ENS 45071
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ENS Event | |
|---|---|
09:19 May 15, 2009 | |
| Title | Group 1 Isolation of All Main Steam Valves While Performing a Special Procedure |
| Event Description | At 0519 on 5/15/09, a Group 1 isolation signal was received which resulted in all eight Main Steam Isolation Valves closing. The signal was received based upon a valid main condenser low vacuum signal coincident with reactor mode switch placed in RUN position. The isolation was an unanticipated result of a special purpose procedure which was being performed as a functional test for maintenance work that had been performed on intermediate range nuclear instrumentation. The procedure had installed jumpers to bypass the Group 1 isolation for Mode Switch in Run, but did not account for low condenser vacuum isolation. The low condenser vacuum switches were in the bypass position, but this logic does not prevent Group 1 isolation in the Run mode. The Group 1 isolation was completed successfully with all MSIVs and small bore valves closing as designed. MSIV closure with Mode Switch in Run position also caused a RPS actuation / full scram. The reactor was subcritical and all control rods were already fully inserted as the reactor was being maintained in Cold Shutdown.
The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Hatch  Georgia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+0.9 h0.0375 days <br />0.00536 weeks <br />0.00123 months <br />) | |
| Opened: | Edwen Urquhart 10:13 May 15, 2009 |
| NRC Officer: | Bill Huffman |
| Last Updated: | May 15, 2009 |
| 45071 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 573432024-09-27T07:46:00027 September 2024 07:46:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip on Lowering Condenser Vacuum ENS 570212024-03-11T17:37:00011 March 2024 17:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Manual Reactor Trip ENS 568262023-11-01T10:48:0001 November 2023 10:48:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Manual Reactor Trip Due to Trip of Reactor Feed Pump ENS 564462023-03-31T18:32:00031 March 2023 18:32:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram and Automatic Actuation of Containment Isolation Valves (Civs) ENS 556792021-12-29T20:52:00029 December 2021 20:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip and Automatic Actuation of Containment Isolation Valves ENS 553942021-08-03T14:26:0003 August 2021 14:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 539532019-03-24T05:59:00024 March 2019 05:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Degrading Condenser Vacuum ENS 538932019-02-23T07:12:00023 February 2019 07:12:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of 2C Emergency Diesel Generator ENS 527002017-04-21T03:45:00021 April 2017 03:45:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Reactor Protection System Actuation While Shutdown ENS 525582017-02-16T18:20:00016 February 2017 18:20:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unexpected Autostart of an Emergency Diesel Generator ENS 519502016-05-23T14:09:00023 May 2016 14:09:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Plant Hatch Unit 2 Containment Isolation Valve Actuation ENS 487602013-02-16T08:10:00016 February 2013 08:10:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Protection System Scram Signal Due to Scram Discharge Volume High Level ENS 487382013-02-10T12:00:00010 February 2013 12:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Inserted Due to Degrading Reactor Water Chemistry ENS 473692011-10-24T20:11:00024 October 2011 20:11:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Erratic Irm Indications During Startup ENS 458502010-04-16T23:17:00016 April 2010 23:17:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Cooling Accident Signal Due to High Drywell Pressure Signal ENS 451482009-06-23T07:51:00023 June 2009 07:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to High Reactor Water Level ENS 450712009-05-15T09:19:00015 May 2009 09:19:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Group 1 Isolation of All Main Steam Valves While Performing a Special Procedure ENS 450522009-05-10T14:41:00010 May 2009 14:41:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Intermediate Range Reactor Scram During Transition to Run ENS 450492009-05-08T19:15:0008 May 2009 19:15:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertant Main Steam Isolation While Performing Maintenance ENS 446792008-11-22T15:18:00022 November 2008 15:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Manual Reactor Scram After Feed Pump Trip ENS 443372008-07-04T12:39:0004 July 2008 12:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram on Turbine Trip ENS 440462008-03-07T19:46:0007 March 2008 19:46:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Automatic Reactor Scram with Hpci/Rcic Actuation Due to Loss of Condensate Feedwater ENS 435522007-08-07T19:06:0007 August 2007 19:06:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram on Low Reactor Water Level Following Partial Loss of Condensate Feedwater Flow ENS 420962005-10-29T17:25:00029 October 2005 17:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unusual Event - Main Transformer Fire ENS 417252005-05-23T21:47:00023 May 2005 21:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Due to Condenser Hotwell Chemistry ENS 410702004-09-25T05:06:00025 September 2004 05:06:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Group 2 Containment Isolation Actuation ENS 405652004-03-03T18:45:0003 March 2004 18:45:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Swing Diesel Generator Auto Started from a Bus Undervoltage Valid Signal 2024-09-27T07:46:00 | |
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