The FuTure oF nuclear Fuel cycle - MIT Energy Initiative

Fast reactor technical Characteristics (continued)
The spent Fr fuel reprocessing and
the Fr fuel fabrication (including shipping
and storage at reactor site) are
assumed to take 1 year 2 each.
notes
1. We deem 5 years to be more realistic.
[Bunn et al., 2003] implicitly assumes only
1 year of cooling before reprocessing;
[NEA, 2009] assumes 4 years of cooling
before reprocessing; [NEA, 2002] assumes
2 years of cooling, including reprocessing;
[de Roo and Parsons, 2009] assumes
5 years of cooling before reprocessing.
2. [Bunn et al., 2003] also assumes 1 year of
reprocessing and 0.5 year of fuel fabrication
+ 0.5 year of storage of the fresh fuel;
[NEA, 2009] assumes only 0.5 year of reprocessing
and 0.5 year of fuel fabrication;
[NEA, 2002] assumes 2 years of storage of
the fresh fuel (including fabrication); [de
Roo and Parsons, 2009] assumes 1 year of
reprocessing, 0.5 year of fuel fabrication +
0.5 year of shipping and storage.
FR Metal Fuel Compositions for Various Conversion Ratios (equilibrium cycle)
CompoSitionS in %W oF the initial heavy metal load
FaSt reaCtor breeder
FaSt burner reaCtor
conversion ratio 1.23 0.0 0.5 0.75 1.0
load
aFter
diSCharGe load
aFter
CoolinG load
aFter
CoolinG load
aFter
CoolinG load
aFter
CoolinG
Tru 8.90 10.38 98.59 67.13 33.32 27.07 21.21 19.20 13.86 14.04
u 91.10 84.03 1.41 1.44 66.68 58.88 78.79 70.12 86.14 78.30
FP 0 5.60 0 31.43 0 14.05 0 10.68 0 7.66
Pu 8.67 10.15
Ma 0.23 0.23
sion ratio to 1.115, the installed capacity is only increased by a small amount, less than 5%.
Recalling that the total nuclear capacity in 2100 will be about 860 GWe, the share of fast
reactors is about 56% with the improved fuel requirements.
Startup of Fast Reactors with Enriched Uranium
One option to avoid the coupling of fast reactor startup with reprocessing of LWR spent
fuel is to start fast reactors with a core of enriched uranium rather than TRU. As can be
seen in the preceding results of the nuclear fuel cycle, the availability of TRU from LWRs
for the initial fast reactor core places an upper limit on the deployment rate of fast reactors.
Alternatively, starting fast reactors with enriched uranium, and multi-recycling of the resulting
TRU, may allow building a larger number of fast reactors, which in turn would save
uranium resources. If only fast reactor TRU was recycled, this strategy would obviate the
need for facilities to recycle LWR TRU.
Many experimental fast reactors were started using medium- and high-enriched uranium,
higher than the current limit on commercial reactor enrichment of 20% U-235— the
standard dividing enrichment level distinguishing LEU and HEU (weapons useable). Historically
it has been assumed that medium-enriched uranium or plutonium was required
to start a fast reactor. Core simulations at MIT show suitable performance for a sodium-
chapter 6: analysis of Fuel cycle options 93