Inert matrix dispersed nuclear fuel powder pretreatment method
By spherical processing and mixing and sieving of nuclear fuel particles and inert matrix powder, the problem of uneven dispersion of nuclear fuel particles and inert matrix in traditional mechanical mixing methods is solved, achieving uniform distribution and structural stability of nuclear fuel particles in inert matrix, and improving the performance and lifespan of dispersed nuclear fuel.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU NUCLEAR TECH ENG DESIGN & RES INST CO LTD
- Filing Date
- 2025-06-24
- Publication Date
- 2026-06-12
Smart Images
Figure CN122201871A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the technical field of transmutation fuel preparation, and more particularly to a method for pretreatment of inert-based dispersed nuclear fuel powder. Background Technology
[0002] Dispersed nuclear fuel is a multiphase nuclear fuel. Traditional preparation methods primarily employ mechanical mixing, which involves physically mixing nuclear fuel particles with inert dispersion medium powder, then pressing and sintering the mixture. However, significant differences in physical properties typically exist between the nuclear fuel particles and the inert matrix, manifested as large density differences and mismatched particle size distributions. This makes it difficult for traditional mechanical mixing processes to achieve uniform dispersion of the two materials, leading to localized agglomeration of the nuclear fuel particles within the inert matrix. Agglomeration results in non-uniform heat flow distribution in dispersed nuclear fuel under irradiation conditions, inducing localized overheating risks. It also exacerbates mechanical stress concentration in the fuel particles, significantly increasing the probability of particle breakage and limiting the performance and service life of dispersed nuclear fuel. Furthermore, when traditional mechanical mixing methods are applied to the mixing of nuclear fuel particles and lightweight inert matrices, severe phase separation occurs during the mixing process due to gravitational sorting and electrostatic adsorption, leading to structural failure.
[0003] Therefore, it is necessary to propose a pretreatment method for inert-based dispersed nuclear fuel powder to at least partially solve the problems existing in the prior art. Summary of the Invention
[0004] This disclosure aims to address at least one of the technical problems existing in the prior art or related technologies.
[0005] Therefore, this disclosure proposes a pretreatment method for inert-based dispersed nuclear fuel powder.
[0006] In view of this, according to embodiments of the present disclosure, a pretreatment method for inert-based dispersed nuclear fuel powder is proposed, comprising:
[0007] Nuclear fuel particles are processed to obtain spherical nuclear fuel particles;
[0008] The inert matrix powder is pre-spheroidized to obtain spherical inert matrix powder;
[0009] The above-mentioned spherical nuclear fuel particles and the above-mentioned spherical inert matrix powder are placed in a mixing tank for mixing and sieving to obtain inert matrix dispersed transmutation fuel powder.
[0010] In one feasible embodiment, when the inert matrix powder is MgO matrix powder, the diameter of the spherical nuclear fuel particles is 100 μm to 500 μm; the diameter of the spherical MgO matrix powder obtained after the pre-spheroidization treatment of the MgO matrix powder is 50 μm to 500 μm.
[0011] In one feasible implementation, the above-described steps of processing nuclear fuel particulate material to obtain spherical nuclear fuel particles include:
[0012] The above-mentioned fuel particle material was subjected to a first ball milling operation at a first rotation speed, and the first ball milling time was continued to obtain the first nuclear fuel particle.
[0013] The first nuclear fuel particles were subjected to a second ball milling operation at a second rotation speed for a second ball milling time to obtain the spherical nuclear fuel particles.
[0014] Wherein, the first rotational speed is greater than the second rotational speed; the first ball milling time is less than the second ball milling time; and the first grinding ball particle size in the first ball milling operation is greater than the second grinding ball particle size in the second ball milling operation.
[0015] In one feasible implementation, the first rotational speed is 250 rpm to 300 rpm; the second rotational speed is 100 rpm to 150 rpm.
[0016] The first ball milling time is 30 to 50 minutes; the second ball milling time is 100 to 200 minutes; the first grinding ball particle size is 10 to 20 mm; and the second grinding ball particle size is 3 to 5 mm.
[0017] In one feasible embodiment, when the inert matrix powder is MgO matrix powder, the step of pre-spheroidizing the inert matrix powder to obtain spherical inert matrix powder includes:
[0018] The above MgO matrix powder was placed in ultrapure water, and polyvinyl alcohol adhesive was added. After stirring evenly, a slurry was obtained.
[0019] The slurry was spray-granulated to obtain the above-mentioned spherical MgO matrix powder.
