The design of Steady state Superconducting Tokamak - SST1, is in progress at Institute for Plasma Research, India. The major plasma radius is 1.1 m, minor radius is 0.20 m and elongation is 1.6 to 2.0. SST1 vacuum vessel is a UHV chamber made of sixteen modules insitu welded to form a torus and to maintain modularity with sixteen TF coils. Each module consists of one wedge shaped sector with a radial port and two vertical (top and bottom) ports and one vessel ring. Vessel parameters are, (a) poloidal cross-section is close to D shape, (b) height = 1.6 m, (c) width = 1.0 m, (d) wall thickness = 0.01 m and (e) material of construction SS 304 L. The time constant of vessel (L/R time) is about 7 msec. Vacuum vessel is designed for normal base pressure less than 10(-8) torr and is bakeable to 525K. The vessel will be subjected to, (i) internal as well as external pressure of 850 torr, (ii) electromagnetic loads of 336 KN during plasma VDE, (iii) thermal stresses due to baking at 525K and (iv) loads due to total 110 KN dead weight of vessel and all in-vessel components.

Cryostat is a vacuum chamber which encloses the cold mass at 4.2 K (comprising of magnetic field coils and their supports) and the vacuum vessel and forms a thermal barrier between atmosphere and the cold mass. Cryostat transfers various loads acting on vacuum vessel and cold mass to machine main support structure. It is designed for normal base pressure of less than 10(-5) torr. It is a toroidally continuous polygonal structure of 2.6 m height which inscribes a circle of 4.4 m diameter. The material of construction is SS 304 L and the wall thickness is 0.01 m. The Cryostat will be subjected to, (i) internal as well as external pressure of 850 torr, (ii) electromagnetic loads due to eddy currents mainly during plasma start up phase, (iii) thermal stresses due to vessel baking at 525K and (iv) loads due to dead weight of cryostat and all other components enclosed in it.

The results of design analysis of vacuum vessel and cryostat subjected to various loads carried out using numerical methods and finite element technique (ANSYS) will be presented in this paper.