Event Notification Report for July 30, 2025

AGREEMENT STATE REPORT - CONTAMINATION EVENT

The following report was received by the North Carolina Division of Radiation Protection via email:

"On May 8, 2025, the licensee reported that a source [Am-241/Be, CPN23, 50mCi] was ruptured during a source recovery task. The source was being removed from a nuclear gauge down hole probe. Once the source was removed from the probe, it was immediately leak tested. Two leak tests were performed and both readings pegged at full scale on the licensee's GM Pancake Survey Meter. The area was immediately cleared and one individual (the person conducting the source removal) was found to have contamination on their hands at 6000 CPM and 3500 CPM on portions of their clothes. This person was immediately decontaminated and a follow-up urine bioassay revealed less than minimum detectable levels. No other employees were contaminated, and the source was secured, awaiting disposal via a radioactive waste broker. Additional surveys of the work area revealed areas that required decontamination. The area was secured from entry and is awaiting decontamination by an outside vendor."

North Carolina Event Number: 250009

AGREEMENT STATE REPORT - RECOVERED SOURCES

The following report was received by the Georgia Radioactive Materials Program via email:

"On March 27, 2025, two sources (Ge-68) were found at a car repossession lot. It was determined the sources had been at that car repossession lot since sometime in October of 2024 and remained there until March 27, 2025, at which time GFD Hazmat recovered them and handed them off to EPD. The original activity was 1.49 mCi per source. The estimated decayed value was 0.05 mCi at the time of discovery and 0.04 mCi to date. The manufacturer confirmed the shipping location (GA 1490-1) and date of the source with a serial number.

"The licensee responded with disposal records to Sanders Medical (Tennessee licensed facility). Sanders was able to confirm receipt of the material on April 15, 2025. It was determined the serial numbers listed on the lead pigs did not match the serial number of the enclosed sources.

"On April 15, 2025, GA 2047-1 (Training Facility) gained possession of the found sources. The manufacturer (EZ) confirmed the same shipment location and licensee with the accurate serial numbers. After several attempts to reach out to Sanders, for confirmation of receipt, the State of Georgia could not get a response until July 15, 2025. At that time, a staff member from Sanders confirmed they did not receive, nor have they ever received the two sources.

"The licensee was unable to provide disposal records for the sources, although routinely uses Sanders for disposal services. The licensee received a notice of violation on July 23, 2025."

Georgia Incident Number: 102

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

BOTH TRAINS OF CONTROL ROOM AIR CONDITIONING INOPERABLE

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

At 2324 CDT, on July 28, 2025, control room air conditioning (CRAC) 'B' tripped at Grand Gulf Nuclear Station (GGNS) approximately 5 minutes after loading the compressor by adjusting the thermostat [down] per standby service water quarterly surveillance instructions. CRAC 'A' was manually started at 2326 CDT and at 2329 CDT it subsequently tripped. After investigating the compressors and breakers per the alarm response instructions with no abnormal indications, CRAC 'B' was restarted and tripped again. Cooling water was rotated from plant service water to standby service water and CRAC 'A' was successfully restarted at 2358 CDT and remains in service.

While both control room air conditioning subsystems were inoperable GGNS entered technical specification limiting condition of operation (LCO) 3.7.4 condition 'B', actions requiring verification of control room temperatures less than 90 degrees F and restoring one subsystem to operable status in 7 days. Control room temperatures reached 79 degrees F, maximum, before CRAC 'A' was restarted. GGNS has exited condition 'B' in LCO 3.7.4 and entered condition 'A' to restore CRAC 'B' in 30 days.

This event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition which could have prevented the fulfillment of a safety function.

The NRC Senior Resident Inspector has been notified.

MANUAL REACTOR SCRAM

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

At 2058 CDT on 7/28/2025, a spurious trip of the reactor building exhaust ventilation [system] caused a subsequent trip of the reactor building supply ventilation [system]. This ventilation system failure resulted in the degradation of reactor building differential pressure and at 2200 CDT the differential pressure exceeded the technical specification limit, resulting in the inoperability of Secondary Containment. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72 (b)(3)(v).

Failure of the ventilation system also resulted in elevated temperatures in the steam chase area of the plant. Operators reduced power to slow the temperature rise, however, at 2324 CDT on 7/28/2025 with Unit 1 in mode 1 at 41 percent power, the reactor was manually scrammed due to steam chase temperatures reaching the procedural limit. The scram was not complex, with all systems responding normally post-scram. Reactor water level is being maintained via the feedwater system. Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. This condition is being reported as a four-hour, non-emergency notification per 10 CFR 50.72 (b)(2)(iv)(B). There has been no impact to the health and safety of the public or plant personnel.

The NRC Resident Inspector has been notified.

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

Steam chase temperature has begun to lower, and the licensee intends to cooldown to mode 4 for maintenance.

FITNESS FOR DUTY EVENT

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

"On July 28, 2025, Watts Bar Nuclear (WBN) operations was informed that a WBN licensed reactor operator had tested positive for a controlled substance, in violation of the Tennessee Valley Authority (TVA) fitness for duty policy. A random screening was completed on July 17, 2025. The results were sent to the TVA medical review officer on July 28, 2025. The test was declared positive for a controlled substance and WBN operations was notified at 1333 EDT on July 28, 2025. The individual's unescorted access has been revoked."

The NRC Resident Inspector has been notified.

PART 21 - THERMAL OVERLOAD OF VOLTAGE REGULATORS

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

"This is an initial report notification pursuant to 10 CFR Part 21.21.

"Cook Nuclear Plant completed an internal evaluation concerning an issue with an emergency diesel generator (EDG) voltage regulator (VR) supplied by Paragon Energy Solutions, LLC. An issue was identified during a surveillance test conducted on April 22, 2025, concerning a thermal overload (TOL) for the VR which spuriously trips causing a condition where the EDG VR can no longer control the generator voltage, resulting in the inability of the EDG to supply automatic onsite emergency AC power. A failure analysis was completed on June 6, 2025, determined that the cause of the spurious trips is associated with a heater dimensional tolerance deficiency lowering the activation threshold of the TOL bimetallic strip and a workmanship deficiency associated with a braided control wire restricting the movement of the TOL pressure bar. Extent of condition examinations were performed and one additional TOL was found to be impacted. The two impacted TOLs have been replaced. A written notification will be provided within 30 days."

Affected Plants: Cook Nuclear Power Plant.

The NRC Resident has been notified.