ML18030A383

Forwards Rept Entitled, PP&L Response to NRC Concerns Re Loss of Spent Fuel Pool Cooling Following Loca,Sses,Units 1 & 2, Per 930708 Meeting

ML18030A383
Person / Time
Site:	Susquehanna
Issue date:	08/16/1993
From:	Byram R PENNSYLVANIA POWER & LIGHT CO.
To:	Chris Miller Office of Nuclear Reactor Regulation
Shared Package
ML18026A429	List: ML18026A428 ML18030A383
References
PLA-4012, NUDOCS 9308170354
Download: ML18030A383 (6)

Text

,. ACCEI ERAT>D DOCUMENT DIST UTION SYSTEM REGULA Y INFORMATION DISTRIBUTI SYSTEM (RIDS)

ACCESSION- NBR!9308170354 DOC.DATE: 93/08/16 ,NOTARIZED: NO DOCKET FACIL:50-387 Susquehanna Steam Electric Station, Unit 1, Pennsylva 05000387 50-388 Susquehanna Steam Electric Station, Unit 2, Pennsylva 05000388 AUTH. NAME AUTHOR AFFILIATION BYRAMgR.G. Pennsylvania Power & Light Co. R RECIP.NAME RECIPIENT AFFILIATION MILLERgC.L. Project Directorate I-2

SUBJECT:

Forwards rept entitled, "PP&L Response to NRC Concerns re Loss of Spent Fuel Pool Cooling Following LOCA,SSES,Units 1

& 2," per 930708 meeting.

DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR I ENCL t SIZE: 3 TITLE: OR Submittal: General Distribution NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PDl-2 LA 1 1 PD1-2 PD 1 1 CLARK,R 2 2 D

INTERNAL: ACRS 6 6 NRR/DE/EELB 1 '1 NRR/DRCH/HICB 1 1 NRR/DRPW/OTSB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NUDOCS-ABSTRACT 1 1 OC ZEDCB 1 0 OGC/HDS2 1 0 REGAL 01 1 1 EXTERNAL: NRC PDR 1 1 NSIC 1 1 D

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Pennsylvania Power 8 Light Company Two North Ninth Street ~ Allentown, PA 18101-1179 ~ 215/774-5151 Robert G. Byram Senior Vice President-Nuclear 21 5/774-7502 AUG 16 1993 Director of Nuclear Reactor Regulation Attention: Mr. C. L. Miller, Project Director Project Directorate I-2 Division of Reactor Projects U.S. Nuclear Regulatory Commission Washington, D.C. 20555 SUSQUEHANNA STEAM ELECTRIC STATION INFORMATIONON SPENT FUEL POOL COOLING Docket Nos. 50-387 PLA-4012 FILE A17-8 and 50-388

References:

1. PLA-3978, RG. Byram to C.L. Miller, Request for Additional Information on the Effects of a Loss of Spent Fuel Pool Cooling Event Following a Loss of Coolant Accident", dated May 24, 1993.

2. PLA-3996, RG. Byram to C.L. Miller, "Information on Licensing Basis of Spent Fuel Pool Cooling System", dated July 6, 1993.

Dear Mr. Miller:

On July 8, 1993, PP&L met with the NRC to discuss the design and operation of the Spent Fuel Pool Cooling systems installed in Susquehanna SES Units 1 and 2. During the course of this presentation, we provided updated technical information since the Reference 1 submittal, and discussed PP&L's position on the SSES licensing basis as documented in Reference 2. Our major conclusions regarding the postulated accident scenario (design basis LOCA coupled with an extended loss of Spent Fuel Pool Cooling) were as follows:

~ Time to boil is much greater than 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> at any point when the conditions presented by the accident scenario become a concern. Immediate operator actions are not required to restore spent fuel pool cooling. Sufficient time will be available to take appropriate operator actions to restore spent fuel pool cooling and prevent boiling.

~

Cooling can be restored prior to boiling by either restoration of the normal Spent Fuel Pool Cooling system, or the safety-related, diesel-backed RHR system in Fuel Pool Cooling Mode.

F'DR 9308i70354 9308ih PDR ADOCK 05000387

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FILE A17-8 PLA-4012 Mr. C. L. Miller

~ The Emergency Service Water valves that support makeup to the Spent Fuel Pool have been determined to be accessible (i.e. < 5 Rem), even if a Regulatory Guide 1.3 source term is assumed.

~ Emergency Service Water makeup to one Spent Fuel Pool will eventually fill both pools.

Therefore, access to the accident unit is not required to provide makeup water to its Spent Fuel Pool.

~ Access to the non-LOCA unit is always assured due to the capability to isolate its ventilation system from the accident unit using controls that exist in the main control room.

~ Removing the cask storage pit gates will provide capability to utilize the non-LOCA unit Spent Fuel Pool Cooling system ifavailable, or the RHR Fuel Pool Cooling Mode ifit is not.

~ Even ifthe Spent Fuel Pool is assumed to boil and no operator action to restore cooling occurs for 30 days, the resultant environmental impacts will not prevent adequate long term core cooling from being maintained.

~ Procedures have been improved and operators have been trained to assure the proper response to a loss of Spent Fuel Pool Cooling. Modifications to install improved level and temperature indication to the Spent Fuel Pools, although not required to meet the Licensing Basis of Susquehanna SES, are being pursued in order to further strengthen the operator response to this event. These modifications also address previous recommendations made by our internal assessment group to add level and temperature indication to assist the operators in daily operation of the fuel pool cooling system.

~ The Licensing Basis of Susquehanna SES considers loss of spent fuel pool cooling resulting in pool boiling to be initiated from a seismic event, not a LOCA, and this is in compliance with regulatory requirements.

~ The SSES Licensing Basis is acceptable due to the lack of a need for immediate operator action to restore spent fuel pool cooling, the extremely low probability of a DBA LOCA coupled with an extended loss of pool cooling (per the SSES IPE this is on the order of 10E-15), and the fact that ensuring that the spent fuel is kept water covered is an operator priority.

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FILE A17-8 PLA-4012 Mr. C. L. Miller The attached report provides further documentation of the details behind the above conclusions, and is provided in response to your request at the July 8 meeting. If you should have any questions on this material, please contact us.

Very truly yours,

.G.B r Attachment cc: PRC Document ControLDeait (original)

NRC Region I Mr. G. S. Barber, NRC Sr. Resident Inspector - SSES Mr. R. J. Clark, NRC Sr. Project Manager - Rockville