The present disclosure relates to the field of reactor engineering technologies, and particularly to a spherical element detecting and positioning device. The spherical element detecting and positioning device includes a pressure-bearing casing, an internal member and an execution part; the pressure-bearing casing includes a tank body, one sphere inlet adapter pipe and two sphere outlet adapter pipe respectively arranged on the tank body; the internal member is arranged in the rotor counter-bored hole and includes a lining ring and a limit ring; and the execution part includes a turntable and two support lugs. The spherical element detecting and positioning device provided by the present disclosure can achieve triple functions of performing automatic material separation, precise positioning and directional conveyance of spherical elements, has compact structure and simple control, and can meet the operation reliability and maintainability requirements for long-term and intermittent operation under the strong radioactive environment.

The present disclosure relates to the field of reactor engineering technologies, and particularly to a spherical element detecting and positioning device. The spherical element detecting and positioning device includes a pressure-bearing casing, an internal member and an execution part; the pressure-bearing casing includes a tank body, one sphere inlet adapter pipe and two sphere outlet adapter pipe respectively arranged on the tank body; the internal member is arranged in the rotor counter-bored hole and includes a lining ring and a limit ring; and the execution part includes a turntable and two support lugs. The spherical element detecting and positioning device provided by the present disclosure can achieve triple functions of performing automatic material separation, precise positioning and directional conveyance of spherical elements, has compact structure and simple control, and can meet the operation reliability and maintainability requirements for long-term and intermittent operation under the strong radioactive environment.

The present application relates to a spherical object falling buffer device including a flow-limiting pipe assembly and a central column assembly; wherein the flow-limiting pipe assembly includes a flow-limiting pipe, a redirecting joint and a sphere outlet pipe; a diameter of the flow-limiting pipe is greater than that of the sphere outlet pipe, and an inner surface of the redirecting joint is a conical surface; the central column assembly includes at least a central column arranged in the flow-limiting pipe; a flow-guiding region is provided between the flow-limiting pipe and the central column, and a plurality of gravity flow guide grooves are provided on an outer peripheral surface of the central column. The spherical object falling buffer device may restrict, guide and buffer spherical objects during falling, and avoids collision damage of the spherical objects or the stock bin due to the excessive falling speed of the spherical objects.

A nuclear fuel element is provided. The nuclear fuel element includes a porous support. The porous support includes a ligament and defines a pore adjacent to the ligament. The ligament has an interior surface spaced from the pore. The interior surface defines a void. The porous support includes silicon carbide. The nuclear fuel element includes a nuclear fuel material disposed in the pore. The nuclear fuel material includes a moderator and tri-structural isotropic (TRISO) particles. Another nuclear fuel element is provided. The nuclear fuel element includes a porous support. The porous support includes a ligament and defines a pore adjacent to the ligament. The ligament has an interior surface spaced from the pore. The interior surface defines a void. The ligament includes the nuclear fuel material. The nuclear fuel element includes a facesheet overlying the porous support and defines a hole. The hole is in fluid communication with the void. The nuclear fuel material includes a nuclear fuel.

A nuclear reactor structure configuring a pebble accommodating space of a pebble bed type nuclear reactor includes a core material including graphite and a ceramic/ceramic composition material covering a surface of the core material. According to a core material processing step (A) of processing the core material including graphite into a quadrangular prism, a bottom surface of which is an approximately isosceles trapezoid, a step (B) of obtaining a base material by covering the core material with an aggregate including a ceramic fiber, and a CVD step (C) of putting the base material into a CVD reactor and forming a SiC matrix in gaps of the aggregate, thereby forming a ceramic/ceramic composite material on a surface of the core material, the nuclear reactor structure capable of enhancing durability, preventing cracking, etc. from occurring, and preventing exposure of graphite as the core material from occurring, can be provided.

A system for transferring heat from a nuclear reactor comprises a nuclear reactor comprising a nuclear fuel and a reactor vessel surrounding the nuclear reactor and a heat transfer system surrounding the nuclear reactor. The heat transfer system comprises an inner wall surrounding the nuclear reactor vessel, first fins coupled to an outer surface of inner wall, an outer wall between the inner wall and a surrounding environment, and second fins coupled to an inner surface of the outer wall and extending in a volume between the outer surface of the inner wall and the inner surface of the outer wall, the outer surface of the inner wall and the first fins configured to transfer heat from the nuclear reactor core to the second fins and the inner surface of the outer wall by thermal radiation. The heat transfer system may be directly coupled to the nuclear reactor vessel, or may be coupled to an external reflector surrounding the nuclear reactor vessel. Related heat transfer systems and systems for selectively removing heat from a nuclear reactor are disclosed.

A method of manufacturing nuclear fuel elements may include: forming a graphite base portion of the fuel element; depositing a first layer of graphite spheres on the base portion; depositing a first layer of fuel, burnable poison and/or breeder particles on the first layer of graphite spheres; forming a second layer of graphite spheres on the first layer of particles; depositing a second layer of fuel, burnable poison and/or breeder particles on the second layer of graphite spheres; and forming a graphite cap portion of the fuel element. Fuel, burnable poison and/or breeder particles of the first layer may be are spaced apart by substantially the same distance, and fuel, burnable poison and/or breeder particles of the second layer may be spaced apart by substantially the same distance. The fuel element may be a spherical fuel pebble. The fuel particles may be tri-structural-isotropic (TRISO) particles without an overcoat.

A method of manufacturing nuclear fuel elements may include: forming a graphite base portion of the fuel element; depositing a first layer of graphite spheres on the base portion; depositing a first layer of fuel, burnable poison and/or breeder particles on the first layer of graphite spheres; forming a second layer of graphite spheres on the first layer of particles; depositing a second layer of fuel, burnable poison and/or breeder particles on the second layer of graphite spheres; and forming a graphite cap portion of the fuel element. Fuel, burnable poison and/or breeder particles of the first layer may be are spaced apart by substantially the same distance, and fuel, burnable poison and/or breeder particles of the second layer may be spaced apart by substantially the same distance. The fuel element may be a spherical fuel pebble. The fuel particles may be tri-structural-isotropic (TRISO) particles without an overcoat.

A method of manufacturing nuclear fuel elements may include: forming a base portion of the fuel element by depositing a powdered matrix material including a mixture of a graphite material and a fibrous material; depositing particles on the base portion in a predetermined pattern to form a first particle layer, by controlling the position of each particle in the first particle layer; depositing the matrix material on the first particle layer to form a first matrix layer; depositing particles on the first matrix layer in a predetermined pattern to form a second particle layer by controlling positions of each particle in the second particle layer; depositing the matrix material on the second particle layer to form a second matrix layer; and forming a cap portion of the fuel pebble by depositing the matrix material. The particles in the first particle layer and the second particle layer include nuclear fuel particles.

A method of manufacturing nuclear fuel elements may include: forming a base portion of the fuel element by depositing a powdered matrix material including a mixture of a graphite material and a fibrous material; depositing particles on the base portion in a predetermined pattern to form a first particle layer, by controlling the position of each particle in the first particle layer; depositing the matrix material on the first particle layer to form a first matrix layer; depositing particles on the first matrix layer in a predetermined pattern to form a second particle layer by controlling positions of each particle in the second particle layer; depositing the matrix material on the second particle layer to form a second matrix layer; and forming a cap portion of the fuel pebble by depositing the matrix material. The particles in the first particle layer and the second particle layer include nuclear fuel particles.