Heavy-ion irradiation effects on Gd2Zr2O7 ceramics bearing complex nuclear waste

The irradiation response of Gd₂Zr₂O₇ ceramic bearing complex nuclear waste was explored by heavy ions to relatively high fluences. The Gd₂Zr₂O₇ ceramic holding 25 wt.% and 40 wt.% of simulated TRPO waste (containing 11 kinds of oxides) were irradiated by 1.5 MeV Xe²⁰⁺ to fluences ranging from 1.0 × 10¹² ions/cm² to 1.0 × 10¹⁵ ions/cm² at room temperature. Irradiation induced structure disordering (i.e. phase transformation from pyrochlore to defect-fluorite and finally to amorphous structure) was disclosed by GIXRD, Raman and TEM. The results indicated the structure disordering was influenced by fluences, irradiation depth and waste loading content. This work identified the Gd₂Zr₂O₇ ceramics as a potential candidate in immobilizing complex oxides from the aspect of irradiation tolerance.