#15: Nuclear Fusion: The Solution?
Welcome back!
Today, we’ve got a rather interesting topic. Instead of writing about some new-fangled technological advancement in the field of energy, or discussing the economic incentives of putting solar panels on your house, I’m going to be exploring something a little weird. So, nuclear fusion has been something that’s in the works for a century or so, and something that’s always been reported to be ‘just a few years down the road’, though that clearly hasn’t been the case. So, is nuclear fusion the solution? Is it actually feasible? Today, we find out.
So, almost everyone has heard of nuclear power. You know, those big facilities, that almost melted down in Japan a few years ago, and caused the abandonment of an entire city in Russia?
Yeah, I thought so. Everyone knows what nuclear energy is. However, something a lot of people don’t know is that there are different types of nuclear energy: nuclear fission and fusion. Now, I know that this article is meant to be about nuclear fusion, but I feel that to understand this topic better, it’s important to dip our toe into the fission world for a second. So, let’s do that.
Nuclear Fission
So, what is nuclear fission? Well, this is the type of nuclear energy that we can actually use these days. Fusion is only kinda-sorta possible at the moment, but we’ll get to that later.
Fission, in brief, is essentially turning one big thing into two small things to create energy. Let’s consider an analogy. If you shoot a balloon with a gun, what’s gonna happen? Energy is released, right? Yeah, it is, in the form of sound waves. Okay, so that’s cool.
Well, turns out, that’s the same thing that happens in fission reactions. You shoot a neutron at a much larger atom, causing it to split into two smaller (but still large) atoms. This shooting process ends up creating energy, as seen in the diagram below.
It’s worth noting though that our analogy doesn’t perfectly match the situation in this case. While it probably took more energy to fire the bullet than the energy released by the balloon when it popped, in the case of fission, the energy released usually ends up being greater than the initial energy of the neutron fired. I’m kind of oversimplifying the process here, but again, this article isn’t about fission: we’re just dipping our toe in.
Typically a fission reaction will have the following equation:
It’s just a large atom (like Uranium-235) being broken down. I should also point out that the large atom needs to be a bit unstable for this to work. If it’s not, the neutron will just bounce off and go in the opposite direction.
But anyway, you get the gist. One big object gets shot by a neutron and gives us energy plus two smaller (but still large) objects. Got it, got it?
Why is this important? Well, because nuclear fusion is, as the name indicates, pretty much the exact opposite, except it’s carried out with much smaller atoms. Confused? Let me explain.
Nuclear Fusion
So, just like nuclear fission is the process of taking it a big thing and turning it into two, fusion is the process of combining two smaller atoms into one larger one. Just like how clapping your hands together ends up releasing energy, this does so too.
So, why is nuclear fusion important? Well, as it turns out, it’s the process the sun actually uses to produce energy. As Elon Musk once put it, “we have a huge nuclear fusion reactor in the sky.” In this sense, it’s understandable why fusion is often looked forward to as the ultimate solution to all of our energy needs: instead of needing to rely on the fusion process in the sun, we could have our very own down here on Earth. Obviously, it wouldn’t be nearly as powerful, but still….
So, the natural question to ask now is….how does fusion actually work. Just like fission, it can very easily be represented by a diagram. Check out the one below for instance.
The most common fusion reaction that scientists and engineers are currently trying to make happen is between atoms of deuterium and tritium, which are isotopes of hydrogen. This means that, just like regular hydrogen, they’ve only got one proton. However, unlike a normal atom of hydrogen, neither have a mass of one. This is the reaction shown above.
You see, deuterium has an extra neutron added on top of the proton it already had, for a total of two nucleons. Tritium, adds two neutrons to the plain hydrogen atom, for a total of three nucleons. When you accelerate these two atoms into each other, it creates a fusion reaction. Energy is released, along with a helium atom (which is stable), as well as a spare neutron. The reaction is given as follows.
But how is energy actually produced? Well, here is where we start to get more into the physics. You all know this equation, right?
Well, this equation simply tells us that energy is proportional to mass. From this, we know if there is a difference in the masses of the products of the reactants, there must either be excess energy needed for the reaction to take place, or excess energy released after the reaction. As it turns out, the products of a fusion reaction always end up weighing less than the reactants, meaning that energy equivalent to the mass, must be released each time.
Okay, so now that we know how fusion actually works, we need to ask ourselves an important question: is it actually the solution to all of our energy problems? Well, to be honest, we don’t know. I mean, although scientists and engineers have been able to make fusion reactors work (actually, a teenager did it in his own garage), the current fusion systems need more energy to get the reaction going than the energy released by the reaction itself.
So, in that sense, while nuclear fusion would be great for the environment, and having it would mean that we could provide energy at a very low price, making it more accessible and completely clean, fusion is still heavily in the works.
Thank you for reading! Hope you enjoyed! Today, we tried to take a more scientific, physical approach to understanding, more theoretical than engineering. Although I enjoy the whole hands-on process more, I will continue to do these theory pieces every once in a while. If you’re interested in my hands-on work, feel free to check out my website, ModelED! Until next time…see ya!
