ENS 57495
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ENS Event | |
|---|---|
14:50 Jan 16, 2025 | |
| Title | Manual Trip While Shutdown |
| Event Description | The following information was provided by the licensee via phone and email:
At 0950 EST, with Unit 2 in mode 3 at 0 percent power, the reactor was manually tripped due to group 2 of control rod bank D failing to withdraw during rod drop testing. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Decay heat is being removed by the auxiliary feedwater and steam dump systems. Unit 1 is not affected. At the time of the event, Unit 2 was not critical. Therefore, this event is being reported as an eight-hour, non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the reactor protection system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Four controls rods failed to move on demand. All control rods inserted on the trip. |
| Where | |
|---|---|
Sequoyah  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-1.18 h-0.0492 days <br />-0.00702 weeks <br />-0.00162 months <br />) | |
| Opened: | John Ralson 13:39 Jan 16, 2025 |
| NRC Officer: | Robert A. Thompson |
| Last Updated: | Jan 16, 2025 |
| 57495 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | Yes, Manual Scram |
| Before | Hot Standby (0 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 577792025-06-24T07:51:00024 June 2025 07:51:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 2 Manual Reactor Trip ENS 577782025-06-24T04:14:00024 June 2025 04:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Manual Reactor Trip ENS 574952025-01-16T14:50:00016 January 2025 14:50:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Trip While Shutdown ENS 573512024-09-29T09:56:00029 September 2024 09:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip ENS 572852024-08-23T16:19:00023 August 2024 16:19:00 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 572532024-07-30T20:41:00030 July 2024 20:41:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip ENS 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50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Eccs Discharge to Rcs Via Charging System ENS 515592015-11-23T13:44:00023 November 2015 13:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip After Partial Msiv Closure ENS 513922015-09-14T08:26:00014 September 2015 08:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Loss of Power to Vital Instrument Board ENS 512652015-07-27T14:43:00027 July 2015 14:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor/Turbine Trip ENS 512592015-07-24T17:51:00024 July 2015 17:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip on Main Generator Lockout ENS 508782015-03-11T10:21:00011 March 2015 10:21:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to a Nuclear Instrumentation Signal ENS 508562015-03-02T11:45:0002 March 2015 11:45:00 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 487782013-02-24T17:05:00024 February 2013 17:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Loss of Condenser Vacuum Indication ENS 481982012-08-16T23:26:00016 August 2012 23:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip from a Reactor Coolant Pump Trip ENS 471692011-08-19T02:50:00019 August 2011 02:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Reactor Coolant Pump Bus Undervoltage ENS 470812011-07-21T01:29:00021 July 2011 01:29:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Negative Rate Trip Following Rapid Turbine Load Reduction ENS 469912011-06-26T20:14:00026 June 2011 20:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip ENS 464922010-12-20T05:50:00020 December 2010 05:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to a Fire in the Main Generator Bus Duct ENS 464242010-11-17T03:10:00017 November 2010 03:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Based on Decreasing Steam Generator Level ENS 455202009-11-26T07:42:00026 November 2009 07:42:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Trip Due to Loss of Vacuum on Turbine Driven Feedwater Pump ENS 450972009-05-27T23:04:00027 May 2009 23:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip from Power Range High Neutron Flux Rate ENS 450452009-05-07T02:56:0007 May 2009 02:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Feed Regulating Valve Failure ENS 450292009-04-29T01:59:00029 April 2009 01:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Initiated as a Result of a Loss of Condensate Flow ENS 449342009-03-26T08:52:00026 March 2009 08:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip and Aux Feed Water Start Due to Loss of an Off Site Power Source ENS 449352009-03-26T08:52:00026 March 2009 08:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip and Aux Feed Water Start Due to Loss of an Off Site Power Source ENS 446492008-11-09T23:21:0009 November 2008 23:21:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Breakers Opened Manually Due to Indicated Dropped Control Rod ENS 439092008-01-17T00:25:00017 January 2008 00:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Lowering Steam Generator Level ENS 432332007-03-13T19:27:00013 March 2007 19:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to "a" Main Feedwater Pump ENS 431152007-01-23T17:44:00023 January 2007 17:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Feedwater Regulating Valve Failure ENS 424442006-03-22T21:24:00022 March 2006 21:24:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Turbine Trip / Reactor Trip Caused by Main Generator Trip ENS 415832005-04-09T15:11:0009 April 2005 15:11:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on Turbine Trip Due to Low Auto Stop Oil Pressure on Pressure Switches ENS 414372005-02-24T02:06:00024 February 2005 02:06:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip on Low-Low Steam Generator Level ENS 405892004-03-15T20:18:00015 March 2004 20:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Main Generator Electrical Fault Signal ENS 404752004-01-25T08:16:00025 January 2004 08:16:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Auto Start of Turbine Driven Auxiliary Feedwater Pump ENS 403052003-11-10T04:15:00010 November 2003 04:15:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Sequoyah Unit 2 Auxiliary Feedwater Actuation During Outage ENS 401132003-08-28T20:04:00028 August 2003 20:04:00 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 Alert Declared Due to Reactor Protection System Failure 2025-06-24T07:51:00 | |
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