ML20003E419

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Interim Deficiency Rept Re Spurious Opening of Turbine Bypass Valves,Initially Reported 810309.Opening of Valves Could Result in DNBR Limits Being Exceeded.Also Reported Per Part 21
ML20003E419
Person / Time
Site: North Anna Dominion icon.png
Issue date: 03/30/1981
From: Spencer W
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, 190, NUDOCS 8104030430
Download: ML20003E419 (1)


Text

Vepco _ . . _ , . _ _ . . _ . . . . _ _ , . . . . . . . _

March 30, 1981 Mr. James P. O'Reilly, Director Serial No. 190 Office of Inspection & Enforcement PSE&C/WBR/adw: wang U. S. Nuclear Regulatory Comission Region II Docket No. 50-404 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

On March 9, 1981, a report was made under the provisions of 10CFR50.55(e) and 10CFR21, coricerning the spurious opening of the turbine bypass valves.

A single failure in the steam pressure sensing instrumentation or the NSS control u rcuitry could result in the spurious opening of the turbine bypass valves. This event has the impact of a steam line break smaller than the large steam line break analyzed in the PSAR but larger than that of a single stuck open valve; however, the spurious opening of the turbine bypass valves has a higher probability of occurrence than the other events. Although plant specific analyses have not been performed for our 145FA unit, based on B&W analysis of 205FA plants, the spurious opening of the turbine bypass valves could result in DNBR limits being exceeded.

Vepco will be investigating this problem in the future. The NRC will be notified of any modifications and/or analyses neces;;ary to resolve this potential safety concern.

This report is forwarded as required by 10CFR50.55(e) and is an interim report on this subject.

Very tr y yours, l.(,/C wn-r - /

W.C.$ pencer Vice President - Power ' tation Engineering and Construction Servic..

cc: Mr. Robert L. Tedesco Division of Licensing 8104030 9 0 5