Event Notification Report for March 20, 2025

LOST AND RECOVERED PET CAMERA

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

The licensee reported that on March 6, 2025, a positron emission tomography (PET) camera with a 1490 microcurie germanium-68 sealed source was inadvertently shipped offsite without first removing the source. The licensee discovered that the source was unaccounted for on March 10, 2025, and concluded that it had been inadvertently shipped offsite with the camera. On March 13, 2025, the licensee's vendor for the camera located the camera in a vendor-contracted warehouse in Cudahy, WI. The vendor warehouse is not a licensed radioactive materials facility. Vendor personnel (field services engineer and health physicist) inspected the camera, which was secured in its storage container with the source in the shielded position, and determined there was no radiological impact. The vendor personnel secured the camera in a locked location at the warehouse and made warehouse personnel aware of the camera's location. The vendor is making arrangements to retrieve the camera.

The licensee plans to notify the NRC Region 3 office. The vendor will be notifying the State of Wisconsin.

THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

FITNESS FOR DUTY

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

"At 1059 [CDT] on March 18, 2025, it was determined that a licensed operator failed a [random] test specified by the fitness-for-duty testing program. The individual's authorization for site access has been terminated.

"The NRC Resident Inspector has been notified."

SECONDARY CONTAINMENT BOUNDARY INOPERABLE

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

"At 1026 [EDT] on March 18, 2025, it was discovered that the secondary containment boundary door was found fully open, rendering the secondary containment boundary inoperable, therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72 (b)(3)(v). The door was closed at 1029 on March 18, 2025, and the secondary containment boundary was declared operable.

"There is no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified.

"There has been no impact to Unit 2 and Unit 3 continues to operate at 100 percent power."

FAILED FITNESS FOR DUTY TEST

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

"At 0930 EDT, March 18, 2025, it was determined that a contract supervisor failed a [random] test specified by the fitness-for-duty testing program. The individual's authorization for site access has been terminated.

"The NRC Resident Inspector has been notified."

AUTOMATIC REACTOR SCRAM

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

"At approximately 1136 CDT on March 19, 2025, with Unit 1 in mode 1 at 97 percent power, a reactor water level transient occurred which resulted in an automatic reactor scram on low reactor pressure vessel water level. The scram was uncomplicated with all systems responding as expected. The cause of the event is under investigation. Containment isolation valves actuated and closed on a valid group 2 signal.

"Operations responded and stabilized the plant in mode 3. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves.

"This event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) due to the reactor protection system actuation while critical, and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) for the Group 2 isolation signal.

"There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified. The state of Minnesota as well as Wright and Sherburne counties will be notified."

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

At the time of the event, condensate flushing evolutions were ongoing. It should be noted that prior to the reactor scram, a single feedwater pump tripped which would lower reactor water level.