The NOx System in Homogeneous and Heterogeneous Nuclear Waste

This project focuses on the development of reliable theoretical and efficient computational descriptions of the chemistry of high-level waste simulants in highly concentrated solution and the experimental validation of this approach. It is an extension of previous work which: (a) Determined the mechanism of H{sub 2} formation in waste simulants allowing quantitative prediction of H{sub 2} generation in nuclear waste storage tanks; (b) Predicted and confirmed NO{sub 2} as a key oxidant in the tanks (c) Determined relative rates of reaction of NO{sub 2} with chelators thus helping to resolve the ''Organic Tanks'' safety issue; (d) Measured rates of NO{sub 2} and NO{sub 2}{sup -} with some model organic radicals; (e) Quantified the redox potentials of two major reductants, NO{sub 2}{sup -} and NO{sub 3}{sup -}; (f) Discovered a new radiolytic route to the reductant NO{sub 3}{sup 2-} and demonstrated its potential persistence in irradiated alkaline aqueous media; (g) Demonstrated that while radiolytic electrons escape from solid suspended silica particles to disrupt the surroundings, holes remain trapped thus storing oxidative equivalents