Answer
Nuclear fusion and nuclear fission are different types of reactions that release energy due to the presence of high-powered atomic bonds between particles found within a nucleus.
In fission, an atom is split into two or more smaller, lighter atoms. Fusion, in contrast, occurs when two or more smaller atoms fuse together, creating a larger, heavier atom.
Fission reaction does not normally occur in nature.But fusion occurs in stars, such as the sun.
Fission produces many highly radioactive particles.Few radioactive particles are produced by the fusion reaction, but if a fission "trigger" is used, radioactive particles will result from that.
A critical mass of the substance and high-speed neutrons are required in fission. In contrast, a high density, high-temperature environment is required in a fusion reaction.
In a fission reaction, it takes little energy to split two atoms. Extremely high energy is required to bring two or more protons close enough that nuclear forces overcome their electrostatic repulsion in a fusion reaction.
In terms of released energy, the energy released by fission is a million times greater than that released in chemical reactions; but lower than the energy released by nuclear fusion. On the other hand, the energy released by fusion is three to four times greater than the energy released by fission.
One class of nuclear weapons is a fission bomb, also known as an atomic bomb or atom bomb. One class of nuclear weapons is the hydrogen bomb, which uses a fission reaction to "trigger" a fusion reaction.
In terms of energy production, fission is used in nuclear power plants.While fusion is an experimental technology for producing power.
Finally, Uranium is the primary fuel used in nuclear power plants.Hydrogen isotopes (Deuterium and Tritium) are the primary fuel used in experimental fusion power plants.