Helium irradiation effects on MgO-Nd2Zr2O7 composite ceramics prepared by one-step method used for inert matrix fuel

Abstract

In this work, the helium irradiation effects were systematically investigated on MgO-Nd2Zr2O7 (hereafter M-NZO) composite ceramics used for inert matrix fuel, in which the ion fluences range from 5 × 1016 to 3 × 1017 ions/cm2 at room temperature. It was demonstrated that M-NZO composite ceramic shows superior radiation tolerance after He implantation. Specifically, MgO had almost no phase transition and extensive amorphization. And Nd2Zr2O7 phase possessed slightly pyrochlore-fluorite-amorphization structural transformation, while part of Nd2Zr2O7 maintained the ordered pyrochlore structure and co-existed with the irradiation-induced disordered fluorite structure. Importantly, GIXRD results indicated that MgO phase presents higher resistance to radiated damage than Nd2Zr2O7 phase. Besides, SEM images illustrated that MgO particles have substantially less fragmentation than Nd2Zr2O7 particles due to the higher thermal conductivity of MgO. It reconfirmed that MgO phase resists irradiation damage better than Nd2Zr2O7 phase in post-irradiated M-NZO composite ceramics.