DCL-84-364, Advises That Util Response to Item 4.5.3 of Generic Ltr 83-28, Reactor Trip Sys Functional Testing Interval, Contained Entirely in Westinghouse WCAP-10271 Re Reactor Protection Instrumentation Sys,Currently Under NRC Review

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Advises That Util Response to Item 4.5.3 of Generic Ltr 83-28, Reactor Trip Sys Functional Testing Interval, Contained Entirely in Westinghouse WCAP-10271 Re Reactor Protection Instrumentation Sys,Currently Under NRC Review
ML20100A891
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 11/30/1984
From: Shiffer J
PACIFIC GAS & ELECTRIC CO.
To: Knighton G
Office of Nuclear Reactor Regulation
References
CON-#185-535 DCL-84-364, GL-83-28, OL, NUDOCS 8412040120
Download: ML20100A891 (2)


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PACIFIC GAS AND E LE C T RIC C O M PANY f bbM l 77 BEALE STREET . SAN FRANCISCO, CALIFORNIA 94106 . (415)781 4211 . TWX 910-372 6587 November 30, 1984 PGandE Letter No.: DCL-84-364 Mr. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Re: Docket No. 50-275, OL-DPR-80 Docket No. 50-323 Diablo Canyon Units 1 and 2 Generic Letter 83-28, Item 4.5.3 Reactor Trip System Functional Testing Interval

Dear Mr. Knighton:

Item 4.5.3 of Generic Letter (GL) 83-28 requires that licensees review existing intervals for on-line functional testing of the reactor trip system, with a view to maximizing system reliability. If current intervals are not optimum, GL 83-28 requests that Technical Specification changes be proposed for NRC review.

In January 1983, the Westinghouse Osners Group (WOG) submitted WCAP-10271,

" Evaluation of Surveillance Frequencies and Out of Service Times for the Reactor Protection Instrumentation System," for NRC review. The WCAP report evaluates the impact of current and extended surveillance intervals on unavailability of the reactor protection system including the reactor trip system. The evaluation considers the effects of common mode failure, operator error, reduced redundancy during testing, and equipment bypass. Correlative effects on plant operation and safety were also considered, including required manpower, inadvertent trips during testing, and distraction from plant monitoring on the part of the control room operators and shift supervisor.

Supplement 1 to WCAP-10271 extended the evaluation with a discussion of component wearout caused by testing. A third WOG submittal supported the conclusions of WCAP-10271 and answered NRC questions. The NRC is currently reviewing the WOG submittals, and a final NRC evaluation is anticipated shortly.

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Mr. G. W. Knighton PG:ndE Letter No. DCL-84-364 Novemb;r 30, 1984 e Page 2 These three WOG submittals have provided all the information requested in Item 4.5.3 of GL 83-28 They conclude that less frequent testing would result in improved overall plant safety and equipment reliability. PGandE also agrees with these conclusions. Once the final NRC evaluation of WCAP-10271 is published, PGandE will propose the Technical Specification changes recommended in the WCAP report.

Kindly acknowledge receipt of this material on the enclosed copy of this letter and return it in the enclosed addressed envelope.

Sincerely, J. Shiffer cc: Service List

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