Abstract
This study attempts to investigate that sorption and diffusion behaviors of Se and Cs on mudstone for safety assessment of underground radiowaste repository. In order to understand the sorption and diffusion behaviors on mudstones, experiments including solid analysis, batch tests, kinetic sorption/desorption test and column diffusion test. Solid analysis shows that major mineral compositions and other properties of mudstone. From batch tests,it is observed that differences of Kd values between anaerobic condition and aerobic condition regardless of GW or SW. Based on the results, Freundlich and Langmuir isotherm models have been determined the radionuclides concerntration ratio of liquid and solid. From most kinetic sorption/desorption tests, Cs reacts equilibrium imediately; Se sorps onto mudstone slowly and reaches equilibrium during 14-days experiment. In the column diffusion tests, exact analytical solutions have been used in lieu of the method suggested by Crank (1975), to find the apparent diffusion coefficient (Da). Results of diffusion tests show higher retardation factors in groundwaterand also show a beter retardation effect in Se solutions.