In the Indian Test Facility (INTF), a Vacuum Vessel is designed to house neutral beam components to provide transmission for length of ∼20 meters which enables characterization of neutral beam parameters.
INTF Vacuum vessel is designed in cylindrical shape and has a detachable top-lid for mounting as well as removal of internal components during installation and maintenance phases of test facility. Principal challenges involved in this are designing the detachable top lid and positioning the appropriate stiffeners within the space available on the vessel for meeting functional and operational requirements of in-vacuum deflection to less than 5mm (0.196 in.) and it is limited to 1mm (0.039 in.) in certain areas on the vessel. Moreover, ASME code  does not have design formulation for this detachable top lid configuration directly, hence, there is a need to adopt the available recommendations ASME code , assess their applicability, adopt appropriate one, improvise and affect it and validate it by Finite Element Analysis (FEA).
This paper presents the comprehensive design methodology adopted for INTF Vacuum Vessel design and optimization of various parameters to meet the operational and functional requirements within the constraints of other mandatory interfaces. This paper also presents its manufacturing plan, fabrication challenges and current status of vessel fabrication.