Event Notification Report for October 09, 2025

AGREEMENT STATE REPORT - STUCK OPEN GAUGE SHUTTER

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

"On October 10, 2025, the Agency received a notification from the licensee regarding a failure of the shutter mechanism on a fixed nuclear gauge. The gauge, a Ronan model SA1, contains a 10 millicurie cesium-137 sealed source. The licensee made the discovery on October 9, 2025. The shutter is stuck in the open position, which is the normal operating position. The licensee stated that there is no risk of additional radiation exposure to members of the public or radiation workers due to this mechanism failure. The licensee has notified a licensed service provider to repair the unit.

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

TX Incident Number: 10238
TX NMED Number: TX250055

AGREEMENT STATE REPORT - GAUGE SHUTTER FAILURE

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

"On October 10, 2025, the Agency received a notification from the licensee regarding a failure of the shutter mechanism on a level measurement gauge. The gauge is a Vega Americas SHRM-B model, containing a 300 millicurie cesium-137 sealed source. The licensee stated that the roll pin, which attaches the shutter handle to the shutter shaft, had detached, resulting in the separation of the handle from the shaft. The shutter shaft connects the handle to the shutter allowing it to be opened or closed. The shutter is currently stuck in the open position, which is the normal operating position. The licensee stated that there is no risk of additional radiation exposure to members of the public or radiation workers due to this mechanism failure. The licensee has notified a licensed service provider to repair the unit. Additional information will be provided in accordance with SA-300 reporting requirements."

Texas Incident #: 10237
Texas NMED #: TX250054

AGREEMENT STATE REPORT - GAUGE SHUTTER FAILURE

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

"The radiation safety officer (RSO) was attempting to lock-out an Ohmart, Cs-137 fixed gauge when they found that the shutter was stuck open. The RSO stated that while trying to close the shutter, they chipped it. At that point, they removed the gauge and attempted to close the shutter in their workshop and were still unsuccessful. The RSO stated that, during continued attempts to close the shutter, they further damaged the shutter. At this point, the RSO fixed a 6-inch steel plate over the beam and put the device in storage. The RSO took surveys and determined the source was adequately shielded. The device will remain in storage, and the gauge manufacturer will be consulted for next steps.

"The RSO reported the event to MDH at approximately 1200 CDT on October 9, 2025."

Manufacturer: Ohmart
Model: unknown at this time
Source: Cs-137
Activity: approximately 80 millicuries

Minnesota Event ID: MN250007

EN Revision Imported Date: 11/3/2025

EN Revision Text: PART 21 - POSITIVE BATTERY POST SEPARATION

The following is a summary of information provided by Paragon Energy Solutions via email:

In May 2025, Quad Cities experienced positive battery post separation from three cells in a safety related battery string at the post seal nut region. Paragon dispatched engineering resources to provide technical assistance to the station during battery string replacement and to perform an initial assessment of the condition. The current postulated cause of the post separation is due to a corrosion mechanism that is still under investigation. In September 2025, Calvert Cliffs reported separation of a positive post from a cell upon initiation of a service test discharge resulting in electrical arcing at the cell post area.

Paragon has not yet identified a defect in the cell post design or manufacturing process which, if corrected, would prevent or mitigate this condition. The affected battery cells have been in service for 14 years and 11 years, respectively. This phenomenon only affects the positive posts on the battery, and the area of the post where corrosion occurs is not visible during routine inspection. Paragon is not stipulating that high cell voltage is the primary indication of the corrosive effect in the positive post, but this indication may allow sites to ensure cells are adequately evaluated for post integrity. Paragon recommends licensees continue normal battery maintenance procedures contained in station instructions.

Affected Plants
Region 1 - Beaver Valley, Calvert Cliffs, Fitzpatrick, Ginna, Millstone, Nine Mile Point, Seabrook
Region 2 - Brunswick, Catawba, McGuire, Robinson, Shearon Harris, Turkey Point
Region 3 - Davis Besse, Dresden, LaSalle, Quad Cities
Region 4 - Callaway, Comanche Peak, Palo Verde, River Bend, South Texas Project

Paragon Contact Information:
Richard Knott
Vice President, Quality Assurance
(518) 450-9706 (C)

*** UPDATE ON 10/31/2025 AT 0711 EDT FROM RICHARD KNOTT TO SAMUEL COLVARD ***

The following information summary was provided by email:

Further analysis is needed and expected to be completed by 12/15/2025. Oconee was added to the list of affected nuclear power plants. Interim advice to licensees was given.

Notified R1DO (Young), R2DO (Mckown), R3DO (Ziolkowski), R4DO (Vossmar), and the Part 21/50.55 Reactors group.

MANUAL REACTOR SCRAM

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

"On October 9, 2025, at 1207 CDT, River Bend Station (RBS) was operating at 100 percent reactor power when a manual reactor protection system (RPS) actuation was inserted as a result of a division-I balance of plant (BOP) isolation. The BOP isolation was a result of a blown fuse during surveillance activity. The BOP isolation resulted in the loss of instrument air system (IAS) and component cooling primary system (CCP) to containment.

"Following the isolation, control room operators entered the applicable abnormal operating procedures (AOP). In accordance with AOP guidance, control room operators inserted a manual reactor scram. All plant systems responded as designed. Immediately after the scram, a reactor water level 3 isolation signal was received as expected.

"Due to the swell from the main turbine trip, a reactor water high level 8 actuation signal was received at 1208 CDT. The level 8 actuation signal was reset at 1211 CDT. At 1237 CDT, control room operators entered the emergency operating procedure (EOP) for high containment pressure. The increase in containment pressure was due to the isolation of the containment vent flow path.

"The isolation signal for IAS and CCP was reset at 1255 CDT. Following the restoration of the isolation signal, control room operators lowered containment pressure and exited the EOP at 1305 CDT.

"Reactor pressure is being maintained by the main turbine bypass valves. Reactor level is being maintained by condensate and main feedwater. RBS is currently in mode 3. No radiological releases have occurred due to this event.

"The event is being reported under 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A) as an event or condition that results in actuation of the RPS when the reactor is critical and as a specified system actuation due to the expected reactor water level 3 isolation signal immediately following the reactor scram, and a subsequent level 8 signal.

"The NRC Resident Inspector has been notified."