Uranium-235 is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238 it is fissile, i.e. it can sustain fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature.
Uranium-235 has a half-life of 700 million years and was discovered in 1935 by Arthur Jeffrey Dempster. Its nuclear cross section for slow thermal neutrons is about ...
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Uranium-235 is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238 it is fissile, i.e. it can sustain fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature.
Uranium-235 has a half-life of 700 million years and was discovered in 1935 by Arthur Jeffrey Dempster. Its nuclear cross section for slow thermal neutrons is about 1000 barns. For fast neutrons it is on the order of 1 barn. Most but not all neutron absorptions result in fission; a minority result in neutron capture forming uranium-236. The fission of one atom of U-235 generates 202.5 MeV = 3.244 × 10 J, i.e. 19.54 TJ/mol= 83.14 TJ/kg. Heavy water reactors, and some graphite moderated reactors can use unenriched uranium, but light water reactors must use low enriched uranium because of light water's neutron absorption. Uranium enrichment removes some of the uranium-238 and increases the proportion of...
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