ENS 40245
ENS Event | |
|---|---|
08:04 Oct 14, 2003 | |
| Title | Unusual Event Declared - Loss of Shutdown Cooling |
| Event Description | At 0404 EDT on 10/14/03, Millstone 2 lost shutdown cooling due to the loss of power to vital power bus VA10. Power and shutdown cooling were restored at 0414. Millstone declared an Unusual Event at 0423 due to a greater than 10 degree increase in reactor coolant system temperature. Reactor coolant system temperature increased from 101 degrees to 113 degrees.
Power was lost to VA10 while attempting to swap power supplies from inverter 1 to inverter 5. Inverter 1 is now supplying power to VA10. The licensee notified the NRC Resident Inspector.
Millstone 2 exited their Unusual Event at 0532, after completing the abnormal operating procedure and stabilizing plant conditions. Notified R1DO (Bellamy), NRR (Reis), DIRO (McGinty), DHS (Rick DaSilva), and FEMA (David Barden)..
An update to event notification 40245 is being made to reflect that the loss of shutdown cooling is also considered reportable under 10CFR50.72(b)(3)(v). Additionally, further review of plant response following the loss of VA10, indicates that due to an equipment performance issue (failed relay) the containment isolation valves did not respond as expected and were manually closed per procedure. This issue will be investigated and addressed as needed in the LER. The NRC Resident Inspector will be notified Reg1 RDO(McDermott) was notified. |
| Where | |
|---|---|
Millstone  Connecticut (NRC Region 1) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| LER: | 05000336/LER-2003-005 |
| Time - Person (Reporting Time:+-2.87 h-0.12 days <br />-0.0171 weeks <br />-0.00393 months <br />) | |
| Opened: | Jeff Young 05:12 Oct 14, 2003 |
| NRC Officer: | Bill Gott |
| Last Updated: | Oct 14, 2003 |
| 40245 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |