Why is nuclear fusion taking so long?

We want plentiful, clean, carbon-free electricity, and we want it now. We need it now more than ever; the planet is at its hottest in 115,000 years, and a climate change-denier is about to become president of the world’s second biggest contributor to carbon dioxide emissions. It’s had the potential to became the human race’s saviour for decades, so exactly why are we still waiting for limitless and reliable energy from nuclear fusion?

The nuclear industry currently produces around 11% of the world’s energy, and is considered essential for a low-carbon future. Nuclear fusion has enormous potential, but so far progress has been painfully slow. Now it looks possible that supercomputers could hold the key.

Nuclear fusion is complicated and involves processes that nuclear physicists cannot yet predict. Producing it sounds easy; you put hydrogen plasma into a chamber, force two hydrogen isotopes to fuse, and use the produced heat to drive turbines. Doing that produces much more energy than existing nuclear fission, which splits atoms to create energy. However, while researchers have achieved temperatures of around 100 million degrees, they have done so only by inputting more energy than they can produce.

The problem facing nuclear physicists is plasma physics, the study of charged particles and fluids, and specifically how they interact with electric and magnetic fields. Because the nucleus of atoms are positive, they repel each other unless they’re subjected to huge amounts of energy. The closer the atoms get, the more energy is needed to prevent them from repelling, and eventually fusing.

Work it all out and you can control nuclear fusion. However, in most experiments, scientists have had to use more energy to force fusion than they’ve managed to produce from the fusion itself, achieving the high temperatures needed for fusion for only a fraction of a second.

The most high profile project that’s aiming to make fusion a commercial possibility is the US$20 billion International Thermonuclear Experimental Reactor (ITER) in Saint Paul-lez-Durance, France. A collaboration between 35 countries, ITER is the world’s largest so-called Tokamak, a container that creates a powerful magnetic field lines in a helical shape to hold plasma in place. Its donut-shape is thought to provide the easiest way to predict and therefore, to control the behaviour of the particles as they heat up.

Trouble is, although ITER wants to produce 500 megawatts of energy from 50 megawatts of input, it’s not scheduled to start fusion experiments in 2027. While the ever-delayed ITER dithers, the whole concept of governments and state-funded projects is beginning to look outmoded by a new generation of nuclear physicists taking advantage of recent advances in supercomputers to develop computer models of the processes within plasma physics.

For example, scientists at MIT’s Plasma Science and Fusion Centre recently developed a computer model of the processes inside a nuclear fusion reactor, which took 15 million hours of computer processing time.

In January 2016, scientists at the Institute of Plasma Physics Chinese Academy of Sciences used the China’s Experimental Advanced Superconducting Tokamak (EAST) and created fusion for 102 seconds at a temperature of 50 million Celsius, the longest in a Tokamak fusion device ever. And just before Christmas, physicists at South Korea’s Korean Superconducting Tokamak Advanced Research (KSTAR) reactor kept achieved 300 million degrees for 70 seconds this week. Both used an experimental reactor far smaller than ITER.

Although no-one has yet succeeded consistently at controlling nuclear fusion, the last few years have seen a democratising of knowledge, with scientists at nuclear fusion startups like Canada’s General Fusion, Tri Alpha Energy and Helion Energy in the US, and Applied Fusion Systems, Tokamak Energy and First Light Fusion in the UK all trying to crack the physics using smaller scale experiments.

Results are trickling in, and there’s no guarantees that this new approach will bear fruit. In fact, we’re probably another jump in supercomputer power away from finally solving the riddle of plasma physics. If nuclear physicists can pull it off – and, eventually, they will – it will bring the biggest technological change since the discovery at Oil Creek Pennsylvania in 1859 that kicked-off kerosene production.

Then we can cool-off as Planet Oil becomes Planet Plasma.

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