to the degradation;
(ii) An evaluation of each area, and the result of the evaluation,
and;
(iii) A description of necessary corrective actions.
(B) When performing remotely the visual examinations required by
Subsection IWE, the maximum direct examination distance specified in
Table IWA-2210-1 may be extended and the minimum illumination
requirements specified in Table IWA-2210-1 may be decreased provided
that the conditions or indications for which the visual examination is
performed can be detected at the chosen distance and illumination.
(C) The examinations specified in Examination Category E-B,
Pressure Retaining Welds, and Examination Category E-F, Pressure
Retaining Dissimilar Metal Welds, are optional.
(D) This paragraph (b)(2)(ix)(D) may be used as an alternative to
the requirements of IWE-2430.
(1) If the examinations reveal flaws or areas of degradation
exceeding the acceptance standards of Table IWE-3410-1, an evaluation
must be performed to determine whether additional component
examinations are required. For each flaw or area of degradation
identified which exceeds acceptance standards, the applicant or
licensee shall provide the following in the ISI Summary Report required
by IWA-6000:
(i) A description of each flaw or area, including the extent of
degradation, and the conditions that led to the degradation;
(ii) The acceptability of each flaw or area, and the need for
additional examinations to verify that similar degradation does not
exist in similar components, and;
(iii) A description of necessary corrective actions.
(2) The number and type of additional examinations to ensure
detection of similar degradation in similar components.
(E) A general visual examination as required by Subsection IWE must
be performed once each period.
(F) VT-1 and VT-3 examinations must be conducted in accordance with
IWA-2200. Personnel conducting examinations in accordance with the VT-1
or VT-3 examination method shall be qualified in accordance with IWA-
2300. The ``owner-defined'' personnel qualification provisions in IWE-
2330(a) for personnel that conduct VT-1 and VT-3 examinations are not
approved for use.
(G) The VT-3 examination method must be used to conduct the
examinations in Items E1.12 and E1.20 of Table IWE-2500-1, and the VT-1
examination method must be used to conduct the examination in Item
E4.11 of Table IWE-2500-1. An examination of the pressure-retaining
bolted connections in Item E1.11 of Table IWE-2500-1 using the VT-3
examination method must be conducted once each interval. The ``owner-
defined'' visual examination provisions in IWE-2310(a) are not approved
for use for VT-1 and VT-3 examinations.
(H) Containment bolted connections that are disassembled during the
scheduled performance of the examinations in Item E1.11 of Table IWE-
2500-1 must be examined using
[[Page 36272]]
the VT-3 examination method. Flaws or degradation identified during the
performance of a VT-3 examination must be examined in accordance with
the VT-1 examination method. The criteria in the material specification
or IWB-3517.1 must be used to evaluate containment bolting flaws or
degradation. As an alternative to performing VT-3 examinations of
containment bolted connections that are disassembled during the
scheduled performance of Item E1.11, VT-3 examinations of containment
bolted connections may be conducted whenever containment bolted
connections are disassembled for any reason.
(I) The ultrasonic examination acceptance standard specified in
IWE-3511.3 for Class MC pressure-retaining components must also be
applied to metallic liners of Class CC pressure-retaining components.
(J) In general, a repair/replacement activity such as replacing a
large containment penetration, cutting a large construction opening in
the containment pressure boundary to replace steam generators, reactor
vessel heads, pressurizers, or other major equipment; or other similar
modification is considered a major containment modification. When
applying IWE-5000 to Class MC pressure-retaining components, any major
containment modification or repair/replacement, must be followed by a
Type A test to provide assurance of both containment structural
integrity and leaktight integrity prior to returning to service, in
accordance with 10 CFR part 50, Appendix J, Option A or Option B on
which the applicant's or licensee's Containment Leak-Rate Testing
Program is based. When applying IWE-5000, if a Type A, B, or C Test is
performed, the test pressure and acceptance standard for the test must
be in accordance with 10 CFR part 50, Appendix J.
(x) Quality assurance. When applying Section XI editions and
addenda later than the 1989 Edition, the requirements of NQA-1,
``Quality Assurance Requirements for Nuclear Facilities,'' 1979 Addenda
through the 1989 Edition, are acceptable as permitted by IWA-1400 of
Section XI, if the licensee uses its 10 CFR part 50, Appendix B,
quality assurance program, in conjunction with Section XI requirements.
Commitments contained in the licensee's quality assurance program
description that are more stringent than those contained in NQA-1 must
govern Section XI activities. Further, where NQA-1 and Section XI do
not address the commitments contained in the licensee's Appendix B
quality assurance program description, the commitments must be applied
to Section XI activities.
(xi) [Reserved]
(xii) Underwater welding. The provisions in IWA-4660, ``Underwater
Welding,'' of Section XI, 1997 Addenda through the latest edition and
addenda incorporated by reference in paragraph (b)(2) of this section,
are not approved for use on irradiated material.
(xiii) [Reserved]
(xiv) Appendix VIII personnel qualification. All personnel
qualified for performing ultrasonic examinations in accordance with
Appendix VIII shall receive 8 hours of annual hands-on training on
specimens that contain cracks. Licensees applying the 1999 Addenda
through the latest edition and addenda incorporated by reference in
paragraph (b)(2) of this section may use the annual practice
requirements in VII-4240 of Appendix VII of Section XI in place of the
8 hours of annual hands-on training provided that the supplemental
practice is performed on material or welds that contain cracks, or by
analyzing prerecorded data from material or welds that contain cracks.
In either case, training must be completed no earlier than 6 months
prior to performing ultrasonic examinations at a licensee's facility.
(xv) Appendix VIII specimen set and qualification requirements.
Licensees using Appendix VIII in the 1995 Edition through the 2001
Edition of the ASME Boiler and Pressure Vessel Code may elect to comply
with all of the provisions in paragraphs (b)(2)(xv)(A) through
(b)(2)(xv)(M) of this section, except for paragraph (b)(2)(xv)(F) of
this section, which may be used at the licensee's option. Licensees
using editions and addenda after 2001 Edition through the 2006 Addenda
shall use the 2001 Edition of Appendix VIII, and may elect to comply
with all of the provisions in paragraphs (b)(2)(xv)(A) through
(b)(2)(xv)(M) of this section, except for paragraph (b)(2)(xv)(F) of
this section, which may be used at the licensee's option.
