[Federal Register Volume 86, Number 20 (Tuesday, February 2, 2021)]
[Proposed Rules]
[Pages 7820-7838]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-00890]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
[NRC-2017-0025]
RIN 3150-AJ94
Approval of American Society of Mechanical Engineers' Code Cases
AGENCY: Nuclear Regulatory Commission.
ACTION: Proposed rule.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is proposing to
amend its regulations to incorporate by reference proposed revisions of
three regulatory guides, which would approve new, revised, and
reaffirmed Code Cases published by the American Society of Mechanical
Engineers. The NRC is also incorporating by reference one NRC NUREG
associated with a proposed condition on one of the regulatory guides.
This proposed action would allow nuclear power plant licensees, and
applicants for construction permits, operating licenses, combined
licenses, standard design certifications, standard design approvals and
manufacturing licenses, to use the Code Cases listed in these draft
regulatory guides as voluntary alternatives to engineering standards
for the construction, inservice inspection, and inservice testing of
nuclear power plant components. The NRC is requesting comments on this
proposed rule and on the draft versions of the three regulatory guides
proposed to be incorporated by reference. The NRC is also making
available a related draft regulatory guide that lists Code Cases that
the NRC has not approved for use. This draft regulatory guide will not
be incorporated by reference into the NRC's regulations.
DATES: Submit comments on the proposed rule, documents to be
incorporated by reference, and related guidance by April 5, 2021.
Submit comments specific to the information
[[Page 7821]]
collections aspects of this rule by March 4, 2021. Comments received
after these dates will be considered if it is practical to do so, but
the NRC is able to ensure consideration only of comments received on or
before these dates.
ADDRESSES: You may submit comments on the proposed rule, documents to
be incorporated by reference, and related guidance by any of the
following methods (unless this document describes a different method
for submitting comments on a specific subject):
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025. Address
questions about NRC dockets to Dawn Forder; telephone: 301-415-3407;
email: [email protected]. For technical questions contact the
individuals listed in the FOR FURTHER INFORMATION CONTACT section of
this document.
Email comments to: [email protected]. If you do
not receive an automatic email reply confirming receipt, then contact
us at 301-415-1677.
Mail comments to: Secretary, U.S. Nuclear Regulatory
Commission, Washington, DC 20555-0001, ATTN: Rulemakings and
Adjudications Staff.
For additional direction on obtaining information and submitting
comments, see ``Obtaining Information and Submitting Comments'' in the
SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Juan Lopez, Office of Nuclear Material
Safety and Safeguards; telephone: 301-415-2338; email:
[email protected]; or Bruce Lin, Office of Nuclear Regulatory
Research; telephone: 301-415-2446; email: [email protected]. Both are
staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001.
SUPPLEMENTARY INFORMATION:
Executive Summary
A. Need for the Regulatory Action
The purpose of this regulatory action is to incorporate by
reference into the NRC's regulations the latest revisions of three
regulatory guides (RGs) (currently in draft form for comment). This
regulatory action is also incorporating by reference one NRC report,
NUREG-2228, that is associated with a proposed conditon in one of the
regulatory guides. NUREG-2228 was published for public comment on
September 13, 2018 (83 FR 46524). The three draft RGs identify new,
revised, and reaffirmed Code Cases published by the American Society of
Mechanical Engineers (ASME), which the NRC has determined are
acceptable for use as voluntary alternatives to compliance with certain
provisions of the ASME Boiler and Pressure Vessel Code (BPV Code) and
the ASME Code for Operation and Maintenance of Nuclear Power Plants (OM
Code) currently incorporated by reference into the NRC's regulations.
B. Major Provisions
The three draft RGs that the NRC proposes to incorporate by
reference are RG 1.84, ``Design, Fabrication, and Materials Code Case
Acceptability, ASME Section III,'' Revision 39 (Draft Regulatory Guide
(DG)-1366); RG 1.147, ``Inservice Inspection Code Case Acceptability,
ASME Section XI, Division 1,'' Revision 20 (DG-1367); and RG 1.192,
``Operation and Maintenance [OM] Code Case Acceptability, ASME OM
Code,'' Revision 4 (DG-1368). The NRC also proposes to incorporate by
reference NUREG-2228, ``Weld Residual Stress Finite Element Analysis
Validation: Part II--Proposed Validation Procedure,'' which provides
the procedure for validating the weld residual stress analysis
methodology associated with ASME Code Case N-847. This proposed action
would allow nuclear power plant licensees and applicants for
construction permits, operating licenses, combined licenses, standard
design certifications, standard design approvals, and manufacturing
licenses to use the Code Cases newly listed in these revised RGs as
voluntary alternatives to engineering standards for the construction,
inservice inspections, and inservice testing of nuclear power plant
components. The NRC also notes the availability of a proposed version
of RG 1.193, ``ASME Code Cases Not Approved for Use,'' Revision 7 (DG-
1369). This document lists Code Cases that the NRC has not approved for
generic use and will not be incorporated by reference into the NRC's
regulations.
The NRC prepared a draft regulatory analysis to determine the
expected quantitative costs and benefits of this proposed rule, as well
as qualitative factors to be considered in the NRC's rulemaking
decision. The analysis concluded that this proposed rule would result
in net savings to the industry and the NRC. As shown in Table 1, the
estimated total net benefit relative to the regulatory baseline and the
quantitative benefits outweigh the costs by a range from approximately
$5.19 million (7-percent net present value) to $6.20 million (3-percent
net present value).
Table 1--Cost Benefit Summary
----------------------------------------------------------------------------------------------------------------
Total averted costs (costs)
-----------------------------------------------
Attribute 7% Net present 3% Net present
Undiscounted value value
----------------------------------------------------------------------------------------------------------------
Industry Implementation......................................... $0 $0 $0
Industry Operation.............................................. 5,100,000 3,790,000 4,470,000
-----------------------------------------------
Total Industry Costs........................................ 5,100,000 3,790,000 4,470,000
NRC Implementation.............................................. (430,000) (420,000) (420,000)
NRC Operation................................................... 2,460,000 1,820,000 2,150,000
-----------------------------------------------
Total NRC Costs............................................. 2,030,000 1,400,000 1,730,000
-----------------------------------------------
Net..................................................... 7,130,000 5,190,000 6,200,000
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The regulatory analysis also considered the following qualitative
considerations: (1) Flexibility and decreased uncertainty for licensees
when making modifications or preparing to perform inservice inspection
or inservice testing; (2) consistency with the provisions of the
National Technology Transfer and Advancement Act of 1995, which
encourages Federal regulatory agencies to consider adopting voluntary
[[Page 7822]]
consensus standards as an alternative to de novo agency development of
standards affecting an industry; (3) consistency with the NRC's policy
of evaluating the latest versions of consensus standards in terms of
their suitability for endorsement by regulations and regulatory guides;
and (4) consistency with the NRC's goal to harmonize with international
standards to improve regulatory efficiency for both the NRC and
international standards groups.
The draft regulatory analysis concludes that this proposed rule
should be adopted because it is justified when integrating the cost-
beneficial quantitative results and the positive and supporting
nonquantitative considerations in the decision. For more information,
please see the regulatory analysis (Agencywide Documents Access and
Management System (ADAMS) Accession No. ML20133K152).
Table of Contents
I. Obtaining Information and Submitting Comments
A. Obtaining Information
B. Submitting Comments
II. Background
III. Discussion
A. Code Cases Proposed To Be Approved for Unconditional Use
B. Code Cases Proposed To Be Approved for Use With Conditions
1. ASME BPV Code, Section III Code Cases (DG-1366/RG 1.84)
2. ASME BPV Code, Section XI Code Cases (DG-1367/RG 1.147)
3. OM Code Cases (DG-1368/RG 1.192)
C. ASME Code Cases Not Approved for Use (DG-1369/RG 1.193)
IV. Section-by-Section Analysis
V. Regulatory Flexibility Certification
VI. Regulatory Analysis
VII. Backfitting and Issue Finality
VIII. Plain Writing
IX. Environmental Assessment and Proposed Finding of No Significant
Environmental Impact
X. Paperwork Reduction Act Statement
XI. Voluntary Consensus Standards
XII. Incorporation by Reference--Reasonable Availability to
Interested Parties
XIII. Availability of Documents
I. Obtaining Information and Submitting Comments
A. Obtaining Information
Please refer to Docket ID NRC-2017-0025 when contacting the NRC
about the availability of information for this action. You may obtain
publicly-available information related to this action by any of the
following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025.
NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly-available documents online in the
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS,
please contact the NRC's Public Document Room (PDR) reference staff at
1-800-397-4209, 301-415-4737, or by email to [email protected]. For
the convenience of the reader, instructions about obtaining materials
referenced in this document are provided in the ``Availability of
Documents'' section.
Attention: The PDR, where you may examine and order copies
of public documents is currently closed. You may submit your request to
the PDR via email at [email protected] or call 1-800-397-4209
between 8:00 a.m. and 4:00 p.m. (EST), Monday through Friday, except
Federal holidays.
B. Submitting Comments
Please include Docket ID NRC-2017-0025 in your comment submission.
The NRC cautions you not to include identifying or contact
information that you do not want to be publicly disclosed in your
comment submission. The NRC will post all comment submissions at
https://www.regulations.gov as well as enter the comment submissions
into ADAMS. The NRC does not routinely edit comment submissions to
remove identifying or contact information.
If you are requesting or aggregating comments from other persons
for submission to the NRC, then you should inform those persons not to
include identifying or contact information that they do not want to be
publicly disclosed in their comment submission. Your request should
state that the NRC does not routinely edit comment submissions to
remove such information before making the comment submissions available
to the public or entering the comment into ADAMS.
II. Background
The ASME develops and publishes the ASME BPV Code, which contains
requirements for the design, construction, and inservice inspection
examination of nuclear power plant components, and the ASME OM Code,\1\
which contains requirements for inservice testing of nuclear power
plant components. In response to BPV and OM Code user requests, the
ASME develops Code Cases that provide voluntary alternatives to BPV and
OM Code requirements under special circumstances.
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\1\ The editions and addenda of the ASME Code for Operation and
Maintenance of Nuclear Power Plants have had different titles from
2005 to 2017, and are referred to as the ``OM Code'' collectively in
this rule.
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The NRC approves the ASME BPV and OM Codes in Sec. 50.55a, ``Codes
and standards,'' of title 10 of the Code of Federal Regulations (10
CFR) through the process of incorporation by reference. As such, each
provision of the ASME Codes incorporated by reference into and mandated
by Sec. 50.55a constitutes a legally-binding NRC requirement imposed
by rule. As noted previously, the ASME Code Cases, for the most part,
represent alternative approaches for complying with provisions of the
ASME BPV and OM Codes. Accordingly, the NRC periodically amends Sec.
50.55a to incorporate by reference the NRC's RGs listing approved ASME
Code Cases that may be used as voluntary alternatives to the BPV and OM
Codes.\2\
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\2\ See Federal Register final rule, ``Incorporation by
Reference of ASME BPV and OM Code Cases'' (68 FR 40469; July 8,
2003).
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This proposed rule is the latest in a series of rules that
incorporate by reference new versions of several RGs identifying new,
revised, and reaffirmed,\3\ and unconditionally or conditionally
acceptable ASME Code Cases that the NRC approves for use. In developing
these RGs, the NRC reviews the ASME BPV and OM Code Cases, determines
the acceptability of each Code Case, and publishes its findings in the
RGs. The RGs are revised periodically as new Code Cases are published
by the ASME. The NRC incorporates by reference the RGs listing
acceptable and conditionally acceptable ASME Code Cases into Sec.
50.55a. The NRC published a final rule dated March 16, 2020 (85 FR
14736) that incorporated by reference into Sec. 50.55a the most recent
versions of the RGs, which are: RG 1.84, ``Design, Fabrication, and
Materials Code Case Acceptability, ASME Section III,'' Revision 38; RG
1.147, ``Inservice Inspection Code Case Acceptability, ASME Section XI,
Division 1,'' Revision 19; and RG 1.192, ``Operation and Maintenance
Code Case Acceptability, ASME OM Code,'' Revision 3.
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\3\ Code Cases are categorized by the ASME as one of three
types: new, revised, or reaffirmed. A new Code Case provides for a
new alternative to specific the ASME Code provisions or addresses a
new need. The ASME defines a revised Code Case to be a revision
(modification) to an existing Code Case to address, for example,
technological advancements in examination techniques or to address
NRC conditions imposed in one of the RGs that have been incorporated
by reference into Sec. 50.55a. The ASME defines ``reaffirmed'' as
an OM Code Case that does not have any change to technical content,
but includes editorial changes.
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[[Page 7823]]
III. Discussion
This proposed rule would incorporate by reference NUREG-2228 and
the latest revisions of the NRC's RGs that list the ASME BPV and OM
Code Cases that the NRC finds to be acceptable, or acceptable with NRC-
specified conditions (``conditionally acceptable''). Regulatory Guide
1.84, Revision 39 (DG-1366) would supersede the incorporation by
reference of Revision 38; RG 1.147, Revision 20 (DG-1367) would
supersede the incorporation by reference of Revision 19; and RG 1.192,
Revision 4 (DG-1368) would supersede the incorporation by reference of
Revision 3.
