CN115838292A - Preparation method of uranium carbonitride fuel - Google Patents
Preparation method of uranium carbonitride fuel Download PDFInfo
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- CN115838292A CN115838292A CN202211383989.XA CN202211383989A CN115838292A CN 115838292 A CN115838292 A CN 115838292A CN 202211383989 A CN202211383989 A CN 202211383989A CN 115838292 A CN115838292 A CN 115838292A
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- 229910052770 Uranium Inorganic materials 0.000 title claims abstract description 74
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 239000000446 fuel Substances 0.000 title claims abstract description 62
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000000843 powder Substances 0.000 claims abstract description 100
- 239000004372 Polyvinyl alcohol Substances 0.000 claims abstract description 52
- 229920002451 polyvinyl alcohol Polymers 0.000 claims abstract description 52
- 238000005245 sintering Methods 0.000 claims abstract description 48
- MVXWAZXVYXTENN-UHFFFAOYSA-N azanylidyneuranium Chemical compound [U]#N MVXWAZXVYXTENN-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000007789 gas Substances 0.000 claims abstract description 33
- 238000002156 mixing Methods 0.000 claims abstract description 32
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 28
- 239000011812 mixed powder Substances 0.000 claims abstract description 28
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 27
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000000725 suspension Substances 0.000 claims abstract description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 16
- 239000000463 material Substances 0.000 claims abstract description 14
- 229920000049 Carbon (fiber) Polymers 0.000 claims abstract description 13
- 239000007864 aqueous solution Substances 0.000 claims abstract description 13
- 239000004917 carbon fiber Substances 0.000 claims abstract description 13
- 238000001035 drying Methods 0.000 claims abstract description 13
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000002041 carbon nanotube Substances 0.000 claims abstract description 8
- 229910021393 carbon nanotube Inorganic materials 0.000 claims abstract description 8
- 239000001257 hydrogen Substances 0.000 claims abstract description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 20
- 239000002245 particle Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 238000004321 preservation Methods 0.000 claims description 6
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000007873 sieving Methods 0.000 claims description 5
- 239000003575 carbonaceous material Substances 0.000 abstract description 5
- 239000008188 pellet Substances 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- 230000008569 process Effects 0.000 description 8
- 239000003758 nuclear fuel Substances 0.000 description 7
- 238000005086 pumping Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 5
- 238000005253 cladding Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000001291 vacuum drying Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 235000015842 Hesperis Nutrition 0.000 description 1
- 235000012633 Iberis amara Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 description 1
- QRKOGTOMYRGNOR-UHFFFAOYSA-N methane;uranium Chemical compound C.[U] QRKOGTOMYRGNOR-UHFFFAOYSA-N 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- OOAWCECZEHPMBX-UHFFFAOYSA-N oxygen(2-);uranium(4+) Chemical compound [O-2].[O-2].[U+4] OOAWCECZEHPMBX-UHFFFAOYSA-N 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000011882 ultra-fine particle Substances 0.000 description 1
- 150000003671 uranium compounds Chemical class 0.000 description 1
- FCTBKIHDJGHPPO-UHFFFAOYSA-N uranium dioxide Inorganic materials O=[U]=O FCTBKIHDJGHPPO-UHFFFAOYSA-N 0.000 description 1
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- 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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Abstract
The application provides a preparation method of a uranium carbonitride fuel, which comprises the following steps: adding a carbon-containing material into a polyvinyl alcohol aqueous solution to obtain a polyvinyl alcohol suspension, wherein the carbon material comprises at least one of carbon fibers and carbon nano tubes; will U 3 O 8 Mixing the powder and the polyvinyl alcohol suspension and drying to obtain mixed powder; sintering the mixed powder under the condition of introducing flowing hydrogen to obtain uranium carbide powder; sintering the uranium carbide powder under the condition of introducing mixed gas formed by mixing nitrogen and active gas to obtain uranium nitride powder; and mixing the uranium carbide powder and the uranium nitride powder according to a first preset proportion, and sintering to obtain the uranium carbonitride fuel.
