Iodine Stress Corrosion Cracking of Unirradiated Zircaloy-2 Tubing by Means of Ring Tension Test

Abstract

Ring tension testing methods were applied for studying the iodine stress corrosion cracking (SCC) behavior of unirradiated cold-worked (CW) and recrystallized (RX) Zircaloy-2 tubing at 300°C. Two kinds of tests—constant load and constant cross-head speed—were conducted on the grooved ring tension specimen simulating a plane-strain stress state under uniaxial loading, as well as on the simple ring tension specimen. The results showed that SCC failure threshold stresses were approximately 450 and 300 MPa, respectively, for the grooved CW and RX specimens. The ratio between the threshold stress of the grooved specimen and the yield stress derived from the simple specimen is equal to 1.4 for both CW and RX materials. The threshold value of the grooved RX specimen is 1.3 times larger than found on the same material of simple shape, which corresponds to the yield stress ratio between the grooved and simple specimens. Inside surface observations of specimens stressed in iodine environment suggested that corrosio...