ML17272A745

Final Deficiency Rept Re ECCS Pump Room Flooding.Fuel Pool Cooling Sys Is Not Designed to Seismic Category 1 or Class IE Stds.Fuel Pool Cooling Sys Will Be Upgraded Through re-analysis & Redesign to Improve Reliability

ML17272A745
Person / Time
Site:	Columbia
Issue date:	11/30/1979
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17272A744	List: ML17272A743 ML17272A745
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 7912120418
Download: ML17272A745 (2)

Text

Attachment REPORTABLE DEFICIENCY AND CORRECTIVE ACTION ECCS PUl1P ROON 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 Seismic Category I standards, nor is it Class 1E. 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 I nor Class 1E, it cannot be counted on to pump out the ECCS pump rooms. Even though Class 1E i nstrumentation is available within each ECCS pump room to tell the operator 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 pump out the ECCS pump rooms post-LOCA oi" 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 The Fuel Pool Cooling System wil be upgraded through reanalysis and redesign to improve'eliability. The system will be analyzed to Seismic Category I cri teria and modifi cations will include the addi tion of a safety grade heat sink and emergency power supply.

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