Event Notification Report for November 13, 2025

AGREEMENT STATE REPORT - MEDICAL EVENT

The following is a summary of the information provided by the Louisiana Department of Environmental Quality (LA DEQ) via email:

The LA DEQ received notification from the licensee's radiation safety officer (RSO) that a prostate cancer patient, who was prescribed boost therapy by implantation of 83 seeds containing 1.26 mCi of Pd-103 each into the prostate, was found to have received the implantation of all seeds into the perineum instead. This was discovered by the licensee's medical physicist at approximately 1738 CST on November 4, 2025.

The improper seed implantation was detected as a result of the physicist's analysis of the post-computed tomography (CT) scan. The physicist reported the medical event without delay to the RSO. The RSO reported the medical event in accordance with Louisiana Administrative Code (LAC) 33:XV.712.B.2. at approximately 0825 CST on November 5, 2025. The RSO stated the post-CT scan had been performed on October 27, 2025, at Our Lady of the Lake Regional Medical Center (OLOL), Baton Rouge, LA. Only CT technologists had reviewed the scan on that date and the improper placement of the seeds was not detected at that time.

The seed implantation procedure was conducted at OLOL on July 1, 2025. The patient's urologist was present during the implantation procedure. The RSO stated the root cause of the medical event was still under investigation. The two root cause hypotheses are: 1) faulty zeroing of the ultrasound that the oncologist used to guide implantation of seeds into the patient's prostate due to confusion of the balloon and the patients unusually narrow pelvic arch and 2) movement on the part of the patient pushed the balloon partly out, resulting in incorrect seed implantation. No radiation dose to either the patient's bladder or rectum is suspected. The referring physician and patient will be notified of the medical event within the required 24-hour period.

Louisiana report ID number: LA2500012

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

AGREEMENT STATE REPORT - DAMAGED GAUGE

The following information was provided by the Oklahoma Department of Environmental Quality via email:

"The Oklahoma Department of Environmental Quality (DEQ) received a report from Kleinfelder, Inc. that a nuclear gauge [incident] occurred on November 4, 2025, at approximately [1430 CST] at the Atoka Pump Station Vault Pit Excavation Site.

"During site operations, a Kleinfelder vehicle struck a Humboldt nuclear gauge (serial number: 3753) when moving the vehicle to avoid a collision with an on-site excavator. At the time, the gauge was positioned behind the vehicle. The impact caused the source rod to break while in the retracted position.

"Immediate safety protocols were enacted as follows:
"The vehicle was left in place.
"All personnel were evacuated from the area.
"A 15-foot perimeter was established around the source using caution tape.

"Radiation survey meter readings were completed at the four cardinal points surrounding the portable nuclear gauge.
"At the truck perimeter: 0.00 mR/hr
"After the truck was moved (approximately 3 feet from the source): 0.02 mR/hr

"The gauge and broken source rod (in the retracted position) have been safely packed into the transport case and are currently stored [at a location in Oklahoma City].

"In accordance with regulatory requirements, the incident was reported to the Oklahoma DEQ via their Incident Line (1-800-522-0206) at [1753 CST] on November 4, 2025.

"A leak test was conducted on November 5, 2025, and is currently being processed."

AGREEMENT STATE REPORT - MEDICAL EVENT

The following information was provided by the Texas Department of State Health Services (the Department) via email:

"On November 6, 2025, the Department received a report from the licensee's radiation safety officer (RSO) stating that they had discovered three under exposure events had occurred using Y-90 TheraSphere beads. The events were discovered during a review of these procedures conducted by a new manager. The events occurred on September 11, [September] 18, and [September] 22, 2025.

"In the September 11 event, the patient was prescribed to receive 34.3 millicuries (mCi) but only received 20.0 mCi. In the September 18 event, the patient was prescribed two separate procedures of 34.3 and 48.9 mCi, but received 23.6 and 31.8 mCi [respectively]. In the September 22 event, the patient was prescribed 35.7 mCi but received 26.4 mCi. The final dose calculations were based on the recorded radiation readings taken on the delivery devices after the procedures.

"The RSO stated they have reviewed the records for the events and interviewed the individual who had taken the after-procedure radiation readings and was not able to determine the cause of the underexposures. The prescribing physicians in each case have been notified of the error. The patients will be notified by their physician of the events. The RSO stated they are continuing to investigate the cause of the under exposures. The RSO stated they do not expect any adverse effects on the patients. Additional information will be provided as it is received in accordance with SA-300."

Texas Incident #: 10242
Texas NMED # TX250058

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

ACTUATION OF AUXILIARY FEEDWATER SYSTEM

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

"At 0748 CST, on November 12, 2025, Callaway Plant experienced an automatic actuation of the auxiliary feedwater (AFW) system in response to auxiliary feedwater actuation signals (AFAS). A low suction pressure signal was also received which aligned the AFW pumps to essential service water (ESW). An unknown amount of water from the ultimate heat sink (UHS) entered the steam generators, necessitating a plant shutdown due to exceeding secondary water chemistry program action levels. During the shutdown, with the plant at approximately 28 percent power, high vibration was received on the main turbine, requiring a manual turbine trip. The cause of the AFAS is not yet known. The plant is currently stable in mode 3.

"This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A).

"There was no impact on the health and safety of the public or plant personnel. 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 via steam dump valves to the main condenser.

HIGH PRESSURE COOLANT INJECTION INOPERABLE

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

"On November 12, 2025, at approximately 1250 EST, during surveillance testing of the high-pressure coolant injection (HPCI) system the HPCI minimum flow valve (E4150F012) would not open during stroke testing. HPCI had been removed from service for quarterly surveillance testing at 0957, November 12, 2025. The unplanned inoperability condition began at 1250 when a stroke time test was attempted, and the valve did not reposition. Since HPCI is a single-train safety system, this meets the criterion for event notification per 10CFR50.72(b)(3)(v)(D) as a condition that, at the time of discovery, could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident, based on loss of a single train safety system. Reactor core isolation cooling was and has remained operable. The Senior NRC Resident Inspector has been notified. The failure is currently under investigation."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

Limiting conditions for operation 3.5.1 and 3.6.1.3 were entered to address HPCI inoperable. The site remains on normal offsite power, and all emergency diesel generators remain available.