resizing the domain to an area that can represent the near field of an installed nuclear water canister,
assuming the the betonite is fully saturated from the beginning,
ignoring the mechanical process.
With such simplifications, the geometry of the present example is illustrated in the following figure:
In the above figure, the domain in the annulus sector represents the sealing material, bentonite. A heat power, which is generated by the nuclear waste with one million year variation, is applied onto the inner arc of the annulus sector. On the top boundary, the boundary conditions are p = 4.3 ⋅ 106 Pa, T = 294 K. While on the bottom boundary, the boundary conditions are set as p = 4.7 ⋅ 106 Pa, T = 310 K. The initial conditions are given as p = 4.7 ⋅ 106 Pa, T = 298 K.
The material properties are shown in the following table:
|Specific heat capacity||J/(kgK)||3|
|Saturated permeability||m2||2.0 ⋅ 10−21|
|Specific heat capacity||J/(kgK)||900|
As the reference results, the temperature and pressure distributions in the domain at the time of 18 years are shown in the following figure, in which the thermal convection effective can be seen clearly.
Birkholzer, J. and Rutqvist, J. and Sonnenthal, E. and Barr, D. ( 2008 ): DECOVALEX-THMC Project, Task D: Long-term permeability/porosity changes in the EDZ and near field due to THM and THC processes in volcanic and crystalline-bentonite systems. SKI