Niobium modified glass for nuclear waste immobilization

The impact of Nb₂O₅ addition to glasses belonging to the system SiO₂-Na₂O-CaO-B₂O₅-Al₂O₃ were investigated for nuclear waste immobilization applications. The glass samples, produced by the traditional melting method, were characterized by XRD, Differential Thermal Analysis (DTA) and Fourier-Transform Infrared Spectroscopy (FT-IR). The XRD results confirmed the amorphous state of the glasses and the thermal and FT-IR analyses revealed that Nb₂O₅ was dispersedly incorporated to the glass structure and that higher contents of the oxide result in a niobate network growth. The glasses showed good resistance to devitrification and are applicable for nuclear waste vitrification processes. These results show that the process is a promising alternative to produce a new family of glasses with optimized thermal resistance for the immobilization of nuclear wastes. (author)