Nuclear reaction

A nuclear reaction is a phenomenon in which atomic nuclei are transformed by the action of particles (neutrons, protons, deuterons, etc.), or by α, β and γ radiation.

This process occurs spontaneously in the nuclei of natural or artificial radioactive substances, but can be caused artificially by bombarding the atomic nucleus with particles or radiation.

Commonly there are considered to be two types of reaction caused by bombarding the nucleus: fission and fusion.