Radioactive waste solidification device

A stirrer is disposed in a kneading vessel to which a solidifying material and water are supplied as starting materials for a paste. A baffle plate is situated vertically to a side wall in the kneading vessel, and formed at one place in circumferential direction of the kneading vessel. The baffle plate is situated above stirring blades so as not to abut against the rotating stirring blades. A discharge pipe for supplying the paste formed in the kneading vessel to a solidifying vessel is connected to the bottom of the kneading vessel. A washing water supply pipe having a pump and a valve is connected between the washing water tank and the kneading vessel. Since the baffle plate is disposed in the kneading vessel, washing performance for the rotating shaft of the stirrer can be improved by a simple constitution. (I.S.)