ENS 42942
From kanterella
Jump to navigation
Jump to search
ENS Event | |
|---|---|
16:23 Oct 28, 2006 | |
| Title | Specified System Actuation |
| Event Description | During plant cooldown/depressurization in Mode 3, an Over Temperature (OT) Delta Temperature reactor trip signal was generated. The reactor Trip Breakers opened as designed (all rods were previously inserted). Additionally, a low Tavg/P-4 Feedwater Isolation Signal was generated and all Bypass Feedwater Regulation Valves closed (open for long-cycle recirculation operation). No Feedwater Isolation Valves were open at the time. All systems performed as designed.
Actual loop Delta T's (Th - Tc) never exceeded 3.3 degrees F, well below the calculated OT Delta T setpoint. But plant Delta T calculations are based on narrow range Th and Tc instruments with scaling to low limits. When actual plant temperature was lowered to the lower limits of each instrument, calculated Delta T increased to the OT Delta T setpoint causing the reactor trip signal. Existing procedure guidance did not adequately ensure that the reactor trip breakers are open prior to initiating a partial plant cooldown. The plant was stabilized. The long-cycle recirculation was re-established and plant cooldown/depressurization was recommenced, as originally planned to 340 degrees F and 925 psig. The licensee notified the NRC Resident Inspector.
Alvin W. Vogtle, Unit 1, Operating License no. NPF-68, Event Notification #42942 is retracted. The event reported in the notification which occurred during the Unit 1 cooldown in Mode 3 was not representative of the conditions under which the Over Temperature Delta Temperature (OTDT) setpoint is intended to operate. The setpoint is intended to provide protection while the reactor is in Modes 1 and 2. As the cooldown progressed from Normal Operating Pressure and Temperature (NOPT), eventually the Reactor Coolant System (RCS) hot and cold leg temperature indications reached the low end of their ranges or scales. Further reductions of temperature resulted in artificial indications of core power (delta-T) that cannot be relied upon as a valid input to the OTDT protective function. The actuation of the Reactor Protection System (RPS) is not considered to be a valid actuation. As such, this is not reportable under 10 CFR 50.72(b)(3)(iv)(A). The Unit 1 Feedwater Isolation caused from the OTDT reactor trip is not a function is listed in 10 CFR 50.72(b) (3)(iv)(B) as a system whose actuation is required to be reported under 10 CFR 50.72(b)(3)(iv)(A). The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Vogtle  Georgia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-0.35 h-0.0146 days <br />-0.00208 weeks <br />-4.7943e-4 months <br />) | |
| Opened: | Mark Slivka 16:02 Oct 28, 2006 |
| NRC Officer: | Bill Gott |
| Last Updated: | Nov 9, 2006 |
| 42942 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Standby (0 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 563112023-01-14T12:21:00014 January 2023 12:21:00
[Table view]10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Actuation of Reactor Protection System (RPS) ENS 562942023-01-04T03:59:0004 January 2023 03:59:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of Offsite Power Source ENS 561472022-10-06T06:44:0006 October 2022 06:44:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of Reactor Protection System (RPS) ENS 558752022-05-03T19:41:0003 May 2022 19:41:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip and Automatic Actuation of Auxiliary Feedwater System ENS 545962020-03-21T20:44:00021 March 2020 20:44:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of the 1B Emergency Diesel Generator ENS 543182019-10-09T14:23:0009 October 2019 14:23:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of Emergency Diesel Generator and Auxilliary Feedwater System ENS 541752019-07-19T13:45:00019 July 2019 13:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Main Steam Isolation Valve Failing Shut ENS 539672019-03-31T01:30:00031 March 2019 01:30:00 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 Msiv Failing Closed ENS 536432018-10-04T04:00:0004 October 2018 04:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation En Revision Imported Date 10/22/2018 ENS 534842018-07-03T04:00:0003 July 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 Manual Reactor Trip Due to High Steam Generator Water Level ENS 529922017-09-26T09:43:00026 September 2017 