nuclear fission and fusion difference - Overview, Structure, Properties & Uses

Nuclear Fission and Fusion Difference - A Complete Guide

Edited By Team Careers360 | Updated on Jun 02, 2022 11:54 AM IST

Type of reaction where two or more atomic nuclei combine to form a different atomic is called nuclear fusion while Nuclear fission is the process where heavier items get split into smaller nuclei. And by the fission process, a very large amount of energy and photons are released.

Nuclear fusion produces nuclei heavier than the parent nuclei and releases energy upon their formation. Upon the fusion of lighter nuclei, they release energy therefore it is an exothermic reaction. While when the fusion of heavier nuclei is taking place energy is accepted so the resulting reaction can be called endothermic. This means lighter elements like helium, and hydrogen are more suitable for a fusion reaction while that heavier elements like uranium, thorium, and plutonium are more suitable for a fissionable reaction. So we can conclude that fission and fusion are two chemical processes where a tremendous amount of energy is released. Before going to discuss this topic in detail we need to discuss the nucleus.

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Nuclear fission
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Difference between nuclear fission and nuclear fusion or Fission vs fusion

A nucleus is made up of protons and neutrons and is the basis of nuclear science. Both fission and fusion involve the dispersal and the combination of the nucleus so these two processes are a part of nuclear science. A very important term associated with the fission and fusion process is nuclear binding energy and it is the energy that is required to keep the neutrons and protons in a nucleus. The total mass of individual protons and neutrons is always greater than the mass of elements in the nucleus and the difference in mass can be defined with the help of nuclear binding energy. So nuclear binding energy can also be defined as the missing mass or mass defect or can also be referred to as the mass released.

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Nuclear fission

The splitting up of a heavier nucleus into lighter nuclei is called nuclear fission. Nuclear fission was discovered by the German scientist Otto Hahn, Lise Meitner, and Fritz Strassmann in 1938. By bombarding uranium with neutrons a new element that is a lighter element such as barium was formed after the reaction. The following image shows the formation of barium from the uranium 235 binary fission process.

Nuclear fission

By observing the resulting product we got that nucleus divided asymmetrically. And the product obtained varies with very reaction conditions. And by observing the reaction more than one neutron is produced as a byproduct. These neutrons are produced as a byproduct can also induce another fission reaction there by a nuclear chain reaction is formed. This means that the fission of Uranium-235 releases three neutrons per fission so this neutron can also be absorbed by other uranium-235 nucleus and the rate of fission will increase rapidly. A particular mass is required for performing this reaction which means that the mass of neutrons is low it will be escaped and cannot be captured for inducing efficient reaction and the minimum mass required for a sustainable fission reaction is called the critical mass. The enormous amount of energy released during the nuclear chain reaction has much application in the industrial field.

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Nuclear fusion

The reaction where two nuclei are combined to form a heavier one is called a nuclear fusion and a stable nucleus is formed. This type of reaction is just the opposite of the nuclear fission reaction. When two nuclei that are participating in a reaction have enough kinetic energy to overcome their electrostatic repulsion they will fuse together and a nuclear fusion reaction will occur. Fusion reactions are highly exothermic in nature for a lighter nucleus. Let us take some of the nuclear fusion reactions where two deuterium atoms combine to form helium with mass number 3 it is also called deuterium-deuterium fusion. The below reaction shows the formation of helium from the material deuterium fusion. Deuterium and tritium atoms undergo fusion reactions to produce the same helium atom but with the mass number 4. The hydrogen bomb is an example of a fusion reaction and it creates a very high temperature. The nuclear fusion reaction is the power source for stars including the Sun. The following image shows a nuclear fission reaction.

Hydrogen Nuclear Fusion Chemistry - Free image on Pixabay

For determining the energy released upon Nuclear fission and fusion reaction we use Einstein's equation that is E=mc². Where m is mass in Kg, c is the speed of light and E is the energy expressed in joules.

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Difference between nuclear fission and nuclear fusion or Fission vs fusion

The very important difference between fission and fusion reaction is that fusion is the combination of lighter nuclei for forming a heavier one while fission is the splitting of heavier nuclei for forming lighter nuclei. Both fission and fusion involve the release of a tremendous amount of energy. Nuclear fission reaction occurs when a heavier nucleus is bombarded with low-energy neutrons and which will further split into lighter nuclei. And nuclear fission reactions are used in nuclear power reactors and nuclear weapons to release a tremendous amount of energy. Both of them released a tremendous amount of energy but the energy released after a nuclear fusion reaction is much greater than nuclear fission. We haven't seen any naturally occurring fission reactions, only fusion reactions that are present in the stars and sun. For initiating a nuclear fission reaction a small amount of energy is needed while for a fusion reaction large energy is needed because it involves the fusion of two or more nuclei. All the atomic bombs work on the principle of nuclear fission while the hydrogen bomb works on nuclear fusion.

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Frequently Asked Question (FAQs)

1. What is the difference between fission and fusion?

Both Nuclear fission and fusion are used for the production of a tremendous amount of energy but there are some differences between them too. The division of a single nucleus into smaller nuclei is nuclear fission while the combining of two or more small nuclei to form a heavier one is called nuclear fission. A nuclear fission reaction to initiate small energy is required for a nuclear fusion reaction; a large amount of energy is required to combine these small nuclei for the formation of a heavier one. The amount of energy released during a nuclear fusion reaction is very much higher than that of a nuclear fission reaction.

2. Distinguish between nuclear fission and nuclear fusion?

The reactions that are used for the production of a tremendous amount of energy is called nuclear fission and fusion reaction. Fission and fusion reactions are different since for a fission reaction to proceed it requires a very small amount of energy and with that energy, heavier nuclei are split into lighter nuclei with the release of energy. A very common example of nuclear fission is the splitting of Uranium-235 for the formation of barium. While a nuclear fusion reaction is a reaction where the required a large amount of energy to fuse the small nuclei and thereby forming a large nucleus with a tremendous release of energy. A very common example of a nuclear fusion reaction is the combination of deuterium and tritium for the formation of helium with the mass number 4.

3. Write any two difference between nuclear fusion and nuclear fission?

Both nuclear fission and fusion involve energy release but there is some difference too.

For fission, it requires small energy while fusion requires a large amount of energy.
The energy released after fusion is higher than that of a fission reaction.

4. Define nuclear fission and fusion for example.

Nuclear fission means the splitting of atomic nuclei into smaller units whereas nuclear fusion is the binding of nuclei together.

Example for nuclear fission: Uranium atom splits into xenon, iodine, barium, etc.

Example for nuclear fusion: A Hydrogen nucleus fuses to form helium.

5. Nuclear fission can be explained by which model?

Nuclear fission is explained by the liquid drop model.