Binding models concerning natural organic substances in performance assessment

Natural organic substances (i.e., humic and fulvic acids) are important in radioactive waste disposal programmes for predicting the fate of radionuclides migration in the environment. A recent workshop organised by the OECD Nuclear Energy Agency, in co-operation with the Paul Scherrer Institute (Switzerland), brought together experts from various Nea Member countries to discuss and review the current evaluation of natural organic substances, their characterisation and isolation, documentation on existing mathematical models, competition with inorganic ligands in forming radionuclide complexes, and their influence in performance assessment for a variety of geologic media. These proceedings present the papers submitted at the workshop and a summary of the discussions on the role of organic substances in performance assessment. (authors). 432 refs., 119 figs., 53 tabs