Event Notification Report for June 01, 2026

EN Revision Imported Date: 5/29/2026

EN Revision Text: MEDICAL EVENT

The following information was provided by the licensee via phone:

On May 21, 2026, at 1203 EDT, a Y-90 TheraSphere treatment was ordered for a patient. The doctor prescribed an activity of 3.98 GBq for a desired dose of 65 Gy to the liver. After administration, the activity received was calculated to be 3.68 GBq (92.5 percent of the prescribed activity). However, the calculation for activity delivered to the perfuse liver tissue (i.e. tumor) was 3.14 GBq, 78.7 percent of the prescribed activity.

The authorized user and the health physicist were notified.

* * * RETRACTION ON 05/28/2026 AT 1058 EDT FROM KIM LOWE TO ROBERT THOMPSON * * *

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

The licensee reported that further evaluation of the event showed that a portion of the administered activity had shunted to the lungs. The licensee is therefore retracting the event after review of the reportability requirements in the applicable licensing guidance. The patient and treatment location had been evaluated for possible shunting pathways prior to the treatment in accordance with licensing guidance, greater than 90 percent of the planned activity was administered to the patient, and only 14.6 percent of the activity shunted to the lungs.

Notified R1DO (Warnek), NMSS Events Notification (email).

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.

EN Revision Imported Date: 5/29/2026

EN Revision Text: FITNESS FOR DUTY

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

"On May 28, 2026, at 1109 CDT, it was determined that a non-licensed supervisor failed a test specified by the FFD testing program. The individual's authorization for site access has been terminated at South Texas Project. This has been determined to be reportable under 10 CFR 26.719(b)(2).

"The NRC Resident Inspector has been notified."

PART 21 - INCORRECT LENGTH OF SPENT FUEL POOL TRANSFER CANAL SEALS

The following information was provided by the licensee via email:

"Southern Nuclear Operating Company (SNC) has determined there is evidence of two Pawling Engineered Products (Pawling EP) spent fuel pool transfer canal seals (SNC part numbers 609100 and 1433155) being of incorrect length for proper installation. The lengths did not meet the specifications of the purchase order, nor did they match the documentation received.

"The evaluation of the deviation determined that a substantial safety hazard could have been created by the incorrect lengths in the Pawling EP spent fuel pool transfer canal seals utilized at Edwin I. Hatch Nuclear Plant (HNP) if they were installed and left uncorrected. While the nature of the seal length errors had the potential to impact spent fuel pool water level, SNC has verified that none of the nonconforming seals had been used at HNP and were instead returned to the vendor for remediation.

"The NRC Senior Resident Inspector has been notified."