Event Notification Report for June 11, 2025

LOST BRACHYTHERAPY SEED

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

"On May 30, 2025, the radiation safety officer (RSO) at HCA HealthONE Sky Ridge notified the Colorado Department of Public Health and Environment via phone call that a prostate brachytherapy seed containing 2.5 mCi of palladium-103 was discovered to be missing during the licensee's inventory. The inventory was conducted on May 7, 2025, but the actual date of loss is unknown."

Colorado Event Number: CO250015


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 Illinois Emergency Management Agency (the Agency) via phone and email:

"The Agency was contacted on 6/3/25 by the radiation safety officer for Hanson Professional Services, Inc. to report that a Troxler 3440 moisture density gauge (8 mCi Cs-137, 40 mCi Am-241/Be) had been damaged on a construction site in Pekin, IL. [The licensee reported that] approximately a half-hour earlier, a truck backed over the gauge damaging the case and electronics. The source rod was not extended when the incident occurred. The licensee did not have a survey meter, but the gauge user had isolated the area and was maintaining direct surveillance of the device.

"Agency staff arrived to assess the gauge approximately 90 minutes later. Both sources were undamaged, and exposure rates were consistent with the sealed source and device registry sheet. The source rod was fully retracted, and the shutter closed. The transport case was not damaged and was used to package and prepare the gauge for return to the licensee's storage vault. Area surveys were taken, and the incident did not result in contamination, loss of radioactive material or exposures in excess of regulatory limits. That evening, the gauge was returned to the licensee's secure storage and will be leak tested prior to being shipped to the manufacturer for repair/disposal.

"Investigation findings indicate the gauge user walked away from the gauge momentarily when returning to their vehicle. A vehicle on the site then backed over the device, crushing the housing, but not damaging either source or its shielding. The root cause of the event is failure of the gauge user to maintain constant surveillance and prevent unauthorized access to licensed material. This report will be kept open pending receipt of the licensee's written report identifying corrective actions."

Illinois item number: IL250023

PART 21 - GATE VALVE STEM FAILURE

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

"On June 4, 2025, the Tennessee Valley Authority (TVA) determined there are manufacturing non-conformances associated with the stem failure on a 10-inch, Class 900 Anchor Darling double-disc gate valve, used as a high pressure coolant injection system (HPCI) isolation valve in Browns Ferry Nuclear Plant, Unit 3 (vendor drawing: W0025604; serial number: E125T-2-2).

"On May 9, 2024, the vendor, Flowserve, was contacted and assumed responsibility for performing the Part 21 Evaluation for this valve. On October 28, 2024, Flowserve provided a 10 CFR 21.21(b) notification to TVA, stating that they were not capable of evaluating the existence of a defect. TVA procured additional engineering expertise to complete the required evaluation. These evaluations were tracked by TVA under CR 1942523. An independent failure analysis by BWXT was provided to Flowserve. BWXT concluded that 'the most likely cause of failure was brittle overload fracture due to a combination of tensile and bending forces that were exacerbated by the presence of shallow outer diameter initiated cracks and a significant loss of material ductility due to thermal embrittlement.' TVA also procured a second independent technical evaluation from MPR Associates, Inc., and provided their report to Flowserve to help with their evaluation. This report concluded that the event was apparently caused by an improper upper wedge-to-stem joint, and the resulting mismatch in mating surface diameters resulted in the bending stress which led to the valve failure, in conjunction with thermal embrittlement and excessive torques. TVA is providing notification of the existence of the defect and its evaluation.

"This event was entered into the corrective action program as condition report 1914295.

"The NRC Resident Inspector has been notified of this event, and a written report will be submitted within 30 days. Previous interim reports regarding this issue were submitted on June 23, 2024; August 22, 2024; and
November 27, 2024."

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

The non-conforming part is no longer in service. There are similar parts in service at the Browns Ferry site, but it has been determined that the risk is low. Discussion will follow in the 30-day report.

FITNESS FOR DUTY

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

At 1230 EDT on June 10, 2025, a non-licensed supervisor failed a fitness for duty test. The NRC Resident Inspector has been notified.