COPRIN

This project aims at developing models for environment-assisted cracking of Ni-base alloys and austenitic stainless steels. The main objective is to improve the physical Stress-Corrosion Cracking models applied to materials and, to a lesser extend, forged or rolled components. The goals of the project are:

• To carry out parametric studies in PWR primary water in order to evaluate the effect of water chemistry, material manufacturing and loading on the susceptibility to initiation and propagation of environmental assisted cracking (EAC).
  
• To improve existing empirical models prediction the time to initiation and the crack growth, considering as physical parameters as possible
  
• To understand underlying mechanisms in terms of deformation, oxidation, and their interactions
  
• To develop physical-based models of EAC allowing long term predictions.
  

Recently, significant progress has been made with respect to the evaluation of the crack growth rates of intergranular stress corrosion cracking in rolled plates (representative of steam generator divider plates) and bars in alloy 600. Among others, significant crack growth rates were observed on several plates after prior deformation (e > 0.07). Propagation laws are proposed, as a function of pre-straining (e), for three heats of rolled plates.