ENS 55627
ENS Event | |
|---|---|
16:25 Dec 6, 2021 | |
| Title | Valid Safety System Actuation |
| Event Description | On December 6, 2021, at 1125 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.280625e-4 months <br /> Eastern Standard Time (EST), during planned maintenance activities, electrical power was lost to the 4160V emergency bus E-3. The power loss to emergency bus E-3 affected both Unit 1 and 2. Emergency Diesel Generator #3 received an automatic start signal but was under clearance for planned maintenance. Emergency bus E-3 was re-energized at 1315 EST hours via offsite power.
The loss of power to E3 resulted in Unit 2 Primary Containment Isolation System (PCIS) Group 2 (i.e., Drywell Equipment and Floor Drain, Residual Heat Removal (RHR) Discharge to Radwaste, and RHR Process Sample), Group 3 (i.e., Reactor Water Cleanup), Group 6 (i.e., Containment Atmosphere Control/Dilution, Containment Atmosphere Monitoring, and Post Accident Sampling Systems), and Group 10 (i.e., air isolation to the drywell) isolations. The actuations of PCIVs were completed and the affected equipment responded as designed. Per design, no Unit 1 safety system group isolations or actuations occurred. Other Unit 2 actuations included the Reactor Building Ventilation System isolation (i.e., Secondary Containment isolation), and the automatic start signal to the Standby Gas Treatment (SGT) System trains A and B and the Control Room Emergency Ventilation System (CREV). Systems functioned as designed. Safety systems functioned as designed following the de-energization of bus E-3. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of PCIS on Unit 2 and an automatic start signal to Emergency Diesel Generator #3. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. Except for the Emergency Diesel Generator, which is out of service for planned maintenance, all equipment has been returned to its normal alignment.
The loss of power to E3 resulted in Unit 1 Primary Containment Isolation System (PCIS) Group 6 (i.e., Containment Atmosphere Control/Dilution, Containment Atmosphere Monitoring, and Post Accident Sampling Systems). Other Unit 1 actuations included the Reactor Building Ventilation System isolation (i.e., Secondary Containment isolation), and the automatic start signal to the Standby Gas Treatment (SGT) System trains A and B and the Control Room Emergency Ventilation System (CREV). Systems functioned as designed. Safety systems functioned as designed following the de-energization of bus E-3. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of PCIS on Unit 1. All Unit 1 equipment was returned to its normal alignment. The NRC Resident will be notified. Notified R2DO (Miller). |
| Where | |
|---|---|
Brunswick  North Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+1.82 h0.0758 days <br />0.0108 weeks <br />0.00249 months <br />) | |
| Opened: | Joel Gordon 18:14 Dec 6, 2021 |
| NRC Officer: | Thomas Kendzia |
| Last Updated: | Dec 6, 2021 |
| 55627 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 569772024-02-19T04:25:00019 February 2024 04:25:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Emergency Diesel Generator ENS 564782023-04-20T05:48:00020 April 2023 05:48:00 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 Turbine Trip ENS 556272021-12-06T16:25:0006 December 2021 16:25:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Safety System Actuation ENS 540162019-04-22T03:07:00022 April 2019 03:07:00 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 Automatic Reactor Trip and Specified System Actuation ENS 539662019-03-30T21:47:00030 March 2019 21:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram and Specified System Actuation ENS 539622019-03-28T20:54:00028 March 2019 20:54:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of the Primary Containment Isolation System and the Reactor Protecton System ENS 539552019-03-25T08:02:00025 March 2019 08:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Four Emergency Diesel Generators ENS 539112019-03-05T10:35:0005 March 2019 10:35:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of the Primary Containment Isolation System ENS 533192018-04-07T12:36:0007 April 2018 12:36:00 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 Pcis Actuation During Stator Cooling System Testing ENS 529742017-09-17T13:38:00017 September 2017 13:38:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator and Primary Containment Isolation System Actuations ENS 526832017-04-17T04:04:00017 April 2017 04:04:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of Emergency Diesel Generators ENS 517152016-02-07T18:26:0007 February 2016 18:26:00 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 Manual Scram and Alert Declaration Due to Electrical Fault Resulting in Fire/Explosion ENS 478172012-04-09T09:29:0009 April 2012 09:29:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Emergency Diesel Generator Actuation ENS 476972012-02-24T05:37:00024 February 2012 05:37:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Reactor Protection System Actuation During Neutron Instrument Testing ENS 476902012-02-23T04:19:00023 February 2012 04:19:00 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 High Delta-P Across Circulating Water Pump Traveling Screens ENS 459022010-05-05T15:44:0005 May 2010 15:44:00 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 Reactor Feed Pump Trip ENS 457322010-02-27T06:58:00027 February 2010 06:58:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Core Isolation Cooling (Rcic) System Manually Started to Maintain Reactor Pressure Vessel Level Following a Pre-Planned Reactor Scram ENS 453752009-09-21T18:46:00021 September 2009 18:46:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Protection System and Primary Containment Isolation System Actuation After Placing Hpci System Inservice ENS 451902009-07-08T14:13:0008 July 2009 14:13:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Emergency Diesel Generator Actuation ENS 446852008-11-26T17:00:00026 November 2008 17:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to Ehc Malfunction ENS 446472008-11-09T16:08:0009 November 2008 16:08:00 Other Unspec Reqmnt, 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 Spurious Srv Opening ENS 444532008-08-30T19:03:00030 August 2008 19:03:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Turbine Electro-Hydraulic Control Malfunction Leads to Reactor Scram ENS 430622006-12-25T10:39:00025 December 2006 10:39:00 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)(2)(iv)(A), System Actuation - ECCS Discharge Reactor Scram Due to Trip from Neutron Monitoring System ENS 429862006-11-11T17:43:00011 November 2006 17:43:00 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 Conductivity Excursion ENS 429552006-11-01T23:37:0001 November 2006 23:37:00 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, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Unit 2 Declared an Unusual Event Due to Loss of Offsite Power to the 4Kv Emergency Buses ENS 418372005-07-13T13:17:00013 July 2005 13:17:00 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 ENS 415822005-04-09T05:50:0009 April 2005 05:50:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scrammed from 61% Power Due to Low Reactor Water Level ENS 402972003-11-04T22:32:0004 November 2003 22:32:00 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 Brunswick Unit 2 Scram Due to Generator/Turbine Trip 2024-02-19T04:25:00 | |