Description
Technical Field
The application relates to the technical field of nuclear fuel preparation, in particular to a preparation method of uranium carbonitride fuel.
Background
The uranium carbonitride U (C, N) fuel has the characteristics of high heat conductivity and high uranium density, and the novel high-performance fuel can be used as a candidate fuel for next-generation high-performance elements. In the related art, the preparation of uranium carbonitride U (C, N) fuel is often carried outBy mixing UO 2 Mixing the powder with carbon powder at N 2 And reacting at high temperature under the condition.
However, the uranium carbonitride U (C, N) fuel prepared by the method has the technical problems of low purity and reactivity and difficulty in controlling the stoichiometric ratio of C to N in the fuel.
Disclosure of Invention
In view of the above, the present application provides a method for preparing uranium carbonitride fuel, so as to at least partially solve the above existing technical problems.
In order to solve the technical problem, the application provides a preparation method of a uranium carbonitride fuel, which comprises the following steps:
adding a carbon-containing material into a polyvinyl alcohol aqueous solution to obtain a polyvinyl alcohol suspension, wherein the carbon-containing material comprises at least one of carbon fibers and carbon nano tubes;
will U 3 O 8 Mixing the powder and the polyvinyl alcohol suspension and drying to obtain mixed powder;
sintering the mixed powder under the condition of introducing flowing hydrogen to obtain uranium carbide powder;
sintering the uranium carbide powder under the condition of introducing mixed gas formed by mixing nitrogen and active gas to obtain uranium nitride powder;
and mixing the uranium carbide powder and the uranium nitride powder according to a first preset proportion, and sintering to obtain the uranium carbonitride fuel.
According to the embodiment of the application, the mass fraction of the polyvinyl alcohol aqueous solution is 1-3%; the mass ratio of the carbon-containing material in the polyvinyl alcohol aqueous solution to the polyvinyl alcohol is 1-10%.
According to an embodiment of the present application, the carbon fibers and the carbon nanotubes have a particle size ranging from 300 to 900nm.
According to the embodiment of the application, U 3 O 8 Mixing the powder with the polyvinyl alcohol suspension and drying to obtain mixed powder comprising: mixing the above U and C at a molar ratio of 1 (3-9) 3 O 8 Mixing the powder with the above suspensionLiquid; and drying the mixed solution to obtain mixed powder.
According to the embodiment of the present application, after the mixed liquid is dried, the dried powder is pulverized and sieved to obtain the mixed powder.
According to embodiments of the present application, the mesh size ranges from 100 to 120 mesh.
According to the embodiment of this application, under the circumstances of letting in flowing hydrogen, carry out sintering treatment to mixed powder, obtain the uranium carbide powder and include:
putting the mixed powder into a first sintering furnace, vacuumizing, and heating to a first temperature; after the heat preservation is carried out for the first time at the first temperature, flowing hydrogen is introduced, and the mixed powder is sintered at the second temperature to obtain uranium carbide powder.
According to the embodiment of the application, the pressure in the first sintering furnace after vacuum pumping ranges from (2 to 4) multiplied by 10 -3 Pa; the first temperature range is 1300-1500 ℃; the first time length range is 1-3 hours; the second temperature range is 1400-1600 ℃.
According to an embodiment of the application, the reactive gas is at least one of: NH (NH) 3 And H 2 。
According to the examples of the present application, the ratio of the active gas to the nitrogen gas ranges from 4 to 6%.
According to the embodiment of this application, under the circumstances of letting in the mist that forms by nitrogen gas and active gas mixture, carry out sintering treatment to uranium carbide powder, obtain uranium nitride powder and include:
and putting the uranium carbide powder into a second sintering furnace, vacuumizing and then introducing the mixed gas, heating to a third temperature and keeping the temperature for a second time to obtain uranium nitride powder.
According to the embodiment of the application, the pressure in the second sintering furnace after vacuum pumping ranges from (2 to 4) multiplied by 10 -3 Pa; the third temperature range is 1300-1700 ℃; the second time period ranges from 1 to 3 hours.
