Design and Analysis of Transportation Frame for The Lower Cylinder of ITER Cryostat

Abstract

The Cryostat is the largest high-vacuum pressure chamber which provides the high vacuum, super-cool environment for the ITER vacuum vessel and superconduct- ing magnets. The Cryostat is a huge vessel which is manufactured by welding of austenitic steel plates of thickness ranging from 50 mm to 250 mm thick. It is manufactured in different sectors and segmentation. These sub-assemblies require fixtures and tools for final assembly of the cryostat at cadarache France site. A fixture is used in manufacturing and assembly to hold the work piece securely and to maintain the elasticity during production and erection operation. In an industry product quality, safety and cost of production are largely impacted by fixtures. In this dissertation work design of the transportation frame for the assembly of different sectors and sections to build a lower cylinder of ITER cryostat has been conducted. The frame consists of support structure, mid support ring and top-plate assembly for the ease of welding and assembly of the lower cylinder cryostat and also to maintain the rigidity of the lower cylinder. The frame has been designed taking care of its compatibility to use for manufacturing and assembly of other subassemblies too. Conceptual modelling of transportation frame has been carried out in CATIA software. Manual calculations for the main frame beam and for the support structure has been concluded. Meshing of the lower cylinder transportation frame has been carried out in Hypermesh software. Modelling of the transportation frame and support structure has been carried out in ANSYS APDL. Boundary conditions and specific define load has been applied and various analysis has been concluded in ANSYS APDL. Stress analysis of stools and location of Stools under the transportation frame has been designed in such a way that it does not become the stress raiser in the frame or lower cylinder and also allow the free movement of the SPMT vehicle.