ENS 56803
ENS Event | |
|---|---|
16:10 Oct 19, 2023 | |
| Title | Automatic Reactor Trip |
| Event Description | The following information was provided by the licensee via email:
On 10/19/2023, at approximately 1110 [CST], with Unit 1 in mode 1 at 100 percent power, the reactor automatically tripped. All control rods fully inserted into the core following the trip. All safety functions operated as designed. The cause of the trip is being investigated. Operations responded and stabilized the plant. Auxiliary feedwater actuated as expected. Decay heat is being removed by the steam generator through the steam generator power operated relief valve. The trip was complex as non-safety related power was lost to both Unit 1 and Unit 2. Unit 1 is currently in mode 3 and on natural recirculation as both reactor coolant pumps are without power. Unit 2 is currently in a refueling outage with all fuel in the spent fuel pool (SFP). SFP cooling was lost for approximately 70 minutes. No impacts to the SFP temperature were observed. 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). Due to the actuation of the auxiliary feedwater system following the reactor trip, this event is being reported as a specified system actuation in accordance with the reporting criteria of 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.
The second paragraph of the original report is amended as follows to correct information regarding the spent fuel pool for Unit 2: Unit 2 is currently in a refueling outage with all fuel in the spent fuel pool (SFP). SFP cooling was maintained at all times with one train of SFP cooling. The second train lost power and was restarted approximately 70 minutes [after power was lost]. No impacts to the SFP temperature were observed. Notified R3DO (Orth) and IR MOC (Crouch) and NRR EO (Felts) via email |
| Where | |
|---|---|
Prairie Island  Minnesota (NRC Region 3) | |
| 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:+-0.92 h-0.0383 days <br />-0.00548 weeks <br />-0.00126 months <br />) | |
| Opened: | Martin Cabiro 15:15 Oct 19, 2023 |
| NRC Officer: | Ernest West |
| Last Updated: | Oct 19, 2023 |
| 56803 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
Prairie Island with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 570032024-03-03T17:42:0003 March 2024 17:42:00
[Table view]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 Loss of Main Feedwater Pump Suction ENS 568032023-10-19T16:10:00019 October 2023 16:10:00 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 565432023-05-27T23:34:00027 May 2023 23:34:00 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 Notification of Unusual Event Due to Multiple Fire Alarms in Containment Not Verified within 15 Minutes ENS 555032021-10-03T20:25:0003 October 2021 20:25:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Specified System Actuation ENS 548592020-08-26T18:19:00026 August 2020 18:19:00 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 Flux Rate ENS 534082018-05-17T16:15:00017 May 2018 16:15:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of Emergency Diesel Generator ENS 516092015-12-17T19:18:00017 December 2015 19:18:00 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 Unusual Event Declared Due to Fire Alarm in Containment Not Verified within 15 Minutes ENS 511362015-06-07T12:35:0007 June 2015 12:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Resulting from Turbine Trip on Low Oil Pressure ENS 511072015-06-01T03:20:0001 June 2015 03:20:00 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 Trip of Condensate and Main Feedwater Pump ENS 509502015-04-03T11:52:0003 April 2015 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 Scram Due to Loss of Main Feedwater Pump ENS 502212014-06-23T16:07:00023 June 2014 16:07:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Auto Start Due to Degraded Bus Voltage Signal ENS 481862012-08-14T08:12:00014 August 2012 08:12:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Based on Both Emergency Diesels Being Declared Inoperable ENS 476832012-02-22T05:42:00022 February 2012 05:42:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Feedwater Heater Hi Hi Alarm ENS 470172011-07-01T20:52:0001 July 2011 20:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Manual Trip Due to Electro-Hydraulic Control Fluid Leak on Turbine Stop Valve ENS 468302011-05-09T12:22:0009 May 2011 12:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Upon Turbine Trip Due to Main Generator Lockout ENS 459522010-05-25T08:14:00025 May 2010 08:14:00 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 458512010-04-17T03:37:00017 April 2010 03:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip Due to Turbine Trip ENS 450772009-05-18T18:05:00018 May 2009 18:05:00 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 Due to Condenser Vacuum ENS 449202009-03-19T20:32:00019 March 2009 20:32:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Start of a Cooling Water Pump During Testing ENS 446152008-10-30T19:17:00030 October 2008 19:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Manually Tripped Due to Failure in Rod Control System ENS 443772008-07-31T13:17:00031 July 2008 13:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip During Testing ENS 432802007-04-05T14:08:0005 April 2007 14:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Automatic Reactor Trip Caused by Spurious Safety Injection During Testing ENS 425042006-04-14T19:25:00014 April 2006 19:25:00 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 Condensate Pump and Feedwater Pump Trip 2024-03-03T17:42:00 | |