ML052700197

Relief Request - Reactor Vessel Closure Head Penetration Flaw Characterization Relief Request MR 02-018-2, Revision 2

ML052700197
Person / Time
Site:	Point Beach
Issue date:	01/18/2006
From:	Kobetz T Plant Licensing Branch III-2
To:	Koehl D Nuclear Management Co
Muniz A, NRR/DLPM, 415-4093
References
TAC MC7482
Download: ML052700197 (6)

Text

January 18, 2006 Mr. Dennis L. Koehl Site Vice President Point Beach Nuclear Plant Nuclear Management Company, LLC 6590 Nuclear Road Two Rivers, WI 54241-9516

SUBJECT:

POINT BEACH NUCLEAR PLANT, UNIT 1 - REACTOR VESSEL CLOSURE HEAD PENETRATION FLAW CHARACTERIZATION RELIEF REQUEST MR 02-018-2, REVISION 2 (TAC NO. MC7482)

Dear Mr. Koehl:

By letter to the Nuclear Regulatory Commission (NRC) dated July 1, 2005, the Nuclear Management Company, LLC (NMC), submitted Relief Request MR 02-018-2, Revision 2 for Point Beach Nuclear Plant (PBNP), Unit 1. The relief request pertains to relief from the requirement to characterize flaws that may exist in the remnants of the control rod drive mechanism nozzle J-groove welds after the repair of a reactor vessel head penetration.

Relief Request MR 02-018-2 was originally authorized on September 10, 2003. In its safety evaluation (SE) of the initial relief request, the NRC staff limited its authorization to cases where there was no overlap of the new Alloy 52 weld material onto any portion of the remnant J-groove weld. MR 02-018-2, Revision 1, submitted on May 13, 2004, intended by NMC to provide the technical basis for eliminating this restriction, was authorized by the NRC staff on July 16, 2004. By letter dated July 1, 2005, NMC submitted Revision 2 to Relief Request MR-02-018-2, specifically to correct an error in the reactor pressure vessel (RPV) upper head temperature for PBNP, Unit 1.

The NRC staff has completed its review of Relief Request MR-02-018-2, Revision 2 as documented in the enclosed SE. Our SE concluded that your proposed alternative provides an acceptable level of quality and safety. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the remainder of the operating cycle #29 at PBNP, Unit 1, which ended on November 24, 2005. All other American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

D. Koehl If you have any questions concerning this matter, please contact Mr. F. Lyon of my staff at (301) 415-2296.

Sincerely,

/RA/

Timothy Kobetz, Acting Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-266

Enclosure:

As stated cc w/encl: See next page

D. Koehl If you have any questions concerning this matter, please contact Mr. F. Lyon of my staff at (301) 415-2296.

Sincerely, Timothy Kobetz, Acting Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-266

Enclosure:

As stated cc w/encl: See next page DISTRIBUTION:

PUBLIC RidsOgcRp TSteingass LPLIII-1 R/F RidsAcrsAcnwMailCenter RidsNrrDciCpnb RidsNrrDorlLplE RidsNrrPMFLyon RidsRgn3MailCenter RidsNrrLADClarke DORL DPR AMuniz DWeaver ADAMS Accession Number: ML052700197

• memo date 8/12/05

• • previously concurred NRR-028 OFFICE LPLIII-1/PE LPLIII-1/PM LPLIII-1/LA CPNB/BC OGC LPLIII-1/BC (A)

NAME AMuniz CLyon DClarke** TChan* JZorn** TKobetz DATE 1/13/06 1/17/06 12/29/05 8/12/05 1/5/06 1/18/06 OFFICIAL RECORD COPY

Point Beach Nuclear Plant, Unit 1 cc:

Jonathan Rogoff, Esquire Mr. Jeffery Kitsembel Vice President, Counsel & Secretary Electric Division Nuclear Management Company, LLC Public Service Commission of Wisconsin 700 First Street P.O. Box 7854 Hudson, WI 54016 Madison, WI 53707-7854 Mr. F. D. Kuester Nuclear Asset Manager President & Chief Executive Officer Wisconsin Electric Power Company WE Generation 231 West Michigan Street 231 West Michigan Street Milwaukee, WI 53201 Milwaukee, WI 53201 Michael B. Sellman Regulatory Affairs Manager President and Chief Executive Officer Point Beach Nuclear Plant Nuclear Management Company, LLC Nuclear Management Company, LLC 700 First Street 6610 Nuclear Road Hudson, MI 54016 Two Rivers, WI 54241 Douglas E. Cooper Mr. Ken Duveneck Senior Vice President - Group Operations Town Chairman Palisades Nuclear Plant Town of Two Creeks Nuclear Management Company, LLC 13017 State Highway 42 27780 Blue Star Memorial Highway Mishicot, WI 54228 Covert, MI 49043 Chairman Site Director of Operations Public Service Commission Nuclear Management Company, LLC of Wisconsin 6610 Nuclear Road P.O. Box 7854 Two Rivers, WI 54241 Madison, WI 53707-7854 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532-4351 Resident Inspector's Office U.S. Nuclear Regulatory Commission 6612 Nuclear Road Two Rivers, WI 54241

