| Summary: | The safe isolation of high-level radioactive waste from the human environment is a key requisite in the nuclear fuel cycle. Deep geological repositories (i.e. >500m) in a suitable rock mass, involving both engineered and natural barriers is currently the most favoured option for the disposal of high-level nuclear waste. Complex Thermal-Hydro-Mechanical and Chemical (THMC) phenomena are anticipated during the repository lifetime. The formation of gasses (e.g., as a result of oxidation processes) and their possible migration through the engineered barrier system (EBS) could jeopardise the main barrier functions. This paper focuses on the experimental study of the gas flow process through clay-barrier materials, particularly on the effect of degree of saturation, clay initial dry density, and confinement stress on gas permeability. It is shown that the initial dry density of the clay has a significant impact on gas flow, especially at low saturations. As expected, lower gas permeability values were obtained near saturation. Confinement has a minor impact on gas flow, at least for the range of stresses investigated in this paper.
|
|---|
