At the National Institute for Fusion Science domestic and foreign researchers together are advancing the design of the helical-shaped Force Free Helical Reactor (FFHR). Based upon the characteristics of plasma and the laws of nature clarified through research in the Large Helical Device (LHD), we are projecting the fusion reactor core plasma performance and advancing designs. But when newer data is required for new features of the design, we seek to heighten our design research such as through experiments conducted in the LHD. In addition, considering energy sources in a future age in which we have realized fusion energy and the use environment for the energy source, we also are considering FFHR designs from the perspective of what functions will be expected of a fusion power plant. Here we will introduce design research for a future-oriented fusion power plant.
Petroleum, coal, natural gas, and other fossil fuels are converted into electrical energy at fire-powered power plants. Not only is this electrical energy delivered to factories and residences by power cables, as gasoline and as city gas it is directly used as fuel for the driving of automobiles, for the kitchen, and for the bath. Approximately 75% of Japan’s energy consumption at present is monopolized by transportation and industry, and by fuel, and the great percentage of that usage is met by fossil fuels. In the future, as the exhaustion of these fossil fuel resources is predicted, meeting this energy need through the use of hydrogen is being considered. At Chubu International Airport, fuel-cell buses that use hydrogen as fuel are at the approval stage for being driven on public streets. And in the hydrogen town in the Yahata area of Kitakyushu, city pipes for hydrogen gas have been laid in public and are delivering 100 kilowatts for use in fuel cells.
Through the FFHR we are considering future needs. Further, in order to secure the flexible operation of power plants, as future-oriented design research, we are considering an FFHR that simultaneously produces electricity and hydrogen fuel. At mid-day when electricity consumption is at its highest, we would supply all of the generated electricity through power cables, and in the evening when consumption is less, we would electrolyze water or steam using surplus electricity, and produce and accumulate hydrogen fuel.
In the fusion power plant which produces electrical power and hydrogen fuel simultaneously, we employ waste heat from the steam turbine used for the generation of electricity in order to extract efficiently mineral resources (lithium, nickel, titanium, and others) from sea water. Lithium currently is found in saline lakes in Central America and South America, and chloride is removed from brine that evaporated salt water. Utilizing scientific methods, a manufacturing plant condenses the lithium. Instead of condensing the salt water by solar radiation, we are considering using the waste heat and undertaking the condensation and evaporation of the salt water. Lithium is invaluable as a material for coolant in the fusion reactor. If we can produce lithium in addition to producing electricity and hydrogen fuel, and, moreover, separate out the deuterium found in hydrogen fuel, then it may be possible to be self-supportive in using this material for nuclear fusion. Making the best use of these good points, we will continue to plan the fusion power plant with an eye toward a clean future in which carbon dioxide is not emitted.