ML20085F018

Final Deficiency Rept Re Auxiliary Switches in Breaker Compartments Operating Improperly.Initially Reported on 750115.Caused by Improper Installation.New Arms Installed

ML20085F018
Person / Time
Site:	Browns Ferry
Issue date:	05/09/1975
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Knuth D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
Shared Package
ML20085F015	List: ML20085F018
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8308180216
Download: ML20085F018 (2)

Text

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[v) TENNESSEE VALLEY AUTHORITY 5y (%-1 7M - CH ATT/.NOOGA. TENNESSec 37401 k '/ o.o16[

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May 9, 1975' -

Mr. Donald F. Knuth, Director Office of Inspection and Enforcement U.S. Nucicar Regulatory Commission Washington, DC 20555

Dear !!r. Knuth:

BROWNS FERRY NUCLEAR PLANT UNIT 3 - REPORTAELE DEFICIENCY -

AUXILIARY SWITCllES IN BREAKER COMPART11ENTS OPERATING IMPROPERLY - IE CONTROL NO. II00479F2 ,

Initial report of the subject deficier.cy was made on January 15,

, . 1975, and followed by our February 14, 1975, letter, J. E. Gilleland to Donald F. Knuth. In compliance with paragraph 50.55(e) of i 10 CFR Part 50, we submit the enclosed final report of the

, deficiency. .

Very truly yours, k0? /*)

d / W D'WF J. E. Gilleland Assistant Manager of Power Enclosure CC (Enclosure):

Mr. Norman C. Moseley, Director Office of Inspection and Enforcement U. S. Nucicar Regulatory Commission Region II - Suite 818 230 Peachtree Street, NW.

Atlanta, Georgia 30303 0308180216 750520

< DR ADOCK 0500029 An Equal Opportunity Employer

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• ENCLOSURE BROWNS FERRY WCLEAR PIAliT UNIT 3 IE CONTROL NO. H00479F2 4-kV g}gyrpagH BOARDS - AUXILIARY SWIICHES In BREAKER COMPARTI M S OPERATING I!FROPERLY FINAL REPORT Description of Occurrence On November 19, 1974, the !G switches located on the left-hand side of the unit 3 le kV nhutdcun breaker compartments were found to be overtraveling past the closing The calfunction was discovered during a Point and opening the switch contacts. The breakers had not gene through pre-functional test of the shutdown breckers.

operational testing at that time. .

Caune of Deficiency After investigation, General Electric found that the problem of overtraveling was The anns on the unit 3 !E caused by the novement arn connected to the MH switch. keyed ut the proper 450 angle switches had not been consistent.17

• evertraveled causing the switch contact to open.

Bafety Innlications The MH switches are a part of the circuit device >roviding power to'the unit 3 curc spray pu ps, FJIR P r y , nnd the RER r.ervice unter pu=ps. Failure of the subject breakers vould cause the above equipent to be inoperable.

The deficiency was caused by improper installation. It vs:, discovered during an equipent functional check. The deficiency could not have gone undetected through the series of functional tests and the preop testing of the unit.

Corrective Action The movement arms on the subject switches are oniy used on the unit 3 shutdown boards. The units 1 and 2 shutdown boards use arms of a different cake which do not allow overtravel. New arms have been installed on all unit 3 4-kv' shutdown boards; they have been tested, and now function properly.

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