Fabrication of first wall component of ITER test blanket module by HIPping reduced activation ferritic/martensitic steel

Hirose, Takanori; Enoeda, Mikio; Ogiwara, Hiroyuki*; Tanigawa, Hiroyasu

Reduced activation ferritic martensitic (RAFM) steels are leading candidate structural material for the blanket system of fusion reactors. HIP process is the key technology to fabricate the first wall (FW) with built-in cooling channels for ITER test blanket module. This paper summarizes the current status of our investigation on optimization of HIP condition to obtain the excellent joints and evaluation of FW fabrication process. The pre-HIP treatments, such as pre-heating condition to degas, were optimized to decrease oxidation on the joint surfaces which cause degradation of impact properties. With optimized pre-HIP treatment conditions, toughness of the joint was as well as that of the base metal. As for a component fabrication, a FW full-scale mockup has been developed using a RAFM. The deformation due to HIP process was within allowance level due to bracing. Moreover, fine-grained microstructure was obtained with optimized HIP condition and post HIP heat treatment.