ML20138S100

Forwards Preliminary Case Study Rept, Effects of Ambient Temp on Electronic Equipment in Safety-Related..., for Review.Rept Initiated by 840604 Event Re Total Loss of Control Area Ventilation Sys

ML20138S100
Person / Time
Site:	McGuire, Mcguire
Issue date:	11/06/1985
From:	Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Rossin D NUCLEAR SAFETY ANALYSIS CENTER
Shared Package
ML17299B323	List: ML20138S096 ML20138S100 ML20138S103
References
REF-GTECI-A-44, REF-GTECI-EL, TASK-A-44, TASK-OR NUDOCS 8511190524
Download: ML20138S100 (2)

Text

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NOV 0 61985 Dr. David Rossin, Director Nuclear Safety Analysis Center 3412 Hillview Avenue P.O. Box 10412 Palo Alto, California 94303

Subject:

Preliminary Case Study Report -- Effects of Ambient Temperature on Electronic Equipment in Safety Related Instrumentation and Control Systems The Office for Analysis and Evaluation of Operational Data has conducted a study of operational events involving failures of solid state electronic components in safety related instrumentation and control (I&C) systems due to high ambient temperature. The study was initiated by an event that occurred at the McGuire Station on June 4, 1984, which involved the total loss of the control area ventilation system while Unit 1 and Unit 2 were operating at full power.

The enclosed preliminary report documents the review and evaluation of the event at McGuire and of other events involvin Westinghouse pressurized water reactor (PWR) units.gBased similaron failures at operating the review of these events and on the similarity of electronic componcnts used in other types of operating reactor units, the study concludes that the problem of high ambient temperatures affecting electronic components in safety related I&C systems is potentially generic to all operating nuclear units that use heat sensitive electronic components. The study also finds that, in general, plant technical specifications regarding control room / instrument room ventilation systems and instrument system operability are inadequate. The study also finds that certain assumptions in the staff's evaluation of USI-A44 Station Blackout, regarding environmental effects on I&C system equipment could be incorrect. Our preliminary report contains several specific recommendations

• aimed at addressing the concerns raised by the study's findings and conclusions.

The purpose of this letter is to provide you with the opportunity to review the report, particularly with regard to its completeness and accuracy, prior to the issuance of the AE0D final report. Changes to the findings, conclusions, and recomendations will be considered only if the underlying information concerning the details of the plant design, systems operation or sequence of events is in error. Therefore, coments are being solicited on the technical accuracy of the report. The findings, conclusions, and recommendations are provided for your information in order that you understand the significance AEOD places on this issue and therefore obtain a more complete picture of the total report.

s  ! 369 pm

4 Dr. David Rossin We would weltene your comments either informally by phone or formally by letter. Since we wish to finalize and issue the report shortly, we ask that any comments you may wish to make be brought to our attention within 30 days from receipt of this letter.

As you may know, AE0D reports do not represent an official NRC position or the position of the responsible NRC program office. Our reports are one input to an ongoing review and evaluation process, and any recommendation contained in our final report will be considered and perhaps modified or eliminated by the responsible NRC office.

A copy of the preliminary report and this letter are being placed in the Public Document Room at 1717 H Street, N.W., Washington, D.C. 20555.

If you have any questions regarding this matter, please feel free to contact Matthew Chiramal of my staff. Mr. Chiramal can be reached at 301/492 4441.

Sincerely, Original :igned by:

C. J. Helte=es, Jr.

C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data

Enclosure:

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