Cooling circle design and testing for ITER radial X-ray camera

The ITER radial X-ray camera (RXC), which is installed in the middle diagnostics shield module (DSM) of equatorial port plug 12, is an important piece of diagnostic equipment in the tokamak system. A cooling circle is vital for RXC detectors because it can protect them from being damaged during the DSM baking phase when the temperature reaches 240 (±10)°C. Helium is used as a cooling medium in this cooling circle owing to its low activation and good heat exchange with copper. To increase the gas resistance and expand the heat transfer area, a labyrinth structure is introduced into the internal structural design of a heat exchanger. In this paper, an analysis of the heat load of the RXC and its cooling circle is presented, along with the thermal simulation and test results. Thermal simulation results indicate that the cooling circle design can meet the requirements. A test platform is built to validate the cooling circle design. The experimental results are presented, and the problems encountered during the testing are analyzed. The test results indicate that the maximum temperature of the detector is lower than 65 °C with the cooling circle during the platform baking phase, which is lower than the detector operation temperature limit of 75 °C.