Apparatus and method for measuring aerosol release fraction and rate at a breach of a lead-bismuth fuel stack

Abstract

The application discloses a device and method for measuring aerosol release share and rate at a fuel rod break of a lead-bismuth reactor, which comprises a high-pressure gas tank, an aerosol mixing device, a simulated fuel rod, a break sealing device, a collecting device, a particle size spectrometer and pipeline valves and flow pressure measuring instruments. The high-pressure gas tank is used for providing required gas, the aerosol mixing device is used for mixing gas and used aerosol powder, the simulated fuel rod is used for containing high-pressure aerosol and is designed in different shapes and sizes of cladding breaks according to the size and structure of a real lead-bismuth reactor fuel rod, the break sealing device is used for sealing the break to form a closed environment inside the fuel rod, the collecting device is used as a containing place of the aerosol to facilitate subsequent sampling measurement, and the particle size spectrometer is used for measuring the aerosol particle concentration of sample gas. The application can complete the measurement of the aerosol release share in the gap between the fuel rod pellet and the cladding and the release rate of the gas through the break, and is used for studying the release characteristics of the aerosol and the fissile gas under different fissile gas pressures and different break sizes and appearances.

Description

Technical Field

[0001] The present invention belongs to the technical field of research on the release mechanism of fission products, and in particular relates to a device and method for measuring the aerosol release fraction and rate at a lead-bismuth pile fuel rupture. Background Art

[0002] During reactor operation, the fission process in the core fuel assemblies produces a large amount of radioactive fission products. However, fretting erosion, foreign body abrasion, chemical corrosion, irradiation creep and swelling, and the high pressure of fission products within the fuel cladding can cause the fuel cladding to rupture, releasing fission products into the coolant. In addition to the common fission gases, the fission products released from the rupture also include non-gaseous fission products such as solid and liquid fission products. In computational programs, both liquid and solid fission products are typically simulated using aerosol particles. Current mechanistic source term analyses for lead-bismuth (Bismuth) reactors use an assumed value for the aerosol fraction released from the rupture, introducing uncertainty into the source term calculations. Therefore, experimental studies of the complex physical process of fission product release from fuel elements into the liquid lead-bismuth alloy coolant in lead-bismuth fast reactors are urgently needed to determine key parameters of the fission product migration process, such as the gas release rate and the total aerosol fraction released after the release, to support model development and source term analysis. Summary of the Invention

[0003] To solve the above problems, the purpose of the present invention is to provide a device and method for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel, which can be used to study the release characteristics of aerosol and fission gas under different fission gas pressures and different rupture sizes and morphologies.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A device for measuring the aerosol release fraction and rate at a lead-bismuth fuel breach, comprising a high-pressure gas tank 1, an aerosol mixing device 2, a simulated fuel rod 3, a breach sealing device 4, a collecting device 5, a particle size spectrometer 6, a pipeline valve, and a flow and pressure measuring instrument;

[0006] The high-pressure gas tank 1 is used to provide the gas required by the entire device, is arranged at the front end of the device, and is connected to the aerosol mixing device 2 through a ventilation pipe;

[0007] The aerosol mixing device 2 is used to uniformly mix the gas and the aerosol powder used, and provide aerosol of a specified concentration to the simulated fuel rod 3. It is arranged near the front gas inlet of the simulated fuel rod 3 and connected to the simulated fuel rod 3 through a ventilation pipe to ensure that the aerosol enters quickly after mixing and reduce pipeline residue;

[0008] The simulated fuel rods 3 are used to contain high-pressure aerosols and have holes of different shapes and sizes constructed on the fuel rod cladding. The design is based on the size and structure of real lead-bismuth reactor fuel rods. The front gas enters the simulated fuel rods 3 through the high-pressure gas tank 1 and the aerosol mixing device 2 in sequence.

