Abstract: A substance such as radioactive liquid waste is heat treated using microwave by introducing the substance into a vessel made of a material reflective to microwave and containing spherical bodies made mainly of a material transmissive (i.e. transparent) to microwave. Microwave is applied to the substance while imparting movement to the spherical bodies. The substance is heat treated while in contact with the spherical bodies and is separated from the spherical bodies and pulverized by the friction and collision between the moving spherical bodies. An apparatus for carrying out the method is described.

Abstract: An improved device for effectively removing radioactive particles in moist gas has a pipe for feeding therethrough a moist gas containing radioactive solid particles, a solid-gas separation filter disposed in the pipe, a microwave generator and a wave guide connected between the pipe and the generator. Within the wave guide there is disposed a shielding plate capable of passing the microwave therethrough and preventing the spreading of contamination. Microwave from the generator is applied to the filter by means of the wave guide, and moisture condensate and the like on the filter is heated and evaporated by the microwave to minimize clogging of the filter.