Study and development of incinerator ash immobilization by hydrothermal solidification

One method of solidifying inorganic radioactive waste, such as incinerator ash, is the hydrothermal solidification method. The advantage of this method is that the conditions of solidification are comparatively mild, compared with an ordinary hot pressure sintering, and that solidified bodies similar to ceramics can easily be obtained in a closed system. In the past, several studies on this method were conducted using non-radioactive simulated waste. Evaluation of leachability, the degree of contamination of an autoclave used, and also establishment of the handling technique for radioactive incinerator ashes as well as their solidified bodies are now urgently desired. In this study, leaching experiments were carried out by the use of an industrial incinerator ash impregnated with /sup 137/Cs and /sup 60/Co as tracers and a radioactive incinerator ash generated from a nuclear facility. In addition, an engineering scale test plant was built to obtain the necessary engineering data for full scale plants