21adventure

A star is born. And, less than a second later, it dies. On a drab science park just outside the Oxfordshire village of Culham, some of the world’s leading physicists stare at a monitor to review a video of their wondrous, yet fleeting, creation.
“Not too bad. That was quite a clean one,” observes starmaker-in-chief Professor Steve Cowley. Just a few metres away from his control room, a “mini star” not much larger than a family car has just burned, momentarily bright, at temperatures approaching 23 million degrees centigrade inside a 70-tonne steel vessel.
Cowley sips his coffee. “OK, when do we go again?”
Last year, when asked to name the most pressing scientific challenge facing humanity, Professors Stephen Hawking and Brian Cox both gave the same answer: producing electricity from fusion energy. The prize, they said, is enormous: a near-limitless, pollution-free, cheap source of energy that would power human development for many centuries to come. Cox is so passionate about the urgent need for fusion power that he stated that it should be scientists such as Cowley who are revered in our culture – not footballers or pop stars – because they are “literally going to save the world”. It is a “moral duty” to commercialise this technology as fast as possible, he said. Without it, our species will be in “very deep trouble indeed” by the end of this century.
If only it were that simple. Fusion energy – in essence, recreating and harnessing here on earth the process that powers the sun – has been the goal of physicists around the world for more than half a century. And yet it is perpetually described as “30 years away”. No matter how much research is done and money is spent attempting to commercialise this “saviour” technology, it always appears to be stuck at least a generation away.
Cowley hears and feels these frustrations every day. As the director of the Culham Centre for Fusion Energy, he has spent his working life trying to shorten this exasperating delay. Fusion energy is already a scientific challenge arguably more arduous than any other we face, but recent events have only piled on further pressure: international climate-change negotiations have stalled; targets to ramp up renewable energy production seem hopelessly unrealistic; and the Fukushima disaster has cast a large shadow over the future of fusion’s nuclear cousin, fission energy, with both Germany and Italy stating that, owing to safety concerns, they now intend to turn their back on a source of energy which has been providing electricity since the 1950s.
But today Cowley seems upbeat, chipper even. After an 18-month shutdown to retile the interior of the largest of the centre’s two “tokamaks” – ring doughnut-shaped chambers where the fusion reaction takes place – he is bullish about the progress being made by the 1,000 scientists and engineers based at Culham.
“By 2014-15, we will be setting new records here. We hope to reach break-even point in five years. That will be a huge psychological moment.”
Cowley is referring to the moment of parity when the amount of energy they extract from a tokamak equals the amount of energy they put into it. At present, the best-ever “shot” – as the scientists refer to each fusion reaction attempt – came in 1997 when, for just two seconds, the JET (Joint European Torus) tokamak at Culham achieved 16MW of fusion power from an input of 25MW. For fusion to be commercially viable, however, it will need to provide a near-constant tenfold power gain.
So, what are the barriers preventing this great leap forward?
“We could produce net electricity right now, but the costs would be huge,” says Cowley. “The barrier is finding a material than can withstand the neutron bombardment inside the tokamak. We could also just say damn to the cost of the electricity required to demonstrate this. But we don’t want to do something that cannot be shown to be commercially viable. What’s the point?”
At the heart of a star, fusion occurs when hydrogen atoms fuse together under extreme heat and pressure to create a denser helium atom releasing, in the process, colossal amounts of energy. But on Earth, scientists have to try and replicate a star’s intense gravitational pressure with an artificial magnetic field that requires huge amounts of electricity to create – so much that the National Grid must tell Culham when it is OK for them to run a shot. (Namely, not in the middle of Coronation Street or a big football match.)
The fusion reaction occurs when the fuel (two types, or isotopes, of hydrogen known as deuterium and tritium) combines to form a super-hot plasma which produces, alongside the helium, neutrons which have a huge amount of kinetic energy. The goal of plasma physicists such as Cowell is to harness the release of these neutrons and use their abundant energy to drive conventional turbines to generate electricity. The JET tokamak has been shut down for the past 18 months while the interior has been stripped of its 4,500 carbon tiles and replaced with new tiles made from beryllium and tungsten. The hope is that these new tiles will be far more “neutron resilient”, allowing for shots to be conducted for longer periods and at much higher temperatures.
Over lunch at the staff canteen, Francesco Romanelli, the Italian director of the European Fusion Development Agreement, the European agency that funds JET, explains why the new tiles are so crucial: “We now understand how a plasma works. We have demonstrated with JET that we can contain the reactants; we reach temperatures 20 times hotter than the sun’s core and we produce an intense magnetic field, 1,000 times that of Earth’s normal magnetic field. But the main problem we face is plasma turbulence. To compensate for this loss, we have to add more heat and energy. So we are always looking for materials that can withstand these extraordinary conditions inside the tokamak.”
Last year, bulldozers began clearing land 60km north-east of Marseille in southern France. By 2019, it is hoped that the world’s largest and most advanced experimental tokamak will be switched on. The €15bn International Thermonuclear Experimental Reactor (ITER) is being funded by an unprecedented international coalition, including the EU, the US, China, India, South Korea and Russia. Everything learned at Culham will be fed into improving the design and performance of ITER which, it is hoped, will demonstrate the commercial viability of fusion by producing a tenfold power gain of 500MW during shots lasting up to an hour.
But ITER’s projected costs are already rocketing, and politicians across Europe have expressed concern, demanding that budgets be capped. Fusion energy also has its environmental detractors. When the ITER project was announced in 2005, Greenpeace said it “deplored” the project, arguing that the money could be better spent building offshore wind turbines. “Advocates of fusion research predict that the first commercial fusion electricity might be delivered in 50-80 years from now,” said Jan Vande Putte, Greenpeace International’s nuclear campaigner. “But most likely, it will lead to a dead end, as the technical barriers to be overcome are enormous.” Meanwhile, there is criticism from some plasma physicists that the design of ITER is wrong and alternative designs might produce better results for much less money.
Romanelli rejects this analysis. We simply must make this investment, he says: “The prize on offer is too tantalising to ignore. Fusion doesn’t produce greenhouse gases