Environmental effects on the reliability of an AISI 304 structure

Racim Boutelidja,Bachir Merzoug,Mohammed Amine Belyamna,Abdelmoumene Guedri

doi:10.3221/igf-esis.50.10

Abstract

This work is based on the application of probabilistic fracture mechanics (MRP) models to predict the reliability of pressure pipelines in nuclear power reactors. The simulation of cracking of stainless steel piping under the conditions of intergranular stress corrosion cracking (IGSCC) is based on the improved modified piping reliability analysis including seismic events (PRAISE) code. The IGSCC is characterized by a unique damage parameter that depends on residual stresses and environmental conditions. Case studies of IGSCC failures in nuclear power plants are presented and the contribution of environmental effects on crack initiation and leakage is discussed. For small damages we observed that the change in temperature or oxygen concentration does not affect the initiation process but their decrease contribute favourably to the decrease in the leakage probabilities.

Highlights

Damage detection and quantification mean knowing when and where it initiates; determining its propagation mode(s) and its interactions with the microstructure
The intergranular stress corrosion cracking (IGSCC) is characterized by a unique damage parameter that depends on residual stresses and environmental conditions
TExample he application problem illustrates the use of M-piping reliability analysis including seismic events (PRAISE) to simulate the initiation and the growth of cracks in a welding due to the stress corrosion cracking mechanism

Summary

Introduction

Damage detection and quantification mean knowing when and where it initiates; determining its propagation mode(s) and its interactions with the microstructure. It leads us to the understanding, modelling, and prediction of environmentally assisted cracking processes, i.e., stress corrosion, fatigue-corrosion, and hydrogen embrittling. It is, possible to evaluate the respective role of the different chemical, mechanical, and metallurgical intervening parameters, and necessary steps to establish phenomenological models. Stress corrosion cracking (SCC) is one of the important mechanisms in the degradation of steels. This mechanism induces material cracking due to a combined action of a sensitive material, a tensile stress, and corrosive environment (see Fig. 1). In the piping of a boiling water reactor, the sensitive material in the vicinity of welds is the stainless steel AISI 304

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Conclusion