Nuclear Fusion, where do we stand?
Nuclear fusion seems to more and more as the future of energy, but what is it really? How far are we from this technology?
If you love science — as I do — chances are one of the following articles — or equivalent ones — appeared in your social feeds over the last few weeks:
- Korean artificial sunsets the new world record of 20-sec-long operation at 100 million degrees (phys.org) ;
- China successfully activates nuclear-powered ‘artificial sun’ — National | Globalnews.ca ;
- U.S. physicists rally around an ambitious plan to build fusion power plant | Science | AAAS (sciencemag.org).
These articles promote new advancements in Nuclear Fusion reactors — China’s Artificial Sun’s start-up and the longest fusion reactor run newly set by Korea.
Promoting this technology in such a way tends to make people think that we’re but an inch away from creating a new green, reliable source of energy.
Nuclear Fusion has been a significant part of physics science for the last few years, especially in France — where I reside — with the Iter project [1] (one of the biggest fusion reactors in construction). But how close are we to a working reactor? Is the idea an inch away or, more realistically, a few thousand miles?
I’ve been studying Sciences at the University for the last 3 to 4 years, so I have the chance to be surrounded by physicists. Plus, I actually worked with some Iter engineer, with whom I exchanged a lot about the matter. And for most of them, the answer is clear: we’re still far from a working power plant.
What is nuclear Fusion in the first place?
I want to think that everyone is at least familiar with Fission. But let do a quick recap.
Fission is what we use in all our “nuclear reactors” right now. We take big radioactive atoms — mostly Uranium — send a neutron to break one of them into two pieces, which result in the production of energy and neutrons, which therefore cause onto splitting the other atoms, resulting in a chain reaction. This method to produce energy was discovered in 1938 by physicists Lise Meitner and Otto Robert Frisch and chemists Otto Hahn and Fritz Strassmann. Since then, as all of us know, more and more nuclear power plants poped-up.
About 440 nuclear power reactors generate around 10% of the world’s electricity, right now. We produced around 2657 TWh in 2019, thanks to nuclear. [2]
As of today, Nuclear Fission is recognized by many experts as the only viable source of energy [3]. But we shouldn’t forget that even though we have great mastery, Fission has many problems. Everyone is aware that a small problem can quickly result in an enormous one by manipulating this much energy. Also, Uranium is a non-renewable metal, and waste is challenging to treat.
That’s where Nuclear Fusion comes in handy. Nuclear Fusion is the total opposite of Fission. This time you take two small nuclei and fuse them to create a larger one, some other particles, and energy. The energy is the difference between the sum of the two light nuclei’s mass and the fused atom’s mass. This process has some real benefits. It produced as much energy as the Fission but way less radioactive waste. Plus, the consumable is way easier to get than any other production of power. Deuterium is a promising ingredient because it is an isotope of hydrogen. In turn, hydrogen is a key part of water. A gallon of seawater (3.8 liters) could produce as much energy as 300 gallons (1,136 liters) of petrol [4].
Funny point: Fusion happened in every star, our Sun as well. That’s the phenomenon that produces energy in stars. That’s why some projects — in China and Korea, for example — are called “Artificial Suns.”
The challenges of Fusion — well, mostly plasma
So Fusion is the DREAM. You can produce tons of energy with few materials, without forgetting that the material (seawater) is quite available on our planet. But as with every powerful tech, it, of course, comes with some significant challenges.
The biggest one being that Fusion creates plasma as hot as the Sun — at least — and you have to control this plasma. As stated at the end of the last paragraph, Nuclear is what happens in stars, and everyone knows: stars are hot; for our Sun, around ten million celsius — or eighteen million Fahrenheit. Ouch. You might think that’s hot, but actually, it isn’t; the reactor we are building would go up to ten times this temperature — so about a hundred million celsius. In comparison, the chemical element with the highest melting point is tungsten, at 3,414 °C.
Even with the best material available on earth, we wouldn’t be capable of containing the plasma. But Fusion reactors are being built, and some even started running; how do we do? We do everything we can not to let the plasma touch anything.
Hopefully, plasma is electrically charged so that we can use a magnetic field to manipulate it. The goal is now to control the plasma into staying at a reasonable distance from its surroundings. Multiple containers have been developed for this over the last few years, the most popular one being: the tokamak. It is a circular tunnel surrounded by enormous magnets that create a magnetic field keeping everything in the tunnel’s center.
Now, the real goal arises: what’s the correct magnetic field to apply so that the reactor can run for the most prolonged period. And that is what every team around the world is looking for.
Iter, JT60, the different project in place around the world
As of today, a lot of countries around the world are developing their fusion reactor. For everyone, the goal is creating a reactor that could stay active for days, months, and more, all of this while producing energy.
Here: Nuclear Fusion : WNA — World Nuclear Association (world-nuclear.org); is a list of multiples projects if you want to check their particularities and advancement. World-nuclear is also the perfect website if you ever decide that diving more deeply into the subject is cool.
The difference between research and energy production
Let’s now place ourselves in five to ten years (what most realists research projects are envisaging, at least). Some article will be titled “Iter finally working” or “China’s Artificial Sun ran for half a day”, well maybe. But even if those titles look magnificent, you have to remember: most current — or under construction — reactors are made for research purposes. None of those will actually produce energy, or at least enough power to be called functional.
For a full power plant, most scientists agree that we’ll have to wait for one or two decades. Of course, some interject and claim they have found the solution. My thought on that? Well, maybe, who knows, this is sciences we are talking about. Everything seems impossible until it is not.
If you’re interested, I’d recommend checking the SPARC project (SPARC | Research | MIT Plasma Science and Fusion Center) lead by MIT, which holds quite the promise!
