Nuclear reactor system for extinguishing radioactivity

A nuclear reactor system including a nuclear reactor vessel,

• wherein the nuclear reactor vessel includes a first vessel serving as a region using fast neutrons, and a second vessel serving as a region using thermal neutrons in a nuclear reactor, energy of each thermal neutron being approximately 0.5 MeV or less, and the second vessel for the thermal neutrons is placed inside the first vessel for the fast neutrons or the first vessel for the fast neutrons is placed inside the second vessel for the thermal neutrons,
• the region using the fast neutrons includes
• a plurality of fuel assemblies, each fuel assembly being a bundle of 50 or more metal fuel rods, each metal fuel rod being obtained by inserting a metal fuel pin into a sheath made of stainless steel, the metal fuel pin having an alloy composition of zirconium (Zr) with uranium (U) and/or plutonium (Pu), and
• a liquid metal selected from metallic sodium (Na), Pb—Bi or Pb working as a primary coolant,
• a non-metallic material and radioactivity reducing assemblies are loaded in the region using the thermal neutrons, the non-metallic material being usable as a neutron moderator and as a secondary coolant, each radioactivity reducing assembly being obtained by putting a radioactive material into a sheath made of stainless steel or a Zr material, the radioactive material being obtained by processing minor actinide nuclides separated from spent fuel rods through reprocessing or radioactive nuclear fission products (FPs) separated and refined from the spent nuclear fuel, at least one selected from the group consisting of Se79, Sr90, Zr93, Tc99, Sn126, Cs135 and Cs137, being mixed and formed into a shape of a pellet or a pin, and
• the nuclear reactor system is configured
• to generate electricity by transferring thermal energy generated by the fast neutrons to a heat exchanger by use of the primary coolant, exchanging heat between the primary coolant and the secondary coolant in the heat exchanger, and thereafter supplying the thermal energy to a turbine system by use of the secondary coolant, and
• to simultaneously decrease a concentration of radionuclides by accelerating a rate of transmutation of radionuclides into stable nuclides by use of thermal neutrons generated by decelerating the fast neutrons.