PNO-IV-12-002, B Wolf Creek Nuclear Operating Corp, Update - Plant Startup Following Reactor Trip and Loss of Offsite Power at Wolf Creek Generating Station
| ML12087A337 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 03/27/2012 |
| From: | O'Keefe N, Uselding L Office of Public Affairs Region IV, NRC/RGN-IV/DRP/RPB-B |
| To: | |
| O'Keefe N | |
| References | |
| PNO-IV-12-002B | |
| Download: ML12087A337 (1) | |
March 27, 2012 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-IV-12-002B Facility Licensee Emergency Classification Wolf Creek Nuclear Operating Corp. Notification of Unusual Event Wolf Creek Generating Station Alert Burlington, KS 66839 Site Area Emergency Docket: 50-482 General Emergency License No: NPF-42 X Not Applicable
SUBJECT:
UPDATE - PLANT STARTUP FOLLOWING REACTOR TRIP AND LOSS OF OFFSITE POWER AT WOLF CREEK GENERATING STATION (UPDATE)
DESCRIPTION:
This preliminary notification supplements information in PNO-IV-12-002, which documented that Wolf Creek Generating Station had declared a Notification of Unusual Event following an automatic reactor trip and loss of offsite power on January 13, 2012.
On March 27, 2012, the reactor at Wolf Creek Generating Station was restarted following the completion of repairs to the electrical distribution system.
The unit had been shut down since the event. 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 plants connection to the power grid. The Nuclear Regulatory Commission performed an Augmented Inspection Team (AIT) assessment of the circumstances surrounding the event and will issue a report by April 5, 2012.
The licensee concluded that the cause of the switchyard breaker failure was foreign material internal to the breaker which was present since manufacturing. The damaged breaker and one of the same design were replaced. The licensee concluded that the startup transformer lockout was caused by transformer wiring connections that were not properly insulated. These were repaired. Additionally, the licensee inspected wiring connections on major transformers by the same vendor. NRC resident inspectors monitored licensee activities to restore and repair the electrical distribution system.
The State of Kansas has been informed. This information has been discussed with licensee management. This information is current as of 7:00 a.m. CDT.
This preliminary notification is issued for information only, and will be updated again as more information becomes available.
ADAMS ACCESSION NUMBER: ML12087A337 CONTACTS: Lara Uselding Neil OKeefe (817) 917-0321 (817) 917-5646 Lara.Uselding@nrc.gov Neil.OKeefe@nrc.gov