Quantification of 1.75 MeV Xe5+ induced defects in zirconia doped ceria (Ce0.8Zr0.2O2)

This study investigates the structural stability of the CeO2-ZrO2 system when subjected to high doses of irradiation (a few hundred displacements per atom). The goal is to explore their potential use in safe immobilization of spent nuclear fuel and development of accident-tolerant fuels for next-generation nuclear reactors. Highly dense pellets were synthesized using a solid-state reaction and then irradiated with 1.75 MeV Xe5+ ions at ion fluences ranging from 1 x 10(15) to 1 x 10(17) ions/cm(2). Structural and microstructural analyses were conducted using glancing angle x-ray diffraction, micro-Raman spectroscopy, and scanning electron microscopy. The results indicate that Ce0.8Zr0.2O2 has a high tolerance against irradiation-induced phase transformation or amorphization but does generate irradiation-induced point defects. Each energetic ion produced a deformed region with a voluminous swelling of similar to 0.61 +/- 0.09 nm and a damaged zone of similar to 0.09 +/- 0.02 nm, as calculated from the irradiation-caused peak broadening that is explained by a three-step damage accumulation model. The electron microscopy studies show that grain boundaries serve as a sink for defects, and an increase in grain size was observed due to defect accumulation inside the grain's volume. Overall, the study shows that polycrystalline fluorite-structured Ce0.8Zr0.2O2 is a promising nuclear material for advanced energy systems as it did not show significant structural damage such as amorphization and grain fragmentation, even on irradiation at a high dose of similar to 428 dpa.

Automated summary

This study investigates the structural stability and defect generation of the CeO2-ZrO2 system under high doses of irradiation. The results show that Ce0.8Zr0.2O2 exhibits good radiation tolerance but still generates point defects. Grain boundaries play an important role in defect trapping, and grain size increases due to defect accumulation.