DEVELOPMENT OF MATRICES FOR VITRIFICATION OF STRONTIUM AND CESIUM CONCENTRATE FROM HIGH-LEVEL WASTE

Studies of borosilicate glasses containing 4.7 and 2.3 wt % of cesium and strontium oxides, respectively, were carried out. Homogeneous chem ically resistant glasses were obtained with compositions (wt %): sodiu m oxide 10-20, boron oxide 10-17, silicon oxide 45-50, aluminum oxide 2-5, and the sum of barium, lead, and titanium oxides 4-6. The tempera ture of preparation of such glasses was no higher than 1150 degrees C. The rate of leaching of principal components (sodium, silicon, and bo ron) from the glasses into distilled water in the temperature interval from 20 to 130 degrees C ranges from 10(-6) to 10(-4) g cm(-2) day(-1 ). The corrosion of the glasses occurs through the mechanism of congru ent dissolution. The calculated activation energy for leaching of sili con was 48 kJ mol(-1) and the diffusion coefficients of sodium and ces ium were of the order of magnitude of 10(-12) and 10(-16) cm(2) s(-1), respectively. Thus, the glass matrix with the suggested composition e xhibits a high water resistance over a wide temperature interval.