Immobilizations of strontium and cesium using hydrous titanium oxide and zeolite

Heat generating nuclides, such as 90Sr and 137Cs, are contained in the high-level waste arising from nuclear fuel reprocessing. In the partitioning process developed in our laboratory, these nuclides are separated using the column packed with hydrous titanium oxide and zeolite. The present paper deals with the immobilizations of strontium and cesium adsorbed on these inorganic exchangers by calcination. The formation of strontium titanate proceeded over 1000 degC in the calculation of the orthotitanic acid loaded with strontium and the vitrification proceeded in the calcination on the natural mordenite loaded with cesium. The leaching rates of strontium and cesium for the samples calcined at 1000 degC were two orders of magnitudes lower than those for the high-level waste vitrified as borosilicate glass. (Auth.)