High speed repetitive injector prototype for magnetic confinement fusion research

The fuelling requirements of future magnetic confinement devices for controlled thermonuclear research (e.g., ITER) indicate a need to upgrade the performance (speed, mas, number of pellets, etc.) of present day pellet injectors. An experiment in collaboration between ENEA Frascati and ORNL has been started, with the objective of demonstrating a repeating pellet injector capable of delivering D2 ice pellets at rates around 1 Hz and with speeds in the range 1-3 km/s, using an existing ORNL extruder and a Frascati two-stage gun. This activity will be carried out in the framework of a collaborative agreement between U.S. D.O.E. and EURATOM-ENEA Association. The result of numerical simulations and preliminary tests of the two devices, which will be matched together in Oak Ridge, are described. The results of a study in course at CNPM-CNR (under ENEA contract) about the possibility of minimizing the piston wear, are also reported.