Nuclear fusion is a nuclear reaction in which two or more atomic nuclei such as Hydrogen or the isotope of Hydrogen (Helium) combine very close together and then collide at an extremely high speed to produce heavier atoms and energy. This type of reaction has not been commercially developed and only occurs in the sun and other stars in space.
Nuclear fission is the process in which large atoms such as Uranium or Plutonium are split apart when they are excessively exposed to