A Small Rectanagular Edge Localized Mode Control Coil Design able to Withstand a 400oC Environment
Authors: M. Viola, F. Dahlgren, P. Heitzenroeder, T. Meighan, P. Titus, P.M. Anderson, and A.G. Kellman
Abstract: Abstract-Recently, an Edge Localized Mode (ELM) control coil
was developed for use on the DIII-D tokamak. The coil design
represented a significant challenge due primarily to the
requirement for the coil insulation to withstand bakeout
temperatures of 400oC for extended periods. This requirement
ruled out most common organic insulating systems and
necessitated a significant prototyping and development effort,
leading to the selection of an advanced high temperature
glass/polyimide resin system. The development included
developing a heating mechanism that provided the discrete
temperature ramp cycles and cure cycles required by this exotic
resin. To complicate matters, the resin had a limited shelf life.
Additionally the coil was small and rectangular in shape with
rather small corner radii. This created a corner buildup that was
not previously encountered and made dimensional control
difficult. Another unique design requirement was the need to
apply a sufficient internal pre-load to the wound and cured coil to
insure there will be no relative motion between the coil and the
Inconel case due to Lorentz forces from the 4 Tesla toroidal field
on the vessel center post. This led to development of very unique
leaf springs and a significant research and development effort
coupled with an equally arduous finite element analysis effort. A
satisfactory prototype was produced. This paper will focus
primarily on the manufacturing challenges and discuss the
prototyping effort.
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Submitted to: 38th International Conference on Plasma Science & 24th Symposium on Fusion Engineering/ICOPS 2011 SOFE, Chicago, IL, June 26-30, 20011
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