According to an embodiment of the application, the first preset ratio range is 1: (1-1.2).
According to the embodiment of this application, mix uranium carbide powder and uranium nitride powder according to first preset proportion, and obtain the uranium carbonitride fuel after carrying out sintering treatment and include:
mixing the uranium carbide powder and the uranium nitride powder according to a first preset proportion, and sintering under the sintering conditions that the pressure is 60-80 MPa, the temperature is 1450-1650 ℃, and the heat preservation time is 5-15 min to obtain the uranium carbonitride fuel.
According to the examples of the present application, two forms of carbon source (polyvinyl alcohol (PVA) and carbonaceous material) and U are added 3 O 8 The powder reaction for preparing the UC powder can increase the mixing uniformity of the UC powder, improve the reaction activity and the product purity, and improve the purity of the UC powder and the UN powder from the source. Meanwhile, the carbon fiber is used as a solid carbon source with high thermal conductivity and high strength, so that the thermophysical property of the fuel can be obviously improved.
According to the embodiment of the application, the UC powder and the UN powder are mixed to prepare the uranium carbonitride, the C/N stoichiometric ratio can be accurately controlled, and the C/N random proportioning design of the U (C, N) fuel pellet is realized.
Drawings
FIG. 1 is a flow diagram of the present application for producing a uranium carbonitride fuel;
FIG. 2 is a flow chart of the present application for preparing uranium carbide powder;
fig. 3 is a flow chart of the present application for preparing uranium nitride powder.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described clearly and completely in conjunction with the embodiments of the present application. It should be apparent that the described embodiment is one embodiment of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the application without any inventive step, are within the scope of protection of the application.
It is to be noted that, unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which this application belongs. If the description "first", "second", etc. is referred to throughout, the description of "first", "second", etc. is used only for distinguishing similar objects, and is not to be construed as indicating or implying a relative importance, order or number of technical features indicated, it being understood that the data described in "first", "second", etc. may be interchanged where appropriate. If "and/or" is presented throughout, it is meant to include three juxtapositions, exemplified by "A and/or B" and including either scheme A, or scheme B, or schemes in which both A and B are satisfied.
The uranium element can be used as nuclear fuel in a nuclear fission phenomenon, the space nuclear reactor fuel element is required to have high power and long service life in the field of space nuclear power, and in view of the fact that the single component of uranium cannot meet the overall requirement of the space nuclear reactor fuel element, the method provides the method that other elements are added on the basis of the single component to form a ternary uranium compound so as to improve the comprehensive performance of the fuel.
The uranium-bearing density of the Uranium Carbide (UC) fuel is as high as 12.96t/m; the thermal conductivity at 1237K is 21.7W/(m.K), which is about 8 times that of uranium dioxide, and the material is considered to be a novel nuclear fuel with excellent performance. The Uranium Nitride (UN) fuel has excellent performances of high uranium density, high thermal conductivity and high temperature stability, so that the UN fuel becomes a preferred fuel for future space reactor power, space nuclear power and nuclear power rockets. However, the conventional high-temperature fuel element adopts W and Mo materials as cladding, but the compatibility of uranium carbide and uranium carbide with special cladding materials (W and Mo-based materials) has a problem. Wherein the UC fuel can carburize the W cladding, and the W is generated after the UC fuel is maintained for 1300 hours 2 The C layer may be up to 0.5 μm thick. The UC fuel has a sharp increase in osmotic strength with increasing temperature. Keeping for 30h at 2000 ℃ 2 The thickness of the C layer can be increased to 383 μm. The permeability of UC fuel in Mo material is especially high, and the thickness of MoC layer can reach 150 μm after being kept at 1200 ℃ for 3600 h. For UN, when the temperature reaches about 1700 ℃, the UN 0.985 Which may be considered the lower boundary of the homogeneous zone. At this composition, the nitrogen pressure exceeds the uranium partial pressure by about 4 orders of magnitude. This indicates that the total amount of liquid uranium in the UN will increase as the composition of the UN moves to the lower boundary. This indicates that the high temperature fuel element using W and Mo as cladding is not suitable for selectionTwo-component fuel with UC and UN. Uranium carbonitride [ U (C, N) for increasing reactor power and for deepening burnup depth]Fuel performance needs to be further optimized. In the related art, the preparation method of U (C, N) fuel usually adopts UO 2 Mixing the powder with carbon powder at N 2 And reacting at high temperature under the condition.
