Unlimited, Sustainable Energy… for Millions of Years?!
Imagine a world where energy costs a fraction of what it does now, and its production does not result in the destruction of our planet. Even better, we can continue on like this for millions of years ⏳
This is the world we can create if we crack nuclear fusion.
I Don’t Like the Sound of “Nuclear”
The word “nuclear” has so many negative connotations in society. We associate it (rightly) with nuclear weapons, radioactive waste, and huge disasters. Yeah, scary 😰
But this isn’t the entire story of nuclear energy. We are way more exposed to negative news than positive, and this is no different here. We hear about the disasters and the waste and the weapons, but we don’t hear about how it supplies almost 20% of our energy 😲
Plus, that is nuclear fission, not nuclear fusion.
Wait, What’s the Difference?
Nuclear
First, we need to understand what nuclear actually means. Nuclear is not a synonym with toxic waste, explosions, or danger. Nuclear is simply an adjective that relates to the nucleus of an atom ⚛️
Nuclear Fission 🤯
Nuclear fission is two words, one of which we have already defined. Our understanding now rests on the second word: fission.
The Merriam-Webster Dictionary defines fission as “a splitting or breaking up into parts.” So, nuclear fission is the breaking apart of the nuclei of atoms, which results in the release of energy ⚡️
If you want to learn more about nuclear fission, check out this course by Lumen Learning.
Nuclear Fusion 🤝
The difference of nuclear fusion from nuclear fission comes in the second word: fusion. Fusion is basically the opposite of fission — it’s putting stuff together instead of breaking it apart 🥳
How Does Nuclear Fusion Work?
The Theory
Nuclear fusion is supposed to work by smashing together two hydrogen isotopes, Deuterium (Hydrogen-2) and Tritium (Hydrogen-3), to create a helium atom. This produces energy because the two atoms lose some mass when they merge, which is released as energy.
The problem is that atoms don’t like to merge. The protons in the nuclei have positive charges, and they’ll repel other protons. To get around this, we superheat up the atoms to at least 15 million degrees Celsius 🥵
When the atoms have that much energy, the nuclei can’t hold their electrons anymore, and the substance turns to plasma, the fourth state of matter.
Because the nuclei are so energized and there aren’t electrons in the way, they smash into each other with enough force to overcome the natural repulsion of the two protons. The combination of Deuterium and Tritium has three neutrons, so one is thrown out at high speed, carrying a ton of energy 💥
A Complication… A Big One
It turns out that it’s really hard to heat a substance to 15 million degrees Celsius. Like, really hard. It’s so hard that I wonder why we even came up with this idea 🤔
Well, we are copying the sun. Nuclear fusion is the reason why the sun emits so much energy, but the sun has it a lot easier than we do. It’s massive, which means that the gravitational force alone is enough to get its core to such high temperatures.
Basically, we have to make a sun on Earth. If we can do this effectively, we can drive down prices of electricity because of the almost infinite amount of fuel we have. Since we don’t have nearly enough mass to create the same gravitational impact as the sun, we have to get creative 🤖
Machinery
As hard as it is to get these temperatures, we have done it (humans are all about doing the almost impossible 😉). It does require ingenious engineering, though. There are two main designs for fusion reactors that sort of work.
Magnetic Confinement Fusion 🧲
Magnetic confinement fusion uses magnetic fields to exert enough force on the atoms that they twist into a plasma stream. The design is called a tokamak, which is a Russian acronym for “toroidal chamber with axial magnetic field” 😑
…What?
All that means is that it’s a donut-shaped chamber with a magnetic field that causes charged particles to move around at super high speeds 🍩
This doesn’t completely work, though. The neutrons that get shot out damage the walls that contain the plasma, which turns into a big problem when it builds up. Also, it’s hard to sustain the plasma — the magnets only work for small amounts of time, which is not helpful ☹️
One project paving the way for the use of magnetic confinement fusion is ITER, an international ongoing project that has been working on a reactor for 35 years.
Inertial Confinement Fusion 🔦
Inertial confinement fusion uses a different shape than its magnetic counterpart. There is a shell with a vacuum chamber inside, and a hydrogen fuel pellet is placed inside.
Then a bunch of lasers are shot through lenses aimed directly at the pellet. Cool, right? 😎
This design also has its drawbacks, although they’re a bit different than those of the magnetic design. The major problem is that it does not break even on energy production vs energy consumption. To get this many strong lasers going takes a huge amount of energy, and so far it is more than the energy we get from the fusion. We want to gain energy, not deplete it.
Startups to Watch Out For
General Fusion
General Fusion is a Canadian startup that is developing a hybrid model called Magnetized Target Fusion. One of their main advancements is their use of a liquid metal wall that performs a double function. First, it is pumped to create a vortex to help contain the plasma. Second, it captures the energy from the fusion without harm to the solid outer wall.
Helion Energy
Helion Energy is an American startup that is using a hybrid model called Field Reversed Configuration. Their reactor produces Helium-3 using only Deuterium, which is found in water. Helium-3 is a rare gas used in quantum computing and medical imaging, which had only been found in nuclear fission and outer space.
First Light Fusion
First Light Fusion is a British startup focusing on harnessing the instabilities that most try to avoid in fusion. They use inertial confinement fusion and have worked with the complexities of instabilities from the start. One approach they are researching sends a shock wave to a gas-filled cavity, which makes an asymmetric collapse.
🔑 Takeaways
- Nuclear ≠ destructive
- Nuclear fission splits the nuclei of atoms 🤯
- Nuclear fusion combines the nuclei of atoms 🤝
- For nuclear fusion to work, we need to heat it up to 15 million degrees celsius 🥵
- Magnetic confinement fusion uses magnets to fuse atoms 🧲
- Inertial confinement fusion uses lasers to fuse atoms 🔦
- Three startups to watch out for: General Fusion, Helion Energy, and First Light Fusion
