THE SLEEPY VILLAGE THAT’S A VERY HOT SPOT FOR GREEN ENERGY
It’s an unlikely place for a world leader in nuclear fusion, but Culham’s boffins can generate temperatures higher than the sun
IT’S HIGHLY likely the majority of households in Culham were blissfully unaware that late last year, for just a few blistering moments, their sleepy Oxfordshire village became the hottest place in the solar system. Hotter even than the centre of the sun. This stellar event happened just a few hundred metres from their village hall, in the chamber of a space-age machine that looks like something from Doctor Who. But as unlikely as it seems, these incredible thermal explosions are now a regular occurrence.
In the race to create the clean, green energy source of tomorrow, things are really hotting up. And nowhere more so than in Oxfordshire, where researchers are at the vanguard of an energy revolution. The county is home to three machines in which scientists can recreate the same conditions found in the hearts of stars by heating gas up to mind-boggling temperatures of 50,000,000 degrees Celcius and beyond. The machines are called tokamaks and when they are fired up, they become the hottest objects in the solar system. There are several located around the world, but Oxford boasts the biggest, located at Culham Centre for Fusion Energy. Just a few miles away on an industrial estate near Didcot’s Asda warehouse, the same super-thermal reaction occurs in another tokamak that belongs to a private company.
Scientists believe nuclear fusion could deliver the planet from the climate crisis, which makes it arguably the most significant technology in the battle against global warming. If it can be commercially developed, it promises to provide limitless, safe, cheap, green energy. And it is estimated that by 2050, fusion power plants could replace all the energy generated through fossil fuels.
Nuclear fusion is the process that fuels stars. It occurs when lighter atoms collide and fuse together to create plasma, releasing vast amounts of energy. It is the opposite of nuclear fission, which is generated when heavy atoms split into lighter ones.
Commercial fusion reactors run on tiny amounts of hydrogen, can be switched off in an instant and are much safer than current fission reactors.
The only problem is that currently they are only theoretical, like the “Mr Fusion” gadget that Doc Brown attached to a DeLorean car to enable Marty McFly to travel through time in the classic Back To The Future movies. At the moment, fusion can only be achieved on a relatively small scale in experimental tokamaks.
But within the next decade, experts are convinced that science fiction is set to become reality. Governments around the world are investing billions of pounds in the nascent technology, in part through a $20billion global project called the International Thermonuclear Experimental Reactor (ITER). This will be the world’s most expensive science experiment, the world’s biggest tokamak and the world’s first commercialscale fusion machine. Based in Provence, France, it’s scheduled for completion in 2025.
From a 50-megawatt input, ITER is projected to produce an output of around 500 megawatts, enough energy to power a city the size of Leeds or Liverpool.And once the fusion reaction starts, at around 150m degrees, it becomes self-sustaining.
The project was set in motion at the Geneva Superpower Summit in November 1985, when the idea of a collaborative international effort to develop fusion energy for peaceful purposes was proposed by Mikhail Gorbachev to then US President Ronald Reagan.
Today, ITER involves scientists from Britain, America, Russia, China, the EU, India, Japan and South Korea, collaborating to demonstrate proof of concept for commercial fusion power plants. Their work will provide a blueprint around the world.
In December last year, for example, a South Korean tokamak set a new temperature record by reaching more than 100 million degrees Celsius for 20 seconds.
BUT none of these advances would be possible without the groundwork carried out in Oxfordshire at the Culham centre, which is run by the UK Atomic Energy Authority and currently houses the world’s most powerful fusion experiment, a tokamak called the Joint
European Torus (JET). This 10-metre-diameter doughnut-shaped device was designed to study fusion in conditions approaching those needed for a power plant. It was built in the late 1970s and is operated by a consortium of European partners.
In 1997 it set a world record for fusion power generation at 16.1 megawatts. It took 25 megawatts of energy to achieve however, which has been one of the challenges fusion scientists face: how to get out more than you put in. Boris Johnson visited the Culham centre within two weeks of becoming Prime Minister in 2019, saying it was fantastic to “meet the men and women who are helping to invent a sustainable fusion reactor”, adding: “The UK is leading the world in this sector.”
