Nuclear Power - A Short History
Nuclear fission is the splitting of the nuclei of (normally) very heavy or unstable elements (normally heavier than iron), resulting in a release of large amounts of energy as well as the unstable, radioactive isotopes of lighter elements, as well as any logical number of neutrons. For uranium 235, the most abundant usable fuel present in nature, the number of neutrons released is about 2.4 per atom, and the energy released is about 215 MeV per atom (Example, nd), or about
215 MeV * 6.02*10^23 235U * 1000 g * joule
235U 1 * g * Kg * MeV * 1.602*10-13
= 8.05*10^15 joule or 8.05 petajoule per kilogram of uranium 235
However, uranium is not found in natural concentrations of more than 0.7% of any given amount of uranium; in order to efficiently obtain energy from uranium, one must "enrich" the uranium, or concentrate the usable isotopes (Uranium, nd).
Leo Szilard, a Hungarian scientist who had recently escaped Berlin for London, first entertained the idea of a chain-reaction of radioactive isotopes in 1933 (Szilárd, 2006); he patented his idea in 1936 in the U.K., and shared a patent with Enrico Fermi in the United States. Later, Otto Hahn and Fritz Stressmann, along with Lise Mietner and her nephew Otto Frisch, discovered fission when Hahn and Stressmann bombarded uranium with neutrons, resulting in the emission of a few smaller atoms in addition to neutrons and energy; Mietner and Frisch interpreted the resulting energy and atoms as being the results of fission of the uranium atoms' nuclei ("History," Georgia State University, nd); this fission resulted in huge amounts of energy per reaction (on the order of 200 mega electron-volts per atom of uranium 235). In 1942 and after deciding that uranium would be the best candidate for sustained fission (they had heard
Nuclear Energy 3
about Hahn and Fritz's experiment in 1939), Szilard and Fermi decided to construct a "neutronic reactor." Before proceeding, Szilard obtained Albert Einstein's endorsement in writing a letter to Franklin Delano Roosevelt explaining the potential for nuclear fission in bombs Leó Szilárd, 2006); he then moved to Chicago to continue work with Fermi and to construct the reactor Chicago Pile 1, the world's first nuclear reactor (Chicago, 2006). See also (Nuclear Fission, 2006).
Thereafter, attention shifted towards the development of nuclear weapons (Szilárd, 2006). Much was learned about nuclear fuel based on experiments conducted during the war, including the differences in half-life between 240Pu and 239Pu— the former being much shorter, thus complicating explosive reactions.
After the war, military research continued, but some research was devoted to civilian-reactor development, eventually culminating in the EBR-1 (experimental breeder reactor 1) in Idaho Falls: in December of 1951, four light bulbs were lit by the electricity generated by the reactor (Stefan, 2001; About, 2006). However, the first American nuclear power plants...