Theoretical Simulation of the Quasistationary Crack Growth in Zirconium Claddings in an Iodine Atmosphere under Stress

A computational-theoretical model of quasistationary growth of corrosion cracks in zirconium claddings under stress in an iodine atmosphere is developed. The model takes into account the nonuniformity of the behavior of the material on the crack front as a result of the anisotropy of zirconium properties and the cladding texture. The crack growth rate is determined by the iodine flux into the tip in brittle regions, and the flux depends on the stress distribution between the brittle and viscous regions. Iodine diffusion in the gas phase and along the surface are taken into account in the calculation of the iodine flux into the crack tip. The influence of irradiation and texture on crack growth is studied. The computed growth rate of corrosion cracks is in agreement with the experimental data.