CPRF/ZTH front-end torus design and fabrication status

Design of the ZTH front-end torus has been completed for a reversed-field-pinch (RFP) machine to be assembled at Los Alamos National Laboratory during FY 92. The Confinement Physics Research Facility (CPRF) houses the ZTH front-end torus. The ZTH torus consists of an Inconel 625 vacuum vessel supported by an external electrically conducting 304L stainless steel shell. Interspace support rings support the vacuum vessel to the shell and also provide accurate radial support for the interspace electrical diagnostics. The shell also supports 48 toroidal-field coils that are mounted to the shell´s external surface. The shell consists of an explosion-bonded stainless steel-copper composite with water-cooling tube assemblies attached to the outer surface. The 0.135-in-thick copper is on the inside surface of the shell and provides an electrically conducting path with the required electrical time constant of 50 ms. The shell plate will be formed to the required toroidal configuration, after which the poloidal and toroidal flanges will be welded to the structure and machined