CN113724906A - Semi-continuous structure reinforced uranium dioxide core block and preparation method and application thereof - Google Patents
Semi-continuous structure reinforced uranium dioxide core block and preparation method and application thereof Download PDFInfo
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- CN113724906A CN113724906A CN202111030242.1A CN202111030242A CN113724906A CN 113724906 A CN113724906 A CN 113724906A CN 202111030242 A CN202111030242 A CN 202111030242A CN 113724906 A CN113724906 A CN 113724906A
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- OOAWCECZEHPMBX-UHFFFAOYSA-N oxygen(2-);uranium(4+) Chemical group [O-2].[O-2].[U+4] OOAWCECZEHPMBX-UHFFFAOYSA-N 0.000 title claims abstract description 138
- 238000002360 preparation method Methods 0.000 title claims abstract description 34
- FCTBKIHDJGHPPO-UHFFFAOYSA-N uranium dioxide Inorganic materials O=[U]=O FCTBKIHDJGHPPO-UHFFFAOYSA-N 0.000 claims abstract description 128
- 238000005245 sintering Methods 0.000 claims abstract description 67
- 239000008188 pellet Substances 0.000 claims abstract description 38
- 238000002156 mixing Methods 0.000 claims abstract description 16
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 15
- 239000011248 coating agent Substances 0.000 claims abstract description 7
- 238000000576 coating method Methods 0.000 claims abstract description 7
- 239000003758 nuclear fuel Substances 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 22
- 239000002245 particle Substances 0.000 claims description 19
- 238000007731 hot pressing Methods 0.000 claims description 18
- 238000009826 distribution Methods 0.000 claims description 15
- 238000002490 spark plasma sintering Methods 0.000 claims description 15
- 229910052770 Uranium Inorganic materials 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 229910052760 oxygen Inorganic materials 0.000 claims description 10
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 claims description 10
- 238000004321 preservation Methods 0.000 claims description 5
- 230000002708 enhancing effect Effects 0.000 claims description 3
- 238000000748 compression moulding Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- 239000006185 dispersion Substances 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 5
- 230000006872 improvement Effects 0.000 abstract description 3
- 239000000463 material Substances 0.000 description 15
- 238000001816 cooling Methods 0.000 description 11
- 229910052739 hydrogen Inorganic materials 0.000 description 10
- 239000001257 hydrogen Substances 0.000 description 8
- 235000015895 biscuits Nutrition 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- 229910009817 Ti3SiC2 Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 238000003825 pressing Methods 0.000 description 4
- 238000000280 densification Methods 0.000 description 3
- 229910003460 diamond Inorganic materials 0.000 description 3
- 239000010432 diamond Substances 0.000 description 3
- 238000005034 decoration Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 1
- WZECUPJJEIXUKY-UHFFFAOYSA-N [O-2].[O-2].[O-2].[U+6] Chemical compound [O-2].[O-2].[O-2].[U+6] WZECUPJJEIXUKY-UHFFFAOYSA-N 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910000439 uranium oxide Inorganic materials 0.000 description 1
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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
- G21C21/02—Manufacture of fuel elements or breeder elements contained in non-active casings
-
- 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
- G21C3/62—Ceramic fuel
- G21C3/623—Oxide fuels
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention relates to the technical field of nuclear fuels, in particular to a semi-continuous structure reinforced uranium dioxide pellet and a preparation method and application thereof. The preparation method provided by the invention comprises the following steps: carrying out self-spheroidizing treatment on the uranium dioxide to obtain loose uranium dioxide balls; and mixing and coating the loose uranium dioxide balls and the thermal conductivity reinforcing phase, and sintering to obtain the semi-continuous structure reinforced uranium dioxide pellet. Compared with the preparation method of the continuous structure reinforced uranium dioxide, the preparation method has the advantages of simple preparation process and good stability, and simultaneously basically keeps the heat conductivity improvement effect of the continuous structure; compared with the preparation method of the dispersion structure reinforced uranium dioxide, the preparation method has the advantage of better thermal conductivity reinforcing effect, and basically keeps the characteristics of simple preparation process and good stability of the dispersion structure.
