Structural Reliability Improvement Using In-Service Inspection for Intergranular Stress Corrosion of Large Stainless Steel Piping

Abstract

This paper describes probabilistic calculations that address Intergranular Stress Corrosion Cracking (IGSCC) of large stainless steel piping, a degradation mechanism of major concern to nuclear pressure boundary integrity. The first objective was to simulate the cracking of stainless steel piping under IGSCC conditions using the general methodology rec¬ommended in the modified computer program Piping Reliability Analysis Including Seismic Events (pc-PRAISE), and to characterize IGSCC by a single damage parameter (Dσ). This parameter, depends on residual stresses, environment conditions, and degree of sensitization. The second objective is to evaluate the structural reliability using remedial actions for IGSCC which are limited to benefits of in-service inspections and to identify the most effective approaches to improving piping reliability.