ENS Event | |
|---|---|
03:21 Aug 28, 2011 | |
| Title | Shutdown Cooling Temporarily Isolated |
| Event Description | In accordance with 10 CFR 50.72 (b)(3)(v)(B) this event notification is being made to report an event that could have prevented the fulfillment of the safety function to remove residual heat. On August 27, 2011, following refueling, the plant was shutdown in Mode 4 with reactor coolant temperature being maintained 100-120 degrees F. Reactor coolant temperature was being controlled with RHR B operating in the Shutdown Cooling mode. At 2021 [EDT], an equipment failure caused a loss of Reactor Protection System (RPS) B resulting in a closure of RHR-V-9 (RHR Shutdown Cooling Inboard Isolation Valve), interrupting shutdown cooling flow. Operators transferred RPS B to the alternate power supply and restored RHR B to shutdown cooling. Shutdown cooling was out of service for 34 minutes.
During the 34 minute interruption of shutdown cooling, reactor coolant temperature rose from 107 degrees F to 111 degrees F. Following restoration of shutdown cooling, reactor coolant temperature was restored. All containment isolations resulting from the loss of RPS B occurred as expected. Further investigation is ongoing to determine the cause of the equipment failure that caused the loss of RPS B. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Columbia  Washington (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+-0.67 h-0.0279 days <br />-0.00399 weeks <br />-9.17766e-4 months <br />) | |
| Opened: | Michael Stodick 02:41 Aug 28, 2011 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Aug 28, 2011 |
| 47209 - NRC Website
Loading map... | |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 569282024-01-18T20:04:00018 January 2024 20:04:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Residual Heat Removal Degraded Due to Service Water Leakage ENS 472092011-08-28T03:21:00028 August 2011 03:21:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Shutdown Cooling Temporarily Isolated ENS 429612006-11-03T11:09:0003 November 2006 11:09:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Procedural Error Caused Residual Heat Removal Shutdown Cooling Inboard Containment Isolation Valve to Close. 2024-01-18T20:04:00 | |