Category: Criticality

Criticality, Los Alamos, Manhattan ProjectBy E.Fermi

Los Alamos or Tickling the Dragon’s Tail

Oppenheimer began recruiting for the laboratory with help from James Conant immediately after the site was chosen. There was reluctance of some in working to build powerful bombs and the belief by some that the project was a boondoggle that would have nothing to do with the war. Many declared they would not join the project if they had to be Army officers. Oppenheimer accepted the designation of lieutenant colonel and had ordered his uniforms, but Rabi warned him that others would resist joining him. Conant negotiated a compromise to begin the project under civilian administration and transition to the military later. The transition never happened, and recruits began to travel to Santa Fe to receive the clearances that allowed […]

Criticality, Nuclear ScientistBy E.Fermi

Fermi’s Pile

The Manhattan Project depended heavily on American industry through all of its activities, and the ability to build and operate Fermi’s reactor was no exception. Little or no uranium metal had been produced up to 1940. The open literature said that the melting point of the metal was “below 1850 degrees Centigrade.” Carbon was produced in the hundreds of tons, but its purity was unacceptable for a nuclear reactor. Westinghouse and the Metal Hydrides Company produced uranium pellets. Mallinckrodt Chemical provided a source that had reduced impurities. Harshaw Chemical and DuPont produced uranium tetrafluoride. The National Carbon Company and Speer Carbon Company were enlisted to produce the graphite that met high standards for purity. Fermi began to assemble the large […]