[0020] In one feasible embodiment, the polyvinyl alcohol adhesive accounts for 0.2% to 1.6% of the slurry;
[0021] The concentration of the MgO matrix powder in the above slurry is 5% to 25%.
[0022] In one feasible embodiment, the inlet air temperature for the above-mentioned spray granulation is 200°C to 280°C; the fan speed is 1.2 m / s.3 / min to 2m 3 / min; outlet air temperature is 80℃ to 90℃.
[0023] In one feasible embodiment, when the inert matrix powder is MgO matrix powder, the step of mixing the spherical nuclear fuel particles and the spherical inert matrix powder in a mixing tank and then sieving them to obtain inert matrix dispersed transmutation fuel powder includes:
[0024] The above-mentioned spherical nuclear fuel particles and the above-mentioned spherical inert matrix powder are placed into the above-mentioned mixing tank, and a lubricant is added to the above-mentioned mixing tank to obtain a first mixture.
[0025] Add grinding balls to the above mixing tank and perform ball milling on the first mixture at a preset time and preset speed to obtain a second mixture;
[0026] The second mixture was poured into a sieve for sieving to obtain MgO-based dispersed transmutation fuel powder.
[0027] In one feasible embodiment, the lubricant comprises zinc stearate lubricant, wherein the content of zinc stearate lubricant is 0.2 wt% to 0.5 wt%.
[0028] The aforementioned screens include 100-mesh to 150-mesh screens.
[0029] In one feasible embodiment, the above-mentioned pretreatment method for inert-based dispersed nuclear fuel powder further includes:
[0030] The above-mentioned inert-based dispersed transmutation fuel powder is subjected to pressing and sintering to obtain inert-based dispersed transmutation fuel pellets.
[0031] In the case where the inert-based dispersed transmutation fuel pellets are MgO-based dispersed transmutation fuel pellets, the pressure of the pressing operation is 120 MPa to 210 MPa; and the temperature of the sintering operation is 1600°C to 1700°C.
[0032] Compared to existing technologies, this disclosure offers at least the following advantages: The inert-based dispersed nuclear fuel powder pretreatment method provided in this disclosure processes nuclear fuel particulate material to obtain spherical nuclear fuel particles; pre-spheroidizes inert matrix powder to obtain spherical inert matrix powder; and mixes and sieves the spherical nuclear fuel particles and the spherical inert matrix powder in a mixing tank to obtain inert-based dispersed transmutation fuel powder. By modifying the morphology of the inert matrix powder and optimizing the particle size of the nuclear fuel particles, the particle size distribution of the nuclear fuel particles and the inert matrix powder can be synergistically controlled to solve the problem of uneven mechanical mixing caused by the mismatch of physical properties of heterogeneous materials. This overcomes the bottleneck of phase separation caused by a significant density gradient between nuclear fuel particles and inert matrix powder in traditional mechanical mixing processes, avoiding structural failure; and achieves uniform cross-size distribution of the nuclear fuel phase in the inert matrix, eliminating the problem of non-uniform heat flow distribution and local overheating caused by the irradiation hot spot effect resulting from local agglomeration of nuclear fuel particles. Attached Figure Description
[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0034] Figure 1 A schematic flowchart illustrating an embodiment of the inert-based dispersed nuclear fuel powder pretreatment method provided in this disclosure;
[0035] Figure 2 A schematic morphology diagram of the original MgO matrix powder provided in one embodiment of this disclosure;
[0036] Figure 3 A schematic topographic diagram of CeO2, the original nuclear fuel, provided in one embodiment of this disclosure;
[0037] Figure 4 A schematic morphology diagram of MgO matrix powder after spray granulation according to an embodiment of this disclosure;
[0038] Figure 5 This is a schematic morphological diagram of a sintered MgO-based dispersed nuclear fuel simulation pellet according to one embodiment of the present disclosure. Detailed Implementation
[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the description of these embodiments is intended to aid in understanding the invention, but does not constitute a limitation thereof. The specific structural and functional details disclosed herein are merely for describing exemplary embodiments of the invention. However, the invention can be embodied in many alternative forms and should not be construed as being limited to the embodiments described herein.
[0040] like Figure 1 As shown, according to an embodiment of this disclosure, a pretreatment method for inert-based dispersed nuclear fuel powder is proposed, comprising:
[0041] Step S110: Process the nuclear fuel particulate material to obtain spherical nuclear fuel particles; Step S120: Pre-spheroidize the inert-based powder to obtain spherical inert-based powder; Step S130: Place the above-mentioned spherical nuclear fuel particles and the above-mentioned spherical inert-based powder into a mixing tank for mixing and sieving to obtain inert-based dispersed transmutation fuel powder.
