Nuclear fission

Nuclear fission is the process by which a large nucleus is split into two smaller nuclei.

The fission of a nucleus releases an enormous amount of energy, which can be harnessed in a nuclear reactor to generate electrical power. Nuclear fission can also be used in a destructive fashion, such as in a nuclear weapon. Fission also releases neutrons which can then impact and cause other nuclei to split, causing a chain reaction. The two most common fissile elemnts used in nuclear power applications and weapons applications are uranium 235 and plutonium 239.

A critical mass of the right radioactive material is required to begin this chain reaction. Once a critical mass of the proper radioactive material of good enough purity is acheived, the crhain reaction begins.