ABSTRACT
Otto Hahn succeeded in splitting the atom and proving the experimental evidence in 1938. After World War I, the 1920s and 1930s were a fascinating time of further development of the knowledge of the atom and quantum mechanics. The fast neutrons emitted from the split uranium-235 atoms are slowed down by a moderator; otherwise they are absorbed by the uranium-239, a process that is undesired in a commercial reactor, even though being not totally avoidable. Another advantage of working with slow neutrons is that the probability of capturing them for further splitting the U-235 and producing energy is higher than it is for the fast neutrons. In nuclear “breeder” reactors, one uses the effect of conversion of U-238 into plutonium by the fast neutrons. In the Manhattan Project, most effort went into the production of nuclear fuels. For the Manhattan Project, it was produced from U-238 in a water-cooled reactor at Hanford.
