Event Notification Report for July 18, 2025

EN Revision Imported Date: 7/18/2025

EN Revision Text: LOSS OF SEISMIC MONITORING FOR EMERGENCY PLAN ASSESSMENT

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

"At 1922 CDT on 07/02/2025, the Farley Unit 1 and Unit 2 seismic monitoring panel experienced a fault, rendering the panel nonfunctional.

"Compensatory measures for seismic event classification have been implemented in accordance with Farley procedures.

"This report is being submitted as an eight-hour, non-emergency notification for a loss of emergency assessment capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the seismic monitoring panel is the method for evaluating if an operational basis earthquake (OBE) threshold has been exceeded following a seismic event. This is in accordance with the initiating condition for a seismic event greater than OBE levels and emergency action level HU2. There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

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

The licensee confirmed alternative means of recognizing a seismic event for emergency plan entry are available.

* * * UPDATE ON 07/17/2025 AT 1420 EDT FROM DANIEL HERSHMAN TO JOSUE RAMIREZ * * *

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

"It was determined through event investigation that two additional unplanned events occurred within a 3-year period. The seismic computer experienced an unplanned event on 9/29/24 at 1306 CDT and was restored on 9/30/24 at 1742. The other unplanned event occurred on 3/19/25 at 1120 and was restored to service on 3/24/25 at 1626.
"The NRC Resident Inspector has been notified."

Notified R2DO (Davis)

AGREEMENT STATE REPORT - STUCK OPEN GAUGE SHUTTER

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

"On July 10, 2025, the Department was notified by the licensee that the shutter on a Vega model SH-F1 gauge containing a 1,000 millicurie (original activity) Cs-137 source had failed in the open position during testing. Open is the normal operating position. The licensee reported there is no risk of additional radiation exposure to members of the general public or radiation workers due to this shutter failure. Additional information will be provided as it is received in accordance with SA-300."

Texas incident number: 10209

UNANALYZED CONDITION

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

"The facility is in a safe and stable configuration and no accident has occurred.

"Urenco USA stores '1S' bottles in storage cabinets that are verified as safe-by-design, and have been analyzed for storage in the storage area as sub-critical under all normal and credible abnormal conditions. '1S' bottles were removed from cabinets and placed onto carts awaiting transfer to new approved cabinets in the cylinder receipt and dispatch building (CRDB).

"An analysis exists for this configuration of '1S' bottles on carts in other areas of the plant but does not presently exist for '1S' bottles stored on carts in the CRDB. The collection of '1S' sample bottles on several mobile carts potentially falls outside of the normal operating conditions analyzed in nuclear criticality safety and integrated safety analysis (ISA) related documentation and results in the facility being in a state that was different than analyzed in the ISA.

"Corrective actions have begun."

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

Personnel access to the area has been restricted pending completion of the evaluation.

The licensee has notified NRC Region 2.

AUTOMATIC REACTOR TRIP

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

"At 0959 CDT on 7/16/2025, with Unit 1 in mode 1 at 100 percent power, the reactor tripped coincident with operation of a bus 11 knife switch during performance of [surveillance procedure] SP 1857, 4KV bus 11/12 undervoltage and underfrequency relay test. The trip was not complicated with all systems responding normally post trip.

"Operators responded and stabilized the plant. Decay heat is being removed by discharging steam using the steam dump system and the main feedwater system. Unit 2 is not affected.

"Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72 (b)(2)(iv)(B). The expected actuation of the auxiliary feed water system (an engineered safety feature) is being reported as an eight-hour report under 10 CFR 50.72 (b)(3)(iv)(A).

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

OFFSITE NOTIFICATION

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

"At 1100 EDT on 07/17/2025, North Anna Power Station reported elevated levels of tritium in a ground water monitoring well to the State of Virginia as a non-voluntary reporting of tritium. An investigation is currently ongoing to identify the cause of the elevated tritium levels. The tritium levels in this location do not exceed any NRC regulations or reporting criteria.

"This notification is being made solely as a four-hour, non-emergency notification for a notification of the other government agency. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi). There is no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."