[0042] It is understood that the inert-based dispersed nuclear fuel powder pretreatment method provided in this disclosure pretreatment method obtains spherical nuclear fuel particles by processing nuclear fuel particulate material; obtains spherical inert matrix powder by pre-spheroidizing inert matrix powder; and obtains inert-based dispersed transmutation fuel powder by mixing and sieving the spherical nuclear fuel particles and the spherical inert matrix powder in a mixing tank. By modifying the morphology of the inert matrix powder and optimizing the particle size of the nuclear fuel particles, the particle size distribution of the nuclear fuel particles and the inert matrix powder can be synergistically controlled to solve the problem of uneven mechanical mixing caused by the mismatch of physical properties of heterogeneous materials. This overcomes the bottleneck of phase separation caused by the significant density gradient between nuclear fuel particles and inert matrix powder in traditional mechanical mixing processes, avoiding structural failure; and achieves uniform cross-size distribution of the nuclear fuel phase in the inert matrix, eliminating the problem of non-uniform heat flow distribution and local overheating caused by the irradiation hot spot effect resulting from local agglomeration of nuclear fuel particles.
[0043] In some examples, when the inert base powder is MgO matrix powder, the diameter of the spherical nuclear fuel particles is 100 μm to 500 μm; the diameter of the spherical MgO matrix powder obtained after the pre-spheroidization treatment of the MgO matrix powder is 50 μm to 500 μm.
[0044] Understandably, MgO is considered an ideal inert matrix material for nuclear waste transmutation and advanced fuel cycles due to its excellent thermal stability, low neutron absorption cross section, high radiation stability, and economic advantages. This is because the density of typical oxide nuclear fuels is approximately 10 g / cm³. 3 The density of MgO is 3.58 g / cm³.3 Due to the mismatch in particle size distribution, it is difficult to achieve uniform dispersion of the two materials using traditional mechanical mixing processes. This can be addressed by processing the nuclear fuel particles to obtain spherical nuclear fuel particles with a diameter of 100 μm to 500 μm. Correspondingly, the MgO matrix powder is pre-spheroidized to obtain spherical MgO matrix powder with a diameter of 50 μm to 500 μm. By modifying the surface and controlling the particle size of the spherical nuclear fuel particles and spherical MgO matrix powder, phase separation caused by gravity separation and electrostatic adsorption in traditional mechanical mixing is avoided, improving mixing uniformity, alleviating nuclear fuel particle agglomeration, enhancing interfacial bonding, and improving the dispersion uniformity and structural stability of the nuclear fuel particles.
[0045] For example, CeO2 particulate material can be used as the nuclear fuel particulate material. A schematic diagram of the morphology of CeO2 particulate material is shown below. Figure 3 As shown, and Figure 2 As can be seen from the schematic diagram of the morphology of the MgO matrix powder, the density difference between MgO and CeO2 is large, and their particle size distributions are mismatched.
[0046] In some examples, the steps of processing nuclear fuel particulate material to obtain spherical nuclear fuel particles include: performing a first ball milling operation on the fuel particulate material at a first rotational speed for a first ball milling time to obtain first nuclear fuel particles; performing a second ball milling operation on the first nuclear fuel particles at a second rotational speed for a second ball milling time to obtain the spherical nuclear fuel particles; wherein the first rotational speed is greater than the second rotational speed; the first ball milling time is less than the second ball milling time; and the diameter of the first grinding ball in the first ball milling operation is greater than the diameter of the second grinding ball in the second ball milling operation.
[0047] It is understandable that stepped ball milling can be used to process nuclear fuel particles to obtain spherical nuclear fuel particles. Specifically, the nuclear fuel particles can be placed in a ball mill jar, and the first grinding balls can be added. The first ball milling operation is performed at a first rotational speed for a first grinding time, thus obtaining the first nuclear fuel particles. Subsequently, a second grinding ball is used to perform a second ball milling operation on the first nuclear fuel particles at a second rotational speed for a second grinding time. The first rotational speed is greater than the second rotational speed, the first grinding time is less than the second grinding time, and the particle size of the first grinding balls is larger than that of the second grinding balls. This first ball milling operation provides preliminary processing, followed by a second ball milling operation for fine processing, ensuring the quality of the ball milling process and obtaining spherical nuclear fuel particles, improving reliability. Furthermore, ball milling is a dry forming process, offering good process compatibility and economy, and reducing processing costs.