Description
Technical Field
The invention relates to the technical field of nuclear fuels, in particular to a semi-continuous structure reinforced uranium dioxide pellet and a preparation method and application thereof.
Background
The nuclear fuel used in commercial pressurized water reactors at the present stage is mainly uranium dioxide. The uranium dioxide has a series of advantages of high melting point, good irradiation stability, water vapor corrosion resistance and the like. However, the thermal conductivity of uranium dioxide is very low, and it is difficult to lead fission heat out in time under accident conditions, so that the temperature of the core of the uranium dioxide pellet rises rapidly, and even the core is melted down. The improvement of the thermal conductivity of the uranium dioxide pellet is an important way for improving the safety of the uranium dioxide pellet under the accident condition, and is an effective method for improving the energy conversion efficiency under the normal working condition. At present, the technical means for improving the thermal conductivity of uranium dioxide is mainly like introducing a thermal conductivity enhancing phase into a core block.
The distribution mode of the thermal conductivity enhanced phase in the uranium dioxide at present mainly comprises a dispersion type distribution structure and a continuous type distribution structure; wherein continuous type distribution structure makes the heat conductivity reinforcing phase form the heat conduction passageway in the uranium dioxide base member, compares with the dispersion type distribution structure, has better reinforcing effect usually. The continuous distribution structure requires that the sintering temperature of the reinforcing phase and the uranium dioxide is close or the reinforcing phase and the uranium dioxide have excellent chemical compatibility. In order to realize the continuous distribution of the thermal conductivity enhanced phase, high-pressure pressing, mechanical crushing granulation and self-spheroidizing treatment are required to be carried out on the uranium dioxide powder, and the surface of spheroidized uranium dioxide particles is coated with the enhanced phase, so that the technical process is complex, the stability is difficult to control, and the method is not suitable for all enhanced phases. The dispersive distribution structure is suitable for all the reinforcing phases, and in order to realize the dispersive distribution of the thermal conductivity reinforcing phase, the thermal conductivity reinforcing phase and the uranium dioxide powder are only required to be uniformly mixed. The dispersion type distribution structure has the characteristics of simple process, good stability, good universality and the like, but the thermal conductivity enhancement effect is poor.
Therefore, the two distribution modes cannot simultaneously meet the requirements of good stability of the preparation process and good thermal conductivity enhancement effect.
Disclosure of Invention
The invention aims to provide a semi-continuous structure reinforced uranium dioxide core block and a preparation method and application thereof. The preparation method has the characteristics of simple preparation process, good stability and good thermal conductivity enhancement effect.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a semi-continuous structure reinforced uranium dioxide pellet, which comprises the following steps:
carrying out self-spheroidizing treatment on the uranium dioxide to obtain loose uranium dioxide balls;
and mixing and coating the loose uranium dioxide balls and the thermal conductivity reinforcing phase, and sintering to obtain the semi-continuous structure reinforced uranium dioxide pellet.
Preferably, the uranium dioxide235The enrichment degree of U is 0.2 wt%19 wt%, an oxygen-to-uranium ratio of 1.95 to 2.2, and a particle size of 0.5 to 20 μm.
Preferably, the rotation speed of the self-spheroidizing treatment is 150-400 r/min, and the time is 2-8 h.
Preferably, the diameter of the loose uranium dioxide ball is 100-400 mu m.
Preferably, the sintering mode comprises atmosphere sintering, hot-pressing sintering or spark plasma sintering.
Preferably, the atmosphere sintering comprises sequentially performing press forming and sintering under a reducing atmosphere;
the pressure of the compression molding is 100-600 MPa;
the sintering temperature in the reducing atmosphere is 1500-1900 ℃, the heating rate of the temperature to the sintering temperature in the reducing atmosphere is 1-10 ℃/min, and the time is 1-6 h.
Preferably, the temperature of the hot-pressing sintering is 1500-1700 ℃, the heating rate of the temperature to the temperature of the hot-pressing sintering is 2-20 ℃/min, the pressure is 30-50 MPa, and the heat preservation time is 0.5-4 h.
