Uranium dioxide powder stabilization system, post-processing system and stabilization method

Abstract

The present invention proposes a uranium dioxide powder stabilization system, a post-processing system, and a stabilization treatment method. The uranium dioxide powder stabilization system includes a treatment unit, a feed unit, and a stabilized air intake unit. The feed unit is connected to the treatment unit, through which uranium dioxide powder enters the treatment unit. The stabilized air intake unit is connected to the treatment unit, and the stabilized air intake unit introduces an oxygen-containing gas mixture into the treatment unit to stabilize the uranium dioxide powder in the treatment unit. The system is characterized in that it also includes an isolation unit connected to the feed unit. The isolation unit controls the opening and closing of the feed unit and prevents hydrogen and / or water vapor in the feed unit from entering the treatment unit when closed. The uranium dioxide powder stabilization system proposed in this application, by providing an isolation unit, prevents hydrogen and water vapor in the preparation unit from entering the treatment unit, thereby improving the oxygen-uranium ratio of uranium dioxide and achieving continuous treatment.

Description

Technical Field

[0001] The present invention relates to the field of nuclear chemical technology, and in particular to a uranium dioxide powder stabilization system, a post-processing system and a stabilization method. Background Art

[0002] With my country's increasing emphasis on environmental protection, the country's nuclear fuel element manufacturing industry has gradually shifted from wet processes to dry processes for producing uranium dioxide powder. The dry process is already well established and utilizes an integrated converter to generate uranium dioxide powder through an integrated reaction between gaseous uranium hexafluoride, water vapor, and hydrogen.

[0003] However, in actual production, dry processes often require the introduction of excess hydrogen to minimize the fluorine content of the product. This excess hydrogen reduces the oxygen-uranium ratio in the uranium dioxide powder. Furthermore, this excess hydrogen can enter the post-processing steps of the uranium dioxide powder, further affecting the oxygen-uranium ratio of the final uranium dioxide. Therefore, post-processing the low-oxygen-uranium ratio uranium dioxide powder produced by the dry process to prevent hydrogen from entering subsequent processing steps and thereby improve the oxygen-uranium ratio of the uranium dioxide has become a pressing issue. Furthermore, converting the dry process to a continuous discharge process requires continuous collection and prevention of water vapor from entering the powder collection container.

[0004] Patent CN1042321C discloses a method and apparatus for preparing uranium dioxide powder. After the reduction reaction is complete, a rotary valve is opened to discharge the UO2 powder into a stabilization bed. The powder is cooled by jacketed water. When cooled to 40°C, nitrogen containing air is introduced and stabilized for 20 minutes to produce ceramic-grade UO2 powder. The finished UO2 powder is then pumped into a mixing drum. The filter can be backflushed periodically during production. This patent does not address the issue of hydrogen and water vapor entering the post-processing system, nor does it provide a method for adjusting the oxygen-uranium ratio of the uranium dioxide.

[0005] Patent CN101254950A discloses a method for surface oxidation treatment of uranium dioxide powder, characterized by the following steps: 1) UO2 powder is placed in a tubular atmosphere furnace and heated in an oxidizing medium at a heating rate of 5-20°C / min to 250-400°C, maintaining the temperature for 2-6 hours; 2) after the UO2 powder has cooled to 100°C or room temperature in the furnace, it is removed and cooled in air to obtain uranium dioxide powder with an oxidized surface. Although this patent proposes a method for uranium dioxide oxidation treatment, it treats the powder in isolation, failing to achieve continuous post-processing of the uranium dioxide powder, and does not involve the removal of water vapor and hydrogen from the powder.

[0006] In view of the above technical problems, the present invention is specially introduced. Summary of the Invention

[0007] The main purpose of the present invention is to provide a uranium dioxide powder stabilization system, a post-processing system and a stabilization treatment method to prevent hydrogen and water vapor from entering the processing unit and adjust the oxygen-uranium ratio of the uranium dioxide powder.

[0008] To achieve the above-mentioned objectives, the present invention provides a uranium dioxide powder stabilization system, comprising a processing unit, a feeding unit, and a stabilization air intake unit, wherein the feeding unit is connected to the processing unit, through which uranium dioxide powder enters the processing unit, the stabilization air intake unit is connected to the processing unit, and the stabilization air intake unit introduces an oxygen-containing gas mixture into the processing unit to stabilize the uranium dioxide powder in the processing unit. The system also comprises an isolation unit, which is connected to the feeding unit, controls the opening and closing of the feeding unit, and prevents hydrogen and / or water vapor in the feeding unit from entering the processing unit when the feeding unit is closed.

[0009] Furthermore, the isolation unit includes a first valve body, and the first valve body is arranged on the feeding unit.

[0010] Furthermore, the isolation unit also includes an isolation gas pipeline, which is connected to the feed unit and introduces neutral gas into the side of the first valve body close to the processing unit, so that a pressure difference is formed on both sides of the first valve body close to and away from the processing unit.

