Objectif The project aims to improve the scientific basis for the assessment of performance and safety in waste management. It will provide fundamental knowledge about the behaviour of actinides and fission products in natural aquatic systems.The project focuses on key areas where further research is essential, including:i) understanding of the mechanisms that govern the interaction of actinides and fission products in natural aquatic systems;ii) closing existing gaps in the available thermodynamic database; andiii) reducing uncertainities in currently used constants. Investigations focus on the thermodynamics of aquatic actinide ions, particularly in the tetravalent oxidation state, on the interaction of actinides and fission products at the solid/aqueous solution interface and on the thermodynamics of secondary solid phases. A link will established to theoretical methods for prediction of chemical behaviour in actinide systems.A notable breakthrough has been achieved filling serious gaps in the database for tetravalent actinides, necessary e.g. to predict the geochemical of plutonium. The understanding of actinide complexation with small organic ligands, which may serve as model compound for natural organic matter, has been substantially increased using various spectroscopic methods and theoretical approaches. Computational methods (molecular modelling) have been applied for the first time to chemical problems related to nuclear waste disposal.An improved understanding of actinides interaction at the mineral/groundwater interface and sound sorption data have been provided. Mechanistic insight into the sorption of U(VI) on iron oxides including surface enhanced redox reactions has been achieved as well as the elucidation of the speciation of trivalent actinides sorbed onto alumina and clay minerals. Sorption reaction at single crystals have been studied by grazing incidence X-ray absorption spectroscopy and laser fluorescence spectroscopy. For the prediction of the U(VI) sorption onto rock minerals, a 'composite' model has been parameterised successfully using sorption data derived for the mineralogical rock constituents.The combination of wet chemical methods, surface analysis and spectroscopic techniques available in the different laboratories of the project partners helped in improve the basic understanding of solid solution formation of actinides in calcite, cement degradation secondary phases and phosphates. Such mineralisation processes are believed to be of cardinal importance for the actinide reactions in the near and the far field of a nuclear waste repository. The results gained in the ACTAF project indicate that inclusion in secondary phases can lead to a strong actinide retention in the repository or the surrounding geosphere. Champ scientifique engineering and technologyother engineering and technologiesnuclear engineeringnuclear waste managementnatural sciencesphysical sciencesnuclear physicsnuclear fissionnatural sciencesphysical sciencesthermodynamicsnatural sciencesphysical sciencesopticsspectroscopyemission spectroscopynatural sciencesphysical sciencesopticsspectroscopyabsorption spectroscopy Programme(s) FP5-EAECTP C - Research and training programme (Euratom) in the field of nuclear energy (1998 to 2002) Thème(s) 2.1.2.-2.1.5 - Long-term behaviour of repository systems Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur FORSCHUNGSZENTRUM KARLSRUHE GMBH - TECHNIK UND UMWELT Contribution de l’UE Aucune donnée Adresse Herrmann-von-Helmholtz-Platz 1 76344 EGGENSTEIN-LEOPOLDSHAFEN Allemagne Voir sur la carte Coût total Aucune donnée Participants (7) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire CENTRO DE INVESTIGACIONES ENERGETICAS, MEDIAMBIENTALES Y TECNOLOGICAS Espagne Contribution de l’UE Aucune donnée Adresse 22,Avenida Complutense 22 28040 MADRID Voir sur la carte Coût total Aucune donnée ENTERPRIS LIMITED Royaume-Uni Contribution de l’UE Aucune donnée Adresse Pris, University of Reading, Whiteknights RG6 6AB READING / SILCHESTER Voir sur la carte Coût total Aucune donnée PAUL SCHERRER INSTITUT Suisse Contribution de l’UE Aucune donnée Adresse 5232 VILLIGEN Voir sur la carte Coût total Aucune donnée RESEARCH CENTER ROSSENDORF Allemagne Contribution de l’UE Aucune donnée Adresse Bautzener Strasse 128 01314 WEISSIG - DRESDEN Voir sur la carte Coût total Aucune donnée ROYAL INSTITUTE OF TECHNOLOGY Suède Contribution de l’UE Aucune donnée Adresse Teknikringen 30 100 44 STOCKHOLM Voir sur la carte Coût total Aucune donnée UNIVERSITAT POLITECNICA DE CATALUNYA Espagne Contribution de l’UE Aucune donnée Adresse P.I. Els Dolors - Palau Firal 08240 MANRESA Voir sur la carte Coût total Aucune donnée UNIVERSITY OF COPENHAGEN Danemark Contribution de l’UE Aucune donnée Adresse Oester Voldgade 10 1350 KOEBENHAVN K/COPENHAEGEN Voir sur la carte Coût total Aucune donnée