ENS 57929
From kanterella
ENS Event | |
|---|---|
01:20 Sep 15, 2025 | |
| Title | Manual Reactor Trip |
| Event Description | The following information was provided by the licensee via phone and email:
At 2020 CDT [on 9/14/2025], [Comanche Peak] Unit 2 reactor was manually tripped due to a malfunction of the electro-hydraulic control (EHC) system on the main turbine. All auxiliary feedwater pumps started due to steam generator `Lo-Lo' levels post trip. This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) for a reactor trip and 10 CFR 50.72(b)(3)(iv)(A) for an actuation of auxiliary feedwater. Unit 2 is being maintained in hot standby (mode 3) in accordance with integrated plant operating procedures. Decay heat is being rejected to the main condenser via the steam dump valves." The NRC Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Unit 1 was not affected. The cause of the malfunction of EHC is unknown and under investigation. All rods fully inserted upon the reactor being tripped. |
| Where | |
|---|---|
Comanche Peak  Texas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-1.07 h-0.0446 days <br />-0.00637 weeks <br />-0.00147 months <br />) | |
| Opened: | Victor Alanis 00:16 Sep 15, 2025 |
| NRC Officer: | Ernest West |
| Last Updated: | Sep 15, 2025 |
| 57929 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | (100 %) |
| After | (0 %) |
WEEKMONTHYEARENS 579502025-09-24T23:29:00024 September 2025 23:29:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip ENS 579292025-09-15T01:20:00015 September 2025 01:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip ENS 570332024-03-17T20:15:00017 March 2024 20:15:00 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 Main Feedwater Pump Trip ENS 570242024-03-12T13:16:00012 March 2024 13:16:00 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 565802023-06-16T23:32:00016 June 2023 23:32:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to LO-LO Steam Generator Level ENS 560912022-09-06T04:45:0006 September 2022 04:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip ENS 552952021-06-07T20:27:0007 June 2021 20:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip on Turbine Trip Due to Fault and Fire in the Main Transformer ENS 544602020-01-01T18:53:0001 January 2020 18:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip and Specified System Actuation ENS 539062019-03-02T09:17:0002 March 2019 09:17:00 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 Isolation Valve Closure ENS 535502018-08-13T05:00:00013 August 2018 05:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Generator Lockout ENS 530912017-11-26T02:25:00026 November 2017 02:25:00 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 Loss of Main Feed Water ENS 529452017-09-02T02:40:0002 September 2017 02:40:00 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 Two Dropped Rods ENS 514442015-10-03T15:00:0003 October 2015 15:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip During Shutdown for a Refueling Outage ENS 497432014-01-18T14:40:00018 January 2014 14:40:00 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 494972013-11-02T02:47:0002 November 2013 02:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip During Solid State Protection System Testing ENS 485142012-11-17T16:23:00017 November 2012 16:23:00 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 Steam Generator Water Level ENS 484752012-11-02T06:42:0002 November 2012 06:42:00 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 High Reactor Coolant Pump Motor Bearing Temperature ENS 468632011-05-19T19:07:00019 May 2011 19:07:00 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 a Main Condenser Tube Leak ENS 456172010-01-09T16:28:0009 January 2010 16:28:00 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 Sudden Pressure in Output Transformer ENS 440672008-03-16T16:37:00016 March 2008 16:37:00 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 Broken Sensing Line ENS 429452006-10-29T21:20:00029 October 2006 21:20:00 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 Lowering Steam Generator Level ENS 429372006-10-27T08:08:00027 October 2006 08:08:00 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 Loss of Both Main Feed Pumps ENS 404062003-12-22T14:27:00022 December 2003 14:27:00 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 Main Turbine Trip 2025-09-24T23:29:00 | |
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