“…Interest in ZrO 2 ceramics is also due to the fact that, when used as materials for fuel assemblies (FAs), ceramics create an additional protective barrier for oxygen and hydrogen penetration from the coolant, thereby reducing the rate of FA degradation. However, a number of studies show that in ZrO 2 ceramics, under the action of irradiation with heavy ions of Kr, Xe at high irradiation fluences, polymorphic transformations of the t-ZrO 2 → c-ZrO 2 type occur, caused by the processes of radiation damage [21][22][23]. Such transformations can have a negative impact on resistance to degradation, hydrogen absorption, and swelling of ceramics as a result of long-term operation.…”