| dc.description.abstract | This study compares three fuel types using neutronic analysis for use in a
sodium-cooled fast reactor (SFR) design with a modified CANDLE (Constant
Axial shape of Neutron flux, nuclide densities, and power shape During Life of
Energy production) radial shuffling strategy. SFR is one type of generation IV
reactor that is currently under investigation for commercial implementation.
In this study, the SFR design utilizes natural uranium as the fuel input. The
designed reactor core has a two-dimensional cylindrical geometry for each fuel
mixed oxide (MOX), uranium-plutonium nitride ([U-Pu]N), and uranium plutonium zirconium ([U-Pu]Zr). A radial shuffling strategy, using natural
uranium as the fuel input, is applied to the SFR to manage the nuclear fuel
burn-up process of the long-life reactor. This strategy is called the modified
CANDLE burn-up scheme. The reactor core is divided into 10 regions with
equal volume to represent the 10 years that the reactor operates without
refueling. Initially, the first (innermost) region of the reactor core is filled with
natural uranium fuel. The result of the burn-up from the first region is then
shuffled into the second region. The third region is the result of the burn-up
that is shuffled from the second region, and so on. This mechanism only
requires natural uranium as the input for each 10-year fuel cycle. In this study,
the fuel movement scheme is examined for three fuels. Global neutronic
parameters, such as the multiplication factors and burn-up analyses, are
observed and optimized. Overall, for an output power of 500 MWth and an
active core radius of 110 cm and height of 210 cm, the study indicates that (U Pu)N is the optimal fuel to be applied in the SFR with a modified CANDLE
burn-up scheme. (U-Pu)Zr reaches a critical condition at an output power of
500 MWth with an active core radius of 130 cm and a height of 210 cm;
whereas criticality for MOX is achieved at an output power of 1500 MWth with
an active core radius of 210 cm and a height of 210 cm. | en_US |