(A) When applying Supplements 2, 3, and 10 to Appendix VIII, the
following examination coverage criteria requirements must be used:
(1) Piping must be examined in two axial directions, and when
examination in the circumferential direction is required, the
circumferential examination must be performed in two directions,
provided access is available. Dissimilar metal welds must be examined
axially and circumferentially.
(2) Where examination from both sides is not possible, full
coverage credit may be claimed from a single side for ferritic welds.
Where examination from both sides is not possible on austenitic welds
or dissimilar metal welds, full coverage credit from a single side may
be claimed only after completing a successful single-sided Appendix
VIII demonstration using flaws on the opposite side of the weld.
Dissimilar metal weld qualifications must be demonstrated from the
austenitic side of the weld, and the qualification may be expanded for
austenitic welds with no austenitic sides using a separate add-on
performance demonstration. Dissimilar metal welds may be examined from
either side of the weld.
(B) The following conditions must be used in addition to the
requirements of Supplement 4 to Appendix VIII:
(1) Paragraph 3.1, Detection acceptance criteria--Personnel are
qualified for detection if the results of the performance demonstration
satisfy the detection requirements of ASME Section XI, Appendix VIII,
Table VIII-S4-1 and no flaw greater than 0.25 inch through wall
dimension is missed.
(2) Paragraph 1.1(c), Detection test matrix--Flaws smaller than the
50 percent of allowable flaw size, as defined in IWB-3500, need not be
included as detection flaws. For procedures applied from the inside
surface, use the minimum thickness specified in the scope of the
procedure to calculate a/t. For procedures applied from the outside
surface, the actual thickness of the test specimen is to be used to
calculate a/t.
(C) When applying Supplement 4 to Appendix VIII, the following
conditions must be used:
(1) A depth sizing requirement of 0.15 inch RMS must be used in
lieu of the requirements in Subparagraphs 3.2(a) and 3.2(c), and a
length sizing requirement of 0.75 inch RMS must be used in lieu of the
requirement in Subparagraph 3.2(b).
(2) In lieu of the location acceptance criteria requirements of
Subparagraph 2.1(b), a flaw will be considered detected when reported
within 1.0 inch or 10 percent of the metal path to the flaw, whichever
is greater, of its true location in the X and Y directions.
(3) In lieu of the flaw type requirements of Subparagraph
1.1(e)(1), a minimum of 70 percent of the flaws in the detection and
sizing tests shall be cracks. Notches, if used, must be limited by the
following:
(i) Notches must be limited to the case where examinations are
performed from the clad surface.
(ii) Notches must be semielliptical with a tip width of less than
or equal to 0.010 inches.
[[Page 36273]]
(iii) Notches must be perpendicular to the surface within 2 degrees.
(4) In lieu of the detection test matrix requirements in paragraphs
1.1(e)(2) and 1.1(e)(3), personnel demonstration test sets must contain
a representative distribution of flaw orientations, sizes, and
locations.
(D) The following conditions must be used in addition to the
requirements of Supplement 6 to Appendix VIII:
(1) Paragraph 3.1, Detection Acceptance Criteria--Personnel are
qualified for detection if:
(i) No surface connected flaw greater than 0.25 inch through wall
has been missed.
(ii) No embedded flaw greater than 0.50 inch through wall has been
missed.
(2) Paragraph 3.1, Detection Acceptance Criteria--For procedure
qualification, all flaws within the scope of the procedure are
detected.
(3) Paragraph 1.1(b) for detection and sizing test flaws and
locations--Flaws smaller than the 50 percent of allowable flaw size, as
defined in IWB-3500, need not be included as detection flaws. Flaws
which are less than the allowable flaw size, as defined in IWB-3500,
may be used as detection and sizing flaws.
(4) Notches are not permitted.
(E) When applying Supplement 6 to Appendix VIII, the following
conditions must be used:
(1) A depth sizing requirement of 0.25 inch RMS must be used in
lieu of the requirements of subparagraphs 3.2(a), 3.2(c)(2), and
3.2(c)(3).
(2) In lieu of the location acceptance criteria requirements in
Subparagraph 2.1(b), a flaw will be considered detected when reported
within 1.0 inch or 10 percent of the metal path to the flaw, whichever
is greater, of its true location in the X and Y directions.
(3) In lieu of the length sizing criteria requirements of
Subparagraph 3.2(b), a length sizing acceptance criteria of 0.75 inch
RMS must be used.
(4) In lieu of the detection specimen requirements in Subparagraph
1.1(e)(1), a minimum of 55 percent of the flaws must be cracks. The
remaining flaws may be cracks or fabrication type flaws, such as slag
and lack of fusion. The use of notches is not allowed.
(5) In lieu of paragraphs 1.1(e)(2) and 1.1(e)(3) detection test
matrix, personnel demonstration test sets must contain a representative
distribution of flaw orientations, sizes, and locations.
(F) The following conditions may be used for personnel
qualification for combined Supplement 4 to Appendix VIII and Supplement
6 to Appendix VIII qualification. Licensees choosing to apply this
combined qualification shall apply all of the provisions of Supplements
4 and 6 including the following conditions:
(1) For detection and sizing, the total number of flaws must be at
least 10. A minimum of 5 flaws shall be from Supplement 4, and a
minimum of 50 percent of the flaws must be from Supplement 6. At least
50 percent of the flaws in any sizing must be cracks. Notches are not
acceptable for Supplement 6.
(2) Examination personnel are qualified for detection and length
sizing when the results of any combined performance demonstration
satisfy the acceptance criteria of Supplement 4 to Appendix VIII.
(3) Examination personnel are qualified for depth sizing when
Supplement 4 to Appendix VIII and Supplement 6 to Appendix VIII flaws
are sized within the respective acceptance criteria of those
supplements.
