Status of Wendelstein 7-X Construction

The Wendelstein 7-X (W7-X) stellarator is the largest fusion experiment presently under construction. The main objective of W7-X is to prove the reactor relevance of a stellarator, based on the HELIAS principle, as an alternative to the tokamak. Details of the optimization criteria and the scientific and technical objectives can be found in several publications. At present, the construction of W7-X is close to the start of the assembly. The first superconducting nonplanar coil is undergoing acceptance testing, the first sector of the plasma vessel has been leak tested, the main parts for the outer vessel have been fabricated, the first ports are close to delivery, and many rigs for the assembly are already installed. The assembly started at the end of 2003 with the attachment of saddle coils for magnetic diagnostics on the plasma vessel and will last until 2009 when the torus will be closed. Start of plasma operation is scheduled for the middle of 2010.