ML111190004
| ML111190004 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/28/2011 |
| From: | Moorman J H NRC/RGN-II |
| To: | Tennessee Valley Authority |
| References | |
| PNO-II-11-003A | |
| Download: ML111190004 (1) | |
Text
April 28, 2011 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-II-11-003A 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 Region II staff (Atlanta, Georgia) on this date.
Facilit y: Licensee Emergency Classification:
Tennessee Valle y Authorit y Notification of Unusual Event Browns Ferr y Units 1 , 2 , and 3Alert Site Area Emer genc y Docket Numbers: 50-259, 260 and 50-296 License Numbers: DPR- 33, DPR-52 and DPR-68 General Emer genc y Not A pp licable
SUBJECT:
NOTIFICATION OF UNUSUAL EVENT DUE TO LOSS OF OFFSITE POWER (UPDATE)
At 6:21 p.m. EDT, on April 27, 2011, NRC entered the Monitoring Mode due to the Browns Ferry Nuclear Plant declaring a Notification of Unusual Event at 6:01 p.m. EDT. The emergency was declared due to a loss of normal and alternate supply voltage to all 4KV shutdown boards for greater than 15 minutes and at least two Diesel Generators supplying power to 4KV shutdown boards. The loss of AC power was due to damage from storms and a tornado moving through the area. All three units automatically shut down with no complications. Seven of the plant's eight back-up diesel generators started and powered emergency busses and are currently operating. The diesel that did not start was out of service for maintenance and is still undergoing maintenance.
TVA has placed all three units in Mode 4, cold shutdown. There is one source of offsite power available to the site. TVA's efforts to restore a second source of offsite power are continuing and are expected to take 2-3 days to complete. There have been no radioactive releases above regulatory limits.
The Region II Incident Response Center is staffed and in Monitoring Mode. NRC inspectors are onsite monitoring the activities. The information presented herein has been discussed with the licensee and is current as of 3:30 p.m. EDT.
CONTACT: Jim Moorman 404-997-4200