Preferably, the sintering temperature of the discharge plasma is 900-1650 ℃, the temperature is increased until the sintering temperature rate of the discharge plasma is 50-400 ℃/min, the pressure is 30-50 MPa, and the heat preservation time is 0.5-20 min.
The invention also provides a semicontinuous structure reinforced uranium dioxide pellet prepared by the preparation method in the technical scheme, which comprises uranium dioxide and a thermal conductivity reinforcing phase;
the thermal conductivity enhanced phase is in a semi-continuous distribution state in the uranium dioxide.
The invention also provides application of the semi-continuous structure reinforced uranium dioxide pellet in the technical scheme in the field of nuclear fuel.
The invention provides a preparation method of a semi-continuous structure reinforced uranium dioxide pellet, which comprises the following steps: carrying out self-spheroidizing treatment on the uranium dioxide to obtain loose uranium dioxide balls; and mixing and coating the loose uranium dioxide balls and the thermal conductivity reinforcing phase, and sintering to obtain the semi-continuous structure reinforced uranium dioxide pellet. Compared with the technology for improving the thermal conductivity of the uranium dioxide through a continuous structure in the prior art, the densified uranium dioxide ball is obtained through the processes of powder pressing, mechanical crushing, self-grinding spheroidization and the like; according to the preparation method, the loose uranium dioxide balls are obtained by directly carrying out self-spheroidizing treatment on the uranium dioxide, and the preparation method aims to greatly simplify the preparation process, improve the process stability and basically keep the heat conductivity improvement effect of a continuous structure.
Drawings
FIG. 1 is a preparation process of a semi-continuous structure reinforced uranium dioxide pellet according to the present invention;
FIG. 2 is a microstructure of semi-continuous structurally reinforced uranium dioxide pellets prepared in example 1;
fig. 3 is a graph comparing the thermal conductivities of the semi-continuous structure-reinforced uranium dioxide pellet prepared in example 1, the continuous structure-reinforced uranium dioxide pellet prepared in comparative example 1, and uranium dioxide.
Detailed Description
The invention provides a preparation method of a semi-continuous structure reinforced uranium dioxide pellet, which comprises the following steps:
carrying out self-spheroidizing treatment on the uranium dioxide to obtain loose uranium dioxide balls;
and mixing and coating the loose uranium dioxide spheres and the thermal conductivity enhanced phase, and sintering to obtain the semi-continuous structure enhanced uranium dioxide pellet (the preparation flow is shown in figure 1).
In the present invention, all the starting materials for the preparation are commercially available products known to those skilled in the art unless otherwise specified.
According to the invention, the loose uranium dioxide ball is obtained by carrying out self-spheroidizing treatment on the uranium dioxide.
In the invention, the uranium dioxide235The enrichment degree of U is preferably 0.2 to 19 wt%, more preferably 2 to 16 wt%, and most preferably 5 to 10 wt%; the ratio of oxygen to uranium is preferably 1.95-2.2, and more preferably 2.0-2.10; the particle size is preferably 0.5 to 20 μm, and more preferably 5 to 15 μm.
In the invention, the rotation speed of the self-spheroidizing treatment is preferably 150-400 r/min, more preferably 200-350 r/min, and most preferably 250-300 r/min; the time is preferably 2 to 8 hours, and more preferably 4 to 6 hours.
In the present invention, the self-spheroidizing treatment is preferably performed in a sealed pot.
In the invention, the self-spheroidizing condition can make the uranium dioxide powder in a distorted shape and can be mutually occluded to form loose uranium dioxide spheres (as shown in fig. 1).
In the invention, the diameter of the loose uranium dioxide ball is preferably 100-400 μm.
After obtaining the loose uranium dioxide spheres, the loose uranium dioxide spheres and the thermal conductivity reinforcing phase are mixed, coated and sintered to obtain the semi-continuous structure reinforced uranium dioxide core block.
The present invention is not limited to any particular kind of the thermal conductivity-enhancing phase, and the method may be performed by using a kind well known to those skilled in the art. In a specific embodiment of the invention, the thermal conductivity enhancing phase is specifically Ti3SiC2BeO, Mo, SiC, W or diamond micropowder.
