Preparation of uranium(III) in a molten chloride salt: a redox mechanistic study

Hugues Lambert; Timothy Kerry; Clint A Sharrad

doi:10.1007/s10967-018-5953-7

Preparation of uranium(III) in a molten chloride salt: a redox mechanistic study

J Radioanal Nucl Chem. 2018;317(2):925-932. doi: 10.1007/s10967-018-5953-7. Epub 2018 Jun 28.

Authors

Hugues Lambert^{1

2}, Timothy Kerry^{1

3}, Clint A Sharrad¹

Affiliations

¹ 1School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL UK.
² Present Address: Lhoist Recherche et Développement, Business Innovation Cente, 31, rue de l'Industrie, 1400 Nivelles, Belgium.
³ 3Present Address: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands.

Abstract

The most advanced methodology for the pyroprocessing of spent nuclear fuel is the electrorefining of uranium metal in LiCl-KCl eutectic, in which uranium is solubilized as U(III). The production of U(III) in LiCl-KCl eutectic by the chlorination of uranium metal using BiCl₃ has been performed for research purposes. In this work, this reaction was studied in-situ by visual observation, electronic absorption spectroscopy and electrochemistry at 450 °C. The most likely mechanism has been determined to involve the initial direct oxidation of uranium metal by Bi(III) to U(IV). The dissolved U(IV) then reacts with unreacted uranium metal to form U(III).

Keywords: Cyclic voltammetry; Electronic absorption spectroscopy; Molten salts; Open circuit potential; Uranium(III).