Event Notification Report for October 01, 2026

EN Revision Imported Date: 10/1/2026

EN Revision Text: PART 21 - FUEL POOL STORAGE CRITICALITY CALCULATION ERROR

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

Westinghouse has discovered a deviation in its fuel data management system that has potential to affect the criticality calculations for fresh fuel with integral fuel burnable absorbers (IFBAs) in the spent fuel pool. The system allows the use of facility-specific curves to determine when a fresh fuel assembly with IFBAs is acceptable for storage in the spent fuel pool. When the system adjusts for an IFBA loading different from what was used to develop the facility-specific curve, there is potential for the assessment to allow storage of fuel with IFBA loading that is not encompassed by the fuel storage criticality analysis of record.

Currently, Westinghouse has not identified an existing condition where the system has allowed fuel to be stored in a manner that is not encompassed by the fuel storage criticality analysis of record for the potentially impacted plants listed below. The affected customers have been notified. Westinghouse expects to complete its 10 CFR Part 21 evaluation on or before September 30, 2026.

The following plants are potentially affected: Cook, Diablo Canyon, Farley, Millstone, Point Beach, Salem, Turkey Point, Summer, South Texas, Vogtle, Wolf Creek

Designated contact:
Andrew Bowman
Manager, Global Nuclear Regulatory Affairs
Westinghouse Electric Company
1000 Westinghouse Drive
Cranberry Township, PA
Email: bowmanab@westinghouse.com
Office: 412-374-2363

* * * UPDATE ON 09/30/2026 AT 0814 EDT FROM ANDREW BOWMAN TO ROBERT THOMPSON * * *

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

Westinghouse is providing this update pursuant to the requirements of 10 CFR 21.21(d).

Westinghouse performed representative analyses to assess the impact of the identified deviation for typical fuel storage configurations recognizing that the storage rack analyses are not generically applicable across different plants. The evaluations examined increasing and decreasing IFBA loading for different potential loading combinations. Westinghouse determined that, were the deviation to remain uncorrected, the TracWorks system could potentially permit storage configurations of fresh IFBA-containing fuel assemblies that in conjunction with a potential abnormal condition could potentially result in a substantial safety hazard.

This issue only affects plants that are using the TracWorks system with burnup credit curves defined in the plant database and one or more storage curves that contain IFBA credit. There are no safety concerns if the affected licensees do not have fresh fuel stored in their storage racks.

Westinghouse is taking action to determine and implement updated software requirements for IFBA conversion into the TracWorks system by the fourth quarter of 2026. As an interim measure, Westinghouse has implemented a user warning into the TracWorks system to alert users of the potential nonconservative results when using the fresh fuel IFBA credit for storage.

The following additional plants are potentially affected: Sequoyah.

Notified Regions 1-4 Reactors Groups (email), Part 21 Reactors Group (email)

EN Revision Imported Date: 10/1/2026

EN Revision Text: AGREEMENT STATE REPORT - DOSE TO EMBRYO

The following information was received from the New York State Department of Health (NYSDOH), Bureau of Environmental Radiation Protection via email:

"On September 22, 2026 at 1300 EDT, NYSDOH was notified of a possible reportable event under 10 CFR 35.3047.

"A female patient was treated for hyperthyroidism (29.4 mCi of I-131) on August 19, 2026. In accordance with standard clinical protocols, the patient was tested for potential pregnancy as part of the patient selection process for these procedures. This test returned `negative' and the treatment was authorized in accordance with standard procedures and protocols.

"The patient contacted the licensee this morning to notify them that she is pregnant and was likely pregnant at the time of the procedure. The patient was estimated at 3-4 weeks pregnant at the time of this procedure. The dose received is assumed to be greater than the reporting limits provided in 10 CFR 35.3047 but is going to be provided in writing as licensee staff are continuing to validate dose calculations.

"According to the radiation safety officer, everything was administered in accordance with standard hospital procedures, and notifications have been made to the authorized user, referring physicians, and the obstetrician/gynecologist for the patient. It was discussed that adverse impact to the patient or the embryo is not expected from this procedure, as the fetal thyroid gland commences development around the fourth week of pregnancy and hormonal development commences around as early as week 10. Physician opinion at this time indicates that the greatest risks to the embryo development mostly derive from the existing patient's condition (hyperthyroidism) and not necessarily the treatment in question.

