Nuclear and thermal analysis of a multi-reflectometer system for DEMO

The reflectometry diagnostics for DEMO is envisaged to provide the radial edge density at several poloidal angles and data for the feedback control for plasma position and shape. The primary integration approach for reflectometry in DEMO involves the incorporation of several groups of antennas and waveguides into a diagnostics slim cassette (DSC), a full poloidal sector to be integrated with the water-cooled lithium lead (WCLL) breeding blanket. As the front-end components of the DSC will be directly exposed to the plasma, an effective cooling system is required. In this work, the temperature distributions of a DSC segment were estimated with a coupled steady-state thermal analysis performed with ANSYS Mechanical and ANSYS CFX, using the system-coupling module of ANSYS Workbench. The results, which also involved the computation of nuclear heat loads with MCNP6, indicate that the proposed cooling system design will lower the operation temperatures by more than 300 degrees C when compared to previous designs. However, there will still be hotspots in some components, with temperatures above the limit of 550 degrees C for EUROFER under neutron irradiation.