Crystallization behavior of uranium glass-ceramic matrix under simulated self-irradiation conditions

The study of irradiation stability for radioactive waste matrices is essential for efficient long-term waste management. The uranium-contaminated soil was vitrified using microwave technology in the current study, and the irradiation response mechanism was examined using 0.5 MeV He ²⁺ ions to approximately imitate self-irradiation. The results demonstrate that the glass matrices with differing uranium contents showed various irradiation response mechanisms. The stability of the matrix with lower uranium content (0 and 500 μg/g) may be slightly impacted by the ions irradiation, as one may see a crystallization behavior for the matrix with 50,000 μg/g uranium after being irradiated to He ²⁺ ions at a fluence of 1 × 10 ¹⁷ ions/cm ². The crystalline phase (SiO ₂ ) was identified via phase investigations and microscopic studies. As a result of the crystallization event, the Vickers hardness of the matrix decreased from 6.88 GPa to 6.77 GPa after irradiation. Additionally, the un-irradiated matrix containing 50,000 μg/g of uranium had a uranium leaching rate of 3.2 × 10 ⁻⁵ g·m ⁻²·d ⁻¹ at 28 days. The leaching rate for the irradiated matrix under the identical experimental conditions is 5.4 × 10 ⁻⁵ g·m ⁻²·d ⁻¹, demonstrating that the crystallization behavior affects the chemical stability.