Becht Engineering provides expert consulting services to the process and power industries, worldwide. We have specialists in most of the relevant engineering and project disciplines.

We are growing rapidly, with an extensive base of repeat clients. We have a reputation for getting the job done right.

Fitness-for-Service of Corroded Buried Pipes

When planning or performing a wall thickness inspection of buried pipe, it is necessary to establish the procedure to be used in evaluating the thickness readings, and determine the pipe’s fitness-for-service (FFS), which will be the basis of run-or-repair decisions.

We are currently working with EPRI to develop such a procedure. This article is intended to provide a broad brush of the FFS process for buried pipe.

An industry that has come to grips with this process for over 30 years is the oil and gas pipeline industry. They use ASME B31G to assess the integrity of corroded pipelines. The ASME B31G procedure is simple, conservative, and … not applicable to nuclear plant buried pipes. The reason is that B31G contains assumptions regarding the operating loads, the operating pressure stress, and the equivalency to a hydrotest which are not applicable to ASME B31.1 or ASME III lines.

Another reference would be ASME XI Code Case N-597 and API 579 / ASME FFS-1, for safety-related and non-safety related pipes respectively. But neither document explicitly addresses buried pipes. 

For a PDF of our Becht Nuclear Summer 2011 Newsletter,
please click here.

To view past copies of the Becht Nuclear Newsletters, please click here.

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Seismic Design and Retrofit of Essential Systems in Nuclear Power Plants by Mr. George Antaki, Becht Engineering Company, and Dr. Jim Johnson, Consulting Engineer

1. Seismic Regulatory Requirements for Nuclear Power Plants.

In the United States nuclear power plants are, by regulation, designed to address these three damage mechanisms. The hierarchy of regulatory requirements starts with the Code of Federal Regulations 10CFR50. Appendix A of 10CFR50 imposes a general Design Criterion entitled GDC 2, “Design Bases for Protection Against Natural Phenomena,” in which the US Nuclear Regulatory Commission (NRC) requires that nuclear power plant structures, systems, and components (SSCs) important to safety be designed to withstand the effects of earthquakes without loss of capability to perform their safety functions.

In broad terms, the three critical functions that have to be maintained after a large earthquake are: