[Federal Register Volume 76, Number 16 (Tuesday, January 25, 2011)]
[Notices]
[Pages 4391-4393]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-1479]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-317 and 50-318; NRC-2011-0004]
Calvert Cliffs Nuclear Power Plant, LLC, Calvert Cliffs Nuclear
Power Plant, Unit Nos. 1 and 2; Exemption
1.0 Background
Calvert Cliffs Nuclear Power Plant, LLC, the licensee, is the
holder of Facility Operating License Nos. DPR-53 and DPR-69 which
authorizes operation of the Calvert Cliffs Nuclear Power Plant, Unit
Nos. 1 and 2 (Calvert Cliffs). The license provides, among other
things, that the facility is subject to all rules, regulations, and
orders of the Nuclear Regulatory Commission (NRC, the Commission) now
or hereafter in effect.
The facility consists of two pressurized-water reactors (PWRs)
located in Calvert County, Maryland.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR) 50.46,
``Acceptance criteria for emergency core cooling systems for light-
water nuclear power reactors,'' requires, among other items, that
``[e]ach boiling or pressurized light-water nuclear power reactor
fueled with uranium oxide pellets within cylindrical zircaloy or ZIRLO
cladding must be provided with an emergency core cooling system (ECCS)
that must be designed so that its calculated cooling performance
following postulated loss-of-coolant accidents [(LOCAs)] conforms to
the criteria set forth in paragraph (b) of this section.'' Appendix K
to 10 CFR part 50, ``ECCS Evaluation Models,'' requires, among other
items, that the rate of energy release, hydrogen generation, and
cladding oxidation from the metal/water reaction shall be calculated
using the Baker-Just equation. The regulations of 10 CFR 50.46 and 10
CFR part 50, Appendix K, make no provisions for use of fuel rods clad
in a material other than zircaloy or ZIRLO.
Calvert Cliffs intends to transition from the Westinghouse Turbo 14
x 14 fuel assembly design to the AREVA Advanced CE-14 HTP fuel assembly
design beginning in 2011 for Unit No. 2 and 2012 for Unit No. 1. The
AREVA fuel design consists of low enriched uranium oxide fuel within M5
zirconium alloy cladding. Since the chemical composition of the M5
alloy differs from the specifications for zircaloy or ZIRLO, a plant-
specific exemption is required to allow the use of the M5 alloy as a
cladding material
[[Page 4392]]
or in other assembly structural components. Therefore, by letter dated
November 23, 2009, the licensee requested an exemption in order to use
M5 advanced alloy for fuel rod cladding and other assembly structural
components at Calvert Cliffs.
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) when special circumstances are present.
Authorized by Law
This exemption results in changes to the operation of the plant by
allowing the use of the M5 alloy as fuel cladding material or for other
assembly structural components in lieu of zircaloy or ZIRLO. As stated
above, 10 CFR 50.12 allows the NRC to grant exemptions from the
requirements of 10 CFR Part 50. The NRC staff has determined that
granting of the licensee's proposed exemption will not result in a
violation of the Atomic Energy Act of 1954, as amended, or the
Commission's regulations. Therefore, the exemption is authorized by
law.
No Undue Risk to Public Health and Safety
The underlying purposes of 10 CFR 50.46 and 10 CFR part 50,
appendix K, are to ensure that facilities have adequate acceptance
criteria for the ECCS, and to ensure that cladding oxidation and
hydrogen generation are appropriately limited during a LOCA and
conservatively accounted for in the ECCS evaluation model,
respectively. Topical Reports (TRs) BAW-10227(P)-A, ``Evaluation of
Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel,''
which was approved by the NRC in February 2000, and BAW-10240(P)-A,
``Incorporation of M5 Properties in Framatome ANP Approved Methods,''
which was approved by the NRC in May 2004, demonstrated that the
effectiveness of the ECCS will not be affected by a change from
zircaloy to M5. In addition, the TRs also demonstrated that the Baker-
Just equation (used in the ECCS evaluation model to determine the rate
of energy release, cladding oxidation, and hydrogen generation) is
conservative in all post-LOCA scenarios with respect to the use of M5
advanced alloy as a fuel rod cladding material or in other assembly
structural components. Based on the above, no new accident precursors
are created by using M5 advanced alloy, thus, the probability of
postulated accidents is not increased. Also, based on the above, the
consequences of postulated accidents are not increased. In addition,
the licensee will use NRC-approved methods for the reload design
process for Calvert Cliffs reloads with M5. Therefore, there is no
undue risk to public health and safety due to using M5.
