CN110223789B - Method for manufacturing high-uranium-density coated fuel particles, inert-based dispersed fuel pellets, integrated fuel rod and manufacturing method thereof - Google Patents

Method for manufacturing high-uranium-density coated fuel particles, inert-based dispersed fuel pellets, integrated fuel rod and manufacturing method thereof Download PDF

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CN110223789B
CN110223789B CN201910377421.9A CN201910377421A CN110223789B CN 110223789 B CN110223789 B CN 110223789B CN 201910377421 A CN201910377421 A CN 201910377421A CN 110223789 B CN110223789 B CN 110223789B
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uranium
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fuel
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CN110223789A (en
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马赵丹丹
李锐
黄华伟
刘彤
高思宇
张显生
廖业宏
任啟森
张强
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China General Nuclear Power Corp
China Nuclear Power Technology Research Institute Co Ltd
CGN Power Co Ltd
Guangdong Nuclear Power Joint Venture Co Ltd
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China General Nuclear Power Corp
China Nuclear Power Technology Research Institute Co Ltd
CGN Power Co Ltd
Guangdong Nuclear Power Joint Venture Co Ltd
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C21/00—Apparatus or processes specially adapted to the manufacture of reactors or parts thereof
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C21/00—Apparatus or processes specially adapted to the manufacture of reactors or parts thereof
    • G21C21/02—Manufacture of fuel elements or breeder elements contained in non-active casings
    • G21C21/10—Manufacture of fuel elements or breeder elements contained in non-active casings by extrusion, drawing, or stretching by rolling, e.g. "picture frame" technique
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/42—Selection of substances for use as reactor fuel
    • G21C3/58—Solid reactor fuel Pellets made of fissile material
    • G21C3/60—Metallic fuel; Intermetallic dispersions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract

The invention discloses a manufacturing method of high-uranium-density coated fuel particles, an inert-base dispersed fuel pellet, an integrated fuel rod and a manufacturing method of the integrated fuel rod, wherein the manufacturing method of the high-uranium-density coated fuel particles comprises the steps of S1, preparing mixed powder of U-Si compounds by adopting a smelting method; s2, separating the powder of the mixed powder by a centrifugal separation method according to the difference of the density of different powder in the mixed powder; s3, separating U3Si2Mixing the powder with a binder to prepare a spherical core with a smooth surface; and S4, sequentially depositing to form a plurality of coating layers on the surface of the core through a vapor deposition method, and preparing the high-uranium-density coated fuel particles. The method obtains the UxSiy powder with higher purity by matching a smelting method with a powder centrifugal separation method, thereby realizing continuous production; the core coated with the fuel particles is prepared by adopting a powder metallurgy method instead of a sol-gel method, so that the pollution generated by chemical waste liquid is reduced, the operation is simplified, the preparation cost is reduced, and the economy is improved.

Description

Method for manufacturing high-uranium-density coated fuel particles, inert-based dispersed fuel pellets, integrated fuel rod and manufacturing method thereof
Technical Field
The invention relates to the technical field of nuclear fuel, in particular to a manufacturing method of high-uranium-density coated fuel particles, an inert-base dispersion fuel pellet and a manufacturing method thereof, and an integrated fuel rod and a manufacturing method thereof.
Background
The development of high-temperature gas cooled reactors is closely related to the successful development and development of coated fuel particles. The coating fuel particles produced in the industry have a spherical UO2The core is wrapped with 4 layers of closed spherical shells by a vapor deposition technology, and the outer parts of the core are respectively a loose buffer layer, a compact barrier layer, a structural support sealing layer and a compact barrier layer (namely TRISO particles, and if only two layers are provided, the BISO particles). The main function of these layers of material is to confine the fissile material, blocking the release of fission products.
In the last century, carbide microspheres were produced by a chemical method in an oak ridge laboratory, and then oxycarbide microspheres were also successfully produced, so that the tradition that oxide was used as a core for a long time is broken through, carbide and oxygen products are blocked in particles by a coating layer, the high-uranium density core improves the whole uranium loading and thermal conductivity, and a large number of test results show that the carbide core particles have a larger application space, and the carbide and oxycarbide microspheres are used as reference fuel core materials for development of high-temperature gas cooled reactors in the U.S. department of energy.
