ML100880412
| ML100880412 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 03/29/2010 |
| From: | Hickey J A, Musser R A NRC/RGN-II |
| To: | |
| References | |
| PNO-II-10-002 | |
| Download: ML100880412 (1) | |
Text
March 29, 2010 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-II-10-002
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 Region II staff (Atlanta, Georgia) on this date.
Facility: Licensee Emergency Classification:
Carolina Power and Li ght Com p an y Notification of Unusual Event H.B. Robinson Steam Electric Plant AlertHarstville
, SC Site Area Emer genc y Dockets/License: 50-261/ DPR-23 General Emer genc y Not A pp licable
SUBJECT:
FIRES AFFECTING SAFETY RELATED EQUIPMENT
On March 28, at 6:51 p.m., H.B. Robinson Steam Electric Plant Unit 2 experienced an automatic reactor trip due to an undervoltage condition on the non-safety related 4kV bus #4 and a subsequent reactor coolant pump trip. At 6:56 p.m. a fire was reported in the non-safety related 4kV bus #5 (which is powered from bus #4).
The licensee's fire brigade responded and the fire in 4kV bus #5 was reported out at 7:05 p.m. Following the reactor trip, at 7:00 p.m., a safety injection occurred due to low pressurizer pressure caused by the post trip cooldown. The plant was stabilized and the licensee initiated an event response team.
At 10:35 p.m. a loud noise and thick smoke in the non-safety 4kV bus #4 room were reported to the control room. At 11:00 p.m. the licensee declared an Alert per Emergency Action Level HA2.1, due to a fire affecting the operability of plant safety systems required to establish or maintain safe shutdown. DC bus grounds were present which affected the safety related buses. The licensee's fire brigade responded and the fire in the bus #4 supply breaker to bus #5 was reported out at 11:01 p.m. The Alert was terminated at 1:34 a.m. after the DC bus grounds were isolated. The NRC resident inspectors responded to the reactor trip and monitored the licensee's actions throughout the subsequent events.
There were no injuries reported due to the fires and they posed no danger to plant workers or the public. The cause of the fires and related electrical issues are still under investigation. Robinson Unit 2 remains shutdown.
NRC fire protection inspectors are currently onsite for a routine inspection and are assisting in the review of the events. Region II will be providing additional inspection resources to evaluate the event and continue monitoring the licensee's actions.
The State of South Carolina has been informed.
Region II received initial notification of this occurrence by telephone from the Resident Inspectors at 7:39 p.m. on March 28. The information presented herein has been discussed with the licensee and is current as of 11:45 a.m., March 29.
ADAMS Accession Number:
CONTACTS:
Randy Musser James Hickey 404-562-4603 843-383-4571 Randy.Musser@nrc.gov James.Hickey@nrc.gov