A reflector assembly for a molten chloride fast reactor (MCFR) includes a support structure with a substantially cylindrical base plate, a substantially cylindrical top plate, and a plurality of circumferentially spaced ribs extending between the base plate and the top plate. The support structure is configured to encapsulate a reactor core for containing nuclear fuel. The MCFR also includes a plurality of tube members disposed within the support structure and extending axially between the top plate and the bottom plate. The plurality of tube members are configured to hold at least one reflector material to reflect fission born neutrons back to a center of the reactor core.

A reflector assembly for a molten chloride fast reactor (MCFR) includes a support structure with a substantially cylindrical base plate, a substantially cylindrical top plate, and a plurality of circumferentially spaced ribs extending between the base plate and the top plate. The support structure is configured to encapsulate a reactor core for containing nuclear fuel. The MCFR also includes a plurality of tube members disposed within the support structure and extending axially between the top plate and the bottom plate. The plurality of tube members are configured to hold at least one reflector material to reflect fission born neutrons back to a center of the reactor core.

A nuclear power generation system being safe and easily controlled by load following. The nuclear power generation system has a nuclear reactor employing a load following control method. The reactor includes: a fuel assembly reactor core having metallic fuel containing at least one selected from uranium-235, uranium-238 and plutonium-239; a reactor vessel containing the reactor core; metallic sodium loaded into the reactor vessel and heated by the reactor core; and a neutron reflector for achieving criticality in the reactor core with effective multiplication factor of neutrons emitted from the reactor core being maintained at or above about 1. The neutron reflector is coupled to spring or spiral metallic members and utilizing heat deformation in the metallic members due to the temperature in coolant metallic sodium to control the fast neutron reflection efficiency of the neutron reflector.

A nuclear power generation system being safe and easily controlled by load following. The nuclear power generation system has a nuclear reactor employing a load following control method. The reactor includes: a fuel assembly reactor core having metallic fuel containing at least one selected from uranium-235, uranium-238 and plutonium-239; a reactor vessel containing the reactor core; metallic sodium loaded into the reactor vessel and heated by the reactor core; and a neutron reflector for achieving criticality in the reactor core with effective multiplication factor of neutrons emitted from the reactor core being maintained at or above about 1. The neutron reflector is coupled to spring or spiral metallic members and utilizing heat deformation in the metallic members due to the temperature in coolant metallic sodium to control the fast neutron reflection efficiency of the neutron reflector.

A molten salt reactor includes a containment vessel, a reactor core, a neutron reflector spaced from the containment vessel, and liquid fuel enclosed within the core. The liquid fuel is comprised of a nuclear fission material dissolved in a molten salt. A heat exchanger is positioned external to the containment vessel. A plurality of heat transfer pipes are provided for transferring heat from the core to the heat exchanger. Each pipe has a first and a second end. The first end of each pipe is positioned within the reactor core for absorbing heat from the fuel. The heat exchanger receives the second end of each heat transfer pipe. At least two or more reactor shut down systems are provided. At least one shut down system may be a passive system and at least one or both shut down systems may be an active or a manually operated system.

Engineering safety systems always have insufficiencies in terms of safety, and construction of a complete safety system causes installation costs for the safety system to become very high. Provided is a small nuclear reactor HAVING a load following control system in which a nuclear reaction in the nuclear reactor is naturally controlled by the generated heat, the small nuclear reactor being provided with: a reactor core provided with a plurality of fuel assemblies of metallic fuels containing uranium (U) 235, 238 and/or plutonium (Pu) 239; a primary coolant comprising a liquid metal; a neutron reflector which serves to control the nuclear reaction in the reactor core and is disposed to enclose the periphery of the reactor core; and a mechanism which contains a liquid or a gas having an expansion coefficient greater than that of the neutron reflector, converts the coefficient of volumetric expansion into an amount of linear thermal expansion, and, by using same, moves the neutron reflector or adjusts the spacing between the plurality of fuel assemblies.

Engineering safety systems always have insufficiencies in terms of safety, and construction of a complete safety system causes installation costs for the safety system to become very high. Provided is a small nuclear reactor HAVING a load following control system in which a nuclear reaction in the nuclear reactor is naturally controlled by the generated heat, the small nuclear reactor being provided with: a reactor core provided with a plurality of fuel assemblies of metallic fuels containing uranium (U) 235, 238 and/or plutonium (Pu) 239; a primary coolant comprising a liquid metal; a neutron reflector which serves to control the nuclear reaction in the reactor core and is disposed to enclose the periphery of the reactor core; and a mechanism which contains a liquid or a gas having an expansion coefficient greater than that of the neutron reflector, converts the coefficient of volumetric expansion into an amount of linear thermal expansion, and, by using same, moves the neutron reflector or adjusts the spacing between the plurality of fuel assemblies.

Nuclear propulsion fission reactor structure has an active core region including fuel element structures, a reflector with rotatable neutron absorber structures (such as drum absorbers), and a core former conformal mating the outer surface of the fuel element structures to the reflector. Fuel element structures are arranged abutting nearest neighbor fuel element structures in a tri-pitch design. Cladding bodies defining coolant channels are inserted into and joined to upper and lower core plates to from a continuous structure that is a first portion of the containment structure. The nuclear propulsion fission reactor structure can be incorporated into a nuclear thermal propulsion engine for propulsion applications, such as space propulsion.

A core of a fast reactor including a sodium plenum installed above a core fuel, which is capable of reliably reducing a void reactivity, and an operation method thereof are provided. The core of a fast reactor including the sodium plenum installed above the core fuel is characterized in that a tip of a primary control rod is inserted into a core fuel region, and a tip of a backup control rod is arranged above an upper end of the core fuel region for operation.

A commercial nuclear fuel system includes: a vessel that defines an inner volume; a reactor core positioned within the inner volume; and a plurality of fuel pins disposed in the reactor core, each of the plurality of fuel pins comprising at least one hydride fuel element positioned in a cladding. The at least one hydride fuel element is enriched to twenty percent or less of fissile material. The fissile material comprises one or more of uranium-233, uranium-235, or plutonium-239. The fuel pins are positioned in a lattice within the reactor core. The vessel comprises a first vessel, and a second vessel is positioned within the first vessel and surrounds the plurality of fuel pins. At least one reflector is positioned within the first vessel and surrounds the plurality of fuel pins. A shielding assembly is positioned between the reflector and the first vessel.