Diffusion of radionuclides in clay-based ceramics

The diffusion coefficients of sodium-22, strontium-90, and cesium-134 in clay-containing ceramics of three types are determined by the method of integral residual activity. It is found that at the investigated temperatures the diffusion coefficients of the radionuclides decrease in the order sodium-22, cesium-134, strontium-90. Migration of cesium-134 in comparison with sodium-22 is characterized by substantially lower values of the preexponential factor and diffusion activation energy. It is shown that in the case of ceramic made up of 89% by mass cambrian clay and 11% by mass perlite, increase in relative moisture content of the samples from0.05 to 0.3% leads to substantial (by 2-3 orders of magnitude) growth of the diffusion coefficients of the radionuclides. Further increase in the relative moisture content has practically no effect on their diffusive mobility