Event Notification Report for November 17, 2025

AGREEMENT STATE REPORT - DAMAGED GAUGE

The following is a summary of information provided by the Virginia Radioactive Materials Program (VRMP) via email:

The VRMP was notified by phone of an incident at a soil compaction project site in Wytheville, VA. At approximately 1120 EST, on November 6, 2025, a Troxler 3440 portable nuclear gauge (S/N 71116, 8 mCi Cs-137 and 40 mCi Am-241) was struck by a motor grader while the rod was locked in the safe position within the gauge. The authorized user (AU) was approximately 100 yards from the unattended gauge when the incident occurred. The AU secured the area and contacted their radiation safety officer (RSO) to report the incident. The impact damaged the plastic housing, bent the source rod handle, and broke the depth rod off the device. The licensee and Virginia Department of Transportation (VDOT) RSOs verified the source rod was still locked within the gauge shielding and there was no apparent damage to either source capsules. Surveys indicated the radiation levels were within acceptable ranges. The licensee RSO reported that there were no exposures or injuries. Surveys of the surrounding area and grader tires showed only background radioactivity. The gauge was placed into its transport case and returned to the licensed storage location. A leak test will be performed, and the gauge will be transported to North East Technical Services, Inc., a licensed nuclear gauge service company in Maryland, for further evaluation. VRMP will investigate the licensee.

Virginia event report ID number: VA250005

AGREEMENT STATE REPORT - STUCK OPEN SHUTTER

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

"On November 7, 2025, the Department was notified by the licensee's radiation safety officer that while removing a Berthold model LB7440 gauge for disposal, the shutter was found in the stuck open position. Open is the normal position for the shutter. The gauge contains a 10 millicurie (original activity) cesium-137 source. A shield was attached to the front of the gauge, and it was placed in a shipping drum full of shielding materials. The gauge was transferred to a storage area. The gauge will be shipped for disposal. No individual received any significant exposure due to this event. Additional information will be provided as it is received in accordance with SA-300."

Texas incident number: 10243
Texas NMED number: TX250059

AGREEMENT STATE REPORT - RECOVERED GAUGE

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

"A gauge service provider reported that a member of the public had contacted them after finding an uncontrolled portable nuclear gauge. The individual observed the gauge fall from the back of a truck and called the service provider's number displayed on the gauge transportation case. The member of the public indicated that the transport case appeared to be intact. By the time the member of the public was contacted [by the Department], the licensee had already recovered the gauge. The Department contacted the licensee who confirmed that the gauge involved was a Troxler model 3440, serial number 24768, containing approximately 9 mCi of Cs-137 and 44 mCi of Am-241/Be.

"An investigation is ongoing, and the Department is awaiting additional information from the licensee."

Colorado event report ID number: CO250041

AGREEMENT STATE REPORT - LOST EXIT SIGNS

The following is a summary of information provided by the Colorado Department of Public Health and Environment via email:

The licensee reported two exit signs, each containing 6.0 Ci of tritium, were lost in Commerce City, Colorado.

Manufacturer: Isolite Corporation
Model Number: SLX60

Colorado Event Number: CO250042

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

UNUSUAL EVENT - LOSS OF ALL OFFSITE POWER TO VITAL BUSSES

The following information was provided by the licensee via phone:

On November 14, 2025, at 1351 CST, while in a system outage window, for the reserve auxiliary transformer 'B' bus work inspections, the emergency reserve auxiliary transformer tripped. This resulted in the loss of offsite power to all vital busses.
At 1402 CST, a notice of unusual event was declared (MU.1) due to the loss of all offsite power to vital busses.
All three emergency diesel generators actuated and energized the vital busses.

Notified DHS SWO, DOE Ops Center, FEMA Operations Center, FEMA NWC, CWMD Watch Desk, HHS Ops Center, CISA Central Watch Officer, USDA Ops Center, EPA EOC, FDA EOC (email), DHS Nuclear SSA (email), DHS NRCC THD Desk (email), FEMA NRCC SASC (email), and FERC Reliability Monitoring Center (email).

* * * UPDATE ON 11/16/2025 AT 0647 EST FROM JASON VINCENT TO KERBY SCALES * * *

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

On November 16, 2025, at 0500 CST, the Unusual Event was terminated. All offsite electrical power has been restored, and the plant is in a normal electrical lineup.

The NRC Resident Inspector was notified.

Notified R3RA (Geissner), NRR (Groom), NSIR (Williams), R3DO (Ziolkowski), NRR EO (Mckenna), IR MOC (Grant), R3PAO (Mitlyng), R3DRSS (Heck).

Notified DHS SWO, DOE Ops Center, FEMA Operations Center, FEMA NWC, CWMD Watch Desk, HHS Ops Center, CISA Central Watch Officer, USDA Ops Center, EPA EOC, FDA EOC (email), DHS Nuclear SSA (email), DHS NRCC THD Desk (email), FEMA NRCC SASC (email), and FERC Reliability Monitoring Center (email).

AUTOMATIC ACTUATION OF EMERGENCY DIESEL GENERATORS

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

"At 1351 CST on 11/14/25, with the unit in mode 1 at 99 percent power, an actuation of the division 1, 2, and 3 emergency diesel generators (EDGs) occurred when a fault occurred on the emergency reserve auxiliary transformer (ERAT). The reserve auxiliary transformer `B' was de-energized and isolated for maintenance. The cause of the division 1, 2, and 3 EDGs auto-start was an actuation of the loss of voltage function undervoltage relays for each respective bus. The division 1, 2, and 3 EDGs automatically started as designed when the applicable loss of voltage signals were received.
"This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the division 1, 2, and 3 EDGs.
"The NRC Resident Inspector has been notified."

AUTOMATIC ACTUATION OF EMERGENCY AC POWER SYSTEM

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

"At 2254 EST, on November 14, 2025, with Unit 2 in no mode at zero percent power, an actuation of the emergency AC power system occurred during verification of electrical system alignment. The reason for the Keowee Hydro units actuating was due to loss of power to the Unit 2 main feeder busses when a potential transformer drawer for the Unit 2 main feeder busses was opened, resulting in breakers supplying power to the Unit 2 main feeder busses opening. The Keowee Hydro Units 1 and 2 automatically started as designed when a main feeder bus undervoltage signal was received. There was no impact to Unit 1 or Unit 3.

"This event is being reported in accordance with 10CFR50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the emergency AC power system. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."

CONTROL ROOM EMERGENCY VENTILATION SYSTEM INOPERABLE

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

"At 0911 EST, on 11/17/2025, it was discovered that both trains of the control room emergency ventilation system were simultaneously inoperable due to an unauthorized door breach of a door in the control room envelope; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). At 0913 EST, the door was closed, and both trains of the control room emergency ventilation system were restored to operable.

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