Event Notification Report for September 21, 2026

EN Revision Imported Date: 9/21/2026

EN Revision Text: AGREEMENT STATE REPORT - EQUIPMENT MALFUNCTION

The following is a summary of information provided by the California Department of Public Health, Radiologic Health Branch (RHB) via email:

On September 8, 2026, at approximately 1220 PDT, during high-dose-rate (HDR) brachytherapy treatment for a facial tumor, the HDR unit failed to retract the Ir-192 source after the intended exposure. Facility staff immediately recognized the unit's position alarm, entered the procedure room, evacuated the patient, and placed the source into the emergency lead container. The patient was in close proximity to the source for approximately 84 seconds before removal, resulting in an unintended additional dose.

The radiation safety officer is conducting dose assessments for both the patient and the staff who responded during the event.

A site visit is scheduled for September 10, 2026.

5010 number: 090926

* * * UPDATE ON 09/18/2026 AT 1734 EDT FROM L. ROBERT GREGER TO CHRISTOPHER PRESCOTT * * *

The following is a summary of information provided by the California Department of Public Health, Radiologic Health Branch (RHB) via email:

The RHB received additional information from the licensee (Northridge Hospital) that the patient received an inadvertent dose of 370 rad. This makes the event also reportable as a medical event.

Notified NMSS Events Coordinator (Allen), and NMSS Event 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: 9/21/2026

EN Revision Text: AGREEMENT STATE REPORT - FOUND ORPHAN GAUGES

The following is a summary of information provided by the Texas Department of State Health Services (the Department) via phone and email:

On September 11, 2026, the Department received a notification from Vega Americas, Inc. regarding two radioactive gauges discovered on a fracking blender trailer acquired by J-Mac Completion, a Fort Worth-based company. The trailer, along with an attached truck, had been purchased at an equipment auction held on October 25, 2025.

Two devices were found attached to the trailer:
-- Thermo Fisher gauge of unknown activity and model (no visible markings)
-- Vega SHLD-1 gauge, S/N: 77970G, containing a 52 mCi Cs-137 source (as of January 1, 2020)

Vega reported that the SHLD-1 device was originally distributed as a generally licensed device to NRG Energy. It was later integrated into the trailer, which subsequently came into possession of Catalyst Energy Services. In October 2025, Catalyst consigned the blending trailer to Machinery Auctioneers for disposal.

J-Mac Completion is not licensed by Texas, the NRC, or any Agreement State. The company had not accessed the trailer until recently, when personnel noticed the gauges. The trailer has been stored in an isolated portion of J-Mac's facility, and based on current information, no exposures to individuals have occurred. An investigation is in progress.

Texas incident number: I-10327

* * * UPDATE ON 09/18/2026 AT 1528 EDT FROM BRUCE HAMMOND TO CHRISTOPHER PRESCOTT * * *

The following was information provided by the Texas Department of State Health Services (the Department) via email:

"On September 16, 2026, the Department is able to confirm the manufacturer, model, serial number, isotope, activity and calibration date of the second gauge reported. The gauge is a Thermo Fisher model 5192, containing [a 200 mCi Cs-137 source] (original activity July 2018)."

Notified NMSS Event Notification (email)

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

PART 21 - CIRCUIT BREAKER DEFECT

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

On July 9, 2026, ABB Florence was notified by NextEra Energy of a defect discovered during inspection prior to installation of a K-Line K-600 circuit breaker. A cotter pin was found missing from the breaker paddle. ABB's engineering evaluation confirmed that the missing cotter pin could compromise the breaker's ability to perform its intended safety function.

ABB has completed a thorough investigation to determine if this issue affects other circuit breakers or customers and found that this condition is isolated to nine breakers pertaining to a single order of 30 pieces supplied to Seabrook Station. No other orders or customers were affected.

To resolve this issue, and in accordance with customer instructions, ABB will provide replacement cotter pins with installation instructions. As a preventive action, ABB has added quality checkpoints during production and a final inspection to confirm the installation of the cotter pins.

Affected plant: Seabrook Station

Responsible ABB Inc. Representative:
Percy Isaac
Plant Manager
ABB Inc.
2300 Mechanicsville RD
Florence, SC 29501

PART 21 - BATTERY CELL VOLTAGE ISSUE

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

"On September 10th, 2026, Cook Nuclear Plant (CNP) completed a Part 21 evaluation concerning a voltage issue involving 1-BATT-CD plant battery, cell 50, in Unit 1. The affected [battery cell] is a C & D Technologies Inc. model LCR-33 NUC, manufactured in February 2016.

"During a quarterly surveillance test of the Unit 1 'CD' battery, cell 50 was found to have a voltage below the required technical specification (TS) limit. In accordance with CNP procedures, an attempt was made to restore the cell voltage to above the TS requirement. However, the cell did not hold its charge and the voltage degraded; it was replaced one week later.

"If this condition were present in multiple cells simultaneously, it could pose a substantial safety hazard due to the potential loss of required battery capacity or the failure of the battery to maintain its required mission time during a station blackout event. C&D Technologies Inc. reported that the low-voltage condition was caused by an internal short within the cell. The short prevented the cell from maintaining a stable current during charging. Failure analysis revealed a paste lump that had penetrated the separator and contacted the adjacent negative plate, causing the failure.

