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 MD 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.