Down the road, a race to the stars: nuclear fusion

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Creating nuclear fusion, the energy of the stars, takes much more than fireworks…

At a time of ongoing political uncertainty and division, it was good to spend an hour sitting in a crowded lecture theatre in Abingdon hearing about people who are aiming for the stars – or rather, aiming to recreate and harness the energy of the stars. It’s a quest of mythic proportions, with a prize at the end that could change all our lives if only someone can win it: a source of fuel that is clean, safe and abundant. Nuclear fusion is potentially the solution to mankind’s energy needs. And it’s eminently possible that the moment at which it becomes viable will happen just down the road here in Oxfordshire… though as with all quests, there are plenty of obstacles to be overcome first.

Nuclear fusion is the energy of the stars – it’s the process by which the sun generates the light and heat that makes life on earth possible. It’s also how all the heavier elements in the universe were made. There are several projects around the world that are exploring ways of managing and controlling this process, and Oxfordshire is a hotspot for research in this area. When I saw that ATOM, the annual Festival of Science & Technology based in Abingdon, was to include a talk about the subject, I decided to go along and find out more.

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The lecture was held at Our Lady’s school, and it was packed. Alan Costley, who has been working in the nuclear fusion field for 45 years, explained how nuclear fusion works: two atoms are brought together to make a bigger atom – plus energy. However, very specific conditions are required to make this possible, in particular astonishingly high temperatures – ‘fusion temperatures’ of 100 million degrees, hotter than the centre of the sun. Unsurprisingly, this has been challenging to achieve. It was first done around 1965, and successive attempts have got ever closer to the line where the experiments will achieve ‘positive energy’ – where they generate more energy than is put in. At that point, you have a potential fuel source. Apparently, for decades, this positive energy moment was said to be 30 years away. It’s now thought to be five years away.

IMG_2414So who are the players in the nuclear fusion race? There is a huge project backed with multinational state funding, ITER, near Aix-en-Provence in France, where it occupies a 1.5km site. Pictures of the project under development reminded me of the days of early computing – the scale of the machinery, the complex assembly of components. The history of such largescale science projects is, unsurprisingly, marked by delays and overspends. Engineer Rob Manning, who lead the project to land a spacecraft on Mars in the 90s and noughties, was quoted as saying ‘The more money that is invested, the less risk people want to take.’ The result is that projects take longer as caution is built into the designs so as to avoid the danger of costly failure and the waste of public funds. To put it another way, big projects can be slow because they are too big to fail.

What about the nippy new kids on the block? There are several smaller nuclear fusion projects around the world that are supported by private investors, including ARC (Affordable, Robust and Compact) at MIT in the US, and, also in the US, Tri Alpha, and LCP Fusion, which was crowdfunded. There are also two projects in Oxfordshire: First Light Fusion and Tokamak Energy, at Milton Park.

What’s a tokamak? It’s a Russian word (this area of technology, though now the subject of international cooperation, emerged out of the Cold War) and it is a machine in which nuclear fusion takes place – it’s like the engine component of nuclear fusion. OK, here’s the science bit. You thought there were three states of matter, right? Solid, liquid and gas. But at very high temperatures, there is a fourth state: plasma. A tokamak traps plasma in a doughnut-shaped vessel with magnetic coils, and keeps it hot enough for long enough for fusion to occur.

When you’re on a seemingly impossible quest, you need game-changers. At Tokamak Energy, the game-changer is superconductors – materials that have no electrical resistance to currents, so you can keep a current flowing through them for a long time without them overheating. The scientists at Tokamak Energy are also working on making tomamaks that are a slightly different shape. The aim is to create slightly smaller, cheaper machines and to speed up progress towards that positive energy moment when nuclear fusion power becomes a reality.

It is the hallmark of good science communication that everything makes sense at the time – this lecture was definitely an example of that. I hope I’ve done it justice. You can find out more from Tokamak Energy and at @TokamakEnergy. The ATOM Festival of Science & Technology 2017 took place in Abingdon at the end of March, and included lectures on everything from the search to extraterrestrial life to stem cell medicine, self-driving cars and the forthcoming solar eclipse (21 August 2017). Find out more from @ATOMSciFest.

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