ML120180157
| ML120180157 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 01/18/2012 |
| From: | O'Keefe N F, Uselding L M NRC Region 4 |
| To: | |
| References | |
| PNO-IV-12-002 | |
| Download: ML120180157 (2) | |
Text
January 18, 2012 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE
-- PNO-IV-12-002 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 Wolf Creek Nuclear Operating Corp.. Wolf Creek Generating Station Burlington, KS 66839
Docket: 50-482 License No: NPF-42 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable
SUBJECT:
WOLF CREEK GENERATING STATION NOTIFICATION OF UNUSUAL EVENT DESCRIPTION:
On January 13, 2012, Wolf Creek Generating Station declared a Notice of Unusual Event (NOUE) at 2:15 p.m. CST following an automatic reactor trip and loss of offsite power that occurred at 2:03 p.m. CST. The failure of a main generator output breaker, followed by an unexplained loss of power to the startup transformer, caused the switchyard to be de-energized, which removed the plant's connection to the power grid. All safety systems responded as expected, and emergency diesel generators automatically powered safety-related equipment.
At 5:09 p.m. on January 13, Wolf Creek terminated the NOUE after offsite power was partially restored. Plant personnel are continuing to investigate the cause of the failure and determine necessary repairs. The plant is in a safe condition and has been brought to the cold shutdown operating mode, with offsite power supplying safety-related loads and select non-vital loads and the emergency diesel generators secured. The licensee restored power to most of the plant systems on January 17 after verifying that the non-vital switchboards were safe to energize. There were no radiological releases due to this event.
The NRC resident inspectors responded to the control room to monitor site activities during the event. They were onsite during the weekend to monitor plant cooldown activities and the initial recovery actions.
Additional NRC inspection follow-up is planned to assess the circumstances surrounding the event and some unexpected conditions during and following the NOUE, including a small essential service water leak inside containment, a ground alarm on emergency diesel generator B, a trip of the turbine-driven auxiliary feedwater pump after 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of operation, and a failure of the temporary diesel-driven fire pump. Inspectors will also review the impact on operations of not having power to non-vital loads for a prolonged period of time.
The State of Kansas has been informed. This information has been discussed with licensee management and is current as of 7:00 a.m. CST.
This preliminary notification is issued for information only, and will be updated as more information becomes available.
PN-IV-12-002 ADAMS ACCESSION NUMBER: ML120180157
CONTACTS: Lara Uselding Neil O'Keefe (817)917-0321 (817)917-5646 Lara.Uselding@nrc.gov Neil.OKeefe@nrc.gov