ENS 56935
ENS Event | |
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02:41 Jan 28, 2024 | |
Title | Automatic Reactor Trip |
Event Description | The following information was provided by the licensee via email:
At 2141 EDT, with Unit 2 in Mode 1 at 100 percent power, the reactor automatically tripped due to a main turbine trip. The trip was not complex, with all systems responding normally post-trip. Operations responded and stabilized the plant. Decay heat is being removed using the auxiliary feedwater and steam dump systems. 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 auxiliary feedwater 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 on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. All control rods are fully inserted. The cause of the turbine trip is being investigated. The licensee notified the NRC Resident Inspector. |
Where | |
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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:+-3.03 h-0.126 days <br />-0.018 weeks <br />-0.00415 months <br />) | |
Opened: | Ryan Nessell 23:39 Jan 27, 2024 |
NRC Officer: | Bill Gott |
Last Updated: | Jan 27, 2024 |
56935 - NRC Website
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Unit 2 | |
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Reactor critical | Critical |
Scram | A/R |
Before | Power Operation (100 %) |
After | Hot Standby (0 %) |
Watts Bar ![]() | |
WEEKMONTHYEARENS 572142024-07-08T19:21:0008 July 2024 19:21:00
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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 2024-07-08T19:21:00 | |