Geochemistry of the actinide elements

M.A. Denecke

Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, PO Box 3640, D-76021 Karlsruhe, Germany

The European Commission Integrated Infrastructure Initiative ACTINET i3 has the broad aim of advancing our understanding of the very specific chemical and physical properties of the actinide elements. Understanding the behavior of the actinide elements in the environment is one of the four scope topics of ACTINET i3. This scope was also included in the predecessor to ACTINET i3, the European FP6 Network of Excellence in Actinide Science, ACTINET. Through pooling resources (including state-of-the-art instrumentation and theoretical tools) and network activities, thermodynamic actinide aquatic chemistry databases and our knowledge of processes determinant in actinide geochemistry such as colloid generation/stability, solid/liquid interface reactions, and biogeochemical reactions should significantly improve. Activities in these European ACTINET projects have led to improvement of our understanding of, e.g., redox chemistry of plutonium [1] or actinide eigencolloid formation [2]. Despite such advances in our knowledge of actinide geochemistry, which are partially driven by increasing sophistication of available instrumentation and methods, a number of open questions related to actinide behavior in environmental systems remains. Future results of combined European, as well as global, efforts should further contribute not only to increasing understanding of actinide geochemistry, thereby improving the reliability in predicting long-term safety of nuclear waste repositories and waste legacies, but will also lead to interesting actinide science.

[1] V. Neck, M. Altmaier, Th. Fanghaenel (2007) Comptes Rendus Chimie 10, 959-977.

[2] C. Walther, J. Rothe, B. Brendebach, M. Fuss, M. Altmaier, C. M. Marquardt, S. Büchner, H.-R. Cho, J.-I. Yun, A. Seibert (2009) Radiochim. Acta 97, 199–207.

KEYWORDS: actinide geochemistry