Nuclear weapons: Difference between revisions

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* Fission chain reactions release moderately energetic "fission energy" neutrons. They affect materials differently:
* Fission chain reactions release moderately energetic "fission energy" neutrons. They affect materials differently:
** <sup>233</sup>U is fissile, and can be bred from <sup>232</sup>Th. Without subsequent physical enrichment, however, it'll be contaminated to some degree by:
** <sup>233</sup>U is fissile, and can be bred from <sup>232</sup>Th. Without subsequent physical enrichment, however, it'll be contaminated to some degree by:
*** <sup>232</sup>U ((<sup>233</sup>U,''n'') -> <sup>232</sup>U + ''2n'', (<sup>232</sup>Pa,β−) -> <sup>232</sup>U), a retarded younger brother notable for meager lifespan and γ-rich decay chain (though note that Georgia Tech researchers have fashioned <sup>232</sup>UBe<sub>13</sub> (<sup>232</sup>uranium beryllide) [http://smartech.gatech.edu/handle/1853/14650 neutron initiators], so it has that).
*** <sup>232</sup>U ((<sup>233</sup>U,''n'') -> <sup>232</sup>U + ''2n'', (<sup>232</sup>Pa,β−) -> <sup>232</sup>U), a retarded younger brother notable for meager lifespan and γ-rich decay chain  
*** Georgia Tech researchers have, however, recently fashioned <sup>232</sup>UBe<sub>13</sub> (<sup>232</sup>uranium beryllide) [http://smartech.gatech.edu/handle/1853/14650 neutron initiators]
** <sup>235</sup>U is fissile, but requires enrichment infrastructure (no plausible breeding path). It's a real dream to work with, and easier to ignite than a Sparkler. Modern cores employ <sup>239</sup>Pu due to (a) smaller critical masses (more energy per fission) (b) more intense neutron fluxes (more prompt neutrons per fission) and (c) metallurgists in search of big paychecks.
** <sup>235</sup>U is fissile, but requires enrichment infrastructure (no plausible breeding path). It's a real dream to work with, and easier to ignite than a Sparkler. Modern cores employ <sup>239</sup>Pu due to (a) smaller critical masses (more energy per fission) (b) more intense neutron fluxes (more prompt neutrons per fission) and (c) metallurgists in search of big paychecks.
** <sup>238</sup>U is not fissile, but can be bred into <sup>239</sup>Pu. Furthermore, it ''can'' be fissioned by the 14.7 MeV neutron resulting from D-T fusion, and there's an absolute ton of it.
** <sup>238</sup>U is not fissile, but can be bred into <sup>239</sup>Pu. Furthermore, it ''can'' be fissioned by the 14.7 MeV neutron resulting from D-T fusion, and there's an absolute ton of it.