Carroll Quigley - Tragedy and Hope - A History of the World in Our Time

To separate U-235 from U-238 by physical methods, four techniques were attempted on parallel paths. Two of these ceased to be significant after the end of 1943. The two survivors were gas diffusion and electromagnetic separation. In the latter, gaseous compounds of uranium were electrically charged so that they would move along a vacuum tube and pass through a powerful magnet which made them swerve. The heavier U-238 compounds would swerve less than the slightly lighter U-235 compounds, and the two could be separated. Using the gigantic new cyclotron magnet at the University of California, which was 184 inches across, Ernest O. Lawrence and Emilio Segre showed that it would require about 45,000 such units to separate a pound of U-235 a day.

The electromagnetic separator plant (called Y-12) as set up at Oak Ridge in 1943 covered 825 acres and was housed in 8 large buildings (two of which were 543 feet by 312 feet). Several thousand magnets, most of which were 20 feet by 20 feet by 2 feet, consumed astronomical quantities of electricity in separating uranium isotopes into gigantic tanks. These tanks, weighing fourteen tons each, were pulled out of line by as much as three inches by the magnetic attractions created, straining the pipes carrying uranium compound, and eventually they had to be fastened to the floor. Since copper for electrical connections was in such short supply, 14,000 tons of silver from the Treasury reserve of American paper money was secretly taken from the Treasury vaults (although still carried publicly on the Treasury balance sheets) and made into wiring for the Y-12 plant. From this plant came much of the U-235 used in the Hiroshima A-bomb.

The gaseous-diffusion method, which had been carried fairly far by the British before America took it over, took advantage of the fact that atoms of lighter U-235 gas move more rapidly than the heavier U-238 and thus pass more rapidly through a porous barrier. If a mixture of the two isotopes, in the only available gaseous form of the unstable and violently corrosive uranium hexafluoride, were pumped thus through 4,000 successive barriers, with billions of holes, each not over 4 ten-millionths of an inch, the mixture after the last barrier would be largely the U-235 form of the compound (90 percent pure).

By the end of April 1943, in three adjacent valleys near Oak Ridge, Tennessee, three plants were under construction for gaseous diffusion and electromagnetic separation of U-235 and for a large uranium pile to make plutonium out of U-238. By the end of the war, Oak Ridge, covering 70 square miles, had a population of 78,000 persons and was the fifth largest community in Tennessee. Because the plutonium plant was so dangerous, owing to its enormous generation of heat and radioactivity, a larger and more isolated plant was begun on a tract of 670 square miles near Hanford, Washington. A construction camp of 60,000 workers was set up there in April 1943; construction of the first fission pile was begun in June; and it began to operate in January 1945. It is interesting to note that the two sites at Oak Ridge and Hanford were chosen for their proximity to the hydroelectric power plants of the Tennessee Valley Authority and Grand Coulee which had been built by Roosevelt’s New Deal. By the end of the war, nuclear production was using a large fraction of the total electricity produced in the United States, and would have been impossible without these great electrical-generating constructions of the New Deal (which were still regarded with intense hatred by American conservatives).

A third site, for research on the bomb itself and its final assembly, was built on a flat mesa near Los Alamos, New Mexico, twenty miles from Santa Fe. Robert Oppenheimer of the University of California, with the world’s greatest assemblage of working scientists (including almost a dozen Nobel laureates), planned and constructed the earliest bombs at that isolated spot.

Until May 1, 1943, these complex projects were operated by committees and subcommittees of scientists of which the chief chairmen were James B. Conant, Vannevar Bush, E. O. Lawrence, Harold Urey, and A. O. Compton. The actual construction work was delegated to the United States Army Corps of Engineers in charge of Leslie R. Groves, an expert on constructing buildings, whose chief achievement was the Pentagon Building in Washington. From his graduation at West Point, Groves had held only desk jobs, had been a lieutenant for seventeen years, and was still a major when war began. He was raised to brigadier general on his appointment as head of the Manhattan District, in charge of the physical administration of the atom-bomb project in September 1942. On May 1, 1943, he took over total charge of the whole project.

An earnest, hard-working man, Groves had little imagination, no sense of humor, and not much familiarity with science or scientists (whom he regarded as irresponsible “longhairs”). Although he drove himself and his associates relentlessly, he greatly hampered the progress of the task by his fanatical obsession with secrecy. This obsession was based on his belief that the project involved fundamental scientific secrets (there were no such secrets). His efforts were quite in vain, as the only real secrets, the technological ones regarding isotope separation, critical mass, and trigger mechanisms of the bombs, were revealed to the Soviet Union, almost as soon as they were achieved, by British scientists. The secrecy, thus, was secrecy for the American public rather than for the Germans or the Russians (neither of whom were actually seeking the information, since, like General Groves himself, they had little faith in the feasibility of the project).

For security reasons General Groves “compartmentalized” the work, and allowed only about a dozen persons to see the project as a whole. Consequently, the vast majority of those working on the project were not allowed to know what they were really doing or why, and this lack of perspective greatly delayed the solution of problems. The whole project of about 150,000 persons were segregated from their fellow citizens; all communications were cut off or censored; and the project was overrun with guards and security officials who did not hesitate to eavesdrop, read mail, monitor telephones, record conversations, and isolate individuals. These activities significantly delayed American achievement of the atom bomb without achieving their ostensible purpose, since there is no evidence either that the three enemy Powers could have made the bomb or that Russia’s making of the bomb was significantly delayed by General Groves’s extreme degree of secrecy.

General Groves’s personal position was paradoxical. He took the assignment with disappointment and reluctance, had no real faith that the project would be successful until it actually was, carried secrecy to the nth degree, yet was convinced that the engineering problems were so colossal that the Soviet Union, even if it had the knowledge of how we did it, would be unable to repeat the achievement in less than twenty years, if ever. I myself heard General Groves make these statements in 1945. On the other hand, General Groves was a tireless and driving manager and an expert manipulator of the personal, political, and military arrangements which made the bomb possible.

In the last two years of the project (July 1943-July 1945), it passed through crisis after crisis in a frenzied sequence which made it appear, every alternative month, that it would be a $2 billion fiasco. In January 1944, when the enormous gaseous-diffusion plant at Oak Ridge was under full construction but without the diffusion barriers, since no effective ones could be made, it became necessary to junk the barriers on which tests had been made for almost two years and to turn to mass production of millions of square feet of a new barrier which had scarcely been tested. When this plant began to operate, section by section, at the end of the year, it worked so ineffectively that it seemed almost impossible that the concentration of U-235 could ever be raised over 15 or 20 percent without the construction of miles of additional barrier which would delay the bomb by months and use up fantastic quantities of uranium hexafluoride gas just to fill the chambers. Similarly, the electromagnetic separator plants suffered breakdown after breakdown, and operated at a level which made it seem impossible to raise the U-235 content over 50 percent.