The table below lists the major differences between fusion and fission reactions.
|Nuclear Fission||Nuclear Fusion|
|Nuclear fission is a nuclear reaction that splits a heavy atom into two or more smaller ones.||Nuclear fusion is a nuclear reaction that combines two or more small atoms to form a large atom.|
|It does not occur naturally.||The universe is full of instances of nuclear fusion reactions. Every star uses it to produce energy.|
|It produces a large quantity of energy.||It produces greater energy than the fission reaction.|
|Does not require a lot of energy to split an atom into two.||Requires a lot of heat and pressure for the process to happen.|