An experimental device and experimental method for preparing a deposition wall for nuclear accident aerosol simulation

Abstract

The application aims to provide an experimental device and experimental method for nuclear accident aerosol simulation deposition wall preparation, comprising an air compressor, an air storage tank, a drying tank, a flow meter, an aerosol generator, a transition section, a deposition experiment section, a control experiment section and a post-processing water tank; the air compressor, the air storage tank, the drying tank, the flow meter, the aerosol generator and the transition section are sequentially connected; the transition section is respectively connected with the post-processing water tank, the deposition experiment section and the control experiment section; and the outlets of the deposition experiment section and the control experiment section are respectively connected with the post-processing water tank. The deposition quality distribution of the prepared deposition wall can be measured and characterized, the uniformity of the distributed aerosol is considered in the loop design, and the deposition wall with relatively uniform particle mass distribution can be prepared.

Description

Technical Field

[0001] This invention relates to an experimental apparatus and method for preparing aerosol particle deposition walls. Background Technology

[0002] Following a severe accident such as a core meltdown in a reactor, the fuel element cladding of the core will fail over a large area, allowing radioactive nuclides to enter the primary coolant loop and eventually be released into the containment vessel along with the coolant. Aerosols are one of the main states in which radioactive nuclides exist in the gaseous space of the containment vessel, dispersing and migrating within it. Aerosol migration can occur through various pathways, with wall deposition being a significant one. The containment vessel's inner walls have extensive deposition surfaces, and the containment vessel contains numerous pieces of equipment and partitions. Under the influence of gravity, Brownian diffusion, thermophoresis, and diffusion, aerosols will move and deposit on equipment surfaces, compartment floors, and containment walls. Therefore, solid walls are one of the primary accumulation sites for radioactive aerosols within the containment vessel after a severe accident. The accompanying thermo-hydraulic phenomena associated with aerosol particle deposition on the walls can lead to secondary radioactive migration. Flash evaporation caused by a primary coolant leak will cause a large amount of vapor to disperse within the containment vessel, which will condense upon encountering the containment vessel's inner walls. The presence of aerosol particles on the wall surface affects the structure of the condensation surface, altering the distribution of condensation nuclei and potentially introducing thermal resistance during condensation, thus impacting condensation heat transfer characteristics. Furthermore, the generation of condensate on the wall surface can scour deposited aerosol particles, leading to further migration of radioactive aerosols and affecting the radioactive distribution characteristics within the containment. In summary, the processes of condensation heat transfer and aerosol scouring and migration on the aerosol particle deposition surface influence the thermohydraulic and radioactive migration characteristics within the containment. Therefore, to assess the potential mechanisms of these influences, it is necessary to conduct research on the condensation heat transfer and aerosol scouring behaviors of the aerosol particle deposition surface.

[0003] The release, migration, and deposition of aerosols continue for extended periods during actual accidents, and the deposition mechanisms are highly variable, including particle agglomeration, hygroscopic growth in humid environments, near-wall diffusion deposition, and natural settling in large spaces. This results in significant differences in aerosol deposition characteristics at different times and on different walls within the containment. Different particle sizes and densities of aerosol deposition on walls can have varying impacts on processes such as condensation heat transfer and aerosol scouring and migration. To accurately assess the influence of deposition on walls, experimental studies on deposition walls under single-variable conditions are essential. This places high demands on the preparation and measurement of aerosol particle-deposited walls.

[0004] For experimental studies related to aerosol scouring, the preparation of deposition walls is essential. Patent No. 202210175277.2 proposes a method for simulating aerosol scouring on walls, which includes the preparation of aerosol deposition walls; however, it does not mention the specific preparation method or the method for measuring the deposition volume. The experimental study "Experimental and Analytical Investigations of Aerosol Processes—Wash-Out and Wash-Down (Freitag, 2018)" used a method of sampling deposition samples to measure the deposition mass of different deposition walls. The measurement method is direct and reliable, and the experiment used large-space deposition, resulting in relatively uniform deposition density. However, the placement of numerous measurement samples alters the wall structure, which can significantly affect the scouring process.

