摘要:
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.
摘要:
A computerized system for modeling reactor fuel element and fuel design to determine the thermo-mechanical performance thereof includes a processor coupled to memory, the memory configuring the processor to execute a fuel element analysis and an output configured to communicate data that describes the thermo-mechanical performance of the fuel element and fuel design based on the fuel element performance analysis. The processor is configured to estimate the mechanical behavior of a fuel by creating separate variables for the open and closed porosity components, conducting a routine for the open and closed porosity components that processes the current state of the fuel and updates the current state and forces of each of the open and closed porosity components, and combining the updates for the current state and forces according to a weighting; and estimate the creep and swelling behavior of a cladding.
摘要:
Porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's), and to processes for fabricating them. Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, the nuclear fuel may be deposited inside of a highly porous skeletal structure made of, for example, reticulated vitreous carbon foam.
摘要:
A dual-cooled nuclear fuel rod and a method of manufacturing the same are provided. The nuclear fuel rod includes an outer cladding tube having a circular cross section, an inner cladding tube having an outer diameter smaller than an inner diameter of the outer cladding tube, and a length longer than the outer cladding tube, and located in parallel in the outer cladding tube, a pellet charged in a space between the outer and inner cladding tubes and generating energy by nuclear fission, and first and second end plugs coupling opposite ends of the outer cladding tube to stepped outer joints formed on outer circumferences of first ends thereof and coupling opposite ends of the inner cladding tube to stepped inner joints formed on inner circumferences of the first ends thereof.
摘要:
A nuclear fuel pellet design that is a cylindrical axial profile with either a larger radius or conical shaped ends such that the as built diameter at the ends of the pellet are slightly smaller than at the middle and at normal operating conditions, the diameter at the ends is nearly the same as at the middle. Preferably, there are short chamfers at the axial ends of the pellet.
摘要:
The invention relates to a nuclear fuel cladding totally or partially made of a composite material with a ceramic matrix containing silicon carbide (SiC) fibers as a matrix reinforcement and an interphase layer provided between said matrix and said fibers, the matrix including at least one carbide selected from titanium carbide (TiC), zirconium carbide (ZrC), or ternary titanium silicon carbide (Ti3SiC2).When irradiated and at temperatures of between 800° C. and 1200° C., said cladding can mechanically maintain the nuclear fuel within the cladding while enabling optimal thermal-energy transfer towards the coolant.The invention also relates to a method for making the nuclear fuel cladding.
摘要翻译:本发明涉及一种全部或部分由复合材料制成的核燃料包层,该复合材料具有含有碳化硅(SiC)纤维作为基质增强层的陶瓷基体和在所述基质和所述纤维之间提供的界面层,该基质包括至少一种碳化物 选自碳化钛(TiC),碳化锆(ZrC)或三元钛碳化硅(Ti 3 SiC 2)。 当照射并且在800℃和1200℃之间的温度下时,所述包层可以将核燃料机械地保持在包壳内,同时能够使朝向冷却剂的最佳热能传递。 本发明还涉及制造核燃料包层的方法。
摘要:
Among fuel rods constituting a fuel assembly, Gd compound oxide is added to low Gd containing fuel rods that containing uranium dioxide of which enrichment exceeds 5 wt %. The Gd compound oxide is oxide of gadolinium and rare earth element A except for gadolinium and is expressed as a chemical formula A1-xGdxO2-0.5x or a chemical formula A1-xGdxO1.5. As the rare earth element A, cerium Ce, lanthanum La or erbium Er can be used.
摘要:
The bar-code printing method of the present invention comprises a step of irradiating the circumferential surface of a metal tube with laser beams so as to make at least one group of thin elementary lines arranged in parallel with each other at intervals. The width of the intervals is determined so that each group of elementary lines can be detected as one of the thick lines contained in the bar-code.
摘要:
System and method for engraving an image on a workpiece, such as a nuclear steam generator tubesheet. The system includes a laser assembly for generating a pulsed laser beam to engrave the image adjacent a target position on the workpiece. A positioning mechanism is connected to the laser assembly for positioning the laser assembly with reference to the target position. A controller is electrically connected to the positioning mechanism for controlling the positioning mechanism in order to controllably position the laser assembly at the target position and for verifying the image engraved at the target position. A computer is electrically connected to the controller for receiving the verified image. The computer is also electrically connected to the laser assembly for operating the laser assembly so that the laser beam emitted thereby engraves the image on the tubesheet at the target position.
摘要:
A nuclear fuel element for use in power-producing nuclear reactors, comprising a circular metal cladding tube containing sintered cylindrical oxide fuel pellets, the tube being formed internally with a substantially cylindrical inner surface having a plurality of longitudinal ribs forming axially extending channels. The fuel pellets have chamfered endfaces creating toroidal spaces at the adjoining ends of the fuel pellets, the ratio of axial channel to toroidal space volumes including any pellet dishing being at most about one (1);a process for the manufacture of such fuel element.