IMDP pellets (IMDP) are TRISO coated fuel particles Dispersion solidified in a cylindrical SiC Matrix or metal Matrix. The SiC matrix or the metal matrix not only plays a role in structural support, but also has the functions of radiation resistance, corrosion resistance and fission product release shielding. Studies on the preparation of the TRISO-coated fuel particles and the inert-based fuel were successively conducted by a plurality of research institutes in the united states, japan, and korea. The industrial-grade coating fuel particle and graphite spherical fuel element production line is established in China at Qinghua university and China northern nuclear fuel element limited company. To overcome the limitation of volume fraction of fuel in manufacturing, U-Si compound U with high uranium density is used in the United states3Si2The ceramic is dispersed in the base material to form the fuel plate, so that the large deformation caused by irradiation instability can be avoided, and the fuel is successfully applied and dispersed under the condition of certain characteristics.
Currently, research institutes in the united states, korea, etc. have adopted methods for clad fuel core preparation and IMDP/FCM preparation mainly: preparing coating fuel core powder by a smelting method and an atomization method; preparing a fuel core coated with carbide, nitride and oxycarbide by a chemical method, namely a sol-gel method; preparing a four-layer TRISO coating layer by a vapor deposition method, wherein the coating material comprises ZrC, SiC and the like; and preparing an inert base dispersion fuel pellet by hot-pressing sintering, dispersing the cladding fuel core in a ceramic or metal matrix, and integrally preparing the fuel rod. However, the method for preparing UxSiy coated fuel particles is not available at home and abroad. The search for processes for the preparation of IMDP pellets of UxSiy coated fuel particles and UxSiy core is one of the important research directions for coated fuels.
The traditional coating fuel particle adopts UO2As a core, however UO2The thermal conductivity is low, and the thermal conductivity is also reduced remarkably under the high-temperature and irradiation environment. According to the state of the art, the volume fraction of TRISO particles in IMDP fuels does not exceed 40% at the most and is due to TRSIO itselfThe structural feature of body, only about one eighth volume is the uranium dioxide fuel in the whole granule, and consequently the holistic uranium charge of fuel pellet is very low, and the economic nature is very poor, is difficult to satisfy the operation requirement of present commercial pressurized water reactor. The improvement of TRISO uranium loading and the expansion of application become research hotspots in various countries.
The preparation process of the UxSiy coated fuel particle comprises three parts: preparation of UxSiy powder, preparation of a TRISO core and preparation of a coating layer. The preparation of UxSiy powder usually adopts a smelting method and an atomization method. The smelting method has low production cost and good ingot casting uniformity, is easy to realize large-scale production, but the ingot casting is easy to generate a large amount of impurities, and is not easy to separate and purify powder. The powder prepared by the atomization method has good fluidity, and the fuel element prepared by the powder has high thermal conductivity, but the atomization method is not easy to realize large-scale production.
The common chemical method for preparing the TRISO core is a sol-gel method, the chemical method is suitable for preparing the core of the coated particles such as oxide, carbide and nitride, the process is mature, and the sphericity of the core of the coated particles is good. For the preparation of the UxSiy core, it is not easy to find a suitable molten precursor solution, so that a chemical method cannot be used to prepare the UxSiy fuel core. In addition, the chemical method is not easy to produce in large scale, has high cost and has little waste liquid pollution.
Disclosure of Invention
The invention aims to provide a method for manufacturing high-uranium-density coated fuel particles with high uranium density and high thermal conductivity, an inert-base dispersion fuel pellet made of the high-uranium-density coated fuel particles and a manufacturing method thereof, an integrated fuel rod made of the high-uranium-density coated fuel particles and a manufacturing method thereof.
The technical scheme adopted by the invention for solving the technical problems is as follows: provided is a method for manufacturing high-uranium-density coated fuel particles, which comprises the following steps:
s1, preparing mixed powder of the U-Si compound by a smelting method;
s2, separating the powder of the mixed powder by a centrifugal separation method according to the difference of the density of different powder in the mixed powder;
s3, dividing intoLeaving U3Si2Mixing the powder with a binder to prepare a spherical core with a smooth surface;
and S4, sequentially depositing to form a plurality of coating layers on the surface of the core through a vapor deposition method, and preparing the high-uranium-density coated fuel particles.
Preferably, in step S1, the particle size of the mixed powder is controlled to be 40 μm to 80 μm.
Preferably, step S1 includes:
s1.1, placing the U-Si compound in a vacuum melting furnace, reducing the vacuum degree to be below 20MPa, transmitting power, and heating the temperature according to the melting condition in the furnace until the U-Si compound is completely melted;
s1.2, continuously mechanically stirring until the temperature is 1500-1800 ℃, stopping stirring, stopping power transmission at 1680-1750 ℃, and cooling along with the furnace to obtain a U-Si compound ingot;
s1.3, primarily calcining the U-Si compound ingot, crushing and grinding to obtain mixed powder.
Preferably, according to the centrifugal force F ═ m ω r2Separating the powders with different densities in the mixed powder at different centrifugal rates; where m is the effective mass of the particles, ω is the angular velocity of rotation of the centrifugal rotor, and r is the centrifugal radius.
