Radioactive waste may arise throughout the lifetime of any type of nuclear facility. This waste has to be isolated from the environment using the engineered and natural barriers of near surface or deep geological radioactive waste repository. Before final disposal, the waste volume is reduced in the treatment process and then it is immobilized into the stable matrix. In Slovakia, the treated radioactive waste is conditioned into fibre-reinforced concrete containers using a cementation technology. These containers are the only overpacks approved for near surface disposal in the National Radioactive Waste Repository located at Mochovce nuclearsite (Slovakia). Every filled container has to fulfill the defined limits and conditions for safe transport and disposal. The dose parameters, determining the safety of personnel handling a container, are one of them. Basically, the doses are measured on the container walls’ outer surfaces and on the lid of the container. The dose monitoring in 1 meter distance from the container walls and from the lid of the container is performed before transportation as well. The calculation code VISIPLAN 3D ALARA is a planning tool and it calculates dose parameters also for the above mentioned positions concerning the fibre-reinforced concrete container which contains waste with different physical or radiological characteristics. In the paper, calculated data are compared with in-situ measurements. Using VISIPLAN 3D ALARA planning tool, various scenarios are evaluated. Finally, the optimization leading to the lowest radiation exposure of personnel handling the filled fibre-reinforced containers is discussed.
A reliability engineering study for a near surface radioactive waste repository using genetic algorithm
