ML20134G010
| ML20134G010 | |
| Person / Time | |
|---|---|
| Issue date: | 08/19/1985 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Fulton J BOSTON EDISON CO., BWR OWNERS GROUP |
| Shared Package | |
| ML20134G013 | List: |
| References | |
| NUDOCS 8508220244 | |
| Download: ML20134G010 (1) | |
Text
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f AUG i s 1985 Mr.1/nn M. Fulton, Chaiman DISTRIBUTION BWR Owner's Group Central File w/inc. Connie /DCrutchfield Boston Edison Company NRC PDR w/inc. GHolahan Pleech 25 Braintree Hill Office Park NSIC w/inc. JHannon Braintree, Massachusetts 02184 ORAB Rdg RKarsch HThompson/FMiraglia HSmith
Dear Mr. Fulton:
PPAS HDenton/DEisenhut In your letter dated July 16, 1985, you expressed concern that certain options in interpretation of the NRC rule on Anticipated Transients Without Scram (ATWS), 10 CFR 50.62 would result in excessively restrictive Technical Specification Limiting Conditions of Operation, extensive plant modifications or additional possible shutdown costs. I am providing herein, additional guidance regarding Standby Liquid Control System (SLCS) implementation and Technical Specification requirements in answer to your concern.
The specific question concerning the SLCS is: If two pumps are needed to meet the 86 gpm equivalency requirement and one or both are out of service, does the Technical Specification Action Statement in place at each plant require changes to comply with the ATWS Rule? The Technical Specification Action Str.tement regarding SLCS pump operability now requires that both pumps be cperable or enter an LCO, e.g. if only one pump is operable a restrictive condition is imposed, and if neither pump is operable a very restrictive condition is imposed. The SLCS is a backup to a safety related system which is highly reliable. Additional levels of defense are also provided by backup scram valves and an alternate rod insertion system. For this reason, SLCS and other ATWS mitigating systems have not been required to be safety related.
Further, the incremental change in risk which would derive from modifying the limiting conditions for operation for pump operability is very small.
Therefore, the Technical Specifications as presently written are adequate and need not be changed.
It should be noted that the Technical Specifications do not address the backup scram system and alternate rod insertion system, nor are such plant-specific ATWS features as automatic initiation of the SLCS addressed.
Technical Specification requirements for ATWS mitigating systems are under review as part of the Technical Specification Improvement Program. Further guidance in these areas will be forthcoming in the Fall of 1985.
Sincerely, 8508220244 850819 on M Ses d W PDR TOPRP ENV9ENE H R,4 ,
C PDR ~
Harold R. Denton, Director Office of Nuclear Reactor Regulation
- SEE PREVIOUS CONCURRENCE SHEET.
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