ML20085H164

AO BFAO-50-260/748W:on 740819,RCIC Pump Suction Valve FCV-2-71-18 Failed.Caused by Frozen Torque Switch.Torque Switch Replaced

ML20085H164
Person / Time
Site:	Browns Ferry
Issue date:	08/29/1974
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8308300293
Download: ML20085H164 (2)

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[. TENNESSEE VALLEYTENNESSEE AUTHO AITY f k 2:"""J i ~ 'f rA CHATTANCOGA, 3740'I L 'll?

August 29, 1974

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Mr. John F. O' Leary, Director N Directorate of Licensing Office of Regulation 50-260 U.S. Atomic Energy Comnission Washington, DC 20545

Dear Fr. O' Lear /:

TmliESSEE VAIJLEY AUTHORITI - BROGS FERR'I ITUCLEAR PLAHT UNIT 2 -

DOCKET NO. 50-260 - FACILITI OPERATING LICENSE DPR ABNORMAL OCCURRMCE REPORT BFAO-50-260/748W The enclosed report is to provide details concerning failure of RCIC pumo suction valve FCV-2-71-18 and is submitted in accordance with Appendix A to Regulator / Guide 1.16, Revision 1, October 1973 This

, event occurred on Browns Ferry Nuclear Plant unit 2 on August 19, 1974.

Very truly yours, TENNESSEE VALLEY AUTHORITY

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, E. F. Thocas Director of Power Production Enclosure CC (Enclosure):

Mr. Norman C. Moseley, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, MT., Suite 818 Atlanta, Georgia 30303 ~ ,QO r, #

8308300293 740829 g DR ADOCK 05000260 "8

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ABITOPJ/.AL OCCURECE REF0FT Report No.: BFAO-50-260/7h8W Report Date: August 29, 1974 Occurrence Date: August 19, 197h Facility: Browns Ferry Nuclear Ple.nt - Unit 2 Identification of Occurrence RCIC pu=p suction valve FCV-2-71-18 failure.

s Conditions Prior to Occurrence The reactor was in a cold shutdown condition.

Description of Occurrence On August 19,197h, it was discovered that the thermal overloads in the : otor control circuit for FC7-2-71-lS, RCIC pu'o torus cuction valve had tripped.

Subsequent investigation showed that the valve had jae:med in the closed position.

Designation of Apparent Cause of Occurrence The cause of the failure was a torque switch that was frocen up and would not operate.

Analysis of Occurrence At the ti e of this vnive fC. lure, the unit ne in e col' :hutdo,m conlition.

As a result ECIC was noe aveilable for operation, lhd the unit been in operation, ROIC would have been able to obtain suction fron the condensate storage tank.

Corrective Action The failed torque switch was replaced with a new, similar one. The limit switches were also replaced because of indicated corrosion buildup. The limits and tor,que setting were set and the valve cycled satisfactorily.

Failure Data The torque switch and the limit switches that were replaced are for n Limitorque Operator, Type S';'3-00.

There are no other known failures of this type at the present tir.e.

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