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| Entered date | Event description | |
|---|---|---|
| ENS 55272 | 24 May 2021 12:01:00 | Unit 2 is not impacted and remains stable in Mode 1 at 100 percent power. 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) and in accordance with 10 CFR 50.72 (b)(3)(iv)(A) as an event that results in a valid actuation of the AFW system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. No relief valves opened. All Rods fully inserted. Decay heat is being removed by Auxiliary Feedwater via the steam dumps. The plant is in a normal post-trip electrical line-up. |
| ENS 50856 | 2 March 2015 10:22:00 | At 06:45 EST on 3/2/2015, Sequoyah Unit 2 reactor/turbine automatically tripped. Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal. Unit 2 is currently being maintained in Mode 3 at NOT/NOP (normal operating temperature and pressure), approximately 548 F and 2235 psig, with auxiliary feedwater supplying decay heat removal via the steam generators and condenser steam dumps. The immediate cause of the trip was a main generator C phase differential relay actuation. There was no associated work in progress related to this and all systems were normally aligned. It is currently not understood why the relay actuated. Current Temperature and Pressure - temperature is 548 degrees F and stable, pressure is 2235 psig and stable. There is no indication of any primary/secondary leakage. All rods are inserted. Electrical alignment is normal, supplied from Off-Site power. The 2B Emergency Diesel Generator is currently unavailable for planned maintenance and will be returned to service prior to unit restart. There is no operational impact to Unit 1. Unit 1 continues to operate in Mode 1 at 100%. There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined. The licensee notified the NRC Resident Inspector" and the state. No primary or secondary safety valves lifted during this event. |