A conceptual design proposal for a blanket module in the neutral beam injector region of ITER

The development work carried out in Europe on the design of standard blanket shield modules for ITER has been continued, with the objective of further decreasing the fabrication and maintenance costs and demonstrating viable solutions for the most complicated special shield module of the neutral beam injector (NBI) region. A modified attachment system of first wall panels (FWP) to the shield block, using poloidal pins, has been proposed in order to select the same attachment technology for plasma facing components (PFC) of both blanket and divertor systems, to reduce the costs and to simplify the refurbishment of the PFC in the hot cell. The mechanical components of the new attachment system increase the engineering margins against electromagnetic loads and the modified layout of cooling circuits with the proposed fabrication technology decreases the risk of water leakage inside the vacuum vessel during operation. The complicated shape of the special modules of the NBI region, the higher thermal loads in this region and the expected higher probability for FWP exchange requires significant design changes compared to the standard modules developed and reported earlier. This paper describes a design concept developed for the NBI module No. I of the present ITER Blanket segmentation, with a proposed fabrication route. It shows clearly the great advantage of the proposed fabrication technology with respect to design flexibility and reliability compared to standard design and fabrication routes. (c) 2007 Elsevier B.V. All rights reserved.