FZK
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Forschungszentrum Karlruhe GmbH |
The Institut für Nukleare Entsorgung (INE) is part of the Forschungszentrum Karlsruhe GmbH (FZK), an independent science and research institution in Germany with a staff of about 3500 employees, in the area of technology and the environment. It is owned by the Federal Republic of Germany and the Land Baden-Wuerttemberg and a member of the Helmholtz Association of National Research Centres (HGF). The research activities at the INE on the Topic “Safety Research for Nuclear Waste Disposal” are integrated within the HGF Programme “Energy: Nuclear Safety Research”. Besides technical developments on the vitrification of high-level waste and research work on the partitioning of actinides from high-level radioactive waste, the main research activities at FZK are addressed to “Long-term safety of nuclear waste disposal”.
The research activities at FZK/INE are focussed on actinides and on some long lived fission products, since they make the greatest contribution to the radio-toxicity of disposed radioactive waste over long periods of time. Basic understanding of geochemical processes and quantification of the ongoing reactions is a prerequisite for predicting long-term behaviour of actinides and, therefore, essential for safety analyses. INE therefore currently develops five main research topics in actinide chemistry related to nuclear waste disposal:
Chemistry and thermodynamic of actinides in aqueous solution: Basis for quantification of actinides in aquatic systems is the determination of thermodynamic data for dissolved actinides species in the prevailing oxidation levels for hydrolysis and complexation reactions. FZK has contributed to complete the database of aqueous actinide ions. However, in some areas such as formation of ternary complexes or reactions at elevated temperature, further efforts are required.
- Interaction of Actinides with Mineral Surfaces: Reactions of actinide ions at the mineral/electrolyte interface of selected mineral phases are studied by a combination of classical wet-chemistry and laser-spectroscopic methods.
- Coprecipitation of Actinides in Secondary Phases: The incorporation of trivalent actinides by coprecipitation from aqueous solution was observed in calcite, hydroxoalumosilicate and powellite for the first time by laser fluorescence spectroscopy. Experiments using a mixed-flow reactor and spectroscopic, microsopic and diffraction methods will be used to synthesise secondary phases and to identify the incorporation mechanisms at the molecular level.
- Colloid Facilitated Transport of Actinides: Aquatic colloids are considered to have a considerable influence on the chemical speciation and the mobility of actinide ions in a natural aquifer. FZK develops sensitive colloid characterisation methods and studies the interaction of actinides with colloids, including with in-situ experiments (e.g. Äspö, HRL, Sweden and Grimsel Test Site, GTS, Switzerland).
- Development and application of speciation methods: Various spectroscopy methods are being developed at FZK to improve our understanding of relevant geochemical processes on a molecular level. Furthermore, an important impact on the future spectroscopic capabilities at FZK is expected by commissioning the active beam-line at the ANKA synchrotron source in 2004.
FZK will contribute to the setting of the ACTINET multi-site user facility by pooling a number of instruments for actinide geochemistry and waste behaviour studies.
For more information: http://www.fzk.de.
Address
Forschungzentrum Karlsruhe GmbH, Institut für Nukleare Entsorgung
P.O. Box 3640
76021 Karlsruhe
Germany
Contactperson(s)
Reinhardt KLENZE
+49 (0) 72 47 82 46 02
+49 (0) 72 47 82 43 08
