PNO-IV-93-023, on 930810,reactor Scram Occurred Due to MSIVs Going Closed.Licensee Initiated Task Team to Review Event & Develop Action Plan to Address Turbine Control Problems. State of Louisiana Informed

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PNO-IV-93-023:on 930810,reactor Scram Occurred Due to MSIVs Going Closed.Licensee Initiated Task Team to Review Event & Develop Action Plan to Address Turbine Control Problems. State of Louisiana Informed
ML20056D822
Person / Time
Site: River Bend Entergy icon.png
Issue date: 08/12/1993
From: Gagliardo G
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-93-023, PNO-IV-93-23, NUDOCS 9308180090
Download: ML20056D822 (2)


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August 12, 1993 i

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-93-023 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 IV staff on this date.

Facility Licensee Emergency Classification Gulf States Utilities Co. Notification of Unusual Event River Bend 1 Alert St Francisville, Louisiana Site Area Emergency Dockets: 50-458 General Emergency X Not Applicable

Subject:

FORCED OUTAGE TO EXCEED 72 HOURS On August 10, 1993, at approximv Q:49 p.m. (CDT), a reactor SCRAM occurred because of the main s .m ~1ation valves going closed. The plant was being returned to full per operation following a 17-day forced outage to repair a feedwater stop valve. The forced outage ended on July 30, 1993.

At the time of the event, the plant was holding at 75 percent power to conduct troubleshooting activities on the main turbine pressure control system. The licensee has been experiencing turbine control problems over l the last several months. Previous efforts to resolve the problems, including transmitter change out, had not been successful. During the conduct of the troubleshooting activity, an instrumentation and control technician inadvertently shorted two terminals together, resulting in a high pressure signal. The bypass valves opened, causing reactor pressure to decrease rapidly (approximately 3 seconds). The main steam isolation valves closed as expected on low pressure. The plant responded as expected to the transient.

The licensee has initiated a task team to review the event and develop an action plan to address the turbine control problems. The turbine and control valve vendors will be providing onsite technical support to the licensee. The present restart schedule is Mode 2 operation on August 16

, and generator synchronization and full power operation on August 18 and i 21, respectively.

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The state of Louisiana will be informed.

Region IV. received notification of this occurrence by telephone from a Region IV inspector providing site coverage at 9:30 a. m. (CDT). Region l IV has informed EDO, NRR, and PA.

This information has been confirmed with a licensee representative.

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Contact:

G. Gagliardo (817)860-8270 a

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