ORNL-5388 - the Molten Salt Energy Technologies Web Site

7-9
Viewed solely from the plutonium production viewpoint, the order of preference in terms
of higher proliferation resistance for the various denatured reactor candidates to be employed
at dispersed sites is as follows: HTR-PBR, HWR, HTGR, LWR, and SSCR. However, other factors
must also be addressed in evaluating the candidate reactors, one of which is that their
plutonium production maintains the symbiosis of a system that includes plutonium-fueled 233U
producers in secure energy centers. This plutonium being consumed within the center as it is
recovered from the spent fuel would limit the amount of plutonium available for possible
diversion. While such an energy center could also be implemented for the Pu/U cycle, the
denatured cycle would permit the dispersal of a larger fraction of the recycle-based power
generation capability. Hence, the number and/or size of the required energy centers might
be markedly reduced relative to the number required by the Pu/U cycle.
7.1.4. Conclusions
The proliferation-resistant characteristics of the denatured 233U fuel cycle derive from
its intrinsic isotopic barrier, its gamma radiation barrier, and its relatively low content of
chemically separable fissile material in spent fuel:
The isotopic denaturing of the denatured 233U cycle would provide a significant
technical barrier (although not an absolute one) that would decrease with time
at a rate which is country-specific. Technologically primitive countries will
find it an imposing barrier relative to other routes. Countries that have the
technological expertise to develop isotope separation capabilities will have the
technology required to circumvent this barrier; however, they will also have the
option of utilizing possible indigeneous natural uranium or low enriched 235U fuel
as alternate feed materials.
The denatured 233U cycle imposes a significant radiation barrier due to the 232U
daughter products in the fresh fuel as an inherent property of the cycle. Such
a radiation field increases the effort required to obtain weapons-usable material
from fresh denatured reactor fuel.
While the amount of plutonium discharged in the denatured 233U fuel cycle is
significantly less than in either the Pu/U cycle or the LEU cycle, the presence
of plutonium in the cycle (even though it is in the spent fuel) does represent
a proliferation concern. Conversely, it also represents a resource potentially
useful in a symbiotic power system employing denatured fuel. The concept of a
safeguarded energy center provides a means of addressing this duality in that
the fissile plutonium can be burned in the center to produce a proliferation-
resistant fuel.
In summary, the denatured 233U fuel cycle offers a technical contribution to proliferation
resistance. However, the fuel cycle must be supplemented with political and
institutional arrangements also designed to discourage proliferation.