The ASME Code Cases that are the subject of this proposed rule are
the new and revised Section III and Section XI Code Cases as listed in
Supplements 0 through 7 to the 2015 Edition of the ASME BPV Code,
Supplements 0 through 7 to the 2017 Edition of the ASME BPV Code,
Supplements 0 and 1 to the 2019 Edition of the ASME BPV Code, and the
OM Code Cases listed in the 2020 Edition of the ASME OM Code.
The latest editions and addenda of the ASME BPV and OM Codes that
the NRC has approved for use are referenced in Sec. 50.55a. The ASME
also publishes Code Cases that provide alternatives to existing Code
requirements that the ASME developed and approved. This proposed rule
would incorporate by reference the most recent revisions of RGs 1.84,
1.147, and 1.192, which allow nuclear power plant licensees, and
applicants for combined licenses, standard design certifications,
standard design approvals, and manufacturing licenses under the
regulations that govern license certifications, to use the Code Cases
listed in these RGs as suitable alternatives to the ASME BPV and OM
Codes for the construction, inservice inspections, and inservice
testing of nuclear power plant components. Because the NRC is proposing
to require the use of NUREG-2228, ``Weld Residual Stress Finite Element
Analysis Validation: Part II--Proposed Validation Procedure,'' within a
condition on Code Case N-847, the NRC is also incorporating by
reference NUREG-2228. The ASME publishes the OM Code Cases and lists
the Code Cases in the ASME OM Code edition. In contrast, the ASME
publishes BPV Code Cases in a separate document and at a different time
than the ASME BPV Code Editions. This proposed rule identifies the Code
Cases by the edition of the ASME BPV Code or ASME OM Code under which
they were published by the ASME.
The following general guidance applies to the use of the ASME Code
Cases approved in the latest versions of the RGs that are incorporated
by reference into Sec. 50.55a as part of this proposed rule.
Specifically, the use of the Code Cases listed in the latest versions
of RGs 1.84, 1.147, and 1.192 are acceptable with the specified
conditions when implementing the editions and addenda of the ASME BPV
and OM Codes incorporated by reference in Sec. 50.55a.
The approval of a Code Case in the NRC's RGs constitutes acceptance
of its technical position for applications that are not precluded by
regulatory or other requirements or by the recommendations in these or
other RGs. The applicant or licensee is responsible for ensuring that
use of the Code Case does not conflict with regulatory requirements or
licensee commitments. The Code Cases listed in the RGs are acceptable
for use within the limits specified in the Code Cases. If the RG states
an NRC condition on the use of a Code Case, then the NRC condition
supplements and does not supersede any condition(s) specified in the
Code Case, unless otherwise stated in the NRC condition.
The ASME Code Cases may be revised for many reasons (e.g., to
incorporate operational examination and testing experience and to
update material requirements based on research results). On occasion,
an inaccuracy in an equation is discovered or an examination, as
practiced, is found not to be adequate to detect a newly discovered
degradation mechanism.
Therefore, when an applicant or a licensee initially implements a
Code Case, Sec. 50.55a requires that the applicant or the licensee
implement the most recent version of that Code Case, as listed in the
RGs incorporated by reference. Code Cases superseded by revision are no
longer acceptable for new applications unless otherwise indicated.
Section III of the ASME BPV Code applies to new construction (i.e.,
the edition and addenda to be used in the construction of a plant are
selected based on the date of the construction permit and are not
changed thereafter, except voluntarily by the applicant or the
licensee). Hence, if a Section III Code Case is implemented by an
applicant or a licensee and a later version of the Code Case is
incorporated by reference into Sec. 50.55a and listed in the RG, the
applicant or licensee may use either version of the Code Case (subject,
however, to whatever change requirements apply to its licensing basis
(e.g., Sec. 50.59)) until the next mandatory inservice inspection or
inservice testing update.
A licensee's inservice inspection and inservice testing programs
must be updated every 10 years to the latest edition and addenda of the
ASME BPV Code, Section XI, and the OM Code, respectively, that were
incorporated by reference into Sec. 50.55a and in effect 18 months
prior to the start of the next inspection and testing interval.
Licensees that were using a Code Case prior to the effective date of
its revision may continue to use the previous version for the remainder
of the 120-month inservice inspection or inservice testing interval.
This relieves licensees of the burden of having to update their
inservice inspection or inservice testing program each time a Code Case
is revised by the ASME and approved for use by the NRC. Code Cases
apply to specific editions and addenda, and Code Cases may be revised
if they are no longer accurate or adequate, so licensees choosing to
continue using a Code Case during the subsequent inservice inspection
or inservice testing interval must implement the latest version
incorporated by reference into Sec. 50.55a and listed in the RGs.
The ASME may annul Code Cases that are no longer required, are
determined to be inaccurate or inadequate, or have been incorporated
into the BPV or OM Codes. A Code Case may be revised, for example, to
incorporate user experience. The older or superseded version of the
Code Case cannot be applied by the licensee or applicant for the first
time.
If an applicant or a licensee applied a Code Case before it was
listed as superseded, the applicant or the licensee may continue to use
the Code Case until the applicant or the licensee updates its
construction Code of Record (in the case of an applicant, updates its
application) or until the licensee's 120-month inservice inspection or
inservice testing update interval expires, after which the continued
use of the Code Case is prohibited unless NRC authorization is given
under Sec. 50.55a(z). If a Code Case is incorporated by reference into
Sec. 50.55a and later a revised version is issued by the ASME because
experience has shown that the design analysis, construction method,
examination method, or testing method is inadequate, the NRC will amend
Sec. 50.55a and the relevant RG to remove the approval of the
superseded Code Case. Applicants and licensees should not begin to
implement such superseded Code Cases in advance of the rulemaking.
[[Page 7824]]
A. Code Cases Proposed To Be Approved for Unconditional Use
The Code Cases discussed in Table I are new, revised, or reaffirmed
Code Cases in which the NRC is not proposing any conditions. The table
identifies the draft regulatory guide listing the applicable Code Case
that the NRC proposes to approve for use.
Table I--Acceptable Code Cases
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Code Case No. Published with supplement Title
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Boiler and Pressure Vessel Code Section III
(addressed in DG-1366, Table 1)
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N-249-17.............................. 0 (2019 Edition)........................ Additional Materials for
Subsection NF, Classes 1, 2,
3, and MC Supports Fabricated
without Welding, Section III,
Division 1.
N-539-1............................... 0 (2017 Edition)........................ UNS N08367 in Class 2 and 3
Valves, Section III, Division
1.
N-692-1............................... 6 (2015 Edition)........................ Use of Standard Welding
Procedures, Section III,
Division 1.
N-721-1............................... 5 (2017 Edition)........................ Alternative Rules for Linear
Piping Supports, Section III,
Division 1.
N-801-3............................... 1 (2017 Edition)........................ Rules for Repair of N-Stamped
Class 1, 2, and 3 Components,
Section III, Division 1.
N-822-4............................... 7 (2015 Edition)........................ Application of the ASME
Certification Mark, Section
III, Divisions 1, 2, 3, and
5.
N-855................................. 2 (2015 Edition)........................ SB-148 C95800 Valves for Class
3 Construction, Section III,
Division 1.
N-856................................. 2 (2015 Edition)........................ SA-494 Grade CW-12MW (UNS
N30002) Nickel Alloy Castings
for Construction of NPS 2\1/
2\ and Smaller Flanged Valves
for Class 3 Construction,
Section III, Division 1.
N-859................................. 5 (2015 Edition)........................ Construction of ASME B16.9
Wrought Buttwelding Fittings
and ASME B16.11 Forged
Fittings Made From SB-366 UNS
N04400 Material for Section
III, Class 3 Construction,
Section III, Division 1.
N-863-1............................... 1 (2017 Edition)........................ Post Weld Heat Treatment
(PWHT) of Valve Seal Welds
for P4 and P5A Materials,
Section III, Division 1.
N-866................................. 0 (2017 Edition)........................ Alternative Materials for
Construction of Section III,
Class 2 Vessels, Section III,
Division 1.
N-870-1............................... 4 (2017 Edition)........................ Rules for the Elimination of
External Surface Defects on
Class 1, 2, and 3 Piping,
Pumps, or Valves After
Component Stamping and Prior
to Completion of the N-3 Data
Report, Section III, Division
1.
N-879................................. 1 (2017 Edition)........................ Use of Micro-Alloyed Carbon
Steel Bar in Patented
Mechanical Joints and
Fittings, Classes 1, 2, and
3, Section III, Division 1.
N-884................................. 0 (2019 Edition)........................ Procedure to Determine Strain
Rate for Use with the
Environmental Fatigue Design
Curve Method and the
Environmental Fatigue
Correction Factor, Fen,
Method as Part of an
Environmental Fatigue
Evaluation for Components
Analyzed per the NB-3200
Rules, Section III, Division
1.
N-887................................. 6 (with errata issued in 3/19E)......... Alternatives to the
Requirements of NB-4424.2(a),
Figure NB-4250-2, and Figure
NB-4250-3, Section III,
Division 1.
N-891................................. 0 (2019 Edition)........................ Alternative Requirements to
Appendix XXVI, XXVI-2400,
XXVI-4130, and XXVI-4131 for
Inspection and Repair of
Indentations for Polyethylene
Pipe and Piping Components,
Section III, Division 1.
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Boiler and Pressure Vessel Code Section XI
(addressed in DG-1367, Table 1)
----------------------------------------------------------------------------------------------------------------
N-561-3............................... 0 (2019 Edition)........................ Alternative Requirements for
Wall Thickness Restoration of
Class 2 and High Energy Class
3 Carbon Steel Piping,
Section XI, Division 1.
N-638-10.............................. 1 (2019 Edition)........................ Similar and Dissimilar Metal
Welding Using Ambient
Temperature Machine GTAW
Temper Bead Technique,
Section XI, Division 1.
N-653-2............................... 2 (2015 Edition)........................ Qualification Requirements for
Full Structural Overlaid
Wrought Austenitic Piping
Welds, Section XI, Division
1.
N-702-1............................... 1 (2019 Edition)........................ Alternative Requirements for
Boiling Water Reactor (BWR)
Nozzle Inner Radius and
Nozzle-to-Shell Welds,
Section XI, Division 1.
N-716-2............................... 0 (2017 Edition)........................ Alternative Piping
Classification and
Examination Requirements,
Section XI, Division 1.
N-768................................. 0 (2019 Edition)........................ Alternative Volumetric
Coverage Requirements for
Ultrasonic Examination of
Class 1 and 2 Pressure Vessel
Weld Joints Greater Than 2
in. (50 mm) in Thickness,
Section XI, Division 1.
N-786-3............................... 1 (2017 Edition)........................ Alternative Requirements for
Sleeve Reinforcement of Class
2 and 3 Moderate Energy
Carbon Steel Piping, Section
XI, Division 1.
N-789-3............................... 1 (2017 Edition)........................ Alternative Requirements for
Pad Reinforcement of Class 2
and 3 Moderate Energy Carbon
Steel Piping for Raw Water
Service, Section XI, Division
1.
N-809................................. 2 (2015 Edition)........................ Reference Fatigue Crack Growth
Rate Curves for Austenitic
Stainless Steels in
Pressurized Reactor Water
Environments, Section XI,
Division 1.
N-845-1............................... 6 (2015 Edition)........................ Qualification Requirements for
Bolts and Studs, Section XI,
Division 1.
N-848-1............................... 0 (2017 Edition)........................ Alternative Characterization
Rules for Quasi-Laminar
Flaws, Section XI, Division
1.
N-851................................. 0 (2015 Edition)........................ Alternate Method for
Establishing the Reference
Temperature for Pressure
Retaining Materials, Section
XI, Division 1.
N-858................................. 2 (2017 Edition)........................ Alternative Volumetric
Coverage Requirements for
Ultrasonic Examination of
Class 1 Nozzle-to-Vessel
Welds, Section XI, Division
1.
N-865................................. 2 (2017 Edition)........................ Alternative Requirements for
Pad Reinforcement of Class 2
and 3 Atmospheric Storage
Tanks, Section XI, Division
1.
N-867................................. 0 (2017 Edition)........................ Clarification of NDE Practical
Examination Requirements,
Section XI, Division 1.
N-873................................. 1 (2017 Edition)........................ Examination Requirements for
the Core Makeup Tanks,
Section XI, Division 1.
[[Page 7825]]
N-874................................. 7 (2017 Edition)........................ Temporary Acceptance of
Leakage Through Brazed Joints
of Class 3 Copper, Copper-
Nickel, and Nickel-Copper
Moderate Energy Piping,
Section XI, Division 1.
N-877................................. 2 (2017 Edition)........................ Alternative Characterization
Rules for Multiple Subsurface
Radially Oriented Planar
Flaws, Section XI, Division
1.
N-882................................. 6 (2017 Edition)........................ Alternative Requirements for
Attaching Nonstructural
Electrical Connections to
Class 2 and 3 Components,
Section XI, Division 1.
N-885................................. 0 (2019 Edition)........................ Alternative Requirements for
Table IWB-2500-1, Examination
Category B-N-1, Interior of
Reactor Vessel, Category B-N-
2, Welded Core Support
Structures and Interior
Attachments to Reactor
Vessels, Category B-N-3,
Removable Core Support
Structures, Section XI,
Division 1.
