ML20085G911

AO BFAO-50-260/7418W:on 741015,2B Standby Liquid Control Pump Relief Valve Opened at Less than Specified Setpoint. Caused by Foreign Matl Under Valve Seat.Relief Valve Removed & Tested.Foreign Matl Removed During Testing

ML20085G911
Person / Time
Site:	Browns Ferry
Issue date:	10/24/1974
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Case E US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G914	List: ML20085G911 ML20085G920
References
NUDOCS 8308290511
Download: ML20085G911 (2)

Text

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Mr. Edson G. Case \j his$}

- i Acting Director of Licensing  % /

Office of Regulation D' -4

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U.S. Atomic Energy Co= mission i Washington, DC 20545 -

l D' ear Mr. Case:

TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT UNIT 2 -

DOCKET NO. 50-260 - FACILITY OPERATING LICENSE DPR ABNORMAL OCCURRE:ICEREPORTBFAO-50-260/7416W The enclosed report is to provide details concerning 2B standby liquid control pu=p relief valve which opened at less than the specified setpoint during a routine surveillance test and is submitted in accordance with Appendix A to Regulatory Guide 1.16, Revision 1, October 1973. This event occurred on Browns Ferry Nuclear Plant unit 2 on October 15, 1974.

Very truly yours, TENNESSEE VALLEY AUTHORITY

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Er/ W

/s.b1. Thomas Director of Power Production Enclosure '

CC (Enclosure):

Mr. Norman C. Moseley, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, IM., Suite 818 Atlanta, Georgia 30303 8308290511 741024 PDR ADOCK 05000260 11.,9 [ '

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ABh0RMALOCCURRENCEREPORT Report No.: EFAO-50-260/7418W Report Date: October 24, 1974 Occurrence Date: October 15, 1974 Facility: Browns Ferry Nuclear Plant unit 2 Identification of occurrence During a routine surveillnrice test, 2B standby liquid control pu=p relief valve opened at less than the specified setpoint.

Conditions Prior to Occurrence '

The reactor was in the cold shutdown condition.

Description of Occurrence At 0415 hours0.0048 days <br />0.115 hours <br />6.861772e-4 weeks <br />1.579075e-4 months <br /> on October 15, 1974, during a routine surveillance test, 2B liquid control pu=p relief valve failed to open at the prescribed technical specification requirement of 1,425 1 75 psig; and the valve appeared to be leaking through at approxi=ately 200 psi.

Designation of Am)arent Cause of Occurrence J 5

The apparent cause of the failure was the preseneg.of foreign material under the valve seat which let the relief valve start relieving at a pressure lower '

than the setpoint.

i Analysis of occurrence \

(

The unit was in the cold shutdown condition at the time the low setpoint was i discovered. If standby liquid control injection had been required, injection would have been possible under these conditions as the valve lifted at 1,250 psi. In addition, the "A" loop was operable and was available if needed. n b

There was no damage to other syste=s, components, or structures as a result of the low setpoint. There were no adverse effects to the public health or safety as a result of the occurrence. -

Corrective Action I s

,t The relief valve was removed and visually inspected. There was no deposit or ,

foreign caterial noted but the valve had been flushed during testing. The valve was bench setpoint checked using water as a test medium. -It was then {

remounted on the standby liquid control header, and the lifting pressure was checked. The valve lifted at 1,400 psi which meets the technical specification require =ents, j

Failure Data Crosby Valve and Gage Company Style - J!&K Size - 1 x 2

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Shop No. - 50785 Y2

• Resent Press - 1,270 psi I Cap - 56 GPM H O @ 1,680 2

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