ML20209G218

Forwards AEOD/E511, Closure of ECCS Min Flow Valves, Engineering Evaluation Rept.Suggests IE Issue Info Notice Reminding Licensees That Min Flow Bypass Function Provides Essential Pump Protection Feature

ML20209G218
Person / Time
Site:	Peach Bottom, Brunswick, 05000000
Issue date:	08/15/1985
From:	Ippolito T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Vollmer R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
Shared Package
ML20209G223	List: ML20209G218 ML20209G287 ML20209G305
References
AEOD-E511, NUDOCS 8509190175
Download: ML20209G218 (2)

Text

. c P D(L August 15, 1985 AE0D/E511 MEMORANDUM FOR: Richard H. Vollmer, Deputy Director Office of Inspection and Enforcement FROM: Thomas A. Ippolito, Deputy Director Office for Analysis and Evaluation of Operational Data

SUBJECT:

CLOSURE OF EMERGENCY CORE COOLING SYSTEM MINIMUM FLOW VALVES Enclosed is an AEOD engineering evaluation report concerning several recent events involving the inadvertent closure of one or more Emergency Core Cooling System minimum flow valves. From these events and an analysis of the LER data base, we have concluded that not all licensees may recognize the importance of minimum flow valves to Emergency Core Cooling System pump operability. It is suggested, therefore, that the Office of Inspection and Enforcement consider issuing an information notice which reminds licensees that the minimum flow by-pass function provides an essential pump protection feature and that ECCS pump operability is dependent on minimum flow valve operability. One of the events studied also involved the discovery of inadequate control logic for minimum flow valves to meet their containment isolation function. It is suggested, therefore, that the information notice also urge licensees to review the control logic of the ECCS minimum flow valves to ensure that it is adequate to satisfy containment isolation requirements, where applicable.

Finally, we would like to bring to your attention a recent 10 CFR Part 21 report (attachment) received from the Wisconsin Electric Power Company describing a design deficiency discovered at the Point Beach Nuclear Plant and involving the control circuitry for the recirculation isolation valves for the safety injection pumps. The Part 21 report indicates that the failure of a single component in the control circuitry for the valves could, under specific circumstances, result in the failure of the safety injection pumps due to a loss of minimum flow protection. Although not addressed in the enclosed engineering evaluation report, the design deficiency discovered at the Point Beach Nuclear Plant could also be considered for inclusion in an information notice on the subject of ECCS minimum flow valves.

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.If you or your staff. have any questions concerning the enclosed engineering evaluation report, please contact Eric Leeds of my staff on extension 24445.

Original signed by Thomas A. jppchta Thomas A. Ippolito, Deputy Director Office for Analysis and Evaluation ,

of Operational Data

Enclosure:

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As stated cc: w/enclor,ure E. Jordan,.IE E. Rossi, IE R. Baer, IE G. Holahan, NRR d

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