Development of radionuclide diffusion model in clay-sand mixed media using random walk simulation

Yotsuji, Kenji*; Tachi, Yukio  ; Mitsuyama, Kazuaki*

In the geological disposal of radioactive wastes, clay-sand mixed media play a key role in the barrier system, and a quantitative understanding of the radionuclide diffusion behavior in these media is important for safety assessment. In this paper, structural models of clay-sand mixed media were developed, and radionuclides were randomly walked in the structural models to simulate radionuclide migration. At that time, the volume fraction of sand was systematically changed, and then the critical behavior of the structural factors of the medium was evaluated.