Sensitivity Analysis of Uranium Solubility under Strongly Oxidizing Conditions
1998 (English)In: Proc. Scientific Basis for Nuclear WasteManagement XXII,, 1998, 1001- p.Conference paper (Other academic)
To evaluate the effect of geochemical conditions in the repository on the solubility of uranium under strongly oxidizing conditions, a mathematical model has been developed to determine the solubility, by utilizing a set of non linear algebraic equations to describe the chemical equilibria in the groundwater environment. The model takes into account the predominant precipitation-dissolution reactions, hydrolysis reactions and complexation reactions that may occur under strongly oxidizing conditions. The model also includes the solubilitylimiting solids induced by the presence of carbonate, phosphate, silicate, calcium, and sodium in the groundwater. The thermodynamic equilibrium constants used in the solubility calculations are essentially taken from the NEA Thermochemical Data Base of Uranium, with some modification and some uranium minerals added, such as soddyite, rutherfordite, uranophane, uranyl orthophosphate, and becquerelite. By applying this model, the sensitivities of uranium solubility to variations in the concentrations of various groundwater component species are systematically investigated. The results show that the total analytical concentrations of carbonate, phosphate, silicate, and calcium in deep groundwater play the most important role in determining the solubility of uranium under strongly oxidizing conditions.
Place, publisher, year, edition, pages
1998. 1001- p.
IdentifiersURN: urn:nbn:se:kth:diva-12992OAI: oai:DiVA.org:kth-12992DiVA: diva2:320028
Materials Research Society, Boston, Massachusetts, November 30-December 4, 1998
QC 201005212010-05-212010-05-212010-05-21Bibliographically approved