In-operando Evolution of Thermal Diffusivity of W-coated-SiC during Ion Irradiation and Plasma Exposure

We will present the results of the first stage of an experimental campaign aimed at evaluating the use of SiC-based composites as the structural material in advanced vacuum vessel concepts such as the Liquid Sandwich Vacuum Vessel (LSVV). Results will show the evolution in the thermal diffusivity of W thin-film coated cubic-SiC (CVD) during ion irradiation and simultaneous plasma exposure. Irradiations have been carried out at 600 and 800℃ with Si4+ and He2+ ions to understand the effects of irradiation temperature and transmutants on thermal diffusivity. In addition, thermal diffusivity of W-coated-SiC has also been measured during simultaneous plasma exposure and Si4+ ion irradiation. Ion irradiations were performed on the CLASS accelerator and plasma exposure on DINISOS at the MIT. Thermal diffusivity has been measured in-operando using transient grating spectroscopy (TGS). Ex-situ SEM has been used to study the evolution of the surface of W-coated-SiC after plasma exposure. These results are the first in-operando measurement of a key material property during a simulated fusion environment, offering a pathway for rapid down-selection of fusion-relevant ceramic-based structural materials, accelerating the otherwise years-long process to weeks.