Nuclear fission

Nuclear fission is a process where a large atomic nucleus (such as uranium) is split into smaller particles. A nuclear fission reaction releases millions of times the amount of energy as is released in a typical chemical reaction, making it an efficient source of energy.

For centuries, humanity has used nuclear fission for energy production through nuclear power, as well as nuclear weapons. Both uses are possible because certain substances, called nuclear fuels, undergo fission when struck by fission neutrons, and in turn emit neutrons when they break apart. This enables a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.

While fusion power and hydrogen fuel cells have been developed alongside traditional fission power, humanity continues to employ fission in auxiliary starship reactors and nuclear weaponry.