Actually, most nuclear weapons get roughly comparable amounts of their force from fission and fusion, usually a little more from fission. Fission-only bombs are so much less powerful not because fission is but because they have very incomplete fission (around 1% for the Hiroshima bomb design, for example). The fusion reactions used in bombs produce a lot of excess neutrons, by design; all those neutrons flying around mean a lot more fission ends up happening. The only bombs that get most of their power from fusion are neutron bombs (which use a lot less fissionable material, and use the excess neutrons to increase the radiation damage) and clean bombs (which also use a lot less fissionable material, but replace it with lead to absorb the excess neutrons; clean is of course a relative term here).
The biggest difference as regards fission is that fusion bombs use U-238 as a power source, which is capable of releasing energy from fission, but which doesn’t produce enough neutrons to sustain a chain reaction. But when fed excess neutrons from a fusion reaction, you get an immense energy release from a very cheap material that’s used as the bomb casing.
Actually, the process in stars is fusion. The same as modern atom bombs, too.
Fission is used in nuclear power plants, and only really used to reach the conditions for fusion in bombs.
Actually, most nuclear weapons get roughly comparable amounts of their force from fission and fusion, usually a little more from fission. Fission-only bombs are so much less powerful not because fission is but because they have very incomplete fission (around 1% for the Hiroshima bomb design, for example). The fusion reactions used in bombs produce a lot of excess neutrons, by design; all those neutrons flying around mean a lot more fission ends up happening. The only bombs that get most of their power from fusion are neutron bombs (which use a lot less fissionable material, and use the excess neutrons to increase the radiation damage) and clean bombs (which also use a lot less fissionable material, but replace it with lead to absorb the excess neutrons; clean is of course a relative term here).
The biggest difference as regards fission is that fusion bombs use U-238 as a power source, which is capable of releasing energy from fission, but which doesn’t produce enough neutrons to sustain a chain reaction. But when fed excess neutrons from a fusion reaction, you get an immense energy release from a very cheap material that’s used as the bomb casing.
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