DIFFUSION COEFFICIENTS OF CRITICAL RADIONUCLIDES FROM RADIOACTIVE WASTE IN GEOLOGICAL MEDIUM

Diffusion (Ds) and distribution coefficients (Kd) are crucial for assessing the migration of radionuclides through geological media intended for the disposal of low and intermediate level radioactive waste. This study investigates the geological medium and groundwater characteristics relevant to the experimental determination of Ds and Kd. Samples were collected from the drilling conducted at the Saligny site, a candidate for waste disposal. The research emphasizes the necessity of characterizing the physical, chemical, hydrological, geochemical properties, and radionuclide migration behaviors at the selected site as vital input for safety assessments. Results indicated that the distribution coefficient values for Cs-137 in loess layers are significantly lower than those in clay layers, while for Co-60, the values remain consistent across soil types. Notably, diffusion coefficients for Cs-137 and Co-60 were found to be notably higher in loess compared to clay layers. The findings suggest that clay formations demonstrate effective sorption capabilities, potentially serving as a natural barrier to radionuclide migration from disposal facilities. Consequently, these results align well with existing literature for comparable soil types and concentration ranges.