In 2000, scientists and engineers at Culham built a second, smaller spherical tokamak, called MAST. This was upgraded and tested in October last year and is designed to solve another challenge in fusion research: how to handle the exhaust heat created inside a tokamak, which can be 10,000 times hotter than the sun. Professor Ian Chapman, chief executive of the UK Atomic Energy Authority, says scientists are tantalisingly close to solving these puzzles and creating sustainable green energy from fusion.
“It is a really exciting time to be involved in nuclear fusion. The promise is massive,” says Prof Chapman. “Fusion runs on an effectively inexhaustible source of fuel. “There are no safety problems because you can’t have a chain reaction like in a conventional nuclear power plant. You get enormous amounts of energy produced for a small amount of fuel.
“There are no carbon emissions, it is completely renewable. There is an enormous amount to like. There are still technological challenges to overcome – but we are taking big steps.”
The continuation of the trans-European JET project is possible despite Brexit thanks to a clause in the trade agreement that ensures the continuation of British involvement in Euratom, the organisation which oversees fusion research.
And this year activity at Culham will be ramped up when the facility tests the two types of hydrogen needed to sustain fusion, deuterium and tritium. “The data we collect from these experiments will form the basis of what happens in ITER in the middle of the 2020s,” explains Prof Chapman.
Critics say that progress towards a clean fusion future has been too slow. Britain first began testing fusion theory in the late 1950s.
But today there is critical momentum towards the common global goal of unlimited clean energy. Around Oxford, several privately funded spin-offs are promising to help accelerate research and development further, in much the same way commercial companies like SpaceX in the US have boosted the development of space travel.
Tokamak Energy is one such start-up. It operates from a business estate in Didcot, employs 135 people and has its own £50million tokamak, the ST40, which can create plasma at 50 million degrees. Dr David Kingham, executive vice-chairman, told the Daily Express: “Private-sector engagement in fusion is driving development. The UK is still a world leader but progress has been steady rather than spectacular.
“We have reached the point where the scientific understanding is excellent. The investment in ITER is a great vote of confidence but it’s too slow and expensive to be deployed in the time we need.
“We think it’s essential to have something commercially deployable in the 2030s. That way it can have a proper effect on carbon emissions before 2050. Our company objective is to demonstrate commercially viable power to the grid by 2030. It’s a big bold goal but it’s not impossible.”
SCIENTISTS and engineers at Tokamak Energy are concentrating their efforts on the development of compact spherical tokamaks and high temperature superconducting magnets to design a commercially attractive and viable reactor. The technology can then be licensed to companies building power plants. In 10 years, the company has raised £117million of private investment, combined with £13million in government grants.
“So far we have achieved plasma temperatures hotter than the sun,” says Dr Kingham. “It can be done perfectly safely and we take our health and safety protocols extremely seriously.We now want to push that up to 100m degrees. That’s the temperature you need for commercially viable fusion.” Oxford continues to be the global fusion centre thanks to Culham and its historical links to electro-magnetic research.
Oxford Instruments pioneered the use of superconducting magnets in MRI scanning. However, this could soon change. On December 2, the Government issued an invitation to communities around the country to volunteer a site for a new prototype fusion reactor, which would be the first to put electricity into the grid. The project, called Spherical Tokamak for Energy Production began in 2019 with a £222million five-year investment to develop a design. Construction could begin as soon as 2032, with operations by 2040.
“Lots of communities have replied asking for more details,” says Prof Chapman. “Communities will not just be getting an infrastructure project, which will create thousands of jobs, they will get a lot of international recognition for that region and a cluster of support industries around it.”
The only downside? It’s unlikely cars will ever be able to run on fusion. While reactors can be scaled down, they still need copious ancillary equipment to function.
So Marty McFly’s time-travelling DeLorean will remain a distant dream.
‘There are no safety problems like in a conventional nuclear power plant’