Event Notification Report for February 05, 2025

AUTOMATIC REACTOR TRIP

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

"At 1002 EST, on February 5, 2025, with Unit 2 in mode 1 at 100 percent power, the reactor automatically tripped due to lowering 'B' steam generator level. All control rods fully inserted into the core and the auxiliary feedwater system automatically started as designed in response to the full power reactor trip. The trip was not complex, with all systems responding normally post-trip. There was no equipment inoperable prior to the event that contributed to the reactor trip or adversely impacted plant response.

"Operations responded and stabilized the plant. Decay heat is being removed by discharging steam to the main condenser using the condenser steam dump valves. Unit 1 is not affected and remains at 100 percent power and stable. 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). Additionally, this event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in a valid actuation of the auxiliary feedwater system.

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

FITNESS FOR DUTY

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

A non-licensed employee supervisor had a confirmed positive during a random fitness for duty test. The employee's unescorted access to the plant has been revoked.

The NRC Senior Resident Inspector has been notified.

AGREEMENT STATE REPORT - LOST I-125 SEED

The following information was provided by the Illinois Emergency Management Agency (the Agency) via phone and email:

"The Agency was contacted on 2/13/25, by the University of Chicago to report the inadvertent disposal of a an I-125 brachytherapy seed down the facility's sink drain. The loss is believed to have occurred during sterilization prior to implant on 2/5/25. Five extra sterilized and packaged I-125 seeds were brought to the facility's radiation oncology department in the event they were needed for the procedure. The extra seeds were not needed and the unopened package was taken to the source storage room. It is unclear if surveys of the unused seeds were performed as required. On 2/12/25, the package believed to contain the five I-125 seeds was opened and found to be empty.

"Radiation safety staff surveyed applicable areas and located four of the five seeds in the sterilization area's sink drain. The fifth seed was not located and is being reported as lost, with the likely disposition of being inadvertently disposed of via the sanitary sewer.

"The brachytherapy seed has decayed to approximately 0.344 millicuries and would have an exposure rate of just over 2 millirem per hour at six inches. [The original activity of the I-125 brachytherapy seed was 0.405 millicuries.] The loss is reportable to the U.S. NRC within 30 days. Agency inspectors will conduct a reactive inspection to determine root cause and measures taken to prevent a recurrence. This report will be updated as additional information becomes available."

Illinois Item Number: IL250006

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