ML111180005
| ML111180005 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/27/2011 |
| From: | Jones W B NRC/RGN-II |
| To: | Tennessee Valley Authority |
| References | |
| PNO-II-11-003 | |
| Download: ML111180005 (1) | |
Text
April 27, 2011 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-II-11-003 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 At 6:21 PM 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 PM 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, which was due to damage from storms and a tornado moving through the area, caused all three units to automatically shut down due to a loss of offsite power. Seven of the plant's eight back-up diesel generators started and powered emergency busses. One diesel was out of service for maintenance at the start of the event.
All three units are in a stable condition in Mode 3, hot shutdown. Units 1 and 3 are controlling pressure using High Pressure Coolant Injection (HPCI) and controlling level with Reactor Core Isolation Cooling (RCIC). Suppression pool cooling has been established to maintain suppression pool temperature. Unit 2 has restored one train of the condensate and feed system and is cooling down using main steam bypasses. There have been no radioactive releases above regulatory limits.
Region II received initial telephone notification of this occurrence from the licensee. NRC inspectors are onsite monitoring the activities. The information presented herein has been discussed with the licensee and State officials and is current as of 10:00 PM EDT.
CONTACT: William Jones 404 997-4501