In the invention, the particle size of the thermal conductivity enhanced phase is preferably 2-100 μm, and more preferably 5-20 μm.
In the invention, the volume ratio of the loose uranium dioxide spheres to the thermal conductivity enhanced phase is preferably (80-98): (2-20), more preferably (83-95): (5-16), most preferably (88-92): (8-12).
In the invention, the rotation speed of the mixed coating is preferably 100-250 r/min, and more preferably 150-200 r/min; the time is preferably 1 to 30min, more preferably 5 to 25min, and most preferably 10 to 20 min.
In the invention, the process of mixed cladding can make the thermal conductivity enhanced phase adhere to the surface of the loose uranium dioxide ball.
In the present invention, the sintering method preferably includes atmosphere sintering, hot press sintering, or spark plasma sintering.
In the present invention, the atmosphere sintering preferably includes press forming and sintering under a reducing atmosphere, which are sequentially performed. In the present invention, the pressure for the press molding is preferably 100 to 600MPa, more preferably 200 to 500MPa, and most preferably 200 to 400 MPa. In the present invention, the press molding functions to prepare a biscuit.
In the present invention, the reducing atmosphere is preferably a hydrogen atmosphere or an inert atmosphere containing hydrogen; when the reducing atmosphere is an inert atmosphere containing hydrogen, the present invention does not have any particular limitation on the kind and hydrogen content of the inert atmosphere, and those familiar to those skilled in the art can be used. In the present invention, the role of the reducing atmosphere is to maintain the uranium oxide ratio of the uranium dioxide.
In the invention, the sintering temperature under the reducing atmosphere is preferably 1500-1900 ℃; the heating rate of the temperature to the sintering temperature in the reducing atmosphere is preferably 1-10 ℃/min; the time is preferably 1-6 h. In the present invention, the sintering process under a reducing atmosphere is preferably: heating to 1600 ℃ at the speed of 10 ℃/min, heating to 1700 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 h; or heating to 1200 ℃ at the speed of 10 ℃/min, heating to 1750 ℃ at the speed of 5 ℃/min, and preserving heat for 4 h; or heating to 1400 deg.C at a rate of 10 deg.C/min, heating to 1780 deg.C at a rate of 2 deg.C/min, and maintaining for 8 hr.
In the present invention, the sintering under a reducing atmosphere functions to promote densification of the green compact, and the control of the sintering temperature, the temperature increase rate, and the time within the above ranges functions to control densification of the product.
In the present invention, the specific process of the atmosphere sintering is preferably: pressing and forming the material obtained after mixing and coating to obtain a biscuit; and sintering the biscuit in a reducing atmosphere.
In the present invention, the hot press sintering is preferably performed in a reducing atmosphere, which is preferably a hydrogen atmosphere or an inert atmosphere containing hydrogen; when the reducing atmosphere is an inert atmosphere containing hydrogen, the present invention does not have any particular limitation on the kind and hydrogen content of the inert atmosphere, and those familiar to those skilled in the art can be used. In the present invention, the role of the reducing atmosphere is to maintain the ratio of oxygen to uranium. The pressure of the hot-pressing sintering is preferably 30-50 MPa; the temperature is preferably 1500-1700 ℃; the heating rate of heating to the hot-pressing sintering temperature is preferably 2-20 ℃/min; the heat preservation time is preferably 0.5-4 h. In the invention, the hot-pressing sintering process preferably comprises the steps of heating to 1400-1600 ℃ at the speed of 2-20 ℃/min, heating to 1500-1700 ℃ at the speed of 2-5 ℃/min, and keeping the temperature for 0.5-4 h; more preferably, the temperature is raised to 1400 ℃ at the speed of 20 ℃/min, then raised to 1650 ℃ at the speed of 5 ℃/min, and the temperature is preserved for 0.5 h; or heating to 1600 ℃ at the speed of 15 ℃/min, heating to 1700 ℃ at the speed of 2 ℃/min, and keeping the temperature for 1 h.
In the present invention, the hot press sintering is preferably performed in a hot press sintering mold.
In the present invention, the hot press sintering functions to promote densification.
