Multi-scale modeling of hydrogen isotope transport in porous graphite

We present a multi-scale model for hydrogen isotope transport in graphite. We use molecular dynamics (MD) simulations to study hydrogen isotope transport in a graphite micro-crystal which is a few nanometers in size. The MID results are parametrized in a Kinetic Monte Carlo (KMC) model as a diffusion process of two competing thermally activated events. Micro-crystal diffusion coupled with a trapping-detrapping model at microvoids has then been used in a KMC model to simulate diffusion across a granule which is typically a few microns in size. Finally we extend these models to the centimeter scale and present initial results for hydrogen isotope transport in 3d, porous graphite. (c) 2004 Elsevier B.V. All rights reserved.