Numerical Implementation Of A Multivariable Thermomechanical Model For Unsaturated Bentonite

V-M. Pulkkanen, and M. Olin
VTT Technical Research Centre of Finland, Espoo, Finland

A compacted bentonite clay buffer is planned to be used as a part of the engineered barrier system in the KBS-3 concept for the disposal of spent nuclear fuel. Simulations together with experimental studies are needed to ensure that bentonite fulfills its safety functions in the concept. In this paper, one type of bentonite model, namely a thermomechanical model developed by Jussila, is presented in brief and its numerical implementation with COMSOL Multiphysics 4.0 is discussed. The model describes bentonite as a mixture of four components: solid skeleton, liquid water, water vapour, and air. Previously, the model has been implemented with software called Elmer by CSC – IT Center for Science and with an in-house code Numerrin by Numerola that has made some extensions to the model. By implementing the model with COMSOL Multiphysics we will be able to test and develop the model ourselves and compare the results with those of others.