(G) When applying Supplement 4 to Appendix VIII, Supplement 6 to
Appendix VIII, or combined Supplement 4 and Supplement 6 qualification,
the following additional conditions must be used, and examination
coverage must include:
(1) The clad to base metal interface, including a minimum of 15
percent T (measured from the clad to base metal interface), must be
examined from four orthogonal directions using procedures and personnel
qualified in accordance with Supplement 4 to Appendix VIII.
(2) If the clad-to-base-metal-interface procedure demonstrates
detectability of flaws with a tilt angle relative to the weld
centerline of at least 45 degrees, the remainder of the examination
volume is considered fully examined if coverage is obtained in one
parallel and one perpendicular direction. This must be accomplished
using a procedure and personnel qualified for single-side examination
in accordance with Supplement 6. Subsequent examinations of this volume
may be performed using examination techniques qualified for a tilt
angle of at least 10 degrees.
(3) The examination volume not addressed by paragraph
(b)(2)(xv)(G)(1) of this section is considered fully examined if
coverage is obtained in one parallel and one perpendicular direction,
using a procedure and personnel qualified for single sided examination
when the conditions in paragraph (b)(2)(xv)(G)(2) are met.
(H) When applying Supplement 5 to Appendix VIII, at least 50
percent of the flaws in the demonstration test set must be cracks and
the maximum mis-orientation must be demonstrated with cracks. Flaws in
nozzles with bore diameters equal to or less than 4 inches may be
notches.
(I) When applying Supplement 5, Paragraph (a), to Appendix VIII,
the number of false calls allowed must be D/10, with a maximum of 3,
where D is the diameter of the nozzle.
(J) [Reserved]
(K) When performing nozzle-to-vessel weld examinations, the
following conditions must be used when the requirements contained in
Supplement 7 to Appendix VIII are applied for nozzle-to-vessel welds in
conjunction with Supplement 4 to Appendix VIII, Supplement 6 to
Appendix VIII, or combined Supplement 4 and Supplement 6 qualification.
(1) For examination of nozzle-to-vessel welds conducted from the
bore, the following conditions are required to qualify the procedures,
equipment, and personnel:
(i) For detection, a minimum of four flaws in one or more full-
scale nozzle mock-ups must be added to the test set. The specimens must
comply with Supplement 6, paragraph 1.1, to Appendix VIII, except for
flaw locations specified in Table VIII S6-1. Flaws may be notches,
fabrication flaws or cracks. Seventy-five (75) percent of the flaws
must be cracks or fabrication flaws. Flaw locations and orientations
must be selected from the choices shown in paragraph (b)(2)(xi)(K)(4)
of this section, Table VIII-S7-1--Modified, with the exception that
flaws in the outer eighty-five (85) percent of the weld need not be
perpendicular to the weld. There may be no more than two flaws from
each category, and at least one subsurface flaw must be included.
(ii) For length sizing, a minimum of four flaws as in paragraph
(b)(2)(xv)(K)(1)(i) of this section must be included in the test set.
The length sizing results must be added to the results of combined
Supplement 4 to Appendix VIII and Supplement 6 to Appendix VIII. The
combined results must meet the acceptance standards contained in
paragraph (b)(2)(xv)(E)(3) of this section.
(iii) For depth sizing, a minimum of four flaws as in paragraph
(b)(2)(xv)(K)(1)(i) of this section must be included in the test set.
Their depths must be distributed over the ranges of Supplement 4,
Paragraph 1.1, to Appendix VIII, for the inner 15 percent of the wall
thickness and Supplement 6, Paragraph 1.1, to Appendix VIII, for the
remainder of the wall thickness. The depth sizing results must be
combined with the sizing results from Supplement 4 to Appendix VIII for
the inner 15 percent and to Supplement 6 to Appendix VIII for the
remainder of the
[[Page 36274]]
wall thickness. The combined results must meet the depth sizing
acceptance criteria contained in paragraphs (b)(2)(xv)(C)(1),
(b)(2)(xv)(E)(1), and (b)(2)(xv)(F)(3) of this section.
(2) For examination of reactor pressure vessel nozzle-to-vessel
welds conducted from the inside of the vessel,
(i) The clad to base metal interface and the adjacent examination
volume to a minimum depth of 15 percent T (measured from the clad to
base metal interface) must be examined from four orthogonal directions
using a procedure and personnel qualified in accordance with Supplement
4 to Appendix VIII as conditioned by paragraphs (b)(2)(xv)(B) and
(b)(2)(xv)(C) of this section.
(ii) When the examination volume defined in paragraph
(b)(2)(xi)(K)(2)(i) of this section cannot be effectively examined in
all four directions, the examination must be augmented by examination
from the nozzle bore using a procedure and personnel qualified in
accordance with paragraph (b)(2)(xi)(K)(1) of this section.
(iii) The remainder of the examination volume not covered by
paragraph (b)(2)(xv)(K)(2)(ii) of this section or a combination of
paragraphs (b)(2)(xv)(K)(2)(i) and (b)(2)(xv)(K)(2)(ii) of this
section, must be examined from the nozzle bore using a procedure and
personnel qualified in accordance with paragraph (b)(2)(xv)(K)(1) of
this section, or from the vessel shell using a procedure and personnel
qualified for single sided examination in accordance with Supplement 6
to Appendix VIII, as conditioned by paragraphs (b)(2)(xv)(D) through
(b)(2)(xv)(G) of this section.
(3) For examination of reactor pressure vessel nozzle-to-shell
welds conducted from the outside of the vessel,
(i) The clad to base metal interface and the adjacent metal to a
depth of 15 percent T, (measured from the clad to base metal interface)
must be examined from one radial and two opposing circumferential
directions using a procedure and personnel qualified in accordance with
Supplement 4 to Appendix VIII, as conditioned by paragraphs
(b)(2)(xv)(B) and (b)(2)(xv)(C) of this section, for examinations
performed in the radial direction, and Supplement 5 to Appendix VIII,
as conditioned by paragraph (b)(2)(xv)(J) of this section, for
examinations performed in the circumferential direction.
(ii) The examination volume not addressed by paragraph
(b)(2)(xv)(K)(3)(i) of this section must be examined in a minimum of
one radial direction using a procedure and personnel qualified for
single sided examination in accordance with Supplement 6 to Appendix
VIII, as conditioned by paragraphs (b)(2)(xv)(D) through (b)(2)(xv)(G)
of this section.
