100 million degrees for 48 seconds: Researchers report longest heat phase in nuclear fusion

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KSTAR research reactor in South Korea: important step taken

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Anthony Wallace/AFP

Nuclear fusion is seen as a hope in the fight against the climate crisis - as a way to produce energy in a climate-friendly way. But the technology is not yet fully developed. The Korea Institute of Fusion Energy (KFE) has now reported an interim success on the way to a fusion power plant that can generate enough electricity to supply households and industries.

In an experiment at the South Korean research center KSTAR, the researchers kept the temperature of ion plasma at more than 100 million degrees Celsius for 48 seconds. It is said that this has already been achieved in several tests that ran between December and February.

Reaching and maintaining extremely high temperatures is a technical requirement for generating energy using nuclear fusion. In 2021, researchers at KSTAR had already set a record. At that time they maintained the temperature of 100 million degrees Celsius for 30 seconds.

In later fusion reactors, the hydrogen isotopes deuterium and tritium will be used in the form of plasma. In the plasma state, the atomic nuclei and electrons separate and exist as an electrically charged gas. However, in order to bring repulsive nuclei together - i.e. to fuse them - very high temperatures are required. The energy released during nuclear fusion will ultimately drive steam turbines, similar to a nuclear power plant, but in which nuclei are split. The usual generators generate the electricity.

»Ultimate« goal: 300 seconds

In South Korea, researchers are working with a tokamak-type fusion reactor. An extremely strong magnetic field causes the fuel to form a shape similar to a donut. The magnets keep the atomic nuclei in a circular path so that they do not hit the outer walls of their container. According to the announcement, researchers have improved technical components in the system to extend the time in which high temperatures are maintained.

The team achieved a record - but their work is far from over: "The ultimate goal of KSTAR is to achieve 300 seconds of plasma operation with ion temperatures of over 100 million degrees," says the statement. To achieve this, the technology would have to be adapted again.

Just recently, a European research group also reported a record - but it involved a different measurement: researchers at the European nuclear fusion facility Joint European Torus (JET) in Great Britain obtained the largest amount of energy ever achieved in a fusion experiment.

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