IR and Raman spectroscopy of sodium aluminophosphate vitreous materials for immobilization of high level wastes from nuclear fuel reprocessing

The structure of sodium aluminophosphate vitreous materials containing constituents of high level wastes (cesium, magnesium, copper and molybdenum oxides) from uranium-graphite reactor has been studied by IR and Raman spectroscopy techniques coupled with X-ray diffraction. The structural network has been shown to be composed of short phosphorus-oxygen chains with embedded aluminum-oxygen tetrahedra. In the magnesium-bearing samples the cross-linking with Mg2+ ions is possible. The effect of other oxides (Cs2O, MoO3, CuO) on the glass structure is negligible for the occuring amounts. The glasses have been devitrified partly at the quenching and much stronger at the annealing. It is reflected in splitting of the vibration bands of the bonds in structural units of the anionic motif of the vitreous materials. (authors)