In the invention, the sintering temperature of the discharge plasma is preferably 900-1650 ℃, more preferably 1000-1600 ℃, and most preferably 1200-1500 ℃; the heating rate of the discharge plasma sintering is preferably 50-400 ℃/min, more preferably 100-300 ℃/min, and most preferably 150-250 ℃/min; the pressure is preferably 30-50 MPa; the heat preservation time is preferably 0.5-20 min, more preferably 5-15 min, and most preferably 8-12 min.
In the present invention, the spark plasma sintering is preferably performed in an SPS sintering mold.
In the invention, the discharge plasma sintering has the function of greatly reducing the sintering temperature and shortening the sintering time.
After the sintering is finished, the invention also preferably comprises cooling and demoulding which are carried out in sequence; the cooling mode is preferably furnace cooling; the target temperature of cooling is preferably room temperature-150 ℃; the present invention does not have any particular limitation on the release film, and the release film can be formed by a process known to those skilled in the art.
The invention also provides a semicontinuous structure reinforced uranium dioxide pellet prepared by the preparation method in the technical scheme, which comprises uranium dioxide and a thermal conductivity reinforcing phase;
the thermal conductivity enhanced phase is in a semi-continuous distribution state in the uranium dioxide.
In the invention, the volume ratio of the thermal conductivity enhanced phase to the uranium dioxide is preferably (2-20): (80-98), more preferably (5-16): (83-95), most preferably (8-12): (88-92).
The invention also provides application of the semi-continuous structure reinforced uranium dioxide pellet in the technical scheme in preparation of nuclear fuel. The method of the present invention is not particularly limited, and the method may be performed by a method known to those skilled in the art.
The semi-continuous structure reinforced uranium dioxide pellet provided by the present invention, the preparation method and the application thereof are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.
Example 1
Adding uranium dioxide235The enrichment degree of U is 0.2 wt%, the ratio of oxygen to uranium is 1.95, and the particle size is 2.5 mu m), the mixture is placed in a sealed tank and rotated for 2 hours at the rotating speed of 300r/min, and loose uranium dioxide balls (the particle size is 200 mu m) are obtained;
97.87g of loose uranium dioxide balls and 2.13g of Ti3SiC2(5 μm) is put into a mixing tank (corresponding to Ti)3 SiC 25 percent by volume), mixing for 20min at the rotating speed of 200r/min, placing the obtained mixed material in an SPS sintering mould for spark plasma sintering at the temperature of 1400 ℃, the heating rate of 200 ℃/min, the pressure of 50MPa and the time of 1min, cooling along with the furnace, and demoulding to obtain the semi-continuous structure reinforced uranium dioxide pellet;
wherein, FIG. 2 is a microstructure diagram of the semi-continuous structure reinforced uranium dioxide pellet, wherein the dark color area is Ti3SiC2Phase, light color area is uranium dioxide; as can be seen from FIG. 2, the Ti3SiC2The phases exhibit a semi-continuous distribution in the uranium dioxide.
Example 2
Adding uranium dioxide235The U enrichment degree is 19 wt%, the ratio of oxygen to uranium is 2.17, and the particle size is 1 mum) placing the uranium dioxide balls into a sealed tank, and rotating the sealed tank for 4 hours at the rotating speed of 150r/min to obtain loose uranium dioxide balls (the particle size is 100 mu m);
97.02g of loose uranium dioxide balls and 2.98g of BeO (5 mu m) are placed into a material mixing tank (corresponding to the volume fraction of the BeO of 10 percent), the loose uranium dioxide balls and the BeO are mixed for 20min at the rotating speed of 200r/min, the obtained mixed material is pressed under the condition of 100MPa to obtain a biscuit, and the biscuit is put in a reducing atmosphere (Ar-5 vol% H)2) And (3) sintering, namely heating the sintered material to 1200 ℃ at the speed of 10 ℃/min, heating the sintered material to 1750 ℃ at the speed of 5 ℃/min, preserving heat for 4h, cooling the sintered material to below 150 ℃ along with the furnace, and opening the furnace to obtain the semi-continuous structure reinforced uranium dioxide core block.