[0005] Research revealed that gas phase space sampling and measurement is the primary method for assessing aerosol deposition characteristics. For example, the deposition characteristic measurement methods proposed in patents 201911116369.8 and 202210280460.9 sample the pipe space and measure deposition characteristics and rates under different conditions. However, these deposition characteristic measurements are only applicable to specific pipe environments and are difficult to accurately assess in large-space deposition environments. Patent 201210163291.7 proposes a visualized aerosol motion deposition observation system within a narrow rectangular channel, which can establish a narrow rectangular aerosol deposition environment and provide a simple assessment of aerosol deposition movement patterns; however, it is difficult to accurately assess the amount of aerosol deposited. Summary of the Invention

[0006] The purpose of this invention is to provide an experimental apparatus and method for preparing a nuclear accident aerosol simulated deposition wall, which can prepare a relatively uniformly distributed deposition wall and measure the deposition density distribution of aerosol particles, thereby supporting experiments on the thermal properties of the deposition wall.

[0007] The objective of this invention is achieved as follows:

[0008] This invention discloses an experimental apparatus for preparing a simulated nuclear accident aerosol deposition wall, characterized by comprising an air compressor, a gas storage tank, a drying tank, a flow meter, an aerosol generator, a transition section, a deposition experimental section, a control experimental section, and a post-treatment water tank. The air compressor, gas storage tank, drying tank, flow meter, aerosol generator, and transition section are connected sequentially. A first valve is installed between the gas storage tank and the drying tank, and a second valve is installed between the drying tank and the flow meter. The transition section is connected to the post-treatment water tank, the deposition experimental section, and the control experimental section respectively. A third valve is installed between the transition section and the control experimental section. A fourth valve is installed between the transition section and the post-treatment water tank. A fifth valve is installed between the transition section and the deposition experimental section. The outlets of the deposition experimental section and the control experimental section are connected to the post-treatment water tank respectively. A sixth valve is installed between the deposition experimental section and the post-treatment water tank, a seventh valve is installed between the control experimental section and the post-treatment water tank, and an eighth valve is installed in the post-treatment water tank.

[0009] The experimental apparatus for preparing a simulated deposition wall for nuclear accident aerosols according to the present invention may further include:

[0010] 1. The transition section includes an inlet section and a section body. The inlet section is installed at the front end of the section body, and an exhaust port is provided at the rear end of the section body. A transition flow equalization plate is provided between the inlet section and the section body, and a sampling tube is provided inside the section body.

[0011] 2. The deposition experimental section includes a deposition chamber and an experimental wall. The experimental wall is installed below the deposition chamber and the two are connected by a G-type clamp and a rubber gasket. Tempered glass is installed at the top of the deposition chamber. The front and rear sides of the deposition chamber are respectively provided with a chamber inlet section and an exhaust port. A deposition flow equalization plate is provided between the chamber inlet section and the deposition chamber. A sampling tube is provided in the deposition chamber and is connected to a particle size analyzer.

[0012] 3. The control experimental section has the same structure as the sedimentation experimental section, and a sampling plate is set at the bottom of the control experimental section.

[0013] An experimental method for preparing aerosol simulation deposition walls in nuclear accidents, characterized by:

[0014] Experimental preparation stage: The sample was evenly arranged on the experimental wall of the sealed deposition experimental section and the control experimental section and sealed. The aerosol used was dried at 120°C for 12 hours to remove moisture. The air compressor was started to charge the air tank for 20 minutes to prepare the high-pressure air source. The eighth valve was opened to inject water into the post-treatment water tank to the preset water level. The second to seventh valves were opened. The first valve was opened to introduce dry air and remove moisture. After the exhaust was completed, the first valve was closed. Dry aerosol was loaded into the aerosol generator. The second to seventh valves were closed. The pressure sensor of the transition section and the pressure sensor and flow meter of the deposition experimental section were connected. The particle size analyzer was turned on for preheating.

