PNO-IV-03-023, A: Entergy Operations, Inc., Grand Gulf Nuclear Station, Shutdown of Greater than 72 Hours (Update)
| ML031210443 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/01/2003 |
| From: | Hoeg T, Johnson W NRC/RGN-IV/DRP |
| To: | |
| References | |
| PNO-IV-03-023A | |
| Download: ML031210443 (1) | |
May 1, 2003 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-03-023A 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 Entergy Operations, Inc. Notification of Unusual Event Grand Gulf Nuclear Station Alert Docket: 50-416 License: NPF-29 Site Area Emergency General Emergency X Not Applicable
SUBJECT:
SHUTDOWN OF GREATER THAN 72 HOURS (UPDATE)
DESCRIPTION: At 9:47 a.m. (CDT) on April 24, 2003, Grand Gulf Nuclear Station (GGNS) experienced an automatic reactor scram following a loss of the west switchyard bus and a momentary interruption of offsite power to the east switchyard bus.
In addition to the loss of the west bus in the switchyard following the failure of the disconnect switch locking device, offsite power feeds to the east bus were tripped as a result of the fault. When the east bus was deenergized following the main generator trip, it was automatically repowered from the offsite sources. The east bus was deenergized for about one second. The Division 1, 2, and 3 emergency diesel generators responded properly. Throughout the event, a source of 115 kV power was available to be supplied to the safety-related busses. The loss of the nonsafety-related buses resulted in the loss of the instrument air compressors and feedwater, condensate, and reactor recirculation pumps.
Instrument air was restored after about 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
Following repairs to the turbine electrohydraulic control system, an intermediate range neutron monitor, and a drywell sump pump, the reactor reached Mode 1 during the evening of April 28, 2003. Following additional repairs to the turbine electrohydraulic control system, the turbine was synchronized to the grid on April 30, 2003.
The NRC plans to initiate a special inspection on May 5, 2003, to better understand the cause of the automatic scram, system and component responses, and personnel actions following the event.
The state of Mississippi will be informed.
Region IV received notification of this occurrence from the resident staff on April 30, 2003. Region IV has informed the EDO/NRR/PA.
This information has been discussed with the licensee and is current as of 3 p.m. on April 30, 2003.
CONTACTS: W. Johnson at 817-860-8148 T. Hoeg at 601-437-4620