N-892................................. 0 (2019 Edition)........................ Alternative Requirement for
Form OAR-1, Owner's Activity
Report, Completion Time,
Section XI, Division 1.
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Operation and Maintenance Code
(addressed in DG-1368, Table 1)
----------------------------------------------------------------------------------------------------------------
OMN-13, Revision 3.................... 2020 Edition............................ Performance-Based Requirements
for Extending Snubber
Inservice Visual Examination
Interval at LWR Power Plants.
OMN-15, Revision 3.................... 2020 Edition............................ Performance-Based Requirements
for Extending the Snubber
Operational Readiness Testing
Interval at LWR Power Plants.
OMN-17, Revision 1.................... 2020 Edition............................ Alternative Requirements for
Testing ASME Class 1 Pressure
Relief/Safety Valves.
OMN-22................................ 2020 Edition............................ Smooth Running Pumps.
OMN-23................................ 2020 Edition............................ Alternative Requirements for
Testing Pressure Isolation
Valves.
OMN-24................................ 2020 Edition............................ Alternative Requirements for
Testing ASME Class 2 and 3
Pressure Relief Valves (For
Relief Valves in a Group of
One).
OMN-25................................ 2020 Edition............................ Alternative Requirements for
Testing Appendix I Pressure
Relief Valves.
OMN-26................................ 2020 Edition............................ Alternate Risk-Informed and
Margin Based Rules for
Inservice Testing of Motor
Operated Valves.
OMN-27................................ 2020 Edition............................ Alternative Requirements for
Testing Category A Valves
(Non-PIV/CIV).
----------------------------------------------------------------------------------------------------------------
B. Code Cases Approved for Use With Conditions
The NRC has determined that certain Code Cases, as issued by the
ASME, are generally acceptable for use, but that the alternative
requirements specified in those Code Cases must be supplemented in
order to provide an acceptable level of quality and safety.
Accordingly, the NRC proposes to impose conditions on the use of these
Code Cases to modify, limit or clarify their requirements. The
conditions would specify, for each applicable Code Case, the additional
activities that must be performed, the limits on the activities
specified in the Code Case, and/or the supplemental information needed
to provide clarity. These ASME Code Cases, listed in Table II, are
included in Table 2 of DG-1366 (RG 1.84), DG-1367 (RG 1.147), and DG-
1368 (RG 1.192). This section provides the NRC's evaluation of the Code
Cases and the reasons for the NRC's conditions. Notations indicate the
conditions duplicated from previous versions of the RG.
The NRC requests public comment on these Code Cases and the
proposed conditions. It should also be noted that this section only
addresses those Code Cases for which the NRC proposes to impose
condition(s), which are listed in the RG for the first time.
Table II--Conditionally Acceptable Code Cases
----------------------------------------------------------------------------------------------------------------
Code Case No. Published with supplement Title
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section III
(addressed in DG-1366, Table 2)
----------------------------------------------------------------------------------------------------------------
N-71-20............................... 6 (2015 Edition)........................ Additional Materials for
Subsection NF, Class 1, 2, 3,
and MC Supports Fabricated by
Welding, Section III,
Division 1.
N-155-3............................... 5 (2015 Edition)........................ Fiberglass Reinforced
Thermosetting Resin Pipe,
Section III, Division 1.
N-755-4............................... 1 (2017 Edition)........................ Use of Polyethylene (PE) Class
3 Plastic Pipe, Section III,
Division 1.
N-779................................. 9 (2007 Edition)........................ Alternative Rules for
Simplified Elastic-Plastic
Analysis Class 1, Section
III, Division 1.
N-852................................. 0 (2015 Edition)........................ Application of the ASME NPT
Stamp, Section III, Divisions
1, 2, 3, and 5.
N-883................................. 5 (2017 Edition)........................ Construction of Items Prior to
the Establishment of a
Section III, Division 1
Owner, Section III, Division
1.
N-886................................. 6 (2017 Edition)........................ Use of Polyethylene Pipe for
Class 3, Section III,
Division 1.
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section XI
(addressed in DG-1367, Table 2)
----------------------------------------------------------------------------------------------------------------
N-513-5............................... 6 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of Flaws
in Moderate Energy Class 2 or
3 Piping and Gate Valves,
Section XI, Division 1.
N-516-5............................... 6 (2015 Edition)........................ Underwater Welding, Section
XI, Division 1.
[[Page 7826]]
N-705-1............................... 2 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of
Degradation in Moderate
Energy Class 2 or 3 Vessels
and Tanks, Section XI,
Division 1.
N-766-3............................... 2 (2017 Edition)........................ Nickel Alloy Reactor Coolant
Inlay and Onlay for
Mitigation of PWR Full
Penetration Circumferential
Nickel Alloy Dissimilar Metal
Welds in Class 1 Items,
Section XI, Division 1.
N-831-1............................... 7 (2017 Edition)........................ Ultrasonic Examination in Lieu
of Radiography for Welds in
Ferritic or Austenitic Pipe,
Section XI, Division 1.
N-847................................. 0 (2017 Edition)........................ Partial Excavation and
Deposition of Weld Metal for
Mitigation of Class 1 Items,
Section XI, Division 1.
N-864................................. 2 (2017 Edition)........................ Reactor Vessel Threads in
Flange Examinations, Section
XI, Division 1.
N-869................................. 6 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of Flaws
in Class 2 or 3 Piping,
Section XI, Division 1.
N-876................................. 2 (2017 Edition)........................ Austenitic Stainless Steel
Cladding and Nickel Base
Cladding Using Ambient
Temperature Automatic or
Machine Dry Underwater Laser
Beam Welding (ULBW) Temper
Bead Technique, Section XI,
Division 1.
N-878................................. 1 (2017 Edition)........................ Alternative to QA Program
Requirements of IWA-4142,
Section XI, Division 1.
N-880................................. 2 (2017 Edition)........................ Alternative to Procurement
Requirements of IWA-4143 for
Small Nonstandard Welded
Fittings, Section XI,
Division 1.
N-889................................. 7 (2017 Edition)........................ Reference Stress Corrosion
Crack Growth Rate Curves for
Irradiated Austenitic
Stainless Steel in Light-
Water Reactor Environments,
Section XI, Division 1.
N-890................................. 0 (2019 Edition)........................ Materials Exempted From G-
2110(b) Requirement, Section
XI, Division 1.
----------------------------------------------------------------------------------------------------------------
Operation and Maintenance Code
(addressed in DG-1368, Table 2)
----------------------------------------------------------------------------------------------------------------
OMN-1, Revision 2..................... 2020 Edition............................ Alternative Rules for
Preservice and Inservice
Testing of Active Electric
Motor-Operated Valve
Assemblies in Light-Water
Reactor Power Plants.
OMN-3................................. 2020 Edition............................ Requirements for Safety
Significance Categorization
of Components Using Risk
Insights for Inservice
Testing of LWR Power Plants.
OMN-4................................. 2020 Edition............................ Requirements for Risk Insights
for Inservice Testing of
Check Valves at LWR Power
Plants.
OMN-9................................. 2020 Edition............................ Use of a Pump Curve for
Testing.
OMN-12................................ 2020 Edition............................ Alternative Requirements for
Inservice Testing Using Risk
Insights for Pneumatically
and Hydraulically Operated
Valve Assemblies in Light-
Water Reactor Power Plants
(OM-Code 1998, Subsection
ISTC).
OMN-18................................ 2020 Edition............................ Alternate Testing Requirements
for Pumps Tested Quarterly
Within 20% of
Design Flow.
OMN-19................................ 2020 Edition............................ Alternative Upper Limit for
the Comprehensive Pump Test.
OMN-20................................ 2020 Edition............................ Inservice Test Frequency.
----------------------------------------------------------------------------------------------------------------
1. ASME BPV Code, Section III Code Cases (DG-1366/RG 1.84)
Code Case N-71-20 [Supplement 6, 2015 Edition]
Type: Revised.
Title: Additional Materials for Subsection NF, Class 1, 2, 3, and
MC Supports Fabricated by Welding, Section III, Division 1.
The proposed conditions on Code Case N-71-20 are the same as the
conditions on N-71-19 that were approved by the NRC in Revision 38 of
RG 1.84. When the ASME revised N-71, the Code Case was not modified in
a way that would make it possible for the NRC to remove the conditions.
Therefore, the conditions would be retained in Revision 39 of RG 1.84.
Code Case N-155-3 [Supplement 5, 2015 Edition]
Type: Revised.
Title: Fiberglass Reinforced Thermosetting Resin Pipe, Section III,
Division 1.
The proposed conditions on Code Case N-155-3 are the same as the
conditions on N-155-2 that were approved by the NRC in Revision 38 of
RG 1.84. When the ASME revised N-155-2, the Code Case was not modified
in a way that would make it possible for the NRC to remove the
conditions. Therefore, the conditions would be retained in Revision 39
of RG 1.84.
Code Case N-755-4 [Supplement 1, 2017 Edition]
Type: Revised.
Title: Use of Polyethylene (PE) Class 3 Plastic Pipe, Section III,
Division 1.
This Code Case is applicable only to butt fusion joints and the
content was incorporated into Mandatory Appendix XXVI in 2015 Edition
of Section III of the ASME Code. The relevant provisions of Code Case
N-755-4 are the same as those in Mandatory Appendix XXVI. Therefore,
the NRC is applying the same conditions to Code Case N-755-4. The NRC
has determined that these conditions are necessary to ensure structural
integrity of the polyethylene piping and fusion joints when the
polyethylene piping is used in Class 3 safety-related applications.
Code Case N-779 [Supplement 9, 2007 Edition]
Type: New.
Title: Alternative Rules for Simplified Elastic-Plastic Analysis
Class 1, Section III, Division 1.
The NRC finds the Code Case satisfactory and technically acceptable
for use only with code editions Summer 1979 and later. This Code Case,
as written, is not acceptable for use with editions of Section III
earlier than the Summer 1979 edition, which included the term Delta T1
in NB-3600 Equation 10, because the Code Case is based on equations
used in the Summer 1979 edition and later editions of the Code.
Code Case N-852 [Supplement 0, 2015 Edition]
Type: New.
Title: Application of the ASME NPT Stamp, Section III, Divisions 1,
2, 3, and 5.
[[Page 7827]]
The NRC approved this Code Case with conditions in a Sec. 50.55a
rulemaking issued in 2017 (82 FR 32934, Sept. 18, 2017), and the
supplement was not modified in a way that would make it possible for
the NRC to remove the conditions. Therefore, the NRC is including a
condition that this Code Case can only be used for the service life of
a component that had the horizontally arranged NPT Code Symbol Stamp
applied during the time period from January 1, 2005, through December
31, 2015.
Code Case N-883 [Supplement 5, 2017 Edition]
Type: New.
Title: Construction of Items Prior to the Establishment of a
Section III, Division 1 Owner, Section III, Division 1.
This Code Case allows certificate holders to construct all items
prior to the establishment of an Owner. Code Case N-883 was developed
to address international stakeholders and identify the ASME as a global
standard development organization. The NRC's main concern is that
without the designation of an Owner, the NRC would not be able to
provide regulatory oversight of the ASME certificate holder
manufacturing the items, which is not consistent with appendix B to 10
CFR part 50 and the requirements in Sec. 50.55(a) for a basic
component. During discussions with the ASME staff on this Code Case, it
was determined that the NRC would condition this Code Case based on
regulatory oversight, as would other regulatory bodies depending on
each countries' specific regulations. This is evident as this Code Case
specifies that the ``the items have been constructed by [ASME]
Certificate Holders who are specifically authorized by the Regulatory
Authority having jurisdiction over the Owner's facility to construct
items using this Case.'' The proposed condition, ``This Code Case may
be used for the construction of items by a holder of a construction
permit, operating license, or combined license under 10 CFR part 50 or
part 52,'' provides this specific regulatory authorization thereby
ensuring the appropriate regulatory oversight.
Code Case N-886 [Supplement 6, 2017 Edition]
Type: New.
Title: Use of Polyethylene Pipe for Class 3, Section III, Division
1.
This Code Case is applicable for the use of polyethylene pipe in
Section III, Class 3, Division 1 above ground applications. This Code
Case refers to Mandatory Appendix XXVI of Section III of the ASME Code.
The 2015 Edition of Appendix XXVI contains requirements for butt fusion
joints for buried piping. The 2017 Edition of Appendix XXVI contains
requirements for butt fusion and electrofusion joints for buried
piping. Therefore, all the conditions as noted in Section III of the
2015-2017 Code Edition rule related to buried piping Mandatory Appendix
XXVI apply to this Code Case. The same conditions as buried piping also
apply to above ground application. Two additional conditions are needed
for above ground applications, one on fire protection and one on carbon
black distribution to protect from windows and delamination. A
condition on fire protection is needed because polyethylene material is
combustible and above ground uses are more susceptible to fire hazards.
In addition, a condition requiring homogeneous carbon black
distributiuon is needed because experiments have shown that
inhomogeneous carbon black distribution can lead to windows and
delamination.
2. ASME BPV Code, Section XI Code Cases (DG-1367/RG 1.147)
Code Case N-513-5 [Supplement 6, 2017 Edition]
Type: Revised.
Title: Evaluation Criteria for Temporary Acceptance of Flaws in
Moderate Energy Class 2 or 3 Piping and Gate Valves, Section XI,
Division 1.
