PNO-III-98-035A, on 980624,reactor Tripped Automatically During Recovery Activities from Tornado Which Damaged Electrical Switchyard & Cut Off Offsite Power Supply

PNO-III-98-035A:on 980624,reactor Tripped Automatically During Recovery Activities from Tornado Which Damaged Electrical Switchyard & Cut Off Offsite Power Supply

ML20199F192
Person / Time
Site:	Davis Besse
Issue date:	06/26/1998
From:	Grobe J, Kozak T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-98-035A, PNO-III-98-35A, NUDOCS 9901210235
Download: ML20199F192 (1)

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, Juns 26, 1998 PRELIMINA.RY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-98-035A 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 Toledo Edison Co. Notification of Unusual Event Davis Besse 1 X Alert Oak Harbor, Ohio Site Area Emergency Dockets: 50-346 General Emergency Not Applicable

Subject:

ALERT DECLARED DUE TO LOSS OF OFFSITE POWER (UPDATE)

(UPDATE) The licensee is continuing its recovery activities from the tornado which damaged the electrical switchyard and cut off the plant's offsite power supply on June 24, 1998. The reactor tripped automatically at 8:43 p.m.

The plant has three 345 kilovolt lines nich supply offsite power to the plant. Aerial surveys on June 25 detertened that two of the lines, the Ohio Edison line and the Lemoyne line, were undamaged. The third line, the Bayshore line, had downed lines and extensive damage to 11 towers.

The plant switchyard had damage to numerous insulators and high voltage connectors. At 7:45 p.m. (ET) on June 25 the Ohio Edison line was connected to the switchyard. Following testing of the 02 Startup Transformer, offsite electrical power was established to plant buses at 8:21 p.m. Both diesel generators were then shut down.

The Lemoyne line was connected to the switchyard at 6:15 a.m. on June 26 and the 01 Startup Transformer was subsequently tested and energized.

Following testing activities, the second offsite power source to the plant was aligned to plant buses at 11:28 a.m.

The licensee downgraded the emergency classification for this event from an Alert to an Unusual Event at 2 a.m. following restoration of one source of offsite power. The licensee established its Joint Public Information Center in Maumee, OH following the Alert and continued its operation until the change in classification to an Unusual Event. At 1:58 p.m., the licensee terminated the Unusual Event.

A Region III (Chicago) inspection team has been monitoring the licensee's recove n activities on an around-the-clock basis. The team includes two inspection supervisors, two operations specialirts, two electrical specialists, four resident inspectors from other sites, and a public affairs officer. Region III has established a restart panel, which includes the onsite team, to further assess the condition of the plant to support restart.

The regional and headquarters staffs have been monitoring plant activities on a 24-hour basis.

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

There continues to be extensive news media interest in the Davis-Besse shutdown with particular emphasis on its effect on electrical power supply in the region. Region III (Chicago) has issued two news releases.

This information is current as of 2 p.m. (ET) on June 26, 1998.

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Contact:

JACK GROBE TOM KOZAK ,o

[ (630)829-9700 (630)829-9866 $7 9901210235 980626 C9 I

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