Development of double walled vacuum vessel for ITER

Fabrication and testing of the vacuum vessel full scale sector model have been initiated in 1995 as one of the Seven ITER Large R&D Projects to finalize the fabrication process and to demonstrate the required performance of the ITER vacuum vessel before ITER construction. The full scale sector model corresponds to an 18 degrees toroidal sector composed of two sectors, Sector-A and Sector-B, which are spliced and welded at the port centre according to the current ITER design. On the basis of the partial model fabrication, manufacturing procedures and welding methods have been defined so as to satisfy tight manufacturing tolerances of full poloidal sector and structural integrity. A combination of TIG/EB and TIG/MIG weldings has been adopted for Sector-A and Sector-B, respectively. On adopting the segmented configuration of Sector-A and Scetor-B, furthermore, remote cutting, rewelding and weld inspection can be verified for the sector-to-sector connection required for replacement of a toroidal field magnet. The fabrication of the full scale sector model including Sector-A and Sector-B connection will be completed by the end of 1997, and thereafter performance tests on mechanical and hydraulic characteristics are scheduled until the end of ITER EDA. The integration with the midplane port extension fabricated by the Russian Home Team is also planned as a post-EDA activity.