However, this process has significant disadvantages: one is UO 2 The powder and the solid carbon powder are difficult to be mixed uniformly, so that the carbon-poor area UO is formed 2 The reaction is incomplete, and the super-carbon region generates multi-carbide, so that the phase purity of the fuel is influenced, and the performance of the fuel is reduced; second, pure N 2 The N-N covalent bond has higher energy and lower reaction activity, needs higher reaction temperature and longer reaction time and has large energy consumption; thirdly, under the condition of excessively high reaction temperature, uranium nitride is decomposed, so that the fuel C and the fuel N are difficult to reach the designed stoichiometric ratio.
Fig. 1 schematically shows a flow chart for preparing a uranium carbonitride fuel according to the present application.
As shown in fig. 1, the present application proposes a method for preparing a uranium carbonitride fuel, which includes operations S101 to S105.
In operation S101, adding a carbon-containing material to a polyvinyl alcohol aqueous solution to obtain a polyvinyl alcohol suspension, wherein the carbon-containing material includes at least one of carbon fibers and carbon nanotubes;
in operation S102, U is added 3 O 8 Mixing the powder and the polyvinyl alcohol suspension and drying to obtain mixed powder;
in operation S103, sintering the mixed powder under the condition of flowing hydrogen gas, so as to obtain uranium carbide powder;
in operation S104, sintering the uranium carbide powder while introducing a mixed gas formed by mixing nitrogen and an active gas, to obtain uranium nitride powder;
in operation S105, uranium carbide powder and uranium nitride powder are mixed according to a first preset ratio, and are sintered to obtain a uranium carbonitride fuel.
According to the examples of the present application, two forms of carbon source (p) were addedolyvinyl alcohol, PVA and carbonaceous material) with U 3 O 8 The UC powder is prepared by powder reaction, so that the mixing uniformity of the UC powder can be increased, and the reaction activity and the product purity are improved; meanwhile, the carbon fiber is used as a solid carbon source with high thermal conductivity and high strength, so that the thermophysical property of the fuel can be obviously improved.
According to the embodiment of the application, the mass fraction of the polyvinyl alcohol aqueous solution comprises 1-3%.
According to the embodiment of the present application, the mass fraction of the polyvinyl alcohol aqueous solution may be selected to be, for example, 1%, 2%, 3%, or the like.
According to the embodiment of the application, the mass ratio of the carbonaceous material to the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 1-10%.
According to the embodiment of the application, the mass ratio of the carbonaceous material to the polyvinyl alcohol in the polyvinyl alcohol aqueous solution can be selected to be 1%, 5%, 10%, and the like.
According to the examples of the present application, the aqueous polyvinyl alcohol solution functions as follows: firstly, providing a carbon source; and secondly, the polyvinyl alcohol aqueous solution has good cohesiveness, is beneficial to the development of processes such as granulation, pressing and the like in the nuclear fuel manufacturing technology, and prepares the nuclear fuel with excellent performance.
According to an embodiment of the present application, the particle size range of the carbon fibers and the carbon nanotubes includes 300 to 900nm.
According to an embodiment of the present application, the particle size of the carbon fiber and the carbon nanotube may be selected to be 300nm, 500nm, 600nm, 900nm, etc.
According to the embodiment of the application, U 3 O 8 Mixing the powder with the polyvinyl alcohol suspension and drying to obtain mixed powder comprising: mixing the above U and C at a molar ratio of 1 (3-9) 3 O 8 Powder and the polyvinyl alcohol suspension to obtain a mixed solution; and drying the mixed solution to obtain mixed powder.
