ENS 48325
ENS Event | |
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18:16 Sep 20, 2012 | |
Title | Automatic Reactor Trip Due to Reactor Protection System Actuation |
Event Description | On September 20th at 1416 EDT, Three Mile Island automatically tripped due to a flux to flow imbalance as a result of a trip of the 'C' reactor coolant pump. The cause of the trip of the 'C' reactor coolant pump is still under investigation.
The electrical grid is stable and unit 1 is being supplied by offsite power. All control rods have fully inserted. Decay heat is being removed by main feedwater flow to both steam generators that are exhausting via the normal main condenser cooling loop under manual control. Preliminary evaluation indicates that all plant systems functioned normally following the reactor trip, except for automatic operation of turbine bypass valve control due to failure of the automatic control function to control precisely at setpoint. Three Mile Island remains stable in hot shutdown mode while conducting the post trip review. No radioactive releases were experienced as a result of this event. This event is reportable under 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation, and under 10 CFR 50.72 (b)(2)(xi) due to an information release to local officials. Both are four hour reports. The licensee notified the NRC Resident Inspector." The licensee has notified the state and local governments, and will be making a media release. |
Where | |
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Three Mile Island Pennsylvania (NRC Region 1) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | |
Time - Person (Reporting Time:+-2.02 h-0.0842 days <br />-0.012 weeks <br />-0.00277 months <br />) | |
Opened: | David Lewis 16:15 Sep 20, 2012 |
NRC Officer: | John Knoke |
Last Updated: | Sep 20, 2012 |
48325 - NRC Website
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Unit 1 | |
---|---|
Reactor critical | Critical |
Scram | A/R |
Before | Power Operation (100 %) |
After | Hot Shutdown (0 %) |
Three Mile Island with 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | |
WEEKMONTHYEARENS 565602023-06-06T13:37:0006 June 2023 13:37:00
[Table view]10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification Due to ON-SITE Fatality ENS 554552021-09-10T14:55:00010 September 2021 14:55:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 72.75(b)(2), Offsite Notification Offsite Notification Due to Contractor Fatality ENS 542832019-09-17T14:28:00017 September 2019 14:28:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release On-Site Non-Work Related Fatality ENS 533232018-04-11T09:42:00011 April 2018 09:42:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification Due to Hydrazine Spill ENS 529272017-08-25T15:15:00025 August 2017 15:15:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification Due to Exceeding Chlorine Effluent Limit ENS 506542014-12-04T16:50:0004 December 2014 16:50:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification Due to Emergency Siren Inadvertently Sounding ENS 483252012-09-20T18:16:00020 September 2012 18:16:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Trip Due to Reactor Protection System Actuation ENS 482212012-08-22T12:01:00022 August 2012 12:01:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 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 High Reactor Coolant System Pressure ENS 481322012-07-25T18:30:00025 July 2012 18:30:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Press Release Due to an Elevated Level of Tritium Detected on Site ENS 470482011-07-14T17:19:00014 July 2011 17:19:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification Due to Inadvertant Siren Actuation ENS 455142009-11-22T03:45:00022 November 2009 03:45:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Radiation Release in Containment Associated with Steam Generator Removal ENS 430502006-12-13T22:48:00013 December 2006 22:48:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Unit Reactor Trip Due to Grid Disturbance ENS 429572006-11-02T18:34:0002 November 2006 18:34:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Turbine Trip/ Reactor Trip Due to Invalid Low Condenser Vacuum Signal ENS 402442003-10-13T15:20:00013 October 2003 15:20:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release Offsite Notification to Osha at Three Mile Island Regarding a Fatality ENS 401782003-09-19T06:24:00019 September 2003 06:24:00 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Loss of Emergency Siren Capability Due to Adverse Weather Conditions 2023-06-06T13:37:00 | |