ML20215E875
| ML20215E875 | |
| Person / Time | |
|---|---|
| Issue date: | 12/05/1986 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20215E878 | List: |
| References | |
| REF-GTECI-A-44, REF-GTECI-EL, TASK-A-44, TASK-OR IEIN-85-089, IEIN-85-89, NUDOCS 8612230152 | |
| Download: ML20215E875 (2) | |
Text
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,_' December 5, 1986 AE0D/C604 MEMORANDUM FOR: Harold R. Denton, Director Office of Nuclear Reactor Regulation FROM: C. J. Heltemes, Jr., Director Office .for Analysis and Evaluation of Operational Data
SUBJECT:
CASE STUDY REPORT--EFFECTS OF AMBIENT TEMPERATURE ON ELECTRONIC COMP 0NENTS IN SAFETY-RELATED INSTRUMENTATION AND CONTROL SYSTEMS-The Office for Analysis and Evaluation of Operational Data (AE0D) has finalized its' case study on the effects of ambient temperature on electronic components in safety-related instrumentation and control systems. The final report addresses the peer review comments provided by NRR, IE, the Regions, INP0, NSAC, Westinghouse Electric Corporation and Duke Power Company. The final report also includes the analysis and evaluation of three additional operational experiences not included in the preliminary report involving failures of electronic components due to elevated temperature. We have enclosed a copy of our final report for your information and appropriate action.
The study was initiated by an event that occurred at the McGuire Station in June 1984, during which the plant's control area ventilation system was lost for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. Based on this event, and the resulting initial AE0D study, Information Notice 85-89 " Potential loss of Solid-State Instrumentation Following Failure of Control Room Cooling" was issued to alert licensees of operating nuclear plants of the event and the NRC's concerns. Three other events were subsequently identified in which the root cause of failure of the instrumentation system was determined to be overheating of electronic components located in cabinets in a controlled environmental area. The enclosed report documents the review and evaluation of these four events.
Overheating of electronic components in safety-related instrumentation and control systems raises two concerns: (1) decreased reliability of electronic equipment due to increased failure rate of heat sensitive electronic components, and (2) the potential for common cause failure of redundant instrument channels due to extended loss of normal cooling to the cabinets in which the instruments are located. The enclosed case study report contains specific recommendations which, based on the study's findings and conclusions, address these two concerns. The recommendations pertain to: (1) the establish-ment of plant procedures and training of operators to cope with loss of cooling to instrument cabinets, (2) the need to monitor actual environmental conditions
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a Harold R. Denton (specifically, temperature) in instrument cabinets, (3) plant technical specification requirements governing the operability of control room cooling and ventilation systems to reflect the actual operating temperatur in the instrument cabinets, and (4) specific considerations in the plant-specific evaluation and resolution of the station blackout issue (USI A-44).
It.is requested that NRR give appropriate consideration to implementation of these recommendations. However, in view of the common NRC and industry objective of resolving identified safety issues relating to the operation of nuclear plants in the most effective manner, those recommendations dealing with procedures, training and hardware modifications could be turned over to an appropriate industry group for consideration and follow-up action.
If you have any questions regarding the enclosed report, please contact Matthew Chiramal of my staff. Mr. Chiramal can be reached at 492-4441.
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C. J. Heltemes, Jr. , Director Office for Analysis and Evaluation of Operational Data Enclosure As Stated cc w/ enclosure:
D. Humenansky, OCM V. Stello, ED0 W. Russell J. Sniezek, EDO K. Kniel J. Roe, ED0 A. Rubin F. Rosa D. Thatcher R. Karsch D. Hood J. Hayes A. DeAgazio E. Licitra J. Hopkins DISTRIBUTION:
EPDRa AEOD CF AE00 SF ROAB CF ROAB S/R (conc.)
MChiramal SRubin WLanning KBlack MWilliams FHebdon CHeltemes 0FC :SC:R0AB y : BC:R0AB : DD:AE0D : D:AEOD : : :
NAME :MChiramal:as SRubin : FHe don : CH mes : : : :
DATE:12/3/86 . : 12/i/86 : 12/4 /86 : 12/ /86 : : : ]