PNO-III-97-053, on 970602,Unit 1 Experienced Automatic Reactor Trip from 100% Power,Due to Electrical Failure in One of Three Control Rod Control Cabinets.All Safety Sys Functioned as Designed & Reactor Stabilized in Hot Shutdown

PNO-III-97-053:on 970602,Unit 1 Experienced Automatic Reactor Trip from 100% Power,Due to Electrical Failure in One of Three Control Rod Control Cabinets.All Safety Sys Functioned as Designed & Reactor Stabilized in Hot Shutdown

ML20140A882
Person / Time
Site:	Prairie Island
Issue date:	06/04/1997
From:	Michael Kunowski, Mccormickbarg NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-97-053, PNO-III-97-53, NUDOCS 9706050073
Download: ML20140A882 (1)

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June 4, 1997 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-97-053 l

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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 Northern States Power Co. l Notification of Unusual Event  :

Prairie Island 1 Alert i Welch, Minnesota Site Area Emergency Dockets: 50-282 General Emergency l X Not Applicable

Subject:

SHUTDOWN TO REPAIR GROUND FAULT IN CONTROL ROD DRIVE SYSTEM On June 2,1997. Unit 1 experienced an automatic reactor trip from 100 percent power due to an electrical failure in one of the three control

! rod control cabinets. All safety systems functioned as designed and the reactor was stabilized in Hot Shutdown while troubleshooting of the  !

j failure began. -

On June 3. the licensee's troubleshooting narrowed the source of the electrical problem to either a section of cable inside containment from the reactor missile shield to the drive mechanism for control rod H-8 or i in the gripper coil of the drive mechanism itself. '

The reactor will be taken to Cold Shutdown to isolate and repair the problem. The shutdown to repair the problem is expected to take approximately 5 to 7 days.

The State of Minnesota will be informed. The i, ,3rmation in this preliminary notification has been reviewed with licensee management.

The licensee notified the NRC Operations Center of this event at 11:55 a.m. (CDT) on June 2.1997. This information is current as of 10:45 a.m.

(CDT) on June 4. 1997.

Contact:

JAMES MCCORMICK-BARG MICHAEL KUNOWSKI (630)829-9618 (630)829-9618 i i I

V 9706050073 970604 \

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