According to the examples of the present application, the molar ratio of U and C can be selected from 1.
According to the embodiment of the present application, during the preparation of UC, excess C is used, which can be reacted with U 3 O 8 The powder is subjected to a sufficient carbon-oxygen reaction,helping to reduce oxygen impurities in the product.
According to the embodiment of the present application, after the mixed liquid is dried, the dried powder is pulverized and sieved to obtain the mixed powder. According to the examples of the present application, the dried powder is pulverized and sieved to obtain a mixed powder having an ultrafine particle size.
According to the embodiment of the present application, the pulverized powder may be subjected to a sieving process using a sieve.
According to embodiments of the present application, the mesh number of the screen is in the range of 100-120 mesh.
According to the embodiment of the application, the mesh number of the screen can be selected to be 100 meshes, 110 meshes, 120 meshes and the like.
Fig. 2 schematically shows a flow chart of the present application for preparing uranium carbide powder.
As shown in fig. 2, according to an embodiment of the present application, preparing uranium carbide powder includes operations S201 to S203.
In operation S201, placing the mixed powder into a first sintering furnace, vacuumizing, and heating to a first temperature;
in operation S202, after maintaining the temperature at the first temperature for a first time period, flowing hydrogen gas is introduced;
in operation S203, the mixed powder is sintered at a second temperature to obtain uranium carbide powder.
According to the embodiment of the application, the pressure in the first sintering furnace after vacuum pumping ranges from (2 to 4) multiplied by 10 -3 Pa。
According to the embodiment of the application, the pressure in the first sintering furnace after vacuum pumping can be selected to be 5 x 10 -3 Pa、6×10 -3 Pa、7×10 -3 Pa, and the like.
According to an embodiment of the application, the first temperature range is 1300 to 1500 ℃.
According to an embodiment of the present application, the first temperature may be selected to be 1300 ℃, 1400 ℃, 1500 ℃, and the like.
According to an embodiment of the present application, the first time period ranges from 1 to 3 hours.
According to an embodiment of the present application, the first duration may be selected to be 1 hour, 2 hours, 3 hours, and the like.
According to an embodiment of the application, the second temperature range is 1400-1600 ℃.
According to an embodiment of the present application, the second temperature may be selected to be 1400 ℃, 1500 ℃, 1600 ℃, etc.
According to the examples of the present application, H is at high temperature 2 Can remove trace carbon elements in the mixed powder, and the principle of carbon removal is C +2H 2 →CH 4 。
According to an embodiment of the application, the reactive gas is at least one of: NH (NH) 3 And H 2 。
According to the embodiment of the application, NH is selected as the active gas 3 And H 2 The activity of nitrogen in the atmosphere can be improved without introducing other impurities.
The principle of the mixed gas introduction for preparing synthetic UN powder according to the embodiment of the application is UC + NH 3 +N 2 →UN+CH 4 。
According to an embodiment of the present application, the ratio range of the active gas to the nitrogen gas is: 4 to 6 percent.
According to the embodiment of the present application, the ratio of the active gas to the nitrogen gas may be selected to be in a range of 4%, 5%, 6%, and the like.
Fig. 3 schematically shows a flow chart for preparing uranium nitride powder according to the present application. As shown in fig. 3, according to an embodiment of the present application, preparing uranium nitride powder includes operations S301 to S303.
In operation S301, the uranium carbide powder is placed in a second sintering furnace, and vacuum pumping is performed;
in operation S302, a mixed gas formed by mixing nitrogen and an active gas is introduced;
in operation S303, the temperature is raised to a third temperature and kept for a second time to obtain uranium nitride powder.
According to the embodiment of the application, the pressure in the second sintering furnace after vacuum pumping ranges from (2 to 4) multiplied by 10 -3 Pa。
According to the embodiment of the application, the pressure in the second sintering furnace after vacuum pumping can be selected to be 2 x 10 -3 Pa、3×10 - 3 Pa、4×10 -3 Pa, and the like.