[0015] Experimental Phase: Open the first valve and adjust to the preset upstream pressure. Open the second and fourth valves to connect the transition section and the aerosol generator. Under the pressure of the upstream pipeline, the aerosol and delivery airflow flow into the transition section and enter the post-treatment water tank through the fourth valve. After the aerosol-containing airflow passes through the water tank, the aerosol is filtered. Adjust the second valve and monitor the flow meter and the pressure sensor of the transition section to establish the preset flow pressure. Open the sixth and seventh valves and adjust the third and fifth valves to introduce the delivery airflow into the deposition experimental section. Adjust the pipeline valves to stabilize the pressure of the transition section and detect the pressure sensor of the experimental chamber to establish a stable deposition chamber pressure environment. At the same time, establish the same pressure environment in the symmetrical test chamber. After the pipeline pressure environment is established, detect the pressure and flow parameters and adjust the valves to ensure the stability of the delivery and deposition environment. After stabilization, open the sampling pipeline valve of the deposition chamber every five minutes to sample and measure the gas at different locations. Record the sampling time and sampling location. Monitor the deposition situation inside the chamber in real time through the deposition chamber window.

[0016] End of Experiment: The experiment can be ended when the deposition time and estimated deposition amount meet the requirements. To end the experiment, first close the first valve, turn off the air compressor, cut off the gas source, turn off the particle size analyzer and copy the experimental data, turn off the power of each instrument, let the experimental device stand still, and wait for all aerosols in the device to settle. Then, open the deposition chamber to obtain the deposition wall surface, open the symmetrical test chamber to take out the sample after aerosol deposition, weigh and measure it to evaluate the aerosol deposition density and deposition amount distribution. Open the eighth valve to drain the water, and use clean water to clean the reverse treatment tank and experimental section. Use high-pressure airflow to purge the residual aerosols in the pipeline.

[0017] The advantages of this invention are:

[0018] 1. It can prepare particle deposition walls in a natural settling environment. Based on the experimental setup, aerosols are delivered and an aerosol dispersion environment is established. By utilizing the gravity settling effect of aerosols, they are allowed to settle naturally in the dispersion space, thereby preparing a particle deposition wall at the bottom of the space.

[0019] 2. It enables non-destructive and precise measurement of particle parameters on the deposition wall. The innovative design of the control measurement chamber solves the technical challenge of sample damage to the deposition wall. By weighing and measuring the sample in the sampling test section, the deposition mass of aerosol particles on the wall and the wall mass density distribution can be characterized. Simultaneously, the particle size distribution of settled aerosol particles can be obtained through the spatial aerosol sampling and measurement system in the test section chamber.

[0020] 3. The experiment can establish a uniform and stable aerosol dispersion environment. The experimental aerosol delivery pipeline is designed with a transition section to remove larger agglomerated particles. The delivery transition section and the experimental section together contain two stages of flow equalization resistance components, which, together with a large-sized deposition chamber, achieve the establishment of an aerosol environment with uniform particle size and uniform concentration. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the transition section;

[0023] Figure 3 This is a schematic diagram of the sedimentation experimental section;

[0024] Figure 4 This is a partial view of the sealing of the deposition wall.

