Infrared emissivity of reduced-activation Eurofer 97 for fusion reactor applications

Abstract The spectral directional emissivity of Eurofer 97 is reported between 423 and 873 K for two surface states. Total hemispherical data has been calculated by numerical integration of the measured data and compared to the theoretical predictions based on electrical resistivity data. A semi-quantitative agreement between measured emissivity data and predicted values for Eurofer 97 and similar steels (Grade 91, F82H) has been found, despite larger differences in their resistivities. The reported values for the polished surface are shown to be comparable to data for Grade 91 steel and lower than the usually assumed ones in thermal budget modelling of the DEMO tokamak and other nuclear applications of this alloy.