R&D activities on manufacturing plasma-facing unit for prototype of ITER divertor outer target in JADA

Ezato, Koichiro; Suzuki, Satoshi; Seki, Yohji; Nishi, Hiroshi; Mori, Kensuke; Enoeda, Mikio

Toward the ITER construction, JADA push forward the technology development for outer vertical target for ITER divertor. In this report, resent results on joining technology development between Carbon-based material (CFC) monoblocks and Cu-alloy (CuCrZr) cooling tube and heating test for full-scale divertor prototype are summarized. Joint test reveals cause of defects occurred in the CFC monoblock joint and Improvement on this joint is realized by using Cu-W material as a buffer layer between CFC and CuCrZr instead of conventional soft Cu layer. The joint with Cu-W layer can suppress joint defect in the CFC monoblocks. Furthermore, as a result of repetitive heating test at 20 MW/m in 10 s for 1,000 cycles on the CFC monoblock divertor mock-up with Cu-W buffer layer, the deterioration of heat removal was not observed.