Nuclear fusion is the process by which two or more atomic nuclei come together to form a new nucleus and release a large sum of energy. This occurrence is most commonly seen in stars such as the sun.
Nuclear fusion was discovered in the early 20th century by Hans Bethe and Carl Friedrich von Weizsacker. Their theory shows in detail how stars generate large sums of energy by fusing hydrogen nuclei into helium. However, this technology was unsuccessful when repeated on Earth.
Nuclear Fusion And How It Works
Don’t worry, understanding fusion is not rocket science! Fusion simply works when two light nuclei merge to form a single heavier nucleus (see the diagram above). This merging process requires high temperatures of up to ten million degrees Celsius. Such heat allows these nuclei to merge while overpowering the natural charge repulsion from the like charges of electrons. The process releases energy and mass, because the mass of the heavier nuclei is less than the sum of the two small nuclei. Therefore, the loss of extra mass is converted into energy, in accordance to Einstein’s famous equation, e=mc².
Fusion reactions take place in a state of matter called the plasma. A plasma is a hot, charged gas made of positively charged ions and delocalized electrons, differing from the conventional properties of solids, liquids, and gasses.
Not only does fusion require high amounts of heat, but it also requires high amounts of pressure and a small amount of space. The nuclei must be confined to a small space to increase the chance of fusion and collision.
For example, the sun merges hydrogen and nuclei to perform its fusion effect. This is done efficiently by the hot plasma core in the center of the sun, as well as its immense gravity which creates extreme pressures.
Applications of Fusion
After the discovery of fusion back in the early 20th century, scientists have been attempting to recreate fusion on our planet by constructing reactors (see the diagram above). If fusion can be successfully replicated, it could provide unlimited, clean, and safe sources of energy for the global population. Due to the high amounts of energy obtained, fusion reactions can be 4 million times more efficient than the conventional burning of fossil fuels and greenhouse gasses. It can also generate 4 times more energy per kilogram of fuel than fission!
Nowadays, most large-scale reactors use deuterium and tritium (DT). Both are isotopes of hydrogen, which form helium when undergoing fusion. With only a few grams of these isotopes, terajoules of energy can be generated, providing enough energy for an individual for up to 6 years. Deuterium and tritium reactions (DT reactions) can also occur at lower temperatures and are more efficient to operate with.
Therefore, scientists have been working on harnessing nuclear fusion as a source of energy on Earth. Magnetic fields and electromagnetic forces have been used to contain the extremely hot plasmas needed for these fusion reactions. For example, the Tokamak (see the diagram below) is a donut-shaped reactor, confining the reactants to a very strong magnetic field powered by a solenoid, with a plasma containing electrical current.
Although there have been breakthroughs in the research of nuclear fusion, achieving a sustainable fusion reaction on Earth remains a challenge.
Fun Facts
Nuclear fusion can also be used for seawater desalination and the extraction of tertiary oil resources.
Nuclear fusion is not as limited as burning fossil fuels, which provides a greater beneficial alternative.
Nuclear fusion does not emit any harmful gasses like carbon dioxide and other greenhouse gasses.
Works Cited
Barbarino, M. (2022). What is Nuclear Fusion? [online] www.iaea.org. Available at: https://www.iaea.org/newscenter/news/what-is-nuclear-fusion.
BYJUS. (2023). Nuclear Fusion - Definition, Occurrence, Examples, Applications & FAQs. [online] Available at: https://byjus.com/physics/nuclear-fusion [Accessed 6 Mar. 2024].
EUROFusion (2023). History of Fusion. [online] EUROfusion. Available at: https://euro-fusion.org/fusion/history-of-fusion/.
ITER. (n.d.). Advantages of fusion. [online] Available at: https://www.iter.org/sci/Fusion.
Lanctot, M. (2022). DOE Explains...Nuclear Fusion Reactions. [online] Energy.gov. Available at: https://www.energy.gov/science/doe-explainsnuclear-fusion-reactions.
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