Nuclear fusion and nuclear Fission: In this Post, we will discuss the basic difference between these two reactions. Nuclear fission and fusion involves the disintegration and combination of the element nucleus.
In the case of nuclear fission, an atom divides into two or more smaller or lighter atoms, while in case of a nuclear fusion occurs when two or more atoms join together or fuse together to form a large or heavier atoms.

Nuclear Fusion and Nuclear Fission Difference
The first difference between the nuclear fission and fusion nuclear fission when the nucleus of an atom split into two or more smaller or lighter atoms through a nuclear reaction, the process is to mass nuclear fission reaction.
While in case of a nuclear fusion, nuclear fusion is a reaction through which two or more light and nuclei collides with each other to form a heavier nucleus.
In case of a nuclear fission, when each atom splits, a tremendous amount of energy is release, while in case of a nuclear fusion. The energy released during the nuclear fusion is several times greater than the energy released during nuclear fission process.
Fusion reactions do not occur naturally, while fusion reaction occurs in the stars and sun. The another difference between the nuclear fission and fusion reaction. Comparatively, less energy is needed to split an atom in a fusion reaction.
While in case of a nuclear fusion reaction, high energy is needed to fuse two or more atoms together in a fusion reaction. Atomic bomb. Works on a principle of nuclear fission and a nuclear reactor. It is also the example of nuclear fission reaction.
There are two types of nuclear fission reaction, control chain reaction and uncontrolled chain reaction. So a nuclear power plant or we can say nuclear reactor. It is an example of control chain reaction while atomic bomb. It is an example of uncontrolled chain reaction.
Hydrogen bomb works on the principle of nuclear fusion so that the sun occurs in the sun. Stars and hydrogen bombs are the example of the nuclear fusion reaction. So these are the basic difference between the nuclear fission and fusion reaction.