(4) Table VIII-S7-1, ``Flaw Locations and Orientations,''
Supplement 7 to Appendix VIII, is conditioned as follows:
Table VIII-S7-1--Modified
------------------------------------------------------------------------
Flaw locations and orientations
-------------------------------------------------------------------------
Parallel to Perpendicular
weld to weld
------------------------------------------------------------------------
Inner 15 percent.................... X X
OD Surface.......................... X ................
Subsurface.......................... X ................
------------------------------------------------------------------------
(L) As a condition to the requirements of Supplement 8,
Subparagraph 1.1(c), to Appendix VIII, notches may be located within
one diameter of each end of the bolt or stud.
(M) When implementing Supplement 12 to Appendix VIII, only the
provisions related to the coordinated implementation of Supplement 3 to
Supplement 2 performance demonstrations are to be applied.
(xvi) Appendix VIII single side ferritic vessel and piping and
stainless steel piping examination. When applying editions and addenda
prior to the 2007 Edition of Section XI, the following conditions
apply.
(A) Examinations performed from one side of a ferritic vessel weld
must be conducted with equipment, procedures, and personnel that have
demonstrated proficiency with single side examinations. To demonstrate
equivalency to two sided examinations, the demonstration must be
performed to the requirements of Appendix VIII as conditioned by this
paragraph and paragraphs (b)(2)(xv)(B) through (b)(2)(xv)(G) of this
section, on specimens containing flaws with non-optimum sound energy
reflecting characteristics or flaws similar to those in the vessel
being examined.
(B) Examinations performed from one side of a ferritic or stainless
steel pipe weld must be conducted with equipment, procedures, and
personnel that have demonstrated proficiency with single side
examinations. To demonstrate equivalency to two sided examinations, the
demonstration must be performed to the requirements of Appendix VIII as
conditioned by this paragraph and paragraph (b)(2)(xv)(A) of this
section.
(xvii) Reconciliation of quality requirements. When purchasing
replacement items, in addition to the reconciliation provisions of IWA-
4200, 1995 Addenda through 1998 Edition, the replacement items must be
purchased, to the extent necessary, in accordance with the licensee's
quality assurance program description required by 10 CFR
50.34(b)(6)(ii).
(xviii) Certification of NDE personnel. (A) Level I and II
nondestructive examination personnel shall be recertified on a 3-year
interval in lieu of the 5-year interval specified in the 1997 Addenda
and 1998 Edition of IWA-2314, and IWA-2314(a) and IWA-2314(b) of the
1999 Addenda through the latest edition and addenda incorporated by
reference in paragraph (b)(2) of this section.
(B) When applying editions and addenda prior to the 2007 Edition of
Section XI, paragraph IWA-2316 may only be used to qualify personnel
that observe leakage during system leakage and hydrostatic tests
conducted in accordance with IWA 5211(a) and (b).
(C) When applying editions and addenda prior to the 2005 Addenda of
Section XI, licensee's qualifying visual examination personnel for VT-3
visual examination under paragraph IWA-2317 of Section XI, must
demonstrate the proficiency of the training by administering an initial
qualification examination and administering subsequent examinations on
a 3-year interval.
(xix) Substitution of alternative methods. The provisions for
substituting alternative examination methods, a combination of methods,
or newly developed techniques in the 1997 Addenda of IWA-2240 must be
applied
[[Page 36275]]
when using the 1998 Edition through the 2004 Edition of Section XI of
the ASME B&PV Code. The provisions in IWA-4520(c), 1997 Addenda through
the 2004 Edition, allowing the substitution of alternative methods, a
combination of methods, or newly developed techniques for the methods
specified in the Construction Code are not approved for use. The
provisions in IWA-4520(b)(2) and IWA-4521 of the 2008 Addenda through
the latest edition and addenda approved in paragraph (b)(2) of this
section, allowing the substitution of ultrasonic examination for
radiographic examination specified in the Construction Code are not
approved for use.
(xx) System leakage tests.
(A) When performing system leakage tests in accordance with IWA-
5213(a), 1997 through 2002 Addenda, the licensee shall maintain a 10-
minute hold time after test pressure has been reached for Class 2 and
Class 3 components that are not in use during normal operating
conditions. No hold time is required for the remaining Class 2 and
Class 3 components provided that the system has been in operation for
at least 4 hours for insulated components or 10 minutes for uninsulated
components.
(B) The NDE provision in IWA-4540(a)(2) of the 2002 Addenda of
Section XI must be applied when performing system leakage tests after
repair and replacement activities performed by welding or brazing on a
pressure retaining boundary using the 2003 Addenda through the latest
edition and addenda incorporated by reference in paragraph (b)(2) of
this section.
(xxi) Table IWB-2500-1 examination requirements.
(A) The provisions of Table IWB-2500-1, Examination Category B-D,
Full Penetration Welded Nozzles in Vessels, Items B3.40 and B3.60
(Inspection Program A) and Items B3.120 and B3.140 (Inspection Program
B) of the 1998 Edition must be applied when using the 1999 Addenda
through the latest edition and addenda incorporated by reference in
paragraph (b)(2) of this section. A visual examination with
magnification that has a resolution sensitivity to detect a 1-mil width
wire or crack, utilizing the allowable flaw length criteria in Table
IWB-3512-1, 1997 Addenda through the latest edition and addenda
incorporated by reference in paragraph (b)(2) of this section, with a
limiting assumption on the flaw aspect ratio (i.e., a/l = 0.5), may be
performed instead of an ultrasonic examination.
(B) [Reserved]
(xxii) Surface examination. The use of the provision in IWA-2220,
``Surface Examination,'' of Section XI, 2001 Edition through the latest
edition and addenda incorporated by reference in paragraph (b)(2) of
this section, that allow use of an ultrasonic examination method is
prohibited.
(xxiii) Evaluation of thermally cut surfaces. The use of the
provisions for eliminating mechanical processing of thermally cut
surfaces in IWA-4461.4.2 of Section XI, 2001 Edition through the latest
edition and addenda incorporated by reference in paragraph (b)(2) of
this section are prohibited.