Preferably, the mixed powder comprises U3Si powder, U3Si2Powder and U3Si5Powder; step S2 includes:
s2.1, pouring the mixed powder into a disc-shaped rotating disc, wherein the disc-shaped rotating disc rotates at a first rotating speed omega1Rotating to make U with maximum density in the mixed powder3Throwing the Si powder into a first collector;
s2.2, treat U3After the Si powder is completely thrown out, the rotating speed of the disc-shaped turntable is reduced, and the rest powder with different densities is layered in the disc-shaped turntable;
s2.3, increasing the rotating speed of the disc-shaped rotating disc to a second rotating speed omega2The higher density U in the residual powder3Si2Throwing the powder into a second collector;
s2.4, treat U3Si2Reducing the rotating speed of the disc-shaped turntable after the powder is completely thrown out;
s2.5, increasing the rotating speed of the disc-shaped rotating disc to a third rotating speed omega3U in the remaining powder3Si5The powder is thrown out into a third collector.
Preferably, the diameter of the core is 500 μm to 800 μm.
Preferably, step S3 includes:
s3.1, separating U3Si2Mixing the powder with a binder, extruding and cutting into short cylinders;
s3.2, pre-burning the short column body to enable the density of the short column body to be 65-80% T.D.;
s3.3, placing the pre-sintered short column body in a ball mill for grinding to form a sphere with a smooth surface;
and S3.4, sintering the sphere in a reducing atmosphere to form a spherical core.
Preferably, in step S4, the coating layer has four layers, which are a loose buffer layer, a dense barrier layer, a structural support sealing layer and a lubrication protection layer from inside to outside.
The invention also provides an inert matrix dispersion fuel pellet which is prepared by adopting the high-uranium-density coated fuel particles prepared by any one of the preparation methods.
The invention also provides a manufacturing method of the inert matrix dispersion fuel pellet, which comprises the following steps:
s1, uniformly mixing 5-20wt.% of inert matrix powder with a solvent to form slurry, spraying the slurry on the surfaces of rolling high-uranium-density coated fuel particles, and drying the slurry to form powder coating layers adhered to the surfaces of the high-uranium-density coated fuel particles;
s2, mixing the rest inert matrix powder and the high-uranium-density coated fuel particles with the powder coating layer in proportion, and putting the mixture into a pellet mould to be pressed into a blank;
and S3, carrying out vacuum pressureless sintering densification on the blank to obtain the inert base dispersion fuel pellet.
Preferably, in step S2, the pressing process includes:
applying pressure of 8-16MPa for prepressing, and then sealing by oiled paper in vacuum;
and applying 100-300MPa of equal-pressure load to the blank body subjected to the vacuum sealing of the oiled paper by using a cold isostatic press, and maintaining the pressure for 1-5 minutes to enable the initial density of the blank body to reach more than 50%.
Preferably, in step S3, the vacuum pressureless sintering densification comprises:
heating to 500-600 ℃ at a heating rate of 5-20 ℃/min/min;
the voltage is applied to 80-150V, the pulse current is 3000A-5000A, the densification is rapidly realized in the second-level process, and the density reaches 92% -98%.
The invention also provides an integrated fuel rod which is characterized by being prepared from the high-uranium-density coated fuel particles prepared by the preparation method.
The invention also provides a manufacturing method of the integrated fuel rod, which comprises the following steps:
s1, uniformly mixing the high-uranium-density coated fuel particles with FeCrAl powder, and then loading the mixture in a FeCrAl cladding in a dispersing way;
s2, heating the eddy current generated by the induction coil to 1300-1500 ℃ to melt FeCrAl powder into liquid FeCrAl, and immersing all high-uranium-density coated fuel particles;
and S3, cooling and solidifying the liquid FeCrAl to form a FeCrAl matrix and fixedly connecting the FeCrAl matrix with the FeCrAl cladding, and solidifying the high-uranium-density cladding fuel particles in the FeCrAl matrix in a dispersed form to prepare the integrated fuel rod.
In the method for manufacturing the high-uranium-density coated fuel particles, the core is made of UxSiy(U3Si2) Prepared from raw materials, compared with UO2The uranium-enriched fuel has high uranium density and high thermal conductivity, can improve the uranium density of a core material by more than 17 percent, and obviously improves the uranium loading of the fuel under the condition of not increasing the enrichment degree. Firstly, preparing U by adopting a smelting methodxSiyPulverizing, and centrifuging to separate different UxSiySeparating the powder to obtain single powder with higher purity, and realizing continuous production;the dry method, namely the powder metallurgy method is adopted to replace the sol-gel method to prepare the core coated with the fuel particles, so that the pollution generated by chemical waste liquid is reduced, the operation is simplified, the preparation cost is reduced, and the economy is improved.