[0011] Furthermore, the isolation unit further includes a second valve body, which is arranged in series with the first valve body in the feed unit and is located downstream of the feed of the first valve body.

[0012] Furthermore, the isolation gas pipeline is located on a branch of the feed unit where the first valve body and the second valve body are located.

[0013] Furthermore, the isolation unit also includes a filtering device, which is arranged in the isolation gas pipeline and filters the uranium dioxide powder flowing into the isolation gas pipeline.

[0014] Furthermore, it also includes a pretreatment air intake unit, which is connected to the feed end of the processing unit. The pretreatment air intake unit introduces neutral gas into the processing unit. The neutral gas enters the processing unit and then enters the feed unit, contacts the uranium dioxide powder in the feed unit, and removes water vapor and / or hydrogen in the uranium dioxide powder.

[0015] Furthermore, at the feeding end of the processing unit, the pressure of the gas introduced into the pre-treatment gas inlet unit is greater than the pressure in the feeding unit.

[0016] Furthermore, the neutral gas is turned back near the feed end of the processing unit, and comes into reverse contact with the material in the feed unit.

[0017] Furthermore, the stabilized air intake unit includes a first air intake pipeline and a second air intake pipeline, and the first air intake pipeline and the second air intake pipeline are connected to the processing unit to respectively introduce air and nitrogen into the processing unit.

[0018] Furthermore, flow regulators are provided on the first air inlet pipeline and the second air inlet pipeline, and the flow regulators control the air intake ratio of the first air inlet pipeline and the second air inlet pipeline to adjust the oxygen-uranium ratio and water content of the uranium dioxide powder.

[0019] Furthermore, the stabilized air intake unit also includes a heating device, one end of the heating device is connected to the first air intake pipeline and the second air intake pipeline, and the other end is connected to the processing unit.

[0020] Furthermore, the set temperature of the heating device is 60°C to 80°C.

[0021] Furthermore, the volume proportion of air in the oxygen-containing gas mixture is 1.5% to 3.5%.

[0022] Furthermore, it also includes an exhaust unit, which is connected to the feed end of the processing unit, and the gas in the processing unit is discharged through the exhaust unit.

[0023] Furthermore, a capture component is provided at the feed end of the processing unit, and the capture component filters the overflowed materials of the processing unit.

[0024] Furthermore, it also includes a back-blowing air pipeline, which introduces neutral gas into the capture component.

[0025] Furthermore, the processing unit is provided with a moisture monitor.

[0026] Furthermore, a thermometer and hygrometer is provided between the first valve body and the second valve body where the feeding unit is located.

[0027] The uranium dioxide powder stabilization system proposed in the present invention achieves the following technical effects:

[0028] 1. By setting up an isolation unit, hydrogen and water vapor in the preparation unit are prevented from entering the processing unit, the oxygen-uranium ratio in uranium dioxide is increased, and the quality of uranium dioxide powder is improved.

[0029] 2. By setting up a pre-treatment air intake unit, neutral gas is introduced at the inlet of the processing unit. The neutral gas enters the feeding unit and contacts the uranium dioxide powder in the feeding unit to remove water vapor and / or hydrogen in the uranium dioxide powder, further preventing water vapor and / or hydrogen in the uranium dioxide powder from entering the processing unit.

[0030] 3. By setting up two independent air inlet pipes, nitrogen and air are introduced respectively to dry and oxidize the uranium dioxide powder in the processing unit; and by setting up a flow regulator, it can meet the diverse needs of uranium dioxide powder with different oxygen-uranium ratios, thereby improving the flexibility, economy and safety of the production line.

[0031] 4. By setting a filter device in the isolation unit, the uranium dioxide powder flowing into the isolation gas pipeline is filtered to prevent the powder from entering the exhaust system, thereby improving the safety of the system.

[0032] On the other hand, the present application also proposes a uranium dioxide powder post-processing system, which includes multiple stabilization systems, which are arranged in parallel, and the processing units in the multiple stabilization systems are alternately fed and stabilized.

[0033] The uranium dioxide powder post-processing system proposed in the present invention achieves the following technical effects:

[0034] 1. By setting up multiple stabilization systems in parallel, the processing units are fed and stabilized alternately, which realizes continuous production and improves the operating efficiency of the system.

[0035] 2. The stabilization system used in the post-processing system prevents hydrogen and water vapor in the preparation unit from entering the processing unit by setting up an isolation unit, thereby increasing the oxygen-uranium ratio in uranium dioxide and improving the quality of uranium dioxide powder.

[0036] 3. The stabilization system used in the post-processing system is equipped with a pre-processing air intake unit. Neutral gas is introduced at the inlet of the processing unit. The neutral gas enters the feed unit and comes into contact with the uranium dioxide powder in the feed unit, removing water vapor and / or hydrogen in the uranium dioxide powder, further preventing water vapor and / or hydrogen in the uranium dioxide powder from entering the processing unit.

