Nuclear weapons developed by the Manhattan project for the Allies were Fission weapons called Atomic bombs.
Large scale Fusion weapons developed by Hungarian Edward Teller in USA after WW2 were called Hydrogen Bombs.
However during 1942 the Nazis developed a hybrid fusion boosted fission weapon, in which hollow charge explosives were used to cause a plasma pinch, a kind of flash of neutrons to ignite a Fission explosion.
Nuclear fusion has been used for nuclear transformation, which is the production of new materials by fusion, and for the type of specific type of transformation called nuclear synthesis, which is the production of materials not normally found in nature. It has been used in nuclear bombs, specifically fusion bombs or hydrogen bombs. There is hope that nuclear fusion can be used to provide power for generation of electricity, though this has not yet been achieved in a practical system. There is a link below to an article on nuclear fusion.
Up to now only in H-bombs. Experiments in fusion are on going though.
Nuclear fusion does not currently occur in nuclear plants. Nuclear plants use nuclear fission, where atoms are split to release energy. Fusion reactions, in which atomic nuclei combine to release energy, are not yet used commercially for electricity generation.
Nuclear bombs use nuclear fission of some heavy element, usually uranium or plutonium. Thermonuclear bombs use the detonation of a fission bomb to ignite the fusion of hydrogen. Such weapons are more powerful than ordinary nuclear weapons because nuclear fusion releases more energy than nuclear fission, and because the process of fusion itself can be used to ignite more fission.
Nuclear fusion and nuclear fission are two types of nuclear reactions that release energy. Fusion combines atomic nuclei to create heavier elements, while fission splits atomic nuclei into smaller fragments. Fusion powers the sun and hydrogen bombs, while fission is used in nuclear power plants and atomic bombs.
Both fission and fusion can be used to make nuclear bombs, in fact almost every nuclear bomb in stockpile in the world today uses both fission and fusion to achieve its total yield, optimize it material efficiency, and reduce size and weight.
It can.
The bombs used on Nagasaki and Hiroshima were both fission bombs, not fusion bombs.
It may be used in the fusion stage tamper of "clean" hydrogen bombs instead of depleted uranium, but other than that there is little use for it in any nuclear weapon.
Almost all modern nuclear explosive devices use some of each. The early atomic bombs used only fission. All hydrogen bombs use both fission and fusion. Some things you might want to look up are: boosted fission bomb, external electrical fusor neutron source, the plutonium "fission sparkplug" used in each stage of a hydrogen bomb, depleted uranium hydrogen bomb tamper can provide up to 90% of the total yield through fast fission.
Nuclear fusion is mainly used in the US for research purposes, with several projects working towards developing fusion as a viable energy source. Projects like ITER aim to demonstrate the feasibility of fusion power. However, commercial fusion power plants are not yet operational in the US.
Fusion and fission is related to combining (fusion) or splitting (fission) radioactive nuclei, in both cases releasing binding energy (The Strong Atomic Force). Fission is more commonly used in nuclear power plants and A-Bombs, while fusion is more commonly used in H-Bombs and in the Stars.