1. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Predicting the Probability Of Failure of Gas Pipelines Including Inspection and Repair Procedures L.Zhang, R.Adey Computational Mechanics International San Sebastian 12.09.2007

2. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Contents 1.Why Probability of Failure (POF) analysis 2.An introduction to the POF calculation method 3.Overview of POF calculation tool- PipeSafety developed for NATURALHY project 4.A sample problem 5.Summary

3. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Probability Of Failure  What is Probability of Failure?  A number which indicates the probability that a pipeline could fail within a given timeframe  Failure criterion: leakage including breakage (zero tolerance to gas/hydrogen leakage)  The Probability of Failure can be used to assess the impact on the safety of a pipeline of changes in the design and management and the type of gas carried by the pipeline  The POF also provides a link to economics type models

4. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD)  The POF can include the impact on the pipeline safety of:  The type of gas being carried and its impact on the materials or defects present in the pipeline  The operational loads on the pipeline  The inspection strategy and the performance of the inspection tools  The repair strategy  The quality of the pipeline e.g. The number and type of defects present Probability Of Failure

5. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Hydrogen  Hydrogen has been shown to change the behaviour of materials subject to low cycle fatigue loads  These changes are associated with plastic deformation of the material  Hydrogen is therefore expected to change the behaviour of sharp crack like defects  The POF calculation is therefore focused on crack-like defects

6. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Probability Of Failure  A probabilistic fracture mechanics approach has been used to determine the behaviour of crack like defects  There are three main ways of obtaining the POF  Analytical solution  First/Second Order Reliability Method (FORM)  Monte-Carlo simulation with/without variance reduction technique

7. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Calculation Method  The current failure criteria used in the model is based on BS7910 level 2 FAD  Other failure models could be added to the POF tool

8. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Calculation Method  Monte-Carlo simulation

9. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Calculation Method

10. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Calculation Method  All the inputs into the model can be expressed probabilistically  Defect distribution, material behaviour etc.  Common probability density functions  Lognormal distribution  Weibull distribution  Exponential distribution, normal distribution…etc.

11. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Calculation Method  The POF of a whole pipeline can be calculated as follows:

12. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Calculation Tool PipeSafety 1)Main page

13. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 2)Pipe geometry POF Calculation Tool PipeSafety

14. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 3)Defect definitions POF Calculation Tool PipeSafety

15. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 4)Loads definitions POF Calculation Tool PipeSafety

16. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 5)Residual stresses POF Calculation Tool PipeSafety

17. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 6)Material properties POF Calculation Tool PipeSafety Data is being obtained by experimental testing as part of the NATURALHY project

18. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 7)Inspection tool characteristics POF Calculation Tool PipeSafety

19. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 8)Repair procedure POF Calculation Tool PipeSafety

20. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) 9)Analysis and other options POF Calculation Tool PipeSafety

21. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Sample Application Basic input data

22. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Basic unit (mm,MPa) Cracks in Natural Gas Cracks in 100% hydrogen c 5.2e-132.4e-14 m 33.8 Fatigue crack growth data from TNO, Netherlands for natural gas and 100% hydrogen Sample Application

23. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) X52 Base Material In 100% Natural Gas  Repair criteria  Pre-inspected and then inspected at every 10 years  If a detected crack will lead to failure in 12 years it is repaired  A pipeline with 10 cracks/km  Fracture and fatigue properties  c=5.2e-13  m=3  K IC =4743.416MPa*mm 1/2  Result  Cumulative POF of a single defect (60 years): 3.0e-5  Total POF: 3.0e-4 per km

24. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Of A Defect Base Metal

25. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Of A Defect in welds

26. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Improve Inspection What happens if we improve the sensitivity of the inspection tool? New inspection tool Probability of Detection Curve

27. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) POF Of A Defect Base Metal Higher sensitivity of inspection tool reduces the POF

28. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Summary  Probability of Failure analysis enables the impact of hydrogen on the safety of pipelines to be assessed  The analysis does not only consider the impact of hydrogen on the micro mechanical behaviour of the materials but also the way the pipeline is managed  Inspection strategy  Repair strategy  Operational loads

29. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) Summary  It can be used as a sensitivity tool to assess management options and can link to more economic models  The initial crack size distribution is an important input parameter and further work is required to validate this and other data  Material properties such as crack growth threshold value, fatigue properties and toughness are key parameters

30. Preparing for the Hydrogen Economy by Using the Existing Natural Gas System as a Catalyst // Project Contract No.: SES6/CT/2004/502661 NATURALHY is an Integrated Project funded by the European Commission’s Sixth Framework Programme (2002-2006) for research, technological development and demonstration (RTD) The End Question time