Status of ITER

Abstract

The present status and expected performance of the ITER design is presented. The `Outline Design` (July 1994) has been improved from the standpoint of manufacturing, assembly, maintenance, safety and reliability by a joint effort of the Joint Central Team and the Home Teams. Constant plasma performance and strict limitation of the expected costs were required. The resulting `Interim Design` has the following characteristics: the Toroidal Field (TF) coils are provided with casings and radial shear plates; the increased bending stiffness allows a simpler mechanical structure; the number of TF coils has been reduced from 24 to 20. The new Central Solenoid assembly, including two torsion cylinders, now has a weight of 1350 Tonnes. The vacuum vessel is made of SS 316 LN. The blanket consists of a backplate onto which 1 m*2 m large First Wall/Shield modules are mounted. The divertor has 60 cassettes (3 per sector) cooled by straight radial pipes. An improved maintenance concept allows a full divertor changeover in less than six months. The auxilliary heating has been upgraded from 50 to 100 MW to enable H-mode access and to increase the current drive capability. While the above improvements somewhat reduce the margins for ignition (sustained), beta, and burn duration, the physics performance of the Interim Design and of the Outline Design are comparable allowing all ITER goals defined by the Special Working Group 1 (SWG 1) to be achieved.