ENS 48221
ENS Event | |
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12:01 Aug 22, 2012 | |
Title | Automatic Reactor Trip Due to High Reactor Coolant System Pressure |
Event Description | On August 22, 2012, during a planned load reduction, Three Mile Island Unit 1 Reactor automatically tripped at 0801 EDT due to high reactor coolant system pressure as a result of a main feedwater transient. The cause of the main feedwater transient is still under investigation. The Emergency Feedwater System (EFW) actuated at 0801 EDT.
The electrical grid is stable and Unit 1 is being supplied by offsite power. All control rods fully inserted. Decay heat is being removed via the Emergency Feedwater System (EFW) flow to both Steam Generators that are exhausting via the normal main condenser cooling loop under manual control. Preliminary evaluation indicates all plant systems functioned normally following the reactor trip and EFW actuation except for manual operation of Turbine Bypass Valve control due to failure of the automatic control function. Three Mile Island Unit 1 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 (4) hour reports. This event is also reportable under 10 CFR 50.72(b)(3)(iv)(A) and 10 CFR 50.72(b)(3)(iv)(B), due to a valid actuation of the Emergency Feedwater System. The licensee notified the NRC Resident Inspector." Licensee notified the State, local and other Government agencies. |
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 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
LER: | 05000289/LER-2012-004 |
Time - Person (Reporting Time:+-0.48 h-0.02 days <br />-0.00286 weeks <br />-6.57504e-4 months <br />) | |
Opened: | Kevin Coughlin 11:32 Aug 22, 2012 |
NRC Officer: | Dong Park |
Last Updated: | Aug 22, 2012 |
48221 - NRC Website
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Unit 1 | |
---|---|
Reactor critical | Critical |
Scram | A/R |
Before | Power Operation (30 %) |
After | Hot Shutdown (0 %) |
Three Mile Island ![]() | |
WEEKMONTHYEARENS 565602023-06-06T13:37:0006 June 2023 13:37:00
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