According to an embodiment of the present application, the third temperature range is 1300-1700 ℃.
According to an embodiment of the present application, the third temperature range may be selected to be 1300 ℃, 1500 ℃, 1700 ℃, and the like.
According to an embodiment of the application, the second period of time ranges from 1 to 3 hours.
According to an embodiment of the present application, the second time period may be selected to be 1 hour, 2 hours, 3 hours, and the like.
According to an embodiment of the present application, the first predetermined ratio range is 1 (1-1.2).
According to an embodiment of the present application, the first preset ratio range may be selected from 1, 1.1, 1.2.
According to the embodiment of the application, the uranium carbonitride fuel obtained by mixing uranium carbide powder and uranium nitride powder according to a first preset proportion and sintering the mixture comprises:
mixing the uranium carbide powder and the uranium nitride powder according to a first preset proportion, and sintering under the sintering conditions that the pressure is 60-80 MPa, the temperature is 1450-1650 ℃, and the heat preservation time is 5-15 min to obtain the uranium carbonitride fuel.
According to the embodiment of the application, the pressure of the uranium carbonitride fuel in the process of preparing the uranium carbonitride fuel can be selected to be 60MPa, 70MPa, 80MPa and the like.
According to the embodiment of the application, the temperature of the uranium carbonitride fuel in the process of preparing the uranium carbonitride fuel can be selected to be 1450 ℃, 1550 ℃, 1650 ℃ and the like.
According to the embodiment of the application, the heat preservation time of the uranium carbonitride fuel can be selected to be 5min, 10min, 15min and the like in the process of preparing the uranium carbonitride fuel.
According to the embodiment of the application, the pellet prepared by the preparation method for preparing the uranium carbonitride fuel can reach the relative density of more than 92 percent TD, the C/N ratio is close to 1.
According to embodiments of the present application, the relative density is equal to the true density divided by the theoretical density.
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail with reference to specific embodiments below. It should be noted that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. Other embodiments, which can be derived by one of ordinary skill in the art from the embodiments given herein without making any creative effort, shall fall within the scope of the present disclosure.
Example 1
A method for preparing uranium carbonitride fuel, comprising:
s1: an aqueous polyvinyl alcohol (PVA) solution was prepared in a mass ratio of 1% by weight, and carbon fibers (having a particle size of 300 nm) and the polyvinyl alcohol (PVA) solution were mixed in a mass ratio of 1% by weight, and dispersed by ultrasonic waves for 30 minutes to obtain a PVA suspension.
S2: respectively measuring U according to the molar ratio of U to C being 1 3 O 8 Dispersing powder and PVA suspension by ultrasonic wave for 60min, drying in vacuum drying oven for 1 hr, taking out powder, crushing, sieving with 100 mesh sieve, placing in high temperature sintering furnace, and vacuumizing to pressure of 5 × 10 -3 After Pa, the temperature is raised to 1300 ℃, the temperature is kept for 1H, and then flowing H is introduced 2 Keeping the temperature of the gas at 1400 ℃ for 2h to obtain high-purity UC powder.
S3: placing the UC powder prepared by the S2 into a high-temperature sintering furnace, and vacuumizing the high-temperature sintering furnace until the pressure is 2 multiplied by 10 - 3 After Pa, introducing flowing mixed gas with the component of N 2 And NH 3 Wherein NH 3 The volume of (c) is 5% of the total mixed gas volume. And (3) preserving the temperature for 1h at the temperature of 1300 ℃ to synthesize UN powder.
S4: mixing the UC powder prepared in the step S2 and the UN powder prepared in the step S3 according to the mol ratio of 1.
The C/N ratio of the fuel pellets produced according to example 1 of the present application was 1.08, with an oxygen content of 66ppm and a pellet density of 92.1% TD.
