STUDY OF THE INFLUENCE OF RADIATION-INDUCED DAMAGE ACCUMULATION DURING THE INTERACTION OF HEAVY Xe22+ IONS ON CHANGES IN THE THERMOPHYSICAL PARAMETERS OF ZIRCONIA CERAMICS

Abstract

The aim of this paper is to evaluate the influence of the processes of radiation-induced damage formation in the form of point defects, dislocations and vacancies, as well as their accumulation and the formation of locally disordered regions in the near-surface layer of zirconia ceramics under irradiation with heavy Xe22+ ions with an energy of 230 MeV, on the change in the thermophysical properties of ceramics. The choice of the ion type for irradiation is due to the possibilities of modeling radiation damage processes comparable to the impact of uranium nuclei fission fragments during nuclear reactions in nuclear fuel. The choice of materials for irradiation in the form of ZrO2 ceramics is due to the prospects for their use as the main material for inert matrices of dispersed nuclear fuel for new generation reactors. This choice is due to the physicochemical, thermophysical and strength properties of ZrO2 ceramics, which are more resistant than other types of oxide ceramics. During research, it was found that the formation of isolated locally heterogeneous regions at low irradiation fluences does not lead to significant changes in the thermophysical properties of the damaged ceramic layer. However, polymorphic transformations of the t-ZrO2 → c-ZrO2 type, which occur at irradiation fluences above 1012 ion/cm2 , lead to a decrease in thermal conductivity and the appearance of heat losses associated with the disruption of the phonon heat transfer mechanisms in the damaged layer.