ENS 55750
ENS Event | |
|---|---|
03:07 Feb 22, 2022 | |
| Title | Manual Reactor Trip |
| Event Description | The following information was provided by the licensee via fax or email:
At 2207 [EST] on 2/21/2022 with Unit 2 in Mode 1 at 68 percent power, the reactor was manually tripped due to lowering water level in the 2A Steam Generator. The trip was not complex with all systems responding normally post-trip. Operators responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Units 1 and 3 were not affected. 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). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
The following information was provided by the licensee via phone and email: On 2/21/2022, Unit 2 was in Mode 1 increasing reactor power following startup from a forced outage. At 2205 [EST] with Unit 2 at 68 percent power, a feedwater control valve failed to properly control feedwater flow to the 2A Steam Generator and the Integrated Control System initiated an automatic runback. At 2207 [EST], the reactor was manually tripped from 39 percent power due to lowering water level in the 2A Steam Generator. Immediately following the manual reactor trip, an actuation of the Emergency Feedwater System (EFW) occurred. The 2A and 2B Motor Driven Emergency Feedwater (MDEFW) pumps automatically started as designed when the 'low steam generator level' signal was received for the 2A Steam Generator. The trip was not complex with all systems responding normally post-trip. Operators responded and stabilized the plant. Decay heat was removed by discharging steam to the main condenser using the turbine bypass valves. Units 1 and 3 were not affected. Unit 2 was restarted on 2/27/2022 following repairs. Due to the Reactor Protection System actuation while critical, this event was reported on 2/22/2022 as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Following further evaluation, it was determined that a valid EFW actuation occurred, therefore this event is now also being reported as a late 8-hour non-emergency notification of a valid actuation of the EFW system in accordance with 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. Notified the R2DO (Miller). |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| 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:+-1.38 h-0.0575 days <br />-0.00821 weeks <br />-0.00189 months <br />) | |
| Opened: | Carl Seymour 01:44 Feb 22, 2022 |
| NRC Officer: | Brian P. Smith |
| Last Updated: | Mar 23, 2022 |
| 55750 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (68 %) |
| After | Hot Standby (0 %) |
Oconee with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 558882022-05-07T03:10:0007 May 2022 03:10:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of Emergency Feedwater ENS 557502022-02-22T03:07:00022 February 2022 03:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip ENS 558002022-02-13T21:25:00013 February 2022 21:25:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Feedwater System Actuation ENS 557332022-02-05T08:57:0005 February 2022 08:57:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event Declared Due to Visual Observation of Smoke and Multiple Fire Alarms in the West Penetration Room ENS 556382021-12-10T05:49:00010 December 2021 05:49:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip ENS 556122021-11-27T10:19:00027 November 2021 10:19:00 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 Automatic Actuation of the Emergency AC Electrical Power System ENS 546612020-04-11T01:25:00011 April 2020 01:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip ENS 536772018-10-19T04:00:00019 October 2018 04:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Turbine Steam Seal Header Pressure Malfunction ENS 533292018-04-13T06:27:00013 April 2018 06:27:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Following Main Feedwater Control Problem ENS 528702017-07-24T20:38:00024 July 2017 20:38:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Load Rejection ENS 517702016-03-06T20:20:0006 March 2016 20:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Emergency Declaration Due to Fire/Explosion in the Main Transformer ENS 512682015-07-27T13:56:00027 July 2015 13:56:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Valid Actuation of Unit 2 Emergency Feedwater System During Startup ENS 507812015-01-31T19:31:00031 January 2015 19:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Rps Actuation Due to Oscillations in the Feedwater System ENS 494712013-10-24T09:53:00024 October 2013 09:53:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip from Full Power Due to Feedwater System Oscillations ENS 461592010-08-07T18:51:0007 August 2010 18:51:00 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 Reactor Coolant Pumps High Vibration ENS 450882009-05-22T00:15:00022 May 2009 00:15:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Rps Actuation (Reactor Trip) Due to Generator Phase Differential Lockout ENS 446382008-11-07T13:34:0007 November 2008 13:34:00 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 441092008-03-31T17:52:00031 March 2008 17:52:00 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 Turbine Trip During Maintenance Activities ENS 431692007-02-15T21:54:00015 February 2007 21:54:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 and Unit 2 Reactor Trip ENS 425762006-05-15T14:59:00015 May 2006 14:59:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Momentary Loss of Dhr Due to Automatic Actuation of the Keowee Emergency Power Supply ENS 424932006-04-12T17:35:00012 April 2006 17:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit 2 Experienced an Automatic Reactor Trip Following the Loss of the "2B2" Reactor Coolant Pump ENS 419662005-08-31T18:28:00031 August 2005 18:28:00 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)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Unit 3 Experienced an Automatic Reactor Trip During Routine Testing ENS 405482004-02-26T16:51:00026 February 2004 16:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Rps Actuation While Critical 2022-05-07T03:10:00 | |