b'C H A P T E R 3T H E U RA N I U M T RA I L L EA DS T O I D A H OWith the discovery that a neutron could Developing any of these ideas would Early in 1939, scientists of the Unitedsplit uranium and generate more neu- require a great deal of uranium. One of States Naval Research Laboratory introns, a new demand for uranium was the inconvenient things about natural Washington, D.C., met with scientistsinevitable. Provided that enough urani- uranium is that 99.3 percent of it is ura- from Columbia University and Enricoum-235 is packaged in just the right nium-238, an isotope that resists split- Fermi, Nobel laureate nuclear physicist.way, the liberated neutrons are likely to ting apart under neutron bombardment. They discussed how the heat of fissionhit one or two other atoms and cause For every 140 atoms of U-238, there is might produce steam for a turbine andthem to fission also. This was the phe- only one atom of U-235. 3 propel a ship or submarine. Navy scien-nomenon of the chain reaction. Fissionreleased an amount of energy far largerthan the energy obtained from chemicalreactions of the same mass. Scientistslearned that it is possible to create anenvironment in which to start such areaction, whereupon natureandskilled operatorskeep the reactiongoing.In the late 1930s, events in Europewere pointing to a German war of con-quest. It required no great leap of imag-ination to realize that a chain reactioninitiated in a well-engineered containercould explode as a bomb. If chain reac-tions could be controlled, on the otherhand, they could produce electricity orhelp build canals and harbors.Above. In the 1950s, the AEC published films andbooklets to help American citizens understandnuclear energy. Left. The USS Bang, a pre-nuclearU.S. Navy submarine built in 1943, used diesel fuelto generate electricity. When submerged, it ran onbattery power and had to surface every 48 hours.Courtesy of Department of the Navy, Submarine Force Museum2 1'