ENS 52918
ENS Event | |
|---|---|
23:05 Aug 20, 2017 | |
| Title | Manual Reactor Scram Due to a Rise in Main Condenser Back Pressure |
| Event Description | On August 20, 2017 at 1605 PDT, Columbia Generating Station was manually scrammed from 100 percent power due to a rise of Main Condenser back pressure. Manual scram of the unit is procedurally required upon a loss of Main Condenser back pressure. Preliminary investigations indicate that the Main Condenser air removal suction valve (AR-V-1) closed, resulting in the Condenser back pressure rising to within 1.0 inch Hg of the setpoint with reactor power greater than 25 percent. Further investigations continue. All control rods fully inserted.
In addition to the closure of the air removal suction valve, one of two Reactor Feedwater startup flow control valves did not adequately operate to control Reactor vessel level and resulted in a high-level (Level-8) actuation tripping the Reactor Feedwater System. All other systems operated as expected. Reactor water level is currently being controlled manually with the start-up level control isolation valve. AR-V-1 has been manually opened with a jumper and temporary air supply. Reactor decay heat is being removed via bypass valves to the Main Condenser. This event is being reported under the following: 10 CFR 50.72(b)(2)(iv)(B), which requires a four-hour notification for any event or condition that results in actuation of the Reactor Protection System when the reactor is critical. The licensee notified the NRC Resident Inspector. The licensee plans to issue a press release.
The licensee is updating the notification to include an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification under 10 CFR 50.72(b)(3)(iv)(A) for a specified system actuation due to a Level 3 isolation signal which occurred approximately 20 minutes after the scram. The licensee is currently in cold shutdown to repair the Reactor Feedwater startup flow control valve. The licensee has notified the NRC Resident Inspector. Notified R4DO (Farnholtz). |
| Where | |
|---|---|
Columbia Generating Station  Washington (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:+-0.32 h-0.0133 days <br />-0.0019 weeks <br />-4.38336e-4 months <br />) | |
| Opened: | Rick Kerrone 22:46 Aug 20, 2017 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Aug 24, 2017 |
| 52918 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Shutdown (0 %) |
Columbia with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 559382022-06-13T16:23:00013 June 2022 16:23:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Partial Loss of Power to RPS During Maintenance ENS 534102018-05-18T13:51:00018 May 2018 13:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Caused by Main Transformer Trip ENS 529182017-08-20T23:05:00020 August 2017 23:05:00 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 a Rise in Main Condenser Back Pressure ENS 524422016-12-18T19:24:00018 December 2016 19:24:00 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 Scram Due to Load Reject from Substation ENS 518262016-03-28T20:22:00028 March 2016 20:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Scram Following Loss of Reactor Closed Cooling ENS 510862015-05-22T07:14:00022 May 2015 07:14:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Emergency Diesel Generator Start Due to Actuation of Undervoltage Circuitry ENS 491202013-06-15T19:22:00015 June 2013 19:22:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Division 1 and 2 Emergency Diesel Generators Power Buses After Momentary Offsite Power Loss ENS 454842009-11-07T15:25:0007 November 2009 15:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to a Main Turbine Digital Electro-Hydraulic Control System Leak ENS 452452009-08-05T14:50:0005 August 2009 14:50:00 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 Toxic Gas from a Switchgear Fire in the Turbine Building ENS 451692009-06-27T03:05:00027 June 2009 03:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Unusual Event Declared Based on Fire Lasting Greater than 15 Minutes ENS 450512009-05-08T17:45:0008 May 2009 17:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram After Loss of Generator Seal Oil ENS 448392009-02-08T19:25:0008 February 2009 19:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Governor Valve Fast Closure Signal ENS 444322008-08-21T23:06:00021 August 2008 23:06:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to a Main Turbine Trip ENS 434572007-06-29T00:17:00029 June 2007 00:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip Due to Condensate Pump Trip ENS 429502006-10-31T12:45:00031 October 2006 12:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Reactor Trip from Turbine Trip on Low Auto Stop Oil Pressure ENS 417902005-06-23T20:46:00023 June 2005 20:46:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit Experienced an Automatic Reactor Scram Due to a Loss of Feedwater Flow ENS 417792005-06-15T21:00:00015 June 2005 21:00:00 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 Turbine Throttle Valve Closure ENS 409642004-08-17T12:28:00017 August 2004 12:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Trip of Reactor Feedwater Pump "a" on Low Suction Pressure. ENS 409592004-08-15T20:03:00015 August 2004 20:03:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Scram Due to Reactor Feedwater Pump Trip ENS 409102004-07-30T17:00:00030 July 2004 17:00:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration Alert Declared at Columbia Generating Station 2022-06-13T16:23:00 | |