Year
2015
Abstract
Recent improvements in the Gas Dynamic Trap-Neutron Source (GDT-NS) in Novosibirk has led to an evaluation of their technology for minor actinide transmutation and have projected a 15 MW fusion plasma with many of the resulting neutrons emitted into two fission blanket regions. This Russian developed technology has the potential to provide a more affordable approach towards meeting US treaty commitments regarding plutonium disposition. The subcritical blankets would operate in the fast neutron spectrum allowing for both metallic fuel and steel cladding, negating the presence of gallium, leading to decreased fuel manufacturing costs compared to the current mixed- oxide fuel approach. Furthermore, the blanket is able to operate with a uranium-free fuel leading to the same degradation in plutonium isotopics seen in the proposed Advanced Disposition Reactor (ADR) fuel, U-20Pu-10Zr, with a third less fission energy. The goal of this paper is to evaluate the feasibility of a GDT driven plutonium burner and the overall burner performance is largely impacted by two properties: the coupling between the fusion neutron source and the fission blanket and the blanket neutron multiplication. The coupling is a function of material selection and device geometry while the neutron multiplication is dependent on the fuel loading cycle. The latter component is especially impactful due to the asymptotic relationships as the neutron multiplication constant approaches one; a decrease in k-eff from 0.97 to 0.96 results in a 25% decrease in blanket power and, therefore, the isotopic degradation rate. The importance of this is somewhat unique for the proposed burner as the combination of a lack of fertile isotopes with a small initial fuel loading leads to comparatively rapid decreases in neutron multiplication. After maximizing the source / blanket coupling and minimizing burnup-related reactivity losses, the metrics set for the fast ADR are used to calculate an annual plutonium disposition rate.