Roadmap For Repair of Buried Pipe

The repair of a corroded, damaged, or leaking buried pipe should be approached in a well-structured manner. Here is a roadmap to the repair options for buried steel pipes, with the corresponding brief commentary. 1. Open trench repair 1.1 New line, replacing the existing line (or segment). Determine whether to use the same material, or […]

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When Should the Rules for Severe Cyclic Conditions (Service) in ASME B31.3 Be Used?

This posting (November 2019) is an update to an October 2013 post which reflects changes to the ASME B31.3 Code relative to severe cyclic service that have occurred since the original post. There has been a fair amount of confusion as to when the rules for severe cyclic conditions in ASME B31.3 should be used, […]

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Operability And Fitness-for-Service (FFS) Of ASME Equipment In Nuclear Power Plants

Bringing Order and Logic to the Evaluation Process There is a multitude of documents and reports that describe the damage mechanisms of ASME pressure equipment (vessels, pumps, valves, piping, and tanks, and their supports) in nuclear power plants. Thousands of pages published by EPRI, the NRC, ASME, NACE, research laboratories, utilities, contractors, and others, to […]

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CFD Modeling of a Mixing Tee – Part 1: Model Validation

by Dave Dewees, Zumao Chen and L. Magnus Gustafsson This 2-part blog deals with CFD modeling of a mixing tee that is often found in industry. Traditional simulation is validated against experiment, as well as a new commercially available method that offers the possibility of substantial solution time reduction.  In fact, the new method is shown […]

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CFD Modeling of a Mixing Tee – Part 2: Predictions of Temperature Fluctuations

by Dave Dewees, Zumao Chen and L. Magnus Gustafsson Miss Part 1? Click Here This is the second part of a 2-part blog.  In Part 1, the stress-blended eddy simulation (SBES) and large eddy simulation (LES) approaches for simulating turbulence have been validated against test data obtained from a mixing tee. In this part, the […]

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Why do Clamped Connections With Metallic Seals Sometimes Leak?

Clamp connections with metallic seals can offer superior joint integrity over traditional flanged connections but caution must be exercised regarding the service conditions, especially when cyclic thermal loading is present. This blog post highlights aspects of a clamp connection analysis performed by Becht Engineering. The client had observed significant loss of bolt preload at several […]

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Pipe Fabrication Dimensional Errors — I Can’t See You!!!

Can a level, square and tape measure really measure up to today’s quality standards on complex spools? I was watching my baby girl cover her eyes as she had done something naughty. Doing this gave her the feeling that if she couldn’t see her mother or myself then she would not get into trouble. Despite […]

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Grade 91 Steel – How Did We Get Here? Part 1

This blog is the first part of a 3-blog series. To view the rest of the story click HERE for Part 2 and Here for Part 3. Part 1: History Thirty years ago, Grade 91 (9Cr-1Mo-V) steel was hailed as the savior of the power generation industry [1]; now it’s behavior has been described as […]

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Grade 91 Steel – How Did We Get Here? Part 2

Read Part 1 Part 2: Type IV Cracking and Inspectability The current concerns with Grade 91 are fundamentally and firmly rooted in inspectability of Type IV damage; while sensitivity of the material can be managed (see for example [1]), Type IV cracking is perhaps the Achilles heel of Grade 91.  At a high level, the […]

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Grade 91 Steel – How Did We Get Here? Part 3

Read Part 1 or Read Part 2 Part 3: Allowable Stresses While inspectability has been at the center of recent concerns, other issues such as chemistry control, ductility and excessive oxidation have also come under scrutiny.  Perhaps most interesting is that while all of the preceding concerns have been debated, it has also been found […]

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