Code Case N-513-5 contains provisions to permit temporary
acceptance of flaws, in moderate energy Class 2 or 3 piping, including
elbows, pipe bends, reducers, expanders, branch tees, and gate valves
without performing a repair/replacement activity for a limited period.
The Code Case contains provisions regarding the scope, flaw
characterization, periodic leakage monitoring, flaw evaluation, and
augmented examinations. The NRC finds that the provisions of N-513-5
are acceptable except for the augmented examination provisions in
Section 5 of the Code Case.
When a licensee applies N-513-5 to disposition a through-wall leak
or wall thinning in a piping system, Section 5 of the Code Case
requires augmented examinations for flaws and significant flaws. The
augmented examination requirements in N-513-5 are the same as in Code
Case, N-513-3.
In 2018, the NRC found an instance where a licensee misinterpreted
the provisions in Section 5 of N-513-3 and did not perform the required
augmented examinations to disposition a through-wall leak in a service
water system pipe. Other licensees have similarly misinterpreted the
augmented examination provisions in Section 5 of N-513-3. The NRC found
that the issue stems from the definition of the terms ``flaw'' and
``significant flaw'' in Sections 5(b) and 5(c) of N-513-3,
respectively. The NRC, therefore, proposes two conditions to define
``flaw'' and ``significant flaw'' as those terms are used in Section 5
of N-513-5. Licensees would be required to apply these definitions to
Section 5 when using the Code Case.
The first proposed condition defines a ``flaw'' as a non-through-
wall planar or nonplanar flaw with a wall thickness less than 87.5
percent of the nominal wall thickness of the pipe or the design minimum
wall thickness. The NRC notes that the pipe wall thickness at the time
of the plant construction may deviate from the nominal pipe wall
thickness slightly as part of manufacturing process. The generally
accepted deviation is 12.5 percent of the nominal pipe wall thickness
or the design minimum wall thickness.
The second proposed condition defines ``significant flaw'' as any
pipe location that does not satisfy the provisions of Section 3 of N-
513-5 or if any detected flaw that has a depth greater than 75 percent
of the pipe wall thickness. The NRC staff notes that the criterion of
the 75 percent wall thickness criterion originates from the provisions
of IWC/IWD-3643 of the ASME Code, Section XI, which prohibits a flaw
that exceeds 75 percent of the pipe wall thickness to remain in
service. Under Section 5 of N-513-5, a planar flaw that exceeds 75
percent of the pipe wall thickness may remain in service; however, the
licensee must perform an augmented examination.
Code Case N-516-5 [Supplement 6, 2015 Edition]
Type: Revised.
Title: Underwater Welding, Section XI, Division 1.
In the rulemaking for the 2009 Addenda through 2013 Editions of the
ASME Code (82 FR 32934, Sept. 18, 2017), the NRC-specified conditions
that should be applied to Section XI, Article IWA-4660 when performing
underwater welding on irradiated materials. These conditions provide
guidance on what level of neutron irradiation and/or helium content
would require review and approval by the NRC because of the impact of
neutron fluence on weldability. These conditions provide separate
criteria for three generic classes of material: Ferritic material,
austenitic material other than P-No. 8 (e.g., nickel-based alloys) and
austenitic P-No. 8
[[Page 7828]]
material (e.g., stainless steel alloys). These conditions are currently
located in Sec. 50.55a(b)(2)(xii)(A) and (B). The conditions located
in Sec. 50.55a(b)(2)(xii)(A) and (B) are identical to the conditions
that were imposed on Code Case N-516-4 that were approved by the NRC in
Revision 19 of RG 1.147. When the ASME revised N-516, the Code Case was
not modified in a way that would make it possible for the NRC to remove
the conditions. Therefore, the conditions will be retained in Revision
20 of RG 1.147 by stating the provisions of Sec. 50.55a(b)(2)(xii)(A)
and (B) must be met when applying this Code Case.
Code Case N-705-1 [Supplement 2, 2017 Edition]
Type: Revised.
Title: Evaluation Criteria for Temporary Acceptance of Degradation
in Moderate Energy Class 2 or 3 Vessels and Tanks, Section XI, Division
1.
The proposed condition on Code Case N-705-1 is identical to the
condition on N-705 that was approved by the NRC in Revision 19 of RG
1.147. When the ASME revised N-705, the Code Case was not modified in a
way that would make it possible for the NRC to remove the condition.
Therefore, the condition would be retained in Revision 20 of RG 1.147.
Code Case N-766-3 [Supplement 2, 2017 Edition]
Type: Revised.
Title: Nickel Alloy Reactor Coolant Inlay and Onlay for Mitigation
of PWR Full Penetration Circumferential Nickel Alloy Dissimilar Metal
Welds in Class 1 Items, Section XI, Division 1.
The proposed conditions on Code Case N-766-3 are identical to the
conditions on N-766-1 that were approved by the NRC in Revision 19 of
RG 1.147. When the ASME revised N-766, the Code Case was not modified
in a way that would make it possible for the NRC to remove the
conditions. Therefore, the conditions would be retained in Revision 20
of RG 1.147.
Code Case N-831-1 [Supplement 7, 2017 Edition]
Type: Revised.
Title: Ultrasonic Examination in Lieu of Radiography for Welds in
Ferritic or Austenitic Pipe, Section XI, Division 1.
The proposed condition on Code Case N-831-1 is identical to the
condition on N-831 that was approved by the NRC in Revision 19 of RG
1.147. When ASME revised N-831, the Code Case was not modified in a way
that would make it possible for the NRC to remove the condition.
Therefore, the condition would be retained in Revision 20 of RG 1.147.
Code Case N-847 [Supplement 0, 2017 Edition]
Type: New.
Title: Partial Excavation and Deposition of Weld Metal for
Mitigation of Class 1 Items, Section XI, Division 1.
ASME Code Case N-847 provides guidelines for a repair/mitigation
process for welds. The process, excavation and weld repair (EWR),
removes susceptible material from the outside diameter of the pipe, and
replaces it with more resistant weld material. This technique allows
for the potential of two mitigation methods, the use of more crack
resistant material and the potential for compressive stresses on the
inside surface of the repaired/mitigated weld to arrest or prevent
cracking. Finally, the excavation can be done 360-degrees around the
weld or only for a partial arc of the weld.
The Code Case would allow for application of this process to both
BWR and PWR designs. However, the EWR process, as defined in this code
case, has certain challenges addressing the cracking mechanisms in
these operating enviornments and materials. In addition the regulatory
requirements or guidelines related to the Code Case vary depending on
the design of the reactor. For PWR designs, the inservice inspection
rules are provided by Sec. 50.55a(g)(6)(ii)(F), which mandates the
implementation of a version of ASME Code Case N-770. For BWR designs,
the inservice inspection guidelines are provided by Generic Letter 88-
01, ``NRC Position on Intergranular Stress Corrosion Cracking (IGSCC)
in BWR Austenitic Stainless Steel Piping'' or BWRVIP-75-A, ``BWR Vessel
and Internals Project Technical Basis for Revisions to Generic Letter
88-01 Inspection Schedules.'' Therefore, the NRC is proposing six
conditions to ensure the inservice inspection frequency guidelines of
the code case are inline with the previous requirements and guidance,
which are based on the effectiveness of the overall design of the
repair/mitigation to address the various cracking mechanisms of these
operating reactor designs.
The first proposed condition is a continuation of the condition of
Sec. 50.55a(g)(6)(ii)(F)(16) which requires that a partial arc EWR, as
described in Inspection Item O of ASME Code Case N-770-5, cannot be
used without NRC review and approval for PWR designs. The NRC notes
that the issues addressed in the final rule incorporating by reference
the 2015 and 2017 Editions of the ASME BPV Code and the 2015 and 2017
Editions of the ASME OM Code remain applicable, and futher apply to BWR
design application of a partial arc EWR. These concerns are for the
effectiveness of the repair through a weld residual stress calculation
and flaw growth analysis to confirm design of the mitigation for the
required inspection interval, non-destructive examination uncertainty
analysis of the as-found flaw remaining in the reactor coolant pressure
boundary, and the potential for further crack initiation or growth.
Therefore, the NRC requires, through the first condition, that approval
of the use of this Code Case is only for the application of the 360-
degee EWR.
The second proposed condition is related to Figure 1A and Figure 1B
of the Code Case. The NRC has experience with relief request
submittals, where the details associated with the configuration of the
prep area, where the defect is being removed, have shown sharp bottom
edges and steep walls. This geometry can result in welding issues,
which could result in unfused material, leading to stress risers, which
may promote cracking. Therefore, the NRC requires, through the second
condition, that the intersection points at the interface between EWR
metal and existing base metal must be rounded to minimize stress
concentration.
The third proposed condition is related to Section 2(d)(2) of the
Code Case which discusses the flaw evaluations required for the design
considerations of the EWR. In recent testing conducted for the NRC
measurable stress corrosion cracking (SCC) growth was detected past the
interface between the SCC-susceptible and less susceptible material. It
was demonstrated that the crack can branch and propagate in a direction
normal to the original direction along a SCC-susceptible path. In the
Alloy 52M deposited onto Alloy 182 specimens tested, this occurred in
the diluted region of the Alloy 52M material as well as the weld metal.
Therefore, the NRC requires, through the third condition, that flaw
analysis include the potential for crack growth through the dilution
zone. As NRC-approved crack growth rates are not available for all
material types (e.g., Alloy 690 weld material), the alternative
requirements for development of crack growth rates should be consistent
with ASME Section XI Appendix C, ``Flaw Growth Rate Due to Stress
Corrosion Cracking,'' C-3220(a).
The fourth proposed condition is related to Section 2 of the Code
Case. The NRC is requiring the use of
[[Page 7829]]
NUREG-2228, ``Weld Residual Stress Finite Element Analysis Validation:
Part II--Proposed Validation Procedure,'' because it provides a proven
method for validating the weld residual stress analysis methodology.
Because the NRC requires the use of NUREG-2228 within this condition on
the requirements in the Code Case, the NRC is incorporating by
reference NUREG-2228 into Sec. 50.55a(a)(3)(iv).
The fifth condition is related to the longer term volumetric
inspection frequencies of Table 1, including notes (1), (3), and (4).
These notes provide the BWR design inspection frequency of various EWR
types based on Generic Letter 88-01 (1988) as supplemented by Generic
Letter 88-01, Supplement 1 (1992), ``NRC Position on Intergranular
Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel
Piping'' or BWRVIP-75-A, ``BWR Vessel and Internals Project Technical
Basis for Revisions to Generic Letter 88-01 Inspection Schedules.'' The
NRC has concluded that the inspection requirements for EWRs for BWRs
need to be augmented.
The first volumetric examination following application of BWR EWR-
2A, EWR-1B, and EWR-2B welds is performed to verify effectiveness of
the repair/mitigation before the new weld can be placed in a longer
term volumetric inspection frequency. The Code Case allows licensees
the option of performing this examination during the first or second
refueling outage after installation. However, based on the lower
operating temperatures of a BWR (approximately 546 degree F to 558
degree F), and hence the potential slow crack growth rate of the
remaining flaw left in service, the NRC has concluded that the
examination should occur during the second refueling outage after the
EWR application to provide adequate time for any potential measurable
flaw growth to occur or in the case of an EWR-2A, for crack initiation
and growth to occur.
The long term volumetric inspections for BWRs require modification
because: (a) For EWR-1A EWRs, the augmented inspection requirements are
consistent with the conditions of the inspection frequencies of Code
Case N-770-5. These inspection frequency requirements were previously
developed by the NRC based on the capabilities of the EWR process to
address stress corrosion cracking while providing significant credit
for the use of hydrogen water chemistry/noble metal chemical addition
controls; and (b) for EWR-1B EWRs, due to the design which would allow
a crack to be left in service, should not be allowed to go uninspected
for the remainder of plant life. Therefore, the NRC requires the long
term volumetric inspection of these welds at each 10-year inservice
inspection interval. The NRC notes that this condition is consistent
with the NRC condition established in Sec. 50.55a for Inspection Item
N-1 EWRs (EWR that meets stress criteria; however, a crack is present).
The sixth condition is related to Table 1, Note (1), and the option
to use an unspecified alternative to determine examination frequencies
and scope expansion criteria. Note (1) specifies the use of NRC Generic
Letter 88-01 and includes BWRVIP-75-A as an example of an alternative.
The NRC has concluded that NRC Generic Letter 88-01, (1988) as
supplemented by Generic Letter 88-01, Supplement 1 (1992), or BWRVIP-
75-A, represent sufficient requirements, subject to the fifth condition
above, to determine examination frequencies and scope expansion
criteria. However, Note (1) would allow the use of other, unknown
alternatives and does not provide criteria to ensure alternatives are
adequate for this purpose. Therefore, to ensure that licensees use an
adequate standard to determine examination frequencies and scope
expansion criteria, the sixth condition requires that licensees must
not use an alternative other than those specified in Note (1).
Code Case N-864 [Supplement 2, 2017 Edition]
Type: New.
Title: Reactor Vessel Threads in Flange Examinations, Section XI,
Division 1.
