ENS 42569
ENS Event | |
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19:14 May 11, 2006 | |
Title | Manual Actuation of Reactor Protection System Due to Failure of Control Rod to Withdraw |
Event Description | Following a startup from a refueling outage with the plant at approximately 24% power, it was determined that one control rod appeared to be fully inserted in the core as determined by both incore and excore flux tilts. The Off Normal Procedure for a dropped control rod was entered. The decision was made to take the plant offline to troubleshoot and correct the apparent condition. The Off Normal Procedure does not allow operation in Mode 2 with a dropped control rod. At 1514 hours0.0175 days <br />0.421 hours <br />0.0025 weeks <br />5.76077e-4 months <br /> EDT the reactor was manually tripped from 8% power. The reactor trip was uncomplicated.
This is reportable under 10 CFR 50.72(b)(2)(iv)(B) as a manual Reactor Protection System actuation while critical. Decay heat is being discharged to the condenser via the turbine bypass valves and cooling is being supplied from AFW. All systems besides the control rod in question functioned as required. It appears that the control rod in question may have been inserted since startup. The rod position indicators were showing a normal rod position. The licensee believes that the rod may not be coupled. This rod has had a previous history of being difficult to couple. The licensee stated that normal rod testing was conducted prior to startup along with low power physics testing which did not indicate anything significantly out of spec. The licensee notified the NRC Resident Inspector. |
Where | |
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Palisades Michigan (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
Time - Person (Reporting Time:+-1.65 h-0.0688 days <br />-0.00982 weeks <br />-0.00226 months <br />) | |
Opened: | Patrick Pitcher 17:35 May 11, 2006 |
NRC Officer: | Bill Huffman |
Last Updated: | May 11, 2006 |
42569 - NRC Website
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Unit 1 | |
---|---|
Reactor critical | Critical |
Scram | Yes, Manual Scram |
Before | Power Operation (8 %) |
After | Hot Standby (0 %) |
WEEKMONTHYEARENS 538192019-01-09T05:00:0009 January 2019 05:00:00
[Table view]10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Reactor Trip from Full Power Due to Rps Testing ENS 538132019-01-03T05:00:0003 January 2019 05:00:00 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 Cycling of Turbine Governor Valve ENS 513972015-09-16T05:17:00016 September 2015 05:17:00 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 475232011-12-14T20:10:00014 December 2011 20:10:00 Other Unspec Reqmnt, 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 Both Main Feedpumps ENS 472902011-09-25T19:06:00025 September 2011 19:06:00 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 Loss of Two 120 Volt Ac Instrument Busses ENS 465642011-01-22T22:35:00022 January 2011 22:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Trip Due to Loss of Generator Load ENS 442372008-05-23T16:49:00023 May 2008 16:49:00 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 Possible Generator Lockout ENS 439002008-01-13T10:21:00013 January 2008 10:21:00 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 Loss of Main Feedwater Pump ENS 433512007-05-08T17:22:0008 May 2007 17:22:00 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 Steam Generator Water Level ENS 425692006-05-11T19:14:00011 May 2006 19:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Manual Actuation of Reactor Protection System Due to Failure of Control Rod to Withdraw ENS 419672005-09-01T14:25:0001 September 2005 14:25:00 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 Main Generator Hydrogen Leak ENS 413192005-01-09T16:27:0009 January 2005 16:27:00 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 Lowering Main Condenser Vacuum ENS 410022004-08-31T11:18:00031 August 2004 11:18:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Rps Actuation Due to Fire in 2B Condensate Pump 2019-01-09T05:00:00 | |