The FuTure oF nuclear Fuel cycle - MIT Energy Initiative

A proper representation of the chain of costs in a full actinide recycling system is very complex.
Each pass through a reactor changes the isotopic composition of the fuel. In particular,
the vector of uranium and transuranic elements is changing with each pass, only gradually
approaching an equilibrium vector. The isotopic composition determines the neutronic behavior
which must be taken into account in fabricating the new fuel at each stage, changing
the costs at each pass. A proper calculation of the levelized cost for the cycle as a whole must
account for the complete profile of these changing costs through time, requiring a unique
assessment of C jt for each j.
The levelized cost formula in equation (7A.6) can be greatly simplified if we assume that the
vector of transuranics is constant through all of the fast reactor cycles, as if the equilibrium
vector were reached at the extraction of the transuranics from the light water reactor. We
then assume that all of the various costs at each fast reactor cycle scale according to the
transuranics mass ratio, q 2/q 1
, which measures the quantity of the transuranics exiting the
cycle relative to the quantity entering the cycle. This ratio is linked to but different from the
conversion ratio by which fast reactors are usually labeled. 5 Under this constant transuranics
vector assumption, the present value of the costs at each pass through a fast reactor is
a simple scaling of the costs at the first pass in fast reactors, with the scaling factor being
(7A.7)
Consequently, the infinite chain of distinct cost calculations can be reduced to one involving
only two cycles with different cost elements:
Assuming a