Fusion Materials and Fusion Engineering R & D in Japan

Materials R & D in Japan is based on the national fusion R & D strategy, where fusion research is clearly defined as the energy oriented and time-driven to meet ITER and DEMO schedule with the early realization of electricity supply from fusion reactor system [1,2]. After more than two decades of the intensive research activities on fusion engineering at Universities and JAERI, these activities have been unified under the management of the ministry of education, culture, sports, science and technology (MEXT) since 2003 with the emphasis on fusion materials and blanket engineering. To meet the definition of fusion reactor materials R & D, two categories of structural materials have been studied, those are; reduced activation martensitic/ferritic steels (RAFs) as reference materials and vanadium alloys and SiC/SiC composite materials as advanced materials. Together with the near term efforts on RAFs as reference materials, long range fundamental studies and development of advanced materials have been extensively pursued especially in the university programs [3,4]. IFMIF is defined as a crucial facility for materials qualification and ITER blanket module tests is also defined as an important milestone for technology integration to satisfy the ITER mission and to meet DEMO schedule. Thus the importance to proceed with IFMIF and ITER in a coordinated way is clearly indicated in the Japanese fusion R & D strategy. Figure 1 is a roadmap for materials and blanket development in Japan. As is indicated in Fig.1, RAFs development and reference blanket development is the first priority under the JAERI responsibility and the advanced blanket system development coordinated with the advanced materials development is very important but the back-up activities under the Japanese university responsibility [5]. Based on the progresses in structural materials R & D, JUPITER-II, the phase-4 of the Japanese universities and the US DOE collaboration on fusion materials research, has been initiated since April 1, 2001. This is the integration activity of blanket and materials engineering, where self cooled liquid blanket and He-gas cooled solid blanket systems are of concern. The JAERI/ORNL collaboration Phase IV (FY1999-2003) was finished and the Phase V program has just started since April 1, 2004 as five year termed program emphasizing the importance to establish clear understandings and basis for blanket design from “neutron radiation effects up to high dpa”.