[0037] 4. The stabilization system used in the post-processing system is equipped with two independent air inlet pipes to introduce nitrogen and air respectively, so as to dry and oxidize the uranium dioxide powder in the processing unit. And by setting a flow regulator, it can meet the diverse needs of uranium dioxide powder with different oxygen-uranium ratios, thereby improving the flexibility, economy and safety of the production line.

[0038] 5. The stabilization system used in the post-processing system filters the uranium dioxide powder flowing into the isolation gas pipeline by setting a filter device in the isolation unit, preventing the powder from entering the exhaust system and improving the safety of the system.

[0039] On the other hand, the present application also proposes a method for stabilizing uranium dioxide powder, comprising: step S1, opening the isolation unit, and passing uranium dioxide powder into the processing unit through the feeding unit; step S2, closing the isolation unit, and stopping the feeding unit from passing uranium dioxide powder into the processing unit; step S3, opening the stabilization air inlet unit, and passing an oxygen-containing gas mixture into the processing unit.

[0040] Furthermore, step S1 includes step S11, opening the first valve body and the second valve body, and step S12, opening the pre-treatment air intake unit, introducing neutral gas into the processing unit, and then returning to enter the feeding unit.

[0041] Furthermore, step S2 includes: step S21, closing the first valve body and the second valve body; step S22, opening the isolation gas pipeline and introducing neutral gas.

[0042] Furthermore, step S3 includes: step S31, opening the first air inlet pipeline and the second air inlet pipeline to respectively introduce air and nitrogen into the processing unit; step S32, adjusting the flow regulator to adjust the ratio of the introduced air and nitrogen; and step S33, adjusting the heating device to heat the oxygen-containing gas mixture.

[0043] Furthermore, the method further includes step S4 of turning on the exhaust unit to discharge the gas in the processing unit through the exhaust unit.

[0044] Furthermore, the method further includes step S5 of opening a back-blowing gas pipeline to introduce neutral gas into the capture component.

[0045] The stabilization treatment method proposed in the present invention achieves the following technical effects:

[0046] 1. By controlling the opening and closing of the isolation unit, hydrogen and water vapor in the preparation unit are prevented from entering the processing unit, thereby increasing the oxygen-uranium ratio in uranium dioxide and improving the quality of uranium dioxide powder;

[0047] 2. By opening the pre-treatment air inlet unit, an oxygen-containing gas mixture is introduced into the processing unit (10) to contact the uranium dioxide powder in the feed unit, thereby removing water vapor and / or hydrogen in the uranium dioxide powder, thereby further preventing the water vapor and / or hydrogen in the uranium dioxide powder from entering the processing unit.

[0048] 3. By opening two independent air inlet pipes, nitrogen and air are introduced respectively to dry and oxidize the uranium dioxide powder in the processing unit; and by adjusting the flow regulator, it can meet the diverse needs of uranium dioxide powders with different oxygen-uranium ratios, thereby improving the flexibility, economy and safety of the production line.

[0049] 4. Open the back-blowing air pipe to introduce neutral gas into the capture component to avoid blockage of the capture component. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0051] Figure 1 A schematic diagram of the structure of a uranium dioxide powder stabilization system in an embodiment of the present application is shown;

[0052] Figure 2 The following is a schematic diagram of the structure of the uranium dioxide powder post-processing system in the embodiment of the present application;

[0053] Figure 3 The process of stabilizing uranium dioxide powder in one embodiment of the present application is shown. Figure 1 ;

[0054] Figure 4 The process of stabilizing uranium dioxide powder in one embodiment of the present application is shown. Figure 2 ;

[0055] Figure 5 The process of stabilizing uranium dioxide powder in one embodiment of the present application is shown. Figure 3 ;

[0056] Figure 6 The process of stabilizing uranium dioxide powder in one embodiment of the present application is shown. Figure 4 ;

[0057] Figure 7 The process of stabilizing uranium dioxide powder in one embodiment of the present application is shown. Figure 5 .

[0058] The above drawings include the following reference numerals:

[0059] 10. Processing unit; 20. Feeding unit; 30. Stabilized air intake unit; 40. Isolation unit; 42. First valve body; 44. Isolation gas pipeline; 48. Second valve body; 46. Filtering device; 50. Pretreatment air intake unit; 32. First air intake pipeline; 34. Second air intake pipeline; 33. Flow regulator; 36. Heating device; 70. Exhaust unit; 120. Capture component; 60. Back-blowing air pipeline; 140. Moisture monitor. DETAILED DESCRIPTION

[0060] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0061] The present invention is described in further detail below with reference to specific embodiments. These embodiments are not to be construed as limiting the scope of protection claimed by the present invention. The term "including" when used indicates the existence of a feature, but does not exclude the existence or addition of one or more other features; the terms "lateral", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be construed as limiting the present invention; in addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance.

