Event Notification Report for September 11, 2025

EN Revision Imported Date: 9/10/2025

EN Revision Text: AGREEMENT STATE REPORT - STUCK OPEN GAUGE SHUTTER

The following information was provided by the SC Department of Environmental Services (the Department) via email:

"The licensee informed the Department via telephone on August 12, 2025, that a fixed gauging device was disabled or failed to function as designed. The licensee reported that the brass shaft that operates the shutter of a fixed gauging device broke in the open position. The device is located on a process vessel. The licensee reported that a representative from a licensed service provider is on-site and is in the process of shielding the device so that it can be removed from service and placed in storage.

"The device is a 5 millicurie cesium-137 Berthold Systems, LLC model 7440.

"The licensee did not report any overexposures or ongoing health/safety concerns.

"This event is still under investigation by the Department."

* * * UPDATE ON 09/10/25 AT 0830 EDT FROM JACOB PRICE TO ERIC SIMPSON * * *

The following information was provided by the SC Department of Environmental Services (the Department) via email:

"On August 13, 2025, the Department conducted an on-site investigation. The details of the event were consistent with the licensee's initial notification and subsequent written report. The Department performed ambient dose rate and removable contamination surveys, which revealed no abnormal readings or contamination. The licensee has contacted vendors and consultants to replace the affected device.

"On September 8, 2025, the Department received the 30-day written report. The details of this report were consistent with the information obtained during the on-site visit and interviews.

"This event remains under investigation by the Department."

EN Revision Imported Date: 9/11/2025

EN Revision Text: AGREEMENT STATE REPORT - DAMAGED MOISTURE DENSITY GAUGE

The following information was provided by the Washington State Department of Health, Office of Radiation Protection (WADOH) via email:

"At 0100 PDT [on 08/14/2025] an intoxicated driver collided with several pieces of equipment in a roadside construction zone, including a nuclear portable gauge. This event occurred on SR 16 eastbound directly before the Tacoma Narrows Bridge in Gig Harbor, Washington. The nuclear gauge that was damaged was a licensed Troxler model 3450. The damage appeared to consist of the handle being separated from the body of the gauge. The gauge was not in use at the time.

"The radiation safety officer (RSO) cordoned off the area and prevented individuals from coming within 150 feet of the source. The timeline of this event is still being investigated. The RSO contacted WADOH at 0205 PDT. Emergency response, consisting of fire and hazmat personnel, arrived on site at approximately 0500 equipped with a Geiger Mueller radiation detection instrument. Two individuals donned Tyvek [suits] and proceeded towards the source, with WADOH directing their response via telephone communication. The highest radiation levels were 15 mR/hr, measured approximately one foot from the source, which indicated that the sources were likely still within the shielded position. The two emergency responders used a shovel to pick the source handle and gauge body up and place the pieces back into the Troxler type 'A' shipping container. This took approximately 8 minutes and the dose received is assumed to be less than 2 mrem each. The container was then closed, and additional radiation surveys were taken. The on contact dose on the exterior of the container was 2 mR/hr, which is below the expected dose rate while within the container. WADOH arrived on-site at approximately 0730 PDT and took contamination surveys on the source assembly, which was visibly intact. No contamination was detected.

"Under Troxler's guidance, the licensee transported the material within the type 'A' container back to their calibration facility to perform leak tests. Leak tests have been performed and are being sent out for counting prior to shipment back to Troxler. The gauge will remain in a secured position until it is shipped back to Troxler. The licensee will follow Troxler guidance and all applicable DOT regulations. A full report will be delivered to WADOH within 30 days. WADOH will continue conversations with the licensee to determine the full scope of the situation, and additional details will be provided as they are found."

Gauge sources: 9 mCi Cs-137, 44 mCi Am-241/Be, and 66 microcuries Cf-252

WA Incident Number: WA 25-009


* * * UPDATE ON 09/10/2025 AT 1759 EDT FROM DANE BLAKINGER TO JOSUE RAMIREZ * * *

The following information was provided by the Washington State Department of Health, Office of Radiation Protection (WADOH) via email:

"Dose assessment: Four responders were on-site. Two responders were in a radiation field of up to 15 mR/hr for 8 minutes. The conservative estimate is a 2 mrem total effective dose equivalent each. Dose to WADOH responder was less than 1 mrem.
"[As part of corrective actions,] WADOH has generated job aids for responding to portable gauge emergencies. Additional procedural changes are being developed. Focused training on similar emergencies is being developed to ensure office-wide readiness.
"The licensee will internally audit all emergency procedures for portable gauge license, including updating the gauge transportation forms with radiation safety officer personal phone number. All required traffic control was in place.
"No further actions required. Corrective actions will be verified during a routine inspection."

