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?
Pegmatite minerals constitute a principal source of lithium ores, which
are currently produced as a byproduct of the nonmetallic mineral
industry. Commercial deposits of lithium are known to exist in the Black
Hills of North Dakota; northern New Mexico; Saskatchewan, Canada; and
southwest Africa. Production of ores rose to about 900 tons of lithium
oxide in 1944 and is now about 200 tons. So long as requirements do not
exceed byproduct production, supply does not appear to present a
problem. If requirements exceed byproduct supply, the cost of the excess
might be high. Lithium is now used commercially in glass, as a compound
in welding fluxes, in storage batteries, in fluorescent light tubes, and
as an alloying element.
Are the quantities of lithium ore required on an order of magnitude that
makes control feasible?