Code Case N-864 proposes to eliminate the required ASME Code,
Section XI examination for the reactor vessel threads-in-flange for all
inservice inspection intervals. The NRC has previously granted
alternatives under Sec. 50.55a(z) that eliminate the reactor pressure
vessel threads-in-flange examinations (ASME Section XI, Examination
Category B-G-1, Item No. B6.40) for up to two inservice inspection
intervals through the NRC's alternative request process. For
alternatives that requested elimination of the examination for a second
consecutive ten-year inservice inspection interval, the NRC has been
requesting additional information on activities performed to ensure
that the condition of the reactor pressure vessel threads-in-flange
receives some level of monitoring. These activities typically have been
care and maintenance of the reactor vessel threads-in-flange (and
studs) whenever the closure head is removed. The NRC has limited
approval of such requests to two subsequent inservice inspection
intervals because the NRC has determined that complete elimination of
the examinations does not provide adequate protection against long-term
degradation of the threads-in-flange. The NRC is proposing conditions
on the use of Code Case N-864 that are consistent with the limits the
NRC has placed on similar alternatives requests.
The first proposed condition in Code Case N-864 requires that the
reactor pressure vessel threads-in-flange examinations (ASME Section
XI, Examination Category B-G-1, Item No. B6.40) must be performed in at
least every third 10-year ISI interval. The first proposed condition
also limits the application of Code Case N-864 at facilities that have
been authorized under 10 CFR 50.55a(z) to use alternatives that
eliminate reactor pressure vessel threads-in-flange examinations to
ensure that the required examination is performed at least every third
10-year inservice inspection interval.
The second proposed condition in Code Case N-864 ensures that
sufficient monitoring and maintenance activities are performed when the
Code Case is applied.
Code Case N-869 [Supplement 6, 2017 Edition]
Type: New.
Title: Evaluation Criteria for Temporary Acceptance of Flaws in
Class 2 or 3 Piping, Section XI, Division 1.
Code Case N-869 contains provisions for temporary acceptance of
flaws, including through-wall flaws in Class 2 or 3 piping including
elbows, pipe bends, reducers, and branch tees, whose maximum operating
pressure is greater than 275 psig, and does not exceed 600 psig,
without performing a repair/replacement activity. The Code Case
contains provisions regarding the scope, flaw characterization,
periodic leakage monitoring, flaw evaluation, and augmented
examinations. The NRC finds that the Code Case provides reasonable
assurance that structural integrity of degraded piping will be
maintained until the next scheduled refueling outage. However, the NRC
finds that the augmented examination provisions in Section 5 of the
Code Case are inadequate and need additional requirements.
When a licensee applies N-869 to disposition a through-wall leak or
wall thinning in a piping system, Section 5 of the Code Case requires
augmented examinations for flaws and significant flaws. The augmented
examination
[[Page 7830]]
requirements in N-869 are the same as in Code Case N-513-3.
In 2018, the NRC found an instance where a licensee misinterpreted
the provisions in Section 5 of N-513-3 and did not perform the required
augmented examinations to disposition a through-wall leak in a service
water system pipe. Other licensees have similarly misinterpreted the
augmented examination provisions in Section 5 of N-513-3. The NRC found
that the issue stems from the definition of the terms ``flaw'' and
``significant flaw'' in Sections 5(b) and 5(c) of N-513-3,
respectively. The NRC, therefore, proposes two conditions to define
``flaw'' and ``significant flaw'' as those terms are used in Section 5
of N-869. Licensees would be required to apply these definitions to
Section 5 when using the Code Case.
The first proposed condition defines a ``flaw'' as a non-through-
wall planar or nonplanar flaw with a wall thickness less than 87.5
percent of the nominal wall thickness of the pipe or the design minimum
wall thickness. The NRC notes that the pipe wall thickness at the time
of the plant construction may deviate from the nominal pipe wall
thickness slightly as part of manufacturing process. The generally
accepted deviation is 12.5 percent of the nominal pipe wall thickness
or the design minimum wall thickness.
The second proposed condition defines ``significant flaw'' as any
pipe location that does not satisfy the provisions of Section 3 of N-
869 or if any detected flaw that has a depth greater than 75 percent of
the pipe wall thickness. The NRC staff notes that the criterion of the
75 percent wall thickness criterion originates from the provisions of
IWC/IWD-3643 of the ASME Code, Section XI, which prohibit a flaw that
exceeds 75 percent of the pipe wall thickness to remain in service.
Under Section 5 of N-869, a planar flaw that exceeds 75 percent of the
pipe wall thickness may remain in service; however, the licensee needs
to perform an augmented examination.
Code Case N-876 [Supplement 2, 2017 Edition]
Type: New.
Title: Austenitic Stainless Steel Cladding and Nickel Base Cladding
Using Ambient Temperature Automatic or Machine Dry Underwater Laser
Beam Welding (ULBW) Temper Bead Technique, Section XI, Division 1.
Some irradiated stainless steel reactor vessel internal components
are susceptible to experiencing irradiation assisted stress corrosion
cracking. Code Case N-876 provides guidelines for repair welding the
irradiated stainless steel components inside the reactor vessel. Code
Case N-876 provides an alternative to the cladding temper bead repair
rules of Section XI, IWA-4400, which requires preheat and postweld heat
treatment. This alternative establishes new rules governing ambient
temperature temper bead cladding repairs using the ULBW process.
The NRC is proposing two conditions on this Code Case. The first
proposed condition that must be applied when performing ULBW on
irradiated materials provides guidance on what level of neutron
irradiation and/or helium content would require review and approval by
the NRC because of the impact of neutron fluence on weldability. The
second proposed condition limits the depth of the cladding repair due
to concerns with the fracture toughness of the base metal.
The technical basis for imposing conditions on the welding of
irradiated materials are that neutrons can generate helium atoms within
the metal lattice through transmutation of various isotopes of boron
and/or nickel. At high temperatures, such as occurs during welding,
these helium atoms rapidly diffuse though the metal lattice, coalescing
and forming helium bubbles at the grain boundaries. In sufficient
concentration, these helium bubbles can cause grain boundary cracking
that occurs in the fusion zones and heat affected zones during the
heat-up/cooldown cycle.
The first proposed condition applies conditions already applicable
to Code Case N-516-5 ``Underwater Welding Section XI, Division 1,''
that the provisions of Sec. 50.55a(b)(2)(xii)(A) and (B) must be met.
This regulation provides limits on specific levels of neutron
irradiation and/or helium content, above which welding is prohibited
without prior NRC review and approval. The NRC is proposing to apply
the same condition to uses of Code Case N-876.
The second proposed condition is necessary because the Code Case
does not require impact testing of the base metal heat affected zone
(HAZ) to verify adequate fracture toughness. The Code Case allows the
depth of the repair cavity into the ferritic base metal to be up to \1/
4\''. This would allow welding directly to the base metal, thus it will
affect the fracture toughness of the base metal in the HAZ. Therefore,
the NRC is proposing a condition restricting the use of the Code Case
to repairs where at least \1/8\'' of cladding remains. The basis for
the \1/8\'' limit is that this amount of austenitic material between
the ferritic base metal and the first weld layer has generally been
considered to sufficiently limit the heat input to the base metal such
that deleterious effects on the fracture toughness will not occur;
therefore, impact testing of the base metal is not necessary. The NRC
notes that Code Case N-803, which is approved without conditions,
allows repair of ferritic base material using nonferritic weld filler
material based on welding procedure qualifications performed using
tensile tests, side bends, and impact tests, and could be used to
perform a cladding repair in which excavation into the base metal is
required.
Code Case N-878 [Supplement 1, 2017 Edition]
Type: New.
Title: Alternative to QA Program Requirements of IWA-4142, Section
XI, Division 1.
Code Case N-878 provides alternatives to the quality assurance
requirements in IWA-4142 for procurement of Class 1, 2, or 3 non-welded
fittings. This Code Case addresses the testing and certification of
material used in the manufacture of non-welded fittings, but does not
address how the licensee must ensure that the procured non-welded
fittings meet the design and testing requirements of the ASME Code,
Section III, NB/NC/ND-3671.7 for Class 1, 2, or 3 applications.
Verification that the Section III requirements for the design and
testing of these non-welded fittings have been met prior to use is
essential in ensuring the structural integrity of these Class 1, 2 and
3 systems is maintained. Therefore, the NRC is proposing conditions for
the licensee to verify the design and testing activities associated
with qualification of non-welded fittings required by Section III, NB/
NC/ND-3671.7 that are performed by the fabricator.
Code Case N-880 [Supplement 2, 2017 Edition]
Type: New.
Title: Alternative to Procurement Requirements of IWA-4143 for
Small Nonstandard Welded Fittings, Section XI, Division 1.
Code Case N-880 provides alternatives to the material procurement
requirements of IWA-4142 and IWA-4143 for small nonstandard welded
fittings. This Code Case does not address how the licensee must ensure
the procured welded fittings meet the design and testing requirements
of the ASME Code, Section III, NB/NC/ND-3671.7 for Class 1, 2, or 3
applications. Verification that the Section III requirements for the
design and testing
[[Page 7831]]
of these welded fittings have been met prior to use is essential in
ensuring the structural integrity of these Class 1, 2 and 3 systems is
maintained. Therefore, the NRC is proposing conditions requiring the
licensee to verify the design and testing activities associated with
qualification of welded fittings required by Section III, NB/NC/ND-
3671.7 that are performed by the fabricator.
Code Case N-889 [Supplement 7, 2017 Edition]
Type: New.
Title: Reference Stress Corrosion Crack Growth Rate Curves for
Irradiated Austenitic Stainless Steel in Light-Water Reactor
Environments, Section XI, Division 1.
Code Case N-889 provides a new crack growth rate (CGR) law for
irradiation-assisted stress corrosion cracking. The Code Case is
applicable to wrought austenitic stainless steels and associated weld
metals, as well as cast austenitic stainless steels. The proposed CGR
law requires the user to first calculate irradiated yield stress from
the dose to the material. There are two yield stress models: One for
Molybdenum bearing stainless steels and one for stainless steels
without Molybdenum. Once irradiated yield stress has been determined,
the user calculates the CGR as a function of applied crack driving
force and temperature.
The staff identified three concerns with the technical basis of
this Code Case. The first concern relates to the limited CGR data at
dose levels greater than 20 displacements per atom (dpa). The proposed
CGR law indicates that the irradiated yield stress (and, consequently,
the CGR) increases with fluence up to a dose of 20 dpa, at which point
the irradiated yield's stress ceases to increase appreciably with
further dose accumulation. While the data at dose levels greater than
20 dpa does show a plateau behavior in the CGR, the staff's analyses of
that data suggests that areas of high CGR were averaged over the
industry calculation of CGR, which increases the uncertainty in the
high dose CGRs. Therefore, due to the limited data and the associated
high uncertainty at high fluence, the staff's confidence in CGRs at
dose levels greater than 20 dpa is low.
The second concern is the effects of uncertainty in the irradiated
yield strength value for an individual material-heat. This topic is
discussed in Section 4.7 of the technical basis report for Code Case N-
889. The NRC also conducted separate analyses. While the results of the
NRC's findings are generally consistent with the results in Section
4.7, the interpretation of their significance is not consistent. For
materials with yield strengths greater than 600 MPa (i.e., more highly-
irradiated materials), the expected CGR for a material with a yield
strength in the 95th percentile is less than two times the CGR
predicted by the Code Case, which is not a significant difference.
However, for materials with yield strength values less than 250 MPa
(i.e., unirradiated or minimally irradiated materials), the expected
CGR for a material in the 95th percentile can be more than five times
greater than the CGR predicted by the Code Case. Hence, the NRC's
concern is that the CGRs for individual low yield strength materials,
or materials with low fluence, could be significantly underpredicted by
the Code Case.
The final concern is related to the data used in the development of
the irradiated yield stress model. The methodology for addressing cold
work in this model was developed in MRP-135, Revision 1, while the
model itself was developed in MRP-211, Revision 0. The database
underlying the model included hundreds of yield strength measurements
on initially annealed and cold-worked Types 304, 316, and 347/348
stainless steel materials. However, most of the data were for annealed
Type 304 and cold-worked Type 316 stainless steels. Revision 1 of MRP-
211 contained additional yield strength data, including significantly
more data for cold-worked Types 304 and 347 stainless steel. The
authors of the Code Case, as documented in Section 4.5 of the
Additional Basis Report dated February 5, 2018, evaluated the Code Case
yield stress model with some of this additional data and found
agreement between the model and the additional data. However, the Code
Case authors excluded new data for cold-worked Type 304 and 347
stainless steel materials. Therefore, the technical basis document for
Code Case N-889 does not directly address whether cold-worked Type 304
and 347 (non-Molybdenum bearing) materials are adequately predicted by
the irradiated yield strength model in the Code Case. Therefore, the
NRC is proposing three conditions on this Code Case.
The first proposed condition states that this Code Case may not be
applied for neutron exposures greater than 20 dpa. This condition
addresses the NRC concern that there is sparse data with high
uncertainty beyond 20 dpa. Given that the predicted CGR saturates at
higher fluence, this condition prevents potential underprediction of
the CGR in this fluence regime.
The second proposed condition states that at dose levels below 0.75
dpa, the user must use the higher of the Code Case N-889 or the Section
XI, Nonmandatory Appendix C, C-8520 CGR predictions. This condition
addresses the NRC concern related to possible underprediction of CGR in
Code Case N-889 for materials with calculated irradiated yield strength
less than 250 MPa.
