Simulation of Initiation and Development of Corrosion Cracks in Zirconium Fuel Claddings Under Conditions of Stress Corrosion Cracking in Environment of Iodine

The process models of iodine corrosion cracking of zirconium fuel claddings, used to calculate the durability of the cladding (time for loss of tightness) are considered. A method for determining the corrosion crack propagation rate in claddings made of E110 alloy Ø 9.1 × 0.65 mm and the results of corresponding studies (estimation of corrosion crack propagation rate and stress intensity factor K_ISCC) are given at a temperature of 380 °C in iodine environment at a concentration of ~ 0.2 mg/cm². Studies were performed using tubular samples with a fatigue crack. A fatigue crack on the inner surface of cladding made of E110 Ø 9.1 × 0.65 mm alloy is the initiator of a corrosion crack emergence (nucleation). The results of corresponding studies are consistent with data from the literature. The proposed study of the corrosion cracking process of fuel claddings in accordance with the results of fracture mechanics is of practical importance for substantiation of the regulation of reactor operating conditions

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