In addition, the invention also uniformly disperses the coating fuel particles in the inert matrix material by a flash combustion method and sinters the coating fuel particles into nuclear fuel pellets or integrated fuel rods with a composite structure, and the nuclear fuel pellets or the integrated fuel rods can be used for accident fault-tolerant fuels, large-scale advanced pressurized water reactors and fuel systems of other advanced nuclear energy systems.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
fig. 1 is a schematic cross-sectional view of a high-uranium-density coated fuel particle produced by the method of the present invention;
FIG. 2 is a schematic diagram of the structure of an inert matrix dispersed fuel pellet according to one embodiment of the invention.
Detailed Description
The manufacturing method of the high-uranium-density coated fuel particle can comprise the following steps:
s1, preparing the mixed powder of the U-Si compound by adopting a smelting method.
From the binary phase diagram of U-Si, the U-Si compound (U)xSiyX-3, y-1-5) stable compounds are U3Si、U3Si2And U3Si5. The U-Si powder obtained at normal temperature may be a single compound or a plurality of compounds may coexist.
This step uses a U-Si compound (solid state) as a starting material to produce a mixed powder containing multiple allotropes.
Specifically, the step S1 may include:
s1.1, placing the U-Si compound in a vacuum smelting furnace, reducing the vacuum to be below 20MPa, transmitting power, and heating the temperature according to the melting condition in the furnace until the U-Si compound is completely melted.
And S1.2, continuously mechanically stirring after the U-Si compound is completely melted, stopping stirring when the temperature is 1500-1800 ℃, stopping power transmission when the temperature is 1680-1750 ℃, and cooling along with the furnace to obtain the U-Si compound ingot.
S1.3, primarily calcining the cast U-Si compound ingot, crushing and grinding by using a grinder to obtain mixed powder.
The particle size of the mixed powder is controlled to be 40-80 μm.
The stable compound powder is prepared by the smelting method, so that the industrial scale production of raw materials is realized, impurities or insufficient purity caused by the separation of the powder at high temperature is avoided, the process is simplified, and the mass production of fuel cores is facilitated.
The mixed powder may include U3Si powder, U3Si2Powder and U3Si5And (3) powder. The various U-Si compounds and their characteristics are shown in Table 1 below.
TABLE 1
Figure GDA0002525797660000071
Figure GDA0002525797660000081
As can be seen from the above table, all three U-Si compounds have excellent uranium density, where U is3Si has the highest density and is sequentially U3Si2、U3Si5。
And S2, separating the powder of the mixed powder by a centrifugal separation method according to the density difference among different powders in the mixed powder.
This step is used to mix U in the powder3Si powder, U3Si2Powder and U3Si5Separating the powder to obtain various compound powders with higher purity.
Specifically, according to the centrifugal force F ═ m ω r2Separating the powder with different densities in the mixed powder at different centrifugal rates; where m is the effective mass of the particles, ω is the angular velocity of rotation of the centrifugal rotor, and r is the centrifugal radius.
The step S2 may specifically include the following steps:
s2.1, pouring the mixed powder into a disc-shaped rotating disc, wherein the disc-shaped rotating disc rotates at a first rotating speed omega1Rotating to make U with maximum density in the mixed powder3The Si powder is thrown out into the first collector.
S2.2, treat U3After the Si powder is completely thrown out, the rotating speed of the disc-shaped turntable is reduced, and the rest powder with different densities is layered in the disc-shaped turntable.
The first collector collects the U3After the Si powder, the second collector was replaced to collect other powders with lower density.
S2.3, increasing the rotating speed of the disc-shaped rotating disc to a second rotating speed omega2The higher density U in the residual powder3Si2The powder is thrown out into a second collector.
S2.4, treat U3Si2The rotation speed of the disc-shaped turntable is reduced after the powder is completely thrown out.
The second collector is replaced by a third collector to collect further powder which is subsequently thrown out.
S2.5, increasing the rotating speed of the disc-shaped rotating disc to a third rotating speed omega3U in the remaining powder3Si5Thrown out into the third collector.
The first rotational speed ω1Second rotation speed omega2And a third rotational speed ω3The specific numerical value or range value of (a) is set according to the centrifugal radius, the powder particle size, the height of the turntable, and the like.
In order to ensure the purity of each powder, the corresponding rotating speed of the powder can be repeated, and other rotating speeds are converted after the corresponding powder is completely separated.
