This category is related to the technological and safety aspects of the production of useful energy released by the fission of heavy nucleus.
In the nuclear fission process, the nucleus of an atom splits into two smaller atoms (fission products). This occurs naturally in radioactive elements (radioactive decay), but it can be induced artificially by making fissionable atoms absorb free neutrons.
This causes the nucleus to become unstable and makes it split apart. The fission process yields two smaller atoms, energy and several fast neutrons. Therefore, under certain conditions, the reaction can become self sustaining. This is called a chain reaction, or nuclear criticality.
A nuclear reactor is an apparatus in which nuclear fission chain reactions are initiated, controlled, and sustained at a steady rate.