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232"
Fig. 3.0-1. Decay of 232U.
ORNL-DWG 65-55DR3
3-4
The radioactivity associated with the
233U significantly impacts the associated fuel
cycle. The fabrication, shipping, and handling
of the fresh denatured fuel is expected to
differ markedly from the other cycles , primari ly
due to the fact that remote procedures will
have to be employed throughout. To design the
necessary facilities will require a knowledge
of the concentrations of 232U (and its daughter
products) in the fuel as a function of time.
To date, insufficient data are available on
this subject, but on the basis of some pre-
liminary investigations some estimates are
given in Section 3.1 on the 232U concentrations
that could be expected in the recycled fuel of
LWRs , HTGRs , and FBRs operating on denatured
233u.
The radiological hazards associated wfth
the use of denatured 233U fuel represent another
aspect of the cycle demanding attention.
Again
little information is available, but Section 3.2
discusses the toxicity of the various isotopes
present in the fuel and also in thorium ore,
as well as the effects of exposure to the gamma
rays emitted from the fresh fuel.
In assessing the safeguard features of denatured 233U fuel, the isotopics of the cycle
must be examined from several viewpoints.
an inherent property of the 4denatured fuel cycle, the concentration of the isotopic denaturant,
238U, is controllable.
the denatured fuel cycle.
venting the intrinsic isotopic barrier is increased.
also increases the 239Pu concentration in the spent fuel so that an obvious trade-off of
proliferation concerns exists between the front and back ends of the denatured fuel cycle.
As pointed out in Section 3.3.1, the enrichment criteria for denatured 233U fuel are still
being formulated.
While the 232U contamination will be essentially
The presente of both isotopes affects the proliferation potential of
As the 238U concentration is increased, the difficulty of circum-
However, increasing the 238U fraction
The requirement for remote operations throughout the fuel cycle will in itself
constitute a safeguard feature in that access to fissile material will be difficult at all
stages of the cycle.
of the fuel recycling steps and operations.
But this requirement will also be a complicating factor in the design
This subject is treated in more detail in
Chapter 5, but Section 3.3.2 of this chapter points out that the remote operation requirement
could dictate the selection of techniques, as, for example, for the fuel fabrication process.