Korean fusion reactor ran seven times hotter than the sun for 20 seconds

9 Sep 2022

The Korea Superconducting Tokamak Advanced Research device. Image: National Research Council of Science & Technology

The director of the Korean research centre said the 2020 experiment marked an ‘important turning point’ in making commercial nuclear fusion reactors.

A fusion device in South Korea made a breakthrough when it maintained a temperature nearly seven times hotter than the sun for 20 seconds.

The Korea Superconducting Tokamak Advanced Research (KSTAR) reactor managed to maintain an ion temperature of more than 100m degrees Celsius “without plasma edge instabilities or impurity accumulation”. The heat of centre of the sun is estimated to be around 15m degrees Celsius.

The record was hit in 2020, but the associated research paper was published this month in the journal Nature after being peer-reviewed.

The researchers noted that other fusion devices have briefly managed plasma at temperatures of 100m degrees Celsius or higher. However, none of them managed to maintain this for 10 seconds or longer.

Nuclear fusion – like the reactions that power stars such as our sun – brings together atoms of light elements like hydrogen at high temperatures to form helium and release tremendous energy as heat.

Fusion has the potential to release massive amounts of clean energy in a way that’s easier to control than nuclear fission, which involves the splitting of atoms.

Si-Woo Yoon, KSTAR research centre director at the Korea Institute of Fusion Energy, said back in 2020 that the technologies required for long operations of such high temperatures “are the key to the realisation of fusion energy”.

“KSTAR’s success in maintaining the high-temperature plasma for 20 seconds will be an important turning point in the race for securing the technologies for the long high-performance plasma operation, a critical component of a commercial nuclear fusion reactor in the future.”

The final goal of the KSTAR is to succeed in a continuous operation of 300 seconds with an ion temperature higher than 100m degrees Celsius by 2025.

“Further improvement of FIRE (fast-ion-regulated enhancement) modes to realise a longer steady-state operation for several hundred seconds with higher performance is foreseen as one of the promising paths towards a fusion reactor,” the research team said in the study.

In February, UK scientists claimed to hit a new milestone of sustained fusion energy in tests conducted on the Joint European Torus (JET), the largest operational tokamak machine in the world.

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Leigh Mc Gowran is a journalist with Silicon Republic