The use of folding structures in fusion reactors

Three types of folding structures are described, together with concepts for use in fusion machines. The Storable Tubular Extendible Member (STEM) was conceived by the National Research Council of Canada and developed by Spar Aerospace Limited. The Astromast is a folding truss developed by Astro Aerospace Corporation. The X-Beam is an ultrastiff folding truss. X-Beam trusses can extend to considerable distances both horizontally and vertically and can support heavy loads. Two such trusses can be mounted on a remotely controlled vehicle to provide a mobile folding crane able to enter the many confined locations in a fusion machine. It can be used in these locations to eliminate the need for fixed cranes. Because it can be removed before reactor operation and is not exposed to the extreme environment that a fixed crane must withstand, it will have better reliability and maintainability. A brief history of the development of folding structure technology is included