Thermal null state

By choosing the null reference thermal stress state at t > 0 so that ... 

To get better the understanding of the system, the mechanical behaviour of the clay has been taken into account. The initial conditions are null total stresses everywhere. So, in-situ mechanical stresses are not taken into account. The results of our THM calculation show only stresses induced by thermal-hydro-mechanical couplings. The contact between the EB and the canister is once again supposed to be perfect, so that no radial displacement of the clay is allowed at that boundary. Biot s poroelastic model is chosen to represent clay behaviour. It takes partial saturation into account via an equivalent pressure which includes capillary effects, involving both gas and liquid, Dangla (1998). Biot s model is added as fourth equation to the system. The associated main variable is total stress state. The couplings with thermal-hydraulics behaviour are introduced by... 

The conventional way states that during a transformation occurring in an isolated system containing thermal energy, the variation of entropy is always positive or null (Planck 1922). 

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