Nuclear power generation system utilizing thermal expansion in metallic members to move a neutron reflector

A nuclear power generation system comprising

• a nuclear reactor,
• a heat exchanging system for exchanging heat between a primary coolant for cooling the nuclear reactor and a secondary coolant comprised of carbon dioxide or light water, and
• a turbine power generation system for generating power using heat of the secondary coolant;
• the nuclear reactor comprising:
• a reactor core having fuel assemblies comprising a plurality of fuel rods, the fuel rods comprising cladding tubes containing metallic fuel including at least one selected from uranium-235, uranium-238 and plutonium-239;
• a reactor vessel containing the reactor core;
• the primary coolant being one of metallic sodium, lead, and lead-bismuth loaded into the reactor vessel and heated by the reactor core;
• and
• at least one neutron reflector disposed around the reactor core,
• wherein the at least one neutron reflector disposed around the reactor core has neutron reflection efficiency for achieving criticality in the reactor core with an effective multiplication factor of neutrons emitted from the reactor core being maintained at or above about 1, and
• wherein the at least one neutron reflector is coupled to metallic members having a coefficient of thermal expansion greater than a coefficient of thermal expansion of the at least one neutron reflector, and the neutron reflection efficiency of the at least one neutron reflector is changeable utilizing displacement thereof due to dimensional change of the metallic members coupled thereto in accordance with changes in the temperature in the reactor vessel, thereby achieving load following control.