Research of PAUT on butt weld of EBW of SS for CFETR vacuum vessel

China fusion engineering experimental reactor (CFETR) port stub is made by electron beam welding (EBW) and the ultrasonic scan test and X-ray radiography were designed to conducting the stainless steel (SS) weld quality inspection. In order to overcome the disadvantages of traditional ultrasonic testing, Phased array ultrasonic testing (PAUT) technology has been introduced. Electron beam welding’s structure features has been introduced in this paper which based on the block of the theoretical calculation and the validation of practical method to verify the effectiveness of the selected probe and its signal-to-noise ratio satisfies the requirement of related standards. This experiment may provide a theoretical basis for subsequent processing design.