Event Notification Report for April 12, 2023

AGREEMENT STATE REPORT - STUCK SHUTTER

The following is a summary of information provided by the Kentucky Department of Radiation Control via email:

On April 4, 2023, an authorized gauge user identified a shutter stuck open on a gauge mounted 15 feet up in the air on a coal feeder at the D.B. Wilson power plant. The shutter opened and closed; however, when the shutter was placed into a closed position some radiation exposure was still present outside the shutter. The gauge is model number 7062BP, serial number 17777, with 100 mCi Cs-137. The Radiation Safety Officer (RSO) alerted employees of the stuck shutter. The gauge will remain in place until a certified contractor can remove it. The contractor is expected to arrive on April 5, 2023.

* * * UPDATE ON 4/6/2023 AT 1254 EDT FROM CURT PENDERGRASS TO IAN HOWARD * * *

The following information was provided by the Kentucky Department of Radiation Control via email:

"According to the RSO, RAM Services, Inc. was able to free up the shutter yesterday, but there were issues with elevated exposure rates so the decision was made to dispose of the device and package it for shipping."

Notified R1DO (Gray) and NMSS Events Notification.

AUTOMATIC REACTOR TRIP

The following information was provided by the licensee via email:

"At 0048 EDT on 4/10/2023, with Unit 3 in Mode 1 at 18 percent power, the reactor automatically tripped due to low reactor coolant flow due to voltage decaying to the reactor coolant pumps during main generator testing activities. The trip was not complex, with all safety-related systems responding normally post-trip.

"Operations responded and stabilized the plant. Decay heat is being removed by discharging steam via steam generator power operated relief valves to atmosphere. Units 1, 2, and 4 are 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).

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

60 DAY NOTIFICATION FOR AN INVALID ACTUATION OF THE EMERGENCY SERVICE WATER SYSTEM

The following information was provided by the licensee via email:

"This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid specific system actuation of the Emergency Service Water (ESW) System.

"On 2/16/2023, while performing a calibration planned maintenance (PM) for a jacket water pressure indicator during a D13 diesel generator system outage window, the 'C' ESW pump unexpectedly auto-started. Subsequent investigation identified that the affected jacket water pressure indicator shares a common sensing line with a jacket water pressure switch that provides a back-up to the engine speed switch for the engine running signal. At the time the jacket water pressure indicator calibration PM was being performed, the power circuits for D13 diesel generator instrumentation were energized. Pressurization of the energized jacket water pressure switch during the pressure indicator calibration activity resulted in initiation of a false engine running signal to the `C' ESW pump start logic.

"This event is considered an invalid system actuation because the 'C' ESW pump started in response to a false signal that the D13 EDG was running when the D13 EDG did not start. The actuation was not initiated in response to actual plant conditions or parameters and was not a manual initiation. The ESW system functioned as expected in response to the actuation. The affected ESW pump was shut down in accordance with plant procedures. There was no impact on the health and safety of the public or plant personnel."

The licensee notified the NRC Resident Inspector.