Kakaiev A. Superslow wave neutron-nuclear burning by thermal neutrons in thorium-uranium fissionable medium

The dissertation is devoted to research and definition of conditions of existence of wave neutron-nuclear burning in thorium fuel for neutrons with energies in the range 0,015 eV - 1 MeV. The generalized criterion of the existence of wave regimes of neutron-nuclear burning for thorium fission media is formulated. The fulfillment of the criterion of wave neutron-nuclear burning for thorium-uranium fuel with the degree of uranium-235 enrichment from 0.5% to 2% in the region of neutron energies 0.015 - 10.00 eV has been studied and proved. The influence of 233Pa on the criterion of wave neutron-nuclear burning in thorium-uranium fuel was found and it was shown that at a concentration of protactinium-233 nuclei less than 1% of the total number of fission nuclei wave nuclear burning is possible in the range of thermal neutrons. The conditions for fulfilling the criterion of wave neutron-nuclear burning for thorium-uranium fuel having the geometric shape of a cylinder and a sphere are investigated, and it is determined that on thermal neutrons the criterion is fulfilled at a minimum cylinder radius of 6 cm and a sphere of 10 cm. A system of kinetic equations for superslow wave neutron-nuclear burning in thorium-uranium fuel is formulated. Based on mathematical modeling, the dynamics of formation and maintenance of wave neutron-nuclear burning of thorium-232 and thorium-232 enriched (0.5%) with uranium-235 or plutonium-239 by duration of 360 days was obtained. The possibility of creating a thermal wave nuclear reactor on thorium-uranium fuel has been proved.