Assembly begins on ITER, the world's largest nuclear fusion reactor

Lured by the prospect of nearly inexhaustible source of clean energy, scientists have been investigating nuclear fusion reactors for decades, but a new facility taking shape in southern France will provide them with their biggest proving ground yet. ITER is set to become the world’s largest fusion device when completed in 2025, and has just moved into a vital phase with the assembly of the millions components now underway.

ITER, or the International Thermonuclear Experimental Reactor, has been in the works since 1985 and is one of the most ambitious energy projects humankind has ever undertaken. It is a collaborative endeavor involving thousands of scientists and engineers from 35 countries, all working to usher in a new era of renewable energy based on super-hot, high-speed reactions taking place inside the Sun.

These reactions see hydrogen nuclei smash into each under the forces of extreme heat and gravity, fusing together to form helium atoms and releasing monumental amounts of energy. Reactors like ITER are known as tokamaks, and seek to recreate these reactions inside donut-shaped chambers, where massive magnetic coils guide and compress streams of ultra-hot plasma to cause the hydrogen atoms to fuse.

A number of experimental tokamaks are already in operation around the world, but all will be dwarfed by the seven-story ITER. Construction on the building to house the reactor was completed last November after nine years of labor, setting the scene for tokamak experiments that will host streams of plasma 10 times thicker than those in action today.

Rather than actually produce electricity for consumers and industrial applications, ITER is designed to demonstrate that fusion devices can generate energy on that kind of scale. In doing so, it is hoped that it can lay the foundation for future machines that actually capture that energy to produce electricity, while also demonstrating the safety of such a large nuclear fusion device.

There is a ways to go before that happens, however. The machine assembly phase was kicked off at the ITER site in Saint-Paul-lès-Durance today, with French president Emmanuel Macron and leaders from seven ITER member countries attending with the help of video conferencing.

“There are moments when the nations of the world choose to overcome their differences to meet a particular moment in history,” said Macron. “The decision to launch ITER in the mid-2000s was one of those moments. ITER is a promise of peace. When the US, Russia, China, Japan, Europe, India and Korea contribute their best scientists and expertise for the common good, it is proof that what brings together people and nations is stronger than what pulls them apart.”

This assembly phase is expected to take five years, and will require the successful integration of millions of parts built all around the world. This process has been carefully orchestrated, but at its busiest will require around 2,000 workers to piece together the different components. All going to plan, ITER is expected to achieve its first plasma in 2025.

A video of the ceremony can be seen below.

Source: ITER