A worker fell into a nuclear reactor pool

U.S. Nuclear Regulatory CommissionOperations Center EVENT REPORTS FOR10/21/2025 – 10/22/2025

EVENT NUMBERS 5799457996579975799057991579925799858002

Facility: Wolf Creek Region: 4 State: KS Unit: [1] [] [] RX Type: [1] W-4-LP NRC Notified By: Michael J. Payne HQ OPS Officer: Josue Ramirez

Emergency Class: Non Emergency 10 CFR Section: 50.72(b)(3)(v)(D) – Accident Mitigation

Emergency Class: Non Emergency 10 CFR Section: 50.72(b)(3)(xii) – Offsite Medical

Emergency Class: Non Emergency 10 CFR Section: 50.72(b)(2)(iv)(B) – RPS Actuation – Critical 50.72(b)(3)(iv)(A) – Valid Specif Sys Actuation

Emergency Class: Non Emergency 10 CFR Section: Agreement State

Person (Organization): Young, Matt (R1DO) NMSS_EVENTS_NOTIFICATION (EMAIL)

Emergency Class: Non Emergency 10 CFR Section: Agreement State

Person (Organization): Ziolkowski, Michael (R3DO) NMSS_EVENTS_NOTIFICATION (EMAIL)

Facility: Palisades Region: 3 State: MI Unit: [1] [] [] RX Type: [1] CE NRC Notified By: Scott Moore HQ OPS Officer: Robert A. Thompson

Emergency Class: Non Emergency 10 CFR Section: 50.72(b)(2)(xi) – Offsite Notification

Emergency Class: Non Emergency 10 CFR Section: 50.72(b)(2)(iv)(B) – RPS Actuation – Critical

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.”

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.”

Notification Date: 10/21/2025 Notification Time: 14:37 [ET] Event Date: 10/21/2025 Event Time: 06:10 [CDT] Last Update Date: 10/21/2025

Person (Organization): Vossmar, Patricia (R4DO)

Facility: Palisades Region: 3 State: MI Unit: [1] [] [] RX Type: [1] CE NRC Notified By: Scott Moore HQ OPS Officer: Josue Ramirez

Notification Date: 10/21/2025 Notification Time: 16:52 [ET] Event Date: 10/21/2025 Event Time: 16:32 [EDT] Last Update Date: 10/21/2025

Person (Organization): Edwards, Rhex (R3DO) Grant, Jeffery (IRMOC) Phil McKenna (NRR EO)

Facility: North Anna Region: 2 State: VA Unit: [1] [] [] RX Type: [1] W-3-LP,[2] W-3-LP,[3] M-4-LP NRC Notified By: Nick Wilson HQ OPS Officer: Josue Ramirez

Notification Date: 10/21/2025 Notification Time: 23:10 [ET] Event Date: 10/21/2025 Event Time: 21:08 [EDT] Last Update Date: 10/21/2025

Person (Organization): Mckown, Louis J (R2DO)

Rep Org: Georgia Radioactive Material Pgm Licensee: Piedmont Heart Institute Region: 1 City: Douglasville State: GA County: License #: GA 1195-2 Agreement: Y Docket: NRC Notified By: Avionne Fortner HQ OPS Officer: Karen Cotton

Notification Date: 10/16/2025 Notification Time: 08:20 [ET] Event Date: 10/08/2025 Event Time: 00:00 [EDT] Last Update Date: 10/16/2025

Rep Org: NV Div of Rad Health Licensee: Universal Engineering Services Region: 4 City: Reno State: NV County: License #: 00-11-14033-01 Agreement: Y Docket: NRC Notified By: Corey Creveling HQ OPS Officer: Ian Howard

Notification Date: 10/16/2025 Notification Time: 13:51 [ET] Event Date: 10/16/2025 Event Time: 08:15 [PDT] Last Update Date: 10/16/2025

Person (Organization): Vossmar, Patricia (R4DO) NMSS_EVENTS_NOTIFICATION (EMAIL) ILTAB, (EMAIL) (EMAIL)

Rep Org: Illinois Emergency Mgmt. Agency Licensee: Elmhurst Hospital Region: 3 City: Elmhurst State: IL County: License #: IL-01612-01 Agreement: Y Docket: NRC Notified By: Kimberly Stice HQ OPS Officer: Ian Howard

Notification Date: 10/16/2025 Notification Time: 16:35 [ET] Event Date: 10/15/2025 Event Time: 00:00 [CDT] Last Update Date: 10/16/2025

Notification Date: 10/22/2025 Notification Time: 08:06 [ET] Event Date: 10/22/2025 Event Time: 04:52 [EDT] Last Update Date: 10/22/2025

Person (Organization): Edwards, Rhex (R3DO)

Facility: Clinton Region: 3 State: IL Unit: [1] [] [] RX Type: [1] GE-6 NRC Notified By: Pat Bulpitt HQ OPS Officer: Josue Ramirez

Notification Date: 10/22/2025 Notification Time: 18:57 [ET] Event Date: 10/22/2025 Event Time: 15:35 [CDT] Last Update Date: 10/22/2025

Person (Organization): Edwards, Rhex (R3DO)

Power Reactor Event Number: 57994 Facility: Wolf Creek Region: 4 State: KS Unit: [1] [] [] RX Type: [1] W-4-LP NRC Notified By: Michael J. Payne HQ OPS Officer: Josue Ramirez Notification Date: 10/21/2025 Notification Time: 14:37 [ET] Event Date: 10/21/2025 Event Time: 06:10 [CDT] Last Update Date: 10/21/2025 Emergency Class: Non Emergency 10 CFR Section: 50.72(b)(3)(v)(D) – Accident Mitigation Person (Organization): Vossmar, Patricia (R4DO)