ORNL-5388 - the Molten Salt Energy Technologies Web Site

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7.3.1. Possible Procedure for Implementing and
Commercializing the Denatured Fuel Cycle
On the basis of the above assumptions, and the discussion in Section 5.1, it is ob-
vious that the only reactors that could operate on denatured 233U fuel in the near term
(by 1991) would be LtlRs.
the introduction of commercial fuel reprocessing. One involves the use of "denatured 235U"
fuel (i.e., MEU(235)/Th) in LWRs, thereby initiating the production of 233U. However, this
scheme suffers from very high fissile inventory requirements associated with full thorium
loadings in LWRs (see Section 4.1). A second option involves the use of partial thorium
loadings in LWRs. In this option Tho2 is introduced in certain lattice locations and/or
MEU(235)/Th fuel is used in only a fraction of the fuel rods, the remaining fuel rods
being conventional LEU fuel rods. This scheme significantly reduces the fissile
inventory penalty associated with full thorium loadings in LWRs and for BWRs may offer
operational benefits as well (see Section 4.1). Also, the partial thorium loadings would
allow experience to be gained on the performance of thorium-based fuels while generating
significant quantities of 233U.
Two possibilities exist for producing 233U for LWRs prior to
Either of the above options for producing 233U will
probably require some form of government incentive since the Us08 and separative work
requirements (and associated costs) will increase with the amount of Th utilized in the
once-through throwawaylstowaway modes in LWRs.
Although a reprocessing capability would be required to recover the bred 33U from
thorium fuels, such a capability would not be required for the qualification and
demonstration of thorium-based fuel, which initially would employ 235U rather than 23%.
As has been pointed out above, the operation of LWRs with MEU(235)/Th or with partial
thorium loadings could be accomplished during the next decade while the development and
demonstration of the needed fuel cycle facilities for the implementation of the denatured
233U cycle are pursued.
secure fuel storage centers which would represent a growing stockpile of 23% and plutonium.
Additional fuel cycle service facilities, such as isotopic separation, reprocessing, fuel
refabrication and possibly waste isolation, could be introduced into these centers as the
need develops.
followed by larger prototypes and then comnercial-scale plants. It has been estimated
(in Section 5.2) that commercialization of a new reprocessing technology would require
12 to 20 yr and the commercialization of a new refabrication technology would require 8 to
15 yr.
Initially the spent fuel could be stored in repositories in
As pointed out above, these could initially be pilot-plant-scale facilities
With the deployment of the pilot-scale reprocessing and refabrication facilities,
recovery of Pu and U from spent fuel and the subsequent refabrication of Pu/Th and
denatured 233U/Th fuels could be demonstrated within the center. Pu/Th LWRs* could then
*That is, thermal transmuters of an LWR design (see Section 4.0). As used in this report,
a transmuter is a reactor (thermal or fast) which burns one fuel and produces another
(specifically, a reactor that burns Pu to produce 233U from Th).