Event Notification Report for September 26, 2025

AGREEMENT STATE REPORT - LOST GAS CHROMATOGRAPHY DEVICES

The following information was provided by the Illinois Emergency Management Agency (the Agency) via email:

"As a result of an ongoing investigation into unresponsive general licensees, the Agency became aware that five (5) generally licensed Perkin-Elmer model n610-0063 gas chromatography devices, each containing 15 millicuries of Ni-63, are missing.

"Reportedly, in late 2024, the licensee went through a transition of layoffs and is currently being bought by another company. Due to the change in employees, the location of these devices is unknown.

"The licensee failed to properly transfer or dispose of the devices (serial numbers 4377, 6055, 6273, 6202, and 7067). The facility manager is currently trying to reach out to past employees for information. The Agency has reached out to the distributor to try and locate the devices.

"The quantity of radioactive material involved, while unlikely to be dangerous to the public, is reportable within 30 days to the Agency and the U.S. NRC. Investigation is ongoing, and any updates will be reported."

Illinois Event Number: IL250040

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 - MEDICAL EVENT

The following information was provided by the Radiation Health Branch of the Kentucky Department for Public Health and Safety (KY RHB) via email:

"KY RHB was notified on 9/18/2025 by the radiation safety officer (RSO) from the University of Louisville Hospital of an issue with five Sir-Sphere Y-90 doses.

"Due to a software issue that had a calculation error converting GBq to mCi, 5 patients were underdosed to a point that their dose was more than 20 percent outside of the prescribed dose, and the dose to the organ (liver) was more than 50 mSv from the prescribed dose.

"The RSO is meeting with the physician today to discuss the issues. The issue with the software has been fixed."

KY Event Number: TBD

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 - MEDICAL EVENT

The following is a summary of information received from the Alabama Office of Radiation Control (the Agency) via email:

On September 3, 2025, an administering physician encountered resistance while delivering a dose of Y-90 Theraspheres. The patient received 67.2 mCi of a prescribed 90.7 mCi (24.4 percent underdose). The delivery apparatus was placed in storage to decay. Once decayed, it will be sent to the manufacturer (Boston Scientific) for evaluation. The patient was informed and advised that the delivered dose is acceptable therapeutically.

The Agency was informed of this incident on September 18, 2025, and will provide additional information as the investigation continues.

Alabama Incident Number: 25-04

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.

NON-POWER REACTOR - UNPLANNED HIGH-POWER TRIP

The following information was summarized from the licensee via phone and email:

On September 24, 2025, at 1511 MDT, a high-power trip occurred (operation of safety channels 2 and 3). The reactor was being operated by a senior reactor operator (SRO) and a student authorized operator. A positive-period excess reactivity measurement was being performed. The reactor power rose to 5.64 watts. The technical specifications power limit of 6 watts plus was not exceeded, and both safety channels functioned to shut the reactor down.

This prompt notification for a high-power trip is in accordance with current procedures and technical specification 6.9.2.a.7. The proximate cause of this event was operator distraction. The reactor room had two visitors at the time of the event, an NRC inspector and a University of New Mexico nuclear engineering instructor. The instructor was engaging the student authorized operator and the SRO on matters relating to a laboratory activity ongoing in another part of the building. The SRO responded to the rising power too slowly to avoid the high-power trip.

AUTOMATIC REACTOR TRIP

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

"On September 24, 2025, at 1347 CDT, Arkansas Nuclear One, Unit 1, (ANO-1) experienced an issue with the X-01B main phase transformer which led to an automatic trip on reactor protection system (RPS).

"ANO-1 is currently stable in mode 3, maintaining pressure and temperature with the P-1A and P-1B main feedwater pumps and steaming to the main condenser. All rods inserted and systems functioned as expected.

"There is no radiological release on either unit as a result of this event.

"This report satisfies the reporting criteria of 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A) for the reactor protection system actuation.

"The NRC Senior Resident Inspector has been notified.

"Unit 2 was not affected."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
ANO-1 retains access to all normal sources of offsite power.

MANUAL REACTOR TRIP

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

"On September 24, 2025, at 1829 CDT, Comanche Peak, Unit 1, was manually tripped due to a trip of both main feed water (MFW) pumps. All auxiliary feedwater pumps started due to the trip of both MFW pumps. This event is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) for a reactor trip and 10 CFR 50.72(b)(3)(iv)(A) for an actuation of auxiliary feedwater. Unit 1 is being maintained in mode 3 in accordance with integrated plant operating procedures. Decay heat is being rejected to the main condenser via the steam dump valves. The cause of both MFW pumps tripping is unknown and under investigation.

"The NRC Resident Inspector was notified."


The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
No evolutions were ongoing at the time of the event.

TWO TRAINS OF ECCS INOPERABLE

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

"On 9/23/2025 at 2214 CDT, the South Texas Project Unit 1 (STP-1) Train B reactor containment fan cooler (RCFC) chilled water supply outside containment isolation valve (OCIV) 1-CC-MOV-0137 was declared inoperable due to a material condition. This rendered Train B component cooling water inoperable which cascaded to Train B emergency core cooling system (ECCS) subsystem to render it inoperable. STP-1 entered Technical Specification (TS) 3.5.2 Action A for Train B ECCS, requiring restoration within 7 days or apply the requirements of the (Configuration Risk Management Program) CRMP.

"On 09/25/2025 at 1229, Train A essential chiller 12A was declared inoperable due to inability to maintain chiller water outlet temperature less than 52 Fahrenheit. This cascaded down to the Train A ECCS Subsystem to render it inoperable. STP-1 entered TS 3.5.2 Action B due to less than two of the required subsystems operable, within 1 hour restore at least two subsystems to operable status or apply the requirements of the CRMP, or be in at least Hot Standby within the next 6 hours and in Hot Shutdown within the following 6 hours.

"On 09/25/2025 at 1329, STP-1 entered CRMP based on two ECCS subsystems remaining inoperable longer than 1 hour. These subsystems are used for accident mitigation. Unit 1 remains in mode 1."

LOST SOURCE

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

"This loss of material report is prepared per 10 CFR 20.2201(a)(1)(ii) for a loss of material of a Ra-223 dichloride (Xofigo) radiopharmaceutical package that was lost on 8/25/2025, by a [common carrier]. The package left the facility of RAM license 34-31473-03MD at 1353 EDT on 8/25/2025, to be sent to a customer location in Lincoln, NE. The package was sent through [the common carrier] in Memphis, TN, where it was declared lost on 9/3/2025. The package contained one vial of Ra-223 dichloride with a total activity at time of shipment of 92.8 microcuries. The shipment was planned to arrive in Lincoln, NE, by 1200 MST on 8/27/2025."

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