Study of cerium solubility in Gd2Zr2O7 by DFT+U calculations

Abstract The pyrochlore Gd 2 Zr 2 O 7 has been proposed as a favorable structure for the immobilization of actinide nuclear waste, due to its high radiation resistance. Because CeO 2 exhibits similar properties and radiation response to many actinide dioxides, it is often used as a surrogate for actinide dioxides in both experimental and computational studies. In the present work, we investigate the solubility of Ce in Gd 2 Zr 2 O 7 , as well as the energetic and electronic properties of Gd 2− y Ce y Zr 2 O 7 , based on density functional theory plus Hubbard U correction (DFT + U). Our calculations show that Gd 2 Zr 2 O 7 and Ce 2 Zr 2 O 7 form a solid solution over the entire range of Ce content, in excellent agreement with experiments. The increased stability of the ordered pyrochlore structure with increasing Ce content may affect radiation resistance.