ENS 44627
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ENS Event | |
|---|---|
04:22 Nov 4, 2008 | |
| Title | Manual Reactor Trip Due to Feedwater Reg Valve Failure |
| Event Description | On 11/3/08 at 2322, Unit 2 was manually tripped due to the failure of Loop 4 Feed Water Reg. Valve (FRV Controller). Manual control was attempted to control level in Loop 4 Steam Generator (S/G); however, Loop 4 FRV failed to respond. A manual Reactor Trip was initiated as a result of this failure. In addition, Auxiliary Feedwater (AFW) initiated as required due to a Feedwater isolation signal
The Loop 4 FRV did isolate from the Feedwater isolation signal. The Plant is being maintained in Mode 3 at NOT/NOP, 547 F and 2235 psig, with AFW supplying the S/G's and Steam Dumps removing decay heat. Additionally, Unit 2 has an indication of a primary leak inside lower containment. The leak rate is calculated to be approximately 2.0 gallons per minute. Based on current indications, the leak is suspected to be from a Pressurizer level transmitter No primary system or steam generator safety valves opened due to this trip. An investigation has been initiated to determine the cause of the Loop 4 Feed Water Reg. Valve (FRV Controller) failure and the source of the approximately 2.0 gallons per minute primary leak. A recovery plan will be developed. Pressurizer (PRZ) level is stable. All safety related systems are available and OPERABLE for safe plant shutdown. There is no impact on Unit 1. The loop 2 S/G blowdown sample line valve did not go closed as expected on the Feedwater isolation signal. The licensee is taking action to isolate it. The licensee notified the NRC Resident Inspector.
The Sequoyah Nuclear Plant Unit - 2 reactor coolant system unidentified leakage was terminated on Nov. 4, 2008 @ 2205 hours0.0255 days <br />0.613 hours <br />0.00365 weeks <br />8.390025e-4 months <br /> when a manual valve was closed isolating the reactor coolant system from the leak location." The licensee closed the root valve to the PZR pressure channel 2-VLV-68-446A. The licensee will notify the NRC Resident Inspector. Notified R2DO(Desai) |
| Where | |
|---|---|
Sequoyah  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-1.4 h-0.0583 days <br />-0.00833 weeks <br />-0.00192 months <br />) | |
| Opened: | Julious Whitworth 02:58 Nov 4, 2008 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Nov 5, 2008 |
| 44627 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | Yes, Manual Scram |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 573512024-09-29T09:56:00029 September 2024 09:56:00
[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 Turbine Trip ENS 572852024-08-23T16:19:00023 August 2024 16:19:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip ENS 572532024-07-30T20:41:00030 July 2024 20:41:00 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 552722021-05-24T13:16:00024 May 2021 13:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation on 5/24/21 at 0916 Edt, an Automatic Reactor Trip on Unit 1 Occurred. All Safety Systems Responded Normally and the Plant Is Currently Stable in Mode 3 (Hot Standby) at Normal Operating Temperature and Pressure. Preliminary Indications Are That the Unit Trip Was Caused by a High Neutron Flux Rate Detected by the Power Range Nuclear Instruments. Troubleshooting and Investigation Are Ongoing to Determine the Initiating Cause. ENS 544382019-12-12T09:33:00012 December 2019 09:33:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation ENS 542422019-08-27T05:09:00027 August 2019 05:09:00 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 539992019-04-14T07:20:00014 April 2019 07:20:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation En Revision Imported Date 8/7/2019 ENS 515592015-11-23T13:44:00023 November 2015 13:44:00 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 Partial Msiv Closure ENS 513922015-09-14T08:26:00014 September 2015 08:26:00 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 Loss of Power to Vital Instrument Board ENS 512652015-07-27T14:43:00027 July 2015 14:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor/Turbine Trip ENS 512592015-07-24T17:51:00024 July 2015 17:51:00 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 on Main Generator Lockout ENS 508782015-03-11T10:21:00011 March 2015 10:21:00 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 a Nuclear Instrumentation Signal ENS 508562015-03-02T11:45:0002 March 2015 11:45:00 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 487782013-02-24T17:05:00024 February 2013 17:05:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Loss of Condenser Vacuum Indication ENS 481982012-08-16T23:26:00016 August 2012 23:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip from a Reactor Coolant Pump Trip ENS 471692011-08-19T02:50:00019 August 2011 02:50:00 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 Reactor Coolant Pump Bus Undervoltage ENS 470812011-07-21T01:29:00021 July 2011 01:29:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Negative Rate Trip Following Rapid Turbine Load Reduction ENS 469912011-06-26T20:14:00026 June 2011 20:14:00 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 464922010-12-20T05:50:00020 December 2010 05:50:00 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 a Fire in the Main Generator Bus Duct ENS 464242010-11-17T03:10:00017 November 2010 03:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Based on Decreasing Steam Generator Level ENS 455202009-11-26T07:42:00026 November 2009 07:42:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Trip Due to Loss of Vacuum on Turbine Driven Feedwater Pump ENS 450972009-05-27T23:04:00027 May 2009 23:04:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip from Power Range High Neutron Flux Rate ENS 450452009-05-07T02:56:0007 May 2009 02:56:00 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 Feed Regulating Valve Failure ENS 450292009-04-29T01:59:00029 April 2009 01:59:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Initiated as a Result of a Loss of Condensate Flow ENS 449352009-03-26T08:52:00026 March 2009 08:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip and Aux Feed Water Start Due to Loss of an Off Site Power Source ENS 449342009-03-26T08:52:00026 March 2009 08:52:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip and Aux Feed Water Start Due to Loss of an Off Site Power Source ENS 446272008-11-04T04:22:0004 November 2008 04:22:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Reactor Trip Due to Feedwater Reg Valve Failure ENS 439092008-01-17T00:25:00017 January 2008 00:25:00 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 Lowering Steam Generator Level ENS 432332007-03-13T19:27:00013 March 2007 19:27:00 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 "a" Main Feedwater Pump ENS 431152007-01-23T17:44:00023 January 2007 17:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip Due to Feedwater Regulating Valve Failure ENS 424442006-03-22T21:24:00022 March 2006 21:24:00 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 Caused by Main Generator Trip ENS 415832005-04-09T15:11:0009 April 2005 15:11:00 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 Due to Low Auto Stop Oil Pressure on Pressure Switches ENS 414372005-02-24T02:06:00024 February 2005 02:06:00 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 Low-Low Steam Generator Level ENS 405892004-03-15T20:18:00015 March 2004 20:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Main Generator Electrical Fault Signal ENS 401132003-08-28T20:04:00028 August 2003 20:04:00 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 Alert Declared Due to Reactor Protection System Failure 2024-09-29T09:56:00 | |
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