ML20207G217

Forwards SE Accepting Proposed Mod to Each of Four Core Shroud Stabilizers for Implementation During Current 1999 Refueling Outage for Plant,Unit 1

ML20207G217
Person / Time
Site:	Nine Mile Point
Issue date:	06/07/1999
From:	Bajwa S NRC (Affiliation Not Assigned)
To:	Mueller J NIAGARA MOHAWK POWER CORP.
Shared Package
ML20207G222	List: ML20207G217 ML20207G226
References
TAC-MA5433, NUDOCS 9906110065
Download: ML20207G217 (4)

Text

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666 0001

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Q*****l June 7,1999 Mr. John H. Mueller Chief NuclearOfficer Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Operations Building, Second Floor P.O. Box 63 Lycoming, NY 13093

SUBJECT:

ALTERNATIVE REPAIR OF THE CORE SHROUD TIE ROD UPPER SPRING ASSEMBLY, NINE MILE POINT NUCLEAR STATION, UNIT NO.1 (TAC NO. MAS 433)

Dear Mr. Mueller:

By letter dated May 21,1999, as supplemented by letter dated May 28,1999, and a telephone call (see summary of telephone conversation dated June 3,1999), Niagara Mohawk Power Corporation (NMPC and licensee) proposed a modification to each of the four core shroud tie rod assemblies for implementation during the current 1999 refueling outage for Nine Mile Point Nuclear Station, Unit 1 (NMP1). The modification results from the visual examination of the core shroud tie rods during the current outage, which revealed that a 3/8-inch cap screw from the upper spring assembly had failed. The proposed modification would replace the design function of the failed cap screw connecting the upper spring bracket to the upper spring, and other cap screws that have the potential for future failure. The repair modification is consistent with, and meets the guidelines of the Boiling Water Reactor Vessel and Internals Project's document BWRVIP-02, " Core Shroud Repair Design Criteria," as approved by the NRC staff in a safety evaluation (SE) dated September 29,1994. Because the proposed core shroud repair is not included under the definition for repair or replacement specified in Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),

NMPC requested that the NRC staff approve the proposed repair as an alternative repair pursuant to Title 10 of Code of Federal Reoulations (10 CFR) Section 50.55a(a)(3)(i). s Pursuant to 10 CFR 50.55a(g)(4), components (including supports) that are classified as ASME Code Class 1, Class 2, and Class 3 must meet the requirements of Section XI of the ASME Code. The proposed repair has been designed as an alternative to the requirements of Section XI of the ASME Code. The NRC staff has reviewed the proposed alternative repair. The  !

enclosure is our SE which concludes that the strJctural design of the repair modification satisfies the structural requirements of the ASME Code, Section Ill, Subsection NG," Core ,J Support Structures," and is, therefore, acceptable. The NRC staff finds in the SE that the I materials selected for component repair are specified as approved materials by the ASME Code and are, therefore, acceptable. Acceptable provisions are provided to preclude the occurrence of loose parts. Accordingly, the NRC staff concludes that the proposed modification g provides an acceptable level of quality and safety, and it is authorized in accordance 10 CFR / Oj 50.55a(a)(3)(i).

9906110065 990607 PDR ADOCK 05000220 P PDR

Mu;ll:r June 7,1999 If you have any questions regarding this matter, please contact Darl Hood by phone on i 301-415-3049 or by electronic mail at dsh@nrc. gov.

Sincerely,

. ORIGINAL SIGNED BY S. BLACK FOR:

S. Singh Bajwa, Chief, Section 1 Project Directorate l l Division of Licensing Project Management l Office of Nuclear Reactor Regulation Docket No. 50-220 l

Enclosure:

Safety Evaluation 1

i cc w/ encl: See next page l

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DISTRIBUTION:

Docket File J. Rajan M. Oprendek, RGN-l PUBLIC W. Koo E. Imbro PDI-1 R/F R. Scholl (e-mail SE only) K. Manoly S. Little OGC W. Bateman D. Hood ACRS R. Hermann l

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10019 DOCUMENT NAME: G:\PD1-1\NMP1\ RELA 5433.WPD To rccoive a copy of this document. indicate in the box: "C" - Copy without attachment / enclosure "E" - Copy with attachment / enclosure "N" - No cooy 0FFICE PDl-1/PM _ _ l PDI-1/LA 3) lG: PDI-1/SC , ,, ld .0GC _ A A /l,() l NAME DHood:Icc W7 SLittle # {4 ' V SBajwa M L (M

N DATE 06/ry/99 l06/1 /39 '\ 06/ 7 /99 06/ 7 /99 OFFICIAL RECORD COPY

J. Mueller '

If you have any questions regarding this matter, please contact Darl Hood by phone on 301-415-3049 or by electronic mail at dsh@nrc. gov.

Sincerely, A

S. Singh ajwa, Chief, Sectio 1 Project Directorate i Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-220

Enclosure:

Safety Evaluation  ;

I cc w/ encl: See next page  !

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l Nine Mile Point Nuclear Station Unit No.1 Regional Administrator, Region I i U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident inspector l U.S. Nuclear Regulatory Commission l

P.O. Box 126 Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attomey General New York Department of Law

, 120 Broadway New York, NY 10271 Mr. Paul D. Eddy l State of New York Department of Public Service Power Division, System Operations  !

3 Empire State Plaza '

Albany, NY 12223 Mr. F. William Valentino, President New York State Energy, Research, and Development Authority Corporate Plaza West 286 Washington Avenue Extension Albany, NY 12203-6399 Mark J. Wetterhahn, Esquire Winston & Strawn 1400 L Street, NW i Washington, DC 20005-3502 I l

Gary D. Wilson, Esquire ,

Niagara Mohawk Power Corporation 300 Erie Boulevard West Syracuse, NY 13202 Supervisor i Town of Scriba Route 8, Box 382 Oswego, NY 13126 i

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