Abstract: An aqueous solution containing granular ion exchange resin and filter aid as a radioactive waste generated from a nuclear power plant is supplied to the casing of a centrifugal film dryer, which comprises a casing, a rotating shaft inserted in the casing, rotating blades fixed to the rotating shaft within the casing, and a heating means for heating the wall surface of the casing. The aqueous solution flows down along the heated inside wall of the casing while the rotating shaft is rotated. Water of the aqueous solution is evaporated, while the granular ion exchange resin and the filter aid are turned into powder by the action of rotating blades in rotation. The powder is led to a pelletizer, and shaped into pellets. The pellets are filled in a drum, and asphalt is then filled in the drum. After the solidification of the asphalt, the drum is tightly sealed.