A new fission-fusion hybrid reactor will be assembled at Russia’s Kurchatov Institute by the end of 2018, Peter Khvostenko, scientific adviser of the Kurchatov complex on thermonuclear energy and plasma technologies, announced on 14 May. The physical start-up of the facility is scheduled for 2020.
The hybrid reactor combines the principles of thermonuclear and nuclear power – essentially a tokamak fusion reactor and a molten salt fission reactor. Neutrons produced in a small tokamak will be captured in a molten salt blanket located around tokamak. The facility will use Thorium as a fuel, which is cheaper and more abundant than uranium. Moreover, unlike a fusion reactor, a hybrid will not require super high temperatures to generate energy.
Hybrid reactors reduce the impact of the nuclear fuel cycle on the environment. The concept combines conventional fission processes and fusion reactor principles, comprising a fusion reactor core in combination with a subcritical fission reactor. The results of the fusion reaction, which would normally be absorbed by the cooling system of the reactor, would feed into the fission section, and sustain the fission process. Thorium in a molten salt blanket will enable breeding or uranium-233.
Some of the expected advantages include:
- Utilization of actinides and transmutation from long-lived radioactive waste;
- An increase in energy recovered from uranium by a large factor;
- The inherent safety of the system, which can be shut down rapidly; and
- High burnup of fissile materials leaving few by-products.
The hybrid fission-fusion reactor is seen as a near-term commercial application of fusion pending further research on pure fusion power systems.