ENS 57418
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ENS Event | |
|---|---|
09:37 Nov 10, 2024 | |
| Title | Manual Reactor Scram |
| Event Description | The following information was provided by the licensee via phone and email:
On November 10, 2024, at 0337 CST, Grand Gulf Nuclear Station (GGNS) was operating in mode 1 at 100 percent power when a manual scram was initiated due to degrading main condenser vacuum. The cause of the degrading main condenser vacuum is not known at this time and is being investigated. All control rods fully inserted and there were no complications. Reactor pressure was initially maintained with main turbine bypass valves. Reactor water level was initially maintained with main feedwater and condensate. At 0457, operators transitioned pressure control to safety relief valves and began using reactor core isolation cooling (RCIC) to maintain reactor water level. This was performed using plant procedures due to degrading vacuum. GGNS is currently in mode 3. Reactor level is being maintained with RCIC and pressure is being maintained using the safety relief valves. The manual reactor protection system (RPS) actuation is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) and the RCIC actuation is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A). The NRC Senior Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At the time of the notification, main steam isolation valves had shut on low vacuum.
The following update was provided by the licensee via phone and email: This update is being made to report the following occurrences which took place after the scram reported in event number 57418. On November 10, 2024, at 0545 CST, a group 1 containment isolation signal resulted in the closure of all MSIVs. The signal was due to continued degradation of condenser vacuum post-trip. At 0620, an automatic RPS actuation occurred when reactor water level lowered to level 3. This RPS actuation occurred with all control rods fully inserted. Reactor water level lowered following closure of an open safety relief valve and was recovered to within the established band. The events are being reported as specified system actuations in accordance with 10 CFR 50.72(b)(3)(iv)(A). The NRC Senior Resident Inspector has been informed of the update. Notified R4DO (Dixon) |
| Where | |
|---|---|
Grand Gulf  Mississippi (NRC Region 4) | |
| 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:+-1.63 h-0.0679 days <br />-0.0097 weeks <br />-0.00223 months <br />) | |
| Opened: | Melissa Limbeck 07:59 Nov 10, 2024 |
| NRC Officer: | Ernest West |
| Last Updated: | Nov 10, 2024 |
| 57418 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Shutdown (0 %) |
Grand Gulf with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 574182024-11-10T09:37:00010 November 2024 09:37:00
[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 Scram ENS 570532024-03-26T16:15:00026 March 2024 16:15:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Actuation of Reactor Protection System ENS 568942023-12-16T09:50:00016 December 2023 09:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Scram Due to Turbine Trip ENS 562822022-12-20T03:01:00020 December 2022 03:01:00 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 Loss of Feedwater Pump ENS 559732022-06-30T19:45:00030 June 2022 19:45:00 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 Loss of Transformer ENS 550302020-12-11T18:04:00011 December 2020 18:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Main Turbine / Generator Trip ENS 549862020-11-06T08:39:0006 November 2020 08:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Turbine/Generator Trip ENS 548552020-08-25T04:05:00025 August 2020 04:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram After Loss of Feedwater - Grand Gulf ENS 548242020-08-08T06:27:0008 August 2020 06:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scram Due to a Turbine High Pressure Control Valve Malfunction ENS 547252020-05-25T09:33:00025 May 2020 09:33:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Main Turbine Trip ENS 540622019-05-12T15:39:00012 May 2019 15:39:00 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)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Reactor Scram Due to Partial Loss of Service Water ENS 538942019-02-23T20:58:00023 February 2019 20:58:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram After Turbine Control Valve Fast Closure ENS 537882018-12-12T06:00:00012 December 2018 06:00:00 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 En Revision Imported Date 12/17/2018 ENS 536082018-09-14T05:00:00014 September 2018 05:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram ENS 533992018-05-12T04:27:00012 May 2018 04:27:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Inadvertent Actuation of the Emergency Diesel Generator ENS 533742018-05-01T20:51:0001 May 2018 20:51:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Plant Received Division One Reactor Pressure Vessel Level 1 Signal ENS 531882018-01-31T00:22:00031 January 2018 00:22:00 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 Main Turbine Load Oscillations ENS 531152017-12-12T15:18:00012 December 2017 15:18:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Edg Due to Loss of Esf Transformer ENS 530902017-11-25T08:38:00025 November 2017 08:38:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram During Startup ENS 526632017-04-04T05:10:0004 April 2017 05:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Condensate Leak ENS 520572016-06-30T22:15:00030 June 2016 22:15:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Multiple Valid Specified System Actuations Due to Loss of Service Transformer 21 ENS 520442016-06-25T19:07:00025 June 2016 19:07:00 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 Turbine Trip ENS 520122016-06-17T07:57:00017 June 2016 07:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram During Testing ENS 518272016-03-29T16:23:00029 March 2016 16:23:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Turbine Trip ENS 518002016-03-17T20:15:00017 March 2016 20:15:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Engineered Safety Feature System Actuation Due to Lightning Strike ENS 507952015-02-08T00:56:0008 February 2015 00:56:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram ENS 499722014-03-29T15:08:00029 March 2014 15:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine Trip ENS 499202014-03-17T10:14:00017 March 2014 10:14:00 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 Steam Leak in Low Pressure Turbine Line ENS 492252013-07-30T19:32:00030 July 2013 19:32:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Turbine Generator Trip ENS 486732013-01-15T00:05:00015 January 2013 00:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram from 100% Power Due to a Turbine/Generator Trip ENS 486522013-01-05T05:37:0005 January 2013 05:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine/Generator Trip ENS 486372012-12-29T06:18:00029 December 2012 06:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Turbine/Generator Trip ENS 477982012-04-02T20:11:0002 April 2012 20:11:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Autostart of Division 3 Diesel Generator Following 4160 Volt Line Outage ENS 476792012-02-20T01:04:00020 February 2012 01:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram During Shutdown Due to Lowering Reactor Vessel Water Level (Rvwl) ENS 457532010-03-08T22:35:0008 March 2010 22:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram on Low Reactor Water Level ENS 450442009-05-06T04:27:0006 May 2009 04:27:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Auto-Start and Loading of Emergency Diesel Generator to Safety Bus Due to Undervoltage Condition ENS 446012008-10-26T16:25:00026 October 2008 16:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram and Isolation Due to Turbine Trip ENS 445952008-10-23T12:20:00023 October 2008 12:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram with Manual Rcic Initiation ENS 440862008-03-21T20:25:00021 March 2008 20:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram from a Main Turbine Trip ENS 438992008-01-12T22:26:00012 January 2008 22:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Degraded Cooling to Main Transformers ENS 435842007-08-21T19:15:00021 August 2007 19:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Scrammed Due to Reactor Water Level 3 Rps Actuation ENS 433762007-05-19T16:27:00019 May 2007 16:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Due to Turbine Trip on Loss of Condenser Vacuum ENS 414052005-02-12T01:59:00012 February 2005 01:59:00 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 Rps Actuation 2024-03-26T16:15:00 | |
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