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST MR 02-018-2, REVISION 2 POINT BEACH NUCLEAR STATION, UNIT 1 NUCLEAR MANAGEMENT COMPANY, LLC DOCKET NO. 50-266

1.0 INTRODUCTION

By letter to the Nuclear Regulatory Commission (NRC, Commission) dated July 1, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML051940343), Nuclear Management Company, LLC (NMC, the licensee), submitted Relief Request MR-02-018-2, Revision 2, to correct an error in the reactor pressure vessel (RPV) upper head operating temperature for Point Beach Nuclear Plant (PBNP), Unit 1. Relief Request MR 02-018-2 was originally authorized on September 10, 2003 (ADAMS Accession No. ML032310402). In its safety evaluation (SE) of the initial relief request, the NRC staff limited its authorization to cases where there was no overlap of the new Alloy 52 weld material onto any portion of the remnant J-groove weld. MR 02-018-2, Revision 1, submitted on May 13, 2004 (ADAMS Accession No. ML041410464), intended by NMC to provide the technical basis for eliminating this restriction, was authorized by the NRC staff on July 16, 2004 (ADAMS Accession No. ML041760065). By letter dated July 1, 2005, NMC submitted Revision 2 to its Relief Request MR-02-018-2, specifically to correct an error in the RPV upper head temperature for PBNP, Unit 1. Therefore, this SE will address only the effects of the increase in RPV head operating temperature on the NRC SE dated July 16, 2004.

2.0 REGULATORY EVALUATION

Alternatives to requirements may be authorized or relief granted by the NRC pursuant to Title 10 of Code of Federal Regulations (10 CFR) 50.55a(a)(3)(i), 10 CFR 50.55a(a)(3)(ii), or 10 CFR 50.55a(g)(6)(i). In proposing alternatives or requesting relief, the licensee must demonstrate that: (1) the proposed alternatives provide an acceptable level of safety; or (2) compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety; or (3) conformance is impractical for the facility. Pursuant to 10 CFR 50.55a(g)(4)(iv), inservice inspection of items may meet the requirements set forth in subsequent editions and addenda of the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code (Code) that are incorporated by reference in 10 CFR 50.55a(b), subject to the limitations and modifications listed therein, and subject to Commission approval. Portions of editions or addenda may be used provided that all related requirements of the respective editions or addenda are met. In its letter dated July 1, 2005, pursuant to 10 CFR 50.55a(a)(3)(i), the licensee requested a revision to the relief authorized by the NRC staffs SE dated July 16, 2004, from the requirements of the 1998 Edition of the ASME Code,Section XI, IWA-3300(b), IWB-3142.4, and IWB-3420, which require characterization of flaw(s) existing in the remnant of the J-groove weld(s) that will remain in service for PBNP, Unit 1,

reactor vessel closure heads if a control rod drive mechanism nozzle must be partially removed and a new pressure boundary deposited over a portion of the J-groove weld remnant.

3.0 TECHNICAL EVALUATION

The NRC staff notes the revised calculations submitted by the licensee show a slightly higher crack growth rate due to the higher operating temperature, resulting in a change to the calculated operating time from 1.39 effective full power years (EFPY) to 1.31 EFPY. This equates to a change from 16.68 months to 15.72 months for a net result of 0.96 month shorter duration of time until a hypothetical flaw reaches the toe of the J-groove weld in the weld overlap region. The conservative assumptions in the revised calculations indicate that an actual flaw would require more than 1.31 EFPY to grow through the J-groove weld. PBNP, Unit 1 is not expected to accumulate greater than 1.41 EFPY prior to the plant shutdown due to operational constraints. The delta in RPV operating temperatures is sufficiently low to not challenge the conservative assumptions in the calculations that formed part of the basis for NRC authorization of the current and previous revisions of this relief request. The NRC staff concludes that the previously granted reliefs remain in effect for this repair situation.

4.0 CONCLUSION

The NRC staff concludes that Relief Request MR-02-018-2, Revision 2 is acceptable because the proposed alternative authorized in the previous revisions has not changed, the delta in RPV operating temperatures is sufficiently low to not challenge the conservative assumptions in the calculations made to support continued safe operation, and the removal from service of the RPV head during the Autumn 2005 outage. Based on the information provided in the licensee's submittal, the NRC staff concludes that the alternative proposed in MR-02-018-2, Revision 2 provides an acceptable level of quality and safety. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the remainder of operating cycle

1. 29 at PBNP, Unit 1, which ended on November 24, 2005.

All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

Principal Contributor: T. Steingass Date: January 19, 2006