Kinetic Monte–Carlo modeling of hydrogen retention and re-emission from Tore Supra deposits

A multi-scale model has been developed to study the reactive–diffusive transport of hydrogen in porous graphite [A. Rai, R. Schneider, M. Warrier, J. Nucl. Mater. (submitted for publication). http://dx.doi.org/10.1016/j.jnucmat.2007.08.013.]. The deposits found on the leading edge of the neutralizer of Tore Supra are multi-scale in nature, consisting of micropores with typical size lower than 2 nm (∼11%), mesopores (∼5%) and macropores with a typical size more than 50 nm [C. Martin, M. Richou, W. Sakaily, B. Pégourié, C. Brosset, P. Roubin, J. Nucl. Mater. 363–365 (2007) 1251]. Kinetic Monte–Carlo (KMC) has been used to study the hydrogen transport at meso-scales. Recombination rate and the diffusion coefficient calculated at the meso-scale was used as an input to scale up and analyze the hydrogen transport at macro-scale. A combination of KMC and MCD (Monte–Carlo diffusion) method was used at macro-scales. Flux dependence of hydrogen recycling has been studied. The retention and re-emission analysis of the model has been extended to study the chemical erosion process based on the Küppers–Hopf cycle [M. Wittmann, J. Küppers, J. Nucl. Mater. 227 (1996) 186].