Event Notification Report for April 03, 2026

UNANALYZED CONDITION

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

"At 0924 EDT on April 1, 2026, it was determined that Unit 3 was in an unanalyzed condition because two emergency diesel generators (EDGs) were inoperable. One EDG was inoperable due to scheduled maintenance, and the second EDG was inoperable due to blocking for an emergent plant issue. This condition is not bounded by existing design and licensing documents; however, it poses no impact to the health and safety of the public or plant personnel. The second EDG was returned to service, and the condition was exited.

"This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(D).

"The NRC Resident Inspector has been notified."

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

Unit 2 was unaffected by this condition. No other limiting conditions exist. The second EDG was blocked due to a failed transformer, but the transformer has been repaired.

AGREEMENT STATE REPORT - MEDICAL EVENT

The following information was provided by the Connecticut Department of Energy and Environmental Protection via phone and email:

"On March 25, 2026, at 1511 EDT, a patient was planned for coronary brachytherapy for treatment to the proximal left circumflex coronary artery for an injury 30 millimeter (mm) in length and a target vessel mean luminal diameter of 3 mm. A proximal margin into the left main coronary artery and a distal margin further into the left circumflex vessel were also included. The planned treatment was to deliver 18.4 Gy at 2 mm depth using the 60 mm BetaCath source train. During catheter placement and wire test, the radiation oncologist (authorized user) noticed some friction in the catheter. Since the wire could still move through the catheter, the decision was made to attempt source deployment. Under fluoroscopy, it was observed that the 60 mm source did not fully deploy into the left circumflex but was stuck within the distal aspect in the left main coronary artery. This was likely due to an obstruction in the treatment catheter at the ostium of the left circumflex coronary artery where the left main coronary artery bifurcates at an acute angle in this patient. The radiation oncologist attempted to finish source deployment, which was unsuccessful.

"The source return to the transfer device was also unsuccessful. Emergency bailout was declared after approximately 16 seconds after sources arrived at the stuck location. After the device and treatment catheter were secured in the bailout box, the authorized medical physicist surveyed the patient, room, and bailout box and confirmed sources were located within the catheter in the bailout box. The decision was made to treat the patient with the 40 mm source, which was determined to provide adequate margin of the lesion, and a new treatment catheter was placed in the patient. After approval of the new treatment plan, and catheter wire test, the radiation oncologist attempted to deploy the 40 mm source, however this source also became stuck in the same location at the left circumflex ostium. The cardiologist pulled the treatment catheter back slightly to allow source return to the transfer device, which was successful. Dwell time at stuck position estimated at 16 seconds based on stopwatch time.

"The estimated dose was as follows:
40 mm: 0.058 Gy/sec x 16 sec = 0.928 Gy at 2 mm depth
60 mm: 0.059 Gy/sec x 16 sec = 0.944 Gy at 2 mm depth
Total dose (assuming full overlap of source trains): 1.872 Gy at 2 mm depth.

"The target lesion did not receive the intended treatment dose (18.4 Gy at 2 mm depth)."

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 - MEDICAL EVENT

The following is a summary of information provided by the New Jersey Radiation Protection and Reliability Prevention (NJDEP) Program via email:

Summit Health Cancer Center reported that a patient scheduled to receive a 200 mCi Lu-177 Pluvicto treatment only received 150 mCi. The underdose was due to either faulty or improperly connected tubing. The licensee is investigating and will forward a full report.

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.