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Composite fuel model material with inert porous metal matrix and method for production thereof Invention relates to composite fuel model material consisting of a radiation-inert matrix and particles of a material which simulates nuclear fissile material (minor actinides). The material is characterised by that the inert matrix is made of porous metallic material and particles of the material which simulates nuclear fissile material uniformly coat the inner surface of the pores of the inert porous metal matrix and are in thermal contact with said matrix. The disclosed material is characterised by use of a metal matrix material with stronger contact of oxide particles with the porous metal matrix; the possibility of obtaining a given porosity of the porous metal matrix and degree of filling thereof with a fuel oxide (model oxide); the possibility of obtaining more accurate size tolerance when producing the porous metal matrix; high technological effectiveness of a separate process of producing a porous metal matrix, which enables to vary nuclear and physical characteristics by using different metals and alloys. |
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Method to manufacture pellet of nuclear ceramic fuel Pellet of nuclear fuel from uranium dioxide with homogeneously distributed oxides of aluminium and silicon and required content of aluminium from 0.005 to 0.03 wt % and silicon from 0.003 to 0.02 wt % is manufactured by introduction of a master powder of uranium protoxide-oxide U3O8 at the stage of preparation of the pressed powder in the amount of up to 30 wt %. At the same time the master powder is prepared in accordance with the ADU-process from a solution of uranyl nitrate containing aluminium and silicon in quantities from 0.05-0.3 wt %. |
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Active zone includes a fission initiator that includes fissionable and fertile materials, which provides initiation of a running wave and setting value keff that is equal at least to 1. Active zone is made so that it is possible to remove the fission initiator. Active zone can be made so that concentration of nuclear material in the space can be changed. |
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Manufacturing method of ceramic fuel pellets for fuel elements of nuclear reactor Pellets are pressed in two stages; at that, first, pressing of workpiece of internal core of pellet with axial hole is performed from moulding powder of highly-enriched uranium dioxide UO2, which contains alloying additives, by using press mould of smaller diameter. Then, obtained workpiece is put into press mould of larger diameter; after that, the gap formed between workpiece and internal wall of press mould is filled with moulding powder from low-enriched uranium dioxide UO2 for creation of outer layer of pellet and the second pressing stage is performed. It is proposed to obtain moulding powder of low-enriched uranium dioxide UO2 by using water technology including preparation of uranyl nitrate solution, two-stage deposition of ammonium polyuranate with hydrogen nitride, calcination of deposit, and reduction of monoxide-oxide to uranium dioxide UO2. Size of granules of low-enriched powder of UO2 uranium dioxide shall be less than 100 mcm. |
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Invention can be used to produce heat resistant compounds based on mixed oxides, nitrides or carbides of actinides. A stabilising monovalent cation consisting of oxygen, carbon, nitrogen and hydrogen atoms only or a compound such as a salt which forms the said cation, is added to one or more solutions of actinide(s) containing at least one actinide An1 and at least one actinide An'1. A solution or mixture consisting of at least an actinide An1 with oxidation state (IV), at least one actinide An'1 with oxidation state (III) and the said stabilising monovalent cation is obtained. A solution of oxalic acid or one of its salts or derivative of that salt is added to the obtained mixture, resulting in simultaneous precipitation of said actinides An1 (IV) and An'1 (III), as well as a portion of the stabilising monovalent cation from the said mixture. The obtained precipitate is calcined. |
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Invention relates to nuclear engineering, particularly to design of fuel elements and working holders assembled from the said fuel elements, used in water-cooled nuclear power reactors with heat power ranging from 1150 MW to 1700 MW. The fuel element of a water-cooled power reactor has cylindrical shell with end caps and a fuel column made from nuclear fuel tablets inside the shell. The length LFC of the fuel column ranges from 2.480 m to 2.700 m. Total length Lcap of parts of the end caps protruding from the cylindrical shell is not less than 5·10-3 m. The working holder of such a reactor has a head, a tail and a bundle of fuel elements with a fuel column. The ratio of the length LFC of the fuel column to the dimension LT between the upper end of the head and the lower end of the spherical surface of the tail ranges from 0.8276 to 0.9000. The length LH of the head ranges from 120 10-3 m to 163 10-3 m. The distance LT from the lower end of the spherical surface to the upper end of the tail ranges from 90 10-3 m to 238 10-3 m. The water-cooled power reactor with heating power ranging from 1150 MW to 1700 MW has a core made from the working holders, a moving plate and a bottom plate of the core barrel with mounting sockets for tails of the working holders. At least one working holder with the design given above is fitted in the core. |