[0062] In this description, it should be noted that, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention. Furthermore, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0063] Example 1:

[0064] In order to overcome the problem of hydrogen and water vapor entering the processing unit during the dry process, thereby reducing the oxygen-uranium ratio of uranium dioxide powder, this application optimizes the uranium dioxide stabilization system from three major aspects.

[0065] In a first aspect, the present application prevents hydrogen and water vapor from entering the processing unit by providing an isolation unit.

[0066] Specifically, as attached Figure 1 As shown, the uranium dioxide powder stabilization system includes a processing unit 10, a feeding unit 20, and a stabilization air intake unit 30. The feeding unit 20 is connected to the processing unit 10, through which the uranium dioxide powder enters the processing unit 10. The stabilization air intake unit 30 is connected to the processing unit 10 and introduces an oxygen-containing gas mixture into the processing unit 10 to stabilize the uranium dioxide powder in the processing unit 10.

[0067] The present application introduces an isolation unit 40 into the stabilization system. The isolation unit 40 is connected to the feed unit 20. The isolation unit 40 controls the opening and closing of the feed unit 20 and prevents hydrogen and / or water vapor in the feed unit 20 from entering the processing unit 10 in the closed state.

[0068] Specifically, the isolation unit 40 includes a first valve body 42, which is provided on the feeding unit 20. After the feeding is completed, the first valve body 42 is closed to prevent the hydrogen or water vapor in the feeding pipe from entering the processing unit. Furthermore, in order to improve the sealing performance, the present application also provides an isolation gas pipeline 44 in the isolation unit 40. The isolation gas pipeline 44 is connected to the feeding unit 20, and a neutral gas is introduced into the side of the first valve body 42 close to the processing unit 10, so that a pressure difference is formed on the two sides of the first valve body 42 close to and away from the processing unit 10. Preferably, the pressure of the first valve body 42 on the side close to the processing unit 10 is greater than the pressure on the side away from the processing unit 10, so that the hydrogen or water vapor on the side of the first valve body 42 away from the processing unit 10 is difficult to pass through the first valve body 42.

[0069] In addition, to further prevent hydrogen or water vapor from entering the processing unit, the present application also provides a second valve body 48, which is arranged in series with the first valve body 42 in the feed unit 20 and is located downstream of the feed of the first valve body 42. The isolation gas pipeline 44 is located on the branch of the feed unit 20 where the first valve body 42 and the second valve body 48 are located. Preferably, the second valve body 48 and the first valve body 42 used in the present application are pneumatic ball valves. In the present application, a thermometer and hygrometer are provided between the first valve body 42 and the second valve body 48 where the feed unit 20 is located.

[0070] Inevitably, a small amount of powder will be present between the first valve body 42 and the second valve body 48. The neutral gas introduced through the isolation gas line 44 can propel the powder into the exhaust system. To prevent radioactive powder from entering the exhaust system, the present application also includes a filter device 46 within the isolation unit 40. This filter device 46 is located within the isolation gas line 44 and filters the uranium dioxide powder flowing into the isolation gas line 44. The figures are for illustrative purposes only, and the number of filter devices 46 in this application is not specifically limited.

[0071] Secondly, the present application further prevents hydrogen and water vapor from entering the processing unit by providing a pre-treatment air intake unit.

[0072] Specifically, the pretreatment air intake unit 50 is connected to the feed end of the processing unit 10. During the feeding stage, the pretreatment air intake unit 50 introduces neutral gas into the processing unit 10. The neutral gas enters the processing unit 10 and then enters the feed unit 20, where it contacts the uranium dioxide powder in the feed unit 20 to remove water vapor and / or hydrogen from the uranium dioxide powder. The neutral gas is preferably nitrogen. In order to ensure that the introduced neutral gas smoothly enters the feed unit, in the present application, the gas pressure introduced by the pretreatment air intake unit 50 at the feed end of the processing unit 10 is greater than the pressure in the feed unit 20. The neutral gas is turned back near the feed end of the processing unit 10, forming reverse contact with the material in the feed unit 20, further preventing hydrogen and water vapor from entering the processing unit.

[0073] In addition, in the present application, a flow regulator is provided on the pipeline of the pretreatment air intake unit 50. When the thermometer and hygrometer between the first valve body (42) and the second valve body (48) shows that the humidity increases, it indicates that water vapor is flowing down. At this time, it is necessary to adjust the flow regulator provided on the pipeline of the pretreatment air intake unit 50 to increase the flow of neutral gas.

[0074] In a third aspect, the present application provides a stabilized air inlet unit to oxidize and dry the uranium dioxide powder in the processing unit, thereby increasing the oxygen-uranium ratio of the uranium dioxide powder.

[0075] Specifically, the stabilized air intake unit 30 includes a first air intake pipeline 32 and a second air intake pipeline 34. The first air intake pipeline 32 and the second air intake pipeline 34 are connected to the processing unit 10. After the feeding is completed, the first air intake pipeline 32 and the second air intake pipeline 34 respectively introduce air and nitrogen into the processing unit 10.

