Method of heating radioactive waste solidifying device

Purpose: To enhance the safety of a radioactive waste solidifying device by employing low pressure saturated steam as a main heating source of an evaporator for solidifying the liquidized aqueous radioactive waste with asphalt. Method: Liquid waste is supplied from a liquid waste tank to an evaporator, and preheated liquefied asphalt is supplied from an asphalt tank thereto. An agitating rotor is provided in the evaporator to agitate the liquid waste and the asphalt therein. A heater with low pressure saturated steam pressure is provided as a main heater upstream of the evaporator, and an electric heater is integrally provided as an auxiliary heater downstream thereof. The molten mixture of the liquid waste and the asphalt is heated by the low pressure saturated steam so that the residual water content becomes lower than approx. 10wt%, and is then heated by the auxiliary heater so that the discharged mixture temperature becomes higher than approx. 1400C. (Sekiya, K.)