05000317/LER-1981-061-03, /03L-0:on 810803,operator Discovered Plant Computer Had Failed,Rendering Incore Detector Sys Inoperable.Caused by Computer Stopping on Rapid Access Disk Transmission Error,Possibly Due to High Room Temp

/03L-0:on 810803,operator Discovered Plant Computer Had Failed,Rendering Incore Detector Sys Inoperable.Caused by Computer Stopping on Rapid Access Disk Transmission Error,Possibly Due to High Room Temp

ML20010F676
Person / Time
Site:	Calvert Cliffs
Issue date:	09/01/1981
From:	Lagiewski J, Rizzo P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20010F673	List: 05000317/LER-1981-061, Forwards LER 81-061/03L-0 05000317/LER-1981-061-03, /03L-0:on 810803,operator Discovered Plant Computer Had Failed,Rendering Incore Detector Sys Inoperable.Caused by Computer Stopping on Rapid Access Disk Transmission Error,Possibly Due to High Room Temp
References
LER-81-061-03L, LER-81-61-3L, NUDOCS 8109110146
Download: ML20010F676 (2)

LER-1981-061, /03L-0:on 810803,operator Discovered Plant Computer Had Failed,Rendering Incore Detector Sys Inoperable.Caused by Computer Stopping on Rapid Access Disk Transmission Error,Possibly Due to High Room Temp

Event date:
Report date:
3171981061R03 - NRC Website

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/4 15 REFORT D ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h El1J L At 1615, during normal operation, the Control Room Operator discovered I

i o 13 i j that the plant computer had failed, rendering the incore detector sy3-l In iai j ten inocerable (T.S. 3.3.3.2).

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lOls,I at 1803. The excore detector systen remained operable during this l

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40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h li;o l l The Westinahouse P-250 computer stooned uoon a Ranid Access Disk (RAD) l lTTT~l I transmission error. Suspect high ambient room temnerature caused inter-I gi mittent narginal RAD circuit operation. No failed ccmnonent was found.

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DPR-53 EVENT DATE 03-03-81 REPORT DATE 09-01-31 ATTACHMENT CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (CONT'D)

The Westinghouse P-250 computer was found stopped after a Rapid Access Disk (RAD) transmission error. Immediate efforts to restart the computer using bootstrap procedures were futile. Doors to the RAD and other cabinets were opened for troubleshooting purposes. Af ter approximately ten minuties, the computer was bootstrapped successfully. It is suspected that seasonal high ambient room temperatures caused marginal RAD circuit operation resulting in the computer's inability to read or write stored data. No hardware nor software problems were detected.

In the summer season computer room temperature increases during periods of high outside air temperature. Room temperature reached approximately 85 degrees Fahrenheit on the date of the event. It is believed that this temperature affected the RAD operation. Since the fault symptom is intermittent, future action depends on the opportunity to troubleshoot the problem should the symptom return or a marginal circuit fail.