[0076] Preferably, flow regulators 33 are provided on the first and second air inlet lines 32, 34. These flow regulators 33 control the air intake ratio between the first and second air inlet lines 32, 34 to adjust the oxygen-uranium ratio and water content of the uranium dioxide powder, thereby meeting the diverse oxygen-uranium ratio requirements of actual uranium fuel elements. Preferably, the volume fraction of air in the oxygen-containing gas mixture is 1.5% to 3.5%, and compressed air is introduced into the first air inlet line 32.

[0077] Furthermore, the stabilized air intake unit 30 is equipped with a heating device 36. One end of the heating device 36 is connected to the first air intake line 32 and the second air intake line 34, and the other end is connected to the processing unit 10. The heating device 36 heats the incoming oxygen-containing gas mixture, further increasing the oxygen-uranium ratio. The preferred set temperature of the heating device 36 is 60°C to 80°C.

[0078] By optimizing the stabilization system from three aspects, hydrogen or water vapor in the feed unit is prevented from entering the processing unit, greatly improving the oxygen-uranium ratio of uranium dioxide powder and product quality.

[0079] In addition, the uranium dioxide powder stabilization system further includes an exhaust unit 70 , which is connected to the feed end of the processing unit 10 , and the gas in the processing unit 10 is discharged through the exhaust unit 70 .

[0080] The processing unit is equipped with a sampling device. After the sampling analysis is qualified, the pneumatic ball valve at the bottom of the processing unit is opened to discharge the qualified uranium dioxide powder to the next process.

[0081] In addition, the processing unit also includes a blasting device, which ruptures and shuts down the processing unit when the relative pressure in the processing unit exceeds a predetermined safety threshold. The safety threshold is set to 10KPa to 15KPa, preferably between 12KPa and 13KPa.

[0082] The processing unit also includes a weighing device for measuring the weight of the powder entering the processing unit. Preferably, a signal to stop feeding or an interlock is issued when a certain weight is reached during feeding; a signal to stop discharging or an interlock is issued when a certain weight is reached during discharging.

[0083] The processing unit 10 is provided with a moisture monitor 140 for online monitoring to obtain the moisture content of the powder and to sample the powder through a sampling valve.

[0084] A large amount of gas is introduced into the processing unit 10, and uranium dioxide powder may escape under the action of the gas. To prevent such an event from occurring, the present application provides a capture component 120 at the feed end of the processing unit 10. The capture component 120 filters the material overflowing from the processing unit 10. To prevent uranium dioxide powder from clogging the capture component 120, the present application also provides a back-blowing air duct 60, which passes neutral gas into the capture component 120, thereby periodically unclogging the capture component 120. Preferably, the processing unit in the present application is also provided with a pressure measuring device, which measures the relative pressure of the processing unit. When the relative pressure exceeds a predetermined value of the unclogging threshold, the back-blowing air duct 60 is opened. This unclogging threshold is lower than the safety threshold, and the difference between the two is within the range of 10KPa, and the preferred difference is less than 8KPa or 5KPa.

[0085] The uranium dioxide powder stabilization system proposed in the present invention achieves the following technical effects:

[0086] 1. By setting up an isolation unit, hydrogen and water vapor in the preparation unit are prevented from entering the processing unit, thereby increasing the oxygen-uranium ratio in uranium dioxide and improving the quality of uranium dioxide powder;

[0087] 2. By setting up a pre-treatment air intake unit, neutral gas is introduced at the inlet of the processing unit. The neutral gas enters the feeding unit and contacts the uranium dioxide powder in the feeding unit to remove water vapor and / or hydrogen in the uranium dioxide powder, further preventing water vapor and / or hydrogen in the uranium dioxide powder from entering the processing unit.

[0088] 3. By setting up two independent air inlet pipes, nitrogen and air are introduced respectively to dry and oxidize the uranium dioxide powder in the processing unit; and by setting up a flow regulator, it can meet the diverse needs of uranium dioxide powder with different oxygen-uranium ratios, thereby improving the flexibility, economy and safety of the production line.

[0089] 4. By setting a filter device in the isolation unit, the uranium dioxide powder flowing into the isolation gas pipeline is filtered to prevent the powder from entering the exhaust system, thereby improving the safety of the system.

[0090] Another aspect of the present application provides a uranium dioxide powder post-processing system, as shown in the attached Figure 2 As shown, the uranium dioxide powder reprocessing system includes multiple stabilization systems, which are arranged in parallel. The processing units 10 in the multiple stabilization systems alternately feed and stabilize to achieve continuous production. Specifically, when a processing unit in the previous stabilization system switches from a feeding state to a processing state, the isolation unit of the processing unit in the next stabilization system is opened to enter a receiving state. The isolation unit of the processing unit in the next stabilization system is closed to enter a processing state. The isolation unit of the processing unit in the previous stabilization system is opened, and the processing state switches from the processing state to the feeding state, thereby achieving continuous feeding and processing.