Example 2
A method for preparing uranium carbonitride fuel, comprising:
s1: an aqueous polyvinyl alcohol (PVA) solution was prepared at a mass ratio of 2% by weight, and carbon fibers (particle size: 600 nm) and the polyvinyl alcohol (PVA) solution were mixed at a mass ratio of 5% by weight, and ultrasonically dispersed for 40min to obtain a PVA suspension.
S2: respectively measuring U according to the molar ratio of U to C of 1 3 O 8 Dispersing the powder and PVA suspension by ultrasonic wave for 120min, drying in a vacuum drying oven for 2h, taking out the powder, crushing, sieving with a 150-mesh sieve, placing in a high-temperature sintering furnace, and vacuumizing the high-temperature sintering furnace to 6 × 10 -3 After Pa, the temperature is raised to 1400 ℃, the temperature is kept for 2H, and then flowing H is introduced 2 And (3) preserving the temperature of the gas for 3 hours at the temperature of 1500 ℃ to obtain high-purity UC powder.
S3: placing the UC powder prepared by the S2 into a high-temperature sintering furnace, and vacuumizing the high-temperature sintering furnace until the pressure is 3 multiplied by 10 - 3 After Pa, introducing flowing mixed gas with the component of N 2 And NH 3 Wherein NH 3 The volume of the mixed gas (D) is 5 percent of the volume of the total mixed gas, and the UN powder is synthesized after heat preservation for 2 hours at the temperature of 1500 ℃.
S4: and (3) mixing the UC powder prepared in the step (S2) and the UN powder prepared in the step (S3) according to the mol ratio of 1.1, applying an SPS sintering process, and preserving heat for 10min under the conditions that the pressure is 70MPa and the temperature is 1550 ℃ to prepare the fuel U (C, N) fuel pellet.
The C/N ratio of the fuel pellets produced according to example 2 of the present application was 1.05 and the O content was 63ppm. Pellet density was 92.5% td.
Example 3
A method for preparing uranium carbonitride fuel, comprising:
s1: preparing an aqueous polyvinyl alcohol (PVA) solution in a mass ratio of 3% by weight, mixing the carbon fibers (having a particle size of 900 nm) and the polyvinyl alcohol (PVA) solution in a mass ratio of 9% by weight, and ultrasonically dispersing for 50min to obtain a PVA suspension.
S2: respectively measuring U according to the molar ratio of U to C of 1 3 O 8 Dispersing the powder and PVA suspension by ultrasonic wave for 180min, drying in a vacuum drying oven for 1-3 h, taking out the powder, crushing, sieving with a 200-mesh sieve, placing in a high-temperature sintering furnace, and vacuumizing the high-temperature sintering furnace to a pressure of 7 × 10 -3 After Pa, the temperature is raised to 1500 ℃, the temperature is kept for 3 hours, and then flowing H is introduced 2 And (3) preserving the temperature of the gas for 4 hours at 1600 ℃ to obtain high-purity UC powder.
S3: placing the UC powder prepared by the S2 into a high-temperature sintering furnace, and vacuumizing the high-temperature sintering furnace until the pressure is 4 multiplied by 10 - 3 After Pa, introducing flowing mixed gas with the component of N 2 And NH 3 Wherein NH 3 The volume of (c) is 5% of the total mixed gas volume. And (3) preserving the temperature for 3h at the temperature of 1700 ℃, and synthesizing UN powder.
S4: and (3) mixing the UC powder obtained in the step (S2) and the UN powder obtained in the step (S3) according to the mol ratio of 1.2, applying an SPS sintering process, and keeping the temperature for 15min under the conditions that the pressure is 80MPa and the temperature is 1650 ℃ to obtain the fuel U (C, N) fuel pellet.
The C/N ratio of the fuel pellets produced according to example 3 of the present application was 1.03, the O content was 59ppm, the pellet density was 92.9% TD.
The present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. The prior art can be used for all the matters not described in detail in this application.
