PLENTIFUL ENERGY

14.9 How to Deploy Pyroprocessing Plants?
In discussing the IFR and pyroprocessing in earlier chapters, we have assumed
that the fuel cycle facility will be co-located with the reactor plant, as was done for
the EBR-II and its fuel cycle facility. This is the logical choice for the initial IFRs
deployed. Because of the criticality constraint, pyroprocessing and refabrication
equipment systems are sized naturally to serve a single reactor or two. The colocated
fuel cycle facility also eliminates the transportation of spent and new fuels.
It is the obvious choice. But as more IFR plants are built, there may be an
advantage in a regional fuel cycle center that will serve several IFR plants,
especially within the same utility grid and in geographical proximity. Some
economies of scale can be achieved and further improvements made in terms of
operational flexibility and capacity expansion, at the expense of possible objections
to transport.
In pyroprocessing LWR spent fuel, the obvious question is whether the
processing of LWR spent fuel can be or should be done in the same facility as for
the IFR. The LWR spent fuel contains on the order of 1% fissile actinides vs. ~20%
in the IFR. The criticality constraint that limits the equipment size in IFR
processing can be relaxed for LWR spent fuel processing. To a first order of
approximation, the LWR spent processing batch size can be increased by some
factor approaching twenty or so, given by the difference in fissile fractions, and will
need some such increase to be economically viable. LWR processing also requires
the new front-end step for oxide to metal conversion described in Chapter 10. Some
process steps could share equipment systems, product consolidation, and waste
processing, for example; however, even those processes would require multiple
equipment systems. All in all, the requirements and the optimization possible are
quite different, and it seems best to take the equipment systems for LWR spent fuel
processing and IFR fuel processing as two independent systems. Combining the two
complicates materials accountability as well, and seems unlikely to show any
significant countering advantage. If economies of scale are possible, the IFR fuel
cycle facility should be designed for multiple IFRs, and LWR spent fuel processing
plants should be free to handle as much throughput as necessary.
The related question is whether LWR spent fuel processing should then be
centrally located or regionally dispersed. Currently, LWR spent fuel in the U.S. is
accumulated at about two thousand tons a year. The LWR reprocessing capacity
needs to be in the range of three thousand tons/year to handle the annual discharge
as well as a start on reduction of the existing inventory. Currently operating
aqueous reprocessing plants typically have an eight hundred tons/year throughput
capacity. But a large central plant with two to three thousand tons/year is also
possible, and would have some economies of scale advantages. The Barnwell
reprocessing plant being built in the ‗70s was designed for fifteen hundred
tons/year.
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