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| Entered date | Event description | |
|---|---|---|
| ENS 56116 | 19 September 2022 08:37:00 | The following information was provided by the licensee via email: At 0132 CDT on September 19, 2022, River Bend Station (RBS) was operating at 100% power when the high pressure core spray (HPCS) system was declared inoperable in accordance with technical specification 3.8.9, condition E (declare HPCS and standby service water system pump 2C inoperable immediately) due to a E22-S003, HPCS transformer feeder malfunction. The HPCS is a single train system at RBS, therefore this event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfilment of a safety function. The reactor core isolation cooling system has been verified to be operable. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: RBS has entered a 14-day limiting condition for operation due to the loss of HPCS and they have upgraded their on-line plant risk model to "yellow". |
| ENS 55154 | 25 March 2021 13:37:00 | On March 25, 2021 at 0901 CDT, River Bend Station Unit 1 (RBS) was operating at 93 (percent) reactor power (limited by 100 (percent) recirculation flow) when condenser vacuum began to lower due to ARC-AOV1A, Steam Jet Air Ejector Suction Valve, going closed. At 0918 CDT, a manual reactor SCRAM was inserted at approximately 80 (percent) reactor power due to condenser vacuum continuing to lower. After the SCRAM, all systems responded as designed and condenser vacuum was restored by starting a mechanical vacuum pump. The cause of the Steam Jet Air Ejector Suction Valve closure is unknown at this time and being investigated. Currently RBS is stable, and pressure is being maintained using Turbine Bypass Valves. The Main Steam Isolation Valves remained opened throughout the event. This event is being reported under 10 CFR 50.72(b)(2)(iv)(B), as any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical and 10 CFR 50.72 (b)(3)(iv)(A) Specified System Actuation as result of expected post SCRAM level 3 isolations. No radiological releases have occurred due to this event from the unit. NRC Resident Inspector has been notified of this event. |
| ENS 54991 | 10 November 2020 22:06:00 | On November 10, 2020, at 1827 CST, River Bend Station (RBS) received a report of a single inadvertent and malfunctioning siren which is part of the Emergency Notification System. The siren was heard by residences in the area and they contacted local agencies, who in turn contacted RBS. This siren activation was not related to any condition or event and no emergency has occurred at RBS. RBS has notified the appropriate authorities and the Governor's Office of Homeland Security and Emergency Preparedness of the inadvertent siren activation. RBS has sent a team to locally disable the siren to prevent any further inadvertent sounding and it is now disabled. A press release from Entergy is not planned at this time. The NRC resident has been notified of the event. The licensee also notified the East and West Feliciana Parish Authorities. If an emergency notification were required, there is overlap of working sirens to cover the area of the siren that is out of service. |
| ENS 54121 | 17 June 2019 12:56:00 | This 60-day telephone notification is being made in accordance with the reporting requirements specified by 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to describe an invalid actuation of a general containment isolation signal affecting multiple systems. On April 30, 2019, at approximately 0650 CDT, a level 2 containment isolation signal was introduced when a fuse for the Nuclear Steam Supply Shutoff System was removed for a maintenance clearance. The level 2 containment isolation signal caused a trip of the Division I DC bus back-up charger, leaving only the Division I battery to carry the DC bus. At 0707 CDT the bus was de-energized when another unrelated clearance opened the battery supply breaker to the DC bus causing another containment isolation signal. This event did not affect Shutdown Cooling or any other protected Safety Related Equipment. The containment isolation signals caused an isolation of the systems listed below. All components that were not removed from service, gagged in position, already in the expected position due to plant conditions, or de-energized due to plant condition performed as designed. Containment Isolation valves for the following systems isolated as expected: Drywell and Containment Floor Drains, Drywell and Containment Equipment Drains, Condensate Makeup, Fire Protection Water, Service Air, Instrument Air, Reactor Water Cleanup, Spent Fuel Cooling and Cleanup, Reactor Plant Component Cooling Water, Chilled Water, Reactor Recirculation, Main Steam Drains, Reactor Building Ventilation, and Fuel Building Ventilation. The licensee notified the NRC Resident Inspector. |