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What is Nuclear Fusion?

by Tin Lok Wu Americas Europe Jan 18th 20236 mins
What is Nuclear Fusion?

The Joint European Torus (JET), the largest tokamak (a powerful magnetic field to confine plasma in the shape of a torus) located in Oxfordshire, is a machine that produces energy by controlling nuclear fusion. It recently had a breakthrough in an experiment by producing 59 megajoules of electricity in five seconds, doubling the previous record in 1997 and setting a milestone in the history of the development of nuclear fusion-related technologies. The recent breakthrough shows that we are one step closer to commercialising the production of energy with nuclear fusion, a thought relatively “utopian” back in the day, and potentially having a new, sustainable energy source. In this article, we explore what nuclear fusion is and analyse why it’s important to invest more time and resources in scaling up this technology.

Nuclear Fusion Vs Nuclear Fission

The world is relatively familiar with the concept of nuclear fission, which is known to be the reaction necessary to produce nuclear energy. Nuclear fission is the process during which the nucleus of an atom is split into multiple smaller and lighter nuclei and generates energy. On the other hand, nuclear fusion is a relatively new concept, confined largely among the scientific community as it is yet to be a commercialised method of producing nuclear energy. In a nutshell, nuclear fusion is the exact opposite of nuclear fission; instead of splitting up, multiple smaller and lighter nuclei such as hydrogen are combined to form a heavier nucleus such as helium, which produces significant energy during the process. In other words, nuclear fusion generates energy by combining nuclei instead of splitting it up. 

When forcing the nuclei to combine, they experience a repulsion under the law of electrostatic force. To conquer the repulsion of the nuclei, the nuclei must be in the form of plasma, the fourth state of matter after solid, liquid, and gas. And to create plasma, you need an environment with extremely high temperature, extremely high density, and/or extremely high pressure; an environment much like the core of the sun.

The Endeavour of Manipulating Fusion

Today, scientists have found two ways to fuse nuclei. The first is called a magnetic confinement fusion. JET is one of the examples which adopt this method to generate nuclear fusion energy. As mentioned, an extremely hot temperature is required to trigger fusion. Inside JET, the plasma must be at least heated above 150 million degrees Celsius to realise fusion. However, there is currently no material in the world that can handle this temperature without getting damaged. To solve this, scientists have figured out a method to keep the plasma away from the walls of the device by employing an enormous magnetic field to confine the movement of plasma. Arguably the most efficient magnetic configuration is the tokamak, a doughnut-shaped toroid in which the magnetic field is curved around to form a closed loop.

Another method to fuse nuclei is inertial confinement fusion. The National Ignition Facility located in California in the US is the most advanced device that experiments with inertial confinement fusion. This method is relatively straightforward; it triggers fusion by rapidly compressing and heating the fuel to make it hot and dense enough to overcome the repulsion of the nuclei and fuse, usually with the help of a high-powered laser beam.

what is nuclear fusion Preamplifer at the National Ignition Facility. Image by: Wikimedia Commons

Why is Nuclear Fusion Considered “Utopian”?

1. Nuclear Fusion Is Clean

No greenhouse gases or air pollution are emitted during nuclear fusion. The major by-product of  fusion is helium, a non-toxic inert gas. Helium is, on the contrary, a very useful chemical element of which the supply is in shortage. It is widely used in the aerospace and cryogenics industries. If it can be collected during fusion, it will be another derived benefit. Although some nuclear waste will be produced in the process of fusion, its radioactivity is much weaker and lasts much shorter than nuclear waste produced during nuclear fission. For waste produced from conventional nuclear reactors, radioactive decay can take anywhere from 1,000 to 10,000 years. Yet, the activity of waste from nuclear fusion quickly declines in 100 years.

2. Nuclear Fusion Is Sustainable

It is arguably the most sustainable method of producing energy. Most nuclear fusion research is currently dedicated to deuterium-tritium fuel. Deuterium is an isotope of hydrogen that can be found in abundance in seawater while tritium is another isotope of hydrogen that is both rare and radioactive. Yet, scientists have figured out a way to produce tritium manually, in a sustainable manner. It has been found that by adding a layer made with lithium surrounding the reactor, it will produce tritium as a by-product during nuclear fusion. Lithium is the 33rd most abundant chemical element on Earth, widely distributed in trace amounts in soils, and is often used in the production of batteries in electric vehicles; its abundance can ensure nuclear fusion’s sustainable energy production. In addition, the fuel required in nuclear fusion is so little that one gallon of seawater can produce as much energy as 300 gallons of gasoline if we can fully manipulate it.

3. Nuclear Fusion Is Safe

The concept of building a sun on Earth might seem dangerous. But on the contrary, nuclear fusion is one of the safest methods to produce energy. As nuclear fusion does not involve a chained reaction like nuclear fission, the plasma will simply expand, cool down, and stop eventually if the confinement fails. It will therefore not explode in any circumstance and lead to catastrophic nuclear disasters due to either environmental reasons, military actions, or terrorism. It does not possess the risk of nuclear proliferation either, as materials required to make nuclear warheads like uranium will not be found in these reactors.

The Future of Nuclear Fusion

Despite all the benefits, what’s the catch? Nuclear fusion is still underdeveloped at the moment. In order to create fusion, the fuel is required to be heated to at least a hundred million degrees Celsius. The energy spent on maintaining the reaction is far more than the energy produced by the energy. For example, JET needs 24 megawatts of input to create 16 megawatts of output. 

Nobody can ensure that nuclear fusion can be commercialised in a short period of time, and the cost of creating nuclear fusion and the power plant remains to be incredibly expensive. International Thermonuclear Experimental Reactor (ITER), an international project working fusion, is located in Saint-Paul-lez-Durance, France. Its construction started in 2007 and is expected to have its first plasma in late 2025, The design and construction of it cost at least USD$22 billion. While the extremely high costs are a result of underdevelopment, critics of nuclear fusion describe ITER as a “white elephant” and claim that it is better to spend money on the development of renewable energy that is already proven to be successful.

However, we should not give up on any potential alternatives to achieve sustainable energy, as every notable method of producing energy had been expensive before it was commercialised. What’s more, in economics, there is a term called the law of diminishing marginal returns, which means that an additional factor of production will eventually result in a smaller increase in output after reaching the optimal level of production. Many resources are already given to the development of renewable energy, but we are at a bottleneck. Resources should be allocated to multiple projects at the same time to minimise the risk of one failing. All eyes are on ITER in determining whether nuclear fusion remains to be a utopian fiction or the future of energy production.

Featured image by : Wikimedia Commons

You might also like: The Advantages and Disadvantages of Nuclear Energy


About the Author

Tin Lok Wu

Currently an undergraduate of European Studies at the Hong Kong Baptist University and about to pursue a master’s degree in Political Science at Sciences Po Lyon, Tin Lok is interested in researching environmental issues from a relatively conservative perspective, hoping to incorporate the voices of everybody on the political spectrum into the debate.

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