Example 3
Adding uranium dioxide235The U enrichment degree is 10 wt%, the ratio of oxygen to uranium is 2.2, and the particle size is 5 mu m), the mixture is placed in a sealed tank and rotated for 2 hours at the rotating speed of 400r/min, and loose uranium dioxide balls (the particle size is 400 mu m) are obtained;
98.14g of loose uranium dioxide balls and 1.86g of Mo (5 mu m) are placed into a material mixing tank (corresponding to the volume fraction of Mo of 2%), and after mixing is carried out for 30min at the rotating speed of 100r/min, the obtained mixed material is subjected to hot-pressing sintering in a hot-pressing sintering die, the pressure of the hot-pressing sintering is 30MPa, and the atmosphere of the hot-pressing sintering is Ar-5 vol% H2(ii) a Heating the hot-pressing sintering to 1400 ℃ at the speed of 20 ℃/min, heating to 1700 ℃ at the speed of 5 ℃/min, preserving heat for 0.5h, cooling to below 150 ℃ along with the furnace, and opening the furnace; and obtaining the semi-continuous structure reinforced uranium dioxide pellet.
Example 4
Adding uranium dioxide235The U enrichment degree is 4.45 wt%, the ratio of oxygen to uranium is 2.14, and the particle size is 1 mu m), the mixture is placed in a sealed tank and rotated for 8 hours at the rotating speed of 200r/min, and loose uranium dioxide balls (the particle size is 350 mu m) are obtained;
and (2) putting 92.66g of loose uranium dioxide balls and 7.34g of SiC (3 mu m) into a material mixing tank (corresponding to the volume fraction of the SiC is 15%), mixing at the rotating speed of 250r/min for 30min, putting the obtained mixed material into an SPS sintering mould for spark plasma sintering, wherein the temperature of the spark plasma sintering is 1450 ℃, the heating rate is 200 ℃/min, the pressure is 30MPa, and the time is 5min, cooling along with the furnace, and demoulding to obtain the semi-continuous structure reinforced uranium dioxide core block.
Example 5
Adding uranium dioxide235The enrichment degree of U is 5 wt%, the ratio of oxygen to uranium is 2.00, and the particle size is 2 mu m), the mixture is placed in a sealed tank and rotated for 4 hours at the rotating speed of 200r/min, and loose uranium dioxide balls (the particle size is 150 mu m) are obtained;
83.6g of loose uranium dioxide balls and 16.4g W (3 mu m) are placed into a material mixing tank (corresponding to the volume fraction of W of 10 percent), the loose uranium dioxide balls and the 16.4g W (3 mu m) are mixed for 30min at the rotating speed of 250r/min, the obtained mixed material is pressed and molded under the condition of 400MPa to obtain a biscuit, and the biscuit is put into a reducing atmosphere (Ar-5 vol% H)2) And (3) sintering, namely heating to 1400 ℃ at the speed of 10 ℃/min, heating to 1780 ℃ at the speed of 2 ℃/min, preserving heat for 8h, cooling to below 150 ℃ along with the furnace, and opening the furnace to obtain the semi-continuous structure reinforced uranium dioxide pellet.
Example 6
Adding uranium dioxide235The enrichment degree of U is 15 wt%, the ratio of oxygen to uranium is 2.08, and the particle size is 10 mu m), the mixture is placed in a sealed tank and rotated for 6 hours at the rotating speed of 300r/min, and loose uranium dioxide balls (the particle size is 350 mu m) are obtained;
98.35g of loose uranium dioxide balls and 1.65g of diamond micro powder (16 mu m) are placed in a material mixing tank (corresponding to the volume fraction of diamond is 5 percent), after being mixed for 15min at the rotating speed of 150r/min, the obtained mixed material is subjected to hot-pressing sintering in a hot-pressing sintering die, the pressure of the hot-pressing sintering is 50MPa, and the atmosphere of the hot-pressing sintering is Ar-5 vol% H2(ii) a Heating the hot-pressing sintering to 1600 ℃ at the speed of 15 ℃/min, heating to 1650 ℃ at the speed of 5 ℃/min, keeping the temperature for 1h, cooling to below 150 ℃ along with the furnace, and opening the furnace; and obtaining the semi-continuous structure reinforced uranium dioxide pellet.
