The microstructure, mechanical properties, and corrosion state of fuel rod claddings made of zirconium alloys of various compositions, which operated as part of fuel assemblies of various designs in VVER-1000 reactors to fuel burnup from ~20 to ~64 (MW day)/kgU, are studied. Some of them are tested in electrically heated units under conditions modeling dry storage. The influence of a temperature–time action on the fuel rods and the accompanying stresses in the claddings on their microstructure, state of an oxide film, and mechanical properties is analyzed. A relationship is revealed between the change in the mechanical properties of the claddings under the influence of thermal tests and the change in the microstructure of the cladding material.
Volkova et al. (Sat,) studied this question.