Right now, the UK is in the midst of an energy crisis. Bills are rising, energy companies are going bust, and the importance of switching to sustainable energy is growing in the wake of climate change. There is hope, though – the world’s best and brightest are searching for a solution.
One possible solution is nuclear fusion. No, not nuclear fission – that’s already been a part of the world’s energy landscape since 1954 – but fusion. What’s the difference, though? And why is nuclear fusion a viable option in the shift away from fossil fuels? We’re answering all that and more here.
What's on this page?
What is nuclear fusion?
Nuclear fusion is the process of combining two light atomic nuclei to form a single heavier nuclei. Atomic nuclei are found within atoms, which are the building blocks of the entire universe.
When these atomic nuclei are fused, a massive amount of energy is released – and it is this released energy that we hope to one day use to power the world.
This is the same process that happens within our sun – the intense heat and pressure inside its plasma core create the perfect environment for fusion to occur. Essentially, we are attempting to replicate the mind-bogglingly powerful process that has fueled our sun for the past 4.6 billion years!
We can do this by heating up plasma of our own, to create a sort of ‘mini sun’ here on earth. Such is the power of nuclear fusion that if we were to achieve it, we could theoretically power the entire planet with near-unlimited energy.
How is nuclear fusion different from nuclear fission?
While nuclear fusion is the process of fusing light atomic nuclei, fission is all about splitting heavier ones. When the heavy atomic nuclei are split into lighter ones, an immense amount of energy is released, and it is this energy that is used to power nuclear reactors and fuel nuclear weapons.
The most commonly used element in nuclear fission is uranium, because its atoms are amongst the easiest to split. A byproduct of splitting uranium is of course radiation, something that is normally contained and dealt with. Still, as we’ve seen in incidents like Chernobyl, excess radiation can escape with devastating effect.
Why isn’t fusion widespread yet?
We know how fusion works and we know how to achieve it. The problem is that recreating the intense conditions within the core of the sun, here on earth, is a little difficult to say the least.
First, ‘ignition’ must be achieved. This is close to what it sounds like, in the sense that a ‘spark’ must begin the fusion process, sort of like how a spark can start a fire. The analogy of a fire started with a spark makes an awful lot of sense in the context of successful nuclear fusion.
A lit fire puts out more energy than the spark required to ignite it, and the same is true in nuclear fusion. In order for successful fusion to be achieved, the reaction must put out more energy than it took to start it.
This is currently the biggest hurdle we face, as we don’t yet have the technology to create a self-sustaining nuclear fusion reaction.
How close are we to achieving successful fusion?
Because of the difficulties involved, and the ever-changing landscape of fusion experiments, it’s difficult to say exactly how close we are. Some scientists predict that commercial fusion reactors won’t materialise for another 50-60 years or so. Others think we could have a functioning fusion reactor by as early as 2035. And yet others still believe fusion is a pipe dream that won’t ever be realised (the old joke goes that fusion ‘will always be 30 years away').
We’ve come close in recent years though. In fact, the most recent attempt in August 2021 was the closest we’ve ever come to successful fusion. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory in the US saw its nuclear fusion attempt output six times as much energy as any other previous attempt.
The reaction outputted over one megajoule, which is high enough to be seen as a major step towards ignition. Whilst this is exciting, it’s important to stress that the experiment still needed more energy than it put out.
Another ongoing experiment is happening in the UK, where researchers are attempting to generate more heat than the centre of the sun.
What countries are working on nuclear fusion?
Right now, there are around 50 countries working on nuclear fusion. This includes many countries you’d expect, such as China, the USA, Russia, the UK, and Japan. Other countries, like Thailand and Canada, are also conducting research into nuclear fusion.
One of the most important fusion initiatives right now is ITER (Latin for “the way” or, “journey”). ITER is an ambitious energy project made up of 35 nations all working together to build the world’s largest tokamak. A tokamak is a magnetic fusion device designed to prove that fusion is not only possible, but is a feasible large-scale, carbon-free source of energy.
ITER’s aim is to produce 500 megawatts of energy from only 50 megawatts, thereby demonstrating a successful fusion reaction. What ITER won’t do is actually produce usable electricity – that’s for future fusion projects that’ll no doubt materialise if ITER can prove its viability.
Does nuclear fusion produce radioactive waste?
By far the biggest downside to nuclear fission is the vast amount of radioactive waste that is produced in the reaction. Incidents like the dropping of atom bombs on Hiroshima and Nagasaki in the closing days of the Second World War, and of course the Chernobyl incident of 1986, have made the horrors of radiation linger in all of our minds.
On the other hand, nuclear fusion does not produce long-lived nuclear waste. Instead, a fusion reactor produces helium, the inert gas that makes up 25% of all atoms in the universe. A radioactive element called tritium is also produced and consumed within a fusion reactor, but its half life is so short (just over 12 years, compared to 700 million years for reactor-grade uranium) that it poses little long-term risk.
The beta particles produced by tritium are very low energy too, meaning they aren’t able to pierce human skin. Tritium is also used in loads of everyday objects, including the glowing clock hands in some watches!
Is nuclear fusion expensive?
The astonishing architecture needed for fusion reactors is, to put it lightly, rather pricey. The ITER project itself is estimated to cost a total of $65 billion, and this is just to prove that fusion reactors are a viable option for generating energy.
Once you stack fusion up against the money still being invested in fossil fuels though, it suddenly seems a lot cheaper. According to the IMF, the burning of coal, oil, and gas was subsidised by $5.9tn in 2020.
Fusion’s main problem is that it’s taken an awfully long time to start producing results, having languished in the realm of theory for decades. This has resulted in limited funds from governments, with politicians unwilling (or unable) to commit to investing in something that might not even be possible in their lifetimes – let alone their political terms (unless we’re talking about a dictator perpetuo).
Could nuclear fusion destroy the earth?
Nuclear fusion, whilst capable of outputting tremendous amounts of energy (far more than nuclear fission), cannot destroy the earth.
Say, for example, that a nuclear fusion reaction did get out of hand and somehow destroyed the facility containing it. This would also destroy the hardware maintaining the extreme conditions needed for fusion to occur. Therefore, an out-of-control nuclear fusion reaction would very rapidly begin to contain itself – it's simply not possible for fusion to occur outside of highly specific environments.
Interestingly enough, this was once a concern in the early days of nuclear power – scientists genuinely wondered whether a nuclear explosion would ignite the planet’s atmosphere. Thankfully, even the largest nuclear bombs are not capable of that level of destruction.
Fusion might well be the answer to our pressing need for clean energy, but the question remains – is it too little too late? We need an urgent shift away from fossil fuels, and the reality is that fusion is still some way off. At least in terms of widespread commercial use, anyway.
For the time being, fusion is a fascinating prospect that could still yet save humanity from our reliance on dirty energy. Until it becomes a reality though, other renewable energy sources such as solar panels are our best shot at generating sustainable electricity.