First wall/blanket fabrication technology, 2

Hot Isostatic Pressuring (HIP) is the candidate bonding method for the assembly of the in-vessel components (ie. first wall, tritium breeding blanket, divertor and vacuum vessel) for the Tokamak-type fusion nuclear reactor. Investigated in this paper are the mechanical properties (such as tensile properties, impact energy, and low-cycle fatigue strength) of the joints obtained by diffusion bonding instead of HIP and detectability by the ultrasonic detection testing for them. The results show that a joint with a bonding ratio of more than 99 %, has about the same tensile properties and fatigue strength as base metal, though about a 20 % reduction in impact energy occurs in a joint with about a 99 % bonding ratio. In ultrasonic testing, defects in joints with less than a 94 % bonding ratio can be detected using a normal type probe, but, with a focus type probe, defects can not be detected in joints with a bonding ratio of more than 90 %. (author)