Development of realistic nuclide migration model using reactive transport / particle tracking simulations for TRU waste geological repository

Koike, Ayaka*; Yoshida, Fumiko*; Mihara, Morihiro  

NUMO developed a near-field radionuclide migration model for assessing the safety of a deep geological repository (DGR) for TRU waste. Previous models conservatively represented the region inside the disposal tunnel structure as a high-permeability porous medium due to uncertainties regarding long-term cementitious material evolution. In this study, NUMO updated these models to represent the long-term evolution of cementitious materials filled within / between waste packages more realistically. This means that the importance of realistically evaluating the evolution of cementitious materials to demonstrate the confidence in the safety of DGR.