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

Theory reached this far by the spring of 1940. At that time, in the space of the months April to June, several things happened: (1) the Nazis overran Denmark and Norway, capturing Bohr in one country and the world’s only heavy-water factory in the other country; (2) news reached America that the Nazis had forbidden all further sales of Czechoslovakia’s uranium ores and had taken over the greater part of Germany’s major physical research laboratory, the Kaiser Wilhelm Institute in Berlin, for uranium research; (3) a blanket of secrecy was dropped throughout the world on scientific research on nuclear fission; and (4) the Nazis overran the Netherlands, Belgium, and France, capturing, among others, Joliot-Curie. At that time uranium was a largely worthless commodity of which a few tons a year was used for coloring ceramics; it was produced only incidentally as a byproduct of efforts to produce other minerals such as cobalt or radium. Just before war began, Edgar Sengier, managing director of Union Minière of Katanga, Belgian Congo, learned from Joliot-Curie his discovery of chain fission of Uranium-235. Accordingly, after the fall of France, Sengier ordered all available uranium ore, 1,250 tons of it, shipped to New York. This ore was 65 percent uranium oxide, compared to marketable North American ores of 0.2 percent, and the full-scale postwar exploitation of South African ores of .03 percent! For more than two years Sengier could find no one in the United States interested in his ores, which lay in a warehouse on Staten Island until the end of 1942.

Just before the curtain of secrecy on atomic research fell in the spring of 1940, astounding information on the subject was published in Soviet Russia, but, like most Russian-language publications, was ignored in the outer world. In 1939 the Soviet Academy of Sciences set up, under the chairmanship of V. I. Vernadsky, director and founder (1922) of the Leningrad Radium Institute, an “Isotopes Committee” to work on the separation of uranium isotopes and the production of heavy water. The first cyclotron in Europe, an atom smasher of four million electron volts (4 MeV) which had been operational since 1937, went into full experimental use in April 1940, and, at the same time, the Academy of Sciences ordered immediate construction of a cyclotron of 11 MeV, comparable to the world’s largest, the 60-inch cyclotron at the University of California, operated by Ernest O. Lawrence, the inventor of these machines (Nobel Prize, 1939).

In this same fatal spring of 1940, a conference on isotope separation in Moscow publicly discussed the problem of separation of U-235; subsequently, Y. B. Khariton and Y. B. Zeldovich published a paper on the problem of the critical mass for spontaneous explosion of this isotope (“The Kinetics of Chain Decomposition of Uranium,” in Zhurnal Eks-perimentalnoi i teoreticheskoi, X, 1940, 477). This was followed by publication of similar papers, some even in 1941, which might have shown clearly to anyone who wished to see that the Soviet Union ‘was further developed than the United States at that time. No one, unfortunately, did wish to see. About the same time, Edwin A. McMillan (Nobel Prize, 1951) and Philip H. Abelson, using E. O. Lawrence’s great cyclotron at Berkeley, California, had studied the results arising from neutron bombardment of Uranium-238, and indicated the nature of 93 neptunium and the fissionable possibilities of 94 plutonium ( Physical Review , June 15, 1940). Bohr, as well as Louis A. Turner of Princeton, had already indicated some of the characteristics, including fissionability, of plutonium.

The Soviet position in atomic research in 1940 is astonishing in view of the depredations inflicted on Soviet scientists by Stalin in the purges of 1937-1939. In June 1940, Soviet science in this subject was about on a level with that of the German scientists who remained in Nazi Germany, although both were far behind the refugee scientists who were still making their ways westward to the English-speaking world. The Soviet scientists were, apparently, interested in atomic research only for industrial power purposes, and were not much concerned with achieving atomic explosives. Accordingly, they concentrated on atomic piles of mixed uranium isotopes, rather than on uranium separation, and most of their work was suspended after the Nazi invasion in 1941. In a similar way the remaining German scientists, although seeking the bomb, decided in February 1942 that large-scale separation of isotopes was too expensive to be practical, and spent the rest of the war years on the hopeless task of trying to devise an atomic pile which could be used as a bomb. The great German error was their failure to reach the conception of “critical mass,” the point which had been published in Russia in 1940.

In the United States and Britain the impact of the events of 1940 was much more intense among the refugee scientists than among the Americans. On the whole, the refugees had a higher level both of scientific training and of political awareness than the native scientists, and most of the outstanding American scientists had acquired their specialized knowledge in Europe, chiefly at Göttingen or elsewhere in Germany. As early as April 1939, a group of Hungarian refugees, led by Leo Szilard and including Eugen Wigner, Edward Teller, and John von Neumann, tried to establish a voluntary censorship of research information and to arouse the American government to the significance of the possible atom bomb. On March 17, 1939, Fermi visited the admiral in charge of the Technical Division of Navy Operations but could arouse no interest. In July Szilard, driven once by Wigner and a second time by Teller, made two visits to Einstein and persuaded him to send a letter and memorandum to President Roosevelt through the banker Alexander Sachs. The President read the material on October 11, 1939, and the wheels of government began to move, but very slowly. Only on December 6, 1941, the day before Pearl Harbor, was the decision taken to make an all-out effort to unlock atomic energy.

When the curtain of secrecy fell in June 1940, all the theory needed for the task was known by all capable physicists; what was not known was (1) that their theories would work, and (2) how the immense resources needed for the task could be mobilized. As late as 1939, less than an ounce of uranium metal had ever been made in the United States. Now it was necessary to make tons of it in extremely refined form. To build an atomic pile for a controlled nuclear reaction, hundreds of tons of heavy water or of graphite refined to a degree hitherto unknown were also needed. This task, entrusted to the direction of Arthur H. Compton (Nobel Prize, 1927), with Fermi doing the actual work, was set up at the University of Chicago. The pile of purified graphite with lumps of uranium all through it was built in a squash court under the West Stands of Stagg Field, where football had been discontinued. The pile of graphite, shaped as a roughly flattened sphere about 24 feet in diameter, had 12,400 pounds of uranium in small scattered lumps distributed in a cube at its center. Neutron counters, thermometers, and other instruments kept track of the fission rate going on inside it. Before the top layers could be added, these indicators began to rise increasingly rapidly to danger levels; therefore rods of cadmium steel were inserted through the graphite lattice. Cadmium, which absorbs large quantities of neutrons without being changed, could be used to hold back the fission process until the pile was finished. On December 2, 1942, before a team of scientists, these cadmium rods were slowly withdrawn to the point where a chain nuclear reaction took off. It could be damped down or speeded up to explosive level simply by pushing the rods in or pulling them out. This first sustained nuclear reactor was a great success, but it contributed little toward an atom bomb. Within it, at full operation, plutonium was made at a rate which would require 70,000 years to obtain enough for a bomb. This pile operated on purified natural uranium in which the U-238 was 140 times the U-235.