JET-P(93)40

Pellet Injector Technology at JET

The pneumatic repetitive ORNL (Oak Ridge National Laboratory) pellet launcher, which combined with the JET torus vacuum interface using the PIB (pellet injector box) formed the JET pellet injector since 1987, has been returned to the US in the first half of 1992. The majority of pellet experiments at JET so far have been carried out with this combination and a brief description and additional references can be found in [1]. Since 1985 JET has driven the development of high-speed launchers for preferentially deep deposition of fuel and has attempted to employ on the JET machine a practical trial single-pellet launcher (dubbed the PROTOTYPE and described in the following), simultaneously advancing a repetitive universal high-speed launcher (dubbed the Advanced Pellet Launcher or APL) for use up to and inclusive of the Active Phase of JET. This latter device has been cancelled in early stage of its detailed design because of a combination of budgetary problems and vanishing interest in the deep fuelling issue; more information on its design can be found in [4]. Despite of stringent economy measures JET still plans to install for the next operational campaign in 1994 the pneumatic high-speed pellet launcher (now with reduced options) as well as high flow rate pellet centrifuge, an addition to complement the divertor pump now being installed at JET. For both of these pellet launchers of JET design the paper will give a short account of their features and status of preparation. The torus hall scenario of the two pellet injectors on the JET machine can be seen in the schematic of Fig.1.
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JETP93040 796.48 Kb