Bituminization of low- and intermediate-level radioactive concentrates

The results and experiences are summed up from the research and development of the technology of bituminization of low- and intermediate-level radioactive concentrates generated in the operation of nuclear power plants with WWER-440 reactors. The experiments took place on a pilot plant bituminization line with various model solutions at an evaporator capacity of 70, 100 and 140 litres per hour. The composition of the solutions changed in dependence on the knowledge of the composition of actual concentrates in the V-1 nuclear power plant at Jaslovske Bohunice. The following factors were studied in the concentrate: the effect of its pH, its borate content and content of metal carbonates, the content of organic acid salts, the content of detergents, etc., on the process of bituminization. Physico-chemical conditions are described under which the operation of the evaporator was fail-safe and filling of the bituminization product with salts homogeneous. A low water content of up to 1% was achieved. The properties of the bituminization product were negatively affected by a high level of heavy metal oxides, surfactants, oxalates and citrates. In order to improve the properties of the product it will be necessary to replace bitumen emulsion Silembit-60 used as reinforcement matrix, by a different type of bitumen. (Z.M.)