Study on effects of energetic ion irradiation in Gd2O3-doped CeO2 by means of synchrotron radiation X-ray spectroscopy

To study the effects of Gd2O3-doping and the irradiation with high energy fission products in the nuclear fuels (UO2), Gd2O3-doped CeO2 pellets, which are simulation materials of UO2, were irradiated with 200 MeV Xe14+ ions. Effects of Gd2O3-doping and the ion irradiation were estimated by using Extended X-ray Absorption Fine Structure (EXAFS) measurement. The interatomic distances between each Ce and the first nearest O atoms, and Ce and the second nearest Ce atoms increase by the irradiation and the effect of the ion irradiation on the atomic distances is more pronounced for higher amounts of dopant. The Debye-Waller factors for Ce-O and Ce-Ce pairs increase with increasing the amount of Gd2O3 dopant. These results suggest that the lattice binding energy is weakened by Gd2O3-doping. The Debye-Waller factors increase also by the irradiation. The effect of ion irradiation on the Debye-Waller factors, however, becomes smaller for higher amounts of dopant.