[0009] The breach sealing device 4 has the function of sealing the breach of the simulated fuel rod, and can construct a closed internal space of the simulated fuel rod to carry high-pressure gas. It is arranged on the simulated fuel rod 3 as a gas outlet, and the rear end is connected to the collection device 5;

[0010] The collecting device 5 serves as a place to hold the aerosol released from the simulated fuel rods, facilitating subsequent sampling and measurement. It is located at the end of the gas flow path and a gas measurement pipeline is led out from it to connect to the particle size spectrometer 6.

[0011] The particle size spectrometer 6 is used to measure the aerosol particle concentration of the sample gas, and collects the measured gas from the collection device 5.

[0012] The high-pressure gas tank 1 is composed of multiple gas tanks to provide sufficient gas to the aerosol mixing device 2. The high-pressure gas tank is connected to the aerosol injection section of the aerosol mixing device 2 through a gas tank pressure regulating valve 7 to adjust the upper end pressure of the aerosol injection section.

[0013] The gas in the high-pressure gas tank 1 is helium.

[0014] The main body of the aerosol mixing device 2 is composed of a mixing device shell 2-2 and a rotating screw 2-1 located in the shell 2-2. The mixing device shell 2-2 is provided with a mixing device gas inlet 2-3 and a mixing device aerosol outlet 2-4. The motor 2-5 provides power to drive the rotating screw rotating shaft 2-6 to rotate, thereby rotating the rotating screw 2-1. Aerosol powder 2-7 is arranged at the bottom of the mixing device shell 2-2. The rotation of the rotating screw 2-1 drives the aerosol powder 2-7 to move upward and mix with the incoming gas to form an aerosol.

[0015] The aerosol powder 2-7 is titanium dioxide powder.

[0016] The simulated fuel rod 3 consists of an upper end plug 3-1, a fuel rod cladding 3-2, and an internal pellet unit. The upper end plug 3-1 and the fuel rod cladding 3-2 are threadedly connected to form the fuel rod as a whole, wherein the pellet unit is composed of a spring 3-3 and a pellet 3-4 connected to each other. The dimensions of each part of the simulated fuel rod 3 are designed with reference to the dimensions of a real lead-bismuth fast reactor fuel rod; a fuel rod pressure gauge 3-8 is placed at the upper end plug 3-1 to measure the gas pressure inside the simulated fuel rod, and a rupture 3-5, a gas injection port 3-6, and a sampling port 3-7 are designed on the fuel rod cladding 3-2, which are respectively used to release high-pressure gas, inject high-pressure gas into the simulated fuel rod, and sample and measure the high-pressure gas.

[0017] The breach sealing device 4 includes two sealing devices relatively arranged on the simulated fuel rod 3, each sealing device includes a pressure cap 4-1 and a pressure rod 4-2, and the two pressure caps 4-1 are butted together. The internal structure of the pressure cap 4-1 is consistent with the shape of the fuel rod cladding and is smooth to ensure that it can fit the fuel rod cladding and thus ensure its sealing. When sealing the breach, a force along the radial direction of the simulated fuel rod is applied to the pressure rods 4-2 of the two sealing devices so that the two sealing devices can close the breach while maintaining the balance of force on the fuel rod. When opening the breach, the radial force is removed and the breach sealing device 4 is moved to expose the breach.

[0018] The collecting device shell 5-1 of the collecting device 5 is integrated with the fuel rod cladding 3-2, serving as a place to contain aerosols released from the simulated fuel rods and facilitating sampling and measurement. Samples are drawn through a sampling tube 5-2 provided on the collecting device shell 5-1.

[0019] The particle size spectrometer 6 includes a scanning mobility particle size spectrometer 6-1 and a pre-measurement channel 6-2 directly connected to the scanning mobility particle size spectrometer 6-1, an in-cladding measurement channel 6-4, a collection device measurement channel 6-6, and a residual gas cleaning channel 6-9; the pre-measurement channel 6-2 is provided with a pre-measurement channel valve 6-3, the in-cladding measurement channel 6-4 is provided with an in-cladding measurement channel valve 6-5, the collection device measurement channel 6-6 is provided with a collection device measurement channel valve 6-7, and the residual gas cleaning channel 6-9 is provided with a residual gas cleaning channel valve 6-8.

