Development of bituminization process for radioactive wastes test by bench-scale plant

The bituminization of radioactive wastes from a fuel reprocessing plant has been made with a thin film evaporator in bench-scale test. Sodium nitrate solution without radioactivity was used for simulated evaporator concentrate, and mixed with distillation bitumen. The process has been proved to be generally successful. In the thin film evaporator, bitumen-waste mixture is laid uniformly on the heated surface by the blades of a rotor, and water evaporates off from the mixture. Circulation of thermofluid is used to heat throughout the system. Since the residence time of the mixture in the evaporator is short, the physical properties of bitumen are not affected. (Mori, K.)