The Plutonium Project

Abstract

The Plutonium Project was that part of the organization for the production of atomic bombs charged with the scientific task of finding out how to make and isolate plutonium and with the industrial task of producing purified plutonium in sufficient quantities to be useful. It was organized and operated in the beginning under the Office of Scientific Research and Development. It went forward to a successful conclusion with the Manhattan District of the U. S. Engineers acting as the co-ordinating, expediting, and financing agency. The scientific work was performed under a contract with the University of Chicago and the industrial development with the E. I. du Pont de Nemours Company. Scientists, industrial engineers, and others of many skills were brought to Chicago to work in the Metallurgical Laboratory of the University of Chicago, as it was called during the war. One might well ask why the biological work on which a symposium presented at the meeting of the Radiological Society of North America and the papers in this issue of Radiology are based was done in connection with such a project. The answer is obvious to all who know even superficially how plutonium was produced. Uranium fission, chain-reacting piles, fission products, and artificial radioactive materials are now household words. They were all a part of the “Plutonium Project.” To make plutonium, it was necessary to utilize the great numbers of neutrons produced during the fission of U235 to transmute U238 into neptunium. This element then changed to plutonium by radioactive decay. The process produced recoil nuclei, alpha rays, beta rays, fast neutrons, slow neutrons, and gamma rays in intensities never before dreamed probable or possible. Moreover, the plutonium when formed was embedded in uranium along with fission products whose radioactivity was equivalent to thousands of grams of radium. The workers in the laboratories and plants had to be protected and the health of the public in surrounding territories had to be safeguarded. The problem of the maximum permissible exposure (tolerance dose) that would produce no immediate or late changes was no longer of interest only to a limited group of radiologists and radium workers, but became one of significance to thousands of people. The scientific data on which it was based were found to be very sketchy. What are the first changes produced by exposures just above the tolerance level? Is the peripheral blood picture as reliable an indicator of over-exposure as radiologists have considered it to be? Are there any other changes produced that can be detected by known or newly developed clinical tests? Can a person ever recover completely and entirely from any dose of radiation big enough to produce detectable effects? Are there any methods of treatment that will aid in recovery? How much radiation is necessary to kill a man?