Event Notification Report for March 13, 2025

AGREEMENT STATE REPORT - UNABLE TO RETRACT SOURCE

The following information was received from the Minnesota Department of Health (MDH), Radioactive Materials Unit via email:

"On March 13, 2025, during a radiography exposure, the radiography crew noted that too much drive cable extended into the guide tube. The radiographer cranked in to investigate and was unable to return the source to the exposure device. The radiation safety officer (RSO) was notified, and the crew began expanding their boundaries. The RSO initiated source retrieval operations. After shielding the source with lead shot, and performing some tests, it was determined that the source had not disconnected and that the guide tube was not attached to the camera. The RSO then `jiggled the drive cable' and was able to crank the source back into the shielded position. The RSO estimates that the source was exposed for less than 1 hour.

"After investigation, the RSO determined that the guide tube was never properly secured to the quick connect at the end of the exposure device. Cranking the source out to the end of the guide tube disconnected the guide tube from the exposure device. When retracting the source, the source pigtail caught on the quick connect port on the end of the exposure device due to the weight of the guide tube on the drive cable. To determine if the source was still connected, the RSO pulled on the controls and thus the drive cable and pig tail were pulled out of the guide tube. With the weight of the guide tube now off of the drive cable, the RSO was able to jiggle the controls and dislodge the pigtail from the quick connect at the end of the exposure device and retract the source completely.

"MDH was notified of the event on March 18, 2025, at approximately 1350 [CDT]. MDH is considering enforcement action due to the late notification of the event. An on-site investigation is planned for March 20, 2025.

"The device is a Source Production and Equipment Company (SPEC) model 150 radiography camera."

Minnesota Event Report ID: MN250002

AUTOMATIC ACTUATION OF '4B' EMERGENCY DIESEL GENERATOR

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

"At 1847 EDT on 3/13/25, with Unit 4 in mode 6 and defueled, an actuation of the 4B emergency diesel generator (EDG) occurred when the Unit 4 startup transformer '4B' 4kV Bus Supply Breaker '4AB05' tripped open. The '4B' EDG automatically started and energized the '4B' 4kV Bus as designed when the undervoltage condition caused the '4B' sequencer loss of offsite power signal to be received.

"This event is being reported pursuant to 10 CFR 50.72(b)(3)(iv)(A).

"The NRC Resident Inspector has been notified."

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

All systems responded as expected for the loss of voltage. There was no impact to the health and safety of the public or plant personnel. The cause of the breaker opening is under investigation. Power remains available to the '4B' 4kV Bus via both the '4B' EDG and the station blackout tie bus.

FITNESS FOR DUTY

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

A licensed employee had a confirmed positive test for alcohol during a test specified by the FFD testing program. The employee's access to the site has been terminated.

The NRC Resident Inspector has been notified.

FITNESS FOR DUTY

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

A licensed employee violated the FFD policy. The employee's access to the plant has been terminated.

The NRC Resident Inspector has been notified.

EN Revision Imported Date: 3/17/2025

EN Revision Text: UNUSUAL EVENT - LOSS OF OFFSITE POWER

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

"At 1902 EDT on 3/13/2025 Turkey Point Nuclear Plant Unit 4 declared an Unusual Event due to a loss of offsite power [to the '4B' 4KV bus]. The '4B' 4KV bus was re-energized from the '4B' emergency diesel generator (EDG). The '4A' 4KV bus is de-energized as part of the pre-planned outage scope. The cause of the loss of Unit 4 startup transformer is not known at this time. All plant parameters are stable."

State and local agencies were notified. The NRC resident inspector has been notified.

Notified DHS SWO, FEMA Operations Center, CISA Central Watch Officer, FEMA NWC, DHS Nuclear SSA (email), CWMD Watch Desk (email).

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

The licensee is evaluating the startup transformer before transferring the '4B' 4KV bus back to offsite power. Spent fuel pool cooling remained in-service as it was powered from Unit 3. Unit 3 was unaffected and remains at 100 percent power.

* * * UPDATE ON 03/13/2025 AT 2318 EDT FROM DANIEL BITTNER TO KERBY SCALES * * *

"At 2056 EDT on 3/13/2025, Turkey Point Nuclear Station Unit 4 terminated the Unusual Event due to a loss of offsite power. The event was terminated due to more than one emergency power source being available; `4B' emergency diesel generator and `4D' bus station blackout tie."

Notified R2DO (Pearson), DHS SWO, FEMA Operations Center, CISA Central Watch Officer, FEMA NWC, DHS Nuclear SSA (email), CWMD Watch Desk (email).

* * * RETRACTION ON 03/14/2025 AT 0518 EDT FROM DANIEL BITTNER TO JORDAN WINGATE * * *

"Turkey Point Nuclear Station Unit 4 is retracting this notification based on additional information not immediately identified at the time of notification. Following the loss of the '4B' 4kV bus event on 3/13/25, the emergency action level (EAL) technical bases document for CU2.1 was reviewed and identified that more than one emergency power source was still available at the time of the event and could have been credited. Specifically, the '4B' EDG and the '4D' bus station blackout cross tie (powered by Unit 3) emergency power sources were still available. The initial report was based on the available information at the time pursuant to emergency declaration and reporting notification requirements.

"The NRC Resident has been notified."

Notified R2DO (Pearson), Region 2 RA (Miller), NRR (Bowman). IR MOC (Crouch), Region 2 PAO (Gasperson), NRR EO (Felts), and NSIR (Erlanger)