Considerations for Fusion-Based Actinide Destruction

A fusion based actinide destruction system is advantageous because of higher actinide destruction efficiency and higher energy efficiency when compared to other destruction technologies. The unique neutron multiplication capability due to the n,2n reactions in blanket materials with 14 MeV D-T neutrons enhances further the performance efficiency.

Investigation of a high performance fusion based actinide destruction system was conducted. A self-cooled, actinide-carrying molten salt blanket can be designed to operate at a high sub-criticality factor of 0.95-0.96, with less than 0.4 wt% actinide concentration dissolved in the molten salt. The corresponding blanket energy multiplication is 160. Lithium-6, which is required for tritium breeding, can be used as a variable to shape the neutron spectrum and control the criticality factor, and thus to maintain a constant fission thermal power output from the actinide destruction plant.

Sub-criticality can be maintained in all cases of the actinide destruction plant, during normal operation and abnormal conditions.

A fusion device projected from a tokamak experiment can produce 30 MW fusion power, with a plasma amplification factor of 2. It is considered adequate to drive the sub-critical molten salt blanket. The total thermal fission power is about 4000 MW, which is able to destroy 1.6 metric tons of actinides annually when operating at full power.