The most efficient and rapid method for producing tritium is by inserting lithium metal into a large nuclear reactor, thus exposing it to irradiation by neutrons, which transmute the lithium into tritium and helium. Tritium could also be produced in a similar manner in the smaller nuclear reactors used for research purposes, and though these smaller reactors would produce it at a considerably slower rate, the fact that the amounts of tritium required may be rather small would inevitably shift these reactors from the “non-dangerous” to the “dangerous” category. Such small reactors are essential for research, and their prohibition would strike a vital blow at the progress of science. Furthermore, they could be much more easily hidden than large reactors. This fact, therefore, weakens, rather than strengthens the argument for the dismantling of all high-powered reactors, as such dismantling would not prevent the production of tritium. There are other, though less efficient, methods for producing tritium, however, that do not require any reactors at all. A good neutron source can be provided by exposing beryllium to radium, radon, or polonium. These neutrons could then be used to bombard lithium and convert it into tritium. Nor is lithium necessary, for at least four other elements, including deuterium, helium 3, boron, and nitrogen, can be transmuted by neutrons from the beryllium into tritium. What is more, even neutrons are not absolutely essential, since deuterons (nuclei of deuterium) and beryllium could be made to yield tritium by bombarding them with other deuterons. The latter method, however, would require the use of giant cyclotrons and would be very slow. All this would indicate that it would be extremely difficult, if not impossible, to provide safeguards against the clandestine production of tritium. 9. SHOULD A WORLD-WIDE GEOLOGICAL SURVEY COVER CONCENTRATED LITHIUM DEPOSITS? A key feature of the United Nations plan is the provision for a world-wide geological survey of uranium and thorium—the raw materials potentially usable in A-bombs. This survey is considered necessary in order to permit tracing of materials as they progress from the mines through various processing phases and finally enter a nuclear reactor. Does the same kind of logic apply to lithium—raw material for tritium? How formidable is the technical problem of locating and controlling deposits of lithium?