ML20116N691

Provides Updated Info to 841024 Submittal Re Plans for Resolving Generic Issue A-2 on Asymmetric Blowdown Loads. Westinghouse Authorized to Identify & Qualify Applicable Unit 2 Pipe Sections by 850701

ML20116N691
Person / Time
Site:	Prairie Island
Issue date:	04/29/1985
From:	Musolf D NORTHERN STATES POWER CO.
To:	Office of Nuclear Reactor Regulation
References
REF-GTECI-A-02, REF-GTECI-RV, TASK-A-02, TASK-A-2, TASK-OR TAC-8731, TAC-8732, TACS-8731, TACS-8732, NUDOCS 8505070310
Download: ML20116N691 (2)

Text

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Northem States Power Company 414 Ncollet Mall Minneapohs. Minnesota 55401 Telephone (612)330 5500 April 29, 1985 Director Office of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Additional Information Related to Resolution of Generic Task Action Plan Item A-2, Asymmetric Blowdown Loads The purpose of this letter is to provide updated information related to our plans and schedule for resolving Generic Issue A-2 at the Prairia Island Nuclear Generating Plant. This letter supplements and updates the information provided in our submittal of October 24, 1984.

WCAP-10639, forwarded with our October 24, 1984 letter, provides the basis for eliminating postulated large breaks for structural design purposes in Unit No. 1. As reported earlier, the effects of thermal aging for all piping segments in Unit 2 could not be shown to fall under the envelope of thermally aged material for which Westinghouse has fracture toughness data.

To resolve this matter for Unit No. 2, we will authorize additional work to be performed by Westinghouse. This will include:

1. Identify those specific pipe sections in Unit No. 2 not meeting current criteria from a review of as-built drawings.

2. Qualify under present methods all possible Unit No. 2 pipe sections.

3. Perform intensive review of any available new data in an attempt justify less restrictive criteria for the remaining pipe sections in Unit No. 2.

Following completion of this work, Westinghouse will prepare a licensing l topical report (WCAP) for NRC review. This work should be completed by July 1, 1985.

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April 29, 1985 i Page 2- l Northem States Power Company 1 1

-We believe the approach outlined above will meet with acceptance by the NRC Staff. This will permit us to submit a request for exemption from the requirements of GDC-4 of Appendix A to 10 CFR Part 50 as permitted by NRC Generic Letter 84-04 for both Prairie Island units. l 1

Please contact us if you have any questions related to our plans for resolving this matter.

l D d k, David Musolf Manager - Nuclear Suppor Services DMM/ dab c: Regional Administrator-III, NRC NRR Project Manager, NRC Resident Inspector, NRC G Charnoff I

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