Intense neutron source requirements for fusion reactor materials development

Materials research should precede machine construction by at least ten years because considerable time is required for the materials development. When the next generation machine is under discussion, materials scientists and engineers should consider next-next generation device as DEMO for establishing the materials database in time. In this sense, development of an intense high energy neutron source is an urgent problem. Characteristic features of radiation effects with 14 MeV neutrons will be briefly reviewed. Then, the reasons why we need intense source will be discussed. These discussions will lead to identify requirements for the intense neutron sources. There are both near term and long term materials issues which can be studied with such intense neutron sources depending on their capacity. One should also recognize that development of such an intense source will require considerable time and maximum use of existing intense fission reactor neutrons will be one of the practical options for the moment. In other words, the intense neutron sources under discussion should be superior for the study of fusion radiation effects than the existing fission reactors. Items are listed for the evaluation of the sources and some critical comments will be made on several kinds of sources currently being proposed. (author)