The World's First Fusion Reactor Is (Almost) Ready To Turn On

Nuclear fusion has been ‘right around the corner’ for decades. But now, that long-promised future is quickly approaching.

- Caroline Delbert

With tens of billions of dollars on the line, the International Thermonuclear Experimental Reactor (ITER) is almost ready to turn on, 35 years after world leaders, including Ronald Reagan and Mikhail Gorbachev, proposed an international collaboration. While the experimental tokamak – a plasma reactor where extremely hot, charged plasma creates the conditions necessary for atoms to fuse and release considerable amounts of energy – is one of a handful of very costly ‘miniature suns’ in development around the world, it’s arguably the bellwether for self-sustaining fusion, given the seven countries that share its high cost and are invested in its success.

All this time, engineers have been designing and fabricating the planned one million components needed for the reactor. In May last year, they finally installed the first permanent piece at the reactor’s Provence, France, campus: a steel base for the outer shell of the reactor, which has taken 10 years to forge and weld. This piece is the foundation for the ‘giant thermos’, or cryostat, that holds the reactor and contains its heat. The cryostat will be made from 54 parts combined into four main sections, and it will weigh more than 3 800 tons.