Event Notification Report for February 06, 2026

AGREEMENT STATE REPORT - MEDICAL EVENT

The following information was provided by California Department of Public Health, Radiologic Health Branch via email:

"On January 27, 2026, a patient treatment with Y-90 Theraspheres was conducted at the Loma Linda University Medical Center in which a therapeautic dose of 5.4 GBq (146 mCi) was prepared for administration to an individual. During the procedure, administration problems occurred and the dose to be administered was measured to be 25 percent of the prescribed measurement which had been determined.

"The remaining dosage and delivery system have been isolated in order to decay to the point where it can be sent back to the supplying vendor for investigation and assessment of reasons for the equipment failure. This is being reported to the NRC as a 10 CFR 35.3045 A, B, and C medical event due to the administered dose being less than 20 percent and less than 50 percent of the prescribed dosage."


California event number: 012826

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: 2/5/2026

EN Revision Text: EDG ACTUATION AND HPCS SYSTEM INOPERABLE

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

"On February 3, 2026, at 2338 CST, River Bend Station (RBS) was operating at 100 percent reactor power when the standby service water pump `C' (SWP-P2C) faulted, tripped, and locked out during the performance of a routine surveillance. The pump fault caused E22-ACB04, the normal division III 4.16 KV bus supply breaker, to trip and lock out. The division Ill emergency diesel generator (EDG) started as designed and powered the division III 4.16 KV bus. There are no signs of fire. The cause of the SWP-P2C fault is still under investigation.
"The trip of E22-ACB04 resulted in the inability to meet [surveillance requirement] SR 3.8.9.1 forcing entry into [limiting condition for operation] LCO 3.8.9 required action 'E.1' and declaring the [high-pressure core spray] HPCS system inoperable.
"This event is being reported under 10 CFR 50.72(b)(3)(iv)(A) as an event or condition that results in valid actuation of emergency AC electrical power systems and 10 CFR 50.72(b)(3)(v)(D) as an event or condition that at the time of discovery could have prevented the fulfillment of a safety function.

"The NRC Resident has been notified."

EN Revision Imported Date: 2/5/2026

EN Revision Text: PART 21 - INCORRECT TENSION SPRING USED FOR 600V BREAKERS

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.

"On January 26, 2026, Cook Nuclear Plant completed a Part 21 evaluation concerning an issue with the refurbishment kit used for K-Line series 600V Breakers supplied by ABB, Inc. An incorrect tension spring was supplied in one of the refurbishment kits. The refurbishment kits should be supplied with two tension springs: P/N 650216A00 and P/N 650216E00. The kit received was missing P/N 650216A00 and had two of P/N 650216E00. The incorrect 650216E00 spring could have been installed into a K-Line series 600V breaker in the location intended to accept the 650216A00 spring. The 650216E00 is a lighter spring and may not be capable of providing the tensioning force required to prevent an aged breaker from slow closing. A breaker's failure to charge and close properly could result in an arc fault condition. The breakers were inspected for the correct spring, which is visible from the front of the breaker between a gap in the mechanism cover and the charging handle. All breakers installed appear to have the correct springs installed.

"One spare breaker, not installed in the plant, appears to have had the incorrect spring installed. A written notification will be provided within 30 days."

Affected Plants: Cook Nuclear Power Plant.

The NRC Resident has been notified.

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

The wrong part numbers were identified in the refurbishment kits on December 1, 2025. A site engineer noted the wrong spring installed in a spare breaker as part of the Part 21 evaluation. Corrective actions included notifying the vendor and returning the unused refurbishment kits.

OFFSITE NOTIFICATION FOR ONSITE FATALITY

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

"At 1659 EST, offsite medical personnel [arrived on site and] declared a site employee deceased due to a non-work-related medical event inside the radiation control area. The individual was not contaminated. A notification to the Occupational Health and Safety Administration was made in accordance with regulatory requirements at 1852 EST. This is a four-hour non-emergency notification for notification of another government agency. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi).

"The NRC Resident Inspector has been notified."

AGREEMENT STATE REPORT - GAUGE SHUTTER INOPERABLE

The following is a summary of information provided by the North Dakota Department of Environmental Quality via phone and email:

The licensee reported difficulty opening the shutter on a fixed gauge during routine operating checks. The licensee is uncertain if the shutter could be successfully closed again. No visible damage to the gauge was noted. No overexposure to personnel was noted. The shutter was left in its normally open position.

Model: LB 7440-F-CR
Manufacturer: Berthold
Source: 115.9 mCi Cs-137

The vendor will be onsite February 4, 2026, to repair or replace the gauge.

AGREEMENT STATE REPORT - LOST SOURCES

The following is a summary of information provided by the New Mexico Environment Department via phone and email:

On January 12, 2026, the licensee, holder of a New Mexico academic broad scope 'A' license, reported that during a comprehensive physical inventory, conducted on August 8, 2025, for its license renewal application submittal, sixteen (16) discrete sources could not be located. The licensee's review of program records confirmed that the listed materials were not present in their last recorded locations, and no documentation exists indicating authorized transfer, disposal, or decay-in-storage for these items. The exact disposition of the materials is unknown. An exhaustive search of laboratories, storage rooms, and radioactive waste collection areas was conducted by the licensee. No additional radioactive materials were identified.

Based on historical program review by the licensee, plausible scenarios include improper disposal as non-radioactive waste, undocumented transfer, or continued onsite storage in an unidentified location, including the licensee's radioactive materials storage location, pending final disposal. The licensee attributed the loss to a systemic failure in inventory accountability that occurred over an extended period. The licensee's evaluation concluded that based on the isotopic properties, maximum quantities, and dosimetry review, it is highly improbable that any individual, either staff or public, received a dose exceeding limits.

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 - DAMAGED MOISTURE DENSITY GAUGE

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

"On January 30, 2026, RHB received notification that the licensee's portable nuclear gauge was damaged. During road construction in the city of Tracy, CA, a CPN MC3 (S/N 3604, 10 mCi Cs-137, 50 mCi Am-241/Be) was run over by a concrete truck. The gauge sustained damage to its housing structure and source rod, which snapped off. The gauge was not taking measurements and had its source rod in the shielded position at the time of the incident. No contamination is expected at this time. The licensee has contacted the manufacturer for disposal. RHB will investigate this matter further."

RHB 5010 number: 013026