Study on characteristics of dissimilar material joints for ITER first wall

Nishi, Hiroshi; Mori, Kensuke*; Enoeda, Mikio; Tanigawa, Hisashi; Tsuru, Daigo; Akiba, Masato; Ioki, Kimihiro*; Lowry, C.*; Pick, M.*

The first wall of ITER blanket includes Be armor tiles joined to CuCrZr heat sink with stainless steel (SS) cooling tube and plate. Qualification tests of the FW fabrication technology are performed in order to qualify the joining technologies. The Japan Atomic Energy Agency has fabricated the qualification mock-up and carried out the materials tests and the non-destructive examinations. The results of tensile test showed that the Be/CuCrZr joint fractured at the interface because of large stress concentration. For the SS/CuCrZr joint, however, the joint fractured at CuCrZr apart from the interface. There was insignificant stress concentration at the interface edges. Since Charpy impact strength of the SS/CuCrZr joint was inferior to the CuCrZr, finite element analyses were carried out. Those fracture behavior were caused from the plastic deformation properties of both materials.