Overview and background of the RSE-M/RCC-MRx appendixes devoted to Fracture Mechanics Assessment at both design and operation level

摘要

A large effort was initiated in France 20 years ago in order to develop, validate and then codify analytical schemes for Fracture Mechanics Assessment (FMA) of nuclear components and piping systems. At the origin, this work was pushed by the need to define specific analyses rules, material behaviour, acceptance criteria... more generally all the necessary information needed for the assessment of defects detected during In-Service-Inspection or periodic safety re-evaluation. The target (analytical tool development) is a direct consequence of the need to perform quick and accurate evaluations for defects detected in service. But regarding the problematic of design with a large number of loading situations and the large number of potential defects to consider in the Defence-In-Depth demonstration, those appendixes have rapidly become the reference solution for FMA of PWR, at both design and operation level. This article gives an overview of those appendixes devoted to FMA, with a particular focus on the analytical J formulation (called J_s) for which a huge compendium of formulae specifically devoted to K and J fracture mechanics parameters calculation is provided. Within that frame, an overview of the formulations developed and their background (including the validation and codification strategy) is proposed. Finally a highlight of the on-going R&D devoted to EPR~™ needs is presented.