ENS 57810
From kanterella
ENS Event | |
|---|---|
18:18 Jul 13, 2025 | |
| Title | Automatic Reactor Trip |
| Event Description | The following information was provided by the licensee via phone and email:
At 1418 EDT on 7/13/2025, with Unit 2 in mode 1 at 100 percent power, the reactor automatically tripped due to a main turbine trip. The trip was not complicated with all systems responding normally post trip. Operators responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the steam dump system and the auxiliary feedwater (AFW) system. Unit 1 is not affected. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72 (b)(2)(iv)(B). The expected actuation of the AFW system (an engineered safety feature) is being reported as an eight-hour report under 10 CFR 50.72 (b)(3)(iv)(A). There was no impact to 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: The cause of the main turbine trip was due to the loss of both main feed pumps due to a loss of secondary power. The cause of the loss of secondary power is still being investigated. |
| Where | |
|---|---|
Watts Bar  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-1.13 h-0.0471 days <br />-0.00673 weeks <br />-0.00155 months <br />) | |
| Opened: | Ryan Nessell 17:10 Jul 13, 2025 |
| NRC Officer: | Josue Ramirez |
| Last Updated: | Jul 13, 2025 |
| 57810 - NRC Website
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Watts Bar with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 578102025-07-13T18:18:00013 July 2025 18:18:00
[Table view]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 575002025-01-17T07:03:00017 January 2025 07:03:00 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 572142024-07-08T19:21:0008 July 2024 19:21:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 570062024-03-05T06:32:0005 March 2024 06:32:00 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 569702024-02-16T03:24:00016 February 2024 03:24:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Emergency Diesel Generator System ENS 569352024-01-28T02:41:00028 January 2024 02:41:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 566602023-08-04T21:46:0004 August 2023 21:46:00 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 565932023-06-27T20:26:00027 June 2023 20:26:00 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 551432021-03-17T15:04:00017 March 2021 15:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip ENS 549972020-11-15T06:44:00015 November 2020 06:44:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of the Emergency Diesel Generators ENS 547202020-05-20T09:21:00020 May 2020 09:21:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of Emergency Diesel Generators ENS 545322020-02-19T14:36:00019 February 2020 14:36:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Loss of Control of Steam ENS 542522019-09-01T00:55:0001 September 2019 00:55:00 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 Steam Generator Level Control ENS 540772019-05-22T06:33:00022 May 2019 06:33:00 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 Failure of Main Feedwater Regulating Valve ENS 536972018-10-27T04:00:00027 October 2018 04:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Following Startup ENS 535572018-08-22T04:00:00022 August 2018 04:00:00 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 534672018-06-22T04:00:00022 June 2018 04:00:00 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 533272018-04-12T13:20:00012 April 2018 13:20:00 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 531322017-12-20T15:40:00020 December 2017 15:40:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation System Actuations Due to Opening of Feeder Breaker to Shutdown Board ENS 531122017-12-11T13:57:00011 December 2017 13:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip in Response to Indication of Multiple Dropped Control Rods ENS 529122017-08-17T16:05:00017 August 2017 16:05:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Actuation of Turbine Driven Auxiliary Feedwater Pump Due to Loss of 6.9Kv Shutdown Board ENS 528722017-07-25T08:28:00025 July 2017 08:28:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Rod Position Indication System Being Inoperable ENS 527322017-05-04T21:09:0004 May 2017 21:09:00 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 Failed Reactor Coolant Pump Power Transfer ENS 527252017-05-02T23:45:0002 May 2017 23:45:00 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 Failed Reactor Coolant Pump Power Transfer ENS 526302017-03-23T04:14:00023 March 2017 04:14:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Auxiliary Feed Water ENS 526252017-03-20T12:13:00020 March 2017 12:13:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip as a Result of Secondary Plant Transient ENS 522102016-08-31T01:20:00031 August 2016 01:20:00 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 Notice of Unusual Event - Fire in a Main Bank Transformer ENS 521942016-08-23T17:56:00023 August 2016 17:56:00 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 a Loss of Main Feedwater ENS 521772016-08-13T07:36:00013 August 2016 07:36:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Turbine Driven Auxiliary Feed Water Pump ENS 520262016-06-20T19:40:00020 June 2016 19:40:00 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 519822016-06-05T16:27:0005 June 2016 16:27:00 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 Reactor Trip and Eccs Actuation Caused by Turbine Governor Valve Failure ENS 519402016-05-17T20:30:00017 May 2016 20:30:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Specified System Actuation - Loss of 1 B-B Electrical Buss ENS 518152016-03-22T15:31:00022 March 2016 15:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Watts Bar Automatic Reactor Trip ENS 508392015-02-21T15:32:00021 February 2015 15:32:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Inserted Due to Rapid Loss of Main Condenser Vacuum ENS 502782014-07-13T23:37:00013 July 2014 23:37:00 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 Automatic Feedwater Heater Isolation ENS 491542013-06-28T17:30:00028 June 2013 17:30:00 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 Offsite Electrical Fault ENS 484142012-10-17T03:30:00017 October 2012 03:30:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation All Four Emergency Diesel Generators Auto-Start on Valid Undervoltage Signal ENS 482382012-08-28T07:32:00028 August 2012 07:32:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Following Failure of a Feedwater Regulating Valve ENS 469022011-05-29T05:55:00029 May 2011 05:55:00 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 464182010-11-14T11:52:00014 November 2010 11:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Loss of Cooling to the 'A' Phase Main Bank Transformer ENS 461772010-08-15T19:24:00015 August 2010 19:24:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Aux Feedwater System Actuation During Power Reduction for Turbine Maintenance ENS 459442010-05-21T23:37:00021 May 2010 23:37:00 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 ENS 452102009-07-17T21:42:00017 July 2009 21:42:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Emergency Diesel Generators Due to Loss of Power to Safety Related Bus ENS 445062008-09-20T13:06:00020 September 2008 13:06:00 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 Turbine Trip ENS 443882008-08-07T06:28:0007 August 2008 06:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Trip from 50% Power Following Low Pressure Heater String Isolation ENS 427442006-07-31T16:13:00031 July 2006 16:13:00 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 Trip ENS 426102006-05-30T21:00:00030 May 2006 21:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip on High Turbine Vibration ENS 410542004-09-19T08:56:00019 September 2004 08:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip in Response to Indication of Dropped Control Rods ENS 404542004-01-16T16:37:00016 January 2004 16:37:00 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 401002003-08-25T13:45:00025 August 2003 13:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Turbine Trip/Reactor Trip Due to a Sudden Pressure Relay Signal from Main Transformer Bank "1C 2025-07-13T18:18:00 | |
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