Monte Carlo computation of directional diffusion coefficients

In earlier work the net leakage from lattice cells was computed, from first principles, by Monte Carlo. On the other hand, this leakage was divided into axial and radial components by an ad hoc prescription. It has recently been found that this prescription leads, in some cases, to anomalous results. A more rigorous computation of leakage components is formulated. Calculations using the proposed method have been carried out for some typical GCFR lattice cells. These computations give an axial heterogeneity effect about twice as large as the radial effect, thus tending to substantiate a working hypothesis advanced earlier on the basis of simple physical arguments