Fabrication Uncertainty in B2 for Nuclear Pipe Bends Subjected to In Plane Opening Moment

Abstract

For reliabilitybased design of pipe bends and elbows, a probabilistic characterization of the primary stress indices (B1 and B2) is essential. This paper aims at the characterization of the fabrication/geometric uncertainty in B2, for thin stainless steel long radius pipe bends, subjected to inplane opening moment. This characterization is performed in a framework based on Monte Carlo simulation and nonlinear finite element analysis. A revision of the codebased expression for B2 is proposed where a random variable K replaces the constant numerator in this expression. The statistics for K are provided for different pipe nominal dimensions, which indicates that the existing provision gives a very conservative estimate of the plastic collapse moment for pipe bends subjected to inplane opening flexure.