Manufacturing and high heat-flux testing of brazed actively cooled mock-ups with Ti-doped graphite and CFC as plasma-facing materials

Abstract

In the frame of the EU project ExtreMat new Ti-doped isotropic graphites and carbon fibre-reinforced carbons (CFCs) with high thermal conductivity and reduced chemical erosion were brazed to a CuCrZr heat-sink to produce flat-tile actively cooled mock-ups (MUs). Brazing was done using a low CTE interlayer to shift the stresses to the metal–metal interface. These MUs were exposed to high heat-fluxes in the electron beam facility JUDITH. Screening tests were conducted increasing the heat load stepwise up to 15 MW m−2, followed by 100 cycles at 15 MW m−2, subsequent screening up to 20 MW m−2 and 100 cycles at 20 MW m−2. All MUs withstood screening at 15 MW m−2 and most of them survived screening at 20 MW m−2. Ti-doped CFC MUs showed a significant improvement compared with the undoped reference CFC, surviving several cycles at 20 MW m−2 on all tiles. One of the Ti-doped graphite MUs withstood 100 cycles at 20 MW m−2 on one tile, representing a promising result.