JET find ‘win-win’ scenario for future fusion reactors

03 April 2020

A vital discovery on how to force the extreme heatload away from a fusion reactor’s exhaust system while maintaining high performance has been discovered in recent tests at the Joint European Torus (JET) device at Culham. 

In machines like JET, which use the tokamak reactor concept, an exhaust system known as the ‘divertor’ removes both the extreme heat and impurity particles from the hot plasma fuel.

Scientists working on JET can spread the heat load across different tiles by moving the ‘strike point’, but in ITER the heat load will be much higher than in JET and the strike point cannot be moved. Therefore, not to melt the divertor, the power has to be radiated before reaching divertor tiles.

One solution to this problem is to use a gas as an impurity (often nitrogen) to cool down the plasma by radiating the heat over a wider surface area within the divertor region. The alternative use of neon has meant this hasn’t been able to achieve the same effects as nitrogen without affecting how well the plasma is confined in the tokamak; a key factor in fusion reactor performance.