W/Cu PFCs Defects Detection with Infrared Non-destructive Examination Method for EAST

Abstract

Plasma facing components (PFCs) for the fusion device are employed to sustain the heat flux (10–20 MW/m2) and plasma particle flux in steady-state and transient conditions. Therefore, the performance of the PFCs is essential to maintain safe operation of the reactor. Before installation of the PFCs, the defects must be detected. Infrared non-destructive examination method is a novel non-destructive detection, having the advantages of non-contact, large detection area, fast detection, visual examination result. The active infrared non-destructive examination technology has been developed based on the structural feature of the PFCs and the active infrared thermograph facility is established. Experimental study is conducted with W/Cu PFCs samples with different sizes of artificial defects and with no defects, in which the infrared thermograph images are obtained. The detecting ability of the infrared non-destructive examination is evaluated by analyzing the temperature distribution of the samples. Based on the study of infrared thermograph processing methods, surface temperature error of the samples caused by uneven emissivity can be eliminated by maximum temperature deviation reconstruction method. Furthermore, fast discrete Fourier transform method can help increase the signal-to-noise ratio and realize defects distinguishment. As the supplementary of the experiments, numerical simulation is used to investigate the key influences of the active infrared non-destructive examination method with the finite element model for samples with different defect locations, defects sizes, mass flow rate of the coolant and the temperature of the coolant.