Heavy-Ion Radiation Stability of Gd₂Zr₂O₇-Pyrochlore Glass-Ceramic Wasteforms Doped by Simulated Actinides

To research the structure radiation stability of simulated Gd₂Zr₂O₇-pyrochlore glass-ceramic wasteforms, Nd³⁺ and Ce⁴⁺ were selected as the simulated nuclides of An³⁺ and An⁴⁺ radionuclides, respectively. A series of compounds with the general formula Gd_2−xNd_xZr_2−xCe_xO₇ (0.0 ≤ x ≤ 2.0) were prepared by high-temperature sintering method at 1,623 K for 48 h in air atmosphere. The heavy-ion irradiation experiments were done at room temperature and atmospheric pressure. The structure and microscopic morphology of Gd_2−xNd_xZr_2−xCe_xO₇ (0.0 ≤ x ≤ 2.0) glass-ceramic wasteforms before and after irradiation experiments were investigated by the X-ray diffraction and scanning electron microscopy. The results showed that Gd_2−xNd_xZr_2−xCe_xO₇ (0.0 ≤ x ≤ 2.0) glass-ceramic wasteforms exhibited pyrochlore phase within the scope of the wholly solid solution. With the added amount of analog nuclides increasing, the X-ray diffraction peak of wasteforms had a trend of moving in the direction of the small angle. XRD patterns and SEM photos suggested the series of wasteforms containing both crystalline phase and glass phase. The structure and microscopic morphology of wasteforms didn’t change significantly before and after irradiation according to the XRD spectra and SEM photos. The Gd₂Zr₂O₇-pyrochlore glass-ceramic wasteforms showed a good radiation stability.