First wall and divertor engineering research for power plant in JAERI

JAERI has successfully developed plasma-facing components (PFCs) for ITER application, and the R&D activities are now being shifted to the development of the PFCs for a fusion power plant. This paper presents the R&D activity on the PFCs, such as the first wall and divertor, for a fusion power plant. The PFCs of the power plant will be subjected to heavy neutron irradiation and high heat/particle fluxes from the plasma during the continuous operation. In the present design of the PFCs, the candidate structural material is a reduced activation ferritic-martensitic steel, F82H, selected for low activation and high robustness against neutron irradiation, and the candidate armor material is tungsten, selected for the low sputtering yield and low tritium retention. To achieve PFCs using these materials, there are several R&D issues to be solved: (1) development of a cooling structure with high heat removal capability, (2) development of a suitable form of tungsten, (3) selection of a bonding technique for F82H and tungsten and (4) evaluation of structural integrity. Recent JAERI R&D achievements and status of these issues are presented.