Design of Assembly Tools for Site Activities of ITER Cryostat

Abstract

The Cryostat is a huge vessel which is manufactured by welding of austenitic steel plates of thickness ranging from 50mm to 250mm thick. It is manufactured in different sectors and segments and sub-assemblies. These sub-assemblies requires fixtures and tools for final building up of the Cryostat. A fixture is used in manufacturing to hold the workpiece securely in the correct position to the machine centre/cutter during operation. In an industry, product quality, quantity and cost of production are largely impacted by fixtures. In this dissertation various tools are designed for the assembly of different sectors and sections to build a Cryostat. The assembly tools comprises of lifting analysis of the sectors and fixture design on which the sectors will be placed/rested to form an intermediate subassembly. The frame should be designed taking care of its compatibility to use for manufacturing of other subassemblies too, in order to optimize the fixture requirement without disturbing the Cryostat assembly schedule. Assembly tools are also subjected to seismic loads and transportation analysis of the subassemblies while manufacturing and installation at site. Static structural analysis has been performed for the Lifting of Base Section, Lower Cylinder, Upper Cylinder, Top Lid, Base Section Central disc and Top Lid Central Cover. The Lifting analysis has been validated against the allowable limits of the Lug materials. Further in this dissertation a conceptual design has been done for the Transportation Frame of Bae Section and Top Lid. The mass of transport frame has been optimized by 35% using topological and topographical techniques. Subsequently, the optmized frame has been simmulated in ANSYS for static structural analysis and validated against the allowable limits of the material.