PWR Effect On Crack Initiation Under Equi-biaxial Loading

Cédric Gourdin,Hager Dhahri,Habibou Matirouman,Grégory Perez,Stéphan Courtin,Jean-Christophe Le Roux,G Hénaff

doi:10.1051/matecconf/201816516005

Abstract

The lifetime extension of the nuclear power stations is considered as an energy challenge worldwide. That is why, the risk analysis and the study of various effects of different factors that could potentially prevent safe long term operation are necessary. These structures, often of great dimensions, are subjected during their life to complex loading combining varying mechanical loads, multiaxial, with nonzero mean values associated with temperature fluctuations and also PWR environment. Based on more recent fatigue data (including tests at 300°C in air and PWR environment, etc…), some international codes (RCC-M, ASME and others) have proposed and suggested a modification of the austenitic stainless steels fatigue curve combined with a calculation of an environmental penalty factor, namely Fen, which has to be multiplied by the usual fatigue usage factor. The aim of this paper is to present a new device "FABIME2E" developed in the LISN in collaboration with EDF and AREVA. These new tests allow quantifying the effect of PWR environment on disk specimen. This new device combines the structural effect like equi-biaxiality and mean strain and the environmental penalty effect with the use of PWR environment during the fatigue tests.

Highlights

The question of assessing the margins and safety factors in the fatigue analyses which are widely used today (ASME BPV III, RCC-M, JSME, EN-13445-3, etc... [14]) is a very challenging one
Based on more recent fatigue data, some international codes (RCC-M, ASME and others) have proposed and suggested a modification of the austenitic stainless steels fatigue curve combined with a calculation of an environmental penalty factor, namely Fen, which has to be multiplied by the usual fatigue usage factor
This paper is focusing on the description of two kinds of experimental devices to perform fatigue tests on specimen with or without the effect of pressurized water reactors (PWR) environment

Summary

Introduction

The question of assessing the margins and safety factors in the fatigue analyses which are widely used today (ASME BPV III, RCC-M, JSME, EN-13445-3, etc... [14]) is a very challenging one. The testing is in practice conducted on small laboratory specimens, which triggers the question of how to extrapolate results to a full size component Another difficulty is that the rules need to remain easy to apply in order to be applied for industrial engineering calculations. Based on more recent fatigue data (including tests at 300°C in air and PWR environment, etc...), some international codes (RCC-M, ASME and others) have proposed and suggested a modification of the austenitic stainless steels fatigue curve combined with a calculation of an environmental penalty factor, namely Fen, which has to be multiplied by the usual fatigue usage factor. A second and new device named FABIME2e and based on the first device, is for the study of the impact of the environmental effects

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Conclusion