PNO-III-97-065, on 970805,Westinghouse Circuit Breaker Failed to Open on Demand During Planned Change of Pumps in RHR Sys. RHR Sys Provides Reactor Cooling While Plant Shut Down.Nrc Augmented Insp Team Dispatched to Plant to Review Breaker
| ML20151L005 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 08/05/1997 |
| From: | Gardner R, Wright G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| References | |
| PNO-III-97-065, PNO-III-97-65, NUDOCS 9708060207 | |
| Download: ML20151L005 (2) | |
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, August
- 5. 1997 i
I PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-97-065 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 Region III staff (Lisle. Illinois) on this date.
Facility Licensee Emergency Classification Illinois Power Co.
Notification of Unusual Event Clinton 1 Alert Clinton. Illinois Site Area Emergency Dockets: 50-461 General Emergency X Not Applicable
Subject:
AUGMENTED INSPECTION TEAM TO REVIEW 4160 VOLT CIRCUIT BREAKER FAILURE At approximately 4 a.m. on August 5. 1997, a 4,160 volt Westinghouse circuit breaker failed to open on demand during the planned change of pumps in the residual heat removal (RHR) system. The licensee was shifting from the 'A' RHR pump to the 'B' RHR pump, and the 'A' pump circuit breaker should have opened to interrupt power to the pump. The RHR system provides reactor cooling while the plant is. shut down.
As a result of this failure and an earlier circuit breaker failure, the licensee declared all safety-related 4,160 volt Westinghouse circuit breakers inoperable.
The. licensee had planned to begin starting up the unit, which has been shut down since September 5.1996. The circuit breaker failure has l
delayed the planned startup.
A similar circuit breaker failed to open on July 22. This circuit breaker was supplying power from an auxiliary transformer to the Division 1 electrical bus. The licensee believes this earlier failure was due to the i
breaker not closing fully. It is believed that the breaker had closed sufficiently to make electrical contact but not enough to fully charge the springs which are used to open the circuit breaker.
The cause of the most recent failure is not yet known. The licensee is assembling an independent team of outside consultants to evaluate the failure.
An NRC Augmented Inspection Team (AIT) has been dispatched to the plant to review the circuit breaker problems and monitor the licensee's investigation.
During the current outage the licensee inspected and tested all safety-related 4,160 volt Westinghouse circuit breakers. About 26 such breakers are in the plant. The licensee also inspected and performed j
maintenance on other types of circuit breakers.
Region III will issue a news release on the AIT inspection. An exit i
meeting, open to public observation, will be held at the completion of I-the inspection.
9708060207 970305 S
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PDR I&E PNO-III-97-065 PDR 060103
, PNO-III-97-065 -
The State of Illinois has been notified. The information in this areliminary notification has been reviewed with licensee management.
Region III was notified of the circuit breaker failure by the licensee and Senior Resident Inspector at about 7:45 a.m. on August 5, 1997. This information is current as of 2:30 p.m. on August 5, 1997.
Contact:
GEOFF WRIGHT RON GARDNER (630)829-9602 (630)829-9751
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