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In fusion-based nuclear weapons, a fission bomb is used to create the temperature and pressure needed to kick off nuclear fusion. Calling that "combined fusion/

by wtracy 14y ago

In fusion-based nuclear weapons, a fission bomb is used to create the temperature and pressure needed to kick off nuclear fusion. Calling that "combined fusion/fission" is like calling my car an electric hybrid because it uses an electric starter. Detonating a nuclear weapon inside of a power plant isn't really practical. :-) Existing nuclear power plants don't get anywhere near the temperature and pressure needed to start nuclear fusion. So, now we have the engineers trying all sorts of ways to get to the needed temperature and pressure without turning the plant into a smoking crater. That's where all the fancy lasers and magnetic pulses described in the article come in: They're trying to aim the heat source so they can superheat the fuel without melting the containment vessel.

jsn 14y ago
That's a popular misconception, IIRC. Actually, in thermonuclear weapon the bulk of energy comes from fission. [1] Fusion is technically only used to get the high energy neutrons to get the bulk of fissionable material to undergo fission. So, ironically, calling it a "fusion bomb" is very much like calling your car an electric hybrid. 1. http://en.wikipedia.org/wiki/Thermonuclear_weapon http://en.wikipedia.org/wiki/Thermonuclear_weapon
- Udo 14y ago
  Where those weapons get the most energy from depends heavily on the design. It's true that multi-stage thermonuclear devices often have a final fission stage where huge amounts of energy are released, however if one were to purposefully maximize energy release while minimizing fallout there are some relatively clean fusion/fission ratios achievable. For instance, the test version of the Tsar bomb had its last fission stage removed, reportedly resulting in a 97% fusion detonation. Of course, those still cause a huge lethal neutron flux, but at least the amount of fission material released is pretty small in relation to the overall power of the device.

by wtracy 14y ago

jsn 14y ago

That's a popular misconception, IIRC. Actually, in thermonuclear weapon the bulk of energy comes from fission. [1] Fusion is technically only used to get the high energy neutrons to get the bulk of fissionable material to undergo fission. So, ironically, calling it a "fusion bomb" is very much like calling your car an electric hybrid. 1. http://en.wikipedia.org/wiki/Thermonuclear_weapon http://en.wikipedia.org/wiki/Thermonuclear_weapon

Udo 14y ago
Where those weapons get the most energy from depends heavily on the design. It's true that multi-stage thermonuclear devices often have a final fission stage where huge amounts of energy are released, however if one were to purposefully maximize energy release while minimizing fallout there are some relatively clean fusion/fission ratios achievable. For instance, the test version of the Tsar bomb had its last fission stage removed, reportedly resulting in a 97% fusion detonation. Of course, those still cause a huge lethal neutron flux, but at least the amount of fission material released is pretty small in relation to the overall power of the device.