Radiocolloid migration in backfill in semi-infinite cylindrical geometry

In the waste repository, backfill exists between a waste container and surrounding medium. Due to the strong filtration in the backfill, colloid concentrations decay out very rapidly along the space. Inside the backfill, diffusional transport of radio colloid is more dominant than that of advection. When the Peclet number is lower than 2 which means that the diffusion is dominant, CDM (central difference method) is well applied. In this paper two dimensional CDM scheme is developed for radial and angle direction in cylindrical geometry. Then mass fluxs at a given position inside the backfill are predicted. Even though our model can be expanded for the case with filtration coefficient distribution, in this paper, only the case with mono filtration coefficient is analyzed. (Author)