Competition Between Internal and Surface Crystallization in Glass-ceramics Developed for Actinides Immobilization
Published online by Cambridge University Press: 01 February 2011
Glass-ceramic matrices containing zirconolite (nominally CaZrTi2O7) as the only crystalline phase in their bulk can be considered as good candidates for actinide-rich nuclear wastes (containing minor actinides or Pu) immobilization. In this study, three different methods are envisaged and compared to prepare such waste forms using neodymium as trivalent actinides surrogate. Independently on the preparation method, zirconolite is shown to be the only crystalline phase to nucleate in the bulk. However, crystallization of silicate phases (titanite CaTiSiO5 + anorthite CaAl2Si2O8) can occur from samples surface and can compete with zirconolite crystallization. The effect of the crystal growth thermal treatment duration (2–300 h) at high temperature (1050–1200°C) on glass-ceramics structure and microstructure is studied. In the oxides system studied here, it appears that zirconolite is not thermodynamically stable in comparison with titanite but, for kinetics reasons, such transformation will not occur during waste forms disposal.
- Research Article
- MRS Online Proceedings Library (OPL) , Volume 807: Symposium Scientific Basis for Nuclear Waste Management XXVII , 2003 , 333
- Copyright © Materials Research Society 2004