(xxiv) Incorporation of the performance demonstration initiative
and addition of ultrasonic examination criteria. The use of Appendix
VIII and the supplements to Appendix VIII and Article I-3000 of Section
XI of the ASME B&PV Code, 2002 Addenda through the 2006 Addenda is
prohibited.
(xxv) Mitigation of defects by modification. The use of the
provisions in IWA-4340, ``Mitigation of Defects by Modification,''
Section XI, 2001 Edition through the latest edition and addenda
incorporated by reference in paragraph (b)(2) of this section are
prohibited.
(xxvi) Pressure testing Class 1, 2, and 3 mechanical joints. The
repair and replacement activity provisions in IWA-4540(c) of the 1998
Edition of Section XI for pressure testing Class 1, 2, and 3 mechanical
joints must be applied when using the 2001 Edition through the latest
edition and addenda incorporated by reference in paragraph (b)(2) of
this section.
(xxvii) Removal of insulation. When performing visual examination
in accordance with IWA-5242 of Section XI of the ASME B&PV Code, 2003
Addenda through the 2006 Addenda, or IWA-5241 of the 2007 Edition
through the latest edition and addenda incorporated in paragraph (b)(2)
of this section, insulation must be removed from 17-4 PH or 410
stainless steel studs or bolts aged at a temperature below 1100 [deg]F
or having a Rockwell Method C hardness value above 30, and from A-286
stainless steel studs or bolts preloaded to 100,000 pounds per square
inch or higher.
(xxviii) Analysis of flaws. Licensees using ASME B&PV Code, Section
XI, Appendix A shall use the following conditions when implementing
Equation (2) in A-4300(b)(1):
For R < 0, [Delta]KI depends on the crack depth (a), and
the flow stress ([sigma]f). The flow stress is defined by
[sigma]f = \1/2\([sigma]ys +
[sigma]ult), where [sigma]ys is the yield
strength and [sigma]ult is the ultimate tensile strength in
units ksi (MPa) and a is in units in. (mm). For -2 <= R <= 0 and
Kmax - Kmin <= 0.8 x 1.12 [sigma]f
[radic]([pi]a), S = 1 and [Delta]KI = Kmax. For R
< -2 and Kmax - Kmin <= 0.8 x 1.12
[sigma]f [radic]([pi]a), S = 1 and [Delta]KI = (1
- R) Kmax/3. For R < 0 and Kmax - Kmin
> 0.8 x 1.12 [sigma]f [radic]([pi]a), S = 1 and
[Delta]KI = Kmax - Kmin.
(xxix) Nonmandatory Appendix R. Nonmandatory Appendix R, ``Risk-
Informed Inspection Requirements for Piping,'' of Section XI, 2005
Addenda through the latest edition and addenda incorporated by
reference in paragraph (b)(2) of this section, may not be implemented
without prior NRC authorization of the proposed alternative in
accordance with paragraph (a)(3)(i) of this section.
(3) As used in this section, references to the OM Code refer to the
ASME Code for Operation and Maintenance of Nuclear Power Plants,
Subsections ISTA, ISTB, ISTC, and ISTD, Mandatory Appendices I and II,
and Nonmandatory Appendices A through H and J, and include the 1995
Edition through the 2006 Addenda subject to the following conditions:
* * * * *
(v) Subsection ISTD. Article IWF-5000, ``Inservice Inspection
Requirements for Snubbers,'' of the ASME B&PV Code, Section XI, must be
used when performing inservice inspection examinations and tests of
snubbers at nuclear power plants, except as conditioned in paragraphs
(b)(3)(v)(A) and (b)(3)(v)(B) of this section.
(A) Licensees may use Subsection ISTD, ``Preservice and Inservice
Examination and Testing of Dynamic Restraints (Snubbers) in Light-Water
Reactor Power Plants,'' ASME OM Code, 1995 Edition through the latest
edition and addenda incorporated by reference in paragraph (b)(2) of
this section, in place of the requirements for snubbers in the editions
and addenda up to the 2005 Addenda of the ASME B&PV Code, Section XI,
IWF-5200(a) and (b) and IWF-5300(a) and (b), by making appropriate
changes to their technical specifications or licensee-controlled
documents. Preservice and inservice examinations must be performed
using the VT-3 visual examination method described in IWA-2213.
(B) Licensees shall comply with the provisions for examining and
testing snubbers in Subsection ISTD of the ASME OM Code and make
appropriate changes to their technical specifications or licensee-
controlled documents when using the 2006 Addenda and later editions and
addenda of Section XI of the ASME B&PV Code.
(vi) Exercise interval for manual valves. Manual valves must be
exercised on a 2-year interval rather that the 5-
[[Page 36276]]
year interval specified in paragraph ISTC-3540 of the 1999 through the
2005 Addenda of the ASME OM Code, provided that adverse conditions do
not require more frequent testing.
* * * * *
(c) * * *
(3) The Code edition, addenda, and optional ASME Code cases to be
applied to components of the reactor coolant pressure boundary must be
determined by the provisions of paragraph NCA-1140, Subsection NCA of
Section III of the ASME Boiler and Pressure Vessel Code, subject to the
following conditions:
(i) The edition and addenda applied to a component must be those
which are incorporated by reference in paragraph (b)(1) of this
section;
(ii) The ASME Code provisions applied to the pressure vessel may be
dated no earlier than the Summer 1972 Addenda of the 1971 edition;
(iii) The ASME Code provisions applied to piping, pumps, and valves
may be dated no earlier than the Winter 1972 Addenda of the 1971
edition; and
(iv) The optional Code cases applied to a component must be those
listed in NRC Regulatory Guide 1.84 that is incorporated by reference
in paragraph (b) of this section.
* * * * *
(d) * * *
(2) The Code edition, addenda, and optional ASME Code cases to be
applied to the systems and components identified in paragraph (d)(1) of
this section must be determined by the rules of paragraph NCA-1140,
Subsection NCA of Section III of the ASME Boiler and Pressure Vessel
Code, subject to the following conditions:
(i) The edition and addenda must be those which are incorporated by
reference in paragraph (b)(1) of this section;
(ii) The ASME Code provisions applied to the systems and components
may be dated no earlier than the 1980 Edition; and
(iii) The optional Code cases must be those listed in the NRC
Regulatory Guide 1.84 that is incorporated by reference in paragraph
(b) of this section.