"The licensee is going to be submitting a written notification within fifteen (15) days in accordance with 10 CFR 35.3047(d), and providing a copy of this report to the referring physician in accordance with 10 CFR 35.3047(f).

"This incident is being tracked under incident number 1571. NYSDOH is monitoring this event and will provide updates to the U.S. NRC as soon as available."

NY event report ID: NY-26-05
NY incident number: 1571

* * * UPDATE ON 9/30/2026 AT 0814 EDT FROM NATHANIEL KISHBAUGH TO SAMUEL COLVARD * * *

The following information was received from the New York State Department of Health (NYSDOH), Bureau of Environmental Radiation Protection via email:

"On September 29, 2026, the licensee provided a written report in accordance with 10 CFR 35.3047(d). This report confirmed the information provided during the original telephone report and provided detailed dose reconstruction for fetal/embryo dose. Based on the administration amount of 29.4 mCi (1.088 GBq) I-131 via orally administered NaI capsule, the expected fetal dose is 78 mGy. It is noted that the physician indicated that, due to the very early gestational age (i.e., before 10 weeks), no fetal thyroid effects are anticipated. Stochastic risks using ICRP 84 'Pregnancy and Medical Radiation' are expected to be very small from this event (decrease of 99.7 percent to 99.4 percent for 50 mGy fetal exposure, theorized to increase linearly with dose). The pregnant patient has been notified and counseled, and their referring physician has also been notified of this event. No additional medical intervention from this event has been deemed necessary.

"The information provided indicates that this event occurred due to the limitations in pregnancy test results/accuracy in very early stages and patient unawareness of pregnancy. Prior to treatment, the patient was counseled to avoid pregnancy for six months following I-131 treatment, which prompted the patient to contact the licensee following their awareness of being pregnant. No corrective actions or preventative measures appear appropriate for the licensee, as the circumstances leading to this event appear to primarily root from limitations in pregnancy tests and patient awareness of pregnancy during treatment.

"The written report, investigation, and findings have been accepted by NYSDOH. Subsequently, Incident 1571 has been closed."

Notified NMSS Event Notification (email)

AGREEMENT STATE REPORT - LOST SOURCE

The following is a summary of information provided by the Colorado Department of Public Health and Environment, via email:

Two static eliminators were declared lost by the licensee on September 16, 2026. The static eliminators were manufactured by NRD LLC (model numbers P-2021), with 0.1 Ci of Po-210 (polonium) activity each.

Colorado Event Report ID Number: CO260022

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

AGREEMENT STATE REPORT - LEAKING SOURCE

The following is a summary of information provided by the South Carolina Department of Environmental Services (the Department) via phone and email:

On August 28, 2026, the licensee reported that a 555 MBq (15 mCi) Ni-63 source was leaking. The source was part of a Perkin Elmer electron capture detector (ECD) (serial number 1488). A routine wipe test of the ECD was performed on July 26, 2026, with results indicating that the ECD had 222 Bq (0.006 uCi) of removable contamination wiped from the entrances port. The ECD was sent to Detector Service Center, LLC (North Carolina radioactive material license number 092-0660-1) for repair and was received back on August 24, 2026.

The licensee did not report any overexposures or ongoing health/safety concerns. This event is still under investigation by the Department.

South Carolina Event Number: SC260005

AGREEMENT STATE REPORT - STOLEN TROXLER GAUGES

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

"On September 24, 2026, a radioactive material inspector identified that OHLA Central, Inc. (IL-02482-01) failed to report to the Agency regarding two Troxler 3440P gauges stolen from a temporary jobsite located in Hinsdale, IL on June 30, 2025. The two gauges contained both Cs-137 (8 mCi) and Am-241(40 mCi) as of 6/20/17 for gauge, serial number 72854, and as of 6/12/2024 for gauge, serial number 88888.

"The licensee filed a police report and notified the manufacturer, Troxler Electronic Laboratories, Inc., on June 30, 2025.

"The licensee will be cited for failure to report the stolen gauges to the Agency as required by 340.1210 and failure to submit the required 30-day written report. This event also requires immediate reporting to U.S. Nuclear Regulatory Commission and notification has been made. The inspection will continue to determine root cause and confirm implementation of appropriate corrective actions."

Illinois Reference Number: IL260025

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