The final proposed condition states that the irradiated yield
stress model for cold-worked Molybdenum bearing materials must be used
for cold-worked non-Molybdenum bearing stainless steels (including Type
204 and 247 stainless steels). This condition addresses the NRC concern
that data for cold-worked non-Molybdenum bearing steels were not
appropriately considered during development of Code Case N-889. The NRC
performed its own evaluation of cold-worked Type 304 and 347 stainless
steels in the MRP-211 database and found that the yield strength was
better predicted by the Code Case's Molybdenum bearing model than with
the Code Case's non-Molybdenum bearing model.
Code Case N-890 [Supplement 0, 2019 Edition]
Type: New.
Title: Materials Exempted From G-2110(b) Requirements, Section XI,
Division 1.
Code Case N-890 provides an alternative to Section XI, G-2110(b)
which removes the requirement of, ``obtaining fracture toughness data
for at least three heats,'' for using the static fracture toughness
curve (KIc) curve for specific materials with a minimum
specified yield strength at room temperature between 50 kilopound per
square inch (ksi) and 90 ksi. Code Case N-890 would allow the toughness
of four ferritic steels (SA-508 Grade 2 Class 2, SA-508 Grade 3 Class
2, SA-533 Type A Class 2 and SA-533 Type B Class 2) with specified
minimum yield strength greater than 50 ksi to be characterized by
Figure G-2110-1 (i.e., the Section XI KIc curve).
The NRC identified one technical concern when reviewing the
technical basis of this Code Case. The technical basis provided
appropriate data to justify use of the KIc curve for several
materials listed in the Code Case. However, for SA-533 Type B, Class 2
materials, the NRC observed that in the technical basis document, there
is no fracture toughness data associated with the weld and heat
affected zone to support exclusion of the fracture toughness testing
requirements for these materials.
[[Page 7832]]
As such, the proposed NRC condition requires the user to comply
with the provisions of Section III, NB-2300 and Section III, G-2110(b)
to demonstrate the applicability of the ASME KIc curve to
SA-533 Type B, Class 2 material. These provisions require the user to
generate the necessary toughness data to demonstrate that the ASME
KIc curve is a conservative representation of the actual
material toughness.
3. ASME Operation and Maintenance Code Cases (DG-1368/RG 1.192)
Code Case OMN-1, Revision 2 [2020 Edition]
Type: Reaffirmed.
Title: Alternative Rules for Preservice and Inservice Testing of
Active Electric Motor-Operated Valve Assemblies in Light-Water Reactor
Power Plants.
The proposed conditions on Code Case OMN-1, Revision 2 [2020
Edition] are identical to the conditions on OMN-1, Revision 2 [2017
Edition] that were approved by the NRC in Revision 3 of RG 1.192. The
OMN-1, Revision 2 was reaffirmed by the ASME in the 2020 Edition with
no change to the Code Case. Therefore, the conditions would be retained
in Revision 4 of RG 1.192.
Code Case OMN-3 [2020 Edition]
Type: Reaffirmed.
Title: Requirements for Safety Significance Categorization of
Components Using Risk Insights for Inservice Testing of LWR Power
Plants.
The proposed conditions on Code Case OMN-3 [2020 Edition] are
identical to the conditions on OMN-3 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-3 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
Code Case OMN-4 [2020 Edition]
Type: Reaffirmed.
Title: Requirements for Risk Insights for Inservice Testing of
Check Valves at LWR Power Plants.
The proposed conditions on Code Case OMN-4 [2020 Edition] are
identical to the conditions on OMN-4 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-4 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
Code Case OMN-9 [2020 Edition]
Type: Reaffirmed.
Title: Use of a Pump Curve for Testing.
The proposed conditions on Code Case OMN-9 [2020 Edition] are
identical to the conditions on OMN-9 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-9 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
Code Case OMN-12 [2020 Edition]
Type: Reaffirmed.
Title: Alternative Requirements for Inservice Testing Using Risk
Insights for Pneumatically and Hydraulically Operated Valve Assemblies
in Light-Water Reactor Power Plants (OM-Code 1998, Subsection ISTC).
The proposed conditions on Code Case OMN-12 [2020 Edition] are
identical to the conditions on OMN-12 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-12 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
Code Case OMN-18 [2020 Edition]
Type: Reaffirmed.
Title: Alternate Testing Requirements for Pumps Tested Quarterly
Within 20% of Design Flow.
The proposed conditions on Code Case OMN-18 [2020 Edition] are
identical to the conditions on OMN-18 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-18 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
Code Case OMN-19 [2020 Edition]
Type: Reaffirmed.
Title: Alternative Upper Limit for the Comprehensive Pump Test.
The proposed conditions on Code Case OMN-19 [2020 Edition] are
identical to the conditions on OMN-19 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-19 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
Code Case OMN-20 [2020 Edition]
Type: Reaffirmed.
Title: Inservice Test Frequency.
The proposed conditions on Code Case OMN-20 [2020 Edition] are
identical to the conditions on OMN-20 [2017 Edition] that were approved
by the NRC in Revision 3 of RG 1.192. The OMN-20 was reaffirmed by the
ASME in the 2020 Edition with no change to the Code Case. Therefore,
the conditions would be retained in Revision 4 of RG 1.192.
C. ASME Code Cases Not Approved for Use (DG-1369/RG 1.193)
The ASME Code Cases that are currently issued by the ASME but not
approved for generic use by the NRC are listed in RG 1.193, ``ASME Code
Cases not Approved for Use.'' In addition to the ASME Code Cases that
the NRC has found to be technically or programmatically unacceptable,
RG 1.193 includes Code Cases on reactor designs for high-temperature
gas-cooled reactors and liquid metal reactors, reactor designs not
currently licensed by the NRC, and certain requirements in Section III,
Division 2, for submerged spent fuel waste casks, that are not endorsed
by the NRC. Regulatory Guide 1.193 complements RGs 1.84, 1.147, and
1.192. It should be noted that the NRC is not proposing to adopt any of
the Code Cases listed in RG 1.193.
IV. Section-by-Section Analysis
The following paragraphs in Sec. 50.55a would be revised as
follows:
Paragraph (a)(3) Introductory Text
This proposed rule would add a reference to NUREG-2228 that is
acceptable as specified in the conditions when implementing Code Cases
listed in certain NRC regulatory guides.
Paragraph (a)(3)(i)
This proposed rule would revise the reference to ``NRC Regulatory
Guide 1.84, Revision 38,'' by removing ``Revision 38'' and adding in
its place ``Revision 39'' and change the month and year for the
document's revision date.
Paragraph (a)(3)(ii)
This proposed rule would revise the reference to ``NRC Regulatory
Guide 1.147, Revision 19'' by removing ``Revision 19'' and adding in
its place ``Revision 20'' and change the month and year for the
document's revision date.
Paragraph (a)(3)(iii)
This proposed rule would revise the reference to ``NRC Regulatory
Guide 1.192, Revision 3'' by removing ``Revision 3'' and adding in its
place ``Revision 4'' and change the month and year for the document's
revision date.
Paragraph (a)(3)(iv)
This proposed rule would add new paragraph (a)(3)(iv) to reference
[[Page 7833]]
NUREG-2228, ``Weld Residual Stress Finite Element Analysis Validation:
Part II--Proposed Validation Procedure,'' dated July 2020, which is
referenced in RG 1.147, Revision 20.
Paragraph (b)(3)(iv), Table II
This proposed rule would capitalize the word ``(Years)'' in two of
the three column headings.
V. Regulatory Flexibility Certification
As required by the Regulatory Flexibility Act (5 U.S.C. 605(b)),
the Commission certifies that this rule, if adopted, will not have a
significant economic impact on a substantial number of small entities.
This proposed rule affects only the licensing and operation of nuclear
power plants. The companies that own these plants do not fall within
the scope of the definition of ``small entities'' set forth in the
Regulatory Flexibility Act or the size standards established by the NRC
(10 CFR 2.810).
VI. Regulatory Analysis
The NRC has prepared a draft regulatory analysis on this proposed
regulation. The analysis examines the costs and benefits of the
alternatives considered by the NRC. The NRC requests public comment on
the draft regulatory analysis. The regulatory analysis is available as
indicated in the ``Availability of Documents'' section of this
document. Comments on the draft analysis may be submitted to the NRC as
indicated under the ADDRESSES section of this document.
VII. Backfitting and Issue Finality
The provisions in this proposed rule would allow licensees and
applicants to voluntarily apply NRC-approved Code Cases, sometimes with
NRC-specified conditions. The approved Code Cases are listed in three
RGs that are proposed to be incorporated by reference into Sec.
50.55a. An applicant's or a licensee's voluntary application of an
approved Code Case does not constitute backfitting, because there is no
imposition of a new requirement or new position.
Similarly, voluntary application of an approved Code Case by a 10
CFR part 52 applicant or licensee does not represent NRC imposition of
a requirement or action, and therefore is not inconsistent with any
issue finality provision in 10 CFR part 52. For these reasons, the NRC
finds that this proposed rule does not involve any provisions requiring
the preparation of a backfit analysis or documentation demonstrating
that one or more of the issue finality criteria in 10 CFR part 52 are
met.
VIII. Plain Writing
The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal
agencies to write documents in a clear, concise, and well-organized
manner. The NRC has written this document to be consistent with the
Plain Writing Act as well as the Presidential Memorandum, ``Plain
Language in Government Writing,'' published June 10, 1998 (63 FR
31883). The NRC requests comment on this document with respect to the
clarity and effectiveness of the language used.
IX. Environmental Assessment and Proposed Finding of No Significant
Environmental Impact
The Commission has determined under the National Environmental
Policy Act of 1969, as amended, and the Commission's regulations in
subpart A of 10 CFR part 51, that this rule, if adopted, would not be a
major Federal action significantly affecting the quality of the human
environment; therefore, an environmental impact statement is not
required.
The determination of this environmental assessment is that there
will be no significant effect on the quality of the human environment
from this action. Interested parties should note, however, that
comments on any aspect of this environmental assessment may be
submitted to the NRC as indicated under the ADDRESSES section of this
document.
As voluntary alternatives to the ASME Code, NRC-approved Code Cases
provide an equivalent level of safety. Therefore, the probability or
consequences of accidents is not changed. There are also no
significant, non-radiological impacts associated with this action
because no changes would be made affecting non-radiological plant
effluents and because no changes would be made in activities that would
adversely affect the environment. The determination of this
environmental assessment is that there will be no significant offsite
impact to the public from this action.
X. Paperwork Reduction Act Statement
This proposed rule contains new or amended collections of
information subject to the Paperwork Reduction Act of 1995 (44 U.S.C.
3501 et seq.). This proposed rule has been submitted to the Office of
Management and Budget (OMB) for approval of the information
collections.
Type of submission, new or revision: Revision.
The title of the information collection: Domestic Licensing of
Production and Utilization Facilities: Updates to Incorporation by
Reference and Regulatory Guides.
The form number if applicable: Not applicable.
How often the collection is required: On occasion.
Who will be required or asked to report: Operating power reactor
licensees and applicants for power reactors under construction.
An estimate of the number of annual responses: -28 (reduction).
The estimated number of annual respondents: -28 (reduction).
An estimate of the total number of hours needed annually to
complete the requirement or request: -6,720 hours (reduction of
reporting and recordkeeping hours).
Abstract: This proposed rule is the latest in a series of
rulemakings that incorporate by reference the latest versions of
several RGs identifying new and revised unconditionally or
conditionally acceptable ASME Code Cases that are approved for use. The
incorporation by reference of these Code Cases will reduce the number
of alternative requests submitted by licensees under Sec. 50.55a(z) by
an estimated 28 requests annually.
The NRC is seeking public comment on the potential impact of the
information collections contained in this proposed rule and on the
following issues:
1. Is the proposed information collection necessary for the proper
performance of the functions of the NRC, including whether the
information will have practical utility?
2. Is the estimate of the burden of the proposed information
collection accurate?
3. Is there a way to enhance the quality, utility, and clarity of
the information to be collected?
4. How can the burden of the proposed information collection on
respondents be minimized, including the use of automated collection
techniques or other forms of information technology?
A copy of the OMB clearance package and proposed rule is available
in ADAMS under Accession No. ML20132A240 or can obtained free of charge
by contacting the NRC's Public Document reference staff at 1-800-397-
4209, 301-415-4737, or by email to [email protected]. You may
obtain information and comment submissions related to the OMB clearance
package by searching on https://www.regulations.gov under Docket ID
NRC-2017-0025.
[[Page 7834]]
You may submit comments on any aspect of these proposed information
collections, including suggestions for reducing the burden and on the
four issues, by the following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2017-0025.
Mail comments to: FOIA, Library, and Information
Collections Branch, Office of the Chief Information Officer, Mail Stop:
T-6 A10M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001
or to the OMB reviewer at: OMB Office of Information and Regulatory
Affairs (3150-0011), Attn: Desk Officer for the Nuclear Regulatory
Commission, 725 17th Street NW, Washington, DC 20503; email:
[email protected].
Submit comments on this collection of information by March 4, 2021.
Comments received after this date will be considered if it is practical
to do so, but the NRC staff is able to ensure consideration only for
comments received on or before this date.
Public Protection Notification
The NRC may not conduct or sponsor, and a person is not required to
respond to, a collection of information unless the document requesting
or requiring the collection displays a currently valid OMB control
number.
