ML061650201

Supplement to 10 CFR 50.46 & 10 CFR 50 Appendix K Exemption Request

ML061650201
Person / Time
Site:	Palisades
Issue date:	06/14/2006
From:	Harden P Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MC8576
Download: ML061650201 (2)

Text

Palisades Nuclear Plant Operated by Nuclear Management Company, LLC June 14,2006 10 CFR 50.12 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Power Plant Dockets 50-255 License No. DPR-20 Supplement to 10 CFR 50.46 and 10 CFR 50 Appendix K Exemption Request (TAC MC8576)

By letter dated October 4,2005, Nuclear Management Company, LLC (NMC) requested latory Commission (NRC) review and approval of a proposed exemption ant to 10 CFR 50.12, for the Palisades Nuclear Plant (PNP). NMC t a plant specific exemption was required to support the use of M5 fuel cladding at PNP.

On March 22, 2006, a meeting was held with the NRC Staff to discuss implementing M5 fuel cladding at PNP. The proposed exemption request to support use of M5 fuel cladding was discussed. It was determined at the meeting that supplemental information was needed on the proposed exemption request. Enclosure 1 contains the supplemental information.

Summarv of Commitments This letter contains no new commitments and no revisions to existing commitments.

Paul A. Harden Site Vice President, Palisades Nuclear Plant Nuclear Management Company, LLC Enclosure (1)

CC: Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC 27780 Blue Star Memorial Highway Covert, Michigan 49043-9530 Telephone: 269.764.2000

ENCLOSURE 1 SUPPLEMENT TO EXEMPTION REQUEST PALISADES NUCLEAR PLANT The applicability of the criteria in 10 CFR 50.46 to M5 cladding is addressed in Section 4.2.1, and Appendix G, of the topical report BAW-10227PA, "Evaluation of Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel," Revision 1.

The regulation 10 CFR 50.46 requires that loss-of-coolant accident (LOCA) calculations demonstrate that the fuel design and plant systems meet five criteria. Two of these criteria, the limit on cladding temperature and local oxidation, are potentially dependent on the specific characteristics of a given alloy. To justify that these two criteria are applicable to M5 cladding, a set of accident simulation tests were conducted comparing the performance of M5 cladding to Ziracloy-4 cladding.

The purpose of the individual criteria is:

1. Peak Cladding Temperature < 2200" F Limits cladding embrittlement and maintains margin to zirconium/water autocatalytic reaction.

2. Local ~ l &.,.i n g Oxidation < 17 %

Limits cladding embrittlement.

The experiments included cladding oxidation kinetics tests (potential for autocatalytic effect) and cladding embrittlement tests using cold water quench. The tests demonstrated comparable accident survival capability between Zircaloy-4 and M5. At the specified criteria, neither cladding approached an autocatalytic reaction rate, nor was either cladding shown to be susceptible to clad shattering (embrittlement effect).

Both retained similar and substantial margins to undesirable results. The NRC safety evaluation for the topical report BAW-10227PA states, "These FCF tests confirm that the 2200 OF PCT and 17 percent oxidation criteria are conservative for M5 cladding in order to prevent cladding embrittlement and fragmentation during a LOCA."

The applicability of the Baker Just oxidation correlation specified in 10 CFR 50, Appendix K, for Zircaloy cladding to M5 cladding is shown in Appendix D of the topical report BAW-10227PA. The series of experiments which were performed demonstrated that the high temperature oxidation of M5 is conservatively represented by the Baker Just oxidation correlation.

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