Recently in Staniless Steel World magazine we published an article written by Steve Young about a project for the development of 3D and CT scanning technology.
The piping replacement project was carried out by Exact Metrology, a supplier of 3D laser and CT scanning equipment and services. Its new Leica HDS scanners were used on a piping project at a nuclear power generation station in Kansas. The project took 800 hours and involved scanning stainless steel piping in 20 rooms and the entire main level of containment with four operators, according to Dean Solberg, Co-president and Founder of Exact Metrology.
Identifying high points
The project began when R. Brooks Associates brought in Exact Metrology to digitally map out several critical pipe runs and identify all high points throughout the stainless steel piping system. Once all high points were identified, engineers could determine if additional venting for gas voiding was required. As a bonus, the data was also used to help validate and correct schematic drawings. When measuring and quantifying the piping systems and associated high points did not lend itself to conventional surveying measurements, Exact Metrology was contracted to complete the project, using their scanning equipment and technical know-how.
Use of HDS scanners not only performed the tasks much quicker than traditional methods, the crew size required was greatly reduced, and access ladders/scaffolding/ harnesses/etc. normally required were not needed. All of this greatly aided in ALARA (As Low As Reasonably Achievable) goals and allowed the plant to acquire the data with significantly less radiation doses than originally anticipated for the project.
The Exact scanning technicians arrived onsite with the necessary metrology equipment, ancillary technology and scientific expertise to scan the complex, hard to reach and hazardous areas of the nuclear power plant. After capturing the as-is 3D data, technicians were not only able to quickly determine all critical high points of the systems, but do so while requiring dose exposure well below Health Physics expectations.
3D scanning is used in virtually every industry, especially where there is complex organic geometry that is difficult to measure by hand. Laser scanning is even used to measure the amount of corrosion in a system. It can detect surface blemishes and rust which reflect differently than the surrounding scan surface, providing possible clues to areas of weakness in the pipe.
While laser scanners are able to scan stainless steel piping effectively, some piping materials do have an effect on the efficacy of the scanning process, explains Mr Solberg. “Shiny, highly reflective and black surfaces are the nemesis of a laser scanner. These materials can cause a reduction in the number of points returned or captured by the scanner. Materials which are typically difficult to scan are very shiny chrome and semi-transparent plastics. These surfaces can be captured but it may require additional efforts; in those instances dusting or a light powder maybe required to help reduce reflectivity.”
The illustrations were essential in the gas voiding project. The images provided the customer a quick snapshot of information in the effort to identify high points along selected pipe runs and determine the need and proper positioning of gas vents.