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Invention refers to nuclear engineering and namely to fuel elements design, which are used for forming active zones of nuclear reactors, in particular, for high energy intensive active zones of research reactors. Fuel element has cruciform cross section. Fuel element blades are narrowed at the bottom and widened in central portion. On the blade end a spacer protrusion can be made. |
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Investigation method of radiation behaviour of nuclear reactor minute particles Invention refers to nuclear power engineering, and namely to investigation methods of minute particles of high-temperature gas cooled reactors. Investigation method of radiation behaviour of nuclear reactor minute particles consists in radiation of samples with high energy ions with subsequent isothermal annealing at temperature of 1500°C and more and analysis of samples prior to and after radiation. Samples made in the form of minute particle simulators with protective coverings and hemispheres prepared therefrom are pressed into matrix coal graphite composition thus forming a disc. Samples are located in the disc as a monolayer in a near-surface layer. Simulators of minute particles contact one of two flat disc surfaces. Hemispheres are led as equatorial sections to the same surface. Carbon microspheres containing stable isotopes of fission products and calcium phosphates are used as simulators of minute particles. Analysis of radiation damages is carried out by comparing structures of protective coverings on simulators of minute particles and protective coverings on hemispheres of simulators of minute particles. |
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Fuel element is used in power reactors of low capacity on thermal neutrons to increase reliability and energy production. Nuclear reactor fuel element comprises shell with end plugs, core in the form of nuclear fuel particles distributed in matrix, compensator installed inside shell in the area of fuel element active part with the help of spacer component, compensator is arranged with the area of cross section in the range from 0.1 to 0.3 of fuel element cross section area, nuclear fuel particles are made in the form of granules from uranium dioxide with size from 0.2 to 1.0 mm and porosity from 3 to 6%, uranium density in core is specified from 5.5 to 6.5 g/cm3, total mass of uranium in fuel element is specified from 100 to 210 g, compensator is made from thin-walled tight gas-filled tube, compensator cross section is made in the form of cross with two axes of symmetry and rounded ribs and cavities. |
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Proposed nuclear fuel has regularly disposed large spherical particles of U-Mo or U-Mo-X stable gamma-phase alloy. Diameter of particles uniformly disposed in at least one additional layer on aluminum shell ranges between 300 and 700 μm. Proposed method for producing platy nuclear fuel includes production of stable gamma-phase spherical particles of alloy U-Mo or U-Mo-X, disposition of particles on aluminum shell, application of aluminum powder onto product obtained, and rolling. |
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Method for recovering serviceability of nuclear reactor fuel assembly subchannel Proposed method for recovering serviceability of nuclear reactor fuel assembly subchannel includes reactor shutting down, dismounting of standard floor blocks from subchannel, and removal of fuel assembly. Process channel is checked for serviceability. Channel is visually inspected within reactor for integrity and channel inner diameter profile is measured. Then process channel pre-removal operations are made. Process channel is removed from subchannel and placed in storage. Construction clearance between process channel and graphite stacking is recovered by calibrating graphite column including finishing of central bore internal diameter to desired size and expansion device segment is installed between guard plate and top graphite block. Graphite column is checked for condition by inspecting inner surface of column. Telescopic joint height and inner diameter of graphite column central bore are measured. Then process channel removed earlier and found serviceable by its check results is reinstalled in fuel assembly subchannel. After that final mounting operations are conducted including welding of process channel to adjacent structures and formation of nuclear reactor subchannel. |
