Radiation stability of gadolinium zirconate: a waste form for plutonium disposition

摘要

Zirconate and titanate pyrochlores were subjected to1 MeV of Kr~+ irradiation. Pyrochlores in the Gd_2(Zr_xTi_(1-x))_2O_7 system (x = 0, 0.25, 0.5, 0.75, 1) showed a systematicchange in the susceptibility to radiation-induced amorphizationwith increasing Zr content. Gd_2Ti_2O_7 amorphized at relativelylow dose (0.2 displacement per atom at room temperature), andthe critical temperature for amorphization was 1100 K. Withincreasing zirconium content, the pyrochlores became increasinglyradiation resistant, as demonstrated by the increasing dose anddecreasing critical temperature for amorphization. Pyrochloreshighly-enriched in Zr (Gd_2Zr_2O_7, Gd_2Zr_1.8Mg_0.1O_6.85,Gd_1.9Sr_0.1Zr_1.9Mg_0.1O_6.85), and Gd_1.9Sr_0.1Zr_1.8Mg_0.2O_6.75) could not be amorphized, even attemperature as low as 25 K.