Indiana Michigan Power Company; Donald C. Cook Nuclear Plant, Unit 1; Exemption, 55422-55423 [2011-22806]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 76, Number 173 (Wednesday, September 7, 2011)]
[Notices]
[Pages 55422-55423]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-22806]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-315; NRC-2011-0188]


Indiana Michigan Power Company; Donald C. Cook Nuclear Plant, 
Unit 1; Exemption

1.0 Background

    Indiana Michigan Power Company (the licensee) is the holder of 
Facility Operating License No. DPR-58, which authorizes operation of 
the Donald C. Cook Nuclear Plant, Unit 1 (CNP-1). 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 a pressurized-water reactor located in 
Berrien County in Michigan.

2.0 Request/Action

    Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 
50.12, ``Specific exemptions,'' the licensee has, by letter dated 
December 16, 2010 (Agencywide Documents Access and Management System 
(ADAMS) Accession No. ML103630358), requested an exemption from 10 CFR 
50.46, ``Acceptance criteria for emergency core cooling systems for 
light-water nuclear power reactors,'' and Appendix K to 10 CFR part 50, 
``ECCS Evaluation Models.'' The regulations in 10 CFR 50.46 contain 
acceptance criteria for the emergency core cooling system (ECCS) for 
reactors fueled with zircaloy or ZIRLO\TM\ cladding. In addition, 
Appendix K to 10 CFR part 50 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. The Baker-Just 
equation assumes the use of a zirconium alloy, which is a material 
different from Optimized ZIRLO\TM\. The licensee's requested exemption 
relates solely to the specific types of cladding material specified in 
these regulations. As written, the regulations presume the use of 
zircaloy or ZIRLO\TM\ fuel rod cladding. Thus, an exemption from the 
requirements of 10 CFR 50.46 and

[[Page 55423]]

Appendix K is needed to support the use of a different fuel rod 
cladding material. Accordingly, the licensee requested an exemption 
that would allow the use of Optimized ZIRLO\TM\ fuel rod cladding at 
CNP-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 (1) when 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 10 CFR 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 use of Optimized ZIRLO\TM\ fuel rod 
cladding material at CNP-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 purpose of 10 CFR 50.46 is to establish acceptance 
criteria for ECCS performance. Westinghouse topical reports WCAP-12610-
P-A and CENPD-404-P-A, Addendum 1-A, ``Optimized ZIRLO\TM\,'' dated 
July 2006, contain the justification to use Optimized ZIRLO\TM\ fuel 
rod cladding material in addition to Zircaloy-4 and ZIRLO\TM\ (these 
topical reports are non-publicly available because they contain 
proprietary information). The NRC staff approved the use of these 
topical reports, subject to the conditions stated in the NRC staff's 
safety evaluation for each topical report. Ring compression tests 
performed by Westinghouse on Optimized ZIRLO\TM\ were reviewed and 
approved by the NRC staff (ADAMS Accession No. ML062080569), and 
demonstrate an acceptable retention of post-quench ductility up to the 
10 CFR 50.46 limits of 2200 degrees Fahrenheit and 17 percent 
equivalent clad reacted. Furthermore, the NRC staff has concluded that 
oxidation measurements provided by the licensee (ADAMS Accession No. 
ML073130560) illustrate that oxide thickness (and associated hydrogen 
pickup) for Optimized ZIRLO\TM\ at any given burnup would be less than 
that for both zircaloy and ZIRLO\TM\. Hence, the NRC staff concludes 
that Optimized ZIRLO\TM\ would be expected to maintain improved post-
quench ductility over ZIRLO\TM\. Finally, the licensee stated that 
Westinghouse will perform an evaluation to ensure that the Optimized 
ZIRLO\TM\ fuel rods continue to satisfy 10 CFR 50.46 acceptance 
criteria utilizing currently NRC-approved loss-of-coolant accident 
(LOCA) models and methods.
    The underlying purpose of 10 CFR part 50, Appendix K, Section 
I.A.5, ``Metal-Water Reaction Rate,'' 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 of 10 CFR Part 50 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. Since the use of 
the Baker-Just equation presumes the use of zircaloy-clad fuel, strict 
application of the rule would not permit use of the equation for 
Optimized ZIRLO\TM\ cladding for determining acceptable fuel 
performance. Westinghouse has demonstrated that the Baker-Just model is 
conservative in all post-LOCA scenarios with respect to the use of the 
Optimized ZIRLO\TM\ advanced alloy as a fuel cladding material.
    The NRC-approved topical reports have demonstrated that predicted 
chemical, thermal, and mechanical characteristics of the Optimized 
ZIRLO\TM\ alloy cladding are bounded by those approved for ZIRLO\TM\ 
under anticipated operational occurrences and postulated accidents. 
Reload cores are required to be operated in accordance with the 
operating limits specified in the technical specifications and the core 
operating limits report.
    Based on the above, no new accident precursors are created by using 
Optimized ZIRLO\TM\, 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 to 
public health and safety due to using Optimized ZIRLO\TM\.

Consistent With Common Defense and Security

    The proposed exemption would allow the use of Optimized ZIRLO\TM\ 
fuel rod cladding material at CNP-1. This change to the plant 
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 
wording of the regulations in 10 CFR 50.46 and Appendix K is not 
directly applicable to Optimized ZIRLO\TM\, even though the evaluations 
above show that the intent of the regulation is met. Therefore, since 
the underlying purposes of 10 CFR 50.46 and Appendix K are achieved 
through the use of Optimized ZIRLO\TM\ fuel rod cladding material, the 
special circumstances required by 10 CFR 50.12(a)(2)(ii) for the 
granting of an exemption exist.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12, 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 Appendix K to 10 CFR Part 50, to 
allow the use of Optimized ZIRLO\TM\ fuel rod cladding material at CNP-
1.
    Pursuant to 10 CFR 51.32, the Commission published an environmental 
assessment for this exemption on August 22, 2011 (76 FR 52356).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 24th day of August 2011.

    For the Nuclear Regulatory Commission.
Louise Lund,
Acting Director, Division of Operating Reactor Licensing, Office of 
Nuclear Reactor Regulation.
[FR Doc. 2011-22806 Filed 9-6-11; 8:45 am]
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