Decommissioning of a Caesium-137 Sealed Source Production Facility

Amersham owns a former Caesium-137 sealed source production facility. They commissioned RWE NUKEM to carry out an Option Study to determine a strategy for the management of this facility and then the subsequent decommissioning of it. The decommissioning was carried out in two sequential phases. Firstly robotic decommissioning followed by a phase of manual decommissioning. This paper describes the remote equipment designed built and operated, the robotic and manual decommissioning operations performed, the Safety Management arrangements and summarizes the lessons learned. Using the equipment described the facility was dismantled and decontaminated robotically. Some 2300kg of Intermediate Level Waste containing in the order of 4000Ci were removed robotically from the facility. Ambient dose rates were reduced from 100's of R per hour {gamma} to 100's of mR per hour {gamma}. The Telerobotic System was then removed to allow man access to complete the decommissioning. Manual decommissioning reduced ambient dose rates further to less than 1mR per hour {gamma} and loose contamination levels to less than 0.25Bq/cm2. This allowed access to the facility without respiratory protection.