[0091] The uranium dioxide powder post-processing system proposed in this application achieves the following technical effects:

[0092] 1. By setting up multiple stabilization systems in parallel, the processing units are fed and stabilized alternately, which realizes continuous production and improves the operating efficiency of the system.

[0093] 2. The stabilization system used in the post-processing system prevents hydrogen and water vapor in the preparation unit from entering the processing unit by setting up an isolation unit, thereby increasing the oxygen-uranium ratio in uranium dioxide and improving the quality of uranium dioxide powder.

[0094] 3. The stabilization system used in the post-processing system is equipped with a pre-processing air intake unit. Neutral gas is introduced at the inlet of the processing unit. The neutral gas enters the feed unit and comes into contact with the uranium dioxide powder in the feed unit, removing water vapor and / or hydrogen in the uranium dioxide powder, further preventing water vapor and / or hydrogen in the uranium dioxide powder from entering the processing unit.

[0095] 4. The stabilization system used in the post-processing system is equipped with two independent air inlet pipes to introduce nitrogen and air respectively, so as to dry and oxidize the uranium dioxide powder in the processing unit. And by setting a flow regulator, it can meet the diverse needs of uranium dioxide powder with different oxygen-uranium ratios, thereby improving the flexibility, economy and safety of the production line.

[0096] 5. The stabilization system used in the post-processing system filters the uranium dioxide powder flowing into the isolation gas pipeline by setting a filter device in the isolation unit, preventing the powder from entering the exhaust system and improving the safety of the system.

[0097] In another aspect of the present application, a method for stabilizing uranium dioxide powder is proposed.

[0098] Specifically, combined with the Figure 3 and 7 As shown, the uranium dioxide powder stabilization method includes: step S1, opening the isolation unit 40, and allowing the feed unit 20 to pass uranium dioxide powder into the processing unit 10; step S2, closing the isolation unit 40, and stopping the feed unit 20 from passing uranium dioxide powder into the processing unit 10; step S3, opening the stabilized air inlet unit 30, and passing an oxygen-containing gas mixture into the processing unit 10; step S4, opening the exhaust unit 70, and exhausting the gas in the processing unit 10 through the exhaust unit 70; step S5, opening the backflush gas pipeline 60, and passing a neutral gas into the capture component 120. Closing the isolation unit prevents hydrogen and water vapor in the feed unit from entering the processing unit, and the uranium dioxide powder is oxidized by passing it into the stabilized air inlet unit, thereby increasing the oxygen-uranium ratio of the powder.

[0099] Preferably, Figure 4 As shown, step S1 includes step S11, opening the first valve body 42 and the second valve body 48; step S12, opening the pre-treatment air inlet unit 50, passing neutral gas into the processing unit 10, and then returning to enter the feeding unit 20. By passing the neutral gas during feeding, the neutral gas contacts the uranium dioxide powder in the feeding unit, thereby removing water vapor and / or hydrogen from the uranium dioxide powder.

[0100] Preferably, Figure 5 As shown, step S2 includes step S21, closing the first valve body 42 and the second valve body 48; and step S22, opening the isolation gas pipeline 44 to introduce neutral gas. By closing the two valve bodies and opening the isolation gas pipeline, hydrogen and water vapor in the feeding unit are prevented from entering the processing unit.

[0101] Preferably, Figure 6As shown, step S3 includes step S31, opening the first air inlet line 32 and the second air inlet line 34 to introduce air and nitrogen, respectively, into the processing unit 10; step S32, adjusting the flow regulator to adjust the ratio of the introduced air and nitrogen; and step S33, adjusting the heating device 36 to heat the oxygen-containing gas mixture. By adjusting the flow regulators, the air and nitrogen introduced into the first air inlet line 32 and the second air inlet line 34 are adjusted to meet the diverse oxygen-uranium ratio requirements of actual uranium fuel elements. Preferably, the volume proportion of air in the oxygen-containing gas mixture is 1.5% to 3.5%. Preferably, compressed air is introduced into the first air inlet line 32 in this application.

[0102] In addition, when the thermometer and hygrometer between the first valve body 42 and the second valve body 48 shows an increase in humidity, it indicates that water vapor is flowing down. At this time, it is necessary to adjust the flow regulator provided on the pipeline of the pre-treatment air intake unit 50 to increase the flow of neutral gas.

