Science Illustrated

Fifty Years Away

- Anthony Fordham afordham@nextmedia.com.au

Have you heard about nuclear fusion? It’s this amazing new way of generating electricit­y that creates no pollutants and leaves no nuclear waste. And it’s just 50 years away! Of course, sustainabl­e useful fusion has been 50 years away for about the last 70 years. And because of this, there are people who think the technology will never amount to anything and will always be a pipe dream.

Yet government­s - historical­ly in Europe and the US and more recently in China - continue to invest billions in building experiment­al fusion reactors. China’s rather cutely-named Experiment­al Advanced Supercondu­cting Tokamak (EAST) has hit various operationa­l milestones this year; the Internatio­nal Thermonucl­ear Experiment­al Reactor in France is on track for a 2020 opening; and the National Spherical Torus Experiment Upgrade (NSTX-U) in Princeton continues to do important experiment­al work in fusion plasma creation and containmen­t.

All these projects are massive, in both dollar terms and the sheer size of the toroidal ”tokamak” magnetic containmen­t systems that hold superheate­d plasma. But others are working on so-called ”compact fusion” devices, including Lockheed Martin’s famous Skunk Works.

Yes, there is a LOT of human e ort being put into fusion right now.

And yet despite this, politician­s and public figures deride fusion, and repeat the familiar mocking mantra: ”It’s always 50 years away.”

What these non-scientists don’t release is that the ”problem” of creating and sustaining a fusion reaction to create surplus energy is many orders of magnitude harder than nuclear fission.

A quick recap: fission - our current nuclear power technology - creates energy by allowing unstable Uranium atoms to decay and release a bunch of waves and particles, among which is energy as heat which turns water to steam and drives a turbine. Fusion on the other hand occurs when hydrogen and then helium atoms are smashed together to create new elements and, in the process, release lots of energy which again we’d use, when making electricit­y anyway, to drive a turbine.

Our current level of understand­ing means it’s fairly easy to create an unstable fusion reaction. Our thermonucl­ear weapons are the most destructiv­e example of that, but we can also fuse atoms in particle accelerato­rs and also in devices that basically shoot a bunch of high-powered lasers.

Nuclear fusion occurs in the heart of the sun, where first hydrogen and then helium are crushed together under the force of the sun’s incredible gravity (to compare: the force that keeps you on the ground on Earth is 1g. At the surface of the sun it’s 28.02g and close to the core - which contains 34% of the sun’s mass - the pressure is a mind-melting 265 billion bar.)

The point of mentioning this is that all the sun’s pressure and gravity contains the superhot plasma and keeps the fusion reaction going. Here on Earth, the lack of pressure and intense gravity is good for, you know, living, but not so good for sustaining a fusion reaction.

So these massive fusion projects must solve the problem of how to contain a superhot plasma inside (in the absence of gravity) an intense magnetic field. That’s not an easy problem to solve, but it is one we’re working on, and it’s a problem with a potentiall­y huge payo .

Yeah. It’s going to take longer than 50 years. But be fair: if back in the 1990s scientists told the truth, that fusion wouldn’t be an everyday power source until well into the next century, would they have been given ANY funding?

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