AGI – After two decades of design, production, manufacturing and assembly on three continents, the historic multinational nuclear fusion project ITER celebrated the completion and delivery of its toroidal field coilsthe most complex of the ITER systems, coming from Japan and Europe. Each coil is enormous: it is 17 meters high, 9 meters wide and weighs about 360 tons.
The toroidal field coils will work together, in effect, as a single magnet: the most powerful magnet ever made. They will generate a total magnetic energy of 41 gigajoules. ITER’s magnetic field will be about 250,000 times stronger than that of the Earth. Masahito MoriyamaMinister of Education, Culture, Sports, Science and Technology of Japan, and Gilberto Pichetto FratinItalian Minister of Environment and Energy Security, will attend the handover ceremony together with officials of the other ITER members.
The energy of the stars
Nineteen giant toroidal field coils have been brought to the south of France. They will be key components of ITER, the mega-experimental fusion project that will use magnetic confinement to achieve nuclear fusion, the same process that powers the Sun and the stars and provides light and heat to the Earth. Fusion research aims to develop a safe, nearly inexhaustible, and environmentally friendly energy source.
ITER is a collaboration of over 30 countries partners. The European Union, China, India, Japan, Korea, Russia and the United States are involved. D-shaped toroidal field coils will be placed around ITER’s vacuum vessel, a doughnut-shaped chamber called a tokamak. Here, light atomic nuclei will be fused together to form heavier ones, releasing enormous energy from the fusion reaction.
A plasma ten times hotter than the Sun
The fuel for this fusion reaction is two forms of hydrogen.deuterium and tritium (DT). This fuel will be injected as a gas into the tokamak. By passing an electric current through the gas, it becomes an ionized plasma – the fourth state of matter, a cloud of nuclei and electrons. The plasma will be heated to 150 million degrees10 times hotter than the core of the Sun. At this temperature, the speed of light atomic nuclei is high enough to allow them to collide and fuse.
To shape, confine, and control this extremely hot plasma, the ITER tokamak must generate an invisible magnetic cage, precisely conformed to the shape of the metal vacuum vessel. This is where the coils come in. ITER uses niobium-tin and niobium-titanium as the material for its giant coils. Ten coils were produced in Europe, under the auspices of the European ITER National Agency, Fusion for Energy (F4E). Eight coils plus one spare were produced in Japan, under the leadership of ITER Japan, part of the National Institutes for Quantum Science and Technology (QST).
