Event Notification Report for August 01, 2025

AGREEMENT STATE REPORT - MEDICAL EVENT

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

"The Agency was contacted on July 23, 2025, by Rush University Medical Center in Chicago to advise of an administration of Y-90 Theraspheres which resulted in an underdose exceeding 20 percent. The incident occurred on July 22, 2025. No untoward medical impact to the patient is expected.

"The Agency was contacted by the radiation safety officer for Rush University Medical Center (radioactive materials license: IL-01766-01), on July 23, 2025, to report that a patient prescribed 47.42 mCi of Y-90 Theraspheres on July 22, 2025, received only 36.81 mCi of the prescribed dose.

"The patient has been notified, and inspectors will verify that the referring physician was notified during a reactive inspection scheduled to occur on July 29, 2025. There was no reported adverse impact to the patient. The licensee reported using a smaller than recommended catheter due to the area being treated. The underdose (22.4 percent deviation between the prescribed and administered dose) meets the criteria as a reportable event under 32 Illinois Administrative Code 335.1080. The prescribed and administered dose (in terms of Gy) will be confirmed on site. The investigation remains ongoing. This medical event will be reported to the NRC Operations Center today, July 24, 2025."

Illinois item number: IL250029

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

AGREEMENT STATE REPORT - POTENTIAL OVER EXPOSURE

The following report was received by the Georgia Radioactive Materials Program via email:

"The licensee's radiation safety officer called and stated that, during a high dose rate procedure, the nurse got stuck in the vault and was behind the CT [computed tomography] lead shielding. The licensee plans to send out her dosimetry badge to be processed for dose received and perform a pregnancy test.

"[The Georgia Radioactive Materials Program] will follow up with more information as we receive it."

Additional information: The equipment involved was a GammaMedPlus 3/24iX remote brachytherapy afterloader containing a Ir-192 source with an activity of 3.158 curies.

Georgia Incident Number: 104

AGREEMENT STATE REPORT - DAMAGED TROXLER GAUGE

The following information was provided by the Maryland Department of the Environment (MDE) via email:

"On July 25, 2025, at approximately 1520 EDT, the radiation safety officer (RSO) of Engineering Consulting Services Mid-Atlantic, LLC (ECS) reported an incident to MDE involving damage to a Troxler model 3440 portable nuclear gauge (serial number 30580). The incident occurred at a construction site located in Frederick, MD.

"According to the gauge technician, the roller operator initially passed the technician on the right side and then reversed the roller toward the testing site. Despite immediate attempts to alert the driver to stop, the roller continued reversing. Once the gauge operator realized the driver was not stopping, he quickly moved out of the roller's path. The gauge was subsequently struck by the roller.

"As reported by the RSO, while the gauge housing was damaged, there is no indication of a breach of the radioactive sources' integrity. The RSO conducted leak tests immediately after the incident and submitted the samples to North East Technical Services Inc. (NETS) for analysis. Results are currently pending. MDE has requested the licensee to transfer the damaged gauge to NETS as per the safety protocol and provide the leak test results, calibration records, and appropriate transfer and/or disposal documentation once the evaluation by NETS is complete. Decisions regarding repair or disposal of the gauge will be based on NETS' findings.

"Following removal of the gauge from the site, a radiation survey was conducted, and no elevated radiation levels above background were detected as per the RSO. MDE's radiological health program will continue to monitor and follow up on this reactive investigation until the device is either repaired or appropriately disposed of."

AUTOMATIC REACTOR TRIP

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

"On July 30, 2025, at 1230 CDT, with Unit 1 in mode 1 at 100 percent power, the reactor automatically tripped due to an over temperature delta 'T' 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).

"Actuation of the auxiliary feedwater [system] occurred during the reactor trip response. The cause of the auxiliary feedwater auto-start was a LO-2 steam generator water level. The 1A and 1B auxiliary feedwater pumps started as designed when the LO-2 steam generator water level signal was received. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the auxiliary feedwater system. Operators responded using procedures 1BwEP-0 and 1BwEP ES-0.1 to stabilize the unit in mode 3.

"Decay heat is being removed by discharging steam to the main condenser using the main steam dump valves. Unit 2 is not affected. All systems responded as expected with the exception of steam pressure channel 1Pl-545A and steam flow channel 1Fl-523A, which both failed high during the lightning storm and subsequent transient. Actions per 1BwOA lnstrument-2 are in progress to address these failures.

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

"The NRC Resident Inspector has been notified."

INVALID ACTUATION OF PRIMARY CONTAINMENT ISOLATION SYSTEM (PCIS) GROUP 6

The following information was provided by the licensee via phone and 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 actuation of a general containment isolation signal affecting more than one system.

"On May 30, 2025, during de-inerting of the Unit 2 drywell for a forced outage, Unit 2 received a partial primary containment isolation system (PCIS) group 6 isolation. Additionally, standby gas treatment system (SGT) trains `B' and `C' auto started.

"Plant conditions which initiate PCIS group 6 and SGT actuations are reactor vessel low water level (Level 3), high drywell pressure, or reactor building ventilation exhaust high radiation (reactor zone or refuel zone). At the time of the event, these conditions did not exist; therefore, the actuation of the PCIS and SGT was invalid.

"Upon investigation, a fuse was found to have failed as a result of a hot spot due to a corroded lug, which was the cause of the isolation. The fuse was replaced, [lug cleaned], condition was cleared, and all systems were realigned as necessary.

"There were no safety consequences or impact to the health and safety of the public as a result of this event.

"This event was entered into the Corrective Action Program as Condition Report 2017035.

"The NRC Resident Inspector has been notified of this event."

POTENTIAL INOPERABILITY OF RESIDUAL HEAT REMOVAL (RHR) SYSTEM

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

"At 1645 CDT on July 30, 2025, it was discovered that the single train of the ultimate heat sink was inoperable. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(B).

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

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

The proximal cause of the inoperability was due to a buildup of grasses in the crib house from the river. Operators were able to clear the crib house bar rack intake and restore operability within eight minutes.