Kinetic Monte-Carlo Modeling of Hydrogen Retention and Re-emission From Tore-Supra Deposits

Full text of publication follows: The understanding of retention and re-emission of hydrogen in graphites, carbon based materials and co-deposited layers is important for fusion plasma density control and for the determination of tritium inventory in future fusion machines. The hydrocarbon deposits found on the leading edge of the neutralizer of Tore-Supra consists of micropores with typical size lower than 2 nm (∼ 11%), meso-pores (∼ 5%) and macro-pores with a typical size more than 50 nm [1]. The meso-pores and micropores are slit shaped. We use kinetic Monte-Carlo to study the reactive-diffusive transport of hydrogen in a 3D, porous geometry typical of the Tore-Supra co-deposited layers. Sensitivity studies on the effect of the internal structure i.e. void fraction, void size and void orientation has been done. An extension of this model is presented, including chemical erosion process based on the Kueppers-Hopf cycle [2]. [1] C. Martin, M. Richou, W. Sakaily, B. Pegourie, C. Brosset and P. Roubin. To be published in J. Nucl. Mater., Proceedings of PSI-17. [2] M. Wittmann and J. Kueppers, J. Nucl. Mater.,227 (1996), 186. (authors)