(e) * * *
(2) The Code edition, addenda, and optional ASME Code cases to be
applied to the systems and components identified in paragraph (e)(1) of
this section must be determined by the rules of paragraph NCA-1140,
subsection NCA of Section III of the ASME Boiler and Pressure Vessel
Code, subject to the following conditions:
(i) The edition and addenda must be those which are incorporated by
reference in paragraph (b)(1) of this section;
(ii) The ASME Code provisions applied to the systems and components
may be dated no earlier than the 1980 Edition; and
(iii) The optional Code cases must be those listed in NRC
Regulatory Guide 1.84 that is incorporated by reference in paragraph
(b) of this section.
(f) * * *
(2) For a boiling or pressurized water-cooled nuclear power
facility whose construction permit was issued on or after January 1,
1971, but before July 1, 1974, pumps and valves which are classified as
ASME Code Class 1 and Class 2 must be designed and provided with access
to enable the performance of inservice tests for operational readiness
set forth in editions and addenda of Section XI of the ASME Boiler and
Pressure Vessel Code incorporated by reference in paragraph (b) of this
section (or the optional ASME Code cases listed in NRC Regulatory Guide
1.147, Revision 16, or Regulatory Guide 1.192 that are incorporated by
reference in paragraph (b) of this section) in effect 6 months before
the date of issuance of the construction permit. The pumps and valves
may meet the inservice test requirements set forth in subsequent
editions of this Code and addenda which are incorporated by reference
in paragraph (b) of this section (or the optional ASME Code Cases
listed in NRC Regulatory Guide 1.147, Revision 16, or Regulatory Guide
1.192 that are incorporated by reference in paragraph (b) of this
section), subject to the applicable conditions listed therein.
(3) * * *
(v) All pumps and valves may meet the test requirements set forth
in subsequent editions of codes and addenda or portions thereof which
are incorporated by reference in paragraph (b) of this section, subject
to the conditions listed in paragraph (b) of this section.
(4) Throughout the service life of a boiling or pressurized water-
cooled nuclear power facility, pumps and valves which are classified as
ASME Code Class 1, Class 2, and Class 3 must meet the inservice test
requirements, except design and access provisions, set forth in the
ASME OM Code and addenda that become effective subsequent to editions
and addenda specified in paragraphs (f)(2) and (f)(3) of this section
and that are incorporated by reference in paragraph (b) of this
section, to the extent practical within the limitations of design,
geometry and materials of construction of the components.
(i) Inservice tests to verify operational readiness of pumps and
valves, whose function is required for safety, conducted during the
initial 120-month interval must comply with the requirements in the
latest edition and addenda of the Code incorporated by reference in
paragraph (b) of this section on the date 12 months before the date of
issuance of the operating license under this part, or 12 months before
the date scheduled for initial loading fuel under a combined license
under part 52 of this chapter (or the optional ASME Code cases listed
in NRC Regulatory Guide 1.192, that is incorporated by reference in
paragraph (b) of this section), subject to the conditions listed in
paragraph (b) of this section.
(ii) Inservice tests to verify operational readiness of pumps and
valves, whose function is required for safety, conducted during
successive 120-month intervals must comply with the requirements of the
latest edition and addenda of the Code incorporated by reference in
paragraph (b) of this section 12 months before the start of the 120-
month interval (or the optional ASME Code cases listed in NRC
Regulatory Guide 1.147, Revision 16, or Regulatory Guide 1.192 that are
incorporated by reference in paragraph (b) of this section), subject to
the conditions listed in paragraph (b) of this section.
(iii) [Reserved]
(iv) Inservice tests of pumps and valves may meet the requirements
set forth in subsequent editions and addenda that are incorporated by
reference in paragraph (b) of this section, subject to the conditions
listed in paragraph (b) of this section, and subject to NRC approval.
Portions of editions or addenda may be used provided that all related
requirements of the respective editions or addenda are met.
(5) * * *
(iv) Where a pump or valve test requirement by the code or addenda
is determined to be impractical by the licensee and is not included in
the revised inservice test program as permitted by paragraph (f)(4) of
this section, the basis for this determination must be submitted for
NRC review and approval not later than 12 months after the expiration
of the initial 120-month interval of operation from start of facility
commercial operation and each subsequent 120-month interval of
operation during which the test is determined to be impractical.
* * * * *
(g) * * *
(2) For a boiling or pressurized water-cooled nuclear power
facility whose
[[Page 36277]]
construction permit was issued on or after January 1, 1971, but before
July 1, 1974, components (including supports) which are classified as
ASME Code Class 1 and Class 2 must be designed and be provided with
access to enable the performance of inservice examination of such
components (including supports) and must meet the preservice
examination requirements set forth in editions and addenda of Section
III or Section XI of the ASME B&PV Code (or ASME OM Code for snubber
examination and testing) incorporated by reference in paragraph (b) of
this section (or the optional ASME code cases listed in NRC Regulatory
Guide 1.147, Revision 16, that are incorporated by reference in
paragraph (b) of this section) in effect six months before the date of
issuance of the construction permit. The components (including
supports) may meet the requirements set forth in subsequent editions
and addenda of this Code which are incorporated by reference in
paragraph (b) of this section (or the optional ASME code cases listed
in NRC Regulatory Guide 1.147, Revision 16, when using Section XI, or
Regulatory Guide 1.192 when using the OM Code, that are incorporated by
reference in paragraph (b) of this section), subject to the applicable
conditions.
(3) For a boiling or pressurized water-cooled nuclear power
facility whose construction permit under this part, or design
certification, design approval, combined license, or manufacturing
license under part 52 of this chapter, was issued on or after July 1,
1974:
(i) Components (including supports) which are classified as ASME
Code Class 1 must be designed and provided with access to enable the
performance of inservice examination of these components and must meet
the preservice examination requirements set forth in the editions and
addenda of Section III or Section XI of the ASME B&PV Code (or ASME OM
Code for snubber examination and testing) incorporated by reference in
paragraph (b) of this section (or the optional ASME code cases listed
in NRC Regulatory Guide 1.147, Revision 16, when using Section XI, or
Regulatory Guide 1.192 when using the OM Code, that are incorporated by
reference in paragraph (b) of this section) applied to the construction
of the particular component.
