Published online by Cambridge University Press: 10 February 2011
High-FeO olivine-rock from Lovasjäarvi intrusion (SE-Finland) has been suggested as redox-active backfill-additive in deep high level nuclear waste repositories. In this w'ork, surface characterization of olivine-rock by X-Ray Photoelectron Spectroscopy (XPS) has been used in order to assess the behavior of this rock during leaching experiments and sorption properties of redox sensitive radionuclides. Uranium (VI) sorption has also been performed. Olivine leaching experiments at basic pH have shown the abundance of Fe and 0 relative to Si and Mg clearly indicating the precipitation of a Fe(III)-oxide secondary phase, probably amorphous FeOOH. At acid pH, the decrease of Mg/Si and Fe/Si ratios can be attributed to the formation of silicon dioxide on the mineral surface. The deconvolution of the 4f7 2 Uranium peak has shown the reduction of U(VI) to U(IV) onto the olivine surface.