XI. Voluntary Consensus Standards
The National Technology Transfer and Advancement Act of 1995,
Public Law 104-113, requires that Federal agencies use technical
standards that are developed or adopted by voluntary consensus
standards bodies unless using such a standard is inconsistent with
applicable law or is otherwise impractical. In this proposed rule, the
NRC is continuing to use the ASME BPV and OM Code Cases, which are
ASME-approved voluntary alternatives to compliance with various
provisions of the ASME BPV and OM Codes. The NRC's approval of the ASME
Code Cases is accomplished by amending the NRC's regulations to
incorporate by reference the latest revisions of the following, which
are the subject of this rulemaking, into Sec. 50.55a: RG 1.84,
Revision 39; RG 1.147, Revision 20; RG 1.192, Revision 4; and NUREG-
2228. The RGs list the ASME Code Cases that the NRC has approved for
use. The ASME Code Cases are national consensus standards as defined in
the National Technology Transfer and Advancement Act of 1995 and OMB
Circular A-119. The ASME Code Cases constitute voluntary consensus
standards, in which all interested parties (including the NRC and
licensees of nuclear power plants) participate. The NRC invites comment
on the applicability and use of other standards.
XII. Incorporation by Reference--Reasonable Availability to Interested
Parties
The NRC proposes to incorporate by reference three NRC RGs that
list new and revised the ASME Code Cases that the NRC has approved as
voluntary alternatives to certain provisions of NRC-required Editions
and Addenda of the ASME BPV Code and the ASME OM Code. The draft
regulatory guides, DG-1366, DG-1367, and DG-1368, will correspond to
final RG 1.84, Revision 39; RG 1.147, Revision 20; and RG 1.192,
Revision 4, respectively. The NRC also proposes to incorporate by
reference NUREG-2228, which is referenced in DG-1367 (RG 1.147,
Revision 20). As described in this document, this report pertains to a
proposed condition on Code Case N-847.
The NRC is required by law to obtain approval for incorporation by
reference from the Office of the Federal Register (OFR). The OFR's
requirements for incorporation by reference are set forth in 1 CFR part
51. On November 7, 2014, the OFR adopted changes to its regulations
governing incorporation by reference (79 FR 66267). The OFR regulations
require an agency to include in a proposed rule a discussion of the
ways that the materials the agency proposes to incorporate by reference
are reasonably available to interested parties or how it worked to make
those materials reasonably available to interested parties. The
discussion in this section complies with the requirement for proposed
rules as set forth in 1 CFR 51.5(a)(1).
The NRC considers ``interested parties'' to include all potential
NRC stakeholders, not only the individuals and entities regulated or
otherwise subject to the NRC's regulatory oversight. These NRC
stakeholders are not a homogenous group, so the considerations for
determining ``reasonable availability'' vary by class of interested
parties. The NRC identified six classes of interested parties with
regard to the material to be incorporated by reference in an NRC rule:
Individuals and small entities regulated or otherwise
subject to the NRC's regulatory oversight. This class includes
applicants and potential applicants for licenses and other NRC
regulatory approvals, and who are subject to the material to be
incorporated by reference. In this context, ``small entities'' has the
same meaning as set out in 10 CFR 2.810.
Large entities otherwise subject to the NRC's regulatory
oversight. This class includes applicants and potential applicants for
licenses and other NRC regulatory approvals, and who are subject to the
material to be incorporated by reference. In this context, a ``large
entity'' is one that does not qualify as a ``small entity'' under 10
CFR 2.810.
Non-governmental organizations with institutional
interests in the matters regulated by the NRC.
Other Federal agencies, states, local governmental bodies
(within the meaning of 10 CFR 2.315(c)).
Federally-recognized and State-recognized Indian tribes.
Members of the general public (i.e., individual,
unaffiliated members of the public who are not regulated or otherwise
subject to the NRC's regulatory oversight) who need access to the
materials that the NRC proposes to incorporate by reference in order to
participate in the rulemaking.
The NUREG-2228 and three draft RGs that the NRC proposes to
incorporate by reference in this proposed rule are available without
cost and can be read online or downloaded online. The NUREG-2228 and
draft RGs can be viewed, by appointment, at the NRC Technical Library,
which is located at Two White Flint North, 11545 Rockville Pike,
Rockville, Maryland 20852; telephone: 301-415-7000; email:
[email protected]. The final RGs, if approved by the OFR for
incorporation by reference, will also be available for inspection at
the OFR, as described in 10 CFR 50.55a(a).
Because access to the three draft regulatory guides, and
eventually, the final regulatory guides, are available in various forms
at no cost, the NRC determines that the three draft regulatory guides,
DG-1366, DG-1367, and DG-1368, and final RG 1.84, Revision 39; RG
1.147, Revision 20; and RG 1.192, Revision 4, once approved by the OFR
for incorporation by reference, are reasonably available to all
interested parties.
XIII. Availability of Documents
The documents identified in the following tables are available to
interested persons through one or more of the following methods, as
indicated. Throughout the development of this rule, the NRC may post
documents related to this rule, including public comments, on the
Federal rulemaking website at: https://www.regulations.gov under Docket
ID NRC-2017-0025. The Federal rulemaking website allows you
[[Page 7835]]
to receive alerts when changes or additions occur in a docket folder.
To subscribe: (1) Navigate to the docket folder (NRC-2017-0025); (2)
click the ``Sign up for Email Alerts'' link; and (3) enter your email
address and select how frequently you would like to receive emails
(daily, weekly, or monthly).
Table III--Rulemaking Related Documents
----------------------------------------------------------------------------------------------------------------
ADAMS Accession No. or Federal Register citation,
Document title or website
----------------------------------------------------------------------------------------------------------------
Final Rule -- ``Incorporation by Reference of ASME BPV and 68 FR 40469.
OM Code Cases,'' July 8, 2003.
Final Rule -- ``Incorporation by Reference of American 82 FR 32934.
Society of Mechanical Engineers Codes and Code Cases,''
July 18, 2017.
Zorita Internals Research Project (MRP-440) Testing of Available for purchase.
Highly-Irradiated Baffle Plate Material 3002016015 Final
Report, October 2019.
ASME Code, Section III, NB-2330, ``Test Requirements and Available for purchase.
Acceptance Standards,'' July 2017.
BWRVIP-75-A, ``BWR Vessel and Internals Project, Technical Available for purchase.
Basis for Revisions to Generic Letter 88-01 Inspection
Schedules,'' October 2005.
Final Rule -- ``Approval of American Society of Mechanical 85 FR 14736.
Engineers' Code Cases,'' March 16, 2020.
RG 1.193, ASME Code Cases Not Approved for Use, Revision 7 ML20120A627.
(DG-1369).
Rulemaking--Proposed Rule--Regulatory Analysis for the ML20133K152.
American Society of Mechanical Engineers Code Cases, RG
1.84, Rev 39; RG 1.147, Rev 20; RG 1.192, Rev 4; and RG
1.193, Rev 7.
GL-88-01, Supplement 1, ``NRC Position on Intergranular https://www.nrc.gov/reading-rm/doc-collections/gen-
Stress Corrosion Cracking (IGSCC) in BWR Austenitic comm/gen-letters/1988/gl88001s1.html.
Stainless Steel Piping (Generic Letter 88-01, Supplement
1),'' February 4, 1992.
GL-88-01, ``NRC Position on IGSCC in BWR Austenitic https://www.nrc.gov/reading-rm/doc-collections/gen-
Stainless Steel Piping (Generic Letter No. 88-01),'' comm/gen-letters/1988/gl88001.html.
January 25, 1988.
Final Rule--``Approval of American Society of Mechanical 85 FR 26540.
Engineers 2015-20017 Code Editions, Incorporataion by
Reference,'' May 4, 2020.
----------------------------------------------------------------------------------------------------------------
Documents Proposed To Be Incorporated by Reference
The NRC proposes to incorporate by reference three NRC RGs, as set
forth in Table IV, that list new and revised ASME Code Cases that the
NRC has approved as voluntary alternatives to certain provisions of
NRC-required Editions and Addenda of the ASME BPV Code and the ASME OM
Code. The NRC also proposes to incorporate by reference NUREG-2228, as
set forth in Table V, that is referenced within a condition in RG
1.147, Revision 20.
Table IV--Draft Regulatory Guides Proposed To Be Incorporated by Reference in 10 CFR 50.55a
----------------------------------------------------------------------------------------------------------------
Document title ADAMS Accession No./ Federal Register citation
----------------------------------------------------------------------------------------------------------------
RG 1.84, Design, Fabrication, and Materials Code Case ML20120A633.
Acceptability, ASME Section III, Revision 39, (DG-1366).
RG 1.147, Inservice Inspection Code Case Acceptability, ML20120A631.
ASME Section XI, Division 1, Revision 20, (DG-1367).
RG 1.192, Operation and Maintenance Code Case ML20120A629.
Acceptability, ASME OM Code, Revision 4, (DG-1368).
----------------------------------------------------------------------------------------------------------------
Table V--Related Documents Proposed To Be Incorporated by Reference in 10 CFR 50.55a
----------------------------------------------------------------------------------------------------------------
Document title ADAMS Accession No.
----------------------------------------------------------------------------------------------------------------
NUREG-2228, ``Weld Residual Stress Finite Element Analysis ML20212L592.
Validation: Part II--Proposed Validation Procedure,''
July 2020.
----------------------------------------------------------------------------------------------------------------
Code Cases for Approval in This Proposed Rule
The ASME BPV Code Cases that the NRC is proposing to approve as
alternatives to certain provisions of the ASME BPV Code, as set forth
in Table VI, are being made available by the ASME for read-only access
during the public comment period on https://go.asme.org/NRC-ASME-CC.
The ASME OM Code Cases that the NRC is proposing to approve as
alternatives to certain provisions of the ASME OM Code, as set forth in
Table VI, are being made available for read-only access during the
public comment period by the ASME on https://go.asme.org/NRC-ASME-CC.
The ASME is making the Code Cases listed in Table VI available for
limited, read-only access at the request of the NRC. The NRC believes
that stakeholders need to be able to read these Code Cases in order to
provide meaningful comment on the three RGs (listed in Table IV) that
the NRC is proposing to incorporate by reference into Sec. 50.55a. It
is the NRC's position that the listed Code Cases, as modified by any
conditions contained in the three RGs and thus serving as alternatives
to requirements in Sec. 50.55a, are legally-binding regulatory
requirements. An applicant or licensee must comply with a listed Code
Case and any conditions to be within the scope of the NRC's approval of
the Code Case as a voluntary alternative for use. These requirements
cannot be fully understood without knowledge of the Code Case to which
the proposed condition applies, and to this end, the NRC has requested
that the
[[Page 7836]]
ASME provide limited, read-only access to the Code Cases in order to
facilitate meaningful public comment.
Table VI--ASME Code Cases Proposed for NRC Approval
----------------------------------------------------------------------------------------------------------------
Code Case No. Supplement Title
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code Section III
----------------------------------------------------------------------------------------------------------------
N-71-20............................... 6 (2015 Edition)........................ Additional Materials for
Subsection NF, Class 1, 2, 3,
and MC Supports Fabricated by
Welding, Section III,
Division 1.
N-155-3............................... 5 (2015 Edition)........................ Fiberglass Reinforced
Thermosetting Resin Pipe,
Section III, Division 1.
N-249-17.............................. 0 (2019 Edition)........................ Additional Materials for
Subsection NF, Classes 1, 2,
3, and MC Supports Fabricated
without Welding Section III,
Division 1.
N-539-1............................... 0 (2017 Edition)........................ UNS N08367 in Class 2 and 3
Valves, Section III, Division
1.
N-692-1............................... 6 (2015 Edition)........................ Use of Standard Welding
Procedures, Section III,
Division 1.
N-721-1............................... 5 (2017 Edition)........................ Alternative Rules for Linear
Piping Supports, Section III,
Division 1.
N-755-4............................... 1 (2017 Edition)........................ Use of Polyethylene (PE) Class
3 Plastic Pipe, Section III,
Division 1.
N-779................................. 9 (2007 Edition)........................ Alternative Rules for
Simplified Elastic-Plastic
Analysis Class 1, Section
III, Division 1.
N-801-3............................... 1 (2017 Edition)........................ Rules for Repair of N-Stamped
Class 1, 2, and 3 Components,
Section III, Division 1.
N-822-4............................... 7 (2015 Edition)........................ Application of the ASME
Certification Mark, Section
III, Divisions 1, 2, 3, and
5.
N-852................................. 0 (2015 Edition)........................ Application of the ASME NPT
Stamp, Section III, Divisions
1, 2, 3, and 5.
N-855................................. 2 (2015 Edition)........................ SB-148 C95800 Valves for Class
3 Construction, Section III,
Division 1.
N-856................................. 2 (2015 Edition)........................ SA-494 Grade CW-12MW (UNS
N30002) Nickel Alloy Castings
for Construction of NPS 2\1/
2\ and Smaller Flanged Valves
for Class 3 Construction,
Section III, Division 1.
N-859................................. 5 (2015 Edition)........................ Construction of ASME B16.9
Wrought Buttwelding Fittings
and ASME B16.11 Forged
Fittings Made From SB-366 UNS
N04400 Material for Section
III, Class 3 Construction,
Section III, Division 1.