[0048] For example, both the first and second grinding balls can be ZrO2 grinding balls.
[0049] In some examples, the first rotational speed is 250 rpm to 300 rpm; the second rotational speed is 100 rpm to 150 rpm; the first milling time is 30 min to 50 min; the second milling time is 100 min to 200 min; the first milling ball diameter is 10 mm to 20 mm; and the second milling ball diameter is 3 mm to 5 mm.
[0050] Understandably, the first rotational speed can be selected from 250 rpm to 300 rpm, the first ball milling time can be selected from 30 min to 50 min, and the particle size of the first grinding balls can be selected from 10 mm to 20 mm. This setup allows for rapid ball milling of the nuclear fuel particles in the first ball milling operation to initially obtain the first nuclear fuel particles, thus improving efficiency. The second rotational speed can be selected from 100 rpm to 150 rpm, the second ball milling time can be selected from 100 min to 200 min, and the particle size of the second grinding balls can be selected from 3 mm to 5 mm. This setup allows for fine ball milling of the first nuclear fuel particles in the second ball milling operation to improve the conversion rate of the nuclear fuel particles to spherical nuclear fuel particles.
[0051] In some examples, when the inert matrix powder is MgO matrix powder, the step of pre-spheroidizing the inert matrix powder to obtain spherical inert matrix powder includes: placing the MgO matrix powder in ultrapure water, adding polyvinyl alcohol adhesive, stirring evenly to obtain a slurry; and spray granulating the slurry to obtain the spherical MgO matrix powder.
[0052] Understandably, when using MgO as the inert matrix powder, pre-spheroidization treatment can be performed to obtain spherical MgO matrix powder. Specifically, MgO matrix powder can be placed in ultrapure water, and polyvinyl alcohol binder can be added. After stirring evenly, a slurry is obtained. Subsequently, the slurry is spray-granulated to obtain spherical MgO matrix powder. Spray granulation uses mechanical atomization to disperse the slurry into atomized microparticles, which are then dried with hot air to instantly evaporate the atomized microparticles, thus achieving particle formation and ensuring that the spherical MgO matrix powder has high sphericity and uniform particle size.
[0053] In some examples, the polyvinyl alcohol adhesive accounts for 0.2% to 1.6% of the slurry; the concentration of the MgO matrix powder in the slurry is 5% to 25%.
[0054] It is understandable that the polyvinyl alcohol adhesive can account for 0.2% to 1.6% of the slurry, and the concentration of MgO matrix powder in the slurry is 5% to 25%, in order to ensure the effect of spray granulation and to ensure that the spherical MgO matrix powder has the characteristics of high sphericity and uniform particle size.
[0055] In some examples, the inlet air temperature for the above-mentioned spray granulation is 200°C to 280°C; the fan speed is 1.2 m / s. 3 / min to 2m 3 / min; outlet air temperature is 80℃ to 90℃.
[0056] Understandably, in spray granulation operations, the inlet air temperature can be adjusted to 200℃ to 280℃, and the fan speed can be adjusted to 1.2m. 3 / min to 2m 3 The speed is increased to achieve instantaneous evaporation of the dispersed slurry atomized particles by hot air, so as to ensure that the spherical MgO matrix powder has the characteristics of high sphericity and uniform particle size.
[0057] For example, such as Figure 2 The diagram shows the morphology of the MgO matrix powder, revealing irregular particle sizes and mismatched particle size distribution. Pretreatment of the MgO matrix powder involves placing it in ultrapure water and adding polyvinyl alcohol (PVA) binder. After thorough stirring, a slurry is obtained, containing 15% MgO matrix powder and 1% PVA binder. Spray granulation is performed under the following conditions: inlet air temperature of 240℃ and fan speed set at 1.6 m / s². 3 The air flow rate is [speed] / min, and the outlet temperature is 85℃. A schematic diagram of the morphology of the treated spherical MgO matrix powder is shown below. Figure 4 As shown, the pre-spheroidized spherical MgO matrix powder has a uniform particle size distribution and relatively uniform particle size, and the particle size increases significantly under the action of polyvinyl alcohol adhesive.
