05000318/LER-1981-010-03, /03L-0:on 810301,power-operated Relief Valve ERV-402 Failed to Seat Resulting in Valve Isolation.Caused by Insufficient Pressure in Sys While Filling Rcs.Pressure Raised & Valve Seated

/03L-0:on 810301,power-operated Relief Valve ERV-402 Failed to Seat Resulting in Valve Isolation.Caused by Insufficient Pressure in Sys While Filling Rcs.Pressure Raised & Valve Seated

ML19347D571
Person / Time
Site:	Calvert Cliffs
Issue date:	03/17/1981
From:	Rayburn C, Wenderlich R BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19347D569	List: 05000318/LER-1981-010, Forwards LER 81-010/03L-0 05000318/LER-1981-010-03, /03L-0:on 810301,power-operated Relief Valve ERV-402 Failed to Seat Resulting in Valve Isolation.Caused by Insufficient Pressure in Sys While Filling Rcs.Pressure Raised & Valve Seated
References
LER-81-010-03L-01, LER-81-10-3L-1, NUDOCS 8103260645
Download: ML19347D571 (2)

LER-1981-010, /03L-0:on 810301,power-operated Relief Valve ERV-402 Failed to Seat Resulting in Valve Isolation.Caused by Insufficient Pressure in Sys While Filling Rcs.Pressure Raised & Valve Seated

Event date:
Report date:
3181981010R03 - NRC Website

text

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EVENT OESCRIPTICN AND PROS A3LE CONSECUENCES h Ia !2I i During Mode 5 cceration at 1430, isolated ERV-402 a cower-ocerated re-I u

lief valve (PORV), due to leakage cast the valve. This was a degrada-

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leaking shortly af ter the Reactor Ccolant System (RCS) was filled.

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ioi3l l pressure was then raised to about 150 csig to reseat the valve.

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3 is i i jaj7!l ERV-402 was unisolated and reseated. The redundant PORY and code safety I

valves remained operable durino this non-recetitive event.

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action was taken.

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ti ii i i system pressure to build pressure in the main valve pressure chamber I

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50-313 LICENSE NO.

DPR-69 EVENT DATE 03-01-31 REPORT DATE 03-17-81 ATTACHMENT EVENT DESCRIPTION AND PROBABLE CONSEOUENCES (CONT'D)

During Mode 5 operation at 1430, isolated ERV-402, a power-operated relief valve (PORV) due to leakage past the valve. This was a degradation of the requirements of T.S. 3.4.9.3.a. This valve was found to be leaking shortly af ter the Reactor Coolant System filled. Reactor Coolant System pressure was then raised to about 150 psig to reseat the valve. At 1700, ERV-402 was unisolated and reseated. The redundant PORV and both code safety valves remained operable during this event. This event had no inpact on the public health or safety. This is a non-repetitive event.

CAUSE DESCRIPTION AND CORRECTIVE ACCIONS (CON'D)

The power-operated relief valve (PORV) was seated when the Reactor Coolant System (RCS) pressure was raised. No specific maintenance action was taken. It is believed that the valve failed to ; eat because the PORV main valve is designed to close with the build up of steam pressure in the main valve pressure chamber. With the pilot valve closed, the pressure in

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the chamber forces the valve disc closed.

While filling the RCS there was insufficient pressure in the system to close the valve disc. Af ter the RCS pressure was raised, the valve was unisolated and it seated. No further corrective action is deemed necessary at this tim:

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