ENS 53953
ENS Event | |
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05:59 Mar 24, 2019 | |
Title | Manual Reactor Scram Due to Degrading Condenser Vacuum |
Event Description | At 0159 [EDT], with Unit 2 in Mode 1 at 25 percent power, the reactor was manually tripped due to degrading condenser vacuum. After the turbine was tripped, the station service electrical buses did not transfer to alternate supply resulting in loss of the condensate feedwater system and level being controlled by the RCIC system.
Operators responded and stabilized the plant. Reactor water level is being maintained via the RCIC system. Pressure is being controlled and decay heat is being removed by the HPCI system in pressure control mode. Unit 1 is not affected. Additionally, an actuation of the primary containment isolation system occurred during the reactor scram. The reason for the actuation was a group II isolation signal was received on reactor water level and a group I isolation was received on decreasing vacuum. Due to the Reactor Protection System actuation while critical, this event is being reported as a four-hour, non- emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Additionally, this event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the primary containment isolation system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
Where | |
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Hatch Georgia (NRC Region 2) | |
Reporting | |
10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
Time - Person (Reporting Time:+-0.6 h-0.025 days <br />-0.00357 weeks <br />-8.2188e-4 months <br />) | |
Opened: | Russell Lewis 05:23 Mar 24, 2019 |
NRC Officer: | Mark Abramovitz |
Last Updated: | Mar 24, 2019 |
53953 - NRC Website
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Unit 2 | |
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Reactor critical | Critical |
Scram | Yes, Manual Scram |
Before | Power Operation (25 %) |
After | Hot Shutdown (0 %) |
Hatch with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 573432024-09-27T07:46:00027 September 2024 07:46:00
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ECCS Discharge Manual Reactor Scram After Feed Pump Trip ENS 443372008-07-04T12:39:0004 July 2008 12:39:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Reactor Scram on Turbine Trip ENS 440462008-03-07T19:46:0007 March 2008 19:46:00 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 Scram with Hpci/Rcic Actuation Due to Loss of Condensate Feedwater ENS 435522007-08-07T19:06:0007 August 2007 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 Scram on Low Reactor Water Level Following Partial Loss of Condensate Feedwater Flow ENS 424712006-04-05T04:16:0005 April 2006 04:16:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Reactor Scram Following Main Turbine Control Valve Fast Closure ENS 420962005-10-29T17:25:00029 October 2005 17:25:00 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 Unusual Event - Main Transformer Fire ENS 417252005-05-23T21:47:00023 May 2005 21:47:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Manual Scram Due to Condenser Hotwell Chemistry ENS 410702004-09-25T05:06:00025 September 2004 05:06:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Group 2 Containment Isolation Actuation ENS 405652004-03-03T18:45:0003 March 2004 18:45:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Swing Diesel Generator Auto Started from a Bus Undervoltage Valid Signal 2024-09-27T07:46:00 | |