The powder is separated by a centrifugal separation method, allotropes with different densities are separated, and the method has the following advantages: the method can continuously produce powder, easily realize the industrial scale of raw materials, and has simple operation and convenient control; impurities generated during U-Si powder separation are avoided, and the powder purity can be ensured; is beneficial to the mass production of the coated fuel particles with the U-Si core.
S3, separating U3Si2Mixing the powder with a binder to obtainA spherical core with smooth surface.
The diameter of the core is 500-800 μm.
U separated in the above step S23Si powder and U3Si5The powder can be continuously smelted and separated to obtain U3Si2And (3) powder.
Step S3 specifically includes the following steps:
s3.1, separating U3Si2The powder is mixed with a binder, extruded through fine holes and cut into short cylinders.
All the cut short cylinders have the same or approximately the same volume, so that the balls with the same volume can be ground later.
S3.2, pre-burning the short column body to enable the density of the short column body to be 65-80% T.D.
The presintering adopts an atmosphere furnace, and the presintering temperature is lower than the subsequent sintering temperature.
And S3.3, placing the pre-sintered short column body into a ball mill for grinding to form a ball body with a smooth surface.
The specific operation is as follows: placing the short column body in the groove of the lower turntable, and exposing the groove at the top; the upper rotary table is matched with the lower rotary table, grinding oil is injected between the upper rotary table and the lower rotary table, and the short column body is immersed in a viscous mixture of diamond powder; the upper turntable and the lower turntable rotate at the same time at a certain rotating speed and rotate in opposite directions, so that the short cylinder continuously rolls in the groove, the short cylinder continuously contacts and rubs with the groove wall of the groove and the upper turntable, and the diamond powder continuously grinds corners of the short cylinder to finally form a sphere with a certain size, sphericity and smooth surface.
In order to obtain the sphere with the required size, the pressure, the rotating speed and the ball milling time between the upper turntable and the lower turntable can be adjusted, the pre-sintering density is controlled, and the like.
And S3.4, sintering the sphere in a reducing atmosphere to form a spherical core.
And (3) adopting corresponding sintering temperatures according to different melting points of the U-Si compounds, wherein the sintering temperatures are slightly lower than the corresponding melting points.
And S4, sequentially depositing to form a plurality of coating layers on the surface of the core by a vapor deposition method to prepare the high-uranium-density coated fuel particles.
In this embodiment, the coating layer has four layers, and from inside to outside is loose buffer layer, compact barrier layer, structural support sealing layer and lubricated protective layer in proper order.
The parameters of the cores and the respective cladding layers are shown in table 2 below.
TABLE 2
Figure GDA0002525797660000101
As shown in fig. 1, the high-uranium-density coated fuel particle manufactured by the manufacturing method of the present invention includes a core 10, a loose buffer layer 11 sequentially coated outside the core 10, a dense barrier layer 12, a structural support sealing layer 13, and a lubrication protective layer 14.
The method for producing the high uranium density coated fuel particle according to the present invention will be described below with reference to specific examples.
Example 1
Obtaining high purity U by powder separation3Si2And (3) powder.
Weighing a certain amount of U3Si2The powder is mixed with 2-5 wt.% binder to form a viscous mass. The dope is extruded from the fine holes by a fine hole extrusion die to form short cylinders with the length of 700 +/-50 nm. And (3) presintering the short column body by using a sintering furnace, wherein the presintering temperature is 400-600 ℃, the short column body is cooled along with the furnace after heat preservation for 3-5h, the density of the presintering short column body is 80 percent T.D., and the shrinkage of the size of a small ball is not obvious due to the lower presintering temperature. And (3) placing the pre-sintered short column body in a ball mill, rotating a lower turntable, and grinding at the rotating speed of 50r/min for 10-12 hours to form a small ball. And taking out the ground pellets, cleaning and screening the ground pellets, and screening out the pellets with the size of 600 +/-50 nm. Sieving out qualified pellets for sintering, and introducing H in an atmosphere sintering furnace2The sintering temperature is 1300-1500 ℃, the diameter of the sintered pellets is about 500 +/-50 nm, and the pellets with unqualified sizes are screened.
4 layers of closed spherical shells are wrapped outside the small sphere in a vapor deposition mode, namely a loose buffer layer, a compact barrier layer, a structural support sealing layer and a lubricating protective layer are respectively formed, so that the coated fuel particles are formed, and the parameters of the coating layer are shown in the following table 3.
TABLE 3
Figure GDA0002525797660000111
Example 2
Obtaining high purity U by powder separation3Si2And (3) powder.
