Divertor target with liquid metal jet impinging upon a solid surface

Free surface liquid metal flows (film and jet-droplet flows) have been investigated recently as divertor targets. They are claimed to be capable of accumulating heat fluxes up to 100 MW/m2 under reasonable liquid metal velocities. To avoid their main drawback associated with possible plasma contamination, another concept was proposed where liquid metal jet impinges upon inner surface of solid tile, facing the plasma, and flows as a thin film. The distinction from channel type flow lies in the fact that in this case the target cooling system is not hermetical and replacement of tiles can be easily achieved. The following analysis was made to prove the feasibility of this concept: thermomechanical calculations, MHD tests of mock-ups, and construction materials wettability tests. Thermomechanical analysis was made for carbon-based armor tiles cooled by LM jets from rear side. Two LM coolants (Ga and LiPb) having different initial temperatures (50 degrees C and 280 degrees C correspondingly) were considered at flow velocities from 0.5 to 3.0 m/s. It was shown that allowable surface temperature of the tile (<1200 degrees C) may be kept at reasonable flow velocities and significant (>5 mm) tile thickness