[0020] Technical problems and advantages solved by the present invention:

[0021] Technical problems solved by the present invention:

[0022] 1) The device described in the present invention solves the problem of measuring the release fraction and rate of fission products after damage to lead-bismuth fuel;

[0023] 2) The device described in the present invention solves the problem of difficulty in restoring the structural dimensions of real lead-bismuth stack fuel rods in experiments.

[0024] The present invention has the following advantages and beneficial effects:

[0025] 1) The device of the present invention adopts the structure and size of the actual lead-bismuth reactor fuel rod, which is as close to the actual reactor as possible, laying the foundation for the authenticity and reliability of the experimental data.

[0026] 2) The gas and aerosol powder of the present invention respectively use helium and titanium dioxide powder, which are non-polluting and harmless to the environment and human body, and can therefore be directly discharged into the environment, greatly simplifying the waste collection process of the experiment.

[0027] 3) Due to its special gas supply method (gas supply from high-pressure gas cylinders), the device of the present invention can increase or decrease the number of gas cylinders according to demand to meet the time requirements for steady-state experiments.

[0028] 4) The device of the present invention has a simple structure, is easy to process and disassemble, and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0030] Figure 1 Schematic diagram of the device for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel in the present invention.

[0031] Figure 2 Schematic diagram of the structure of the aerosol mixing device of the present invention.

[0032] Figure 3 This is a schematic diagram of the simulated fuel rod structure of the present invention.

[0033] Figure 4 Schematic diagram of the appearance of the breach sealing device of the present invention.

[0034] Figure 5 This is a schematic diagram of the appearance of the collecting device of the present invention.

[0035] Figure 6 Schematic diagram of the appearance of the measurement system of the present invention.

[0036] 1- High-pressure gas tank, 2- Aerosol mixing device, 2-1- Rotating screw, 2-2- Mixing device housing, 2-3- Gas inlet, 2-4- Mixing device aerosol outlet, 2-5- Motor, 2-6- Rotating screw rotating shaft, 2-7- Aerosol powder, 3- Simulated fuel rod, 3-1- Upper end plug, 3-2- Fuel rod cladding, 3-3- Spring, 3-4- Pellets (containing a cavity at the bottom), 3-5- Rupture, 3-6- Gas injection port, 3-7- Sampling port, 3-8- Fuel rod pressure gauge, 4- Rupture sealing device, 4-1- Pressure cap, 4-2-pressure rod, 5-collecting device, 5-1-collecting device housing, 5-2-sampling tube, 6-particle size spectrometer, 6-1-scanning mobility particle size spectrometer, 6-2-pre-measurement channel, 6-3-pre-measurement channel valve, 6-4-measuring channel inside the cladding, 6-5-measuring channel valve inside the cladding, 6-6-collecting device measurement channel, 6-7-collecting device measurement channel valve, 6-8-residual gas cleaning channel valve, 6-9-residual gas cleaning channel, 7-gas tank pressure regulating valve, 8-stable bypass pressure regulating valve, 9-fuel rod sampling pressure regulating valve. DETAILED DESCRIPTION

[0037] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0038] like Figure 1 As shown, the present invention provides a device for measuring the aerosol release fraction and rate at the rupture of a lead-bismuth pile fuel, the device comprising a high-pressure gas tank 1, an aerosol mixing device 2, a simulated fuel rod 3, a rupture sealing device 4, a collecting device 5, a particle size spectrometer 6, and measuring instruments such as pipeline valves and flow pressure.

[0039] The high-pressure gas tank 1 is used to provide the gas required by the entire device. It is located at the front end of the device and is connected to the aerosol mixing device 2 through a ventilation pipe with good airtightness.

[0040] The aerosol mixing device 2 is used to uniformly mix the gas and the aerosol powder used, and provide aerosol of a specified concentration to the simulated fuel rod. It is located near the front gas inlet of the simulated fuel rod 3 and is connected to the simulated fuel rod 3 through a well-sealed ventilation pipe to ensure that the aerosol enters quickly after mixing and reduce pipe residue.

