Model Modules to Assist Assessing and Controlling Stress Corrosion Cracking (SCC)

Main Objective

Validation of the newly available direct assessment methodologies for both external corrosion and stress-corrosion cracking; development of improved modules for assisting operators with controlling the parameters that cause stress-corrosion cracking; approaches for improving the integrity of systems with wrinklebends and buckles; and a viable approach to running fracture that should help operators minimize its consequences when ruptures occur.
Goals:
(1) Develop and validate a mechanism for near neutral stress corrosion cracking (NNSCC) that reflects operational and right-of-way scenarios typical of US pipelines;
(2) Quantify field characteristics in terms of cracking colonies and pipeline operation for line pipe from X52 thru X65;
(3) Establish hydrostatic retest protocols to assist in controlling high pH SCC in terms of pipeline operation represented by compressor discharge pressure and temperature for line pipe from X52 thru X65;
(4) Package the high pH SCC model in user-friendly format, including graphical-user interface to provide output indicative of integrity implications related to hydrostatic retesting; and
(5) Quantify hydrogen evolution and establish relationships between hydrogen and evolution of microplastic strain, as basis to establish related kinetics for NNpHHSCC.
This is a consolidated project with Project No 162, Project No 164, and Project No 165.

Public Abstract

The Pipeline and Hazardous Materials Safety Administration is keenly interested in ensuring the safety of the nation's pipeline infrastructure. Battelle proposes a broad program that addresses several key elements of the complex but related issues that impact pipeline integrity to help meet this need. It is known that external and internal corrosion of buried pipelines receives much attention from operators. Stress-corrosion cracking and external corrosion have been implicated in several field failures. Consequently, Battelle has invested considerable effort to both understand and mitigate future related failures. We have also focused on other mechanisms that undermine integrity of vintage systems such as wrinklebends. Finally, ruptures occur occasionally when preventive measures taken to optimize pipeline integrity fail. In the worst of those cases, rupture propagates rapidly along the pipeline ("running fracture"), whose length controls the consequences of failure. Our proposal combines these elements into one project to provide higher value-added to the Government. Battelle's program comprises five projects previously submitted as separate white papers combined within the task structure of one program. The scope includes: validation of the newly available direct assessment methodologies for both external corrosion and stress-corrosion cracking; development of improved modules for assisting operators with controlling the parameters that cause stress-corrosion cracking; approaches for improving the integrity of systems with wrinklebends and buckles; and a viable approach to running fracture that should help operators minimize its consequences when ruptures occur.