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Method for producing fuel composition for nuclear reactor Can of desired size is filled with finely dispersed fuel and in addition with material forming solid matrix at temperature equal to or higher than fuel melting point. This can filled with finely dispersed fuel and material forming solid matrix is heated to temperature equal to or higher than fuel melting point is heated and cooled down. |
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Heat-generating element for research reactors and a based on it heat-generating assembly (versions) The invention is pertaining to the field of nuclear power engineering, in particular, to production of heat-generating elements (further - fuel elements) and the heat-generating assemblies (further - fuel elements assemblies) for research reactors using a low (less than 20 %) enriched nuclear material. The technical result of the invention is enhancement of production capabilities for upgrading the existing research reactors, the fissile regions of which differ in dimensions and forms, using the universal rod-shaped fuel element and the based on it fuel elements assembly. The fuel element is made in the form of a tubular sealed on its end faces by plugs shell made out of an aluminum alloy of 0.30 up to 0.45 mm thick with four distancing screw-type ribs on the outer surface. The diameter of a circumscribed circle of a fuel element cross section makes from 4.0 - 8.0 mm. Each rib protrudes above the shell from 0.4 up to 1,0 mm in height and is placed in the cross section plane at an angle of 90° to the neighboring rib and twisted in spiral with a step from 100 up to 400 mm, predominantly from 300 up to 340 m. Inside the shell there is a fuel core made out of a dispersive composition of uranium-containing particles and an aluminum alloy, in which a volumetric content of uranium-containing particles makes up to 45 %, the uranium-containing particles dimension makes from 63 up to 315 microns, and the shell and the core have a diffusion cohesion among themselves, formed at the fuel elements manufacture by the method of a joint extrusion through a forming array of a composite cylindrical blank consisting of the fuel element core, the plugs and the shell. On the basis of the aforesaid fuel element the versions of the heat-generating assemblies are developed for research reactors of different types with various geometrical forms of the fissile regions. |
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Fuel cell and gas-cooled nuclear reactor using such fuel cells Fuel cell 10 designed for use in gas-cooled nuclear reactor has assembly of two adjacent fuel plates 12a, 12b disposed relative to one another and shaped so that they form channels 14 for gaseous coolant flow. Fuel plates 12a, 12b incorporate elementary fissionable particles, better non-coated ones, implanted in metal matrix. Metal coating may be deposited on both ends of each plate 12a and 12b. |
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Method for manufacturing fuel elements Core for three-layer assembly that has sleeve, circular core, and plugs is provided with longitudinal bonds made of sleeve material and three-layer tube obtained upon joint hot extrusion and drawing is cut along bonds; segments obtained in the process are drawn through slit die. |
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Process line for fuel element manufacture Process line primarily used for manufacturing fuel elements for VVER-1000 and VVER-440 reactors has charged can weighing device built integral with can-and-plug assembly weighing device that determines net weight of charged can by internal components, box holding devices for discharging fuel pellets from rejected fuel element, destructive testing of helium pressure within can, and preparing specimens for metallographic inspection. |
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Method for producing tubular three-layer fuel elements Proposed method includes production of powder mixture, powder mixing in plasticizer environment, cold molding in core billet with plasticizer, thermal sintering, hot molding-calibration of fuel core, core placing in can made in the form of sleeve with annular slot, calibration, hot molding through die, and drawing; inner surface of external can of sleeve is provided with longitudinal bulges and outer surface bears bulge location marks; fuel core is provided with longitudinal flats and placed in sleeve taking care to align bulges of the latter with core flats; in the course of drawing marks are aligned on arbor ribs. |
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Fuel rod for water-moderated water-cooled power reactor Proposed fuel rod designed for use in water-cooled water-moderated power reactors such as type VVER-1000 reactor has fuel core disposed in cylindrical can. Outer diameter of fuel rod is chosen between 7.00 . 10-3 and 8.79 . 10-3m and fuel core diameter is between 5.82 . 10-3 and 7.32 . 10-3m and mass, between 0.93 and 1.52 kg, fuel core to fuel rod length ratio being between 0.9145 and 0.9483. |
Another patent 2513348.