Preliminary analysis on radionuclides transport in the unsaturated environment

The assessment of the Wolsong LILW Disposal Center (WLDC) as a repository of radioactive wastes critically depends on the performance of the engineered containment system, and the natural, geologic system underlying the repository. The inventory of radionuclides, their mobilization and release from the repository, and their transport through the unsaturated zone (UZ) to the groundwater table and eventually to the biosphere are key factors and processes affecting the long-term performance of the system. This study is performed using TOUGH2 code for multiphase flow and transport simulator. In this modeling the amount of groundwater penetrating into the ground is important. The most important factors determining the unsaturated environment are the infiltration rate and medium permeability. For accurate modeling, validity of physical properties is required. As a further detailed model to develop, it is essential to calculate the source term and condition in and around the repository. Such a model may either implement some conservative scenarios and assumptions about containment breaching and waste mobilization