Converting natural metamorphic granite and simulated actinide oxide to aluminosilicate glass for nuclear waste immobilization

Abstract

To explore the possibility of immobilizing nuclear waste by natural metamorphic granite, the phase, microscopic morphology, elemental distribution and the structural evolution of the final waste form were studied. The maximum loading capacity of natural metamorphic granite to simulated nuclear waste (CeO2) can reach 23 wt%, with half of Ce4+ is reduced to Ce3+ at high temperatures. The mechanical stability of the glass is well kept after waste doping, and the normalized leaching rate of Ce of waste forms is ∼10−6 g/(m2·d) after 42 d. The results indicate that natural metamorphic granite is a stable host matrix for nuclear waste immobilization, which contributes to environmental protection.