Inside China’s race to lead the world in nuclear fusion

Tokamaks are doughnut-shaped machines that generate the same nuclear reactions that power the stars.

They use magnetic fields to confine heated loops of plasma at temperatures hotter than Sun ’s core.

The aim is to force atomic nuclei to fuse, releasing energy.

This could be harnessed as a source of almost limitless clean power, if the scorching, unstable plasma can be maintained and controlled.

Many researchers say the most practical approach to fusion energy will entail using a tokamak to confine a long-lived burning plasma’ If scientists can do this, fusion could offer a safer, cleaner alternative to conventional nuclear-fission power plants that split heavy uranium nuclei, producing radioactive waste that can remain dangerous for thousands of years .

By the 2040s , its goal is to deliver more than ten times as much heat as is directly put into the plasma, the milestone for viable fusion, and also to produce up to a gigawatt of net power.

If this could be achieved, demonstration power plants would then produce grid electricity.

China ’s strength in fusion research lies not so much in engineering innovations, says Allain .