Abstract: A method of processing radioactive waste resin by pyrolyzing radioactive waste ion exchange resin generated in a nuclear plant such as a nuclear power station. First, the ion exchange resin is pyrolyzed at a low temperature, and the resulting decomposition gas is separated. Second, the ion exchange resin at a high temperature, and the resulting decomposition gas is separated. Finally, the residue of the ion exchange resin is hot-pressed into a molded article.

Abstract: YThis invention concerns solidification products capable of immobilizing radioactive wastes containing water soluble solid components stably for a long period of time, as well as a process for producing the same, in which radioactive wastes are immobilized with an alkaline earth metal silicate compound and the alkaline earth metal silicate compound intakes the water content in the solidifying agent as the bound water to or a hydrate. High temperature and high humidity condition has been found to be necessary upon curing in order to take the water content as the bound water. This invention can provide solidified wastes with less development of detects such as open pores or cracks.

Abstract: The invention is concerned with radioactive waste pellets in solidified form in which radioactive waste pellets including light waste pellets having specific gravities smaller than that of a filler are solidified with the filler in a container. A cover disposed in an opening portion of the container is provided with filler injection ports which do not permit the passage of the light waste pellets. The invention is further related to a process for forming radioactive waste pellets in solidified form by injecting the filler through the filler injection ports formed in the cover, so that the radioactive waste pellets and the filler are uniformly solidified.

Abstract: In a method of processing radioactive spent ion exchange resin, the spent ion exchange resin is pyrolyzed in an inert atmosphere and harmful decomposition gas such as sulfur and nitrogen compounds generated during pyrolysis is separated. Next, the spent ion exchange resin is pyrolyzed in oxidizing atmosphere and harmless gases such as carbon dioxide and water vapor gases are separated. It is preferred that a transition metal as a catalyst be adsorbed through ion exchange into spent cation exchange resin, and an anionic atom group containing a transition metal as a catalyst be adsorbed through ion exchange into spent anion exchange, before both of the pyrolysis steps. The pyrolysis is carried out at two atmosphere stages, and the harmful and harmless gases are decomposed separately. The pyrolysis in both of pyrolysis steps is effected at a temperature in the range of from 240.degree. to 420.degree. C.

Abstract: A process for solidifying a radioactive waste by using an alkali silicate composition prepared by using as silicate source amorphous reactive silica obtained from acid earth by acid treatment as solidifying agent can give a solidified body excellent in weather resistance for a long period of time and excellent in resistance to leaching of radioactive materials with a low cost.