[0058] In some examples, when the inert matrix powder is MgO matrix powder, the step of mixing and sieving the spherical nuclear fuel particles and the spherical inert matrix powder in a mixing tank to obtain inert matrix dispersion transmutation fuel powder includes: placing the spherical nuclear fuel particles and the spherical inert matrix powder into the mixing tank and adding a lubricant to the mixing tank to obtain a first mixture; adding grinding balls to the mixing tank and ball milling the first mixture at a preset time and preset speed to obtain a second mixture; and pouring the second mixture into a sieve for sieving to obtain MgO matrix dispersion transmutation fuel powder.
[0059] Understandably, when MgO matrix powder is used as the inert matrix powder, after pretreating the MgO matrix powder to obtain spherical MgO matrix powder and pretreating the nuclear fuel particles to obtain spherical nuclear fuel particles, the spherical nuclear fuel particles and spherical MgO matrix powder can be added to a mixing tank in a certain proportion. A lubricant is then added to the mixing tank to obtain a first mixture. To disperse the smaller MgO agglomerates, grinding balls can be added to the mixing tank, and the first mixture can be ball-milled at a preset time and speed to obtain a second mixture. The second mixture is then poured into a sieve for sieving. After repeated sieving multiple times, MgO-matrix dispersed transmutation fuel powder can be obtained. By modifying the morphology of the inert matrix powder and optimizing the particle size of the nuclear fuel particles, the particle size distribution of the nuclear fuel particles and MgO matrix powder can be synergistically controlled to solve the problem of uneven mechanical mixing caused by the mismatch of physical properties of heterogeneous materials. This breakthrough overcomes the bottleneck of phase separation caused by the significant density gradient between nuclear fuel particles and MgO matrix powder in traditional mechanical mixing processes, thus avoiding structural failure. It achieves uniform distribution of nuclear fuel phase across dimensions in the MgO matrix, eliminating the problem of non-uniform heat flow distribution and local overheating caused by the irradiation hot spot effect resulting from local agglomeration of nuclear fuel particles.
[0060] It should be noted that the ratio of spherical nuclear fuel particles to spherical MgO matrix powder can be 1:4 to 1:6 to ensure sufficient mixing and mixing effect.
[0061] In some examples, the lubricant includes zinc stearate lubricant, the content of which is 0.2 wt% to 0.5 wt%; the screen includes a 100-mesh to 150-mesh screen.
[0062] Understandably, zinc stearate lubricant can be used, with a content of 0.2wt% to 0.5wt% to ensure lubrication effect. A 100-mesh to 150-mesh screen can be used, and repeated sieving can ensure screening effect.
[0063] For example, spherical nuclear fuel particles and spherical MgO matrix powder are selected and placed in a mixing tank at a ratio of 1:4, and then 0.4 wt% zinc stearate lubricant is added to obtain a first mixture. ZrO2 grinding balls are added to the mixing tank, and the ball milling time is 1 hour at a speed of 5 to 10 rpm. After the ball milling operation is completed, the resulting second mixture is poured into a 100-mesh sieve and sieved twice to obtain MgO matrix dispersed transmutation fuel powder.
[0064] In some examples, the above-mentioned pretreatment method for inert-based dispersed nuclear fuel powder further includes: pressing and sintering the inert-based dispersed transmutation fuel powder to obtain inert-based dispersed transmutation fuel pellets; wherein, when the inert-based dispersed transmutation fuel pellets are MgO-based dispersed transmutation fuel pellets, the pressure of the pressing operation is 120 MPa to 210 MPa; and the temperature of the sintering operation is 1600°C to 1700°C.
[0065] Understandably, after obtaining inert-based dispersed transmutation fuel powder, it can be pressed and sintered to obtain inert-based dispersed transmutation fuel pellets. When the inert-based dispersed transmutation fuel powder is MgO-based dispersed transmutation fuel powder, the pressure applied to the MgO-based dispersed transmutation fuel powder during the pressing process can be 120 MPa to 210 MPa. After pressing, the sintering temperature is controlled at 1600℃ to 1700℃ to ensure the quality of the formed MgO-based dispersed transmutation fuel pellets.
[0066] like Figure 5 The diagram shows the morphology of a simulated MgO matrix dispersed nuclear fuel pellet after sintering. It can be seen that the spherical MgO matrix powder and spherical nuclear fuel particles are evenly distributed, avoiding structural failure. The nuclear fuel phase is evenly distributed across the inert matrix, eliminating the problem of non-uniform heat flow distribution and local overheating caused by the irradiation hot spot effect resulting from the local agglomeration of nuclear fuel particles.
[0067] It should be understood that the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit, without departing from the scope of the exemplary embodiments of the invention.
[0068] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.