[0041] The simulated fuel rod 3 is used to contain high-pressure aerosol and has holes of different shapes and sizes constructed on the cladding. It is designed with reference to the size and structure of real lead-bismuth pile fuel rods and is placed at the center of the device. The front gas enters the device through the high-pressure gas tank 1 and the aerosol mixing device 2 in sequence.

[0042] The breakage closure device 4 has the function of closing the breakage of the fuel rod, and can construct a closed simulation fuel rod internal space to bear high pressure gas, and is arranged on the simulation fuel rod 3 as a gas outlet, and the rear end is connected to the collection device 5;

[0043] The collection device 5 is a containing place of the aerosol released through the fuel rod, and facilitates subsequent sampling and measurement, and is arranged at the last end of the gas flow path, and a gas sampling pipe is connected to the particle size spectrometer 6 to guide the gas outwards;

[0044] The particle size spectrometer 6 is used for measuring the aerosol particle concentration of the sample gas, and the measured gas is collected from the collection device 5.

[0045] Preferably, the high-pressure gas tank 1 of the present application can be composed of multiple gas tanks to provide sufficient gas to the device, and the high-pressure gas tank is connected to the aerosol injection section of the aerosol mixing device 2 through a gas tank pressure regulating valve 7 to adjust the pressure at the upper end of the aerosol injection section. More preferably, the gas in the high-pressure gas tank 1 is helium.

[0046] Preferably, as shown in Figure 2 The aerosol mixing device 2 of the present application is composed of a mixing device shell 2-2 and a rotating screw 2-1 located in the shell 2-2, and the mixing device shell 2-2 is provided with a mixing device gas inlet 2-3 and a mixing device aerosol outlet 2-4, and a rotating screw rotating shaft 2-6 is driven to rotate by a motor 2-5 to rotate the rotating screw 2-1, and the bottom of the mixing device shell 2-2 is arranged with aerosol powder 2-7, which is driven to move upwards by the rotating screw 2-1 to mix with the incoming gas to form aerosol. More preferably, the aerosol powder 2-7 is titanium dioxide powder.

[0047] Preferably, as shown in Figure 3 The simulation fuel rod 3 of the present application is composed of an upper end plug 3-1, a fuel rod cladding 3-2 and an internal pellet unit, the upper end plug 3-1 and the fuel rod cladding 3-2 are connected by threads to form the whole fuel rod, and the pellet unit is composed of a spring 3-3 and a pellet 3-4 (the lower part contains a cavity), and the dimensions of each part of the simulation fuel rod 3 are designed in reference to the dimensions of the real lead-bismuth fast reactor fuel rod. At the same time, a fuel rod pressure gauge (3-8) is placed at the upper end plug 3-1 to measure the internal gas pressure of the simulation fuel rod, and a breakage 3-5, a gas injection port 3-6 and a sampling port 3-7 are designed on the fuel rod cladding 3-2 for releasing high pressure gas, injecting high pressure gas into the simulation fuel rod and sampling and measuring the high pressure gas, respectively.

[0048] Preferably, as shown in Figure 4As shown, the breach sealing device 4 of the present invention includes two sealing devices arranged relative to each other on the simulated fuel rod 3. Each sealing device is composed of a pressure cap 4-1 and a pressure rod 4-2. The two pressure caps 4-1 are butted together. The internal structure of the pressure cap 4-1 is consistent with the shape of the fuel rod cladding and is sufficiently smooth to ensure that it can fit the fuel rod cladding and thus ensure its sealing. When sealing the breach, a force along the radial direction of the fuel rod is applied to the pressure rods 4-2 of the two sealing devices so that the two sealing devices can close the breach while maintaining the balance of force on the fuel rod. When opening the breach, the radial force is removed and the sealing devices are moved to expose the breach.

[0049] Preferably, Figure 5 As shown, the collecting device shell 5-1 of the collecting device 5 of the present invention is integrated with the fuel rod cladding 3-2, serving as a place to contain aerosols released from the fuel rods and facilitating sampling and measurement, and the sample is sucked through the sampling tube 5-3.

