ENS Event | |
|---|---|
18:21 May 20, 2006 | |
| Title | Unusual Event - Reactor Trip of Both Units Due to Loss of All Offsite Power |
| Event Description | The licensee experienced a reactor trip to Units 1 & 2 due to loss of all offsite power. This anomaly was believed to be from an overcurrent condition in a relay, and limited to the Catawba switchyard. The reactor tripped due to actuation of the reactor protection system (RPS), and all rods for both Units fully inserted as designed. The Unit 1 Pressurizer PORV did lift momentarily. The decay heat is being released through the secondary PORV's, and steam generator level is being maintained with the auxiliary feedwater system (AFW). Presently, Units 1 & 2 are in EAL 4.5.U.1 (Loss of Offsite Power to Essential Busses for greater than 15 minutes). The licensee indicated there are no steam generator tube leaks in either unit. The licensee activated the TSC at 15:50 EDT.
The licensee notified the NRC Resident Inspector, as well as State and local government.
The licensee terminated from the Unusual Event at 0140 EDT on 5/21/06 based on restoration of offsite power to all essential buses. The licensee is no longer in a Tech Spec cooldown LCO and both units have secured from further cooldown and have stabilized conditions in Mode 3. Both units are still on natural circulation with AFW cooling and decay heat removal through secondary PORVs. The licensee will notify the NRC Resident Inspector. R2DO (Widmann), NRR (Ross-Lee), IRD (Blount), FEMA (Kimbrell) and DHS(York) have been notified |
| 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:+-2.1 h-0.0875 days <br />-0.0125 weeks <br />-0.00288 months <br />) | |
| Opened: | Larry Long 16:15 May 20, 2006 |
| NRC Officer: | John Knoke |
| Last Updated: | May 21, 2006 |
| 42592 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (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 | |