[en] It is proposed the approach for estimating the impact of thin protective coatings on the stress–strain state of the thick–walled claddings of cylindrical fuel rods considering internal and external pressures from fission products and moving heat carrier in a nuclear reactor core. This approach is used for quantitative estimations the impact of possible thin coatings made from a stainless steel on the stress–strain state of the cladding made from the Zirconium–based alloy used in the WWER–1000 nuclear reactors. It is shown that thin protective coatings can allow increasing the general strength and reliability of the cladding due to stresses decreasing. (author)