N-863-1............................... 1 (2017 Edition)........................ Post Weld Heat Treatment
(PWHT) of Valve Seal Welds
for P4 and P5A Materials,
Section III, Division 1.
N-866................................. 0 (2017 Edition)........................ Alternative Materials for
Construction of Section III,
Class 2 Vessels, Section III,
Division 1.
N-870-1............................... 4 (2017 Edition)........................ Rules for the Elimination of
External Surface Defects on
Class 1, 2, and 3 Piping,
Pumps, or Valves After
Component Stamping and Prior
to Completion of the N-3 Data
Report, Section III, Division
1.
N-879................................. 1 (2017 Edition)........................ Use of Micro-Alloyed Carbon
Steel Bar in Patented
Mechanical Joints and
Fittings, Classes 1, 2, and
3, Section III, Division 1.
N-883................................. 5 (2017 Edition)........................ Construction of Items Prior to
the Establishment of a
Section III, Division 1
Owner, Section III, Division
1.
N-884................................. 0 (2019 Edition)........................ Procedure to Determine Strain
Rate for Use with the
Environmental Fatigue Design
Curve Method and the
Environmental Fatigue
Correction Factor, Fen,
Method as Part of an
Environmental Fatigue
Evaluation for Components
Analyzed per the NB-3200
Rules, Section III, Division
1.
N-886................................. 6 (2017 Edition)........................ Use of Polyethylene Pipe for
Class 3, Section III,
Division 1.
N-887................................. 6 (2017 Edition with errata dated August Alternatives to the
30, 2019). Requirements of NB-4424.2(a),
Figure NB-4250-2, and Figure
NB-4250-3 Section III,
Division 1.
N-891................................. 0 (2019 Edition)........................ Alternative Requirements to
Appendix XXVI, XXVI-2400,
XXVI-4130, and XXVI-4131 for
Inspection and Repair of
Indentations for Polyethylene
Pipe and Piping Components,
Section III, Division 1.
----------------------------------------------------------------------------------------------------------------
Boiler and Pressure Vessel Code, Section XI
----------------------------------------------------------------------------------------------------------------
N-513-5............................... 6 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of Flaws
in Moderate Energy Class 2 or
3 Piping and Gate Valves,
Section XI, Division 1.
N-516-5............................... 6 (2015 Edition)........................ Underwater Welding, Section
XI, Division 1.
N-561-3............................... 0 (2019 Edition)........................ Alternative Requirements for
Wall Thickness Restoration of
Class 2 and High Energy Class
3 Carbon Steel Piping,
Section XI, Division 1.
N-638-10.............................. 1 (2019 Edition)........................ Similar and Dissimilar Metal
Welding Using Ambient
Temperature Machine GTAW
Temper Bead Technique,
Section XI, Division 1.
N-653-2............................... 1 (2017 Edition)........................ Qualification Requirements for
Full Structural Overlaid
Wrought Austenitic Piping
Welds, Section XI, Division
1.
N-702-1............................... 1 (2019 Edition)........................ Alternative Requirements for
Boiling Water Reactor (BWR)
Nozzle Inner Radius and
Nozzle-to-Shell Welds,
Section XI, Division 1.
N-705-1............................... 2 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of
Degradation in Moderate
Energy Class 2 or 3 Vessels
and Tanks, Section XI,
Division 1.
N-716-2............................... 0 (2017 Edition)........................ Alternative Piping
Classification and
Examination Requirements,
Section XI, Division 1.
N-766-3............................... 2 (2017 Edition)........................ Nickel Alloy Reactor Coolant
Inlay and Onlay for
Mitigation of PWR Full
Penetration Circumferential
Nickel Alloy Dissimilar Metal
Welds in Class 1 Items,
Section XI, Division 1.
N-768................................. 0 (2019 Edition)........................ Alternative Volumetric
Coverage Requirements for
Ultrasonic Examination of
Class 1 and 2 Pressure Vessel
Weld Joints Greater Than 2
in. (50 mm) in Thickness,
Section XI, Division 1.
N-786-3............................... 1 (2017 Edition)........................ Alternative Requirements for
Sleeve Reinforcement of Class
2 and 3 Moderate Energy
Carbon Steel Piping, Section
XI, Division 1.
N-789-3............................... 1 (2017 Edition)........................ Alternative Requirements for
Pad Reinforcement of Class 2
and 3 Moderate Energy Carbon
Steel Piping for Raw Water
Service, Section XI, Division
1.
[[Page 7837]]
N-809................................. 2 (2015 Edition)........................ Reference Fatigue Crack Growth
Rate Curves for Austenitic
Stainless Steels in
Pressurized Reactor Water
Environments, Section XI,
Division 1.
N-831-1............................... 1 (2019 Edition)........................ Ultrasonic Examination in Lieu
of Radiography for Welds in
Ferritic or Austenitic Pipe,
Section XI, Division 1.
N-845-1............................... 6 (2015 Edition)........................ Qualification Requirements for
Bolts and Studs, Section XI,
Division 1.
N-847................................. 0 (2017 Edition)........................ Partial Excavation and
Deposition of Weld Metal for
Mitigation of Class 1 Items,
Section XI, Division 1.
N-848-1............................... 0 (2017 Edition)........................ Alternative Characterization
Rules for Quazi-Laminar
Flaws, Section XI, Division
1.
N-851................................. 0 (2015 Edition)........................ Alternate Method for
Establishing the Reference
Temperature for Pressure
Retaining Materials, Section
XI, Division 1.
N-858................................. 2 (2017 Edition)........................ Alternative Volumetric
Coverage Requirements for
Ultrasonic Examination of
Class 1 Nozzle-to-Vessel
Welds, Section XI, Division
1.
N-864................................. 2 (2017 Edition)........................ Reactor Vessel Threads in
Flange Examinations, Section
XI, Division 1.
N-865................................. 2 (2017 Edition)........................ Alternative Requirements for
Pad Reinforcement of Class 2
and 3 Atmospheric Storage
Tanks, Section XI, Division
1.
N-867................................. 0 (2017 Edition)........................ Clarification of NDE Practical
Examination Requirements,
Section XI, Division 1.
N-869................................. 6 (2017 Edition)........................ Evaluation Criteria for
Temporary Acceptance of Flaws
in Class 2 or 3 Piping,
Section XI, Division 1.
N-873................................. 1 (2017 Edition)........................ Examination Requirements for
the Core Makeup Tanks,
Section XI, Division 1.
N-874................................. 7 (2017 Edition)........................ Temporary Acceptance of
Leakage Through Brazed Joints
of Class 3 Copper, Copper-
Nickel, and Nickel-Copper
Moderate Energy Piping,
Section XI, Division 1.
N-876................................. 2 (2017 Edition)........................ Austenitic Stainless Steel
Cladding and Nickel Base
Cladding Using Ambient
Temperature Automatic or
Machine Dry Underwater Laser
Beam Welding (ULBW) Temper
Bead Technique, Section XI,
Division 1.
N-877................................. 2 (2017 Edition)........................ Alternative Characterization
Rules for Multiple Subsurface
Radially Oriented Planar
Flaws, Section XI, Division
1.
N-878................................. 1 (2017 Edition)........................ Alternative to QA Program
Requirements of IWA-4142,
Section XI, Division 1.
N-880................................. 2 (2017 Edition)........................ Alternative to Procurement
Requirements of IWA-4143 for
Small Nonstandard Welded
Fittings, Section XI,
Division 1.
N-882................................. 6 (2017 Edition)........................ Alternative Requirements for
Attaching Nonstructural
Electrical Connections to
Class 2 and 3 Components,
Section XI, Division 1.
N-885................................. 0 (2019 Edition)........................ Alternative Requirements for
Table IWB-2500-1, Examination
Category B-N-1, Interior of
Reactor Vessel, Category B-N-
2, Welded Core Support
Structures and Interior
Attachments to Reactor
Vessels, Category B-N-3,
Removable Core Support
Structures Section XI,
Division 1.
N-889................................. 7 (2017 Edition)........................ Reference Stress Corrosion
Crack Growth Rate Curves for
Irradiated Austenitic
Stainless Steel in Light-
Water Reactor Environments,
Section XI, Division 1.
N-890................................. 0 (2019 Edition)........................ Materials Exempted From G-
2110(b) Requirement, Section
XI, Division 1.
N-892................................. 0 (2019 Edition)........................ Alternative Requirement for
Form OAR-1, Owner's Activity
Report, Completion Time,
Section XI, Division 1.
----------------------------------------------------------------------------------------------------------------
Operation and Maintenance Code
----------------------------------------------------------------------------------------------------------------
Code Case No. Edition \4\ Title
----------------------------------------------------------------------------------------------------------------
OMN-13, Revision 3.................... 2020 Edition............................ Performance-Based Requirements
for Extending Snubber
Inservice Visual Examination
Interval at LWR Power Plants.
OMN-15, Revision 3.................... 2020 Edition............................ Performance-Based Requirements
for Extending the Snubber
Operational Readiness Testing
Interval at LWR Power Plants.
OMN-17, Revision 1.................... 2020 Edition............................ Alternative Requirements for
Testing ASME Class 1 Pressure
Relief/Safety Valves.
OMN-22................................ 2020 Edition............................ Smooth Running Pumps.
OMN-23................................ 2020 Edition............................ Alternative Requirements for
Testing Pressure Isolation
Valves.
OMN-24................................ 2020 Edition............................ Alternative Requirements for
Testing ASME Class 2 and 3
Pressure Relief Valves (For
Relief Valves in a Group of
One).
OMN-25................................ 2020 Edition............................ Alternative Requirements for
Testing Appendix I Pressure
Relief Valves.
OMN-26................................ 2020 Edition............................ Alternate Risk-Informed and
Margin Based Rules for
Inservice Testing of Motor
Operated Valves.
OMN-27................................ 2020 Edition............................ Alternative Requirements for
Testing Category A Valves
(Non-PIV/CIV).
----------------------------------------------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\4\ The column labelled ``Edition'' in this table refers to the
point in time a Code Case was issued. For example, an entry
associated with the 2017 Edition means the Code Case was issued at
the same time as the 2017 Edition of the Code.
---------------------------------------------------------------------------
For the reasons set out 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. 553, the NRC is proposing to
adopt 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:
[[Page 7838]]
Authority: Atomic Energy Act of 1954, secs. 11, 101, 102, 103,
104, 105, 108, 122, 147, 149, 161, 181, 182, 183, 184, 185, 186,
187, 189, 223, 234 (42 U.S.C. 2014, 2131, 2132, 2133, 2134, 2135,
2138, 2152, 2167, 2169, 2201, 2231, 2232, 2233, 2234, 2235, 2236,
2237, 2239, 2273, 2282); Energy Reorganization Act of 1974, secs.
201, 202, 206, 211 (42 U.S.C. 5841, 5842, 5846, 5851); Nuclear Waste
Policy Act of 1982, sec. 306 (42 U.S.C. 10226); National
Environmental Policy Act of 1969 (42 U.S.C. 4332); 44 U.S.C. 3504
note; Sec. 109, Pub. L. 96-295, 94 Stat. 783.
0
2. In Sec. 50.55a:
0
a. Revise paragraph (a)(3) introductory text;
0
b. In paragraph (a)(3)(i), remove the phrase ``Revision 38'' and add in
its place the phrase ``Revision 39'' and remove the phrase ``October
2019'' and add in its place the phrase ``MONTH/YEAR'';
0
c. In paragraph (a)(3)(ii), remove the phrase ``Revision 19'' and add
in its place the phrase ``Revision 20'' and remove the phrase ``October
2019'' and add in its place the phrase ``MONTH/YEAR'';
0
d. In paragraph (a)(3)(iii), remove the phrase ``Revision 3'' and add
in its place the phrase ``Revision 4'' and remove the phrase ``October
2019'' and add in its place the phrase ``MONTH/YEAR'';
0
e. Add paragraph (a)(3)(iv); and
0
f. In paragraph (b)(3)(iv), Table II, remove the word ``(years)'' in
the second and third column headings and add in their places the word
``(Years)''.
The revision and addition read as follows:
Sec. 50.55a Codes and standards.
(a) * * *
(3) U.S. Nuclear Regulatory Commission (NRC) Public Document Room,
11555 Rockville Pike, Rockville, Maryland 20852; telephone: 1-800-397-
4209; email: [email protected]; https://www.nrc.gov/reading-rm/doc-collections/reg-guides/. The use of Code Cases listed in the NRC
regulatory guides in paragraphs (a)(3)(i) through (iii) of this section
is acceptable with the specified conditions in those guides when
implementing the editions and addenda of the ASME BPV Code and ASME OM
Code incorporated by reference in paragraph (a)(1) of this section. The
NRC report in paragraph (a)(3)(iv) of this section is acceptable as
specified in the conditions when implementing Code Cases listed in the
NRC regulatory guides in paragraphs (a)(3)(i) through (iii).
* * * * *
(iv) NUREG-2228. NUREG-2228, ``Weld Residual Stress Finite Element
Analysis Validation: Part II--Proposed Validation Procedure,'' dated
July 2020, which is referenced in RG 1.147, Revision 20.
* * * * *
Dated December 23, 2020.
For the Nuclear Regulatory Commission.
Ho K. Nieh,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2021-00890 Filed 2-1-21; 8:45 am]
BILLING CODE 7590-01-P