[Federal Register Volume 72, Number 246 (Wednesday, December 26, 2007)]
[Notices]
[Pages 73045-73047]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-24975]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-317]
Calvert Cliffs Nuclear Power Plant, Inc.; Calvert Cliffs Nuclear
Power Plant, Unit No. 1; Exemption
1.0 Background
Calvert Cliffs Nuclear Power Plant, Inc. (the licensee), is the
holder of Renewed Facility Operating License Nos. DPR-53 and DPR-69,
which authorize operation of the Calvert Cliffs Nuclear Power Plant,
Unit Nos. 1 and 2 (Calvert Cliffs 1 and 2), respectively. 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 located in
Calvert County, Maryland.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR), Part 50,
Section 50.46, ``Acceptance criteria for emergency core cooling systems
for light-water nuclear power reactors,'' requires, in part, that
``Each boiling or pressurized light-water nuclear power reactor fueled
with uranium oxide pellets within cylindrical zircaloy or ZIRLO \TM\
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,
``ECCS Evaluation Models,'' to 10 CFR Part 50 requires, in part, 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 Baker-Just equation assumes that the cladding material is
composed of either zircaloy or ZIRLO \TM\.
By letter dated February 23, 2007, the licensee requested an
exemption from the requirements of 10 CFR 50.46 and Appendix K to 10
CFR Part 50 to allow the use of lead fuel assemblies (LFAs) clad with
advanced zirconium-based alloys manufactured by Westinghouse Electric
Company and M5 \TM\ alloy manufactured by AREVA. The advanced
zirconium-based and M5 \TM\ alloys are proprietary alloys and are
chemically different from either zircaloy or ZIRLO \TM\ fuel cladding
materials, which are approved for use. Therefore, a plant-specific
exemption from these regulations is required to support the use of LFAs
that are not manufactured with zircaloy or ZIRLO \TM\.
Previously, by letter dated April 11, 2003, the NRC staff approved
the irradiation of 8 LFAs, four Westinghouse LFAs and four AREVA LFAs,
for 2 operating cycles in the core of Calvert Cliffs 2. These LFAs were
inserted into the Unit 2 core in April of 2003 and remained there
during Operating Cycles 15 and 16. Subsequently, by letter dated
November 9, 2006, the NRC staff approved the irradiation of 4 LFAs, two
Westinghouse LFAs and two AREVA LFAs, for a third operating cycle in
either Calvert Cliffs 1 or Calvert Cliffs 2. The licensee subsequently
inserted these 4 LFAs into the core of Calvert Cliffs 2 during their
spring 2007 refueling outage for operating cycle 17 which is currently
ongoing. The remaining 4 LFAs, two Westinghouse LFAs and two AREVA
LFAs, were discharged to the spent fuel pool for detailed post-
irradiation examinations during the spring 2007 Unit 2 refueling
outage.
In the licensee's letter of February 23, 2007, the licensee
requested the exemption to support the re-insertion of the remaining 4
LFAs, two
[[Page 73046]]
Westinghouse LFAs and two AREVA LFAs, for a third operating cycle.
These LFAs would be placed in high-duty core locations in Calvert
Cliffs 1 for operating cycle 19 in order to gain high burnup
experience. The licensee requested to irradiate the LFAs beyond the
current burnup limit to a peak rod average of 70,000 MWD/MTU for
Calvert Cliffs Unit 1.
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. Under Section 50.12(a)(2),
special circumstances include, among other things, when application of
the specific regulation in the particular circumstance would not serve,
or is not necessary to achieve, the underlying purpose of the rule.
Authorized by Law
This exemption would allow the licensee to re-insert up to four
LFAs, two Westinghouse LFAs and two AREVA LFAs, which contain some fuel
rods clad with advanced zirconium-based and M5 \TM\ alloys that do not
meet the definition of Zircaloy or ZIRLO \TM\ as specified by 10 CFR
50.46, into the core of Calvert Cliffs 1. 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 is to establish acceptance
criteria for ECCS performance. Previously, the Westinghouse safety
evaluation (WCAP-15874-NP, Revision 0, ``Safety Analysis Report for Use
of Improved Zirconium-based Cladding Materials in Calvert Cliffs Unit 2
Batch T Lead Fuel Assemblies,'' dated April 2002) and approved
Framatome ANP Topical Report (BAW-10227P-A, ``Evaluation of Advanced
Cladding and Structural Material (M5) in PWR Reactor Fuel,'' Framatome
Cogema Fuels, February 2000) demonstrated the acceptability of the
advanced zirconium-based and M5 \TM\ cladding under LOCA conditions.
