Event Notification Report for August 17, 2026

EN Revision Imported Date: 8/17/2026

EN Revision Text: INTERIM PART 21 REPORT - VALVE ASSEMBLY MOTOR FAILURE

The following is a summary of information provided by ABB Motors and Mechanical (ABB) via phone and email:

Potential defects were identified in safety-related motors supplied via Flowserve. Flowserve and ABB were informed that during commissioning of a new SBD-3 actuator and valve assembly, the actuator motor failed to operate. A summary of a third-party failure analysis provided by Bruce Power indicated that the likely cause of the failure was attributable to mechanical interference between a rotor balance weight and the stator winding causing insulation damage and turn-to-turn short. To date, the subject motor has not been returned to ABB for inspection.

Affected Plants: Unknown

Component Information:
Component Type: Safety-related AC electric motors for motor-operated valve (MOV) applications.
Motor Serial Number: GG215020118 supplied to Flowserve Corp.- Limitorque Actuation.
Motor Identifier: Flowserve part# R-403-F03-080000A20
Description: 100 ft-lb, 3/60/575, 2-pole motor

Contact Information:
Sam Bosworth
ABB Motors and Mechanical Inc.
Interim Quality Manager
Office: (678) 947-7274
Email: sam.bosworth@us.abb.com
Address: 4349 Avery Drive, Flowery Branch, GA, 30542

* * * UPDATE ON 07/31/2026 AT 1705 EDT FROM SAM BOSWORTH TO KAREN COTTON * * *

The following information was provided by ABB via email:

"ABB continues to perform an extent of condition analysis to identify motor designs which could potentially be affected. Subsequently, a review of available borescope inspections of the motor lot size procured on this specific order was completed eliminating motors which could be visually verified to have no weights added to the rotor during the balancing process. As an engineering enhancement of the motor design, balance weights have been eliminated. Work instructions have been revised accordingly. Inspection checks have also been implemented to verify no balance weights have been used.

"ABB has identified seven motors at risk using several parameters including but not limited to ship date and inspection records. The list of motors below, identified by serial number, is being shared with our customer Flowserve for assistance identifying the location and end user of the motor. This information will be provided when available. It should be noted that if a motor has been in service and operating without issue there is minimal risk for this condition. ABB recommends performing a megger test on the following serial numbers which can be found on the motor nameplate. If utility has a defined preventative maintenance program for insulation resistance follow that protocol.

"Testing Guidance:
 Compare new megohm readings to historical baseline data
 Consistent readings confirm motor integrity
 For motors without baseline data: acceptable minimum is 5 megaohms (new condition)
 Results at or above baseline = Motor can be cleared from this nonconformance

"List of Motors
GG215120026
GG201320128
GG194420114
GG194020217
GG184220163
89160683-010-002
81199658-010-001

"This is the second Interim notification. Per the requirements of 10 CFR 21.21(d) a follow-up notification of evaluation status will be submitted on or before August 14, 2026."

Notified R1DO (Haney), Part 21 Reactors (email).

* * * UPDATE ON 08/14/2026 AT 1508 EDT FROM SAM BOSWORTH TO PHILIP ALIER * * *

The following information was provided by ABB via phone and email:

The extent of condition determination revealed that 150 ft-lb 2-pole, aluminum rotor construction motors could be affected, which have been evaluated accordingly.

This is the final notification report.

Notified R1 Reactor Events and Part 21 Reactors via email.

AGREEMENT STATE REPORT - STUCK SHUTTERS

The following information was provided by the Pennsylvania Bureau of Radiation Protection (the Department) via email:

"On July 1, 2026, at 1000 [EDT], the licensee's safety representative and a contracted technical specialist from Applied Health Physics, LLC notified the radiation safety officer (RSO) that the coating weight gauges' shutter mechanisms were malfunctioning. The gauges are Metso Automation Model 300 NDS gauges (serial numbers 9048LA, 9049LA, 9398LA, 9688LA) containing 2 Ci of Am-241 each. The shutters would not close when a user attempted to utilize the human-machine interface (HMI) and click `close shutter'. The maintenance department arrived approximately 30 minutes later. The air system was then placed in the closed position, ceasing air pressure to the devices. Upon the air being suspended, the shutters immediately closed on the devices. This indicated the issue was not with the shutter mechanisms. Both a solenoid and valve were replaced in a timely fashion; this returned proper functionality to the shutters. At no point were any individuals exposed to the primary beam of the devices.

"Before the July 1, 2026, incident, the shutters were last checked on June 2, 2026, and were functioning properly at that time.

"In addition, Global Gauge Corporation has been notified and is scheduled to service the devices and assess if there is a programming issue. The Department will perform a reactive inspection. More information will be provided as received."

PA event number: PA260014

AGREEMENT STATE REPORT - DOSE TO NURSING CHILD

The following information was provided by the Colorado Department of Public Health and Environment via email:

"A 33-year-old female patient, with an approximately 6-month-old nursing child, received a diagnostic nuclear medicine study. The patient was administered 300 microcuries of I-123 on the morning of August 3, 2026. The licensee neglected to confirm the patient's breastfeeding status or provide instructions on cessation of breastfeeding. The patient was released following the procedure, and no instructions regarding temporary or permanent cessation of breastfeeding were communicated. The licensee became aware of the error and was informed of the patient's breastfeeding status on the morning of August 6, 2026, because the patient called the radiation oncology and nuclear medicine department with questions. No immediate harm has been reported involving the patient or the nursing child. Initial dose estimates provided by the licensee indicate less than 5 rem total effective dose equivalent received by the nursing child, but the licensee is still determining if there is unintended permanent functional damage to an organ, as determined by a physician."

