Trinity: The Weapons Scientists and the Nuclear Age

TRINITY: THE WEAPONS SCIENTISTS. AND THE NUCLEAR AGE JohnJ. Weltman Batter my heart, three-person'd God, for you As yet but knock, breathe, shine, and seek to mend. That I may rise and stand, o'erthrow me, and bend Yourforce, to break, blow, burn, and make me new. —John Donne Holy Sonnets M.any know that Robert Oppenheimer chose the name Trinity as the code word for the first test of a nuclear explosive device. Few know why. Oppenheimer tells us that the passage cited above was in his mind when he chose the name. In that passage, we see a hope that the products of science could transform the world, making it a better place. This faith operated at the beginning of the enterprise at Los Alamos National Laboratory. It still energizes and justifies the work being done by the weapons scientists today. This is not to say that the scientists were motivated then or now by the hoped for consequences of their activities. The sheer intellectual fascination of the problems on which they work provides the principal motive for the labors of many scientists today, as it did in 1943. When good physics seems to offer the prospect of making a radical transformation in human affairs, however, the morale of the scientific community is at its height. The period from 1943 to 1945 was such a time for many in the scientific community. Now is another such time, offering John J. Weltman is a member of the Strategic Analysis Group at Los Alamos National Laboratory. He has published widely in such areas as nuclear weapons proliferation, strategic studies, and international relations theory. The opinions expressed in this article are his own and not intended to represent those of his employer, Los Alamos National Laboratory, which is operated by the University of California for the U.S. Department of Energy. 29 30 SAIS REVIEW the hope that the development of fascinating new technologies may radically improve the strategic environment in which we live. Good physics and hopes for transformation, however, have not determined the course ofweapons development. Scientists have operated within an environment dominated by policymakers and strategists. Although scientists have often been able to present policymakers with new opportunities or to demonstrate to them the limits of the possible, the final decision that governs the shape and emphasis of the work of the weapons science community has been made by those holding the reins of policy. When Los Alamos was founded in 1943, there existed a broad theoretical consensus that nuclear fission could produce an explosive, and that such an explosive could be much more powerful than existing explosives. There also existed a broad consensus on the most promising of techniques to create such an explosion. It was widely believed, furthermore, that a fission weapon could decide the course of the war. But this general theoretical consensus obscured a host of complex problems facing the scientists when they attempted to actually design the device. How much fissionable material would be required to produce an explosive chain reaction? How fast would that material have to be brought together? How would that material behave under conditions of extreme stress and pressure? All these questions required precise rather than general answers. Yet the data upon which answers to these questions could be based in most cases did not exist. Only miniscule quantities of fissionable materials were available, as mass-quantity production of the materials had not begun. Controversy raged about which techniques would be most efficient in that production, and it was necessary to extrapolate from tiny samples the basic facts about the physical characteristics of the fissionable materials. Design of the weapons could not await the arrival of sufficient quantities of materials and precise conclusions. The fear that the United States was in a race with the Germans to produce the weapon and the potentially disastrous consequences for the country that came in second in that race dictated that weapon design and the investigation of the physical characteristics of the fissionable material proceed simultaneously . The lack of basic knowledge about plutonium's characteristics produced a crisis and a sudden shift in the direction of the design. Theoretically, a supercritical...