Vapotron as Heat Sink for Flat High-Conductivity Unidirectional Carbon-Fiber-Composite Tiles

Two vapotrons from the Joint European Torus (JET) actively cooled divertor design have been fitted by the Japan Atomic Energy Research Institute with unidirectional high-conductivity carbon-fiber-composite tiles and have been tested in the JET Neutral Beam Test Bed. The test section showed excellent uniformity and accepted power densities up to 30 MW/m² for equilibrium pulses. The surface temperature was 1100°C at 20 MW/m². One tile detached at a power density of 25 MW/m². A total of just under 300 pulses at power densities mostly between 20 and 30 MW/m² have been fired onto the test sections without additional failure. The hydraulic parameters were as follows: water inlet temperature, 15 to 20°C; average water pressure in the component, 0.4 and 0.69 MPa; flow velocity, 6.9 and 7.5 m/s.