MACROSCOPIC CROSS SECTIONS OF NEUTRON RADIATION CAPTURE BY Pb-208, U-238 AND Tc-99 NUCLIDES IN THE ACCELERATOR DRIVEN SUBCRITICAL CORE COOLED WITH MOLTEN Pb-208

摘要

In the paper macroscopic cross sections <σ(n,g)> for several isotopes: ~(208)Pb, ~(238)U, ~(99)Tc and natural mix of lead isotopes, ~(nat)Pb, averaged over neutron spectra of the accelerator driven subcritical core cooled with ~(nat)Pb or ~(208)Pb are given. It is shown that macro cross sections for a coolant from ~(208)Pb are by 6.2 times smaller than those for the coolant consisted from ~(nat)Ph. The economy of neutrons in the core cooled with molten ~(208)Pb can be used for reducing initial fuel load, increasing plutonium breeding and enhancing transmutation of such long lived fission products as ~(99)Tc. The values of macro cross sections calculated for ~(238)U and ~(99)Tc, equal to 0.6 and 0.8 barns, respectively, are comparable with the values of the same nuclide macro cross sections <σ(n,g)> for neutron spectrum of the fast reactor core cooled with sodium. Good neutron and physical features of molten ~(208)Pb permit to assume it as perspective coolant for fast reactors and accelerator driven systems.