ENS 56478
ENS Event | |
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05:48 Apr 20, 2023 | |
Title | Automatic Reactor Trip Due to a Turbine Trip |
Event Description | The following information was provided by the licensee via phone and email:
At 0148 Eastern Daylight Time (EDT) on April 20, 2023, with Unit 1 in Mode 1 at 100% power, the reactor automatically tripped due to a turbine trip. Turbine Bypass valves did not open on the trip due to Turbine Protection system power supply failure; the Safety Relief Valves (SRVs) opened automatically to control reactor pressure. Reactor Pressure reached approximately 1095 psig on the trip; exceeding the 1060 psig RPS trip setpoint. Operations responded and stabilized the plant. Operations was able to transition from SRVs to main steam line drains to the condenser. Reactor water level is being maintained via the Condensate / Feedwater system. Decay heat is being removed by discharging steam to the main condenser using the main steam line drains. Due to the Reactor Protection System (RPS) actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Reactor water level reached low level 1 (LL1) following the reactor trip. The LL1 signal causes Group 2 (i.e., floor and equipment drain isolation valves), Group 6 (i.e., monitoring and sampling isolation valves), and Group 8 (i.e., shutdown cooling isolation valves) isolations. The LL1 isolations occurred as designed; the Group 8 valves were closed at the time of the event. Due to the valid Primary Containment Isolation System (PCIS) actuation and RPS actuation from the reactor pressure signal, this event is also being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A). Unit 2 is not affected by this event. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
Where | |
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Brunswick North Carolina (NRC Region 2) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
Time - Person (Reporting Time:+-0.4 h-0.0167 days <br />-0.00238 weeks <br />-5.4792e-4 months <br />) | |
Opened: | Chris Denton 05:24 Apr 20, 2023 |
NRC Officer: | Thomas Herrity |
Last Updated: | Apr 20, 2023 |
56478 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | A/R |
Before | Power Operation (100 %) |
After | Hot Shutdown (0 %) |
Brunswick with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 569772024-02-19T04:25:00019 February 2024 04:25:00
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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 409542004-08-14T16:59:00014 August 2004 16:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Rps Actuation Due to Loss of Offsite Power 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 | |