ENS 44626
ENS Event | |
|---|---|
12:52 Nov 3, 2008 | |
| Title | Recirc Loop Temperature Element Failed |
| Event Description | On 11/3/08 at 0652 Shutdown Cooling (SDC) was lost on Dresden Unit 3 when the Recirc Loop Temperature Element (3-0260-13B) failed upscale. Unit 3 was in the process of initial cooldown for entry into a refueling outage. Actual Recirc loop temperature was about 217 degrees F based on alternate indications. The temperature element (3-0260-13B) remained upscale for several minutes before returning to its previous value. The failed element was jumpered out and SDC was restarted. This event is reportable under 10CFR 50.72(b)(3)(v)(B).
The licensee notified NRC Resident Inspector. RETRACTION ON 11/18/2008 AT 1214 FROM RANDY WROBLEWSKI TO MARK ABRAMOVITZ * * * On November 8, 2008 shutdown cooling was lost on Dresden Unit 3 when the Reactor Recirculation System Loop Temperature Element (3-0260-13B) failed upscale. Plant operators immediately recognized the condition, and implemented an existing operations procedure to re-establish shutdown cooling flow and ensure that the Shutdown Cooling System continued to fulfill the safety function of residual heat removal. The Shutdown Cooling System is a manually initiated, non-safety related system that is not credited for mitigation of any event or accident in Dresden's safety analyses. The implementation of an existing procedure to restore shutdown cooling system flow in a short period of time (i.e., less than 10 minutes in this case), by the Main Control Room operators trained on the procedure, provides reasonable assurance that the system continued to fulfill its safety function. Therefore, Exelon Generation Company, LLC has determined that this event is not reportable under 10CFR 50.72(b)(3)(v)(B) and is retracting ENS Report 44626. The licensee notified the NRC Resident Inspector. Notified the R3DO (O'Brien). |
| Where | |
|---|---|
Dresden  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+1.85 h0.0771 days <br />0.011 weeks <br />0.00253 months <br />) | |
| Opened: | Thomas Ditchfield 14:43 Nov 3, 2008 |
| NRC Officer: | John Knoke |
| Last Updated: | Nov 18, 2008 |
| 44626 - NRC Website | |
Unit 3 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Shutdown (0 %) |
| After | Hot Shutdown (0 %) |
WEEKMONTHYEARENS 560232022-07-30T03:17:00030 July 2022 03:17:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat RHR Capability Lost Due to Suction Bay Level ENS 480802012-07-10T07:36:00010 July 2012 07:36:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Invalid Group 5 Isolation Due to Failed Test Switch During Surveillance ENS 468572011-05-17T15:30:00017 May 2011 15:30:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Temporary Blockage of Suction Source for Containment Cooling Service Water ENS 454722009-11-02T12:12:0002 November 2009 12:12:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Loss of Shutdown Cooling ENS 446262008-11-03T12:52:0003 November 2008 12:52:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Recirc Loop Temperature Element Failed ENS 444702008-09-07T13:05:0007 September 2008 13:05:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Isolation Condenser Declared Inoperable Following Surveillance Testing ENS 441402008-04-15T12:00:00015 April 2008 12:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection Declared Inoperable ENS 413702005-02-04T01:15:0004 February 2005 01:15:00 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 4160 Volt Relaying and Metering Single Failure Vulnerability ENS 407032004-04-24T15:50:00024 April 2004 15:50:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Isolation Condenser Declared Inoperable 2022-07-30T03:17:00 | |