Three ODS steel claddings, one martensitic phase and two ferritic ones in initial structures, were neutron-irradiated in JOYO and their nano-meso structural evolutions during irradiations and ring-tensile behaviors were evaluated at conditions as close as possible to those encountered in-service. For the structural features, no significant macro scale structural changes, such as grain morphology and dislocation structures, were recognizable, but nano scale changes, such as carbide and oxide dispersoids, emerged in all neutron-irradiated ODS claddings. With respect to the ring-tensile properties, on the other hand, a manifested variation of irradiation temperature dependence among all the ODS claddings was revealed, reflecting the individual microstructural evolution of ODS steel claddings during neutron irradiation.