Weighing a certain amount of U3Si2The powder is mixed with 2-5 wt.% binder to form a viscous mass. The dope is extruded from the pores by a pore extrusion die to form short columns with the length of 600-700 nm. And (3) pre-burning the short column body by using a sintering furnace, wherein the pre-burning temperature is 500 +/-50 ℃, the temperature is kept for 2-5h, then the temperature is reduced along with the furnace, the density of the pre-burned short column body is 80 percent T.D., and the shrinkage of the size of a small ball is not obvious due to the lower pre-burning temperature. And (3) placing the pre-sintered short column body in a ball mill, rotating a lower turntable, and grinding at the rotating speed of 50 +/-10 r/min for 8-16 hours to form a small ball. And taking out the ground pellets, cleaning and screening the ground pellets, and screening out the pellets with the size of 600 +/-50 nm. Sieving out qualified pellets for sintering, and introducing H in an atmosphere sintering furnace2The sintering temperature is 1300-1500 ℃, the diameter of the sintered pellets is about 500 +/-50 nm, and the pellets with unqualified sizes are screened.
4 layers of closed spherical shells are wrapped outside the small sphere in a vapor deposition mode, namely a loose buffer layer, a compact barrier layer, a structural support sealing layer and a lubricating protective layer are respectively formed, so that the coated fuel particles are formed, and the parameters of the coating layer can be referred to the parameters shown in the table 3.
The inert-based dispersion fuel pellet of one embodiment of the invention is prepared by adopting the prepared high-uranium-density coated fuel particles. As shown in fig. 2, in an inert matrix dispersed fuel pellet, high uranium density cladding fuel particles 1 are dispersed in an inert matrix 2.
The method for manufacturing the inert-based dispersed fuel pellet of the invention can comprise the following steps:
s1, uniformly mixing 5-20wt.% of inert matrix powder with a solvent (such as ethanol) to form slurry, spraying the slurry on the surfaces of rolling high-uranium-density coated fuel particles, and drying the slurry to form powder coating layers adhered on the surfaces of the high-uranium-density coated fuel particles.
The drying mode can adopt a hot air blowing mode to volatilize the solvent in the slurry.
And S2, mixing the rest inert matrix powder and the high-uranium-density coated fuel particles with the powder coating according to a proportion, and putting the mixture into a pellet mould to be pressed into a blank.
During pressing, firstly applying pressure of 8-16MPa for prepressing, and then sealing by using oiled paper in vacuum; and applying 100-300MPa of equal-pressure load to the blank body subjected to the vacuum sealing of the oiled paper by using a cold isostatic press, and maintaining the pressure for 1-5 minutes to enable the initial density of the blank body to reach more than 50%.
And S3, carrying out vacuum pressureless sintering densification on the blank to obtain the inert base dispersion fuel pellet.
Wherein the vacuum pressureless sintering densification comprises:
heating to 500-800 ℃ at a heating rate of 5-20 ℃/min; the rate of temperature rise may preferably be 10 ℃/min.
The voltage is applied to 80-150V, the pulse current is applied to 3000A-5000A, the inert matrix dispersion fuel pellet is rapidly densified in the second-level process, and the density reaches more than 92% (92% -98%).
The integrated fuel rod of the embodiment of the invention is prepared by adopting the prepared high-uranium-density coated fuel particles. In the integrated fuel rod, high-uranium-density coated fuel particles are dispersed in a FeCrAl matrix, and the FeCrAl matrix is positioned in a FeCrAl cladding and integrally connected with the inner wall of the FeCrAl cladding.
The manufacturing method of the integrated fuel rod of the invention can comprise the following steps:
and S1, uniformly mixing the high-uranium-density coated fuel particles with FeCrAl powder, and then dispersedly loading the mixture in a FeCrAl cladding.
S2, heating the eddy current generated by the induction coil to 1300-1500 ℃ to melt FeCrAl powder and submerge all the high-uranium-density coated fuel particles.
The molten liquid FeCrAl is physically connected with the inner wall of the FeCrAl jacket. And (3) forcibly cooling the outer wall of the FeCrAl jacket while heating and melting the FeCrAl powder, and controlling the highest temperature of the FeCrAl jacket so as to prevent the FeCrAl powder from being annealed due to property change caused by eddy current heating.
S3, cooling and solidifying the liquid FeCrAl to form a FeCrAl matrix and fixedly connecting the FeCrAl matrix with the FeCrAl cladding, and solidifying the high-uranium-density cladding fuel particles in the FeCrAl matrix in a dispersed form to prepare the integrated fuel rod.
