Experimental and numerical investigations of (TcO4)-Tc-99 (-) diffusion in compacted SPV 200 bentonite

摘要

Diffusion characteristics in bentonite are essential to quantify the transport of radionuclides through buffer/backfill materials in waste repositories. This study employs through-diffusion techniques to investigate the diffusion behavior of (TcO4)-Tc-99 (-) through SPV bentonite with various densities. The apparent diffusion coefficients for bentonite densities are estimated using Marquardt-Levenberg optimization algorithm in the HYDRUS-1D model. Based on the experimental and calculation results, Tc-99 could be considered as non-sorbing radionuclides. The data obtained in this study provide a valuable reference for the safety assessment of waste repositories.