The different departments of the Institute of Resource Ecology work in the fields of "radioactive waste management", "radioecology" and "reactor safety". The interdisciplinary approach is focused on the elucidation of the processes and behavior of actinides and fission products at the molecular level and the associated parameterization. Part of the work and focus of this presentation is the work on thermodynamic databases for both solubility (THEREDA) and sorption (RES³T) of radionuclides.