Visualization and analysis of the tracer migration process in the crack by means of X-ray CT

Sato, Akira*; Arimizu, Takuto*; Yonemura, Hirotaka*; Sawada, Atsushi 

The advection and dispersion of contaminated materials in a rock mass are one of the important factors to evaluate the characteristics of the rock mass as a natural barrier function for a radioactive waste disposal project. In this study, X-ray CT method was applied to evaluate the advection and dispersion of solute in the crack which exists in rock mass. In order to visualize advection and dispersion phenomena, the tracer migration test have been conducted and tracer migration process was visualized by X-ray CT scanner. Here, an indicator, coefficient of tracer density increment, was newly introduced to analyze tracer migration. This is the indicator that represents the density of the tracer in the crack, and the evaluation of the density distribution of the tracer becomes possible. In this study, the influences of the crack aperture to the tracer migration process are discussed.