V. Rozov

Design Improvements and R&D Achievements for Vacuum Vessel and in-Vessel Components Towards ITER Construction

During the preparation of the procurement specifications of ITER for long lead-time items, several detailed vacuum vessel (VV) design improvements are being pursued, such as elimination of the inboard triangular support, adding a separate interspace between inner and outer shells for independent leak detection of field joints, and revising the VV support system to gain more structural performance margin. Improvements to the blanket design are also under investigation, an inter-modular key instead of two prismatic keys and a co-axial inlet?outlet cooling connection instead of two parallel pipes. One of the most important achievements in the VV R&D has been demonstration of the necessary assembly tolerances. Further development of cutting, welding and non-destructive tests for the VV has been continued, and thermal and hydraulic tests have been performed to simulate the VV cooling conditions. In FW/blanket and divertor, full-scale prototypical mock-ups of the FW panel, the blanket shield block, and the divertor components, have been successfully fabricated. These results make us confident in the validity of our design and give us possibilities of alternate fabrication methods.

Progress on Design and R&D of ITER FW/Blanket

Abstract The electromagnetic (EM) load on the first wall (FW) panel during disruptions is reduced by slots penetrating the copper layer and the SS backing plate. The maximum stress in the central beam is within the allowables under the most significant load induced by halo currents. In the recent ITER R&D, full-scale FW panels have been manufactured successfully by hot isostatic pressing (HIP) as the reference method. The shield block cooling scheme consists of front water headers that distribute the coolant in radial channels. The shield block is composed of four flat forged blocks electron-beam (EB) welded together at the rear side. Recently, full-scale shield blocks were fabricated by drilling/machining and plugging/welding of flat forged blocks, and assembled with a FW panel with a central beam. Detailed design has progressed on the blanket attachments. Buckling tests, fatigue tests and dynamic load tests have been performed on the T-alloy flexible support (550 kN). Mechanical and thermal fatigue tests, and electrical tests in a solenoid coil, have been carried out on the electrical connection (280 kA). Feasibility of the blanket sub-components has been demonstrated through the R&D.

Vacuum vessel port structures for ITER-FEAT

The equatorial and the upper port structures are the most loaded among those of the ITER-FEAT vacuum vessel (VV). For all of these ports, the VV closure plate and the in-port components are integrated into the port plug. The plugs/port structures are affected by plasma events and must withstand high mechanical loads. Based on typical port plugs, this paper presents the conceptual design of the port structures (with emphasis on the supporting system), and the results of analyses performed.

Design and Fabrication Methods of FW/ Blanket and Vessel for ITER-FEAT

Design has progressed on the vacuum vessel and FW/blanket for ITER-FEAT. The basic functions and structures are the same as for the 1998 ITER design. Detailed blanket module designs of the radially cooled shield block with flat separable FW panels have been developed. The ITER blanket R&D program covers different materials and fabrication methods in order make a final selection based on the results. Separate manifolds have been designed and analysed for the blanket cooling. The vessel design with flexible support housings has been improved to minimise the number of continuous poloidal ribs. Most of the R&D performed so far during EDA are still applicable.