05000220/LER-1980-023-03, /03L-0:on 800922,111 Absolute Filter Access Cover Was Found Off Housing.Caused by Residual Pressure in Containment Nitrogen Inerting Line Pressurizing Filter Housing When Torus Venting Initiated.Cover Reinstalled

/03L-0:on 800922,111 Absolute Filter Access Cover Was Found Off Housing.Caused by Residual Pressure in Containment Nitrogen Inerting Line Pressurizing Filter Housing When Torus Venting Initiated.Cover Reinstalled

ML18037A295
Person / Time
Site:	Nine Mile Point
Issue date:	10/20/1980
From:	Harrison P NIAGARA MOHAWK POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML17053C038	List: 05000220/LER-1980-023, Forwards LER 80-023/03L-0 05000220/LER-1980-023-03, /03L-0:on 800922,111 Absolute Filter Access Cover Was Found Off Housing.Caused by Residual Pressure in Containment Nitrogen Inerting Line Pressurizing Filter Housing When Torus Venting Initiated.Cover Reinstalled
References
LER-80-023-03L, LER-80-23-3L, NUDOCS 8010300463
Download: ML18037A295 (4)

LER-1980-023, /03L-0:on 800922,111 Absolute Filter Access Cover Was Found Off Housing.Caused by Residual Pressure in Containment Nitrogen Inerting Line Pressurizing Filter Housing When Torus Venting Initiated.Cover Reinstalled

Event date:
Report date:
2201980023R03 - NRC Website

text

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EVENT DESCRIPTION

Following a plant start-up the reactor primary containment inerting process had been completed.

In order to establish the proper drywell to torus differential pressure the appropriate valves were opened to vent the torus through fill Emergency Ventilation System.

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rounds,

//111 absolute filter access cover was found off the housing.

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS Apparently residual pressure in the containment nitrogen inerting line pressurized the filter housing when torus venting was initiated.

The affected system was declared inoperable and the redundant system was run for operability.

The housing cover was immediately reinstalled and the affected system was subsequently run for operability.

For long term corrective action a caution will be added to the containment inerting operating procedure to ensure residual pressure is removed from the inerting line immediately at the end of the inerting operation and prior to drywe11/torus venting.