PNO-III-97-065A, on 970805,Westinghouse Circuit Breaker Failed to Open Signal During Planned Switch of Pumps in RHR Sys Update Made.Licensee Investigation Attributed Failure to Lack of Appropriate Maint

PNO-III-97-065A:on 970805,Westinghouse Circuit Breaker Failed to Open Signal During Planned Switch of Pumps in RHR Sys Update Made.Licensee Investigation Attributed Failure to Lack of Appropriate Maint

ML20210K030
Person / Time
Site:	Clinton
Issue date:	08/15/1997
From:	Gardner R, Wright G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-97-065A, PNO-III-97-65A, NUDOCS 9708190118
Download: ML20210K030 (1)

August 15, 1997 PREllMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-97-065A 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 (UPDATE)

On August 5, 1997, a 4,160 volt Westinghouse circuit breaker failed to open upon signal during the planned switch of pumps in the residual heat removal (RHR) system. At the time of the incident, the unit was being prepared for startup after a refueling and maintenance outage which began September 5, 1996.

The licensee's investigation has attributed the failure to the lack of appropriate maintenance and lubrication of circuit breaker components, As a result the spring forces which open the breaker were insufficient.

There were no problems found with the latching und control components of the breaker.

Because of these findings, the licensee is planning to perform maintenance on all 4.160 volt and 6,900 volt Westinghouse circuit breakers. About 70 circuit breakers in both safety-related and non-safety-related systems will be involved. This maintenance will involve inspecting, cleaning, lubricating, and testing each breaker. The work will be done onsite and, in some cases, offsite.

These corrective actions are expected to exterd the current outage for several weeks.

The NRC Augmented Inspection Team (AIT) has performed an independent review of the circumstances surrounding the circuit breaker failure. The team will hold its exit meeting with the licensee on August 20. This meeting will be open to public observation.

Region III (Chicago) issued a news announcement on the AIT review and has continued to respond to news media inquiries.

The State of Illinois will be notified of this updated information. The information in this preliminary notification has been reviewed with licensee management.

This information is current as of 1 p.m. on August 15, 1997.

Contact:

GEOFF WRIGHT RON GARDNER

\\

(630)829-9602 (630)829-9751 6

81 18 970815

()

PNO-III-97-065 PDR

.u.

-