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Construction of ITER reactor begins

Assembly of world’s largest fusion reactor underway

Image credit: ITER

Assembly of the world’s largest experimental fusion reactor has started at the ITER facility in Provence, Southern France.

The ambitious ITER project – involving the EU (with the UK and Switzerland), India, China, Russia, the US, Japan and South Korea – aims to build a tokamak nuclear fusion reactor to support the largest-ever magnetic confinement plasma physics experiment. The EU, which is hosting the project, is contributing half the cost, while other members are contributing equal amounts of the remaining costs.

Nuclear fusion is the binding of light nuclei to form heavier nuclei, with a mass deficit being unleashed as energy in the process. Fusion can only occur under extremely hot and dense conditions (such as those found in the core of stars), presenting challenges such as confining and sustaining the plasma at extreme temperatures. In a tokamak reactor, plasma heated to 150,000,000°C is confined in a torus shape by powerful magnetic fields.

The ITER reactor aims to create a plasma which unleashes power of 500MW and sustain it for up to 20 minutes, while just 50MW of thermal power is injected into the tokamak, hopefully demonstrating the feasibility of nuclear fusion as a source of energy.

Construction of the reactor began in 2013. In recent months, components for the reactor have been arriving in Provence from all ITER member groups in accordance with a strict schedule. This month, manufacturing of the largest element of the reactor – the 3,800-tonne cryostat, which surrounds and cools the reactor – was completed in India.

According to ITER director Dr Bernard Bigot, assembly of the tokamak will be akin to assembling a giant 3D puzzle “with the precision of a Swiss watch”.

The start of reactor assembly was viewed remotely by French President Emmanuel Macron and representatives from other ITER members. Shinzo Abe, Prime Minister of Japan, commented: “I heartily congratulate the ITER project. I believe disruptive innovation will play a key role in addressing global issues including climate change and realising a sustainable carbon-free society.”

It is hoped that construction of the reactor will be completed and the first plasma formed in 2025.

A successor to ITER could be the first fusion reactor to provide clean, commercially-viable, essentially unlimited, zero-carbon electricity. A nuclear fusion plant is expected to cost approximately the same as a nuclear fission plant to build, but with no risk of a meltdown and no long-term complications with waste disposal.

Other projects to experiment with nuclear fusion include UK-based Tokamak Energy; the Jeff Bezos-backed General Fusion, and Google partner Tri Alpha Energy.

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