Notified R4DO (Deese) and NMSS Event Notification (email)

AGREEMENT STATE REPORT - STUCK SHUTTER

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

"On September 3, 2024, the Agency received notification from the licensee regarding a gauge with a stuck shutter. The gauge, a Ronan model SA1-F37, containing a 40 millicurie cesium-137 sealed source, is reportedly stuck in the open position. Open is the normal operating position. The licensee discovered the gauge failure during a routine planned maintenance exercise. According to the licensee, there is no risk of exposure to workers and members of the public. The licensee has contacted the manufacturer to repair the gauge.

"Additional information will be provided in accordance with SA 300 reporting requirements."


Texas Incident #: 10221
Texas NMED # TX250040

AGREEMENT STATE REPORT - DAMAGED MOISTURE DENSITY GAUGE

The following information was provided by the Louisiana Radiation Protection Division (LDEQ) via email:

"On September 3, 2025, at approximately 1605 CDT, the radiation safety officer (RSO) for the licensee, Raba Kistner, Inc., notified LDEQ concerning an incident in which a Troxler model 3430 soil moisture density gauge, S/N 28457, was rolled over by a bulldozer. The incident occurred at the University of Louisiana at Lafayette New Iberia Research Center at approximately 1515 CDT. The RSO reported that during a direct transmission density measurement, in which the source was submerged in approximately eight inches of soil, the gauge was run over by the bulldozer. The gauge source rod was tilted in the soil approximately 45 degrees from the normal. It could not be determined if the source rod was bent, and no attempt was made to retract the density source into the safe position. The gauge possessed two sealed sources, an 8 mCi Cs-137 source, S/N 750-2469, and a 40 mCi Am/Be-241 source, S/N 47-25460. Both sources are approximately 28 years old. The gauge operator is currently maintaining an exclusion area of approximately 30 feet in radius about the gauge, which had a housing that was partially broken apart during the rollover. No radiation surveys have yet been performed of the gauge or surrounding area. The gauge manufacturer was contacted at time of reporting. The RSO will notify the LDEQ of incident status changes."

Event report ID number: LA20250006

AGREEMENT STATE REPORT - MEDICAL EVENT

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

"On September 3, 2025, the Department received notification from the licensee about a medical event involving a high dose rate treatment that occurred on August 25, 2025. The event was discovered on September 2, 2025, when the patient returned for a subsequent [fractional treatment]."

"A written directive was created to deliver 4,000 cGy over 8 fractions to a scalp lesion with a 30 mm Valencia skin applicator. [A patient treatment simulation was conducted] on August 20, 2025, where the radiation therapist constructed a brain mask for immobilization that included an opening at the top of the head. This was done to allow placement of the skin applicator. On August 25, 2025, the authorized user identified a lesion that was superior to the lesion he had intended to treat, which was not biopsied. The wrong site was treated with 500 cGy by a 7.54 Ci Ir-192 source. The Department has requested additional information and continues to investigate the event."

AZ Incident Number: 25-016

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 - LOST MOISTURE DENSITY GAUGE

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

"The Department received notification from the licensee that a portable gauge was lost/stolen. A technician last saw the gauge on August 28, 2025, at 0130 MST at the technician's residence in Fountain Hills, Arizona. On September 3, 2025, the technician arrived at a jobsite at 1040 MST and realized that the gauge was not in the back of his truck. The gauge is a Troxler model 3411, S/N 17318, containing approximately 8 millicuries of cesium-137 and 40 millicuries of americium-241/beryllium. The Department has requested additional information and continues to investigate the event. The licensee has reported the gauge stolen with the city of Fountain Hills."

Arizona Incident Number: 25-017

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 - STUCK SHUTTER

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

"On September 4, 2025, the Department was notified by the licensee that the shutter on a Texas Nuclear model 5201 fixed source housing had failed in the open position during routine testing. This is the normal operating position for the shutter. The gauge contains a 100 millicurie (original activity) cesium 137 source. The licensee reported that there is no risk of additional radiation exposure to members of the general public or radiation workers. Additional information will be provided as it is received in accordance with SA-300."

Texas NMED # TX250041
Texas Incident #: 10222

AGREEMENT STATE REPORT - LOST EXIT SIGN

The following information is a summary of the report provided by the Maine Radiation Control Program (Maine RCP) via email:

At 0856 EDT, on September 4, 2025, the radiation safety officer (RSO) for the University of Maine Orono contacted the Maine RCP and reported that a tritium exit sign located underneath the UMaine Orono stadium bleachers was discovered to be missing. The current activity would be approximately 17.5 Ci due to decay.

