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Center for Nonlinear Studies |
The aquatic chemistry and thermodynamics of long-lived actinides as well as fission and activation products have been investigated over the last decades from many different perspectives. Owing to the exceptionally high importance in several nuclear waste disposal scenarios, the detailed study of aqueous radionuclide chemistry is still an especially important focus of recent research activities. The main driving force for progress in aquatic actinide and fission product chemistry over the last decade is related to the frequent use of advanced spectroscopic tools for investigating chemical speciation at the molecular level. The technical progress in modern analytics has been directly translated into a significantly improved understanding of actinide and fission product chemistry. Based upon new chemical and structural information, a more detailed picture of radionuclide speciation is becoming available, generating advanced process understanding and input for more realistic chemical models. Computational chemistry also has developed into a valuable tool for actinide science as it offers information from a quantum chemical perspective to complement conventional chemical approaches. Thermodynamic data and databases have been significantly improved by the Thermodynamic Database Project of the OECD-NEA. The NEA-TDB project has published a series of expertly reviewed and evaluated compilations of consistent thermodynamic data widely accepted as reference data for many key elements and ligands.
In this talk, an overview on recent studies at KIT-INE on aquatic actinide and fission product chemistry will be given. The need to continuously dedicate research efforts to aqueous actinide and fission product chemistry and thermodynamics will be critically reflected against the progress made in this research field over the last decades. It is concluded that it remains essential to improve the quality of chemical models and reduce present systematic and data uncertainties as a key contribution to repository safety. It will be especially important to fill relevant data gaps and improve data for more complex geochemical systems, e.g. high ionic strength systems, kinetically controlled processes, redox transformations or aquatic chemistry at elevated temperatures. The need for international networking and scientific exchange is likewise emphasized and pointed out as a powerful instrument to effectively optimize the scientific description and understanding of radionuclide chemistry.
BIO: Xavier Gaona earned his PhD in Analytical Chemistry (2004) from the Universitat Autonoma de Barcelona (Spain). He went on to join Amphos 21, where he developed consultancy projects in the department of Nuclear Waste Management. In 2008, he moved on as a post-doc fellow to the laboratory of Waste Management at the Paul Scherrer Institute (Switzerland). Since 2010 he is working at the Institute for Nuclear Waste Disposal (INE) at the Karlsruhe Institute of Technology (KIT) (Germany), where he leads the working group on “Aquatic Chemistry and Thermodynamics of Actinides and long-lived Fission Productsâ€. In 2022, Xavier was appointed as deputy director of the Radiochemistry Division at KIT-INE. His research interests focus on the aquatic chemistry and thermodynamics of actinides, fission and activation products, with special emphasis on repository-relevant processes and conditions. He has published more than 80 peer review publications and has contributed to reference books in the field of Actinide chemistry, e.g. the Plutonium Handbook or the OECD NEA-TDB update book on U, Np, Pu, Am and Tc, where he acted as co-chair. Since 2019, Xavier serves as Scientific Secretary of the Migration conference
Host: Seaborg Institute