In the inert matrix dispersion fuel pellet and the integrated fuel rod, the inert matrix and the cladding can be dissolved in nitric acid, so that the recovery of the cladding fuel particles and the fuel circulation are realized.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (12)

1. A method for manufacturing high uranium density coated fuel particles is characterized by comprising the following steps:
s1, preparing mixed powder of the U-Si compound by a smelting method; the mixed powder comprises U3Si powder, U3Si2Powder and U3Si5Powder;
s2, separating the powder of the mixed powder by a centrifugal separation method according to the difference of the density of different powder in the mixed powder; step S2 includes:
s2.1, pouring the mixed powder into a disc-shaped rotating disc, wherein the disc-shaped rotating disc rotates at a first rotating speed omega1Rotating to make U with maximum density in the mixed powder3Throwing the Si powder into a first collector;
s2.2, treat U3After the Si powder is completely thrown out, the rotating speed of the disc-shaped turntable is reduced, and the rest powder with different densities is layered in the disc-shaped turntable;
s2.3, increasing the rotating speed of the disc-shaped rotating disc to a second rotating speed omega2The higher density U in the residual powder3Si2Throwing the powder into a second collector;
s2.4, treat U3Si2Reducing the rotating speed of the disc-shaped turntable after the powder is completely thrown out;
s2.5, increasing the rotating speed of the disc-shaped rotating disc to a third rotating speed omega3U in the remaining powder3Si5Throwing the powder into a third collector;
s3, separating U3Si2Mixing the powder with a binder to prepare a spherical core with a smooth surface;
step S3 includes:
s3.1, separating U3Si2Mixing the powder with a binder, extruding and cutting into short cylinders;
s3.2, pre-burning the short column body to enable the density of the short column body to be 65-80% T.D.;
s3.3, placing the pre-sintered short column body in a ball mill for grinding to form a sphere with a smooth surface;
s3.4, sintering the sphere in a reducing atmosphere to form a spherical core;
and S4, sequentially depositing to form a plurality of coating layers on the surface of the core through a vapor deposition method, and preparing the high-uranium-density coated fuel particles.
2. The method for producing high-uranium-density coated fuel particles according to claim 1, wherein in step S1, the particle size of the mixed powder is controlled to be 40 μm to 80 μm.
3. The method for manufacturing high uranium density coated fuel particles according to claim 1, wherein step S1 includes:
s1.1, placing the U-Si compound in a vacuum smelting furnace, reducing the vacuum to be below 20MPa, transmitting power, and heating the temperature according to the melting condition in the furnace until the U-Si compound is completely melted;
s1.2, continuously mechanically stirring until the temperature is 1500-1800 ℃, stopping stirring, stopping power transmission at 1680-1750 ℃, and cooling along with the furnace to obtain a U-Si compound ingot;
s1.3, primarily calcining the U-Si compound ingot, crushing and grinding to obtain mixed powder.
4. A method of manufacturing high uranium density coated fuel particles according to claim 1, wherein F = m ω r is a centrifugal force2Separating the powders with different densities in the mixed powder at different centrifugal rates; where m is the effective mass of the particles, ω is the angular velocity of rotation of the centrifugal rotor, and r is the centrifugal radius.
5. A method of manufacturing high uranium density coated fuel particles according to claim 1, wherein the diameter of the core is 500 μ ι η -800 μ ι η.
6. The method of claim 1, wherein in step S4, the coating layer has four layers, namely, a loose buffer layer, a dense barrier layer, a structural support sealing layer and a lubrication protective layer from the inside to the outside.
7. An inert-based dispersed fuel pellet produced by using the high uranium density coated fuel particle produced by the production method according to any one of claims 1 to 6.
8. A method of manufacturing inert-based dispersed fuel pellets according to claim 7, comprising the steps of:
s1, uniformly mixing 5-20wt.% of inert matrix powder with a solvent to form slurry, spraying the slurry on the surfaces of rolling high-uranium-density coated fuel particles, and drying the slurry to form powder coating layers adhered to the surfaces of the high-uranium-density coated fuel particles;
s2, mixing the rest inert matrix powder and the high-uranium-density coated fuel particles with the powder coating layer in proportion, and putting the mixture into a pellet mould to be pressed into a blank;
and S3, carrying out vacuum pressureless sintering densification on the blank to obtain the inert base dispersion fuel pellet.
9. The method of manufacturing inert-based dispersed fuel pellets according to claim 8, wherein in step S2, the pressing process includes:
applying pressure of 8-16MPa for prepressing, and then sealing by oiled paper in vacuum;
and applying 100-300MPa of equal-pressure load to the blank body subjected to the vacuum sealing of the oiled paper by using a cold isostatic press, and maintaining the pressure for 1-5 minutes to enable the initial density of the blank body to reach more than 50%.