AGREEMENT STATE REPORT - FOUND SOURCE

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

"On July 25, 2026, the Agency conducted a radioactive source recovery operation and found an orphan source that was buried in the ground in Midland, Texas. The source is a 3M 6576 sealed source containing 100 millicurie (original activity date, April 1967) of cesium-137. The source was found in an unshielded condition and had no serial number. The Agency's investigations regarding the origin of the source could not determine the owner of the source. The discovery of the buried source was made on July 24, 2026, when a Texas Department of Public Safety nuclear detection unit officer on patrol along a county road detected elevated radiation levels with his vehicle on board radiation system while passing over a bridge. The officer stopped at the location and conducted a radiation survey which determined the presence of a cesium-137 source. The officer notified the Agency which then dispatched a health physicist to the site who confirmed these findings. It was determined that the radiation was localized at an area 8 feet below the road level and about 20 feet away from the bridge. The health physicist conducted contamination surveys at the location and found no removable contamination. The following morning, the source was recovered, placed in a shielded container, and transported to the Agency's sealed source storage facility. No individuals received a radiation dose in excess of the applicable dose limits during source recovery. Arrangements for the safe disposal of the source have been made by the Agency. This event was first reported by the Agency to the NRC Headquarters Operations Center on July 24, 2026, and updated on July 25 and August 7, 2026.

"Additional information will be made available in accordance with SA-300 reporting requirements."

Texas incident number: I-10312
NMED report number: TX260027

EN Revision Imported Date: 8/17/2026

EN Revision Text: MANUAL REACTOR TRIP

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

"At 0947 EDT on August 13, 2026, with Unit 1 in mode 1 at 100 percent power, the reactor was manually tripped due to 3 control rods dropping into the core. The trip was uncomplicated with all systems responding normally post-trip. Operations stabilized the plant in mode 3 [hot standby]. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves and main feedwater. Unit 2 was not affected.

"This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B).

"The NRC Resident Inspector has been notified."

PART 21 - NON COMPLIANT ELECTROMECHANICAL RELAYS

The following is a summary of information was provided by ABB Inc. via email:

On July 17, 2026, during calibration of a KF relay, ABB identified a deviation from the specified coil-assembly drying process. The affected coil assembly had completed the required air-drying stage, however, the subsequent force-drying (baking) stage had not been performed. The applicable process specifications required dipped transformers and coil assemblies to undergo a defined air-drying period followed by the specified force-drying (baking) cycle. After a review of production records, ABB identified 60 relays potentially manufactured under this condition and supplied to 12 customers. The affected population includes multiple class 1E electromechanical relay styles. Engineering testing of representative assemblies manufactured under the evaluated process conditions demonstrated compliance with the applicable 2.2 kV hi-pot acceptance criteria, and no immediate dielectric failure conditions were attributable to omission of the force-drying step that was identified under the tested dry condition. As of the date of this notification, ABB has not received any in-service failure reports from customers associated with the affected relays that are attributable to this deviation.

Affected Customers:
Catawba Nuclear Station
Oconee Nuclear Station
Georgia Power
Entergy Louisiana LLC
PSEG Nuclear LLC
Exelon Business Services
Westinghouse Electric
Duke Energy Carolinas
Dominion Energy Virginia
Constellation Energy Generation
Nextera Energy Resources

Responsible ABB Inc. Representative:
Percy Isaac
Plant Manager
ABB Inc.
2300 Mechanicsville RD
Florence, SC 29501
843-413-4700

AGREEMENT STATE REPORT - LOST EXIT SIGNS

The following information was provided by the Colorado Department of Public Health and Environment via email:

Eight tritium exit signs were declared lost by the licensee on July 16, 2026. The exit signs are Isolite Corporation model SLXTU1RW10, containing 7.09 Ci of tritium each.

Colorado Event Number: CO260017

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 - LOST EXIT SIGNS

The following information was provided by the Colorado Department of Public Health and Environment via email:

Four tritium exit signs were declared lost by the licensee on June 30, 2026. The exit signs are Safety Light Corporation model 2040, containing 9.25 Ci of tritium each.

Colorado Event Number: CO260018

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

EN Revision Imported Date: 8/17/2026

EN Revision Text: UNSUAL EVENT - CONTAINMENT FIRE ALARM

The following information was provided by the licensee via phone:

On 08/15/2026, at 1258 MST, Palo Verde Unit 3 declared an Unusual Event (HU4.2) due to receipt of a single fire alarm in containment that was not verified within 30 minutes. Unit 3 is stable at 100 percent power. Units 1 and 2 were unaffected and remain at 100 percent power. The cause of the alarm is under investigation.

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 08/15/2026 AT 1755 EDT FROM JUSTIN SUTTLE TO KAREN COTTON * * *

The following information was provided by the licensee via phone:

The licensee entered containment and reported that there were no indications of smoke or fire.

* * * UPDATE ON 08/15/2026 AT 1856 EDT FROM JUSTIN SUTTLE TO KAREN COTTON * * *

The following information was provided by the licensee via phone:

On 08/15/2026, at 1548 MST, Unit 3 terminated the Unusual Event. There was no smoke or fire in containment. The NRC Resident Inspector has been notified.

Notified CNRI EO (Walker), IRMOC (Grant), R4 BC (Dixon), DHS SWO, FEMA Operations Center, FEMA NWC, CISA Central Watch Officer, CWMD Watch Desk, DHS Nuclear SSA (email), DHS NRCC THD Desk (email).