Isolation of radioactive waste in subterranean salt domes - where waste is placed in final store and then surrounded by concrete mixt. contg. bentonite swelling in presence of water

摘要

Medium- and/or weakly-radioactive waste is made into blocks or granulates, or compressed and encapsulated in sealed, transportable containers. The waste is then placed in a final storage zone formed by a cavity in the subterranean salt dome. A mixt. (a) is made of water and bentonite in ratio 10:1 to 4:1, the water being natural and free from synthetic radionuclides, but may contain tritium. Cement or cement and sand are then added to mixt. (a) using a min. ratio cement: (a) of 1:5 to obtain a mortar or cement milk. The cement milk has a water:cement ratio of 1-4, and is poured into the spaces between the blocks or cans of waste in the final store and allowed to harden to make a monolithic block. The result is increased safety w.r.t. unpredictable tectonic movements or earthquakes which might otherwise cause cracks or water penetration into the store.