(ii) Components which are classified as ASME Code Class 2 and Class
3 and supports for components which are classified as ASME Code Class
1, Class 2, and Class 3 must be designed and be provided with access to
enable the performance of inservice examination of these components and
must meet the preservice examination requirements set forth in the
editions and addenda of Section III or Section XI of the ASME B&PV Code
(or ASME OM Code for snubber examination and testing) incorporated by
reference in paragraph (b) of this section (or the optional ASME code
cases listed in NRC Regulatory Guide 1.147, Revision 16, when using
Section XI; or Regulatory Guide 1.192 when using the OM Code, that are
incorporated by reference in paragraph (b) of this section) applied to
the construction of the particular component.
(iii)-(iv) [Reserved]
(v) All components (including supports) may meet the requirements
set forth in subsequent editions of codes and addenda or portions
thereof which are incorporated by reference in paragraph (b) of this
section, subject to the conditions listed therein.
(4) Throughout the service life of a boiling or pressurized water-
cooled nuclear power facility, components (including supports) which
are classified as ASME Code Class 1, Class 2, and Class 3 must meet the
requirements, except design and access provisions and preservice
examination requirements, set forth in Section XI of editions and
addenda of the ASME B&PV Code (or ASME OM Code for snubber examination
and testing) that become effective subsequent to editions specified in
paragraphs (g)(2) and (g)(3) of this section and that are incorporated
by reference in paragraph (b) of this section, to the extent practical
within the limitations of design, geometry and materials of
construction of the components. Components which are classified as
Class MC pressure retaining components and their integral attachments,
and components which are classified as Class CC pressure retaining
components and their integral attachments must meet the requirements,
except design and access provisions and preservice examination
requirements, set forth in Section XI of the ASME B&PV Code and addenda
that are incorporated by reference in paragraph (b) of this section,
subject to the condition listed in paragraph (b)(2)(vi) of this section
and the conditions listed in paragraphs (b)(2)(viii) and (b)(2)(ix) of
this section, to the extent practical within the limitation of design,
geometry and materials of construction of the components.
(i) Inservice examinations of components and system pressure tests
conducted during the initial 120-month inspection interval must comply
with the requirements in the latest edition and addenda of the Code
incorporated by reference in paragraph (b) of this section on the date
12 months before the date of issuance of the operating license under
this part, or 12 months before the date scheduled for initial loading
of fuel under a combined license under part 52 of this chapter (or the
optional ASME Code cases listed in NRC Regulatory Guide 1.147, through
Revision 16, when using Section XI; or Regulatory Guide 1.192 when
using the OM Code, that are incorporated by reference in paragraph (b)
of this section), subject to the conditions listed in paragraph (b) of
this section.
(ii) Inservice examination of components and system pressure tests
conducted during successive 120-month inspection intervals must comply
with the requirements of the latest edition and addenda of the Code
incorporated by reference in paragraph (b) of this section 12 months
before the start of the 120-month inspection interval (or the optional
ASME Code cases listed in NRC Regulatory Guide 1.147, Revision 16, that
are incorporated by reference in paragraph (b) of this section),
subject to the conditions listed in paragraph (b) of this section.
However, a licensee whose inservice inspection interval commences
during the 12 through 18-month period after July 21, 2011 may delay the
update of their Appendix VIII program by up to 18 months after July 21,
2011.
(iii) When applying editions and addenda prior to the 2003 Addenda
of Section XI of the ASME B&PV Code licensees may, but are not required
to, perform the surface examinations of high-pressure safety injection
systems specified in Table IWB-2500-1, Examination Category B-J, Item
Numbers B9.20, B9.21 and B9.22.
(iv) Inservice examination of components and system pressure tests
may meet the requirements set forth in subsequent editions and addenda
that are incorporated by reference in paragraph (b) of this section,
subject to the conditions listed in paragraph (b) of this section, and
subject to Commission approval. Portions of editions or addenda may be
used provided that all related requirements of the respective editions
or addenda are met.
(v) For a boiling or pressurized water-cooled nuclear power
facility whose construction permit under this part or combined license
under part 52 of this chapter was issued after January 1, 1956:
(A) Metal containment pressure retaining components and their
integral attachments must meet the inservice inspection, repair, and
replacement requirements applicable to components
[[Page 36278]]
which are classified as ASME Code Class MC;
(B) Metallic shell and penetration liners which are pressure
retaining components and their integral attachments in concrete
containments must meet the inservice inspection, repair, and
replacement requirements applicable to components which are classified
as ASME Code Class MC; and
(C) Concrete containment pressure retaining components and their
integral attachments, and the post-tensioning systems of concrete
containments must meet the inservice inspections, repair, and
replacement requirements applicable to components which are classified
as ASME Code Class CC.
(5) * * *
(iii) If the licensee has determined that conformance with a code
requirement is impractical for its facility, the licensee shall notify
the NRC and submit, as specified in Sec. 50.4, information to support
the determinations. Determinations of impracticality in accordance with
this section must be based on the demonstrated limitations experienced
when attempting to comply with the code requirements during the
inservice inspection interval for which the request is being submitted.
Requests for relief made in accordance with this section must be
submitted to the NRC no later than 12 months after the expiration of
the initial or subsequent 120-month inspection interval for which
relief is sought.
(iv) Where the licensee determines that an examination required by
Code edition or addenda is impractical, the basis for this
determination must be submitted for NRC review and approval not later
than 12 months after the expiration of the initial or subsequent 120-
month inspection interval for which relief is sought.
(6) * * *
(ii) * * *
(B) Licensees do not have to submit to the NRC for approval of
their containment inservice inspection programs which were developed to
satisfy the requirements of Subsection IWE and Subsection IWL with
specified conditions. The program elements and the required
documentation must be maintained on site for audit.