The RSO contacted the members of the University of Maine Facilities Maintenance department, as well as contractors working on site, and it was relayed that heavy construction had been occurring in the facility during the last two months, and that the sign may have been damaged during cleaning. It was surmised that the sign was likely disposed of in the trash, but this could not be directly confirmed by anyone. The RSO will continue to gather additional information that will be included in a written report to be submitted within 30 days.

NMED event notification - ME 2025-005
Model: SRB Technologies Betalux-E/BX
Serial Number: C196983
Source: 21.6 Ci H3

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 - STOLEN GAUGE

The following information was provided by the California Department of Public Health, Radiologic Health Branch (the Department) via email:

"On September 4, 2025, at 0930 PDT, the radiation safety officer (RSO) notified the Radiologic Health Branch that a CPN moisture density gauge had been stolen from a locked trailer at their construction jobsite. The construction manager noticed the company's trailer was unsecured and notified NMG Geotechnical. The gauge was secured within an internal locked cabinet inside the trailer, inside its locked transportation case that has the company name and contact number affixed. The gauge's trigger lock was confirmed to be engaged.

"The City of Carlsbad Police Department was notified, and a theft report was recorded. Maurer Technical Services was also notified. NMG Geotechnical will post a reward for information leading to the return of the stolen equipment. The Department will continue to investigate this event. "

CA incident #: 5010-090425
Model: CPN MC-DRP
Serial Number: Unknown
Source: 10 mCi Cs-137, 50 mCi Am-241/Be

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 - LOST GAUGE

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

"On September 4, 2025, the licensee reported that one of its technicians lost a Troxler 3440 moisture/density gauge. The gauge contains a 40 millicurie Am-241 source and a 10 millicurie Cs-137 source. The radiation safety officer (RSO) stated the gauge was being used at a field site.

"The technician needed to go to the bathroom and placed the gauge into its transport case. The technician locked the transport case, placed it into the back of the truck, and put a locking cable through one of the transport case handles. The technician left the area and, when he arrived at the convenience store, he found the tail gate down and the case and gauge missing. The cable that was through the handle was still secured to the truck and through the case handle, but the handle had been pulled off the case. The technician contacted the RSO and informed him that the gauge was missing.

"The RSO stated the technician and a manager had looked for the gauge. They handed out cards with their contact information to the workers at the job site and contacted local law enforcement. The licensee does not believe any individual would receive any significant exposure due to this event.

"Additional information will be provided as it is received in accordance with SA-300."

TX incident #: 10224
TX NMED # TX250042

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

ENCLOSURE BUILDING BOUNDARY INOPERABLE

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

"Entry into shutdown technical specification action statement due to an identified breach in ventilation ductwork.

"At 2250 EDT on September 9, 2025, it was discovered that there was degraded manway sealant on the manway to fire damper HV-298A. This degraded sealant results in a direct path from the enclosure building to the atmosphere, challenging the enclosure building boundary. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(C).

"There is no impact on the health and safety of the public or plant personnel.

"The plant is currently in a 24-hour technical specification action statement (3.6.5.2) for Unit 2. Unit 3 is not impacted and continues to operate at 100 percent power."

The Resident Inspector has been notified.

UNUSUAL EVENT - RCS IDENTIFIED LEAKAGE GREATER THAN 25 GPM FOR GREATER THAN 15 MINUTES

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

At 1207 EDT on September 10, 2025, Oconee Nuclear Station Unit 1 declared an Unusual Event (SU5.1) due to identified reactor coolant system (RCS) leakage from Unit 1 for greater than 15 minutes. The calculated leak rate was 26 gallons per minute (gpm).
The leakage was identified to be from letdown filter 1A, which was subsequently isolated.
Units 2 and 3 remain at 100 percent power and are unaffected by this event.
This event was terminated at 1353 after isolating the source of the leak.

The NRC Resident Inspector has been notified.

Notified DHS SWO, FEMA Operations Center, CISA Central Watch Officer, FEMA NWC, DHS Nuclear SSA (email), CWMD Watch Desk (email).

OFFSITE NOTIFICATION

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

"At 1207 EDT on September 10, 2025, Oconee Nuclear Station Unit 1 declared an unusual event (Event number 57914). A small reactor coolant system (RCS) leak occurred during routine RCS letdown filter maintenance. The letdown filters were bypassed, and the leak was isolated. The unusual event was terminated at 1353 EDT.
"This notification is being made solely as a four-hour, non-emergency notification for a news release. This event is reportable 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 has been notified."