The following information is a summary provided by the Nevada Department of Health and Human Services (the Department) via phone and email:
On May 6, 2025, the licensee reported to the Department a stuck open shutter on a Berthold LB 7440 gauge (150 mCi Cs-137, serial number 794). The fixed gauge remains installed pending the arrival of a contractor to replace the failed shutter.
Area surveys at 1 foot were 0.2 mR/hr. The gauge is in the wet mill and has little, if any, foot traffic by it. Due to the location and survey results being unchanged from normal operation, there is no additional exposure expected to the mine or mill staff until the gauge can be repaired by the contractor. The ladder to the gauge has been blocked and the walkway has been cordoned off.
This is the third occurrence in less than a year (6/18/2024, 7/8/2024, 5/6/2025) of the same model with the shutter being stuck in the open position. The licensee was reminded to report the failure to the manufacturer in accordance with the operations and maintenance manual for the gauge.
Nevada Item Number: NV250004