Development of low activation ferritic/martensitic steel welding technology for the fabrication of KO HCSB TBM

The conceptual design of the Korean helium cooled solid breeder test blanket module has been performed and the fabrication feasibility of the test blanket module concept has been investigated. It is necessary to develop fabrication technology, such as joining technologies of structural material, because low activation ferritic/martensitic steel has been considered for the structural material of the Korean helium cooled solid breeder test blanket module. Several types of the low activation ferritic/martensitic steel have been proposed, but their welding characteristics are still under investigation. In this paper, electron beam welding technologies for the low activation ferritic/martensitic steel were investigated in detail. Tensile, hardness, impact, and microstructure characteristics of the welded specimens before and after post-welded heat treatment have been investigated, and the results show that welding quality and the process applied in this study were found to be reasonable.