* This article is the first in a series of installments examining the potential of different energy initiatives and types.
If you’re reading this article, chances are, you’re living in a first-world country. You probably have access to modern technology, whether it be your cell phone, laptop, or even central heating system.
Not everyone has access to these types of things. If fact, an estimated 16% of the world (that’s 1.2 BILLION people) have little or no access to electricity. Try to imagine your life without power. Our lifestyles make this inquiry hard to even think about. That’s what hundreds of millions of people deal with every day. However, there’s no point in whining about an issue and not doing anything. So, how do we solve this crisis? There are many answers, however, one idea sticks out from the rest: Nuclear Fusion.
Wait… What is Nuclear Fusion?
To put it simply, nuclear fusion is a process that references the amalgamation of two or more light atomic nuclei into one different, heavier atomic nucleus with a large release of energy.
On the sun, nuclear fusion is constantly occurring, with heaps upon heaps of energy produced. The conditions and gravitational pull are perfect for creating such reactions, however, on Earth, they much harder to achieve. If we do obtain this energy source, we could potentially have access to an almost limitless energy resevior.
Great! So, How Exactly Does Nuclear Fusion Work?
Before we can get into the ins and outs of nuclear fusion, we first need to understand what an atom is.
An atom contains two main commodities, a nucleus and subatomic particles. The nucleus is where a split or merge can occur. Nuclei contain two of the three subatomic particles, protons (which are positively charged) and neutrons (which have no charge). It is important to note that this results in the atomic nucleus being positively charged. Around the positively charged nucleus orbit electrons, which are negatively charged. Nuclear fusion only works with ‘small’ atoms, such as hydrogen. In this scenario, only one proton is present in the pre-fusion atom. This means that when another proton tries to coalesce with the atom, the pressure is overwhelming, and the two protons try to repel one another. Since this process is referencing atomic nuclei, this interaction is referred to as the coulomb force. This was formed on the basis of Coulomb’s law, in which electrical force is proportionate to the inverse of the square of the distance (of the gravitational force). This force tries to prevent the interaction of protons.
When the two protons come close together, they may amalgamate into a new atomic nucleus as a result of strong interactions. Now you may be thinking; surely you require a lot of nuclear fusion in order to do anything significant! I’m here to tell you, you thought incorrectly. Nuclear fusion produces an overwhelmingly high amount of energy, but, don’t take my word for it, take this example instead: It would only take 1 gram of fuel (the hydrogen isotopes of deuterium tritium) to equal the amount of energy produced by 12 000 KILOGRAMS OF HARD COAL!
Typically, it is not possible to achieve nuclear fusion, as the strongly repulsive electrostatic forces between the positively charged nuclei prevent them from getting close enough together to collide and for fusion to occur. However, this does not always occur. If the nuclei can come into close range with one another, and ignore other electrostatic forces, then the attractive nuclear force (the force that binds and amalgamates protons and neutrons in atomic nuclei) between the nuclei will outweigh the repulsive (electrostatic) force, allowing the nuclei to fuse together.
But how do we ignore Coulomb’s force and allow fusion to occur? HEAT and PRESSURE (The more pressure that is available, the less heat that is needed). These two factors work together to increase the speed at which nuclei interact, eventually leading to two atomic nuclei hitting eachother and BAM! The protons no longer repel each other and amalgamate into a new nucleus.
Now that seems simple enough, however, on Earth, we would require a heat level of 150 million degrees Celsius for this process to occur (due to the lack of pressure we have), which is hard to achieve 🙁. Current ideas, however, offer solutions, and will be discussed in the next few sections of this article. In summary:
Nuclear Fusion is the process of taking two light atomic nuclei (i.e. Hydrogen Isotopes) and using heat and pressure in order to make a heavier atomic nucleus (i.e. Helium)
Making Nuclear Fusion a Reality
As of currently, there are no economically or socially feasible techniques that will effectively result in nuclear fusion however, this does not mean that individuals are ignoring this energy type. In fact, a myriad of individuals have brought forward ideas and techniques that aim to make fusion possible!
Fusion Fuel and Tech (General)
Current technology makes achieving fusion between the hydrogen isotopes of deuterium tritium through the use of a reactor most feasible. A D-T fusion reaction on average releases over four times as much energy as the fission of uranium (on a mass basis, specifically 17.6 Mega Electron-Volts). The objective of these reactors is to take the neutrons generated from the D-T fusion and absorb them into a layer of lithium (which should be at least 1 meter in thickness) surrounding the core. The Lithium transforms into tritium (which fuels the reactor) and helium. The layering will slow down the high energy (approx. 14 MeV) neutrons and allow their energy to be absorbed, resulting in the generation of heat. This energy will be collected by coolant (such as Li-Pb eutectic or water) and used to produce energy. If inadequate tritium is produced, supplementary resources must be enacted upon.
ITER (International Thermonuclear Experimental Reactor)
ITER is an internationally acclaimed project with the aim of producing controlled nuclear fusion reactions to produce energy. It’s main objective currently, is to generate heat, not electricity, however, if it is able to produce more energy than it consumes, that is, if it works, then ITER could provide energy to generate electricity in environmentally-friendly production plants.
ITER hosts the reactions inside a tokamak, a device that uses magnetic fields to hold plasma in the shape of a torus. In this structure, D-T nuclei fuse to form Helium, gaining mass and generating energy, which is then carried away by neutrons, striking the walls of the tokamak.
