ML20012B030
| ML20012B030 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 03/05/1990 |
| From: | Johnson W, Joel Wiebe NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| References | |
| PNO-ADSP-90-005, PNO-ADSP-90-5, NUDOCS 9003130313 | |
| Download: ML20012B030 (2) | |
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March 5, 1990 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-ADSP-90-05 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the ADSP staff on this date.
FACILITY: TV Electric Licensee Emergency Classification:
Comanche Peak Unit 1 Notificatian of Unusual Event Docket No. 50-445 Alert Glen Rose, Texas Site Area Emergency General Emergency X
Not Applicable 4
SUBJECT:
REACTOR TRIP WHILE SHUT DOWN At 1:M a m. (CST) on March 5,1990, the unit was in Mode 5 at 155' and 380 psig with four RCPs ant the Train A RHR pump operating. While pulling a control rod shutdown bank for drop time testing a reactor trip occurred.
The trip was caused by loss of' power to an intermediate range instrument when Inverter IPC1 failed, resulting-in a high flux trip. When the inverter bypass power supply breaker was closed at 1:57 a.m., spikes in source range and RCS pressure instruments--
caused a flux doubling actuation and initiated closure of the RCS to RHR suction. valve. The operators secured the Train A RHR pump and shif ted the lineup to put Train B RHR in service. This lineup change was completed in-
. approximately 30 minutes.. During this time, RCS temperature increased to 180'F due to the heat added by the four operating RCPs.
(There is no decay heat since initial criticality has not been achieved.) A similar inverter failure occurred on February 9, 1990 during initial fuel load. The licensee is investigating the cause of the inverter failure, the apparent lack of complete information from the sequence of events recorder, the apparent failure to get an alarm on intermediate range high flux, the need to revise procedures for reenergizing equipment after an inverter failure, and the coordination of the time base of various computers.
Local media interest has not been expressed. Neither the licensee nor the NRC plan to issue a news release.
The State of' Texas will be informed.
The Comanche Peak Project Division received initial notification of this occurrence by telephone to'the SRI from the licensee on March 5,1990. The information presented herein has been discussed with the licensee and is current as of 9:30a.m.(CST)onMarch5,1990.
CONTACT:
J. S. Wiebe 817 897-1500 W.-D. Johnson 817 897-1500
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. PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-ADSP-90-05 i
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