A FRENCH GUIDELINE FOR DEFECT ASSESSMENT AND LEAK BEFORE BREAK ANALYSIS

A large program was launched in France in order to develop defect asse ssment procedures and leak-before-break methods (LBB) applicable for t he design and for operating FBR plants. As a result of the collaborati on between CEA, EdF and Novatome, a French guideline A16 has been prod uced as a first step in order to produce further documents in RCC-MR f or design and for in-service inspection. This paper presents the main items developed in this guide considering low and high temperature: fa tigue or creep-fatigue crack initiation based on the sigma(d) approach calculating stress and strain at a distance d=50 mu m from the crack tip, fatigue crack growth based on da/dN-Delta K-eff relationship with a Delta K-eff derived from a simplified estimation of Delta J by refe rence stress, creep-fatigue crack growth adding the fatigue crack grow th and the creep crack growth during the hold time derived from a simp lified evaluation of C, ductile tearing based on simplified estimatio n of J (reference stress method) and plastic collapse of the ligament with and without holdtime, leak-before-break procedure. Some detailed examples explaining the use of this A16 guide are presented.