ML12338A342
| ML12338A342 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 12/03/2012 |
| From: | Ring M A NRC/RGN-III/DRP/B1 |
| To: | |
| References | |
| PNO-III-12-018 | |
| Download: ML12338A342 (1) | |
Text
PRELIMINARY NOTIFICATION - REGION III December 3, 2012 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE
This preliminary notification constitutes EARLY not ice of events of POSSIBLE safety or public interest significance. Some of the information may not yet be fully verified or evaluated by the Region III staff.
Facility Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC
Palo, IA Docket: 50-331 License: DPR-49 Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable
SUBJECT:
UNPLANNED SHUTDOWN EXPECTED TO LAST GREATER THAN 72 HOURS DUE TO ELECTRICAL GROUND DETECTED ON THE MAIN GENERATOR FIELD DESCRIPTION:
On December 1, 2012, at 3:18 p.m. CST, operators of the Duane Arnold Energy Center reactor took the main generator offline, and at 8:15 p.m. CST, shut down the reactor to investigate and repair an electrical ground that was detected on the main generator field.
On Thursday, November 29, 2012, while increasing reactor power following a scheduled refueling outage, control room operators received an alarm for a ground detected on the main generator field. Upon receiving this alarm, operators followed their alarm response procedures and attempted to identify the cause of the alarm while the main generator was online, but were unsuccessful. The licensee proceeded to take the main generator offline to perform additional tests and make repairs. The licensee plans for the reactor to be shut down for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to perform these activities. The NRC resident inspectors observed the shutdown activities, and the State of Iowa has been notified.
This preliminary notification is issued for information only.
Region III received initial notification of this occurrence by a telephone call from the resident inspector's office (RIO) at approximately 7:30 a.m. CST on November 29, 2012. The information presented herein has been discussed with the licensee, and is current as of 11:30 a.m. CST on December 3, 2012.
ADAMS Accession Number ML12338A342.
CONTACT: M. Ring (630) 829-9703 Mark.Ring@nrc.gov