ML17272A759

Final Deficiency Rept Re Spent Fuel Pool Cooling Sys.Spent Fuel Sys Not Designed to Seismic Category I Stds.Cooling Sys Will Be Upgraded

ML17272A759
Person / Time
Site:	Susquehanna, Columbia
Issue date:	11/30/1979
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17272A757	List: ML17272A758 ML17272A759
References
NUDOCS 7912280651
Download: ML17272A759 (2)

Text

Attachment REPORTABLE DEFICIENCY AND CORRECTIVE ACTION

, ECCS PUMP ROOM 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 lE instrumentation 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 Eventually, the ECCS pump rooms will flood, shorting out ECCS oi'ost-SSE.

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 reliability. The system will be analyzed to Seismic Category I cri teria and modifi cations will include the addition of a safety grade heat sink and emergency power supply.

'1<