On the Problem of Consistency of Chemical Thermodynamic Data Bases

Abstract

ABSTRACTThe geochemical modelling in support of the performance assessment of radioactive waste disposal systems calls for a large number of chemical thermodynamic data. For realistic modelling it is essential that the data used are fully consistent. The verification of consistency of existing data bases is complicated by the fact that it requires the knowledge of a considerable amount of primary information to ensure:1.Consistency with the fundamental laws of thermodynamics2.Consistency within a chemical model3.Consistency with auxiliary data4.Consistency in the data correction proceduresThis paper includes selected examples for each of the four items to visualize the problems. It should be noted that there are numerous other systems that could serve as examples as well, and the range of cases reported here is far from being exhaustive.Realistic geochemical modelling depends not only on the quality of the data base, but also on the quality of the chemical model used. For the establishment of a chemical model, additional information is needed that is not contained in thermodynamic data bases.