Development and application of the Nagra/PSI Chemical Thermodynamic Data Base 01/01
Tres Thoenen, Urs Berner, Enzo Curti, Wolfgang Hummel, F. J. Pearson, 2004. "Development and application of the Nagra/PSI Chemical Thermodynamic Data Base 01/01", Energy, Waste and the Environment: a Geochemical Perspective, R. Gieré, P. Stille
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The Nagra/PSI Chemical Thermodynamic Data Base is a critical selection of thermodynamic data used to support performance assessments for planned radioactive waste repositories in Switzerland. For this purpose, the data base is focused on actinides and fission products, but also includes additional data for major elements occurring in common groundwaters. Recently, a peer-reviewed update was carried out (from data base version 05/92 to 01/01) involving major revisions for most actinides and fission products. Altogether, more than 70% of the data base contents have been revised. Most of the thermodynamic data for U, Np, Pu, Am, and Tc were adopted from the reviews by the NEA TDB project. In contrast, data for Th, Sn, Eu, Pd, Al, as well as the solubility and metal complexation of sulphides and silicates, were extensively reviewed. Less effort was put into the review of data for Zr, Ni, and Se as these elements are currently being reviewed in Phase II of the NEA TDB project. The data for metal complexation with organic ligands from data base version 05/92 were not included in this update. They will be reconsidered in a future update, after completion of the NEA TDB Phase II review of organic ligands. The chemical consistency of the selected data was checked with empirical rules related to the periodic properties of the elements and with correlations based on charge/size relations. As a result of the update, major gaps in the data base could be identified, especially with respect to missing carbonate complexes. In some systems, for example, Th(IV)-H2O and U(IV)-H2O, conflicting experimental data cannot be described by a unique set of thermodynamic constants and a pragmatic approach closely reproducing measured solubility data was chosen for application to performance assessment. The electronic version of the Nagra/PSI Chemical Thermodynamic Data Base 01/01 and information concerning its full documentation is available on the PSI web site.
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This book provides incentives for further development of sustainable fuel cycles through a novel and interdisciplinary approach to an Earth science-related topic. The main focus is on geochemical concepts in immobilizing, isolating or neutralizing waste derived from energy production and consumption. The book also addresses the issue of using some types of energy-derived waste as alternative raw materials. Moreover, it highlights research on how certain wastes can be used for energy production, an increasingly important aspect of modern integrated waste management strategies. The main objectives are to: (a) identify the most serious environmental problems related to various types of power generation and associated waste accumulation; (b) present strategies, based on natural analogue materials, for the immobilization of toxic and radioactive waste components through mineralogical barriers; (c) discuss modern procedures for reuse of waste or certain waste components; and (d) review the importance of geochemical modelling in describing and predicting the interaction between waste and the environment.