PNO-III-88-015, on 880302,reactor Tripped Automatically from 93% Power.Caused by Fault in Electrical Distribution Bus Which Provides Power to Reactor Coolant Pumps & Main Feedwater Pumps.Similar Event Occurred on 870710

PNO-III-88-015:on 880302,reactor Tripped Automatically from 93% Power.Caused by Fault in Electrical Distribution Bus Which Provides Power to Reactor Coolant Pumps & Main Feedwater Pumps.Similar Event Occurred on 870710

ML20147G655
Person / Time
Site:	Kewaunee
Issue date:	03/03/1988
From:	Defayette R, Knop R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-88-015, NUDOCS 8803080289
Download: ML20147G655 (1)

PRELIMINA Y NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-III-88-15 Date March 3, 1988 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 Region III staff;on this date.

Facility: Wisconsin Public Service Corp. Licensee Emergency Classification:

Kewaunee- Notification of an Unusual Event Kewaunee, WI 54216 Alert Site Area Emergency General Emergenc.)

Docket No. 50-305 xx Not Applicable Subj:ct: REACTOR TRIP CAUSED 8Y FAULT IN ELECTRICAL SYSTEM At 1:48'p.m. on March 2, 1988, the reactor tripped automatically from 93 percent power as a result of a fault in an electiical distribution bus which provides power to the reactor coolant pumps and main feedwater pump,. All safety systerns functioned as designed during the shutdown. The_ turbine room filled with smoke, but there was no fire. The plant will remain shut down for a 36-day refueling outage which had originally been scheduled to begin March 4. The reactor trip ended a 235-day period of continuous operation.

A similar fault on an electrical bus caused a reactor trip on July 10, 1987. Other electrical distribution bus problems occurred at Kewaunee in January 1980, November 1975, and April 1975.

The licensee is investigating the cause of the bus failure. Region III (Chicago) and the NRC Resident Inspector will monitor the licensee's evaluation and corrective actions.

The State of Wisconsin will be notified.

Region III was notified of this event.about 3:35 p.m., March 2, 1988, by the Headquarters Operation C ter. This ormation is cu en of 1 .m., March 3, 1988.

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CONTACT: R. ayet . . Knop //

FTS 388-5767 "' FTS 388-5547 x DISTRIBUTION:

H. St. NMBB Phillips E/W WFN 1 Chairman Zech KEDU NRR DIX NMSS Com. Roberts ARM 01 Comm. Bernthal ED0 AirRights Mail To:

Com. Carr PA SLITP /;.30 DCS (Original)

Comm. Rogers OGC DOT (Trans. Only)

SECY OGC-H FAX T0: Nicholson Lane Regions CA INPO /t RES Region I GPA NSAC3,f[ Region II

< ACRS Licensee J'O Region IV POR Resident Inspector Region V HQS. Operations Officer / 'D, Region III Rev. November 1987 8803080289 880303

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