CONCEPTUAL DESIGN OF A 2-MEV NEUTRAL BEAM INJECTION SYSTEM FOR THE STEADY-STATE TOKAMAK REACTOR

A conceptual design of a 2 MeV neutral beam injection system for the S teady State Tokamak Reactor is described. The system nominally deliver s a 2 MeV, 60 MW neutral deuterium beam to the reactor plasma through two tangential ports. On each port is mounted one beamline which has e ight ion source/accelerator modules. The modules are arranged off the beamline axis and the accelerated ion beams are deflected by the ion b eam bending system to be guided to the neutralizer cell. This arrangem ent prevents each module from being exposed to an intense direct irrad iation from the reactor and makes it possible to use many ion source/a ccelerator modules per port. Since the ion beam output per module can be reduced, a Cockcroft-Walton type DC high voltage generator is adopt ed, so that high voltage transmission lines can be eliminated. Additio nally, maintenance of the module is easy and simple, since all modules are arranged on the same floor. In this paper, a design of the ion be am bending system, which is a key issue to realize this advantageous a rrangement, is described in detail, together with the overall descript ion of the 2 MeV neutral beam injection system.