[en] A structural evaluation of the TFTR Device Vacuum Vessel components was undertaken in order to verify the vessel adequacy in the prescribed operating environment. The products of this investigation appearing in this report include; (1) An evaluation of the required vessel wall thickness for the vessel design operating environment of one atmosphere external pressure and 93⁰C (200⁰F) uniform temperature. (2) A verification of vessel integrity to preclude a fatigue type failure for reactor startup and shutdown cyclic life in the design environment. (3) A verification of stiffening ring structural integrity. (4) A discussion of the design guidelines to be used in providing adequate penetration reinforcement when the desired penetration spacing has been defined