فعالیت های تحقیق و توسعه روکش کاری در ژاپن در رابطه با نیروگاه های همجوشی

Research and development on both the solid breeder blanket and the liquid breeder blanket have been conducted in Japan towards the fusion power reactors. The solid breeder blanket, one of the most realistic systems based on the present technical data base, is under development within Japan Atomic Energy Research Institute in collaboration with the Japanese universities. On the other hand, the liquid breeder blanket has been studied mainly within the universities as a future alternative blanket system considering its merits like a simple structure and a high accommodation to radiation damage. The present paper overviews the long-term development program and the current status of R&D on the breeding blankets towards the DEMO reactor.

Recent progresses on the fusion plasma researches have made it possible to proceed intensively a development plan for a breeding blanket system aiming at the electric power generation in the fusion reactors. As a most realistic blanket system to produce high heat for the power generation, a solid breeder blanket cooled by high temperature pressurized water has been proposed and applied for the design of DEMO reactor SSTR [1]. It utilizes layered small pebbles of tritium breeder and neutron multiplier installed in a reduced activation ferritic steel box structure. The electric power generation efficiency is expected to be comparable with that of the fission reactors due to its cooling conditions. In order to realize a higher efficiency, an advanced solid breeder blanket cooled by high temperature pressurized helium gas has been proposed for the design of the power reactor DREAM [2]. In the design, SiC/SiC composite is utilized instead of the ferritic steel as a structural material. Presently, our major efforts are concentrated on the R&D on the water-cooled solid breeder blanket for the DEMO reactor considering the ferritic steel as a most realistic structural material. As an alternative, one also pursues an advanced blanket system based on liquid breeder cooling considering its merits like a simple structure and a high accommodation to radiation damage. Force free helical-like reactor (FFHR) is a design study for DEMO reactor which utilizes Flibe (Li2BeF4) as breeding material and coolant conducted by National Institute for Fusion Science (NIFS) and researchers in Japanese universities. Development of the solid breeder blanket is primarily conducted by Japan Atomic Energy Research Institute in collaboration with the Japanese universities, while the liquid breeder blanket has been studied mainly within the universities and NIFS. The present paper overviews the long-term development program and the current status of R&D on the breeding blankets towards the DEMO reactor.

Research and development on both the solid breeder blanket and the liquid breeder blanket have been conducted in Japan towards the fusion power reactors. R&Ds on the solid breeder blanket, the main option for the design of the DEMO reactor, have made progress in recent years, particularly in the area of manufacturing technologies for the blanket structure made of the reduced activation ferritic steel F-82H and also for the Li2TiO3 breeder pebbles and the Be multiplier pebbles. Engineering database on the solid breeder blanket has been accumulated steadily aiming at the module test in ITER. On the other hand, the liquid breeder blanket has been studied mainly by the universities and NIFS as a future alternative blanket system. Though the researches on the liquid breeder blanket, including researches on ceramic coating, are still in a fundamental level or an experiment-room scale, many useful results have been obtained so far. Additionally, a systematic study on flibe (Li2BeF4) has started in order to clarify the applicability or limit of this material to the fusion blanket from the view points of hydraulics, heat transfer, compatibility and tritium control. Intensive research and development on both the solid breeder blanket and the liquid breeder blanket will be continued within Japanese universities, NIFS and JAERI collaboratively to realize an attractive DEMO blanket system.