30 results about "Uranium nitride" patented technology

The invention relates to a preparation method of uranium nitride fuel powder and a pellet, which comprises the following steps: (1) carrying out surface cleaning treatment on a pure metal uranium lump; (2) hydrogenating the pure metal uranium lump in hydrogen at 150-300 DEG C for 2-16 hours, dehydrogenating in a vacuum, and repeating the hydrogenation-dehydrogenation several times to obtain metal uranium powder; (3) nitridizing the metal uranium powder in nitrogen at 200-600 DEG C for 6-24 hours to obtain U2N3 powder; (4) denitrifying the U2N3 powder in a mold, keeping the system vacuum, pressurizing the mold to 30-60 MPa, sintering at 1450-1620 DEG C for 1-2 hours, and cooling to obtain the UN ceramic pellet. The method provided by the invention is simple in technique and easy to control; and the obtained intermediate product U2N3 powder has higher purity and higher sintering activity, and can be finally subjected to hot pressed sintering to obtain the UN fuel pellet of which the TD is up to 98.9%.

The invention discloses a uranium carbide pellet, a preparation method thereof and a fuel rod. The preparation method of uranium carbide pellets comprises the following steps: S1, weighing uranium nitride powder and a carbon source according to a molar ratio of 1:0.8-1.5 and adding them to a solvent, and mixing them uniformly to form a slurry; S2, mixing the Drying the slurry to obtain a mixed powder; S3, pressing the mixed powder into a green body with a density of 50% or more; S4, high-temperature pressureless sintering to obtain a uranium carbide pellet with a density ≥ 95%. In the present invention, uranium nitride and carbon source are used as raw materials to realize two processes of carbothermal reduction reaction and densification sintering under high-temperature pressureless sintering, without using hot-press sintering process with low production efficiency, and without introducing sintering aids. It avoids the problem of lowering the melting point of pellets, can realize batch sintering, has low energy consumption, and is suitable for industrial production of fuel pellets.

The invention belongs to the field of nuclear fuel preparation and provides a low-temperature synthesis method for uranium nitride powder for solving the problems that an existing uranium nitride powder synthesis technology is over-high in reaction temperature, high in product impurity content or complicated in technological process. The synthesis method comprises the following steps: (1) enabling metallic uranium to fully react with hydrogen to generate uranium hydride powder, increasing the temperature and lastingly vacuumizing to dehydrogenize and convert the uranium hydride powder into metallic uranium powder, and repeating for multiple times; and (2) carrying out quantitative reaction on the metallic uranium powder and nitrogen at a high temperature to prepare the uranium nitride powder. The low-temperature synthesis method for the uranium nitride powder has the advantages of short technological process and low synthesis temperature; the production energy consumption can be significantly reduced; the synthesized uranium nitride powder is small in particle size, low in impurity content and beneficial to improvement of the sintering activity of the uranium nitride powder.

The invention provides a fluidized bed device for preparing uranium nitride, including a gas system, a material mixing system, a low temperature fluidized bed, a high temperature fluidized bed, a tail gas treatment device and an absorption tower; the gas system is connected to a low temperature fluidized bed. The fluidized bed and the high temperature fluidized bed are respectively connected, the mixing system is connected with the low temperature fluidized bed, the low temperature fluidized bed is connected with the high temperature fluidized bed, and the low temperature fluidized bed and the high temperature fluidized bed are respectively connected with the tail gas treatment The device is connected, and the tail gas treatment device is connected with the absorption tower. The present invention also provides a method for using the fluidized bed device for preparing uranium nitride. By controlling the reaction steps to be carried out in the low temperature fluidized bed and the high temperature fluidized bed respectively, the invention ensures the smooth progress of the reaction under different temperature requirements; the tail gas is purified in the tail gas treatment device to ensure that the discharged gas is harmful to the environment No pollution. The invention can ensure high reaction yield of uranium nitride preparation and complete exhaust gas disposal.

Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

The invention discloses a method and a device for preparing a uranium surface anti-corrosion protecting layer through atmospheric laser passivation and aims to solve the problems that workpiece sizes are limited, demands of industrial production and application are hardly met and prepared uranium nitride films are still corroded to a certain degree in terms of current uranium nitride film preparation by laser nitridation. In the atmospheric environment, the workpiece surface is scanned through nanosecond pulse laser, the laser energy density is 20-70J / cm2, the overlapping ratio is 80%-95%, and therefore a uranium nitrogen oxygen passive film in a ceramic state is prepared on the workpiece surface. A vacuum environment and a special gas source are not required; machining demands of plane workpieces, abnormal-shaped workpieces and large workpieces can be met; the machining speed is high; the demands of the industrial application can be met. Meanwhile, the prepared uranium nitrogen oxygen passive film is excellent in corrosion resistance, pre-treatment of the workpiece surface is not needed; the quantity of generated wastes is small; environment-friendly effect is achieved. By means of the method and the device for preparing the uranium surface anti-corrosion protecting layer through atmospheric laser passivation, during workpiece machining, burrs of the workpiece surface can be removed, and the method and the device have good application prospects.

The invention discloses an integrated uranium nitride thermoelectric conversion device, which includes a casing and a thermoelectric conversion device installed on the casing and having a self-heating function; the thermoelectric conversion device includes a conversion module; the conversion module includes a first conductive sheet, The N-type semiconductor, the P-type semiconductor and two second conductive sheets respectively connected to the N-type semiconductor and the P-type semiconductor; the N-type semiconductor and the P-type semiconductor have the same structure and are divided into a high fission concentration area and a low fission concentration area. The present invention selects uranium nitride as the heat source and thermoelectric conversion material at the same time, reduces the volume and weight of the conversion module, and improves the energy efficiency of the entire thermoelectric conversion device; Timely and stable release of heat energy is an ideal heat source in thermoelectric conversion devices; the integration of thermoelectric material transduction components and radioactive heat sources can effectively avoid radiation damage of thermoelectric materials and prolong the service life of thermoelectric devices.

The invention belongs to the technical field of nuclear fuel preparation, and relates to a microwave synthesis method for zirconium uranium carbonitride powder. The microwave synthesis method sequentially comprises the following steps: (1) ball-milling: weighing UO2 powder, ZrO2 powder and carbon powder, performing uniform mixing, pouring the obtained mixture into a mill pot, adding grinding balls, and performing ball milling; (2) pressing: pouring out the ball-milled material, separating the balls and the material, sieving the material, and pressing the ball-milled raw material powder in a hydraulic machine to form a green body; and (3) performing microwave calcination: placing the green body in a microwave high-temperature furnace, vacuumizing the furnace, introducing an atmosphere gas,carrying out microwave heating to 1300-1600 DEG C, and performing heat insulation calcining to obtain the zirconium uranium carbonitride powder. The synthesis method for zirconium uranium carbonitridepowder is used to directly obtain a (U,Zr)(C,N) single solid solution phase at a low reaction temperature, and the synthesized (U,Zr)(C,N) powder has a high activity, and can be directly used in thesubsequent pellet sintering process.

The invention relates to the technical field of preparation of nuclear fuel pellets, and particularly discloses to a method for preparing a uranium nitride pellet. The method comprises the following steps: 1, preparing a hydrogenation-dehydrogenation sample; 2, performing hydrogenation-dehydrogenation to prepare uranium powder; 3, preparing uranium sesquinitride powder; 4, molding a uranium sesquinitride green body; step 5, sintering the green body to form the uranium nitride pellet. The uranium nitride pellet obtained by the method has good surface appearance, and the density and the chemicalcomposition of the pellet meet the requirements of technical indexes, so the pellet can be used in a novel nuclear reactor to improve the core power density and reduce the release of fission products.