Reliability based inspection of nickel-based alloy welds in boiling water reactor environment

Stress corrosion cracking (SCC) problems are routinely observed in boiling water reactor (BWR) units. Nickel-based alloy welds are commonly used in BWR units; the nickel content of the material improves resistance to stress corrosion cracking. However, stress corrosion cracking is still a problem for these welds. When a crack is detected, a decision whether an immediate repair in needed has to be made. A model for estimating reliability of BWR nickel-based alloys welds subjected to SCC using non-destructive inspection techniques is introduced. The proposed methodology and model has been illustrated through a numerical example to estimate the required re-inspection interval in order to keep the target reliability level.