The unique features of the LFAs were evaluated for effects on the LOCA
analysis. The results showed that the LFAs would not adversely affect
the ECCS performance. Since the four LFAs will be located at high-duty
other than LOCA-limiting core locations, the licensee concludes that
the LOCA safety analyses will remain bounding for these LFAs for
Calvert Cliffs 1.
Paragraph I.A.5 of Appendix K to 10 CFR Part 50 states that the
rates of energy, hydrogen concentration, and cladding oxidation from
the metal-water reaction shall be calculated using the Baker-Just
equation. Since the Baker-Just equation presumes the use of zircaloy
clad fuel, strict application of the rule would not permit use of the
equation for the advanced zirconium-based and M5 \TM\ alloys for
determining acceptable fuel performance. The underlying intent of this
portion of the Appendix is to ensure that analysis of fuel response to
LOCAs is conservatively calculated. The Westinghouse safety evaluation
and approved AREVA topical report show that, due to the similarities in
the chemical composition of the advanced zirconium-based and M5 \TM\
alloys and zircaloy, the application of the Baker-Just equation in the
analysis of the advanced zirconium-based and M5 \TM\ clad fuel rods
will continue to conservatively bound all post-LOCA scenarios. Thus,
the application of Appendix K, Paragraph I.A.5 is not necessary to
achieve its underlying purpose in these circumstances.
Based on the acceptable performance of 8 LFAs in the Calvert Cliffs
2 reactor core during operating cycles 15 and 16, the staff concludes
that the licensee has demonstrated that the four LFAs will perform
adequately under LOCA conditions, and thus the LFAs are acceptable for
operation for Calvert Cliffs 1 operating cycle 19. Based on the above,
the staff concludes that it is acceptable to grant an exemption from
the requirements of 10 CFR 50.46, and Appendix K to 10 CFR Part 50 for
Calvert Cliffs 1.
Based on the above, no new accident precursors are created by the
exemption to allow use of advanced zirconium-based and M5 \TM\ alloy
clad fuel, thus, the probability of postulated accidents is not
increased. Also, based on the above, the consequences of postulated
accidents are not increased. Therefore, there is no undue risk [since
risk is probability x consequences] to public health and safety.
Consistent With Common Defense and Security
The proposed exemption would allow the use of LFAs with advanced
cladding materials. This change to the plant core configuration has no
relation to security issues. Therefore, the common defense and security
is not impacted by this exemption.
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 is not necessary to achieve the underlying purpose of the
rule. The underlying purpose of 10 CFR 50.46 and Appendix K to 10 CFR
Part 50 is to establish acceptance criteria for ECCS performance. The
licensee stated that the wording of the regulations renders the
criteria of 10 CFR 50.46 and Appendix K inapplicable to the advanced
zirconium-based and M5 \TM\ alloy clad fuel, even though the approved
Westinghouse safety evaluation and AREVA topical report shows that the
intent of the regulations are met. Therefore, since the underlying
purpose of 10 CFR 50.46 and Appendix K to 10 CFR Part 50 is achieved
with the use of the advanced zirconium-based and M5 \TM\ alloy clad
fuel, the special circumstances required by 10 CFR 50.12(a)(2)(ii) for
granting of an exemption from 10 CFR 50.46 and Appendix K exist.
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 with
respect to the use of LFAs with advanced zirconium-based and M5 \TM\
alloy clad fuel.
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 (72 FR 71449).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 17th day of December 2007.
[[Page 73047]]
For the Nuclear Regulatory Commission.
Catherine Haney,
Director, Division of Operating Reactor Licensing, Office of Nuclear
Reactor Regulation.
[FR Doc. E7-24975 Filed 12-21-07; 8:45 am]
BILLING CODE 7590-01-P