Vapour and gas flow in clay barriers: formulation and analysis

摘要

A compacted clay barrier isolating radioactive waste is subjected to several water and gas flow processes that are coupled to heat and mechanical effects. Water hydration from the host rock takes place simultaneously with water evaporation due to heating. This implies liquid water flow and vapour migration in the pore space. Also, gas generation induced by corrosion of the canister will eventually occur, probably after saturation of the barrier. In the paper, a formulation for coupled thermo-hydro-mechanical in clay barriers is first presented. Afterwards, the issue of permeability of compacted swelling clays considering hydration effects is discussed. Finally, the analysis of the long-term behaviour of a clay barrier under heating, hydration and gas generation is examined.