[Federal Register Volume 77, Number 175 (Monday, September 10, 2012)]
[Notices]
[Pages 55509-55510]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-22173]


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NUCLEAR REGULATORY COMMISSION

[NRC-2012-0199; Docket No. 50-316]


Indiana Michigan Power Company; Donald C. Cook Nuclear Plant, 
Unit 2; Exemption

1.0 Background

    Indian Michigan Power Company (the licensee) is the holder of 
Renewed Facility Operating License No. DPR-74, which authorizes 
operation of the Donald C. Cook Nuclear Plant, Unit 2 (CNP-2). The 
license provides, among other things, that the facility is subject to 
all rules, regulations, and orders of the U.S Nuclear Regulatory 
Commission (NRC, or 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), 
Section 50.12, ``Specific exemptions,'' the licensee has, by letter 
dated September 29, 2011 (Agencywide Documents Access and Management 
System (ADAMS) Accession No. ML11286A198), 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 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 ZIRLOTM 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 ZIRLOTM. 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 ZIRLOTM fuel rod cladding. 
Thus, an exemption from the requirements of 10 CFR 50.46 and 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 ZIRLOTM fuel rod cladding at CNP-2.

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 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-2. 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.

[[Page 55510]]

No Undue Risk to Public Health and Safety

    The underlying purpose of 10 CFR 50.46 is to establish acceptance 
criteria for adequate ECCS performance. As previously documented in the 
NRC staff's review of topical reports submitted by Westinghouse 
Electric Company, LLC (Westinghouse), and subject to compliance with 
the specific conditions of approval established therein, the NRC staff 
finds that the applicability of these ECCS acceptance criteria to 
Optimized ZIRLOTM has been demonstrated by Westinghouse. 
Ring compression tests performed by Westinghouse on Optimized 
ZIRLOTM pproved topical report WCAP-12610-P-A & CENPD-404-P-
A, Addendum 1-A, ``Optimized ZIRLOTM,'' July 2006, ADAMS 
Accession No. ML062080576; the public version is WCAP-14342-A & CENPD-
404-NP-A at ADAMS Accession No. ML062080569) demonstrate an acceptable 
retention of post-quench ductility up to 10 CFR 50.46 limits of 2,200 
[deg]F and 17 percent equivalent clad reacted (ECR). Furthermore, the 
NRC staff has concluded that oxidation measurements previously provided 
by Westinghouse (``SER Compliance with WCAP-12610-P-A & CENPD-404-P-A 
Addendum 1-A `Optimized ZIRLOTM,''' November 2007, non-
public version at ADAMS Accession No. ML073130562, public version at 
ADAMS Accession No. ML073130560) illustrate that oxide thickness (and 
associated hydrogen pickup) for Optimized ZIRLOTM at any 
given burnup would be less than both zircaloy-4 and ZIRLOTM. 
Hence, the NRC staff concludes that Optimized ZIRLOTM would 
be expected to maintain better post-quench ductility than 
ZIRLOTM. This finding is further supported by an ongoing 
loss-of-coolant accident (LOCA) research program at Argonne National 
Laboratory, which has identified a strong correlation between cladding 
hydrogen content (due to in-service corrosion) and post-quench 
ductility.
    In addition, the provisions of 10 CFR 50.46 require the licensee to 
periodically evaluate the performance of the emergency core cooling 
system (ECCS), using currently approved LOCA models and methods, to 
ensure that the fuel rods will continue to satisfy 10 CFR 50.46 
acceptance criteria. Granting the exemption to allow the licensee to 
use Optimized ZIRLO\TM\ fuel rods in addition to the current mix of 
fuel rods does not diminish this requirement of periodic evaluation of 
ECCS performance. Thus, the underlying purpose of the rule will 
continue to be achieved for Donald C. Cook Nuclear Plant, Unit 2.
    Paragraph I.A.5 of Appendix K to 10 CFR part 50 states that the 
rates of energy release, 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 this provision of the rule would not 
permit use of the equation for Optimized ZIRLO\TM\ cladding for 
determining acceptable fuel performance. However, the NRC staff 
previously found that metal-water reaction tests performed by 
Westinghouse on Optimized ZIRLO\TM\ (see Appendix B of WCAP-12610-P-A & 
CENPD-404-P-A, Addendum 1-A) demonstrate conservative reaction rates 
relative to the Baker-Just equation. Thus, the NRC staff agrees that 
application of Appendix K, paragraph I.A.5 is not necessary to achieve 
the underlying purpose of the rule in these circumstances. Since these 
evaluations demonstrate that the underlying purpose of the rule will be 
met, there will be no undue risk to the public health and safety.

Consistent With Common Defense and Security

    The proposed exemption would allow the use of Optimized ZIRLO\TM\ 
fuel rod cladding material at CNP-2. 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-
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 and has published an environmental 
assessment for this exemption on August 23, 2012 (77 FR 51071).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 23rd day of August, 2012.

    For the Nuclear Regulatory Commission.
Michele Evans,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. 2012-22173 Filed 9-7-12; 8:45 am]
BILLING CODE 7590-01-P