Event Notification Report for November 06, 2025

EN Revision Imported Date: 11/6/2025

EN Revision Text: LOSS OF SAFETY FUNCTION

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

"On October 12, 2025, Columbia Generating Station (CGS) was performing a reactor building emergency cooling test. At 1428 [PDT], an air damper associated with the division 1 motor control center (MCC) room cooling failed to perform its intended function to close. This MCC supports the operation of one subsystem of the standby gas treatment system (SGT).

"At 1440, a second air damper, associated with the division 2 MCC room cooling, also failed. This MCC supports the operation of the other SGT subsystem. Field operators were dispatched to investigate the potential cause.

"At 1627, the first air damper that had failed was observed to have closed on its own without further operator action. Operators subsequently determined that failure of the air damper to close rendered the associated emergency room coolers inoperable.

"At 1705, [the division 2 MCC] was declared inoperable and technical specification action statement 3.8.7.A was entered. From 1440 to 1627, CGS was in a condition that required both SGT subsystems to be declared inoperable due to the loss of emergency room cooling to their associated MCCs. This condition constitutes a loss of safety function of SGT and secondary containment. It could have challenged the station's ability to control a radioactive release had one occurred during that time.

"This notification is being made pursuant to 10 CFR 50.72(b)(3)(v)(C) and (D) due to the loss of safety function of both trains of SGT and secondary containment for approximately 2 hours."

The Resident Inspector was notified.

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

At the time of notification, the licensee had exited all technical specification action statements.

* * * RETRACTION ON 11/5/2025 AT 1925 EST FROM JERRY AINSWORTH TO ERNEST WEST * * *

"On October 12, 2025, at 2152 PDT, Columbia Generating Station notified the NRC pursuant to 10 CFR 50. 72(b)(3)(v)(C) and (D) due to the loss of safety function of both trains of standby gas treatment (SGT) and secondary containment for approximately 2 hours under Event Notification 57982.

"The notification was made due to the failure of two dampers to close during testing of the Reactor Building Emergency Cooling System. The dampers that failed to close were cross-divisional and affected rooms with equipment necessary for both trains of the SGT system which supports the safety function of secondary containment.

"Following the event, engineering conducted an evaluation to determine if both air dampers remaining open during a loss of cooling accident would have put any safety-related equipment at risk due to potential changes in radiological and environmental conditions within the associated motor control center (MCC) rooms.

"The engineering evaluation determined temperatures and humidities would not have exceeded limits in the MCC rooms due to the dampers being left open. Additionally, any increase in radiation would be considered negligible and would not affect the ability of the equipment to perform their design functions. Therefore, the safety-related equipment within the MCC rooms would have been available and operable to perform their design function were an accident to occur. Consequently, the failure of two dampers to close during testing is not considered to be an event or condition that could have prevented fulfillment of the safety function of SGT and secondary containment and did not impact the ability to mitigate the consequences of an accident or control the release of radioactive material, therefore, event notification 57982 is retracted.

"The Resident Inspector has been notified."


Notified R4DO (Vossmar)

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 October 29, 2025, a radiation safety officer (RSO) for Tetra Tech BAS, Inc. contacted the Department about a moisture density gauge that was stolen from a temporary storage unit. The gauge was a CPN Model MC-3, S/N M39068922 (10 mCi nominal of Cs-137 and 50 mCi nominal of Am:Be-241). The gauge was stored in a Conex box located at a construction site in San Juan Capistrano, California.

"The construction site is secured with fencing and a locked gate. The gauge was last used by Tetra Tech on October 28, 2025. The gauge case was locked with two padlocks, secured with a chain and two pad locks inside the locked Conex box. When the operator arrived at the site the following morning, the gate was open with the lock cut. The operator then discovered the lock on the Conex box was cut and the door open. An inspection of the inside of the Conex box found that the gauge box and miscellaneous equipment were taken from the Conex box. The operator then contacted the RSO and filed a report with the Orange County Sheriff's Department. The licensee is still investigating the incident. The Department will continue to investigate the incident."

