Author(s)

Pedro Orrego Alfaro¹, José Hernández Torres¹, Fernando Puchi Thiele²

¹Sección de Geología y Minería, Departamento de Materiales Nucleares, Comisión Chilena de Energía Nuclear, Santiago, Chile.
²Ingeniería Civil Metalurgia, Universidad Andrés Bello, Santiago, Chile.

This article presents a study on the kinetics of the uranium conversion process, consisting in the reduction of uranium trioxide to uranium dioxide using hydrogen gas at temperatures of 500°C, 600°C and 700°C. Hydrogen concentrations used in the flow were 0.25 M, 0.50 M and 0.75 M. The mechanism established for the study of the kinetics of reduction of uranium trioxide was through the formation of an intermediate compound, U₃O₈. For this reason, these tests were divided into 2 stages: the first one the reduction from UO₃ to U₃O₈, and second one from U₃O₈ to UO₂. The results of each test were quantified by the release of H₂O(g) produced by both reactions. Tests showed that the ideal working conditions are for hydrogen concentration flows of 0.75 M and temperatures in the range of 500°C - 600°C, with the intent to decrease the occurrence of side reactions that interfere with the process.

Conversion, Uranium Oxides, Nuclear Fuel Cycle

Alfaro, P. , Torres, J. and Thiele, F. (2015) Reduction Kinetics of Uranium Trioxide to Uranium Dioxide Using Hydrogen. World Journal of Nuclear Science and Technology, 5, 149-156. doi: 10.4236/wjnst.2015.53015.