Event Notification Report for April 09, 2025

CONCURRENT REPORT - OFFSITE NOTIFICATION DUE TO NON-RADIOLOGICAL MEDICAL TRANSPORT

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

"At approximately 0015 EDT on April 1, 2025, while exiting from an adjacent work area, an electrician was sprayed with ammoniated water from a leaking hose on a chiller unit. The employee proceeded to a nearby safety shower and rinsed for twenty minutes. Columbia Fuel Fabrication Facility (CFFF) emergency brigade medical first responders provided initial medical treatment. Subsequently, the employee was transported by ambulance to an offsite medical facility and was admitted for further evaluation.

"The emergency brigade performed cleanup of the ammoniated water leak and engineering calculations confirmed that the leak contained less than a reportable quantity of ammonia. A courtesy notification was made to the South Carolina Department of Environmental Services in accordance with established communications protocols.

"The event did not involve special nuclear material or radioactive contamination. The issue has been entered into the corrective action program and the chiller unit will remain down pending further investigation. The CA-134 restart process, [a corrective action protocol], will be followed to ensure appropriate event investigation and recovery actions.

"This concurrent report is being made in accordance 10 CFR 70 Appendix A(c) because a 24-hour report was made to the South Carolina Department of Labor (SCDOL) per 29 CFR 1904.39(a)(2). SCDOL was notified of the incident and in-patient hospitalization of the employee at 1518 EDT on April 1, 2025."

AGREEMENT STATE REPORT - STUCK OPEN GAUGE SHUTTER

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

"At 1725 CDT on 4/1/2025, Suzano Packaging notified the Department by email that the rotor pin for the shutter in one of their process gauges on digester #8 was sheared. The discovery was made while attempting to lock out the gauge for process maintenance.

"The affected gauge is as follows:

"OHMART-03240310036 SR2, SN-4731C0, Cs-137, 1000 microcuries.

"Licensee actions are as follows:

"A technical representative from BBP Sales [LLC, a dealer and servicer of OHMART Vega Corporation Scientific Instruments] determined on 4/1/2025 that the gauge cannot be repaired in place and steps have been implemented to acquire a replacement gauge.

"The process continues to run safely, with no additional exposure to workers, but with confined space entry being prohibited.

"Digester #8 remains in service with the affected gauge performing measurements as required.

"Upon receipt of the replacement gauge, maintenance will be scheduled with BBP Sales technical support to safely remove the affected process gauge from service and replace it with the new unit.

"The investigation is ongoing, and reporting will proceed in accordance with SA-300."

Arkansas Event Number: AR-2025-001

AUXILIARY FEEDWATER SYSTEM INOPERABLE

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

"On April 7, 2025, at 2000 EDT, it was discovered that all pumps in the auxiliary feedwater system were inoperable due to the loss of control power to the `B' train emergency feedwater (EFW) flow control valve which supplies the `D' Steam Generator. The redundant `A' Train EFW flow control valve for the `D' Steam Generator remains functional, as well as the capability of the auxiliary feedwater system to supply all steam generators.

"The `A' and `B' EFW flow control valves are arranged in a series configuration for each steam generator. Failure of any of the 8 EFW flow control valves to meet its surveillance requirements will render all EFW pumps inoperable per technical specifications (TS).

"This condition is being reported pursuant to 10 CFR 50.72(b)(3)(v)(B).

"The NRC Resident Inspector has been notified."

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

Troubleshooting is ongoing for the cause of the loss of control power. The licensee is currently in TS limiting condition for operation 3.7.1.2 action statement 'D' to restore at least one auxiliary feedwater pump to operable status as soon possible.

PART 21 - GENERAL ELECTRIC TIME DELAY RELAY FAILURE

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

This is a report made in accordance with 10 CFR Part 21.21 on a failure of a Curtiss Wright (CW) supplied General Electric (GE) time delay relay.

On 12/10/24, Constellation notified CW about the failure of the relay. Constellation stated the relay failed a planned maintenance test. The induction disc was unable to complete the full travel towards the under-voltage trip due to obstruction from the stationary contact, which slipped down along the shaft upon which it was mounted, and made contact with the induction disc.

On 2/13/25, CW received the failed, CW supplied GE time delay relay from Constellation.

Further research discovered that LaSalle had a similar failure in 2002, but there have not been any other reported failures in the nuclear industry until this one.

On 4/07/25, Revision 2 of the failure analysis written by Constellation Power Labs stated similar results as those of 12/10/24. The bracket, even when fully tightened, could not hold its position on the shaft. The root cause of the failure could not be determined.

Because CW cannot establish a root cause, the following checks are recommended:

1) CW has modified the dedication plan to apply mild vertical force to assure that the clamp is secure as part of the dedication process.

2) End users should provide a similar mechanical test to be sure that the clamp remains secure during periodic surveillance and maintenance activities.

These actions should preclude a possible recurrence of this failure mechanism.

Relay information:
Part number: 12IAV69A1A
Manufacturer's serial number: AIAV111700032
CW tag number: CJ678001
CW serial number: 03

Affected facilities: Unknown

Responsible Curtis-Wright representative:

Mark Papke
QA Manager
Curtiss-Wright
4600 East Tech Drive, Cincinnati, OH 45245

MANUAL REACTOR SCRAM

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

"On April 08, 2025, at 1607 CDT, River Bend Station (RBS) was operating at 81 percent reactor power when a manual reactor protection system (RPS) actuation was inserted due to the loss of all normal service water pumps. Standby service water initiated and operated as expected. The scram was uncomplicated and all other plant systems responded as designed. Immediately after the scram, a reactor water level 3 isolation signal was received as expected.

"Reactor pressure is being maintained by the main turbine bypass valves. Reactor water level is being maintained by condensate and main feed water. RBS is currently in mode 3. No radiological releases have occurred due to this event. The loss of all normal service water is currently under investigation.

"This 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 while 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.

"The NRC Resident Inspector has been notified."

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

RBS intends to maintain temperature and pressure and remain in mode 3 while the event is under investigation.