Shooting selected pellets into the plasma
13 Jun 2016
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Lynne Degitz, US ITER
The US ITER pellet injection team has designed and fabricated a new dual nozzle test article that will support both fuelling pellets and ELM pacing pellets in the ITER Tokamak.
ITER will require significant fuelling capability to operate at high density for long durations. Pellet injection provides efficient core and edge fuelling of deuterium or a deuterium/tritium mixture; the system will also deliver deuterium pellets to the plasma edge to mitigate edge localized mode instabilities (ELMs).
The US ITER pellet injection team based at Oak Ridge National Laboratory (ORNL) has designed and fabricated a new dual nozzle test article that will support both fuelling pellets and ELM pacing pellets in the ITER Tokamak.
The article was manufactured by Apollo Corporation in Wartburg, Tennessee. The component features shut-off nozzles which permit the selection of 5 mm fuelling pellets or 3 mm ELM pacing pellets; it is also possible to adjust the pellet length in order to tailor the amount of fuel or ELM pacing material delivered to the plasma.
A test stand at the ORNL Pellet Lab is being prepared and testing of the component will occur later this year. In the ITER machine, the pellets cut from the dual nozzle assembly will travel through the pellet selector to the pellet guide tubes, which direct fuelling and ELM pellets to specific areas of the plasma.