Current Issue #488

Gone Fission: Could Nuclear Fusion Solve SA's Energy Woes?

Gone Fission: Could Nuclear Fusion Solve SA's Energy Woes?

Renewable energies are “old hat already” says Dr Jessica L. Paterson, and our energy future is bright thanks to the potentially limitless power supply that fusion reactors could bring us.

You may have recently watched Jay Weatherill throw down with Federal Energy Minister Josh Frydenberg over the Commonwealth’s blame game regarding South Australia’s energy issues, and the role of renewable energy sources in the state-wide blackout of September 2016. You may also know that the federal Labor party is aiming for 50 per cent renewable energy by 2030. This may have left you perplexed about the meaning/value/function of renewable energy sources. I’d like to tell you that this article will answer all your questions, but really I’m here to tell you that renewables are old hat already – or will be. Enter: fusion reactors.

The kind of technology previously described as “about 10 to 20 years away”, fusion reactors are shaping up to be the flux capacitor of modern times. So what actually are they? Unlike the current crop of fission-based nuclear reactors, where huge molecules are split apart to release energy, fusion reactors involve smashing together much smaller molecules to make larger ones, which also releases energy.

Fusion-based nuclear reactors may render older fission plants almost pointless

One example you may be familiar with is our sun. In fact, stars are the O.G. of fusion reactors. The sheer power of the gravity of a star pulls matter closer and closer to its centre, where fusion occurs. This releases vast amounts of energy, and produces all the different elements we so enjoy today. If early estimations are true, fusion reactors could potentially offer unlimited energy for all, with no waste products other than helium (which we’re running out of anyway – party planners rejoice!).

Harnessing the power of the sun doesn’t come easy. Because we can’t have the gravity of the sun in a laboratory setting, we have to go one better and make fusion reactors hotter than the core of the sun. Given that nothing on the planet is going to withstand that kind of abuse, how on [or off] Earth can we build such a thing?

Inside a fusion reactor is plasma: a very hot soup of charged particles, which can be controlled by a magnetic field. In order to confine the plasma, it is twisted into a loop by super powerful, superconducting magnets. These magnets are so exotically weird that they have to be run at almost absolute zero, which is only the coldest anything can get – even in the darkest reaches of space. So we have, at the core of the doughnut-shaped machine, plasma hotter than the core of the sun, buffered by magnets as cold as deep space. It’s a real tournament of minds for engineers, as you might imagine.

There are two competing designs for fusion reactors: the first is called a tokamak (sick band name, by the way), originally invented by the Russians. A tokamak is a simple doughnut shape: symmetrical and straightforward, but not all that easy to get going and keep working. Because of the nature of magnetic fields, the field containing the plasma is stronger at the middle than it is at the periphery. This means that it’s difficult to keep the elusive plasma contained. If it’s not contained, it dissipates, and we are once again plunged into a September 2016-style dark age. Jay can’t handle that kind of stress.

Fusion power could also end the blame game around Australia’s energy sources

The other design, and another ripper band name, is the stellarator. The stellarator has five-fold symmetry, looks like the centre of a pentagram, and literally translates to ‘star generator’. The stellarator was originally the underdog in the race for fusion reactor design supremacy, because of the complicated twists in the design necessary to contain the plasma. In fact, only a super computer has been able to calculate the exact proportions of the magnets needed to create the stellarator. There is one of these housed in Germany’s Max Planck Institute of Plasma Physics. It’s been named the Wendelstein 7-X, which is probably the nerdiest name we have ever heard for something so cool. Maybe they should have asked the Russians.

Though a (magnetic) field still in its infancy, fusion reactors offer the promise of infinite energy that is “too cheap to meter”, with the primary waste product being enough helium-filled balloons to warm even the darkest heart.

Dr Jessica L Paterson, Senior Research Fellow, CQUniversity, Appleton Institute

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