Comparison of J-parameters of cold worked and stress relieved Zr-2.5Nb pressure tube alloy determined using load normalization and direct current potential drop technique

摘要

The fracture toughness of Zr-2.5Nb pressure tube alloy used in Indian Pressurized Heavy Water Reactor was determined in the temperature range of 30-300 °C using load normal ization technique (LNT) and a comparison between the crack initiation and the crack prop agation toughness parameters is presented with the values obtained using direct current potential drop (DCPD) technique. The dependence of error in J-parameters determined using LNT to that obtained using DCPD on temperature and final crack extensions was also investigated. Below 200 °C, the error exhibited weak dependence on final crack extensions. Above 200 °C the error in initiation toughness increased significantly while the error in propagation toughness was practically unaffected.