The Main Transformer goes from main generator to grid
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| | Site | Start date | Title | Description |
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| IR 05000387/2025003 | Susquehanna | 22 December 2025 | Integrated Inspection Report 05000387/2025003 and 05000388/2025003, Independent Spent Fuel Storage Installation IR 07200028/2024001 and 07200028/2025001, and Exercise of Enforcement Discretion | | | IR 05000346/2025003 | Davis Besse | 22 December 2025 | Integrated Inspection Report 05000346/2025003 07200014/2025001 and Exercise of Enforcement Discretion | | | 05000482/LER-2025-003, Loss of Voltage on ESF Bus Results in Automatic Actuation of Emergency Diesel Generator | Wolf Creek | 17 December 2025 | Loss of Voltage on ESF Bus Results in Automatic Actuation of Emergency Diesel Generator | | | IR 05000382/2025003 | Waterford | 17 December 2025 | Integrated Inspection Report 05000382/2025003 | | | ML25342A446 | Salem | 15 December 2025 | Regulatory Audit Summary in Support of the NRC Staffs Review of LARs to Adopt TSTF-505 and 10 CFR 50.69 | | | ENS 58054 | South Texas | 21 November 2025 18:08:00 | Automatic Reactor Trip | The following information was provided by the licensee via phone and email:
At 1208 CST on 11/21/2025, with Unit 2 in Mode 1 at 100 percent power, (the) Unit 2 reactor automatically tripped due to a main transformer lockout. The trip was not complex, with all systems responding normally post-trip. One of three essential chillers (chiller 22C) was inoperable at the time of (the) trip due to planned maintenance activities. All other engineered safety feature (ESF) equipment was operable at the time of the event.
Operations responded and stabilized the plant. Decay heat is being removed by steam generator pressure operated relief valves (PORV). There was no impact to Unit 1.
All control rods fully inserted.
Primary pressurizer PORV '655A' opened twice to relieve pressure in response to (the) pressure transient.
(South Texas Project Unit 2) entered Technical Specification 3.8.1.1.e due to a loss of two off-site power sources, `A' and `C' ESF busses.
Upon main turbine trip, throttle valves closed as expected.
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).
This event is also being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) due to valid actuation of two of the three emergency diesel generators.
There was no impact on the health and safety of the public or plant personnel, and Unit 2 remains at normal operating temperature and normal operating pressure.
The NRC Resident Inspector has been notified.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
Emergency diesel generators '21' and '23' automatically started upon loss of power as expected. Auxiliary feedwater actuated post-trip as expected. Offsite power to ESF busses has been restored. | | ML25262A143 | Robinson | 14 November 2025 | Aging Management Audit Report - Robinson, Unit 2 SLR | | | 05000387/LER-2025-001-01, (SSES) Unit 1, Manual Reactor Scram Following Loss of Cooling to Main Transformer | Susquehanna | 13 November 2025 | (SSES) Unit 1, Manual Reactor Scram Following Loss of Cooling to Main Transformer | | | ENS 58026 | Wolf Creek | 5 November 2025 16:03:00 | Automatic Emergency Diesel Generator Actuation | The following information was provided by the licensee via phone and email:
At 1003 Central Standard Time (CST), with (Unit 1) in mode 5 at 0 percent power, an actuation of the 'A' emergency diesel generator (EDG) occurred when energizing main transformers from the switchyard for post-installation soak. The energization was coordinated with transmission system operators using approved procedures, however, grid conditions external to the substation allowed the voltage to drop below the NB01 undervoltage relay setpoint. The EDG automatically started as designed and picked up the loads on the NB01 bus. All safety systems responded as designed. Substation parameters immediately recovered to normal values, and all systems were restored to (normal) standby conditions.
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 'A' EDG. There was no impact on the health and safety of the public or plant personnel.
The NRC Resident Inspector has been notified. | | ML25303A293 | Crane | 31 October 2025 | Submittal of Christopher M. Crane Clean Energy Center Environmental Report | |
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