Session: MF-12-01 Materials and Fabrication: General Topics I

Paper Number: 62936

Start Time: Wednesday, July 14, 2021, 05:00 PM

62936 - Further Development of Probabilistic Leak-Before-Break Methods 

Leak-before-Break software has been developed to provide probabilities of detecting a leak from a circumferential crack in a pipe.  This utilises the methods detailed in the UK structural integrity assessment procedure, R6, and was presented in PVP2020-21769.  The latest developments in this code are presented in this paper and account for initial surface defects that can develop over time to become through wall cracks.  This is possible through the implementation of stress intensity factor solutions for semi-elliptical circumferential flaws in cylinders of Chapuliot et. al and crack growth laws due to Stress Corrosion Cracking.

The results presented in this paper demonstrates the functionality of the code with sample problems that are designed to be plant representative.  Probability of detection is also accounted for and enables reliabilities to be calculated based on probability of failure from the Monte Carlo simulations.

The impact of weld residual stresses (WRS) on Crack Opening Displacement is an important factor in LbB assessments and methods to assess this are discussed in the paper along with the results of simulations.

The development of this software was done in collaboration with the European project ATLAS+ which has a work package dedicated to comparing probabilistic leak before break assessment tools.

Presenting Author: Peter Gill Jacobs

Authors:

Peter Gill Jacobs
Brian Daniels Jacobs