"This failure mode cannot be visually identified and is detectable only through the routine collection and evaluation of cell voltage data. The defect cannot be detected until the electrical short occurs. CNP is taking weekly battery terminal voltage [readings].

"A written notification will be provided within 30 days.

"Cook Nuclear Plant is the only facility known to be affected at the time of this report.

"The NRC Resident Inspector has been notified."

AGREEMENT STATE REPORT - MEDICAL EVENT

The following is a summary of information provided by the California Department of Public Health, Radiologic Health Branch (RHB) via email:

On September 11, 2026, a liver cancer patient was administered two vials of Y-90 TheraSpheres to liver "segment 3" at UCLA Health Ronald Reagan Medical Center. The prescribed dose for was 500 Gy and the dose delivered was 879 Gy (175.8 percent of the prescribed dose).

The administering physician observed, while flushing saline through the catheter, that the reading on the electronic dosimeter placed in front of the Y-90 TheraSphere vial to monitor the administration process was unchanged after the injection. The electronic dosimeter should read 0 mR/h after dose administration.

The administering physician determined that no activity had been delivered, and it was decided that a second vial should be administered at the same location. After administering the activity and flushing saline through the catheter, the physician observed that the electronic dosimeter was still unchanged. It was then observed that the dosimeter was set to "cumulative mode" instead of "exposure rate mode," and therefore would not display a change in the reading. Recognizing that the first vial may have been administered, the exposure rate of the first waste container was measured and indicated that approximately 90 percent of the activity in the first vial had been administered.

California 5010 incident number: 091126

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.

PART 21 - RELAY CONTACTS SLOW TO CHANGE STATE

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

In early July 2026 HB Robinson identified the relay contacts of a single Tyco relay would not properly actuate. Bench testing by Robinson indicated greater than 1 megaohm across relay contacts when the relay coil was energized and based on those results Robinson concluded that the expected contact transition was not occurring. Robinson returned the relay to Curtiss-Wright.

Curtiss-Wright testing found that the contacts did transition when the relay actuated but observed that a noticeable time delay was identified in the transition of the normally open contacts. Lag times ranged from 479 to 1,500 milliseconds. The relay was returned to Tyco for further evaluation to determine whether the measured response time represents acceptable product performance or is indicative of an abnormal condition or degradation within the relay. This evaluation is still ongoing, however Curtiss-Wright intends to have the final evaluation and report completed by November 17, 2026.

Affected plant: HB Robinson

Tyco part number: E7012PB004, S/N 24240332
Curtiss-Wright tag number: CJ1900501 S/N: 02

Curtiss-Wright responsible manager
Mark Papke
QA Manager
Curtiss-Wright
4500 East Tech Drive
Cincinnati, OH 45245

UNUSUAL EVENT

The following information was provided by the licensee via phone:

On September 18, 2026, at 0727 MST, Palo Verde declared an Unusual Event (HU1.1) due to a security condition not involving hostile action.

Units 1, 2 and 3 are stable in mode 1 at 100 percent power.

State and local authorities were notified. The NRC Resident Inspector has been notified.

Notified DHS SWO, FEMA Operations Center, FEMA NWC, CISA Central Watch Officer, CWMD Watch Desk, DHS Nuclear SSA (email), DHS NRCC THD Desk (email).

* * * UPDATE ON 09/18/2026 AT 1231 EDT FROM FREDERIC MONTALDO TO SAM COLVARD * * *

The following information was provided by the licensee via phone:

On September 18, 2026, at 0921 MST, Palo Verde terminated the Unusual Event.

State and local authorities were notified. The NRC Resident Inspector has been notified.

Notified CNRI (Groom), IRMOC (Whited), ILTAB (Brown), PAO (Smith), R4 SLO (Alexander); NRR/DEPR (Waters), DHS SWO, FEMA Operations Center, FEMA NWC, CISA Central Watch Officer, CWMD Watch Desk, DHS Nuclear SSA (email), DHS NRCC THD Desk (email).

PART 21 - EMERGENCY DIESEL GENERATOR STARTING AIR COMPRESSOR FAILURES

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

Paragon Energy Solutions has determined a defect exists in Ingersoll Rand/Paragon compressors supplied to the DC Cook plant, part numbers H7100X10-MOD and H7100X15. DC Cook reported failures in four compressors used during emergency diesel generator startup. Paragon's initial analysis found that the second-stage valve plate gasket had failed, allowing gasket material to enter the valve seat. This created excessive back-pressure, lifting the first-stage relief valve, and reducing compressor discharge pressure below required performance. All compressors exhibiting this failure mode were manufactured in 2022 or later using an updated valve plate design.

Because this condition, if left uncorrected, could create a safety hazard, Paragon is submitting this initial notification in accordance with 10 CFR Part 21. The issue has been entered into Paragon's nonconformance reporting system, and replacement compressors equipped with the original valve plate design are being provided to DC Cook. Paragon is working with Ingersoll Rand to complete the root-cause evaluation. Paragon has recommended that DC Cook monitor in-service compressors for signs of degradation while the final Part 21 evaluation is completed.

Affected plant: DC Cook

Point of Contact:
Kenny Morrison
Vice President, Quality Assurance
Paragon Energy Solutions, LLC
KMorrison@paragones.com
817-284-0077