Modelling of anisotropic damage due to hydrogen production in radioactive waste disposal

The production of hydrogen due to metallic container corrosion is one of the most critical problems related to an underground radioactive waste disposal project. In fact, the increasing hydrogen pressure in the porous network of the host rock may lead to a mechanical damage and consequently increase the risk of environment contamination. This paper proposes an approach to studying this phenomenon by using a hydromechanical model, which accounts for the hydrogen and water flows, the anisotropic mechanical damage and the anisotropic damage-induced permeability change. For a given geometry and material characteristics, a parametric study on the quantity of the produced hydrogen was conducted. Namely, the time of the damage initiation and the extent of the damaged zone were considered. A threshold on the produced quantity, below which the host rock was not damaged, was obtained. This value was found to be considerably higher than the estimates obtained by some studies concerning the corrosion reactions, which is encouraging for the repository project reliability.