Design improvements and R&D achievements for vacuum vessel and in-vessel components towards ITER construction

Ioki, Kimihiro*; Barabaschi, P.*; Barabash, V.*; Chiocchio, S.*; Daenner, W.*; Elio, F.*; Enoeda, Mikio; Gervash, A.*; Ibbott, C.*; Jones, L.*; Krylov, V.*; Kuroda, Toshimasa*; Lorenzetto, P.*; Martin, E.*; Mazul, I.*; Merola, M.*; Nakahira, Masataka; Rozov, V.*; Strebkov, Y.*; Suzuki, Satoshi; Tanchuk, V.*; Tivey, R.*; Utin, Y.*; Yamada, Masao*

Although the basic concept of the vacuum vessel (VV) and in-vessel components of the ITER design has stayed the same, there have been several detailed design improvements resulting from efforts to raise reliability, to improve maintainability and to save money. One of the most important achievements in the VV R&D has been demonstration of the necessary fabrication and assembly tolerances. Recently the deformation due to cutting of the port extension was measured and it was shown that the deformation is small and acceptable. Further development of advanced methods of cutting, welding and NDT on a thick plate have been continued in order to refine manufacturing and improve cost and technical performance. With regard to the related FW/blanket and divertor designs, the R&D has resulted in the development of suitable technologies. Prototypes of the FW panel, the blanket shield block and the divertor components have been successfully fabricated.