Irradiation porosity was investigated with scanning electron microscopy equipped with back scattered electron (BSE) detector through the thickness of the cladding manufactured of austenitic stainless steel 16Cr-19Ni-2Mo-2Mn-Nb-Ti-V-P-B. Investigated sample of the cladding was operated at temperature around 480 °C up to damage dose of 87 dpa. Gradient of temperature through the cladding thickness leads to decrease of average size and increase of concentration of voids from inner to outer surface.Average swelling in middle layers of the cladding is 0,5%. In areas near inner and outer surface of the cladding inhomogeneity of irradiation porosity is observed. It is shown that local inhomogeneity of irradiation porosity depends onstructure of the cladding metal, notably on density of microtwins and areas with high dislocation concentration.