[0050] Preferably, Figure 6 As shown, the particle size spectrometer 6 of the present invention includes a scanning mobility particle size spectrometer 6-1 and a pre-measurement channel 6-2 directly connected to the scanning mobility particle size spectrometer 6-1, an in-cladding measurement channel 6-4, a collecting device measurement channel 6-6, and a residual gas cleaning channel 6-9; the pre-measurement channel 6-2 is provided with a pre-measurement channel valve 6-3, the in-cladding measurement channel 6-4 is provided with an in-cladding measurement channel valve 6-5, the collecting device measurement channel 6-6 is provided with a collecting device measurement channel valve 6-7, and the residual gas cleaning channel 6-9 is provided with a residual gas cleaning channel valve 6-8. Example

[0051] Before starting use, assemble the entire device and check to ensure that all systems are working properly, all connections are well sealed, there is no obvious damage or leakage, and the gas supply meets the experimental needs.

[0052] After the entire device is assembled, apply a tightening force to the breach sealing device 4 to seal the breach 4-3 of the simulated fuel rod. Open the corresponding valve of the gas bypass in the aerosol injection section and inject gas into the simulated fuel rod 3. Observe the pressure gauge 3-8 until the pressure reaches the specified working condition and terminate the gas injection. Allow sufficient time to stand and continue observing the reading on the pressure gauge 3-8. If the reading drops significantly, the simulated fuel rod needs to be reassembled and sealed. If the reading is basically stable at the set working condition, the simulated fuel rod is airtight and meets the requirements of subsequent experiments.

[0053] A certain amount of aerosol powder 2-7 is placed into the aerosol mixing device 2 and the device motor 2-5 is turned on. After the rotating screw 2-1 transports the powder stably, the high-pressure gas tank 1 and the gas tank pressure regulating valve 7 are opened to inject gas into the mixing device 2 at a specified pressure. At this time, the stabilizing bypass pressure regulating valve 8 is opened to discharge the aerosol outward through the aerosol stabilizing bypass. After a certain period of time, the pre-measurement channel valve 6-3 is opened to absorb the aerosol in the aerosol stabilizing bypass through the measuring channel 6-2 to measure the aerosol concentration at different times. After the aerosol concentration is stable, the stabilizing bypass pressure regulating valve 8 is closed to connect the injection section to the simulated fuel rod, and the aerosol is injected into the simulated fuel rod 3 to the specified pressure.

[0054] After the aerosol injection is completed, the entire device is left to stand for a sufficient period of time to ensure that the aerosol in the simulated fuel rod can be fully deposited. The pressure regulating valve 9 on the simulated fuel rod 3 is opened, and a small amount of gas in the simulated fuel rod 3 is discharged through the sampling port 3-7. After that, the fuel rod sampling pressure regulating valve 9 is closed, and the particle size spectrometer 6 is turned on to draw a small amount of sample through the measurement channel 6-4 in the cladding for measurement.

[0055] The breach 4-3 is opened by the breach sealing device 4, and the gas begins to be released. When the fuel rod pressure gauge 3-8 shows a substantially stable atmospheric pressure, the gas release is completed, and the particle size spectrometer 6 is turned on to absorb a certain amount of sample gas in the collecting device 5 through the collecting device measurement channel 6-6 for measurement.

[0056] Clean the aerosol in the collection device 5, open the gas bypass to purge the entire device, record and organize the experimental data, and obtain the change pattern of the aerosol release ratio. According to the different working conditions set, change the working conditions and conduct the experiment according to the same method. Example

[0057] Before starting use, assemble the entire device and check to ensure that all systems are working properly, all connections are well sealed, there is no obvious damage or leakage, and the gas supply meets the experimental needs.

