- Published on 10 April 2018
With the goal of understanding and modelling the reactive dissolution of solids, new microscopic methods have been developed for the investigations of the phenomena and kinetics of these reactions, and applied to the dissolution of uranium dioxide in nitric acid media.
The first paper presents a state of knowledge of the dissolution of uranium dioxide in nitric acid media. It highlights the numerous chemical and physico-chemical issues which still need to be addressed concerning its understanding, with a focus on autocatalysis, mass-transport and non-uniform attack of the solids.
The second article presents a novel approach for the phenomenological and kinetics study of dissolution. Based on microscopy and image processing, it allows the measurement of the dissolution rate. By allowing a clear discrimination between the rate determining steps in the measurements, endorsed by the absence of non-uniform attack and bubbling at the microscopic scale, it allows the determination of the true parameters of the non-catalyzed component of the chemical kinetics law.
Finally, the last paper presents the latest improvements of the method. They are applied to the determination of the parameters of the autocatalyzed component of the chemical kinetics law, and highlight the role of liquid-gas exchange on this component.
Philippe Marc, Alastair Magnaldo, Jérémy Godard, Éric Schaer, A method for phenomenological and chemical kinetics study of autocatalytic reactive dissolution by optical microscopy The case of uranium dioxide dissolution in nitric acid media, EPJ Nuclear Sci. Technol. 4, 2 (2018))
Florence Charlier, Delphine Canion, Anthony Gravinese, Alastair Magnaldo, Sophie Lalleman, Gilles Borda, Éric Schaer, Formalization of the kinetics for autocatalytic dissolutions. Focus on the dissolution of uranium dioxide in nitric medium, EPJ Nuclear Sci. Technol. 3, 26 (2017))