The FuTure oF nuclear Fuel cycle - MIT Energy Initiative

Twice-Through Cycle
Table 7A.3 shows the key engineering and other
economic assumptions used to calculate the
LCOE for the Twice-Through Cycle. The calculations
of the levelized costs for the various components
are conducted in exactly the fashion as
described immediately above. However, since the
Twice-Through Cycle involves the expression of
the cost and credit for the separated plutonium,
we detail that calculation in particular, and we
show how the value for the separated plutonium
is derived. Also, because the cost of disposing of
the spent MOX is critical to the final LCOE, we
explain that calculation in some detail.
Reprocessing and Fuel Fabrication Costs as a
Function of the Value of Separated Plutonium
Each 1kg of spent UOX leads to the separation
of 0.011kg of plutonium. We denote the attributed
price of plutonium as p, denominated in
$/kgHM, and then calculate the total attributed
value to the separated plutonium, measured per
unit of electricity originally produced by the fuel
being reprocessed as:
table 7a.3 twice-through Fuel Cycle Specifications
FirSt reaCtor, burninG uox
Front-end fuel parameters
same as oTc
reactor capital costs
same as oTc
reactor operating costs
same as oTc
Spent fuel pool storage period
same as oTc
loss during reprocessing (u & Pu) 0.2%
reprocessed uranium recovered 0.930 kghM/kgihM
Plutonium recovered 0.011 kghM/kgihM
enrichment target for reprocessed u 5.16%
optimum Tails assay for reprocessed u 0.39%
Feed for reprocessed u 7.63 (initial kgu/enriched kgu)
Separative Work units for reprocessed u 4.80
Price of reprocessed u from uoX 108.30 $/kghM
SeCond reaCtor, burninG uox and mox
loss during MoX fabrication 0.2%
u-235 content of depleted uranium 0.25%
depleted uranium required as % weight 91.3%
Plutonium required as % weight 8.6%
lead time for plutonium separation 2 years
americium as % weight 0.1%
reactor capital costs
same as oTc
reactor operating costs
same as oTc
We leave this value expressed as a function of the as yet unspecified attributed price of plutonium,
p. This is solved for below.
By a similar calculation for the second reactor which is fed with MOX fuel fabricated from
the separated plutonium, and assuming that 8.73% of the fuel by weight is composed of
plutonium and Americium coming from spent UOX, we have:
The Second Reactor Back-end Fuel Cycle Cost
We assume that after a period of temporary storage the spent MOX will be sent to a geological
repository just as we had assumed for the spent UOX in the Once-Through Cycle.
We base our calculation of the cost of disposal of the spent MOX off of the cost of disposal
of spent UOX. This had included two parts: a cost of above-ground storage equal to
$200/kgiHM, and a cost of disposal in a geological repository equal to $470/kgiHM. The
$470/kgiHM cost for disposal is derived from the current 1 mill/kWh statutory charge to be
paid 5 years after unloading of the fuel. For spent MOX we assume the identical cost for the
appendix to chapter 7: economics 177