Comparison of the Waste Transmutation Potential of Different Innovative Dedicated Systems and Impact on the Fuel Cycle

Study of Radiation-Induced Damage Processes in CeZrO4-YZrO3 Ceramics Caused by Helium Irradiation

Composite oxide ceramics CeZrO₄-YZrO₃ obtained by mechanochemical synthesis were chosen as objects of study. The most dangerous type of radiation defect in structural materials is associated with helium accumulation in the structure of the near-surface layer. This can lead to the destruction and swelling of the material, resulting in a decrease in its strength and thermal characteristics. During the studies, it was found that the most significant structural changes (deformation of the crystal lattice, the magnitude of microdistortions of the crystal lattice) are observed with irradiation fluence above 5×10¹⁶ ion/cm², while the nature of the changes is exponential. X-ray diffraction analysis found that the nature of the crystal structure deformation has a pronounced type of stretching due to the accumulation of implanted helium and its subsequent agglomeration. A comparative analysis with data on microdistortions of the crystal lattice and the values of microhardness and softening of ZrO₂ and CeO₂ showed that two-phase ceramics of the cubic type CeZrO₄-YZrO₃ are more resistant to radiation-induced degradation than single-phase ZrO₂ and CeO₂. Results of strength and thermophysical characteristics showed that the presence of two phases increases resistance to destruction and disorder, leading to a decrease in strength and thermal conductivity.