Pneumatic pellet injector research at ORNL

Advanced pneumatic-injector-based pellet fueling systems are under development at Oak Ridge National Laboratory (ORNL) for fueling magnetically confined plasmas. The general approach is that of producing and accelerating frozen hydrogen isotope pellets at speeds in the range from 1 to 2 km/s and higher. Recently, ORNL provided pneumatic-based pellet fueling systems for the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET), and a new simplified eight-shot injector has been developed for use on the Princeton Beta Experiment (PBX) and the Advanced Toroidal Facility (ATF). These long-pulse devices operate reliably at up to 1.5 km/s with pellet sizes ranging between 1 and 6 mm. In addition to these activities, ORNL is pursuing advanced technologies such as the electrothermal gun and the two-stage light-gas gun to achieve pellet velocities significantly in excess of 2 km/s and is carrying out a tritium proof-of-principle (TPOP) experiment in which the fabrication and acceleration of tritium pellets to 1.4 km/s were recently demonstrated. 27 refs., 10 figs.