VACUUM-SYSTEM DESIGN OF THE INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR PELLET FUELING SYSTEM

The International Thermonuclear Experimental Reactor (ITER) will use a n advanced, high-velocity pellet injection system to fuel ignited plas mas. For rampup to ignition, a moderate-velocity (1 - 1.5 km/s) single -stage pneumatic injector and a high-velocity (1.5-5 km/s) two-stage p neumatic injector using pellets encased in sabots are envisioned. For the steady-state burn phase a continuous, single-stage pneumatic injec tor and a centrifugal injector are proposed. The purpose of this study is to simulate the ITER pellet injection line vacuum pumping system t o determine the pump requirements. This study analyzed the injector va cuum system using commercially available vacuum pumps compatible with tritium operation. The vacuum system design program, VSD-II, was used to determine the gas flow through the system components for various pu mping arrangements and component sizes and geometries. The VSD-II comp uter program allows changes to be made easily in the input so that res ults from different configurations are readily obtained and compared. Results are presented and issues in the design are discussed as well a s limitations in the existing pump data.