Microstructure evolution in 200-MeV Xe ion irradiated CeO2 doped with Gd2O3

Abstract

The microstructure of virgin and heavy ion-irradiated Ce1–xGdxO2–x/2 with a wide range of Gd dopant concentrations (0 ≤ xGd ≤ 0.5) was evaluated by x-ray diffraction (XRD), micro-Raman spectroscopy, and transmission electron microscopy (TEM) for selected area electron diffraction (SAED) analysis and plane-view bright-field (BF) imaging of ion tracks. The Ce1–xGdxO2–x/2 samples were irradiated with 200-MeV Xe14+ ions up to fluences from 3 × 1011 to 1 × 1013 cm−2 at ambient temperature. XRD patterns of the virgin Ce1–xGdxO2–x/2 samples showed saturation of lattice parameter and relaxation of microstrain in Ce1–xGdxO2–x/2 which are attributed to the increasing Gd concentration. Moreover, micro-Raman spectroscopy and SAED patterns revealed the bixbyite (C-type) structure formation and oxygen vacancy ordering for xGd > 0.2 that is induced by dispersed C-type domains in the fluorite-structured (F-type) matrix. In the irradiated samples, asymmetric XRD peaks induced by lattice distortion were observed together with ion tracks in BF-TEM images. The radiation damage was recovered with the increase of Gd concentration. There is a rapid reduction of radiation damage cross section for xGd > 0.2 with a reduction of the C-type structure reflections in XRD and SAED patterns.

Study of the Influence of Doping Efficiency of CeO2 Ceramics with a Stabilizing Additive Y2O3 on Changes in the Strength and Thermophysical Parameters of Ceramics under High-Temperature Irradiation with Heavy Ions

“…This helps to increase the safety of nuclear fuel, since the matrix helps prevent diffusion of radioactive products and heat release into the environment. Ceramic inert matrices based on cerium dioxide can be especially useful in this case, since they are highly resistant to radiation damage and chemical corrosion, which makes them attractive for use under conditions of extreme radiation exposure in nuclear reactors, including irradiation with heavy ions akin to fission fragments [19][20][21][22].…”