[2A13-16] Nuclide Migration 1

[2A13] Diffusion of Cs, I, and HDO in a Pre-Neogene Sedimentary Rock

*Linyi Hou¹, Kanako Toda¹, Yuta Fukatsu², Takamitsu Ishidera², Takumi Saito¹ (1. UTokyo, 2. JAEA)

Keywords:deep geological disposal, host rock, pre-Neogene sedimentary rock, diffusion

To investigate the barrier performance of a pre-Neogene sedimentary rock for deep geological disposal of high-level radioactive waste (HLW), the heterogeneity of the rock matrices and the diffusion behaviors of cesium, iodine, and HDO were examined. The structures of the rock samples examined by X-ray Computed Tomography (X-ray CT) are used to interpret the diffusion behaviors of the ions and HDO. The research reveals that the rock's heterogeneity significantly influences radionuclide diffusion, challenging traditional models and underscoring the need for advanced modeling.