* * * * *
(E) * * *
(1) All licensees of pressurized water reactors shall augment their
inservice inspection program by implementing ASME Code Case N-722-1
subject to the conditions specified in paragraphs (g)(6)(ii)(E)(2)
through (g)(6)(ii)(E)(4) of this section. The inspection requirements
of ASME Code Case N-722-1 do not apply to components with pressure
retaining welds fabricated with Alloy 600/82/182 materials that have
been mitigated by weld overlay or stress improvement.
(2) If a visual examination determines that leakage is occurring
from a specific item listed in Table 1 of ASME Code Case N-722-1 that
is not exempted by the ASME Code, Section XI, IWB-1220(b)(1),
additional actions must be performed to characterize the location,
orientation, and length of crack(s) in Alloy 600 nozzle wrought
material and location, orientation, and length of crack(s) in Alloy 82/
182 butt welds. Alternatively, licensees may replace the Alloy 600/82/
182 materials in all the components under the item number of the
leaking component.
(3) If the actions in paragraph (g)(6)(ii)(E)(2) of this section
determine that a flaw is circumferentially oriented and potentially a
result of primary water stress corrosion cracking, licensees shall
perform non-visual NDE inspections of components that fall under that
ASME Code Case N-722-1 item number. The number of components inspected
must equal or exceed the number of components found to be leaking under
that item number. If circumferential cracking is identified in the
sample, non-visual NDE must be performed in the remaining components
under that item number.
* * * * *
(F) Examination requirements for class 1 piping and nozzle
dissimilar-metal butt welds.
(1) Licensees of existing, operating pressurized-water reactors as
of July 21, 2011 shall implement the requirements of ASME Code Case N-
770-1, subject to the conditions specified in paragraphs
(g)(6)(ii)(F)(2) through (g)(6)(ii)(F)(10) of this section, by the
first refueling outage after August 22, 2011.
(2) Full structural weld overlays authorized by the NRC staff may
be categorized as Inspection Items C or F, as appropriate; welds that
have been mitigated by the Mechanical Stress Improvement Process
(MSIP\TM\) may be categorized as Inspection Items D or E, as
appropriate, provided the criteria in Appendix I of the code case have
been met; for ISI frequencies, all other butt welds that rely on Alloy
82/182 for structural integrity shall be categorized as Inspection
Items A-1, A-2 or B until the NRC staff has reviewed the mitigation and
authorized an alternative code case Inspection Item for the mitigated
weld, or until an alternative code case Inspection Item is used based
on conformance with an ASME mitigation code case endorsed in Regulatory
Guide 1.147 with conditions, if applicable, and incorporated in this
section.
(3) Baseline examinations for welds in Table 1, Inspection Items A-
1, A-2, and B, shall be completed by the end of the next refueling
outage after January 20, 2012. Previous examinations of these welds can
be credited for baseline examinations if they were performed within the
re-inspection period for the weld item in Table 1 using Section XI,
Appendix VIII requirements and met the Code required examination volume
of essentially 100 percent. Other previous examinations that do not
meet these requirements can be used to meet the baseline examination
requirement, provided NRC approval of alternative inspection
requirements in accordance with paragraphs (a)(3)(i) or (a)(3)(ii) of
this section is granted prior to the end of the next refueling outage
after January 20, 2012.
(4) The axial examination coverage requirements of -2500(c) may not
be considered to be satisfied unless essentially 100 percent coverage
is achieved.
(5) All hot-leg operating temperature welds in Inspection Items G,
H, J, and K must be inspected each interval. A 25-percent sample of
cold-leg operating temperature welds must be inspected whenever the
core barrel is removed (unless it has already been inspected within the
past 10 years) or has reached 20 years, whichever is less.
(6) For any mitigated weld whose volumetric examination detects
growth of existing flaws in the required examination volume that exceed
the previous IWB-3600 flaw evaluations or new flaws, a report
summarizing the evaluation, along with inputs, methodologies,
assumptions, and cause of the new flaw or flaw growth is to be provided
to the NRC prior to the weld being placed in service other than modes 5
or 6.
(7) For Inspection Items G, H, J, and K, when applying the
acceptance standards of ASME B&PV Code, Section XI, IWB-3514, for
planar flaws contained within the inlay or onlay, the thickness ``t''
in IWB-3514 is the thickness of the inlay or onlay. For planar flaws in
the balance of the dissimilar metal weld examination volume, the
thickness ``t'' in IWB-3514 is the combined thickness of the inlay or
onlay and the dissimilar metal weld.
(8) Welds mitigated by optimized weld overlays in Inspection Items
D and E are not permitted to be placed into a population to be examined
on a sample basis and must be examined once each inspection interval.
[[Page 36279]]
(9) Replace the first two sentences of Extent and Frequency of
Examination for Inspection Item D in Table 1 of Code Case N-770-1 with,
``Examine all welds no sooner than the third refueling outage and no
later than 10 years following stress improvement application.'' Replace
the first two sentences of Note (11)(b)(2) in Code Case N-770-1 with,
``The first examination following weld inlay, onlay, weld overlay, or
stress improvement for Inspection Items D through K shall be performed
as specified.''
(10) Note (2) to Figure 5(a) of Code Case N-770-1 pertaining to
alternative examination volume for optimized weld overlays may not be
applied unless NRC approval is authorized under paragraphs (a)(3)(i) or
(a)(3)(ii) of this section.
* * * * *
Footnotes to Sec. 50.55a:
\1\ For inspections to be conducted once per interval, the
inspections shall be performed in accordance with the schedule in
Section XI, paragraph IWB-2400, except for plants with inservice
inspection programs based on a Section XI edition or addenda prior
to the 1994 Addenda. For plants with inservice inspection programs
based on a Section XI edition or addenda prior to the 1994 Addenda,
the inspection shall be performed in accordance with the schedule in
Section XI, paragraph IWB-2400, of the 1994 Addenda.
* * * * *
Dated at Rockville, Maryland, this 27th day of May 2011.
For the Nuclear Regulatory Commission.
Eric J. Leeds,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2011-14652 Filed 6-20-11; 8:45 am]
BILLING CODE 7590-01-P