[Federal Register Volume 68, Number 189 (Tuesday, September 30, 2003)]
[Notices]
[Pages 56338-56340]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-24669]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-338 and 50-339]
Virginia Electric and Power Company, North Anna Power Station,
Units 1 and 2; Exemption
1.0 Background
The Virginia Electric and Power Company (the licensee) is the
holder of Renewed Facility Operating License Nos. NPF-4 and NPF-7,
which authorize operation of the North Anna Power Station, Units 1 and
2. The licenses provide, among other things, that the facilities are
subject to all rules, regulations, and orders of the U.S. Nuclear
Regulatory Commission (NRC, the Commission) now or hereafter in effect.
The North Anna units are pressurized-water reactors located in
Louisa County in the Commonwealth of Virginia.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR), Section
50.44, ``Standard for Combustion Gas Control in Light-Water-Cooled
Power Reactors,'' requires, in part, reactors fueled with Zircaloy or
ZIRLO cladding to provide means to control any hydrogen gas that may be
generated after a postulated loss-of-coolant accident (LOCA). 10 CFR
50.46, ``Acceptance Criteria for Emergency Core Cooling Systems for
Light Water Nuclear Power Reactors,'' requires that emergency core
cooling systems (ECCSs) for reactors containing fuel with Zircaloy or
ZIRLO fuel cladding material be designed such that their performance,
as calculated as set forth in that section, meets specified acceptance
criteria. Finally, 10 CFR Part 50, Appendix K, ``ECCS Evaluation
Models,'' requires that the Baker-Just equation be used to predict the
rates of energy release, hydrogen concentration, and cladding oxidation
from the metal water reaction for reactors using Zircaloy fuel
cladding.
By letter dated March 28, 2002, as supplemented by letters dated
May 13, June 19, and November 15, 2002, and May 6, May 9, May 27, June
11 (2 letters), July 18, August 26, September 4, and September 5, 2003,
the licensee requested an exemption from the requirements of 10 CFR
50.44 and 10 CFR 50.46 to use an advanced zirconium-based alloy,
designated as M5, for the fuel cladding material instead of the ZIRLO
or Zircaloy fuel cladding material specified in these regulations. The
licensee's exemption request was submitted in conjunction
[[Page 56339]]
with an application for license amendments to use Framatome Advanced
Mark-BW fuel containing M5 cladding material at North Anna, Units 1 and
2. The proposed amendment is currently under NRC staff review.
Together, the exemption and amendments would allow Framatome Advanced
Mark-BW fuel with M5 cladding to be used at North Anna, Units 1 and 2.
In addition, in accordance with 10 CFR 50.12(a), the NRC staff,
upon its own initiative, has developed an exemption from the
requirements of 10 CFR part 50, appendix K, with respect to the use of
Framatome Advanced Mark-BW fuel containing M5 cladding at North Anna,
Units 1 and 2. In its submittal dated March 28, 2002, the licensee
indicated that an exemption from 10 CFR part 50, appendix K, was not
necessary to use M5 fuel cladding since Framatome Advanced Nuclear
Power (ANP) had demonstrated in the NRC staff-approved Topical Report
BAW-10227P, ``Evaluation of Advanced Cladding and Structural Material
(M5) in PWR Reactor Fuel,'' dated February 11, 2000, that the Baker-
Just equation can be used to conservatively predict the metal-water
reaction rates for M5 fuel cladding. However, after reviewing its
Safety Evaluation Report (SER) dated February 4, 2000, for Topical
Report BAW-10227P, the NRC staff has determined that an exemption from
10 CFR part 50, appendix K, was also needed in order to use M5 fuel
cladding at North Anna, Units 1 and 2. The NRC staff's rationale for
developing this exemption on its own initiative is explained in the
following section.
3.0 Discussion
Pursuant to 10 CFR 50.12, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of 10 CFR part 50 when (1) the exemptions are
authorized by law, will not present an undue risk to public health or
safety, and are consistent with the common defense and security; and
(2) special circumstances are present. In accordance with 10 CFR
50.12(a)(2)(ii), special circumstances exist whenever application of a
particular regulation under the circumstances is not necessary to
achieve the underlying purpose of the rule.
The licensee proposes to use M5 material for fuel rod cladding and
fuel assembly structural tubing and grids at North Anna, Units 1 and 2.
On February 4, 2000, the NRC staff approved Topical Report BAW-10227P.
This topical report provided the basis for the use of Framatome ANP's
M5 cladding and structural material in pressurized-water reactor cores.
In its SER dated February 4, 2000, for Topical Report BAW-10227P, the
NRC staff concluded that M5 properties and the mechanical design
methodology as defined in this topical report, ``are in accordance with
Standard Review Plan Section 4.2, 10 CFR 50.46, and 10 CFR part 50,
appendix K, and therefore are acceptable for reload licensing
applications up to rod average burnup levels of 62,000 MWd/MTU and
60,000 MWd/MTU for Mark B and Mark-BW fuel designs, respectively.'' The
NRC staff's SER and the approved topical report were published on
February 11, 2000, as Topical Report BAW-10227P-A. By letter dated
March 28, 2002, the licensee presented a mixed core analysis
methodology and a transition core penalty to account for the
differences in the core geometry between the Mark-BW fuel and the
Advanced Mark-BW fuel proposed for use at North Anna, Units 1 and 2.
The NRC staff has determined that Topical Report BAW-10227P-A is
applicable to the use of Advanced Mark-BW fuel at North Anna, Units 1
and 2, because the core geometrical differences are consistent with the
range of conditions for which analyses of fuel performance are
documented in the NRC staff-approved topical report regarding the use
of M5 fuel cladding.