10. The method of manufacturing inert-based dispersed fuel pellets according to claim 8, wherein the vacuum pressureless sintering densification in step S3 comprises:
heating to 500-600 ℃ at a heating rate of 5-20 ℃/min;
the voltage is applied to 80-150V, the pulse current is 3000A-5000A, the densification is rapidly realized in the second-level process, and the density reaches 92% -98%.
11. An integrated fuel rod, characterized by being made of the high uranium density coated fuel particles produced by the production method according to any one of claims 1 to 6.
12. A method of manufacturing an integrated fuel rod of claim 11, comprising the steps of:
s1, uniformly mixing the high-uranium-density coated fuel particles with FeCrAl powder, and then loading the mixture in a FeCrAl cladding in a dispersing way;
s2, heating the eddy current generated by the induction coil to 1300-1500 ℃ to melt FeCrAl powder into liquid FeCrAl, and immersing all high-uranium-density coated fuel particles;
and S3, cooling and solidifying the liquid FeCrAl to form a FeCrAl matrix and fixedly connecting the FeCrAl matrix with the FeCrAl cladding, and solidifying the high-uranium-density cladding fuel particles in the FeCrAl matrix in a dispersed form to prepare the integrated fuel rod.
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Families Citing this family (10)

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Publication number Priority date Publication date Assignee Title
CN110993134B (en) * 2019-11-12 2023-01-06 中国工程物理研究院材料研究所 U-shaped connector 3 Si 2 Preparation method of alloy fuel
CN110853769A (en) * 2019-11-21 2020-02-28 中国核动力研究设计院 Pellet fuel core, fuel rod and small-size reactor of metal cooling
CN113012834A (en) * 2019-12-20 2021-06-22 中核北方核燃料元件有限公司 Preparation method of uranium nitride composite uranium trisilicon two-fuel pellet
CN111195606B (en) * 2019-12-26 2021-11-09 岭东核电有限公司 Method for separating triuranium silicon in uranium silicide smelting body and nuclear fuel pellet
CN111508628B (en) * 2020-04-17 2022-05-13 中国科学院合肥物质科学研究院 Preparation method of tungsten or molybdenum-based fuel pellet with uranium dioxide core balls dispersed and distributed
CN112242203B (en) * 2020-10-19 2022-04-22 中国核动力研究设计院 Component grid arrangement form for loading FCM fuel
CN112678872A (en) * 2020-11-20 2021-04-20 中核北方核燃料元件有限公司 Method for recycling uranium in spherical fuel element
CN112992390A (en) * 2021-02-25 2021-06-18 上海核工程研究设计院有限公司 High-safety uranium silicide composite fuel pellet
CN113816749B (en) * 2021-10-21 2023-02-17 中国科学院上海应用物理研究所 High-density U 3 Si 2 Method for producing fuel
EP4293686A4 (en) * 2022-01-07 2024-05-01 Ling Ao Nuclear Power Co., Ltd. High-uranium-density atf nuclear fuel pellet and preparation method therefor

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006234405A (en) * 2005-02-22 2006-09-07 Nuclear Fuel Ind Ltd Clad fuel particle, overcoat particles and method of manufacturing same
US9171646B2 (en) * 2007-10-04 2015-10-27 Lawrence Livermore National Security, Llc Control of a laser inertial confinement fusion-fission power plant
US10522255B2 (en) * 2015-02-19 2019-12-31 X-Energy, Llc Nuclear fuel pebble and method of manufacturing the same
US10109381B2 (en) * 2015-06-22 2018-10-23 Battelle Energy Alliance, Llc Methods of forming triuranium disilicide structures, and related fuel rods for light water reactors
CN106981318B (en) * 2017-04-13 2019-03-08 中国工程物理研究院材料研究所 A kind of inertia base disperse pellet fuel and its preparation method and application
CN107093468B (en) * 2017-05-27 2020-05-05 中国工程物理研究院材料研究所 ZrC inert-based dispersion pellet nuclear fuel and preparation method and application thereof
CN107180654B (en) * 2017-05-27 2020-05-01 中国工程物理研究院材料研究所 MAX phase ceramic matrix dispersion pellet nuclear fuel and preparation method and application thereof
CN108335760B (en) * 2018-02-01 2020-08-11 中国工程物理研究院材料研究所 Preparation method of high-uranium-loading-capacity dispersed fuel pellet
CN109326363B (en) * 2018-09-29 2020-12-29 中广核研究院有限公司 Dispersed fuel pellet, preparation method thereof and fuel rod
CN109461509B (en) * 2018-09-29 2020-11-10 中广核研究院有限公司 Inert matrix dispersion fuel pellet and preparation method thereof
CN109594017A (en) * 2018-11-27 2019-04-09 中国科学院金属研究所 A kind of preparation method of oxide dispersion intensifying FeCrAl alloy pipe

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