ENS 47805
ENS Event | |
|---|---|
00:03 Apr 5, 2012 | |
| Title | Notice of Unusual Event Due to Dual Unit Loss of Offsite Power |
| Event Description | At 2003 EDT on 4/4/12 Catawba Unit 1 automatically tripped due to a loss of offsite power. The licensee declared a Notice of Unusual Event due to entry into EAL 4.5.U.1, 'AC Electrical Power from All Offsite Sources Has Been Lost for Greater Than 15 Minutes.' Power is still available from onsite sources. All four Emergency Diesel Generators [EDG] started and powered their respective safety buses.
The EAL poses no threat to the safety of the public. The Unit 1 control rods fully inserted, there is no known primary to secondary leakage, and the auxiliary feedwater water system automatically started. The licensee notified the NRC Resident Inspector Notified: DHS SWO, FEMA, DHS NICC, USDA, HHS, DOE, EPA, and Nuclear SSA via email.
Catawba Nuclear Generating Station exited the Unusual Event at 0137 EDT after restoring offsite power at 0135 EDT to the Unit 1A and Unit 2B essential busses. The EDGs powering these busses have been secured and returned to Standby. The Unit 1B and Unit 2A essential busses remain energized by their respective EDGs. The licensee does not have an estimate as to when offsite power will be restored for these busses. Additional information provided as follow-up includes: 4-hour notification per 10CFR50.72(b)(2)(iv)(B) due to the Unit 1 Reactor Protection System [RPS] actuation (Rx Trip), 4-hour notification per 10CFR50.72(b)(2)(xi) for offsite notifications to the States of North and South Carolina and the counties of York, Gaston and Mecklenburg, 8-hour notification per 10CFR50.72(b)(3)iv)(A) due to the Unit 1 Rx Trip, Unit 1 Auxiliary Feedwater automatic start, Unit 1A and 1B and Unit 2A and 2B EDG auto starts. 8-hour notification per 10CFR50.72(b)(3)(v)(B) due to the loss of Residual Heat Removal [RHR] cooling on the initial loss of power. Unit 2 RHR was restored in less than three (3) minutes when the essential busses were re-energized by the EDGs. The licensee informed the NRC Resident Inspector. Notified R2IRC, EO (Nelson), IRD (Gott) and FEDS (DHS SWO, DOE Ops Center, FEMA, HHS Ops Center, DHS NICC, USDA Ops Center, EPA EOC) and NuclearSSA via email. |
| Where | |
|---|---|
Catawba  South Carolina (NRC Region 2) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration | |
| Time - Person (Reporting Time:+-3.63 h-0.151 days <br />-0.0216 weeks <br />-0.00497 months <br />) | |
| Opened: | Don Wisniewski 20:25 Apr 4, 2012 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Apr 5, 2012 |
| 47805 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 478052012-04-05T00:03:0005 April 2012 00:03:00
[Table view]10 CFR 50.72(a)(1)(i), Emergency Class Declaration Notice of Unusual Event Due to Dual Unit Loss of Offsite Power ENS 430662006-12-27T17:37:00027 December 2006 17:37:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Declared Unusual Event Due to Unidentified Reactor Coolant Leakage Greater than Tech Spec Limit ENS 425922006-05-20T18:21:00020 May 2006 18:21:00 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event - Reactor Trip of Both Units Due to Loss of All Offsite Power 2012-04-05T00:03:00 | |