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. 

Becht Engineering Staff’s Nuclear Rigging Experience Dates Back to 1975

PWR Construction… Unloaded from barges, transported, upended and Installed Combustion Engineering and Westinghouse Reactor Pressure Vessels and Steam Generators through the equipment hatch utilizing the polar crane girders and jacking systems and over the top of containment utilizing mobile lift cranes. Installed pressurizer vessels and reactor heads utilizing the polar crane and mobile lift cranes. Installed ground assembled Polar cranes and containment dome liners. Installed body and bearing beams, turbines, stators, diesel generators and moisture separator re-heaters in the turbine buildings. Transported, skidded and set main transformers. (SONGS 2 & 3, WPPS Hanford 1, 3 and Satsop 4 & 5, KO-RI 2 and Vogtle 1 & 2)