Nondestructive Testing of EAST W/Cu Divertor Components

Recently, the EAST W/Cu divertor components, including the ITER-like monoblock W/Cu units and flat-type W/Cu units, have been developed by Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) in collaboration with Advanced Technology and Materials Co., Ltd. (AT&M). To detect the bonding quality in these multiple layer geometry W/Cu plasma-facing components (PFCs) at each step of their manufacture, special nondestructive testing techniques have been researched and developed. For monoblock W/Cu PFCs, the bonding at both W-Cu and Cu-CuCrZr interfaces was qualified by spiral ultrasonic testing (UT) with a focus probe, which was inserted into the CuCrZr tube with a flexible driving tube. Artificial defects with defined size have been measured by UT and compared with the results of high heat flux testing (HHFT). The HHFT demonstrated that the monoblock W/Cu mock-up qualified by this UT has withstood 1000 cycles of heat load at 10 MW/m². The bonding quality of flat-type W/Cu mock-ups has also been inspected by the usual water-gap UT. The results from HHFT at 5 MW/m² demonstrated that the present UT was unreliable for the quality control of the flat-type W/Cu PFCs.