FOREIGN -RELATIONS, 1950, VOLUME I


II. Production of Fissionable Material by Particle Accelerators
  The possibility of producing fissionable material by means of high-
energy, high-current particle accelerators was of course not known
at the time the United Nations plan was formulated, but seems to be
covered by the general language and definitions of the plan., However,
there are a number of technical aspects of the plan which may need
to be made more explicit.
  Thorium may increase in importance. The First Report of the
United Nations Atomic Energy Commission stated that the danger
inherent in the diversion of thorium is less immediate than in the case
of uranium, because thorium cannot be used by itself for the produc-
tion of atomic energy. This may no longer be true, since the particle
accelerator may provide a means of utilizing thorium alone in the
production of U-233. The particle-accelerator development may have
the same general effect: as a reactor breeding program, in that it may
transform U-238 and thorium into fissionable material without being
limited by the U-2,35 content of natural uranium, thus greatly increas-
ing the potential supply of fissionable material. The Specific Pro-
posals of the Second Report made no distinction between the control
measures to be applied to thorium and uranium, although it was
realized that the control of thorium would be more difficult because
of the extent and mode of its occurrence and its use outside of the
atomic energy field.
   The particle accelerator may require a smaller inventory of source
 material for a given rate of production of fissionable material than
 a reactor, but may be comparable as regards size of installation, cool-
 ing and shielding requirements, and chemical processing plant. The
 requirements for electric power and specialized electrical equipment
 will be much. greater than for a reactor. It would therefore appear
 that the problems of detection and control would be no more difficult
 than for a reactor. It should be emphasized that the feasibility of a
 particle accelerator for production of fissionable material in quantity
 has not yet been demonstrated.
 III. Prospects for Atomic Power
   At the)-time the discussions of atomic energy began in the United
 Nations, there were some persons in this coun-tryland-elsewhere. who
 were sanguine of the early demonstration both of the practical genera'-
 tion of atomic power and of its economic ,feasibility. During the course
 of the discussions, it beame aplparent that numerous technioal.and
 economic problems were involved and that the time scale wasla matter
 of years'before a-tom-c power-could be demonstrated in a practical way
 and perhaps decades: beforeatomic power mighttbe utilized on*a large


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