Immobilize simulated Am–Np–RE–Pu product waste from trialkyl phosphine oxide process in natural granite-based aluminum silicate glass or glass–ceramic†

Abstract

The immobilization of nuclear waste can effectively reduce the possible harm of radioactive waste to human survival. In this study, preferred natural granite was used to prepare aluminosilicate glass or glass–ceramic for immobilizing simulated Am–Np–RE–Pu product waste from a trialkyl phosphine oxide (TRPO) process. The phase evolution, microstructure, and physical and chemical stability of the waste forms were researched. The results indicated that the waste cations were mainly incorporated into the glass network or stable oxyapatite crystals. The lattice binding force and the interface effect inhibited the waste cations from escaping out of the glassy bulk. After 42 days of leaching, the normalized leaching rates of Ce, Nd, and La in glass–ceramic reached ∼10⁻⁷ g m⁻² d⁻¹, ∼10⁻⁸ g m⁻² d⁻¹, and ∼10⁻⁷ g m⁻² d⁻¹, respectively. This study demonstrated that the preferred natural granite showed considerable potential in effectively immobilizing high-level radioactive waste rich in rare earth elements.