Fussing Over Fusion

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By Meirin Evans

Fersiwn Cymraeg.

Nuclear fusion is a hot topic when discussing climate change. It could provide alternative energy over the currently popular polluting sources of coal, oil and gas. It would be much more reliable than the niche, clean sources of solar, wind, tidal, geothermal and hydroelectric. However, you can’t mention “nuclear” without reminders of bombs and Chernobyl coming to mind. So what really is it? Could it solve climate change? Is it dangerous? What’s next?

What on Earth is it?

Nuclear fission is what’s used at the moment, which is when heavy elements like Uranium break apart and release energy. Nuclear fusion is different. The masses of protons and neutrons are greater when they are separated than when they’re combined together in elements. For example, the mass of a proton is 1.673 x 10-27 kg and the mass of a neutron is 1.675 x 10-27 kg, adding those gives 3.348 x 10-27 kg. But combined together in an element they have a smaller mass of 3.344 x 10-27 kg. The same goes for lighter elements having more mass when apart than when combined together in heavier elements. Fusion is when light elements, like hydrogen and helium, come together and combine to make heavier elements and release energy. In smashing lighter elements together, you create heavier elements. The extra mass from the protons and neutrons is released as energy following the most famous equation ever. You guessed it, E=mc2. Mass, like kinetic and potential, is a type of energy.

The periodic table. Hydrogen and helium, the lightest elements, are at the top.Credit Flickr Siyavula Education CC by 2.0.

The periodic table. Hydrogen and helium, the lightest elements, are at the top. Credit Flickr, Siyavula Education. CC by 2.0.


Is nuclear fusion our saviour?

Naysayers claim that the world will end because of climate change. So we need an escape, if nothing else, just to change their tone. Fusion is called a renewable energy source because we can confidently say that hydrogen stores on Earth won’t run out before humans. Also, it doesn’t release CO2, a major cause of climate change.

Atomic bomb on Nagasaki in 1945. I certianly wouldn't want to be under that.

Atomic bomb on Nagasaki in 1945. I certainly wouldn’t want to be under that. Credit Charles Levy, National Archives. Public Domain

Is there a catch?

Nuclear has had an “it’s complicated” relationship with the press. Nuclear in the hands of the wrong people can lead to weapons of mass destruction, something best avoided. The media have been quick to cover any story on nuclear leakage, such as Fukushima in 2011. But these events are very rare, especially when put next to happenings like coal mines collapsing.

Why are we waiting?

You might be thinking: let’s get going! Well, slight problem…nobody has gotten fusion quite right. Nuclear fusion is actually safer than the nuclear fission which we use at the moment, since fusion doesn’t make radioactive products. So if we are going to use nuclear as the main energy source in the future, it had better be fusion. Fusion energy definitely will happen, exactly when is unknown. Experts say it’s about 10 years from now, but experts were saying the same thing about 20 years ago… We have managed to get energy out of fusion, but not managed to get a net energy gain. What this means is that the energy put in to start the fusion was more than the energy that came out. What we need at the moment if we want to make the most of the benefits of fusion, is plenty of research and time.


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