The present disclosure relates to the technical field of reactor engineering, and particularly, to a nuclear power plant spent fuel negative pressure unloading system, comprising a fuel element transport pipe and a gas transport pipe. The fuel element transport pipe comprises a fuel element output pipe, a fuel element lifting pipe, and a fuel element unloading pipe connected in series. The fuel element unloading pipe is arranged obliquely downward in the direction of fuel element movement. The distal end of the fuel element unloading pipe is connected sequentially to fuel loading apparatus and a transfer apparatus. Two nozzles of the gas transport pipe are connected to set positions on the fuel element output pipe and the fuel element unloading pipe respectively. Gas driving mechanisms are connected to the gas transport pipe. An inlet of the gas driving mechanism is arranged at one end in proximity to the fuel element unloading pipe. The sealed system prevents significant oxidation of a spent fuel element due to high temperature, thus ensuring the integrity of the fuel element in the transfer apparatus, and the safety of the spent fuel unloading system can be ensured.

A system for continuously preparing coated particles in a large scale comprises: a coating furnace, a cooling facility, a solid by-product treatment device, and a gas by-product treatment device connected in sequence. The coating furnace is used for coating particles. The cooling facility is used for cooling the coated particles. The solid by-product treatment device is used for treating solid by-products generated in the coating furnace during the particle coating process. The gas by-product treatment device is used for treating gas by-products generated in the coating furnace during the particle coating process. The system for continuously preparing coated particles resolves the problem that a system in the prior art, aiming at batch production, has a time interval between two batches, wherein a temperature increase process and a temperature decrease process both exist, and is small in scale, does not completely break through laboratory research and cannot achieve real industrial continuous preparation.

A spherical fuel element forming apparatus comprises a fuel area forming system, a fuel-free area shaping system and a green sphere pressing system connected sequentially. The fuel area forming system is used for evenly mixing a core sphere matrix powder with nuclear fuel particles and then pressing the mixed core sphere matrix powder and nuclear fuel particles into core spheres. The fuel-free area shaping system is used for preparing a spherical fuel element from the core spheres covered by a fuel-free matrix powder. The green sphere pressing system is used for pressing the spherical fuel elements into green spheres. The spherical fuel element forming apparatus is distributed according to a technical process flow line operation, and is compact in structure and convenient to operate. Sphere greens after being finally pressed are high in sphericity, fuel element cost is lowered, and the finished product rate is high.

A spherical fuel element forming apparatus comprises a fuel area forming system, a fuel-free area shaping system and a green sphere pressing system connected sequentially. The fuel area forming system is used for evenly mixing a core sphere matrix powder with nuclear fuel particles and then pressing the mixed core sphere matrix powder and nuclear fuel particles into core spheres. The fuel-free area shaping system is used for preparing a spherical fuel element from the core spheres covered by a fuel-free matrix powder. The green sphere pressing system is used for pressing the spherical fuel elements into green spheres. The spherical fuel element forming apparatus is distributed according to a technical process flow line operation, and is compact in structure and convenient to operate. Sphere greens after being finally pressed are high in sphericity, fuel element cost is lowered, and the finished product rate is high.

Nuclear fuel elements may include: a fuel zone including fuel particles disposed in parallel layers in a matrix including graphite powder; and a shell comprising graphite and surrounding the fuel zone. The fuel particles may include fissile particles, burnable poison particles, breeder particles, or a combination thereof. The fuel zone may include a central region and a peripheral region surrounding the central region, and a fuel particle density of the peripheral region may be greater than a fuel particle density of the central region.

Nuclear fuel elements may include: a fuel zone including fuel particles disposed in parallel layers in a matrix including graphite powder; and a shell comprising graphite and surrounding the fuel zone. The fuel particles may include fissile particles, burnable poison particles, breeder particles, or a combination thereof. The fuel zone may include a central region and a peripheral region surrounding the central region, and a fuel particle density of the peripheral region may be greater than a fuel particle density of the central region.

A method of mass producing nuclear fuel elements may include: forming a graphite base portion of the fuel elements; repeatedly performing a sequence of operations comprising depositing a uniform graphite layer over a previous layer, depositing a layer of particles on the uniform graphite layer within a fuel zone diameter, so that the particles are spaced apart in a predefined pattern, and applying a binder using additive manufacturing methods to bind each layer with successively increasing and then decreasing diameters to form a central portion of fuel elements including a fuel-containing fuel zone; and repeatedly performing a sequence of operations comprising forming a uniform graphite layer on a previous layer and applying a binder using additive manufacturing methods to bind each layer with successively decreasing diameters to form a cap portion of fuel elements. The particles may include one or more of a nuclear fuel material, burnable poison material, or breeder material. The fuel particles may be tri-structural-isotropic (TRISO) particles that do not have an overcoat.

A method of mass producing nuclear fuel elements may include: forming a graphite base portion of the fuel elements; repeatedly performing a sequence of operations comprising depositing a uniform graphite layer over a previous layer, depositing a layer of particles on the uniform graphite layer within a fuel zone diameter, so that the particles are spaced apart in a predefined pattern, and applying a binder using additive manufacturing methods to bind each layer with successively increasing and then decreasing diameters to form a central portion of fuel elements including a fuel-containing fuel zone; and repeatedly performing a sequence of operations comprising forming a uniform graphite layer on a previous layer and applying a binder using additive manufacturing methods to bind each layer with successively decreasing diameters to form a cap portion of fuel elements. The particles may include one or more of a nuclear fuel material, burnable poison material, or breeder material. The fuel particles may be tri-structural-isotropic (TRISO) particles that do not have an overcoat.

Apparatus for the production of carbon dioxide from limestone includes a nuclear reactor (10) for generating heat and a rotary kiln (12). The rotary kiln (12) has an inlet (28) for the introduction of limestone and an outlet (30) for the release of carbon dioxide. A heat transfer arrangement is provided for transferring heat from the nuclear reactor (10) to the interior of the rotary kiln (12). The heat transfer arrangement includes feed and return primary conduits (17,18) for passing a heat transfer fluid (14) through the nuclear reactor (10) so that heat may be extracted from the nuclear reactor (10) for transfer to the interior of the rotary kiln (12). Limestone in the rotary kiln (12) is thereby heated to a temperature sufficient for the release of carbon dioxide.

Apparatus for the production of carbon dioxide from limestone includes a nuclear reactor (10) for generating heat and a rotary kiln (12). The rotary kiln (12) has an inlet (28) for the introduction of limestone and an outlet (30) for the release of carbon dioxide. A heat transfer arrangement is provided for transferring heat from the nuclear reactor (10) to the interior of the rotary kiln (12). The heat transfer arrangement includes feed and return primary conduits (17,18) for passing a heat transfer fluid (14) through the nuclear reactor (10) so that heat may be extracted from the nuclear reactor (10) for transfer to the interior of the rotary kiln (12). Limestone in the rotary kiln (12) is thereby heated to a temperature sufficient for the release of carbon dioxide.