A nuclear weapon (or nuke, nuclear warhead, nuclear bomb) is an explosive device that uses nuclear reactions, either fission (fission bomb) or from a combination of fission and fusion reactions (thermonuclear bomb). Both bomb types release large quantities of energy from relatively small amounts of matter.
Nuclear bombs have had yields between 10 tons and 50 megatons of TNT. Its weight to energy yield ratio is more than 1:1000. Potential gigaton yield devices are "doomsday bombs." One detonated about 16 kilometers up would start fires over an area of more than 700,000 square kilometers. A few 1000 gigatons would be enough to kill all humans.
Nuclear devices are weapons of mass destruction (WMD) or doomsday devices and can devastate entire cities by blast, fire, and radiation. Nuclear non-proliferation treaties have to be signed by Type 0 civilizations in order to prevent MAD (mutually assured destruction) in a futile nuclear war.
| Fission weapons | Also called atom bomb, atomic bomb, A-bomb. This first generation nuke uses fissile material, usually enriched uranium or plutonium. The amount of energy released by fission bombs can range from about 1 ton to over 500 kilotons of TNT. They are a serious form of radioactive contamination and nuclear fallout. |
| Fusion weapons | Also called thermonuclear weapon, hydrogen bomb, H-bombs. This second generation rely on fusion reactions between isotopes of hydrogen (deuterium and tritium). Fission reactions are used to trigger fusion reactions, and these fusion reactions can trigger additional fission reactions. The energy yield can be up to 50 megatons of TNT. Fusion reactions do not create fission products, and far less nuclear fallout, but due to the fission stages, can end up creating the same fallout as fission weapons. |
| Neutron bomb | A neutron bomb is a low-yield thermonuclear weapon designed to maximize lethal neutron radiation in the immediate vicinity of the blast while its neutron burst is able to penetrate enemy armor such as tanks more effectively than a conventional warhead. |
| Cobalt bomb | A cobalt bomb is designed to produce enhanced amounts of radioactive fallout, intended to contaminate a large area with radioactive material. A fission weapon's fallout decays much more rapidly than that of a cobalt bomb. A cobalt bomb's fallout would render affected areas stuck in fallout for decades. |
| Pure fusion weapon | A pure fusion weapon is a hydrogen bomb that does not need a fission "primary" explosive to ignite the fusion of deuterium and tritium. Due to its not requiring a fission primary explosive to initiate a fusion reaction, the pure fusion weapon also has greatly increased yield. Antimatter is alternative fusion trigger, mainly for antimatter-catalyzed nuclear pulse propulsion. |