Nuclear fission
Process of radioactive decay in which nucleus of an atom splits into smaller, lighter nuclei. Fission releases very large amounts of energy and causes a nuclear chain reaction in nearby atoms. Fission rocket use fissionable fuel in order to produce codex:thermal power to the codex:reactor.
Fission can be controlled by adjusting proximity of the fuel. There are different approaches to control mechanisms:
* Control rods can be inserted between codex:fuel rods, inhabiting the chain reaction. * Fuel rods themselves can be moved away slowing down the reaction. * In codex:liquid core reactors, the fissile fuel itself can be pumped away the reaction chamber.
Current nuclear thermal rockets use either codex:uranium, codex:plutionium or codex:thorium as a fuel source.