In performance assessment a sequence of models is used to describe the function of the geological barrier. This report proposes a general structure and terminology for description of these models. A model description consists of the following components: A conceptual model which defines the geometric framework in which the problem is solved, the dimensions of the modelled volume, descriptions of the processes included in the model, and the boundary conditions; Data which are introduced into the conceptual model, and a mathematical or numerical tool used to produce output data. Contradictory to common practice in geohydrologic modelling it is proposed that the term conceptual model is restricted to define in what way the model is constructed, and that this is separated from any specific application of the conceptual model. Hence, the conceptual model should not include any specific data. 5 refs, 2 figs, 4 tabs.
Olsson, Olle;  Baeckblom, G; Wikberg, P;  Gustafson, G;  Rhen, I;  Stanfors, R 
- Conterra AB, Uppsala (Sweden)
- Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)
- Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Geology
- VBB/VIAK, Stockholm (Sweden)
- RS Consulting, Stockholm (Sweden)