The underlying purpose of 10 CFR 50.44 is to ensure that means are
provided for control of hydrogen gas following a LOCA. However, this
rule applies only to reactors using Zircaloy or ZIRLO cladding. The
licensee has provided means for controlling hydrogen gas and has
previously considered the potential for hydrogen gas generation
stemming from a metal-water reaction. Furthermore, in its NRC staff-
approved Topical Report BAW-10227P-A, Appendix A, Framatome ANP
demonstrated that M5 fuel cladding material is similar in chemical
composition to Zircaloy cladding. Accordingly, this chemical similarity
ensures that the previous calculations of hydrogen production resulting
from metal-water reaction will not be significantly changed. As such,
application of 10 CFR 50.44 is not necessary for the licensee to
achieve its underlying purpose in these circumstances.
The underlying purpose of 10 CFR 50.46 is to ensure that facilities
meet appropriate acceptance criteria for calculated ECCS performance.
However, this rule applies only to reactors using Zircaloy or ZIRLO
cladding. In its topical report, Framatome ANP demonstrated that ECCS
acceptance criteria are also applicable to reactors that use M5 fuel
rod cladding and structural material. The NRC staff has determined that
this finding is applicable to North Anna because the fuel designs are
consistent with the range of conditions for which analyses of fuel
performance are documented in the NRC staff-approved topical report.
Thus, the performance of M5 material is similar to that of Zircaloy and
ZIRLO fuel cladding, and application of the regulation (i.e., using
Zircaloy or ZIRLO) is not necessary to achieve the underlying purpose
of 10 CFR 50.46.
In its submittal dated March 28, 2002, the licensee stated that
Framatome ANP had conducted oxidation testing to demonstrate that the
Baker-Just equation can be used to conservatively predict the metal-
water reaction rates for M5 fuel cladding, and these test results had
demonstrated that paragraph I.A.5 of 10 CFR part 50, appendix K, was
applicable to M5. The licensee indicated that since these test results
were documented in the NRC staff-approved Topical Report BAW-10227P-A,
an exemption from the requirements of 10 CFR part 50, appendix K, was
not necessary to use M5 fuel cladding. However, based upon the review
of the NRC staff's SER for Topical Report BAW-10227P-A, the NRC staff
has determined that an exemption from the requirements of 10 CFR part
50, appendix K, is necessary in order for the licensee to use M5 fuel
cladding. In section 7.0 of the SER on Topical Report BAW-10227P-A, the
NRC staff concluded that while it is appropriately conservative to
apply the criteria of 10 CFR 50.46 and 10 CFR part 50, appendix K, to
M5 fuel applications, the criteria in the SER are specifically
identified for only Zircaloy fuel cladding material. Furthermore, as
set forth in that SER, the NRC staff found that an exemption from the
requirements of 10 CFR part 50, appendix K, must be obtained in order
to use M5 fuel cladding. In short, as set forth in 10 CFR part 50,
appendix K, I.A.5, the Baker-Just equation, by its terms, applies only
to fuel cladding made of Zircaloy material. As a result, the NRC staff,
upon its own initiative, developed an exemption from the requirements
of 10 CFR part 50, appendix K, for the requested use of M5 fuel
cladding at North Anna, Units 1 and 2.
The underlying purpose of 10 CFR part 50, appendix K, is to ensure
that cladding oxidation and hydrogen generation are appropriately
limited during a LOCA and conservatively accounted for in the ECCS
evaluation model. This regulation sets forth
[[Page 56340]]
requirements for plants that use either Zircaloy or ZIRLO fuel
cladding. Specifically, paragraph I.A.5 of 10 CFR part 50, appendix K,
requires that the Baker-Just equation be used in the ECCS evaluation
model to determine the rate of energy release, hydrogen generation, and
cladding oxidation. This equation conservatively bounds all post-LOCA
scenarios. In the SER that approved Topical Report BAW-10227P, the NRC
staff concluded that the Baker-Just correlation is conservative for
determining high temperature M5 oxidation for LOCA analysis, and that
the correlation is acceptable for LOCA ECCS analysis up to the
currently approved burn-up levels. The NRC staff has determined that
this finding is applicable to North Anna because the fuel designs are
consistent with the range of conditions for which analyses of fuel
performance are documented in the NRC staff-approved topical report.
Therefore, when M5 is used as fuel rod cladding and structural
material, the Baker-Just correlation bounds post-LOCA scenarios, and
ECCS evaluation model criteria will be met. Accordingly, application of
the rule requirements to use Zircaloy or ZIRLO is not necessary to
achieve the underlying purpose of 10 CFR part 50, appendix K.
4.0 Conclusion
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a), the exemption is authorized by law, will not present an undue
risk to the public health and safety, and is consistent with the common
defense and security. Based on the above, the Commission has determined
that pursuant to 10 CFR 50.12(a)(2)(ii), special circumstances are
present. Therefore, the Commission hereby grants the licensee an
exemption from the requirements of 10 CFR 50.44, 10 CFR 50.46, and
appendix K to 10 CFR part 50 for North Anna, Units 1 and 2, with
respect to the use of fuel incorporating M5 material as cladding and
structural material at North Anna, Units 1 and 2.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment (68 FR 55070).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 23rd day of September, 2003.
For the Nuclear Regulatory Commission.
Eric J. Leeds,
Acting Director, Division of Licensing Project Management, Office of
Nuclear Reactor Regulation.
[FR Doc. 03-24669 Filed 9-29-03; 8:45 am]
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