ENS 54795
From kanterella
ENS Event | |
|---|---|
09:35 Jul 21, 2020 | |
| Title | Biofouling of Intake Structure Leads to Manual Reactor Scram of Unit 1 |
| Event Description | The following was received from TVA - Brown's Ferry at 0858, 21 July 20.
On July 21, 2020, at 0435 hours0.00503 days <br />0.121 hours <br />7.19246e-4 weeks <br />1.655175e-4 months <br /> Central Daylight Time, Browns Ferry Unit 1 inserted a manual reactor scram due to degrading main condenser vacuum from marine biofouling at the intake structure. Browns Ferry Unit 2 is in Mode 4 and Browns Ferry Unit 3 is at approximately 76% rated thermal power and stable. Primary Containment Isolation Systems received an actuation signal for groups 2, 3, 6, 8 on reactor water level below +2". All Primary Containment Isolation System groups that received an actuation signal performed as designed. Additionally, all other systems functioned as designed. This event is reportable within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per 10CFR50.72(b)(2)(iv)(B) - Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. This event also requires an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> report per 10CFR50.72(b )(3)(iv)(A), Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B), (1) Reactor protection system (RPS) including: reactor scram or reactor trip, except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation and (2) General containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs). The NRC Resident Inspector has been notified." The plant is stable in Mode 3 and will remain shutdown until marine growth clogging the intake structure abates. |
| Where | |
|---|---|
Browns Ferry  Alabama (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:+-0.62 h-0.0258 days <br />-0.00369 weeks <br />-8.49276e-4 months <br />) | |
| Opened: | Todd Christensen 08:58 Jul 21, 2020 |
| NRC Officer: | Thomas Herrity |
| Last Updated: | Jul 21, 2020 |
| 54795 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (40 %) |
| After | Hot Shutdown (0 %) |
WEEKMONTHYEARENS 565312023-05-20T08:15:00020 May 2023 08:15:00
[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 Scram ENS 547952020-07-21T09:35:00021 July 2020 09:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Biofouling of Intake Structure Leads to Manual Reactor Scram of Unit 1 ENS 547942020-07-20T18:25:00020 July 2020 18:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Biofouling of Intake Structure Leads to Manual Reactor Scram of Unit 2 and Downpower of Units 1 & 3 ENS 543022019-10-01T08:07:0001 October 2019 08:07:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram During Reactor Startup ENS 539232019-03-10T04:59:00010 March 2019 04:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Scram Resulting in Rps and Eccs Actuation ENS 532692018-03-18T16:58:00018 March 2018 16:58:00 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 Control Valve Closure ENS 531622018-01-10T15:28:00010 January 2018 15:28:00 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 Control Valve Fast Closure Scram Signal ENS 526482017-03-29T23:44:00029 March 2017 23:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Initiated During Startup ENS 504042014-08-26T22:30:00026 August 2014 22:30:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Turbine Generator Neutral Overvoltage Causes a Reactor Scram ENS 500902014-05-06T13:30:0006 May 2014 13:30:00 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 Low Reactor Water Level During Instrument Testing ENS 499282014-03-19T03:52:00019 March 2014 03:52:00 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 Failure to Control Main Turbine Moisture Separator Level ENS 488292013-03-19T09:02:00019 March 2013 09:02:00 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 Lowering Condenser Vacuum ENS 487822013-02-25T19:13:00025 February 2013 19:13:00 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 Automatic Scram Due to a Turbine Trip from a Loss of Condenser Vacuum ENS 486232012-12-22T17:52:00022 December 2012 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 Scram Due to Loss of Power to the Reactor Protection System ENS 479722012-05-29T08:31:00029 May 2012 08:31:00 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 Main Generator Load Reject Signal ENS 479552012-05-24T11:39:00024 May 2012 11:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram During Startup ENS 479422012-05-22T07:49:00022 May 2012 07:49:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Scram Due to Reactor Protection System Being De-Energized ENS 472992011-09-28T09:14:00028 September 2011 09:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to a Turbine Trip ENS 467932011-04-27T22:01:00027 April 2011 22:01:00 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)(xiii), Loss of Emergency Preparedness Notification of Unusual Event Due to Loss of Offsite Power ENS 465112010-12-26T22:20:00026 December 2010 22:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to High Vibration on Main Generator Exciter ENS 459902010-06-09T08:31:0009 June 2010 08:31:00 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 Closure of Main Steam Isolation Valves ENS 453912009-09-30T04:23:00030 September 2009 04:23:00 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 Unit 2 Manually Scrammed After Trip of an Operating Condensate Pump and Rapidly Lowering Rvwl ENS 452902009-08-24T23:50:00024 August 2009 23:50:00 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 Condensate Booster Pump Trip Resulting in a Manual Reactor Scram ENS 448602009-02-18T09:51:00018 February 2009 09:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Turbine Trip Due to Power Load Unbalance Signal on Main Generator Resulting in Reactor Scram ENS 448542009-02-16T11:13:00016 February 2009 11:13:00 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 Stator Cooling Water ENS 445402008-10-05T03:08:0005 October 2008 03:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram Following Reverse Power Signal on Main Generator ENS 438782008-01-01T03:40:0001 January 2008 03:40:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 3 Automatic Scram Due to Main Generator Load Reject Signal ENS 437182007-10-12T13:02:00012 October 2007 13:02:00 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 Trip ENS 436132007-09-03T07:14:0003 September 2007 07:14:00 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 Electro-Hydraulic Control (Ehc) System Leak ENS 435602007-08-11T22:51:00011 August 2007 22:51:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Scram Due to Neutron Monitoring Trip Signal ENS 434142007-06-09T16:00:0009 June 2007 16:00:00 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 Turbine Trip as a Result of High Moisture Separator Reheater Tank Level ENS 433812007-05-24T07:11:00024 May 2007 07:11:00 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 Electro-Hydraulic Control (Ehc) System Leak ENS 431592007-02-09T18:08:0009 February 2007 18:08:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Reactor Scram Due to Low Reactor Water Level ENS 430922007-01-11T14:16:00011 January 2007 14:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Scram When Turbine Output Breakers Opened ENS 428132006-08-30T03:25:00030 August 2006 03:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram Due to Electro-Hydraulic Oil Leak ENS 427872006-08-19T16:05:00019 August 2006 16:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Scram of Unit 3 Due to the Loss of Both Reactor Recirculation Pumps ENS 421022005-10-31T19:18:00031 October 2005 19:18:00 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 Trip of Main Turbine ENS 419972005-09-17T16:29:00017 September 2005 16:29:00 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 Maintenance ENS 418962005-08-05T22:08:0005 August 2005 22:08:00 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 Rps Actuation Due to Low Reactor Water Level Caused by Loss of Reactor Feed Pumps ENS 414042005-02-11T22:29:00011 February 2005 22:29:00 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 a Load Rejection ENS 412192004-11-23T16:02:00023 November 2004 16:02:00 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 Trip ENS 408622004-07-11T03:35:00011 July 2004 03:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram Due to an Upscale Trip on Intermediate Range Monitors ENS 408582004-07-09T03:32:0009 July 2004 03:32:00 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 a Turbine Generator Load Rejection Signal 2023-05-20T08:15:00 | |
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