This paper proposes a new strategy to introduce fusion reactors to the world. These require moderate changes to the design of current fusion reactors but add the functionality to transmute minor actinides. We perform neutron transport and burnup simulations to evaluate the effectiveness of the minor actinide transmutation system in which fusion neutron energy is rather moderate to reduce the heat load, and there is the possibility of using the Pu transmuted from minor actinides as a fertile fuel in a fast reactor. We also estimate the mass balance of a new nuclear fuel cycle with the introduction of fusion reactors.

The transmutation of minor actinides by fusion neutrons is very effective in providing support factor 5 when a 1-GW fusion reactor is used with a transmutation volume of 4% of the original blanket in the case of water coolant. The reduction in the tritium breeding ratio due to the introduction of the transmutation region is around 2% in the case of a water coolant.

A scenario to introduce the fusion reactors showed that 8.3-GW fusion reactors will operate to support 32 fast reactor plants of 1.5 GW(electric). The Pu generated from the fusion reactors includes 238Pu, so much so that the effective multiplication factor of fast reactors is reduced to around 1.01 and is kept greater than 1.005 for 600 days, which is preferable from the viewpoint of safety. The results indicate that by introducing a few fusion reactors, an option without the geological disposal of high-level wastes becomes available to make the fission fuel cycle system much more attractive.