[0069] It should be understood that in the description of this invention, the terms "upper," "vertical," "inner," "outer," etc., indicate the orientation or positional relationship as commonly placed when the disclosed product is used, or the orientation or positional relationship commonly understood by those skilled in the art. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0070] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0071] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” “containing,” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, and do not exclude the presence or addition of one or more other features, quantities, steps, operations, units, components, and / or combinations thereof.
[0072] Specific details are provided in the following description to provide a complete understanding of the exemplary embodiments. However, those skilled in the art will understand that the exemplary embodiments can be implemented without these specific details. In other embodiments, well-known processes, structures, and techniques may be omitted in the depiction of non-essential details to avoid obscuring the exemplary embodiments.
[0073] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
[0074] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art.
Claims
1. A method for pretreatment of inert-based dispersed nuclear fuel powder, characterized in that, include: Nuclear fuel particles are processed to obtain spherical nuclear fuel particles; The inert matrix powder is pre-spheroidized to obtain spherical inert matrix powder; The spherical nuclear fuel particles and the spherical inert matrix powder are placed in a mixing tank for mixing and sieving to obtain inert matrix dispersed transmutation fuel powder.
2. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 1, characterized in that, When the inert matrix powder is MgO matrix powder, the diameter of the spherical nuclear fuel particles is 100 μm to 500 μm; the diameter of the spherical MgO matrix powder obtained after the MgO matrix powder pre-spheroidization treatment is 50 μm to 500 μm.
3. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 2, characterized in that, The step of processing nuclear fuel particulate material to obtain spherical nuclear fuel particles includes: The fuel particle material is subjected to a first ball milling operation at a first rotation speed, and the first ball milling time is continued to obtain the first nuclear fuel particle. The first nuclear fuel particles are subjected to a second ball milling operation at a second rotation speed, and the second ball milling time is continued to obtain the spherical nuclear fuel particles. Wherein, the first rotational speed is greater than the second rotational speed; the first ball milling time is less than the second ball milling time; and the first grinding ball particle size in the first ball milling operation is greater than the second grinding ball particle size in the second ball milling operation.
4. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 3, characterized in that, The first speed is 250 rpm to 300 rpm; the second speed is 100 rpm to 150 rpm; The first ball milling time is 30 to 50 minutes; the second ball milling time is 100 to 200 minutes; the particle size of the first grinding ball is 10 to 20 mm; and the particle size of the second grinding ball is 3 to 5 mm.
5. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 2, characterized in that, When the inert matrix powder is MgO matrix powder, the step of pre-spheroidizing the inert matrix powder to obtain spherical inert matrix powder includes: The MgO matrix powder was placed in ultrapure water, and polyvinyl alcohol adhesive was added. After stirring evenly, a slurry was obtained. The slurry is spray-granulated to obtain the spherical MgO matrix powder.
6. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 5, characterized in that, The polyvinyl alcohol adhesive accounts for 0.2% to 1.6% of the slurry; The concentration of the MgO matrix powder in the slurry is 5% to 25%.
7. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 5, characterized in that, The inlet air temperature for the spray granulation is 200℃ to 280℃; the fan speed is 1.2m. 3 / min to 2m 3 / min; outlet air temperature is 80℃ to 90℃.
8. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 2, characterized in that, When the inert matrix powder is MgO matrix powder, the step of mixing the spherical nuclear fuel particles and the spherical inert matrix powder in a mixing tank and then sieving them to obtain inert matrix dispersed transmutation fuel powder includes: The spherical nuclear fuel particles and the spherical inert matrix powder are placed into the mixing tank, and a lubricant is added to the mixing tank to obtain a first mixture. Grinding balls are added to the mixing tank, and the first mixture is ball-milled at a preset time and a preset speed to obtain a second mixture. The second mixture is poured into a sieve for sieving to obtain MgO-based dispersed transmutation fuel powder.
9. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 8, characterized in that, The lubricant includes zinc stearate lubricant, wherein the content of zinc stearate lubricant is from 0.2 wt% to 0.5 wt%. The screen includes 100-mesh to 150-mesh screens.
10. The pretreatment method for inert-based dispersed nuclear fuel powder according to claim 1, characterized in that, Also includes: The inert-based dispersed transmutation fuel powder is subjected to pressing and sintering to obtain inert-based dispersed transmutation fuel pellets. Wherein, when the inert-based dispersed transmutation fuel pellet is an MgO-based dispersed transmutation fuel pellet, the pressing pressure is 120 MPa to 210 MPa; and the sintering temperature is 1600°C to 1700°C.