TFTR modifications for D-T shielding

The pending upgrade of the Tokamak Fusion Test Reactor (TFTR) for D-T operation will require extensive changes to the supporting hardware around its perimeter. The entire machine will be surrounded by 30 in of reinforced concrete, making access to the subsystems on the TFTR nearly impossible. A review and modification of each subsystem will be required to ensure compatibility with the concrete igloo. One of the major changes included a complete redesign of the vacuum vessel heating/cooling system. Relocating the main cable tray system which is presently located around the upper perimeter of the machine was another major task. These trays carry the cables for the bakeout heating system and for numerous diagnostic systems. A system to control the routing of existing and new systems that require a penetration through the new igloo or enclosure walls was set up. These penetration documents will control all items passing through the igloo shield. The process by which TFTR will be prepared and modified so that the new igloo walls can be installed is described. Several of the major subsystems being modified are discussed