CA incident number: 5010-102925

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 SOURCE

The following information was provided by the Utah Division of Radiation Control via email:

"An industrial radiography source failed to return to the shielded position. While setting up for a shot, the radiographers repositioned the drive cable to improve their view. The cable was inadvertently placed on a hot pipe, melting approximately 5 feet of the 35-foot drive cable near the connection point. As a result, the source could not be retracted into the shielded position. The radiographer notified the radiation safety officer. A source retrieval team was dispatched to the site. The team removed the drive handle and manually pulled the source back into the camera, securing it in the fully shielded position. One licensee personnel, trained in source retrieval, received the most dose during the incident at 28 mR during the retrieval operation according to his Mirion Instandose dosimeter and corroborated by his worn personal electronic dosimeter."

Device: 880 Delta
Activity: 49.4 Ci of Ir-192

Utah Report Number: UT250003

AGREEMENT STATE REPORT - STUCK SOURCE

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

"On October 29, 2025, the Agency received a notification from the licensee regarding a source disconnect that occurred during an industrial radiography operation at a temporary job site. The radiography camera involved is a QSA Global Delta 880 model, containing a 102 curie iridium-192 sealed source (original activity date October 16, 2025). The licensee stated that on October 28, 2025, the guide tube through which the radioactive source travels became crimped, resulting in the source becoming stuck in the exposed position and preventing normal retraction into the shielded position. The licensee stated that a technician crimped the source tube by placing it through a swivel mechanism equipped with pressure clamps, rather than using a separate rod and properly attaching the source tube to the rod. The clamping pressure deformed the guide tube, causing the drive cable to fail when excessive force was applied by the technician to retract the source. The technician contacted one of the licensee's authorized source recovery experts who responded to the site. The licensee stated that the source was safely recovered and returned to the locked, shielded position using an empty camera for transfer. The source is currently stored at the licensee's workshop. The licensee stated that dosimetry badges for all workers present at the time of the incident have been sent out for processing to the service provider. The licensee stated that there was no exposure to members of the public as a result of this event.

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

Texas Incident #: 10240
Texas NMED # TX250057

AUTOMATIC EMERGENCY DIESEL GENERATOR ACTUATION

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

"At 1003 Central Standard Time (CST), with [Unit 1] in mode 5 at 0 percent power, an actuation of the 'A' emergency diesel generator (EDG) occurred when energizing main transformers from the switchyard for post-installation soak. The energization was coordinated with transmission system operators using approved procedures, however, grid conditions external to the substation allowed the voltage to drop below the NB01 undervoltage relay setpoint. The EDG automatically started as designed and picked up the loads on the NB01 bus. All safety systems responded as designed. Substation parameters immediately recovered to normal values, and all systems were restored to [normal] standby conditions.

"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 'A' EDG. There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

OFFSITE NOTIFICATION

The following information was provided by San Onofre Nuclear Generating Station (SONGS) via phone and email:

"At 1109 PST, SONGS made [an] official notification to the [California] Department of Toxic Substance Control (DTSC) relating to one violation/citation non-minor, requiring corrective action related to the hazardous waste facility, permit CAD000630921.

"Specifically, SONGS violated 22 California Code of Regulations (CCR) 66270.30(a) and California Health and Safety Code 25202(a), in that SONGS failed to comply with the conditions of the permit, specifically Part V `Special Conditions,' #5. To wit, DTSC inspectors observed the secondary containment which failed to be free of cracks or gaps in a waste management unit located in the [Hazardous Materials] Area - South Yard Facility (SYF), Section A.

"During the physical inspection, the inspector noted holes were drilled into the slab (the containment system) of mixed waste/hazmat storage pad areas.

"Because the identified holes only partially penetrate the secondary containment (i.e., the concrete pad), the secondary containment remains functional and intact and is sufficiently impervious to contain leaks, spills and accumulated precipitation.

"SONGS is in discussions with DTSC to determine if the holes partially penetrating the pad exceed the permit requirement."

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

SONGS will notify NRC Region IV of this event.