Study on analysis of crystal structure in CeO2 doped with Er2O3 or Gd2O3

Abstract To simulate the effects of burnable poison doping in nuclear fuel UO 2 , Er 2 O 3 (or Gd 2 O 3 )-doped CeO 2 pellets were prepared. Changes in lattice constant and atomic disordering for CeO 2 due to the Er 2 O 3 and Gd 2 O 3 doping were measured by means of XRD and XAFS. By the Er 2 O 3 doping, the lattice constant decreased, and a disordering of lattice structure was induced in the samples. The doping with Er 2 O 3 also induced the disordering of atomic arrangement around Er atoms, which was observed through the change in XAFS spectra. In contrast, the effect of Gd 2 O 3 doping was smaller than that of Er 2 O 3 doping. The result was discussed in terms of ionic size of dopants in CeO 2 crystal.