| Site | Start date | Title | Description |
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ENS 57159 | Oconee | 3 June 2024 04:51:00 | Automatic Actuation of Emergency Feedwater System | The following information was provided by the licensee via phone and email:
At 0051 EDT on June 3, 2024, with Unit 3 in Mode 3 at 0 percent power, an actuation of the emergency feedwater system (EFW) occurred as main steam pressure was being lowered as part of reactor coolant system (RCS) cooldown for a planned shutdown. The reason for the EFW auto-start was lowering levels in the 3A and 3B steam generators following loss of the operating main feedwater pump. The main feedwater pump automatically tripped when main steam pressure was lowered below the automatic feedwater isolation system (AFIS) actuation setpoint before AFIS channels were taken to bypass. The 3A and 3B motor driven emergency feedwater pumps automatically started as designed when the low steam generator level signal was received for the 3A and 3B steam generators.
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 EFW system.
There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. |
ENS 57158 | Surry | 2 June 2024 21:08:00 | Automatic Reactor Trip | The following information was provided by the licensee via phone and email:
Surry Unit 1 reactor automatically tripped at 1708 EDT on 6/2/24 due to a turbine trip (with the reactor operating at greater than 10 percent reactor power).
The turbine control system is currently under investigation. Reactor coolant temperature is being maintained via main steam dumps with main feedwater supplying the steam generators.
All systems operated as required. The trip was uncomplicated and all control rods fully inserted into the core. There was no emergency core cooling system (ECCS) or auxiliary feedwater system actuation. Offsite power remains available. There is no impact to Surry Unit 2.
This notification is being made pursuant to 10 CFR 50.72(b)(2)(iv)(B) for 4-hour notification of reactor protection system activation. The NRC Resident Inspector has been notified.
There were no radiation releases, personnel injuries, or contamination events due to this event. |
ENS 57046 | Fermi | 23 March 2024 04:04:00 | Automatic Reactor Trip | The following information was provided by the licensee via email:
At 0004 EDT on March 23, 2024, with the unit in Mode 1 at 23 percent power, the reactor automatically scrammed due to high reactor pressure vessel pressure when the turbine bypass valves unexpectedly closed while attempting to lower generator MW to 55 MWe to support shutdown for a refueling outage. The scram was not complex, with systems responding normally post-scram, with the exception of the pressure control system. The transient occurred while lowering on turbine speed/load demand which caused a rise in pressure and power until the reactor protection system setpoint for reactor pressure high was exceeded and resulted in an automatic reactor scram. The plant was preparing to shut down for a refueling outage when the trip occurred.
Operations responded and stabilized the plant. Reactor water level is being maintained at normal level. Decay heat is being removed by the main steam system to the main condenser using manual operation of the turbine bypass valves. All control rods inserted into the core.
Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CPR 50.72(b)(2)(iv)(B). Additionally, received expected (primary containment) isolations for Level 3: Group 13 drywell sumps, Group 15 (traverse in-core probe) TlPs (which was already isolated) and Group 4 (residual heat removal - shutdown cooling) RHR-SDC (which was already isolated). The primary containment isolation event is being reported under 10 CFR 50.72(b)(3)(iv)(A). Also, due to the main turbine bypass valves unexpectedly closing, this is also being reported under 10 CFR 50.72(b)(3)(v)(D).
There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
- * * UPDATE ON 4/22/24 AT 1448 EDT FROM WHITNEY HEMINGWAY TO ADAM KOZIOL * * *
The purpose of this notification is to retract the 10 CFR 50.72(b)(3)(v)(D) reporting criteria of event notification 57046 reported on March 23,2024. Based on further evaluation, Fermi 2 has concluded that there was no event or condition that could have prevented fulfillment of a safety function that was needed to mitigate the consequence of an accident. Although discussed in Chapter 15 of the UFSAR, the turbine bypass valves do not provide a safety related function and are not credited safety related components for accident mitigation. Therefore, Fermi 2 is retracting the 10 CFR 50.72(b)(3)(v)(D) reporting criteria that was included on the March 23, 2024 event notification.
Notified R3DO (Betancourt-Roldan) |
ENS 57032 | Waterford | 16 March 2024 19:49:00 | Manual Reactor Trip Due to Main Feedwater and Main Steam Isolations | The following information was provided by the licensee via phone and email:
At 1449 CDT, Waterford 3 Steam Electric Station was operating at 100 percent power when a manual reactor trip was initiated due to main feed isolation valve (FW-184B) and main steam isolation valve (MS-124B) going closed unexpectedly.
Emergency feedwater (EFW) was automatically actuated. Preliminary evaluation indicates that all plant systems functioned normally after the reactor trip. The unit is currently stable in Mode 3. All control rods fully inserted as expected.
This event is being reported as a 4-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the reactor protection system (RPS) when the reactor is critical and as an 8-hour nonemergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as valid actuation of the EFW system.
The NRC Resident Inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Decay heat is being removed through the turbine bypass valves and the atmospheric dump valve on loop '2'. There is no primary to secondary system leakage. The cause of the isolations is still being investigated. |
IR 05000382/2023010 | Waterford | 31 January 2024 | Comprehensive Engineering Team Inspection Report 05000382/2023010 | |
NUREG-2194 Volume 2, Rev. 1, Standard Technical Specifications, Westinghouse Advanced Passive 1000 (AP1000) Plants, Volume 2: Bases | | 31 January 2024 | NUREG-2194, Vol. 2, Rev. 1, Standard Technical Specifications, Westinghouse Advanced Passive 1000 (AP1000) Plants, Volume 2: Bases | |
IR 05000395/2023004 | Summer | 31 January 2024 | Integrated Inspection Report 05000395/2023004 | |
ML23361A157 | Clinton | 24 January 2024 | Audit Plan in Support of Review of License Amendment Request Regarding Revision of Technical Specifications Related to Reactor Water Cleanup Isolation | |
IR 05000483/2023004 | Callaway | 19 January 2024 | Integrated Inspection Report 05000483/2023004 | |
2CAN012403, Supplemental Information - Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4 | Arkansas Nuclear | 11 January 2024 | Supplemental Information - Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4 | |