Investigation of the crack growth rate in the Zr-1%Nb claddings under iodine stress-corrosion cracking

Analysis of results of experimental investigations of crack growth in conditions of stress-corrosion cracking of fuel element claddings from the Zr-1%Nb alloy is presented. The investigations were performed for tubular samples of the claddings at 350 deg C. As an initial defect was used a fatigue crack at the inner surface of a sample. The dependence of the crack growth rate on the stress intensity factor is obtained. The threshold stress intensity factor is determined too. Its value is 4.8 MPamult m exp 1/2 .