Difference between Fission and Fusion

Fission vs. Fusion

What is difference between fission and fusion? The two types of nuclear reactions used to produce energy are fission and fusion. Both reactions present their differences and then we will explain. Below this post is all about the difference between fission and fusion.

Difference between Fission and Fusion


This type of nuclear reaction occurs when the heavy nucleus of an atom separates or divides. It occurs by radioactive decay or by bombardment of subatomic particles known as “neutrons”. Under unusual circumstances, produced neutrons can divide more nuclei of atoms; thus creating a rapid chain reaction. It is very common for nuclear power plants to exploit the fission process.


Nuclear fusion is a process in which the nuclei of atoms come together, that is, they “merge.” To achieve this, it is necessary to achieve extremely high energy levels and the temperature required for this task is millions of degrees.

This reaction also releases a lot of energy and is the one that occurs in the sun. Nuclear fusion is a stronger reaction than fission.

Key Differences between Fission and Fusion

  • When a fission occurs, the heavy nucleus of the atom is divided, whereas in the case of fusion the nuclei of the atoms join.
  • Some elements with which nuclear fissions are usually produced are: uranium, strontium and krypton.
  • Some elements with which fusions are usually caused are: hydrogen and helium.