09:43:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Start of the 2B Emergency Diesel Due to a Valid Undervoltage Signal ENS 526192017-03-17T19:17:00017 March 2017 19:17:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Actuation of Emergency Diesel Generator ENS 525342017-02-03T20:45:0003 February 2017 20:45:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Manual Reactor Trip Due to Loop 1 Msiv Starting to Fail Closed ENS 519562016-05-25T06:06:00025 May 2016 06:06:00 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 Lowering Steam Generator Water Level ENS 508942015-03-14T16:07:00014 March 2015 16:07:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Actuation During Surveillance Test ENS 508932015-03-14T08:29:00014 March 2015 08:29:00 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 Reactor Trip on System Injection Actuation Signal ENS 503142014-07-27T18:09:00027 July 2014 18:09:00 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 Main Feed Pump During Testing ENS 500312014-04-13T00:08:00013 April 2014 00:08:00 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 Main Steam Isolation Valve Failing Shut ENS 500062014-04-08T08:28:0008 April 2014 08:28:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Low Steam Generator Level ENS 494612013-10-22T15:44:00022 October 2013 15:44:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Decreasing Condenser Vacuum ENS 494532013-10-19T10:43:00019 October 2013 10:43:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Turbine Trip ENS 487882013-02-27T04:02:00027 February 2013 04:02:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip Due to Excessive Reactor Coolant Pump Seal Leakoff Flow ENS 483852012-10-05T09:14:0005 October 2012 09:14:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unplanned Auxiliary Feedwater Actuation ENS 478362012-04-14T17:46:00014 April 2012 17:46:00 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 Low Main Feedwater Flow ENS 472242011-08-31T13:06:00031 August 2011 13:06:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Turbine Trip on Hi-Hi Steam Generator Level Results in Automatic Reactor Trip ENS 467722011-04-20T21:34:00020 April 2011 21:34:00 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 455882009-12-23T20:25:00023 December 2009 20:25:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Rps Actuation Due to Loss of Instrument Air ENS 455572009-12-10T04:10:00010 December 2009 04:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Following High Turbine Vibration ENS 455472009-12-07T23:01:0007 December 2009 23:01:00 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 Turbine Trip Caused by Low Condenser Vacuum ENS 433132007-04-23T14:24:00023 April 2007 14:24:00 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 Generator Ground Relay Actuation ENS 429422006-10-28T16:23:00028 October 2006 16:23:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Specified System Actuation ENS 428062006-08-27T10:31:00027 August 2006 10:31:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Reactor Coolant Pump Trip ENS 425062006-04-17T04:26:00017 April 2006 04:26:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Manually Tripped Due to Failure of a Main Feed Regulating Valve to Control Steam Generator Level ENS 420582005-10-17T22:16:00017 October 2005 22:16:00 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 Low Steam Generator Level ENS 416532005-04-30T01:55:00030 April 2005 01:55:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Reactor Trip - Lowering Steam Generator Level on Loop #1 ENS 413232005-01-11T12:19:00011 January 2005 12:19:00 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 Main Turbine Trip ENS 412132004-11-20T16:40:00020 November 2004 16:40:00 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 Unexpected Automatic Reactor Trip During Surveillance Testing with Si Injection ENS 406822004-04-18T16:38:00018 April 2004 16:38:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Auxiliary Feedwater System Actuation Due to Main Feed Pump Trips ENS 406152004-03-28T03:05:00028 March 2004 03:05:00 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 Feedwater Pump Speed Control ENS 402682003-10-22T05:03:00022 October 2003 05:03:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation High Pressure Hose Connection Failed Resulting in a Train "a" Manual Steam Line Isolation 2023-01-04T03:59:00 | |
Retrieved from "https://kanterella.com/w/index.php?title=ENS_42942&oldid=91290"