Crack growth resistance of low alloy steel in high temperature oxygenated water

Crack growth rates for Low Alloy Steel in high temperature, high purity oxygenated water were studied under cyclic loading conditions. Both fracture mechanics and simulated reactor pressure vessel nozzle test specimens were utilized. Cycle frequency, mean stress, and coolant oxygen content were studied. The role of crack face oxidation in mitigating crack growth rates was identified. The overall data band is similar to that reported in the literature for Pressurized Water Reactor conditions. The overall impact of the study is that disposition of indications potentially found by future in-service inspections can be made with improved confidence since the resistance to crack extension is quite high