Space reservation for the peripheral components of W7-X

Wendelstein 7-X (W7-X) is a fusion device of the stellarator type with optimized magnetic field geometry and superconducting coils. The scientific goals of W7-X are to confirm the predicted improvement of the plasma confinement and to demonstrate the technical suitability of such a device as a fusion reactor. It is presently under construction at the Max Planck Institute for Plasma Physics (IPP) in Greifswald, Germany. The W7-X machine requires numerous peripheral components such as plasma heating systems, diagnostics, vacuum and cryogenic distributions, water cooling circuits, cable trays and electronics racks. These represent more than 6000 components which will be installed by 2014 in the experiment hall. The extreme complexity of the machine and the (too) small size of the experiment hall require a rigorous management of the space allocated to each component. The space-constrained environment also causes significant challenges in the maintenance scheme of the components. For these reasons, the concept of “Space Reservation” was implemented through CAD models. These take into account the specific maintenance needs and the geometrical tolerances of the components. The aims were: rationalize design processes and minimize iterations in spite of concurrent engineering issues. In this paper, the definition of the component and maintenance spaces will be explained as well as the methodology to manage the conflicts between them. A sampling of different components, their maintenance spaces and their specific needs will be presented to illustrate the challenges posed for the design, the maintenance tools and the assembly procedure.