ML17266A012

LER#78-040/03L-0 on 781002:During Pwr oper,1B Charging Pump Failed to Start While Only 1C Pump Was operable.Cause:1B Suction Pressure Gage Waspegged Highdue to Leaking Valve. Valve Repaired,Gage Vented & Pump Returned to Svc

ML17266A012
Person / Time
Site:	Saint Lucie
Issue date:	11/01/1978
From:	Schoppman M FLORIDA POWER & LIGHT CO.
To:
Shared Package
ML17206A504	List: ML17206A503 ML17266A012
References
LER-78-040-03L, LER-78-40-3L, NUDOCS 7811080217
Download: ML17266A012 (2)

Text

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REPORTABLE OCCURREHCE 335-78-40 LICENSEE EVENT REPORT PAGE TWO Additional Cause Descri tion and Corrective Action The cause of the occurrence was the untimely operation of an electric interlock on the pump suction pressure gage. The purpose of the interlock is to prevent the pump from starting if suction pressure is too low. It has been. determined that, prior to this Reportable Occurrence, the suction pressure gage had been operated beyond its normal range and "pegged high". The next time a pump start was attempted, the electric interlock interpreted the overtravelled,or pegged-high, position of the suction gage as a zero-pressure indication and prevented the pump from starting.

The suction pressure gage was pegged high because of a leaking relief valve on the discharge side of the pump. The relief valve relieves back to the suction side and had been leaking the previous time the pump was operated. The leaking relief valve had allowed pressure pulses to be transmitted back to the suction side of the pump. These pressure pulses caused the suction pressure gage to peg high.

The relief valve was repaired and the suction pressure gage was vented to normal suction pressure. The lB charging pump was then started and operationally checked satisfactorily.