Geochemical modelling of repository systems: limitations of the thermodynamic approach

In the light of their relevance for performance assessment, results from cement degradation modelling and solubility limit evaluations in cementitious systems are illustrated, but the main emphasis is put on the role and limitations of the thermodynamic approach. It is concluded that research on flow system properties is needed to further improve our understanding of cement performance. It is proposed to complement thermodynamic modelling with system-dependent features and processes like inventories, sorption and co-precipitation, isotopic dilution etc. (orig.)