[0058] After the entire apparatus is assembled, apply a tightening force to the breach sealing device 4 to seal the breach 3-5 of the simulated fuel rod. Open the corresponding valve of the gas bypass in the aerosol injection section and inject gas into the simulated fuel rod 3. Observe the fuel rod pressure gauge 3-8 until the pressure reaches the specified operating pressure, then terminate the gas injection. Allow sufficient time for the pressure gauge to stand and continue observing the reading on the fuel rod pressure gauge 3-8. If the reading decreases significantly, reseal the simulated fuel rod. If the reading remains stable at the set operating pressure, the simulated fuel rod is airtight and meets the requirements of subsequent experiments.

[0059] Start the gas bypass of the aerosol injection section, inject gas into the simulated fuel rod 3 until the fuel rod pressure gauge 3-8 shows the specified operating pressure, and then close the aerosol injection section.

[0060] Adjust the outlet pressure of the gas tank pressure regulating valve 7 to the preset pressure, reopen the aerosol injection section, and simultaneously operate the breach sealing device 4 to open the breach. Once the fuel rod pressure gauge 3-8 stabilizes at the set operating value, adjust the injection pressure of the gas tank pressure regulating valve 7 to ensure that the fuel rod pressure gauge 3-8 remains constant. The flow meter reading of the aerosol injection section represents the flow rate at breach 3-5. After the designated injection time, close the aerosol injection section, and the experiment concludes.

[0061] Clean and organize the entire device, record and organize the experimental data, and obtain the variation pattern of the gas release rate. According to the different working conditions set, change the working conditions and use the same method to explore the effect of different internal pressures and rupture sizes on the gas release rate.

[0062] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for measuring the aerosol release fraction and rate at a lead-bismuth fuel breach, characterized by: The device comprises a high-pressure gas tank (1), an aerosol mixing device (2), a simulated fuel rod (3), a breach sealing device (4), a collecting device (5), a particle size spectrometer (6), a pipeline valve, and a flow and pressure measuring instrument; The high-pressure gas tank (1) is used to provide the gas required by the entire device, is arranged at the front end of the device, and is connected to the aerosol mixing device (2) through a ventilation pipe; The aerosol mixing device (2) is used to uniformly mix the gas and the aerosol powder used, and provide aerosol of a specified concentration to the simulated fuel rod (3). It is arranged near the front gas inlet of the simulated fuel rod (3) and is connected to the simulated fuel rod (3) through a ventilation pipe to ensure that the aerosol enters quickly after mixing and reduce pipeline residue. The simulated fuel rod (3) is used to contain high-pressure aerosol and to construct ruptures of different shapes and sizes on the fuel rod cladding. The front end gas enters the simulated fuel rod (3) through the high-pressure gas tank (1) and the aerosol mixing device (2) in sequence; The breach sealing device (4) has the function of sealing the breach of the simulated fuel rod, can construct a closed internal space of the simulated fuel rod to carry high-pressure gas, is arranged on the simulated fuel rod (3) as a gas outlet, and is connected to the collection device (5) at the rear end; The collecting device (5) serves as a place to hold the aerosol released from the simulated fuel rod, facilitating subsequent sampling and measurement. The collecting device (5) is located at the rear end of the gas flow path, and a gas measurement pipeline is led out from the inside to connect to the particle size spectrometer (6); The particle size spectrometer (6) is used to measure the aerosol particle concentration of the sample gas, and collects the measured gas from the collection device (5).

2. The device for measuring the aerosol release fraction and rate at the lead-bismuth pile fuel breach according to claim 1, characterized in that: The high-pressure gas tank (1) is composed of a plurality of gas tanks to provide a sufficient amount of gas to the aerosol mixing device (2). The high-pressure gas tank is connected to the aerosol injection section of the aerosol mixing device (2) via a gas tank pressure regulating valve (7) to adjust the upper end pressure of the aerosol injection section.

3. The device for measuring the aerosol release fraction and rate at the lead-bismuth pile fuel breach according to claim 2, characterized in that: The gas in the high-pressure gas tank (1) is helium.

