ML20085G076

Interim Deficiency Rept Re Derating of 250-volt Fuses in 4-kV & 480-volt Switchgear.Initially Reported on 750129. Evaluation & Proposed Corrective Actions Awaited from Ge. Final Rept Anticipated by 750331

ML20085G076
Person / Time
Site:	Browns Ferry
Issue date:	02/28/1975
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Knuth D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
Shared Package
ML20085G057	List: ML20085G058 ML20085G061 ML20085G076
References
NUDOCS 8308240238
Download: ML20085G076 (1)

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February 28, 1975 Mr. Donald F. Knuth, Director Office of Inspection and Enforcement

., U.S. Nuclear Regulatory Commission Washington, DC 20545

Dear Mr. Knuth:

BROWNS FERRY NUCLEAR PLANT UNIT 3 - REPORTABLE DEFICIENCY -

DERATING OF 250-VOLT FUSES IN 4-kV AND 480-VOLT SWITCHGEAR Initial  ; ort of the subject deficiency was made on January 29, 1975. In compliance with paragraph 50.55(e) of 10 CFR Part 50, this is submitted as an interim report.

On January 29, 1975, it was discovered that most of the installed l fuses in the 250-volt de control circuits of the 4-kV and l 480-volt switchgear are one-time class H 250-volt fuses of

Bussmann or Economy manufacture. This class of fuse has been derated to 250-volt ac only. As a result the subject fuses are no longer appropriate for 250-volt de service.

These fuses were supplied by the General Electric Company, and we are awaiting their evaluation and proposed corrective measures.

We expect that wo should be able to provide the final report by March 31, 1975.

Very truly yours, l s

! 2 $.v-([

J. E. Gilleland Assistant Manager of Power l CC: Mr." Norman C. Moseley, Director

, Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission

Region II - Suite 818 230 Peachtree Street, hv.

Atlanta, Georgia 30303 h0h S

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1. 'y 'h An Equal Opportunity Ernplover

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