Fuel Evolution in Hybrid Reactor Based on Thorium Subcritical Assembly with Open Trap as Fusion Neutron Source (Computer Simulations)

Abstract

Results of computer simulation of the fuel evolution in thorium nuclear cycle in a subcritical assembly in case of thorium-plutonium initial composition is presented in the paper. The simulation is conducted for specialized facility in which a long solenoid with hot plasma is situated inside of the subcritical fuel assembly. The plasma column produces additional neutrons due to D-D fusion reaction that are necessary for a fission reactor with this assembly. Total intensity of neutron emission over all plasma volume with the length of 3 m is N = 2 × 10¹⁶ neutrons per second. We have chosen the percentage of plutonium 5% in thorium-plutonium initial composition and in this case, the effective coefficient of neutron multiplication is 0.95, as shown by our simulation. The fuel evolution was calculated for duration of operation time 3000 days. As a result, we have demonstrated the decrease in the coefficient of neutron multiplication and in the power of the nuclear fission process in the described time. Results of simulations are discussed.