Consistent With Common Defense and Security
The proposed exemption results in changes to the operation of the
plant by allowing the use of the M5 alloy as fuel cladding material or
in other assembly structural components in lieu of zircaloy or ZIRLO.
This change to the fuel material used in the plant has no relation to
security issues. Therefore, the common defense and security are not
impacted by this exemption request.
Special Circumstances
Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii),
are present whenever application of the regulation in the particular
circumstances would not serve the underlying purpose of the rule or is
not necessary to achieve the underlying purpose of the rule. In this
circumstance neither 10 CFR 50.46 nor 10 CFR part 50, appendix K,
explicitly allows the use of M5 as a fuel rod cladding material or in
use of other assembly structural components.
The underlying purpose of 10 CFR 50.46 is to ensure that facilities
have adequate acceptance criteria for the ECCS. The staff's review and
approval of TR BAW-10227(P)-A addressed all of the important aspects of
M5 with respect to ECCS Performance Requirements: (1) Applicability of
10 CFR 50.46(b) fuel acceptance criteria, (2) M5 material properties
including fuel rod ballooning and rupture strains, and (3) steam
oxidation kinetics and applicability of Baker-Just weight gain
correlation. A subsequent NRC approved TR, BAW-10240(P)-A, further
addressed M5 material properties with respect to LOCA applications.
The underlying purpose of 10 CFR part 50, appendix K, paragraph
I.A.5, is to ensure that cladding oxidation and hydrogen generation are
appropriately limited during a LOCA and conservatively accounted for in
the ECCS evaluation model. Appendix K requires that the Baker-Just
equation be used in the ECCS evaluation model to determine the rate of
energy release, cladding oxidation, and hydrogen generation. In TR BAW-
10227(P)-A, Framatome demonstrated that the Baker-Just model is
conservative in all post-LOCA scenarios with respect to the use of the
M5 advanced alloy as a fuel rod cladding material or in other assembly
structural components, and that the amount of hydrogen generated in an
M5 core during a LOCA will remain within the Calvert Cliffs design
basis.
The M5 alloy is a proprietary zirconium-based alloy comprised of
primarily zirconium (~99 percent) and niobium (~1 percent). The
elimination of tin has resulted in superior corrosion resistance and
reduced irradiation-induced growth relative to both standard zircaloy
(1.7 percent tin) and low-tin zircaloy (1.2 percent tin). The addition
of niobium increases ductility, which is desirable to avoid brittle
failures.
The NRC staff has reviewed the licensee's advanced cladding
material, M5, for PWR fuel mechanical designs as described in TR BAW-
10227(P)-A. In the safety evaluation for TR BAW-10227(P)-A, the staff
concluded that, to the extent specified in the staff's evaluation, the
M5 properties and mechanical design methodology are acceptable for
referencing in fuel reload licensing applications. Therefore, since the
underlying purposes of 10 CFR 50.46 and 10 CFR Part 50, Appendix K,
Paragraph I.A.5 are achieved through the use of the M5 advanced alloy
as a fuel rod cladding material or in other assembly structural
components, the special circumstances required by 10 CFR
50.12(a)(2)(ii) for the granting of an exemption from 10 CFR 50.46 and
10 CFR part 50, Appendix K, exist.
Summary
The NRC staff has reviewed the licensee's request to use the M5
advanced alloy for fuel rod cladding and in other assembly structural
components in lieu of zircaloy or ZIRLO. Based on the NRC staff's
evaluation, as set forth above, the NRC staff concludes that the
exemption is authorized by law, will not present an undue risk to
public health and safety, and is consistent with the common defense and
security. In addition, the NRC staff concludes that the underlying
purposes of 10 CFR 50.46 and 10 CFR Part 50, Appendix K, are achieved
through the use of the M5 advanced alloy. Therefore, pursuant to 10 CFR
50.12(a), the NRC staff concludes that the use of the M5 advanced alloy
for fuel rod cladding and in other assembly structural components is
acceptable and the exemption from 10 CFR 50.46 and 10 CFR Part 50,
Appendix K, is justified.
[[Page 4393]]
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. Also, special circumstances are present.
Therefore, the Commission hereby grants the licensee an exemption from
the requirements of 10 CFR 50.46 and 10 CFR part 50, appendix K, for
Calvert Cliffs.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant impact on the
quality of the human environment (76 FR 1469); published on January 10,
2011.
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 13th day of January 2011.
For the Nuclear Regulatory Commission.
Joseph G. Giitter,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. 2011-1479 Filed 1-24-11; 8:45 am]
BILLING CODE 7590-01-P