4. The device for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel according to claim 1, characterized in that: The main body of the aerosol mixing device (2) is composed of a mixing device housing (2-2) and a rotating screw (2-1) located in the housing (2-2); a mixing device gas inlet (2-3) and a mixing device aerosol outlet (2-4) are provided on the mixing device housing (2-2); a motor (2-5) provides power to drive a rotating screw shaft (2-6) to rotate, thereby rotating the rotating screw (2-1); aerosol powder (2-7) is arranged at the bottom of the mixing device housing (2-2); the rotating screw (2-1) rotates to drive the aerosol powder (2-7) to move upward, thereby mixing with the incoming gas to form an aerosol.

5. The device for measuring the aerosol release fraction and rate at the lead-bismuth pile fuel breach according to claim 4, characterized in that: The aerosol powder (2-7) is titanium dioxide powder.

6. The device for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel according to claim 1, characterized in that: The simulated fuel rod (3) is composed of an upper end plug (3-1), a fuel rod cladding (3-2) and an internal pellet unit. The upper end plug (3-1) and the fuel rod cladding (3-2) are connected by threads to form a fuel rod as a whole. The pellet unit is composed of a spring (3-3) and a pellet (3-4) connected to each other. The dimensions of each part of the simulated fuel rod (3) are designed with reference to the dimensions of a real lead-bismuth fast reactor fuel rod. A fuel rod pressure gauge (3-8) is placed at the upper end plug (3-1) to measure the internal gas pressure of the simulated fuel rod. A rupture (3-5), a gas injection port (3-6) and a sampling port (3-7) are designed on the fuel rod cladding (3-2), which are respectively used to release high-pressure gas, inject high-pressure gas into the simulated fuel rod and sample and measure the high-pressure gas.

7. The device for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel according to claim 1, characterized in that: The breach closing device (4) comprises two sealing devices arranged relatively on the simulated fuel rod (3), each sealing device comprising a pressure cap (4-1) and a pressure rod (4-2), the two pressure caps (4-1) being butt-jointed, the internal structure of the pressure cap (4-1) being consistent with the shape of the fuel rod cladding and being smooth to ensure that it can fit the fuel rod cladding and thus ensure its sealing performance; when sealing the breach, a force along the radial direction of the simulated fuel rod is applied to the pressure rods (4-2) of the two sealing devices so that the two sealing devices can close the breach while maintaining the balance of force on the fuel rod; when opening the breach, the radial force is removed and the breach closing device (4) is moved to expose the breach.

8. The device for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel according to claim 1, characterized in that: The collecting device shell (5-1) of the collecting device (5) is integrated with the fuel rod cladding (3-2), serving as a place to contain aerosols released from the simulated fuel rod and facilitating sampling and measurement. Samples are drawn through a sampling tube (5-2) arranged on the collecting device shell (5-1).

9. The device for measuring the aerosol release fraction and rate at the rupture of lead-bismuth pile fuel according to claim 1, characterized in that: The particle size spectrometer (6) comprises a scanning mobility particle size spectrometer (6-1), a pre-measurement channel (6-2) directly connected to the scanning mobility particle size spectrometer (6-1), an inner cladding measurement channel (6-4), a collection device measurement channel (6-6), and a residual gas cleaning channel (6-9); the pre-measurement channel (6-2) is provided with a pre-measurement channel valve (6-3), the inner cladding measurement channel (6-4) is provided with an inner cladding measurement channel valve (6-5), the collection device measurement channel (6-6) is provided with a collection device measurement channel valve (6-7), and the residual gas cleaning channel (6-9) is provided with a residual gas cleaning channel valve (6-8).

