— The characteristics of the production technology for fuel rod cladding oriented to its application for water-moderated water-cooled power reactors with a coolant temperature of 300−350°C are presented. Possible directions for the modification of the cladding surface are proposed. The methodological background for the diagnostics of materials based on the ion-beam and X-ray diagnostic methods is discussed. Using this diagnostics, it is possible to characterize the parameters of the inner and outer surfaces of the fuel-rod cladding without changing its form. Experimental data are presented, which demonstrate the efficiency of the proposed analytical complex for characterizing the surface layers of fuel-rod cladding.