UK investing £2.5bn to chase ‘holy grail’ of nuclear fusion

It needs temperatures hotter than the sun, but Britain’s thriving fusion sector is getting public money to wean us off foreign energy

Ministers are making a £2.5 billion attempt to spark a nuclear fusion revolution that will give Britain “complete energy independence” from the price shocks of foreign wars.

On Monday, Lord Vallance, the science minister, will announce details of a five-year investment in fusion, including building one of the world’s first prototype fusion power plants in Nottinghamshire and developing a UK sector projected to employ 10,000 people by 2030. 

Huge strides have been made in the science of nuclear fusion in recent years. Britain is competing with the United States, China, Germany and Japan. 

Despite the potentially transformative impact of fusion, which in theory could provide limitless clean energy and create a £12 trillion global market, no country has managed to use this fledgling technology to generate useable electricity.

Nuclear fusion works by mimicking the reaction that takes place at the centre of the sun. Unlike conventional nuclear power, which splits atoms apart in a “fission” reaction, nuclear fusion works by forcing them together. There is negligible radioactive waste to dispose of as a result, and minimal safety implications.

Before tomorrow’s publication of the government’s fusion strategy, Vallance said the Iran war demonstrated the need for the UK to translate scientific expertise into commercial energy generation. 

“This has the potential to completely change how [we] think about energy provision,” he said. “Fusion is in many ways the holy grail of how you get clean, effective, limitless energy. That’s why it’s such an important thing to get developed into a practical solution.”

Vallance, 65, who first came to public attention as the government’s chief scientific adviser during the Covid-19 pandemic, said energy sovereignty would protect us from the kind of price uncertainty seen in the last fortnight.

He said: “The current crisis shows that energy prices are volatile and they’re internationally determined. The more we can be self-sufficient and in control of where our energy comes from, the more protective we can be, not only of household bills — which is crucial — but also energy bills for companies and our industrial sector. And that’s precisely why we’ve got very strong renewable development in the UK, it’s why we’re backing nuclear, and it’s ultimately why we’re also backing fusion.”

The main type of fusion forces together two atoms of hydrogen, the most abundant element in the universe, to form helium, releasing a surge of energy. The process was first demonstrated more than 70 years ago, but replicating the physics of the centre of the sun is a major engineering challenge. 

In the sun, hydrogen fuses under the immense force of gravity. On Earth, it has to be achieved with extreme heat and pressure, which usually requires more energy to be put in than the reaction generates. This is the problem that engineers are trying to solve.

To do this, the UK is backing a spherical tokamak design. In that approach, two isotopes of hydrogen — called deuterium and tritium — are heated to 150 million degrees Celsius, about ten times hotter than the centre of the sun, until they form a plasma and fuse together, making a helium atom and unleashing a high-energy neutron. 

It takes substantial energy to power the extremely strong electromagnets required to keep the ball of super-hot plasma in place and stop it from melting the walls of the reactor.

Scientists in the US have recently demonstrated that different technical approaches can be used to achieve “energy gain”, and Britain is determined to show that its approach is also a cost-effective way of generating power.

It is investing an initial £1.3 billion into a prototype fusion power plant called Step (Spherical Tokamak for Energy Production) on the site of a decommissioned coal-fired power station at West Burton in Nottinghamshire.

Paul Methven, chief executive of the government-owned UK Industrial Fusion Solutions, which is delivering the Step project, said the aim is to get the reactor operating early in the 2040s. “It’s quite an aggressive programme,” he said. “We need to show that we can achieve genuine ‘wall socket’ energy — which has not been done before.”

On Monday, Vallance will also announce £180 million for a facility in Culham, Oxfordshire, to manufacture tritium fuel and £50 million for training 2,000 scientists and engineers in fusion-related disciplines. 

The government is also buying a £45 million fusion-dedicated AI supercomputer called Sunrise to model plasma physics. Scientists at the UK Atomic Energy Authority last year developed an AI model that can rapidly simulate how the ultra-hot fuel in a fusion power plant will behave, cutting calculations that previously took days down to seconds.

Vallance, who was one of Sir Keir Starmer’s first appointments after the general election in 2024, said the UK has been one of the world leaders of fusion science for decades, but now the country must seize the chance to convert that knowledge into a workable industry. 

“If we don’t back it, we will end up being the place that did all the discovery and never made the product,” he said. “And there’s a long history of that for the past 50 years in the UK, in a number of scientific areas.”

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He will also announce new support and collaboration for the many fusion, robotics, engineering and AI start-ups working in Britain, to develop a strong supply chain for a new fusion sector.

One of those companies, Tokamak Energy, which spun out from the UK Atomic Energy Authority in 2009, has already built a smaller reactor that has informed the Step design. In March 2022, it became the first private organisation in the world to surpass 100 million degrees Celsius in its reactor:

Dan JOSEPH FOR THE SUNDAY TIMES

Another company, First Light Fusion, based north of Oxford, uses a different fusion technique called inertial fusion, in which tiny droplets of fuel are subjected to immense pressure until they fuse. To generate revenue, it has started working with space and defence organisations to share its expertise and the equipment it uses to create high-pressure environments.

Vallance said: “Other people are going to need to buy this across the world. The UK, having invested heavily in this for a long time and having the world’s biggest nuclear fusion laboratory, has the potential to turn this into reality, and that’s what we’re trying to do. And we’re now at a stage when actually there’s evidence to say, you’ve got to go with this and try and turn it into something — or pack up and go home.”