Thermo fluid dynamics tests on the single channel prototypes for the spider grids

The ITER Neutral Beam Test Facility (PRIMAPadova Research on ITER Megavolt Accelerator) is planned to be built at Consorzio RFX (Padova, Italy). PRIMA includes two experimental devices: a full-size plasma source with low voltage extraction called SPIDER (Source for Production of Ions of Deuterium Extracted from RF plasma) and a full-size neutral beam injector at full beam power called MÍTICA (Megavolt ITER Injector Concept Advancement). The beam source components are exposed to high and focused heat loads during beam production, and they are actively cooled, being at high voltage, by ultrapure water, which flows through cooling channels machined inside the components. The high power loads, the complexity of the cooling circuits, and their small, rectangular cross sections are design critical issues. The results of the tests carried out on the single cooling channel prototypes (SCPs) for the SPIDER accelerator grids and their performances in terms of pressure drop and heat exchange calculation are presented. The SCPs have been tested in environmental conditions similar to injector ones, i.e., they have been subjected to thermal loads up to the average heat power density of 1 MW/m 2, in a vacuum environment (0.5 Pa). The experimental results have been cross-checked with computational fluid dynamics analyses and analytical models.