• Researchers at the Joint European Torus (JET) near Oxford managed to produce 59 megajoules of sustained fusion energy over a five-second period, which was the duration of the experiment. Expressed as a unit of power, that comes to just over 11 megawatts averaged over five seconds.

• The previous energy record from a fusion experiment, achieved by JET in 1997, was 22 megajoules of heat energy. 

• Fusion is one of the most promising options for generating the cleaner energy the world badly needs. Fusion is inherently safe in that it cannot start a run-away process.

• Researchers from the EUROfusion consortium – 4,800 experts, students and staff from across Europe, co-funded by the European Commission – more than doubled previous records at the UK Atomic Energy Authority (UKAEA) site in Oxford using the same fuel mixture to be used by commercial fusion energy power plants.

• The results announced are the clearest demonstration worldwide of the potential for fusion energy to deliver safe and sustainable low-carbon energy.

• The record and scientific data from these crucial experiments are a major boost for the International Thermonuclear Experimental Reactor (ITER), the larger and more advanced version of JET. ITER is a fusion research mega-project supported by seven members – China, the European Union, India, Japan, South Korea, Russia and the USA – based in the south of France, to further demonstrate the scientific and technological feasibility of fusion energy.

What is fusion?

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

• To produce energy from fusion on Earth, a combination of hydrogen gases – deuterium and tritium – are heated to very high temperatures (over 100 million degrees Celsius). 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. A plasma with millions of these reactions every second can provide a huge amount of energy from very small amounts of fuel.

• One way to control the intensely hot plasma is to use powerful magnets. The most advanced device for this is the ‘tokamak’, a Russian word for a ring-shaped magnetic chamber. The JET is home to the world’s largest and most powerful operational tokamak.

• Operated by Culham Centre for Fusion Energy, the Joint European Torus (JET) is the focal point of the European fusion research programme.

• 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.

Advantages of fusion power:

With increasing concerns over climate change and finite supplies of fossil fuels, we need new, better ways to meet our growing demand for energy. The benefits of fusion power make it an extremely attractive option.

The benefits are:

1) No carbon emissions: The only by-products of fusion reactions are small amounts of helium, an inert gas which can be safely released without harming the environment.

2) Abundant fuels: Deuterium can be extracted from water and tritium will be produced inside the power station from lithium, an element abundant in the earth’s crust and seawater. Even with widespread adoption of fusion power stations, these fuel supplies would last for many thousands of years.

3) Energy efficiency: One kilogram of fusion fuel could provide the same amount of energy as 10 million kilograms of fossil fuel. A 1 Gigawatt fusion power station will need less than one tonne of fuel during a year’s operation.

4) Less radioactive waste than fission: There is no radioactive waste by-product from the fusion reaction. Only reactor components become radioactive. The level of activity depends on the structural materials used. Research is being carried out on suitable materials to minimise decay times as much as possible.

5) Safety: A large-scale nuclear accident is not possible in a fusion reactor. The amounts of fuel used in fusion devices are very small (about the weight of a postage stamp at any one time). Furthermore, as the fusion process is difficult to start and keep going, there is no risk of a runaway reaction which could lead to a meltdown.

6) Reliable power: Fusion power plants will be designed to produce a continuous supply of large amounts of electricity. Once established in the market, costs are predicted to be broadly similar to other energy sources.

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