ML17272A692

Interim Deficiency Rept Re Failure of Spent Fuel Pool Cooling Sys to Operate During Loca.Sys in Process of Being Upgraded.Final Rept Will Be Forwarded Before 791130

ML17272A692
Person / Time
Site:	Columbia
Issue date:	10/18/1979
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17272A691	List: ML17272A690 ML17272A692
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 7910230484
Download: ML17272A692 (1)

Text

ctober 18, 1979 G02-79,191 Attachment REPORTABLE DEFICIENCY AND CORRECTIVE ACTION ECCS.PUMP ROOtl FLOODING DUE TO FUEL POOL BOIL-OFF Descri tion of the Deficienc During a LOCA or after a safe shutdown. earthquake (SSE) the spent fuel pool cooling system is assumed to fail because it is not designed to

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Seismic Category 1 standards, nor is it Class lE. Eventually, the fuel pool will begin to boil, with the vapor condensing on walls and floors.

This condensate (maximum of 18 gpm) will end up in the floor drain system.

All the sumps in the reactor building. floor drain system are located in the Emergency Core Cooling System (ECCS) pump rooms. Because the reactor building sump pump system is not Seismic Category 1 nor Class lE, it not be counted on'to pump out the ECCS pump rooms.. Even though Class lE can-instrumentation is available within each ECCS pump 'room to tell the oper-ator that the room is flooding, there is no way to stop the source of flooding (fuel pool boiling), to isolate the ECCS pump rooms from the condensate,.and to pump out the ECCS pump rooms post-LOCA or post-SSE.

Eventually, the ECCS pump rooms will flood, shorting out ECCS pumps.

Safet Im lications Loss of any ECCS pump, post-LOCA, due to flooding from fuel pool boiloff, could reduce the number of core cooling pumps below the minimum required to keep the core covered and to keep the suppression pool cool.

Corrective Action Taken WNP-2 is currently evaluating the feasibility of upgrading the spent fuel

.pool cooling system to Seismic Category 1, Class lE requirements to elimi-nate the source of flooding, or qualifying the reactor building floor drain sump system to Seismic Category 1, Class lE requirements so that WNP-2 can take credit for this system to keep the ECCS pump rooms from flooding. A recommendation on this evaluation's. expected by the end of October, 1979.

JAO/10-8-79 VSlD330 gP y'-