10. A method for using the device for measuring the aerosol release fraction and rate at a lead-bismuth pile fuel breach according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: Conduct a transient experiment to explore the changing law of aerosol release ratio: Before starting use, assemble the entire device and check to ensure that all components are working properly, all connections are well sealed, there is no obvious damage or leakage, and the gas supply meets the experimental requirements; After the entire device is assembled, the rupture (3-5) of the simulated fuel rod is sealed by applying a tightening force to the rupture sealing device (4), the corresponding valve of the aerosol injection section is opened, and gas is injected into the simulated fuel rod (3). The fuel rod pressure gauge (3-8) is observed to stop the gas injection after reaching the specified working condition pressure. The fuel rod pressure gauge (3-8) is left to stand for a sufficient time and the reading is continuously observed. If the reading decreases significantly, the sealed simulated fuel rod (3) needs to be reassembled. If the reading is stable at the set working condition, it indicates that the simulated fuel rod (3) is airtight and meets the requirements of subsequent experiments. A preset amount of aerosol powder (2-7) is placed in the aerosol mixing device (2) and the motor (2-5) is turned on. After the rotating screw (2-1) transports the powder stably, the high-pressure gas tank (1) and the gas tank pressure regulating valve (7) are opened to inject gas into the aerosol mixing device (2) at a specified pressure. At this time, the stabilizing bypass pressure regulating valve (8) is opened to discharge the aerosol outward through the aerosol stabilizing bypass. After a preset time, the pre-measurement channel valve (6-3) is opened to absorb the aerosol in the aerosol stabilizing bypass through the pre-measurement channel (6-2) to measure the aerosol concentration at different times. After the aerosol concentration is stabilized, the stabilizing bypass pressure regulating valve (8) is closed, the aerosol mixing device (2) is connected to the simulated fuel rod (3), and the aerosol is injected into the simulated fuel rod (3) to a specified pressure. After the aerosol injection is completed, the entire device is left to stand to ensure that the aerosol in the simulated fuel rod (3) can be fully deposited. After the gas in the simulated fuel rod (3) is sampled through the sampling port (3-7), the particle size spectrometer (6) is turned on to absorb the sample through the measurement channel (6-4) in the cladding for measurement; The breach (3-5) is opened by the breach sealing device (4), and the gas begins to be released. When the fuel rod pressure gauge (3-8) shows a stable atmospheric pressure, the gas release is completed, and the particle size spectrometer (6) is turned on to absorb the sample gas in the collection device (5) through the collection device measurement channel (6-6) for measurement; Clean the aerosol in the collection device (5), purge and clean the entire device, record and organize the experimental data, and obtain the change law of the aerosol release ratio; according to the different working conditions set, change the working conditions and conduct the experiment according to the same method; Conduct a steady-state experiment to explore the changing law of gas release rate: Before starting use, assemble the entire device and check to ensure that all components are working properly, all connections are well sealed, there is no obvious damage or leakage, and the gas supply meets the experimental requirements; After the entire device is assembled, the breach (3-5) of the simulated fuel rod is sealed by applying a tightening force to the breach sealing device (4), the corresponding valve of the aerosol injection section is opened, gas is injected into the simulated fuel rod (3), and the fuel rod pressure gauge (3-8) is observed to terminate the gas injection after reaching the specified working condition pressure. The device is left to stand for a preset time and the reading of the fuel rod pressure gauge (3-8) is continuously observed. If the reading decreases significantly, the sealed simulated fuel rod (3) needs to be reassembled. If the reading stabilizes at the set working condition, it indicates that the simulated fuel rod (3) is airtight and meets the requirements of subsequent experiments. Starting the gas bypass of the aerosol injection section, injecting gas into the simulated fuel rod (3) until the fuel rod pressure gauge (3-8) shows a specified working pressure, and closing the aerosol injection section; The outlet pressure of the gas tank pressure regulating valve (7) is adjusted according to the preset pressure, the aerosol injection section is opened again and the breach sealing device (4) is operated at the same time to open the breach; the injection pressure of the gas tank pressure regulating valve (7) is adjusted based on the fuel rod pressure gauge (3-8) reading being stable at the set working condition value, ensuring that the fuel rod pressure gauge (3-8) reading remains unchanged, and the flow meter reading of the aerosol injection section is the flow rate of the breach (3-5); after the specified injection time, the aerosol injection section is closed and the experiment ends; Clean and organize the entire device, record and organize the experimental data, and obtain the law of change of gas release rate; according to the different working conditions set, change the working conditions, and use the same method to explore the effects of different internal pressures and rupture sizes on the gas release rate.

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