ML19318D073

RO 80-044/01T:design for Steam Generator Snubber Embedment Found Not to Reflect as-constructed Condition, Resulting in Nonconservative Loads for Anchors.Caused by Assumption That Load Was Applied to Normal Surface

ML19318D073
Person / Time
Site:	Beaver Valley
Issue date:	06/30/1980
From:	Werling J DUQUESNE LIGHT CO.
To:
References
BVPS:JAW:902, NUDOCS 8007070296
Download: ML19318D073 (2)

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$'i P DUQUESNE LTCllT C0!!PANY Beaver Valley Power Station Post Office Box 4 Shippingport, PA 15077 June 30, 1980 BVPS: JAW:902 Beaver Valley Power Station, Uni.t Nu. 1 Docket No. 50-334, License No. DPR-66 LER 80-044/01T Mr. B.11. Grier, Director Of Regulation United States Nuclear Regulatory Commission Region 1

• 631 Park Avenue

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King of~ Prussia, Pennsylvania 19406

Dear Mr. Grier:

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In accordance with Appendix A, Beaver Valley Technical Specifications, Licensee Event Report LER 80-044/0lT, Technical Specification 6.9.1.9.b, Administrative Controls, is submitted.

Duquesne Light Company has been informed by the BVPS Unit 1 Architect-Engineer that the existing steam generator snubber embedmcut design does not reflect the "as constructed" condition of the embedment. The original calculations assumed that the load was applied normal to the embedment surface, I rather than skcued. The original calculation considered loads due to pipe I break and scismic. However, these calculations were not updated to reflect the revised sei,smic loads and loads associated with asymetric pressure due to a break within the boundary of the neutron shic?d tank. The result was the establishment of non-conservative' loads for the embedment anchors. The Architect-Engineer has been pursuing an analytical approach to evaluate the

. skewed load application. In addition, they have reviewed the hot leg pipe break loads which were supplied by Westinghouse for Beaver Valley Unit 1 and found that they are significantly higher than comparable loads supplied for Beaver Valley Unit 2. Duquesne Light Company has contracted with Westinghouse to generate new pipe break loads based on the latest analytical techniques. The field is also presently determining the actual in-place concrete strength at the embedments.

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llVPS: JAW:902 Page 2 -

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Based on 1) the anticipated reduction in loads from Westinghouse, 2) the expectation that the in-place _ concrete strenth will be in excess of the design valve of_3000 PSI and 3) a revised analytical approach, it is believed that the embedment will be satisfactory and that a portion of the conservatism thought to be in the original analysis retained.

Our investigation is continuing and more information will be supplied in our follow-up report.

Very truly yours,

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PWALs J. A. Worling

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• v Superintendent cc: Director of Management & Program Analysis v/'

United States Nuclear Regulatory Commission Washington, D. C. 20555 ,

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D. L. Wigginton, BVPS Licensing Project Manager United States Nuclear Regulatory Commission

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Washington, D. C. 20555 D. A. Beckman, Nuc1 car Regulatory Commission, BVPS Site Inspector G. A. Olson, Secretary, Prime Movers Committee - EEI Hr.. John Alford, PA Public Utilities Commission, liarrisburg, PA 4

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