Comparative example 1
Adding uranium dioxide235The U enrichment degree is 0.2 wt%, the ratio of oxygen to uranium is 1.95, and the grain diameter is 2.5 mu m) is placed in a hard alloy die, and the pressure of 600MPa is applied to obtain a uranium dioxide pre-pressing blank. Then crushing in a mortar, sieving the crushed particles with 30-mesh and 100-mesh sieves to obtain the uranium dioxide with the mesh number of 30-100And (3) granules. And then, spheroidizing the uranium dioxide particles in a nylon tank for 8 hours at the rotating speed of 200r/min to obtain compact uranium dioxide pellets. 97.87g of uranium dioxide pellets and 2.13g of Ti3SiC2(5 μm) powder was placed in a stainless steel jar (corresponding to Ti)3SiC2Volume fraction of 5%) for 2h, and rotating speed of the stainless steel tank at 100 r/min.
Mixing uranium dioxide pellets-Ti3SiC2And placing the mixture in an SPS sintering mould for spark plasma sintering, wherein the temperature of the spark plasma sintering is 1400 ℃, the heating rate is 200 ℃/min, the pressure is 50MPa, the time is 1min, and furnace cooling and demoulding are carried out to obtain the continuously reinforced uranium dioxide pellet.
Test example
The semi-continuous structure reinforced uranium dioxide core blocks prepared in the embodiments 1-6, the continuous reinforced uranium dioxide core blocks prepared in the comparative example 1 and the uranium dioxide are subjected to thermal conductivity tests at different temperatures (25 ℃,200 ℃,400 ℃,600 ℃,800 ℃ and 1000 ℃), and the test standard is GB/22588-.
Fig. 3 is a comparison graph of thermal conductivities of the semi-continuous structure-reinforced uranium dioxide pellet prepared in example 1 and the continuous structure-reinforced uranium dioxide pellet and uranium dioxide prepared in comparative example 1, and as can be seen from fig. 3, the thermal conductivities of the semi-continuous structure-reinforced uranium dioxide pellet and the continuous structure-reinforced uranium dioxide pellet are very close to each other, but the preparation process is simpler than that of comparative example 1 and the process stability is higher; the purer uranium dioxide is improved to a certain degree;
the thermal conductivity of the semi-continuous structure reinforced uranium dioxide core blocks and uranium dioxide prepared in the embodiments 1 to 6 at 1000 ℃ is shown in table 1:
table 1 thermal conductivity of semi-continuous structure-reinforced uranium dioxide pellets and uranium dioxide prepared in examples 1 to 6 at 1000 ℃
| Examples | Thermal conductivity (W.m)-1·K-1) | Increase ratio (%) compared with uranium dioxide |
| Example 1 | 3.21 | 15％ |
| Example 2 | 4.19 | 50％ |
| Example 3 | 3.35 | 20％ |
| Example 4 | 4.05 | 45％ |
| Example 5 | 5.02 | 80％ |
| Example 6 | 4.2 | 50％ |
| Comparative example 1 | 3.27 | 17％ |
| Uranium dioxide | 2.79 | --- |
As can be seen from Table 1, the semi-continuous structure reinforced uranium dioxide core block prepared by the preparation method can effectively improve the thermal conductivity.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A preparation method of a semi-continuous structure reinforced uranium dioxide pellet is characterized by comprising the following steps:
carrying out self-spheroidizing treatment on the uranium dioxide to obtain loose uranium dioxide balls;
and mixing and coating the loose uranium dioxide balls and the thermal conductivity reinforcing phase, and sintering to obtain the semi-continuous structure reinforced uranium dioxide pellet.
2. The method of claim 1 wherein the uranium dioxide is235The enrichment degree of U is 0.2-19 wt%, the ratio of oxygen to uranium is 1.95-2.2, and the particle size is 0.5-20 mu m.
3. The method according to claim 1, wherein the self-spheroidizing process is performed at a rotation speed of 150 to 400r/min for 2 to 8 hours.