Inertial and Magnetic Confinement
There are two primary branches of the generation of thermonuclear nuclear fusion power; inertial and magnetic confinement. The majority of fusion research centers around magnetic confinement, including the ITER project, however, inertial confinement brings promise as well.
What exactly do either of those terms mean?
Inertial confinement focuses on applying a monumental amount of energy to a minuscule pellet of D-T and allowing it to implode until fusion is achieved. This process starts off by symmetrically applying energy to the surface of a fuel pellet (containing deuterium and tritium gas) that is surrounded by a thin coating containing ‘heavy’ atoms. (See step 1 in the diagram below). The heat and pressure from this event result in the vaporization of the outer layer, blasting outwards (step 2). The reaction forces form shockwaves that travel inwardly, allowing for the implosion of the pellet as a result of the compression of its core (step 3). Finally, the pellet undergoes fusion, leading to the release of thermonuclear heat (step 4). Ignition occurs as a result of heat travelling from the inward layers outwards.
As of 2019, there are two cardinal methods of applying energy onto a pellet: direct drive and indirect drive. Direct drive, as the name suggests, focuses around applying energy directly to the pellet. This method is generally more efficient than indirect drive, however, suffers from asymmetry problems as a result of the nature of lasers. Indirect drive suspends the pellet in a heated hohlraum, a cylindrical container typically made from gold. This method is less efficient than direct drive as a result of the absorption and fractional transmission of incident energy.
Magnetic confinement is a much more popular approach in terms of the thermonuclear scene. This technique takes vast quantities of D-T plasma with a density of less than a milligram per cubic metre and confines it to a magnetic field. The atmosphere allows heat and pressure to produce a fusion temperature. This method is ideal as magnetic fields can confine plasma due to the electrical charges on separated ions and electrons being able to follow magnetic field lines. This also helps prevent particles from entering reactor walls, as when that occurs fusion is stalled or stopped. The most effective way of achieving this is through torodial-based magnetic configurations (i.e. tokamaks, stellarators and reversed field pinch (RFP) devices) with poloidal fields superimposed amongst them. This results in the confinement and control of plasma.
Why does Nuclear Fusion Even Matter?
Now, this whole process sounds complicated, and it is. However, nuclear fusion is essential to continue to pursue and if achieved, will help our society advance into a type I civilization, in regards to the Kardashev Scale (Meaning we can harness all the energy from our planet, our current rating being 0.73/1. *The energy disposal level of this type of civilization would be 10¹^⁶W). The world DOES NOT have enough resources and health left to continue pursuing fossil fuels, and nuclear fusion provides a clean and almost infinite opportunity. Just like the amount of energy it can provide, the applications of nuclear fusion energy are also almost infinite.
Nuclear Fusion: The Good, The Bad, and The Dirty
Nuclear Fusion has the potential to provide society with an infinite energy reservoir, however, that does not mean that it is easy to achieve, or that it doesn’t come with any cons.
CLEAN ENERGY. This is a huge factor in why it is so essential to pursue the study of nuclear fusion techniques. As fossil fuels continue to negatively impact the Earth, more and more attention is being brought forward to alternative energy solutions. This energy method leaves no greenhouse gases and allows for us to help power the world with environmental stability in mind. In addition, this technique leaves behind little to no nuclear waste! The energy density of nuclear fusion is approximately 10 MILLION times that of fossil fuels.
A LIMITLESS RESEVOIR. It’s safe to say that the only people who like fossil fuels are the ones who run companies that rely on them. However, they are non-renewable resources that not only hurt our planet but, are also unsustainable. This is where nuclear fusion comes in. The two primary components of this process are deuterium, which can be created through the distillation of seawater and tritium, which can be produced inside a reactor, meaning that the two primary compounds are easy to access and replenish.
CONTROL. Nuclear fusion is a technique that unlike fission, is decently easy to control or stop. This is especially useful when dealing with energy and other high-power substances.
ECONOMIC INSUFFICIENCY. Currently, it is not economically viable to consistently produce nuclear fusion-based reactions. The complexity of the devices, when combined with the time and effort required to produce a successful reaction leads to some heavy bills. However, by continuing to pursue the study of nuclear fusion and allowing it to enter commercialization, we are paving the way for a cheap and cost-competitive resource. ITER (International Thermonuclear Experimental Reactor), a large-scale international Nuclear Fusion Project estimates that completing the reactor will use approximately $22 billion Euros. Whilst various governments contribute differently, the American government only gave around $120 million, half of what would be considered optimal. However, considering that the U.S spent over $500 billion on the military in 2015, this is a relatively small price to pay for the future of energy. In addition, once fusion energy is made viable, it will become cheaper to produce and use.
OUT OF REACH. Nuclear fusion is a highly complex area of study that is simply not yet ready to be commercialized and used internationally. Currently, it takes an overwhelming amount of physical and economic resources to create a small-scale reaction for just a short period of time. However, the only way to put this energy form into our personal orbits is by continuing to pursue it’s study and analyzing it.
I hope you learned something from this article and agree that the pursuit of nuclear fusion energy is necessary. The one thing that I believe everyone should take away from this article is nuclear fusion provides us with the ability to give energy to everyone, something that should be a basic human right, in an environmentally manageable way. Thank you for reading!
Further Reading and Sources
If you found this topic to be of interest, or wish to look further into nuclear fusion, check out these links!