British scientists have smashed a record for generating nuclear fusion in what has been hailed a "milestone" for harnessing clean and sustainable low-carbon energy.
Fusion energy is based on the same principle by which stars create heat and light but it's development has been hampered by technology that uses more energy than is created
In this process, atoms are combined rather than split as in a nuclear reactor, and special forms of hydrogen are used as fuel.
A team at the Joint European Torus (Jet) plant near Oxford generated 59 megajoules of sustained energy during an experiment in December, more than doubling the 1997 record, the UK Atomic Energy Authority said.
The five second burst of the equivalent of 11 Megawatts of energy was enough to power around 10,000 homes albeit over a sort timespan. And the experiment while consuming more energy to create the fusion reaction than the energy released was the longest sustained fusion event of its kind.
The results "are the clearest demonstration worldwide of the potential for fusion energy to deliver safe and sustainable low-carbon energy," it said.
The doughnut-shaped machine used for the experiments is called a tokamak. Inside, a tiny amount of fuel comprising deuterium and tritium – both are isotopes of hydrogen, with deuterium also called heavy hydrogen – is heated to temperatures 10 times hotter than the centre of the Sun to create plasma.
This is held in place using superconductor electromagnets as it spins around, fuses and releases energy as heat.
Fusion is inherently safe in that it cannot start a runaway process.
Gram for gram, it releases nearly four million times more energy than burning coal, oil or gas and creates almost no waste.
The results announced on Wednesday demonstrate the ability to create fusion for five seconds but longer times will be needed for the process to become viable as a conventional source of power.
"If we can maintain fusion for five seconds, we can do it for five minutes and then five hours as we scale up our operations in future machines," said Tony Donne of the EUROfusion consortium.
A larger and more advanced version of Jet is being built in southern France, called ITER, where the Oxford data will prove vital when it comes online, possibly as soon as 2025.
About 350 scientists from EU countries (plus Switzerland, the UK and Ukraine) and more from around the globe participate in Jet experiments each year.
Meanwhile, Demo fusion power plants to supply electricity to the grid are being developed alongside tokamak research devices such as Jet and ITER.
International co-operation on fusion energy has historically been close because, unlike the nuclear fission used in atomic power plants, the technology cannot be weaponised.
Emeritus Professor of energy conversion at the University of Newcastle
The France-based megaproject involves China, the European Union, India, Japan, Korea, Russia and the US.
ITER chief Bernard Bigot hailed the Jet results as the production of energy on a "nearly industrial scale".
Despite dozens of tokamaks being built since they were invented in Soviet-era Russia in the 1950s, none has yet managed to produce more energy than is put in.
British Science Minister George Freeman also hailed the "milestone results".
"They are evidence that the ground-breaking research and innovation being done here in the UK and via collaboration with our partners across Europe, is making fusion power a reality," Mr Freeman said.
Ian Fells, Emeritus professor of energy conversion at the University of Newcastle, said: “The production of 59 megajoules of heat energy from fusion over a period of five seconds is a landmark in fusion research.
“Now it is up to the engineers to translate this into carbon-free electricity and mitigate the problem of climate change.
“Fusion was initiated with the explosion of the hydrogen bomb in 1952, its potential was realised but it has taken until now to achieve five seconds of fusion, a formidable success.
“Ten to 20 years could see commercialisation.”
