Event Notification Report for October 22, 2025

BOTH TRAINS OF CONTROL ROOM EMERGENCY VENTILATION SYSTEM INOPERABLE

The following is a summary of information provided by the licensee via phone and email:

On October 21, 2025, at 0610 CDT, while reloading fuel to the reactor vessel, an electrical perturbation initiated a control room ventilation isolation signal (CRVIS). The control room air conditioning system (CRACS) 'A' train A/C unit did not start upon the CRVIS due to a blown fuse. The 'B' CRACS A/C unit was out of service for planned maintenance at the time. At 1020 CDT, the 'A' train CRACS A/C unit was returned to service. Both trains of the control room emergency ventilation system (CREVS) were inoperable for 10 minutes. Due to both trains of CRACS and CREVS being inoperable, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v).

This condition caused entry into technical specification (TS) limiting condition for operation (LCO) 3.7.10 condition `E' and 3.7.11 condition `D'. Upon discovery of the condition, fuel movement and core alterations were suspended in accordance with the TS LCO required actions.

There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector was notified.

TRANSPORT OF CONTAMINATED PERSON OFFSITE

The following information was provided by the licensee via phone and email:

"On 10/21/2025 at 0930 EDT an individual fell into the reactor cavity. The reactor cavity is full of water. They ingested some amount of cavity water. The individual was decontaminated by radiation protection personnel but had 300 counts per minute detected in their hair. At 1632 EDT they were sent off site to seek medical attention.

"This is an eight-hour notification, non-emergency, for the transportation of a contaminated person offsite. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xii).

"The NRC Resident Inspector has been notified."

AUTOMATIC REACTOR TRIP

The following information was provided by the licensee via email and phone:

"On October 21, 2025, at 2108 EDT, Unit 1 automatically tripped from 74 percent power due to a negative rate trip. The unit has been stabilized in mode 3 at normal operating temperature and pressure. The reactor trip was uncomplicated, and all control rods fully inserted into the core. This reactor protection system actuation is reportable per 10 CFR 50.72(b)(2)(iv)(B). The auxiliary feedwater pumps actuated as designed because of the reactor trip and is reportable per 10 CFR 50.72(b)(3)(iv)(A) for a valid engineered safety feature (ESF) actuation. Decay heat is being removed via the steam generator power-operated relief valves and Unit 1 is in a normal shutdown electrical lineup. Unit 2 was not affected by this event."

The NRC Resident Inspector has been notified.

AGREEMENT STATE REPORT - LEAKING SOURCE

The following information was provided by the Georgia Radioactive Material Program (the Department) via email:

"On October 8, 2025, a leaking source was discovered while performing a routine leak test. The leak test revealed more than 0.005 mCi of removable contamination of Cs-137. The definitive cause of the leakage was not determined; however, cracks in the source were noticed through visible inspection. The leaking source was placed in a lead pig. The pig and cleanup waste were placed in a double bagged plastic bag and stored behind lead bricks. Removable contamination surveys were performed at the site of the leaking source and on the hands of the physicists. All areas and personnel were found to be free of removable contamination. The licensee will contact a company for waste disposal and will notify the department when the disposal is completed. The incident was reported to our office on October 10, 2025."

GA Incident Number: 109

AGREEMENT STATE REPORT - STOLEN GAUGE

The following information was provided by the Nevada Radiation Control Program via phone and email:

"The radiation safety officer for Universal Engineering Services, [license number] 00-11-14033-01, reported to the Nevada Radiation Control Program that a portable gauge had been stolen from the back of a pick-up truck (all chains were cut) at a hotel where an employee was staying in Reno, this morning at 0815 PDT. The gauge in question is a Troxler, model 3430, serial number 37385, with americium-241/beryllium neutron sealed source with an activity of 40 mCi, and a cesium-137 sealed source with an activity of 8 mCi. The licensee is filing a report to the Reno Police Department for the stolen gauge and has been reaching out to local pawn shops.

"Notification is made under 10 CFR 20.2201(a)(1)(i)."

THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

AGREEMENT STATE REPORT - UNPLANNED CONTAMINATION

The following information was provided by the Illinois Emergency Management Agency and Office of Homeland Security (the Agency) via phone and email:

"The Agency was contacted on 10/15/25 by the radiation safety officer for Elmhurst Hospital (IL-01612-01) to advise of a contamination incident. Reportedly, a vial containing 200 millicuries of Lu-177 was dropped in the facility's hot lab and contaminated a technician. Decontamination efforts are ongoing. Inspectors are headed to the facility to gather additional details and determine the likelihood of exposures exceeding regulatory limits.

"Based on the information currently available. this matter is a reportable unplanned contamination event under 32 Illinois Administrative Code 340.1220(c)(1). It is reportable within 24 hours, which the licensee met.

"Additional updates will be provided as they become available."

Illinois Reference Number: IL250044

OFFSITE NOTIFICATION

The following information was provided by the licensee via phone and email:

"On October 22, 2025, at 0452 EDT, chemistry determined that a report to the State of Michigan, Department of Environment, Great Lakes, and Energy, would be required based on exceeding the National Pollutant Discharge Elimination System permit limit for hydrazine. This exceedance did not exceed any NRC regulations or reporting criteria. This notification is being made solely as a four-hour, non-emergency notification for a notification to another government agency. This event is a 4-hour non-emergency report in accordance with 10 CFR 50.72(b)(2)(xi). There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector will be notified."

MANUAL REACTOR SCRAM

The following information was provided by the licensee via phone and email:

"At 1535 CDT on 10/22/2025, with Unit 1 in mode 1 at 86 percent power, the reactor was manually tripped due to low turbine electro-hydraulic control (EHC) oil system reservoir level, caused by a leak developing in the heater bay. The trip was not complex, with all systems responding normally post-trip. 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).

"Operations responded using the emergency operating procedure for reactor pressure vessel control and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves, which have a separate EHC oil system.

"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."