What type of nuclear reaction is responsible for the liberation of energy:

(a) In a nuclear reactor?

(b) In the sun?

a) Nuclear fission-Nuclear fission is a process where the nucleus of an atom is split into two or more smaller nuclei, known as fission products.

b) Nuclear fusion-nuclear fusion is a reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles.