Page:4SIGHT manual- a computer program for modelling degradation of underground low level waste concrete vaults (IA 4sightmanualcomp5612snyd).pdf/57

 Figure 2: Formation factor, $$D/D^f$$, due to hydration (circles) and to leaching (squares) for w/c=0.35 (after [14]). The solid line represents the approximation used by for the leaching formation factor.

THe relative change in permeability can be calculated using $$\xi$$. The Katz-Thompson equation relates permeability to $$\vartheta$$ [15]: Rh where $$d_c$$ is the diameter of the largest sphere which can pass through the pore space of the sample. Also, given that $$d_{c}\propto\vartheta$$ [16], the relative change in permeability becomes Rh The final dimensionless advection-diffusion equation is a combination of eqns. 14, 31, and 33: Rh There is one such equation for chemical species $$i$$.

The flow of the program is summarized by the pseudo-code program shown in Figure 3. The program naturally divides itself into three parts: initialization, ion propagation, and final state output.