Application of Zeolite for the Treatment of Radioactive Waste

Abstract

Zeolite was used to various investigation on the application to atomic energy chemistry such as processing of radioactive wastes.
For the fixation of ⁸⁵ Kr, zeolite encapsulation method and chemical fixation method has given favorable results concerning ⁸⁵ Kr loading, but it would be necessary for its practical use to reduce the pressure on encapsulation.
For the fixation of radioactive nuclides into zeolites from radioactive waste solution, various investigations were performed in many countries. The treatment of large volume of the radioactive waste solution in the Three Mile Iseland atomic power station have been investigated with mixed zeolite of chabazite and zeolite A.
Various zeolites were also studied on the application to the solidification of ¹³⁷ Cs and ⁹⁰ Sr in high level liquid waste by present author. This study was given many favorable results. Cs saturated zeolite A, X and Y were transformed to the mixture of nepheline and pollucite above 1000°C, and mordenite saturated with Cs was also transformed to CsAlSi₅0₁₂ at 1200°C. These cesium aluminosilicates were very stable. Leaching rates of Cs from the calcined zeolites were decreased with increasing in calcination temperature, and the leaching rate of Cs from zeolites calcined at 1200°C were less than 10^-9g/cm². day which are lower 3 orders than the leaching rate of Cs from boro silicate glass. The volatilization of Cs from zeolite during calcination at high temperature was very little.