Kinetics of Reduction and Precipitation of U(VI) in the Dissolution of UO2(s) Under Anoxic Conditions in NaCl 5 mol kg−1. Influence of Metallic Iron

Abstract

ABSTRACTExperiments of spent fuel dissolution performed in presence of iron show, for uranium as well as for some radionuclides, lower final concentrations than measured in similar experiments but in absence of iron. So far, only the final concentrations obtained in these experiments have been published. In this work, we have focused our study on the reduction of uranium (VI) due to the presence of iron and the subsequent precipitation of Uranium (IV) due to its lower solubility. This behavior has been confirmed using a Scanning Electron Microscope by observing an uranium phase precipitated on the iron surface and assuming, under the experimental conditions, that it most likely corresponds to U02(s). We have modeled this process assuming a first-order kinetic.