AbstractThermal tests using JAERI electron beam irradiation systems (JEBIS) have been carried out on B4C-converted carbon-fibre-reinforced composites (CFCs) and B4C-converted isotropic graphites made by the chemical vapour reaction (CVR) method. The thickness of the B4C layer was 150–1300 μm. Irradiations were performed under two different heating conditions: 5–20 MW m−2 for 5 s and 1100–1600 M m−2 for 2–3 ms. Measurements were made with respect to weight loss and changes in surface morphology.No significant surface damage except for a small weight loss was observed in the B4C layer of all samples made by a single conversion treatment at a heat flux of 10 MW m−2 for 5 s. Exfoliations and surface melting occured in the B4C layers on isotropic graphites made by multiconversion treatments at a heat flux of 10 MW m−2 for 5 s. Therefore, single-treatment B4C-converted CFCs and B4C-converted isotropic graphites can be used as the divertor material for JT-60U application.
Thermal fatigue tests with actively cooled divertor mock-ups for ITER