Event Notification Report for May 11, 2026

EN Revision Imported Date: 5/11/2026

EN Revision Text: TROXLER MOISTURE DENSITY GAUGE INADVERTENTLY BUMPED BY TRUCK

The following summary information was provided by the licensee via telephone:

On 7/31/2023 at about 0730 MDT, employees of the City of Great Falls were standardizing a Troxler moisture density gauge (contained 9 millicuries of cesium-137 and 44 millicuries of americium-241) with the gauge on an asphalt lot and the source in its cage; as per standard practice. A loader truck inadvertently hit the gauge but was halted before it ran over the gauge. Some plastic on the gauge was damaged. The licensee halted operations and restricted access. Subsequently, radiation levels of 0.294 millirem per hour at 1 foot and 0.004 millirem per hour at 4 feet were measured, which were essentially background levels. No overexposure or other personnel injury were reported.

* * * RETRACTION ON 05/08/2026 AT 1319 EDT FROM MATT TRAUD TO ERNEST WEST * * *

The following is a summary of information that was provided by the licensee via telephone:

Both sources in the Troxler moisture density gauge remained intact and fully shielded following the collision with the loader truck. Therefore, this was a non-reportable event and this event is being retracted by the licensee. Additionally, the gauge was disposed of in accordance with NRC regulatory issue summary 2005-06.

Notified R4DO (Agrawal) and NMSS Events Notification (Email).

TECHNICAL SPECIFICATION DEVIATION

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

"On Thursday, May 7, 2026, University of Utah Training Reactor (UUTR) staff identified that the reactor console and all associated nuclear instrumentation, including the scram logic drawer was powered by an uninterruptible power supply (UPS). Therefore, a loss of building electrical power would not immediately result in a reactor scram. Instead, the reactor would not scram until the UPS deenergized. This aspect contradicts the basis for the console power supply safety channel function of scram on loss of electrical power (Technical Specification 3.2.3 Reactor Safety System). The basis for the console power supply states, `If the reactor console loses electrical power, the reactor will be scrammed even if the UPS is installed.' "


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

The reactor was shut down at the time this condition was discovered. The licensee intends to maintain the reactor shutdown until this condition is corrected and a formal 14-day written report has been submitted to the NRC.

LOSS OF THE PUBLIC PROMPT NOTIFICATION SYSTEM

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

"On May 9, 2026, at 1529 CDT, the National Weather Service reported to Cooper Nuclear Station that the National Warning System radio tower near Shubert, Nebraska was not functioning. The Shubert tower transmitter activates the emergency alert system and tone alert radios used for public notification. Additional information from the National Weather Service received at 1244 CDT on May 10, 2026, determined that the Shubert Tower transmitter would not likely be repaired within 24 hours. The backup notification system has been verified as available.

"This condition is reportable under 10 CFR 50.72(b)(3)(xiii) as a major loss of the public prompt notification system capability since the backup alert methods do not meet the primary system's design objective. The NRC Senior Resident Inspector has been informed."