ML20082A130

Forwards Revised Response to IE Bulletin 83-03 Re Check Valve Failures in Raw Water Cooling Sys of Diesel Generators.Check Valves Will Be Modified to Require Backflow Testing of Diesel Generator Check Valves by 840101

ML20082A130
Person / Time
Site:	Browns Ferry
Issue date:	11/07/1983
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-SSINS-6820 IEB-83-03, IEB-83-3, NUDOCS 8311180063
Download: ML20082A130 (2)

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, TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 374ol 400 Chestnut Street Tower II November 7, 1983 U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

INSPECTION AND ENFORCEMENT BULLETIN 83 CHECK VALVE FAILURES IN RAW WATER COOLING SYSTEMS OF DIESEL GENERATORS - BROWNS FERRY NUCLEAR PLANT By my letter to you dated June 15, 1983 we submitted response to IE Bulletin 83-03 for the Browns Ferry Nuclear Plant. In telephone discussions with your ataff we were informed that the response'was unacceptable. We have reevaluated our situation and are submitting our revised response.

This matter was included as an open item in IE Inspection Report 83-32 dated September 12, 1983 If you have any questions, please call Jim Domer.at FTS 858-2725.

To the best of my knowledge, I declare the statements contained herein are complete and true.

Very 'ruly c yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, <ianager Nuclear Licensing Enclosure cc: U.S. Nuclear Regulatory Commission (Enclosure)

Document Control Desk Washington, D.C. 20555 0311180063 031107 ll PDR ADOCK 05000259 g . J-PDR I l 5D-239 An Equal Opportunity Employer

I ENCLOSURE REVISED RESPONSE TO IE BULLETIN 83-03 DATED MARCH 10, 1983 BROWNS FERRY NUCLEAR PLANT Response to Item 2 The check valve arrangement for diesel generators (D/0) at Browns Ferry Nuclear Plant (BFN) is quite different from that found at Dresden and Quad Cities where the reported failures occurred. Each D/G at BFN is supplied by two separate sources of emergency equipment cooling water (EECW). Each of these two sources of EECW is capable of supplying the minimum flow required for diesel operability. With a single source of EECW capable of supplying the necessary flowrate, a double passive failure (one check valve in each EECW supply) on.a single,D/G'would be necessary to render the diesel inoperable. The high improbability of such an event indicates that the current test procedures are sufficient to maintain D/G operability. However, for added conservatism, the section XI IST instruction that requires forwardflow testing of the EECW check valves will be modified to require backflow testing of the D/G check valves. The backflow test frequency will be quarterly, the same as the forwardflow test frequency.

Response to Item 3 The appropriate plant test instruction will be modified and performed by January 1, 1984.

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