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| Entered date | Event description | |
|---|---|---|
| ENS 57021 | 11 March 2024 15:46:00 | The following information was provided by the licensee via phone and email: On March 11, 2024, at 1337 EDT, with Unit 1 in Mode 1 at 35 percent power performing power ascension activities, the reactor was manually tripped due to the 'A' reactor feed pump (RFP) tripping on low suction pressure. Due to the power level at the time, the 'B' RFP had not been placed in service. Closure of containment isolation valves (CIVs) in multiple systems and actuation of high-pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) occurred as a result of reaching the actuation setpoint on reactor water level as designed. The trip was not complex, with all safety systems responding normally post-trip. Operations responded and stabilized the plant. The 'B' RFP was placed in service and is controlling reactor water level. Decay heat is being removed by discharging steam to the main condenser using turbine bypass valves. Unit 2 is not affected. Due to the emergency core cooling system (ECCS) discharging into the reactor, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(A). Also, the Reactor Protection System actuation while critical is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B). Additionally, it is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of CIVs, RCIC and HPCI. There was no impact on the health and safety of the public or plant personnel. The NRC resident inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The cause of the 'A' RFP is under investigation. The reactor electric plant remains in a normal lineup with both emergency diesel generators available. There were no temperature or pressure technical specification limits approached. |
| ENS 56959 | 11 February 2024 11:38:00 | The following information was provided by the licensee via email: At 1011 EST on 02/11/2024, during a refueling outage at 0 percent power, while performing local leakage rate testing (LLRT) of the feedwater check valves (part of the containment boundary), it was determined that the Unit 1 primary containment leakage rate did not meet 10 CFR 50 Appendix J requirements specified in Technical Specification 5.5.12. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
| ENS 52818 | 22 June 2017 09:32:00 | On April 27, 2017 at 0029 EDT, Unit 2 received an invalid partial Group 2 isolation due to a failed relay (2D11-K80) on the auxiliary trip unit. Both of the U1 and U2 Standby Gas Treatment (SGT) trains started and the U2 Group II primary containment and all secondary containment inboard isolation valves closed. Also, the refuel floor isolation dampers closed, the reactor building supply and exhaust fans tripped, and the refueling floor supply and exhaust fans tripped. This event is reportable per 10 CFR 50.73(a)(2)(iv)(A) since the containment isolation and auto-start of SGT on both units was not part of a pre-planned sequence and the event resulted in the invalid actuation of general containment isolation valves in more than one system. All primary and secondary containment inboard isolation valves and SGT systems functioned successfully. The failed relay was replaced and the systems were restored to normal alignment. The licensee will notify the NRC Resident Inspector. |
| ENS 52526 | 1 February 2017 16:46:00 | Plant Hatch declared a notification of unusual event. Subsequent investigation determined the paraphernalia was related to plant drills. The Unusual Event was terminated at 1727 EST. The licensee notified the NRC Resident Inspector. Notified the DHS SWO, FEMA, NICC, and NNSA (via e-mail).
The event was retracted. The licensee notified the NRC Resident Inspector. Notified the R2DO (Shakur), NSIR (Holian), IRD MOC (Gott), DHS SWO, FEMA, NICC, and NNSA (via e-mail). |
| ENS 50072 | 30 April 2014 08:09:00 | On April 30, 2014, at 0800 EDT, the Technical Support Center (TSC) will be unavailable due to pre-planned maintenance on a motor control center associated with the TSC. The TSC is expected to be restored to a functional status in approximately 13 hours. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures, and the TSC staff will relocate to an alternate TSC location in accordance with the Hatch emergency plan and applicable site procedures. This notification is being made in accordance with 10CFR 50.72 (b)(3)(xiii) due to the planned loss of an emergency response facility (ERF). An update will be provided once the TSC has been restored to normal operation. The NRC Resident Inspector has been notified.
The planned maintenance activities have been completed. The power was restored to the TSC at 1802 EDT on 4/30/14. Ventilation has been confirmed to be functional. The TSC was fully functional at 1802 EDT on 04/30/14. The licensee has notified the NRC Resident Inspector. Notified R2DO (Ayres). |
| ENS 48738 | 10 February 2013 09:11:00 | During normal power operations, the crew observed condensate/feedwater conductivity begin to increase at approximately 0530 EST on 02/10/13. The crew responded to the associated alarm response procedures and entered abnormal operating procedure 34AB-N61-001-1 due to degrading reactor water chemistry parameters. A power reduction (from 100%) was initiated at 0555 EST in accordance with station procedures for responding to a suspected condenser tube leak. At 0700 EST, a manual reactor SCRAM (from approximately 47%) was inserted due to the elevated reactor water conductivity in accordance with station abnormal operating procedures. All rods inserted completely and no complications were encountered following the reactor SCRAM, normal feedwater injection remained available. Following the SCRAM, a Group 2 Primary Containment Isolation Signal (PCIS) was received as a result of reactor water level lowering below +3 inches. The lowest reactor water level observed was (minus) 2 inches and was restored to normal operating levels utilizing normal feedwater injection. Following restoration of reactor water level to the normal operating level, the Group 2 PCIS signal was reset. No ECCS injection systems actuated as a result of the reactor SCRAM. The SCRAM was uncomplicated and the plant is stable. Decay heat removal is to the main condenser via the turbine bypass valves. The plant is in a normal offsite electrical power shutdown alignment. Efforts are in progress to isolate the condenser in-leakage. There was no impact on Unit 2. The licensee has notified the NRC Resident Inspector. |