Evaluation of the applicability of plutonium transmuted from minor actinides by fusion reactor as fertile fuel in boiling water reactor

This study proposes to make effective use of plutonium transmuted from minor actinides (MA) by fusion reactors as fertile fuel in a light water reactor (LWR). The plutonium transmuted from MA, particularly Pu-238, has a large neutron capture cross section and becomes fissile Pu-239 by the reaction. If the plutonium transmuted from MA is loaded into LWR appropriately, there is a possibility to maintain a constant effective multiplication factor. This study evaluated the effects of the plutonium transmuted from MA on a full MOX boiled water reactor (BWR) core by Monte Carlo-based neutron transport and burnup calculation. We revealed that some fuel assemblies achieved the effective multiplication factor is greater than 1.0 and its decrease was significantly small (-0.013) during 400 days operation. However, under this condition, the power peaking factor was 1.4, which should be unacceptable from the viewpoint of thermal design. Inventories of heavy nuclides in fuel cycles was evaluated using a simple diagram and its result indicated that the accumulation of MA in the fuel cycle was reduced by introducing the MA transmutation and the Pu recycle system. Furthermore, the amount of MA production and MA transmutation are balanced by introducing two fusion reactors with 3 GW thermal output into the fuel cycle, and the MA inventory was equilibrated.