[en] Results of mathematical simulation of major strains, occuring under the swelling of hollow cylindrical column of a fuel rod, placed into hard coating are presented. Strain-stress state of fissile material, its free swelling being described in terms of spheric gas pore model, is considered on the basis of the finite strain theory. A system of ordinary differential equations is derived, describing considerable form change of the internal hollow of cylinder out of fissile material under its constrained swelling in hard coating. Results of numeric integration and analytical solution of the derived differential equations for a wide spectrum of the model parameter values are presented