Module Assembly Process

To realize the cost benefits from modularizing the construction of an AP1000® nuclear power plant, Shaw has developed a unique time- and labor-saving method. This process will be used to assemble the 1,100-ton large structural module that forms an integral part of the auxiliary and containment buildings. It also will be used to assemble the 1,000-ton structural module that forms the steam generator compartments and refueling canal within the containment vessel.

Produced in our Shaw Modular Solutions™ module fabrication and assembly facility, the modules will be delivered by truck to each site in subsections approximately 10 feet wide by 30 to 48 inches thick and 68 to 77 feet long. The subsections are fabricated as flat panels, L-sections and T-sections to fit the configuration of the final module.

The subsections are stored at the sites until they are scheduled to be erected in the assembly building. This building, constructed at each of the project sites, contains the cranes and platens necessary to erect the modules.

The following steps are necessary to complete the module erection:

  • When a subsection is scheduled for installation in the module, a specially designed truck called an up-ender is sent to the storage site where a crane loads the subsection onto the truck.
  • The up-ender backs into the assembly building, where hydraulic cylinders rotate the truck bed 90 degrees, raising the subsection from horizontal to vertical.
  • An overhead crane in the assembly building will remove the subsection from the up-ender and place it on an elevated steel platen.
  • The up-ender returns to the storage site to retrieve the next subsection.

The elevated steel platen makes it possible to achieve the stringent tolerances specified by the module designer. Subsections are aligned and guyed until vertical joints between subsections are welded by automated welding machines.

While the modules are being assembled on the platens, equipment, skids and interior floor sections are delivered by flat-bed truck to the center of the assembly building. Floor sections are welded together and preloaded with equipment and piping skids. As interior compartment sections are completed in the modules, equipment skids and floor sections are hoisted over the top of the module and lowered into position. Floors are sequenced into each compartment working from bottom to top.

When the assembly of the module is complete with all floors and equipment installed, large heavy-lift transporters raise the steel platen and module off the assembly building floor slab, carrying both the module and the platen out the end of the building to the main heavy-lift crane. This crane picks the module off the platen and places it in its final location.