Claims (10)
1. A method for preparing uranium carbonitride fuel, comprising:
adding a carbon-containing material into a polyvinyl alcohol aqueous solution to obtain a polyvinyl alcohol suspension, wherein the carbon-containing material comprises at least one of carbon fibers and carbon nanotubes;
will U 3 O 8 Mixing powder with the polyvinyl alcohol suspension and drying to obtain mixed powder;
sintering the mixed powder under the condition of introducing flowing hydrogen to obtain uranium carbide powder;
sintering the uranium carbide powder under the condition of introducing mixed gas formed by mixing nitrogen and active gas to obtain uranium nitride powder;
and mixing the uranium carbide powder and the uranium nitride powder according to a first preset proportion, and sintering to obtain the uranium carbonitride fuel.
2. The production method according to claim 1, wherein the mass fraction of the polyvinyl alcohol aqueous solution is 1 to 3%; the mass ratio of the carbon-containing material to the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 1-10%.
3. The method of claim 1 or 2, wherein the carbon fibers and carbon nanotubes have a particle size ranging from 300 to 900nm.
4. The method according to claim 1, wherein the addition of U is carried out 3 O 8 Mixing powder and the polyvinyl alcohol suspension and drying to obtain mixed powder, wherein the mixed powder comprises:
mixing the U and the C according to the molar ratio of 1 (3-9) 3 O 8 Powder and the polyvinyl alcohol suspension to obtain a mixed solution;
and drying the mixed solution to obtain the mixed powder.
5. The method of manufacturing according to claim 4, further comprising:
and after the mixed solution is dried, crushing the dried powder, and sieving to obtain the mixed powder.
6. The method of claim 5, wherein the mesh size is in the range of 100-120 mesh.
7. The preparation method according to claim 1, wherein the sintering treatment of the mixed powder while flowing hydrogen gas is introduced to obtain uranium carbide powder comprises:
putting the mixed powder into a first sintering furnace, vacuumizing, and heating to a first temperature; and after the heat preservation is carried out for the first time at the first temperature, the flowing hydrogen is introduced, and the mixed powder is subjected to sintering treatment at the second temperature to obtain the uranium carbide powder.
8. The production method according to claim 7, wherein the pressure in the first sintering furnace after the evacuation is in a range of (5 to 7) x 10 -3 Pa; the first temperature range is 1300-1500 ℃; the first time length range is 1-3 hours; the second temperature range is 1400-1600 ℃.
9. The production method according to claim 1, wherein a ratio of the active gas to the nitrogen gas is in a range of 4 to 6%.
10. The production method according to claim 9, wherein the sintering of the uranium carbide powder by introducing a mixed gas formed by mixing nitrogen and an active gas to obtain the uranium nitride powder comprises:
and putting the uranium carbide powder into a second sintering furnace, introducing the mixed gas after vacuumizing, heating to a third temperature, and keeping the temperature for a second time to obtain the uranium nitride powder.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3527578A (en) * | 1966-10-06 | 1970-09-08 | Mitsubishi Metal Corp | Production of uranium-nitrogen compounds |
| US10562771B1 (en) * | 2017-02-06 | 2020-02-18 | Triad National Security, Llc | Fabrication of uranium nitride |
| CN115171932A (en) * | 2022-05-12 | 2022-10-11 | 中核北方核燃料元件有限公司 | Preparation method of UC ceramic microspheres |
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- 2022-11-07 CN CN202211383989.XA patent/CN115838292A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3527578A (en) * | 1966-10-06 | 1970-09-08 | Mitsubishi Metal Corp | Production of uranium-nitrogen compounds |
| US10562771B1 (en) * | 2017-02-06 | 2020-02-18 | Triad National Security, Llc | Fabrication of uranium nitride |
| CN115171932A (en) * | 2022-05-12 | 2022-10-11 | 中核北方核燃料元件有限公司 | Preparation method of UC ceramic microspheres |
Non-Patent Citations (1)
| Title |
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| MASAAKI U: "Compressive creep of sintered UC-UN solid solutions", JOURNAL OF NUCLEAR MATERIALS, vol. 49, no. 1, pages 91 - 97 * |
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