Fabrication and assembly of full-scale sector models for ITER vacuum vessel

Fabrication of a full-scale sector model of the ITER vacuum vessel, which w as initiated in 1995 as one of the Large Seven ITER R&D Projects, was compl eted in September 1997. The full-scale sector model corresponds to an 18 de grees toroidal sector, is composed of two 9 degrees sectors, Sector A and B , which are spliced at the port center according to the current ITER design . In order to satisfy tight manufacturing tolerances of +/- 5 mm and to ass ure the structural integrity of a double-walled structure, a combination of Gas Tungsten Are (TIG)/Electron Beam (EB) welding and TIG/Gas Metal Arc (M IG) welding were adopted for Sector-A and B, respectively. Although the dif ferent fabrication procedures and welding techniques were employed for the fabrication, both sectors have successfully satisfied the dimensional accur acy of +/- 3 mm for the total height, total width and total wall thickness. After the completion of fabrication, both sectors were shipped to the test site in Japan Atomic Energy Research Institute (JAERI) and assembly test w as begun in October 1997. The first demonstration test of automatic narrow gap TIG welding of the field joints between sectors was successfully comple ted at the end of May 1998. This paper outlines the design and fabrication procedures and describes the results of the fabrication and assembly test o f Sector A and B.