4. The method of claim 1 wherein the loose uranium dioxide spheres have a diameter of 100 to 400 μm.
5. The method of claim 1, wherein the sintering comprises atmosphere sintering, hot press sintering, or spark plasma sintering.
6. The production method according to claim 5, wherein the atmosphere sintering comprises press forming and sintering under a reducing atmosphere, which are performed in this order;
the pressure of the compression molding is 100-600 MPa;
the sintering temperature in the reducing atmosphere is 1500-1900 ℃, the heating rate of the temperature to the sintering temperature in the reducing atmosphere is 1-10 ℃/min, and the time is 1-6 h.
7. The preparation method according to claim 5, wherein the temperature of the hot-pressing sintering is 1500-1700 ℃, the heating rate of the temperature to the temperature of the hot-pressing sintering is 2-20 ℃/min, the pressure is 30-50 MPa, and the holding time is 0.5-4 h.
8. The preparation method according to claim 5, wherein the temperature of the spark plasma sintering is 900-1650 ℃, the temperature is raised until the temperature raising rate of the spark plasma sintering is 50-400 ℃/min, the pressure is 30-50 MPa, and the heat preservation time is 0.5-20 min.
9. A semi-continuous structure reinforced uranium dioxide pellet prepared by the preparation method of any one of claims 1 to 8, which is characterized by comprising uranium dioxide and a thermal conductivity enhancing phase;
the thermal conductivity enhanced phase is in a semi-continuous distribution state in the uranium dioxide.
10. Use of semi-continuous structurally reinforced uranium dioxide pellets according to claim 9 in the field of nuclear fuels.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103299375A (en) * | 2010-09-27 | 2013-09-11 | 普渡研究基金会 | Ceramic-ceramic composites and process therefor, nuclear fuels formed thereby, and nuclear reactor systems and processes operated therewith |
| US20160232993A1 (en) * | 2013-11-26 | 2016-08-11 | Joint Stock Company "Akme-Engineering" | Nuclear Fuel Pellet Having Enhanced Thermal Conductivity, and Preparation Method Thereof |
| CN107274936A (en) * | 2017-07-03 | 2017-10-20 | 中国工程物理研究院材料研究所 | A kind of fast preparation method of the enhanced uranium dioxide nuclear fuel of beryllium oxide |
| CN108335760A (en) * | 2018-02-01 | 2018-07-27 | 中国工程物理研究院材料研究所 | A kind of preparation method of high uranium useful load dispersion fuel pellet |
| CN109671511A (en) * | 2018-12-19 | 2019-04-23 | 中国工程物理研究院材料研究所 | A kind of preparation method of monocrystalline high thermal conductivity uranium dioxide fuel ball |
-
2021
- 2021-09-03 CN CN202111030242.1A patent/CN113724906A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103299375A (en) * | 2010-09-27 | 2013-09-11 | 普渡研究基金会 | Ceramic-ceramic composites and process therefor, nuclear fuels formed thereby, and nuclear reactor systems and processes operated therewith |
| US20160232993A1 (en) * | 2013-11-26 | 2016-08-11 | Joint Stock Company "Akme-Engineering" | Nuclear Fuel Pellet Having Enhanced Thermal Conductivity, and Preparation Method Thereof |
| CN107274936A (en) * | 2017-07-03 | 2017-10-20 | 中国工程物理研究院材料研究所 | A kind of fast preparation method of the enhanced uranium dioxide nuclear fuel of beryllium oxide |
| CN108335760A (en) * | 2018-02-01 | 2018-07-27 | 中国工程物理研究院材料研究所 | A kind of preparation method of high uranium useful load dispersion fuel pellet |
| CN109671511A (en) * | 2018-12-19 | 2019-04-23 | 中国工程物理研究院材料研究所 | A kind of preparation method of monocrystalline high thermal conductivity uranium dioxide fuel ball |
Non-Patent Citations (1)
| Title |
|---|
| 李锐;高家诚;杨晓东;孟繁琦;: "二氧化铀核燃料芯块烧结工艺的发展概况", 材料导报, no. 02, pages 91 - 93 * |
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