The possible mass loss or the physical stability of the
compacted bentonite block by an erosion of the
bentonite particles was approximated in this study. It
is assumed that the buffer lies in a cylindrical hole of a
known radius r (2.7 cm) and height h (10 cm), that 10%
of the exposed rock consists of a fractured pore space
into which bentonite particles may escape, and that the
diffusion rate D of the bentonite particles is around