[0103] The following describes the post-processing system and stabilization method in detail based on a specific embodiment:

[0104] During the material collection stage, the first valve body 42 and the second valve body 48 on the feeding unit are first opened to discharge the material, and at the same time, the solenoid valve on the pre-treatment air intake unit is opened, and the neutral gas contacts the powder falling from the feeding unit 20 in countercurrent, so as to prevent the hydrogen and water vapor from the previous process from flowing into the post-processing unit 10 along with the powder; the processing unit 10 is equipped with a weighing device, and after the material is discharged to 50kg, it is stabilized, and at the same time, another set of processing devices enters the material collection stage. Close the first valve body 42 and the second valve body 48, and fill the space between the first valve body 42 and the second valve body 48 with 50 kPa of nitrogen to prevent hydrogen and water vapor from flowing downward into the processing unit 10. Turn on the heating device of the processing unit 10, then turn on the solenoid valves and the heating device 36 of the first air inlet line 32 and the second air inlet line 34 at the bottom of the processing unit 10, and adjust the ratio of the two gases through the flow regulator 33. The volume ratio of the compressed air introduced into the first air inlet line 32 is 2.7%, and the volume ratio of the nitrogen is 97.3%. The two gases are mixed and introduced into the bottom of the processing unit 10. One function of the mixed gas is to remove moisture from the powder, and the other function is to use the oxygen in the mixed gas to adjust the oxygen-uranium ratio of the uranium dioxide powder.

[0105] The moisture content of the powder is determined through the online moisture monitoring system built into processing unit 10. The powder is sampled using a sampling device. Once the sample passes the test, the valve below processing unit 10 can be opened to discharge the powder. In this application, the compressed air volume ratio is maintained at a uranium dioxide powder oxygen-uranium ratio between 2.02 and 2.18, ranging from 1.5% to 3.5%. The product oxygen-uranium ratio is positively correlated with the compressed air volume ratio.

[0106] The stabilization treatment method proposed in the present invention achieves the following technical effects:

[0107] 1. By controlling the opening and closing of the isolation unit, hydrogen and water vapor in the preparation unit are prevented from entering the processing unit, thereby increasing the oxygen-uranium ratio in uranium dioxide and improving the quality of uranium dioxide powder;

[0108] 2. By opening the pretreatment air inlet unit, an oxygen-containing gas mixture is introduced into the treatment unit to contact the uranium dioxide powder in the feed unit, thereby removing water vapor and / or hydrogen in the uranium dioxide powder, thereby further preventing water vapor and / or hydrogen in the uranium dioxide powder from entering the treatment unit.

[0109] 3. By opening two independent air inlet pipes, nitrogen and air are introduced respectively to dry and oxidize the uranium dioxide powder in the processing unit; and by adjusting the flow regulator, it can meet the diverse needs of uranium dioxide powders with different oxygen-uranium ratios, thereby improving the flexibility, economy and safety of the production line.

[0110] 4. Open the back-blowing air pipe to introduce neutral gas into the capture component to avoid blockage of the capture component.

[0111] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A uranium dioxide powder stabilization system (1), comprising a processing unit (10), a feeding unit (20), a stabilization air inlet unit (30), The feeding unit (20) is connected to the processing unit (10), and the uranium dioxide powder enters the processing unit (10) through the feeding unit (20). The stabilized air inlet unit (30) is connected to the processing unit (10), and the stabilized air inlet unit (30) introduces an oxygen-containing gas mixture into the processing unit (10) to perform a stabilization treatment on the uranium dioxide powder in the processing unit (10). It is characterized in that The device further comprises an isolation unit (40), the isolation unit (40) being connected to the feed unit (20), the isolation unit (40) controlling the opening and closing of the feed unit (20), and preventing hydrogen and / or water vapor in the feed unit (20) from entering the processing unit (10) in a closed state; The invention also includes a pretreatment air intake unit (50), wherein the pretreatment air intake unit (50) is connected to the feed end of the processing unit (10), and the pretreatment air intake unit (50) introduces neutral gas into the processing unit (10). The neutral gas enters the processing unit (10) and then enters the feed unit (20), contacts the uranium dioxide powder in the feed unit (20), and removes water vapor and / or hydrogen in the uranium dioxide powder.

2. The uranium dioxide powder stabilization system (1) according to claim 1, characterized in that: The isolation unit (40) comprises a first valve body (42), and the first valve body (42) is arranged on the feeding unit (20).

3. The uranium dioxide powder stabilization system according to claim 2, characterized in that: The isolation unit (40) further includes an isolation gas pipeline (44), which is connected to the feed unit (20) and introduces neutral gas into the side of the first valve body (42) close to the processing unit (10), so that a pressure difference is formed on both sides of the first valve body (42) close to and away from the processing unit (10).

4. The uranium dioxide powder stabilization system (1) according to claim 3, characterized in that: The isolation unit (40) further includes a second valve body (48), which is arranged in series with the first valve body (42) in the feed unit (20) and is located downstream of the feed of the first valve body (42).

5. The uranium dioxide powder stabilization system (1) according to claim 4, characterized in that: The isolation gas pipeline (44) is located on a branch of the feed unit (20) where the first valve body (42) and the second valve body (48) are located.

6. The uranium dioxide powder stabilization system (1) according to claim 5, characterized in that: The isolation unit (40) further includes a filtering device (46), wherein the filtering device (46) is arranged in the isolation gas pipeline (44), and the filtering device (46) filters the uranium dioxide powder flowing into the isolation gas pipeline (44).

