Saint-Paul-lès-Durance (France) (AFP)

A weight of 1,000 tons and the size of a seven-story building: the first part of a gigantic magnet, announced as the most powerful in the world, arrived Thursday at the site of the experimental nuclear fusion reactor Iter, in Saint- Paul-lez-Durance (Bouches-du-Rhône).

This magnet called "Central Solenoid" constitutes a major step for Iter, an international program bringing together 35 countries which aims to control the production of energy from the fusion of hydrogen, as in the heart of the Sun.

Manufactured by General Atomics in California, this first 66-ton part arrived at the construction site of the future reactor, by sea from the United States, then by road in an exceptional convoy from the port of Marseille.

The other five magnet modules will complete the puzzle "no later than 2024", according to Bernard Bigot, CEO of Iter Organization.

Once assembled, the "Central Solenoid" will weigh nearly 1,000 tonnes and will measure 18 m high: "it will be the most powerful magnet in the world because it will generate a 13 Tesla field in the heart, that's 300,000 times the earth's magnetic field, "Thierry Schild, technical manager of the solenoid at ITER told AFPTV.

The Central Solenoid will be the "beating heart" of the tokamak Nicolas TUCAT AFP

The superconducting magnet will be placed in the heart of the tokamak fusion reactor, a huge magnetic chamber where the temperature can reach 150 million degrees.

An extreme heat that accelerates the plasma (a hydrogen gas) and allows the hydrogen nuclei to collide to merge into heavier atoms, and release colossal energy.

Magnetic fields, like that of the Central Solenoid, make it possible to confine the plasma in the enclosure, to prevent it from coming into contact with the walls and cooling down.

Iter plans to inject an unprecedented volume of 830 m3 of plasma.

"This is the condition for the plasma current to stabilize, and for us to be able to recover more energy than is injected," explains Mr. Bigot.

The first plasma production should take place in 2026 and Iter should reach full power in 2035.

Nuclear fusion is considered by its supporters as the energy of tomorrow because it could be virtually unlimited and non-polluting.

Iter is nevertheless criticized, especially among environmentalists, who see it as Greenpeace a "scientific mirage" and "a financial pit".

Arrival by exceptional convoy of the first part of the "Central Solenoid" superconducting magnet at the Iter site in Saint-Paul-lez-Durance in Bouches-du-Rhone, September 9, 2021 Nicolas TUCAT AFP

The initial budget has tripled to almost 20 billion euros now.

And "it is likely that it will be revised" due to delays due to the Covid-19 pandemic, according to Bigot.

© 2021 AFP