During this experiment, JET averaged a fusion power of around 11 megawatts. JET has produced a record-breaking 59 megajoules of sustained fusion energy over a five second period (the duration of the fusion experiment) using deuterium and tritium – the same fuel mix that will be used in future powerplants. Researchers have overcome many of the scientific hurdles in fusion – developing a good understanding of how to control and confine the hot plasma of fuels. CCFE’s goal is to develop fusion reactors using the tokamak concept. The most advanced device for this is the ‘tokamak’, a Russian word for a ring-shaped magnetic chamber. One way to control the intensely hot plasma is to use powerful magnets. A plasma with millions of these reactions every second can provide a huge amount of energy from very small amounts of fuel.

The gas becomes a plasma and the nuclei combine to form a helium nucleus and a neutron, with a tiny fraction of the mass converted into ‘fusion’ energy.

To produce energy from fusion here on Earth, a combination of hydrogen gases – deuterium and tritium – are heated to very high temperatures (over 100 million degrees Celsius). This is the opposite of nuclear fission – the reaction that is used in nuclear power stations today – in which energy is released when a nucleus splits apart to form smaller nuclei.

When light nuclei fuse to form a heavier nucleus, they release bursts of energy. Fusion is the process that takes place in the heart of stars and provides the power that drives the universe.

Fission and fusion reaction