7. The uranium dioxide powder stabilization system according to claim 1, characterized in that: At the feeding end of the processing unit (10), the pressure of the gas introduced into the pre-treatment gas inlet unit (50) is greater than the pressure in the feeding unit (20).

8. The uranium dioxide powder stabilization system (1) according to claim 7, characterized in that: The neutral gas is turned back near the feed end of the processing unit (10), and forms reverse contact with the material in the feed unit (20).

9. The uranium dioxide powder stabilization system according to any one of claims 1 to 6, characterized in that: The stabilized air intake unit (30) comprises a first air intake pipeline (32) and a second air intake pipeline (34), and the first air intake pipeline (32) and the second air intake pipeline (34) are connected to the processing unit (10) to respectively introduce air and nitrogen into the processing unit (10).

10. The uranium dioxide powder stabilization system (1) according to claim 9, characterized in that: The first air inlet line (32) and the second air inlet line (34) are provided with flow regulators (33), and the flow regulators (33) control the air intake ratio of the first air inlet line (32) and the second air inlet line (34) to adjust the oxygen-uranium ratio and water content of the uranium dioxide powder.

11. The uranium dioxide powder stabilization system (1) according to claim 10, characterized in that: The stabilized air intake unit (30) further comprises a heating device (36), one end of the heating device (36) being connected to the first air intake pipeline (32) and the second air intake pipeline (34), and the other end being connected to the processing unit (10).

12. The uranium dioxide powder stabilization system (1) according to claim 11, characterized in that: The set temperature of the heating device (36) is 60-80°C.

13. The uranium dioxide powder stabilization system (1) according to any one of claims 1 to 6, characterized in that: The volume proportion of air in the oxygen-containing gas mixture is 1.5% to 3.5%.

14. The uranium dioxide powder stabilization system (1) according to any one of claims 1 to 6, characterized in that: It also includes an exhaust unit (70), the exhaust unit (70) being connected to the feed end of the processing unit (10), and the gas in the processing unit (10) being discharged through the exhaust unit (70).

15. The uranium dioxide powder stabilization system (1) according to any one of claims 1 to 6, characterized in that: A capture component (120) is provided at the feed end of the processing unit (10), and the capture component (120) filters overflowing substances from the processing unit (10).

16. The uranium dioxide powder stabilization system (1) according to claim 15, characterized in that It also includes a back-blowing gas pipeline (60), wherein the back-blowing gas pipeline (60) introduces neutral gas into the capture component (120).

17. The uranium dioxide powder stabilization system (1) according to any one of claims 1 to 6, characterized in that: The processing unit (10) is provided with a moisture monitor (140).

18. The uranium dioxide powder stabilization system (1) according to claim 5 or 6, characterized in that: A thermometer and hygrometer is provided between the first valve body (42) and the second valve body (48) where the feeding unit (20) is located.

19. A uranium dioxide powder post-processing system, characterized in that: The invention comprises a plurality of stabilization systems (1) according to any one of claims 1 to 18, wherein the plurality of stabilization systems (1) are arranged in parallel, and the processing units (10) in the plurality of stabilization systems (1) are alternately fed and stabilized.

20. A method for stabilizing uranium dioxide powder, using the uranium dioxide powder stabilization system according to any one of claims 1 to 18, characterized in that: include: Step S1: opening the isolation unit (40), and introducing the uranium dioxide powder into the processing unit (10) through the feeding unit (20). Step S2, closing the isolation unit (40), and stopping the feeding unit (20) from feeding the uranium dioxide powder into the processing unit (10). Step S3: Open the stabilized air inlet unit (30) to introduce the oxygen-containing gas mixture into the processing unit (10).

21. The method for stabilizing uranium dioxide powder according to claim 20, characterized in that: Step S1 includes, Step S11, open the first valve body (42) and the second valve body (48), Step S12, opening the pre-treatment air intake unit (50), introducing neutral gas into the treatment unit (10), and then returning to enter the feeding unit (20).

22. The method for stabilizing uranium dioxide powder according to claim 21, characterized in that: Step S2 includes, Step S21, closing the first valve body (42) and the second valve body (48), Step S22, opening the isolation gas pipeline (44) and introducing the neutral gas.

23. The method for stabilizing uranium dioxide powder according to claim 22, characterized in that: Step S3 includes, Step S31, opening the first air inlet line (32) and the second air inlet line (34), and introducing air and nitrogen into the processing unit (10) respectively, Step S32: Adjust the flow regulator to adjust the ratio of air and nitrogen. Step S33, adjusting the heating device (36) to heat the oxygen-containing gas mixture.

24. The method for stabilizing uranium dioxide powder according to claim 23, characterized in that: Also includes, Step S4: opening the exhaust unit (70) to exhaust the gas in the processing unit (10) through the exhaust unit (70).

25. The method for stabilizing uranium dioxide powder according to claim 24, characterized in that: Also includes, Step S5: Open the back-blowing gas pipeline (60) to introduce neutral gas into the capture component (120).

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