[0025] Figure 5 This is a layout diagram for the sample. Detailed Implementation

[0026] The invention will now be described in more detail with reference to the accompanying drawings:

[0027] Combination Figure 1-5 This invention discloses an experimental apparatus for preparing aerosol particle deposition walls, comprising gas supply pipelines 1-6, aerosol delivery pipelines 7-11, an aerosol deposition wall preparation chamber 12, a deposition control measurement chamber 13, a post-treatment water tank 18, and connecting pipes. Pressure measuring points 8.3 and 12.4 are arranged at different locations to monitor pressure changes in the apparatus loop. The basic principle of the experimental apparatus is as follows: an air compressor provides the gas source for aerosol delivery. Aerosol particles are fluidized in the aerosol generator and delivered to the deposition experimental section along with the gas. The deposition experimental section is divided into two symmetrical chambers. One chamber serves as the preparation chamber, with the bottom forming the preparation wall. Aerosols settle in the chamber to prepare the deposition wall. The other chamber serves as the control chamber, providing an identical aerosol environment. Sample pieces are placed on the bottom wall to measure and characterize the deposition density of the prepared wall. Meanwhile, in order to improve the uniformity of aerosol delivery, a transition chamber is set in the aerosol delivery pipeline. The chamber is equipped with a flow equalization plate and a transition section. The delivery aerosol is drawn out from the transition chamber by pipeline sampling to ensure the uniformity of aerosol supply to the deposition chamber.

[0028] The deposition experimental section consists of a cavity 12, a pressure sensor 12.4, and a deposition wall 16. The cavity is equipped with a tempered glass viewing window 12.1, a flow equalization plate 12.2, and sampling tubes 12.3. The cavity is made of stainless steel. Rubber gaskets 12.5 and G-clamps 12.6 are used at the connection between the cavity and the deposition plate, and the deposition plate and the outer edge of the cavity are sealed by gaskets. A tempered glass 12.1a is embedded in the top of the stainless steel cavity for observing the aerosol environment within the cavity. Several sampling tubes 12.3 are equidistantly distributed within the cavity for sampling environmental aerosols. The flow equalization plate 12.2 is installed and fixed at the cavity inlet to evenly distribute the airflow. A flow regulating valve 11 and a pressure sensor 12.4 are fixedly installed at the inlet and cavity of the experimental section respectively using threaded clamps to regulate and detect the pressure and flow rate of the deposition experimental section. The control experimental section 13 adopts the same design as the deposition experimental section 12, with identical dimensions and apparatus. The difference lies in the fact that, in the control experimental section 13, a sampling sample 13.1 is set on the bottom plate surface, using the same material and surface finish as the plate wall. The deposition experimental section and the sampling experimental section are the core parts of the entire experimental setup. They primarily establish a stable and uniform aerosol dispersion space to create a natural aerosol settling environment, and through continuous natural settling, prepare the aerosol particle deposition wall. Simultaneously, aerosol sampling based on the sampling tube characterizes the aerosol particle size distribution level, while aerosol sampling of the wall deposition in the sampling experimental section characterizes the aerosol deposition quality and mass distribution, thereby quantifying the deposition level of the particle deposition wall.

[0029] The gas supply pipeline consists of an air compressor 1, an air storage tank 2, a drying tank 4, a flow meter 6, valves 3 and 5, and connecting pipes. Initially, air at a certain pressure can be stored in the air compressor 1 and air storage tank 2. The pressure reducing valve 3 is connected to the air storage tank 2, allowing adjustment of the delivery pressure during air distribution. The drying tank 4, placed in the delivery pipeline, can remove moisture and dry the delivered air. The gas delivery flow rate is adjusted and monitored using the regulating valve 5 and the flow meter 6, thereby ensuring the concentration of the delivered aerosol.

[0030] The aerosol delivery pipeline consists of an aerosol generator 7, a transition section 8, and valves 9, 10, and 11 connected to corresponding pipes. Aerosol particles are fluidized into the delivery gas within the aerosol generator 7. The transition section 8, located after the aerosol generator 7, contains a flow equalization plate 8.1, a sampling tube 8.2, and a pressure sensor 8.3, which improves the uniformity of aerosol concentration in the delivery gas. Following the transition section 8 are the inlet valve 11 for the deposition experiment section, the inlet valve 9 for the control experiment section, and the exhaust valve 10 for the transition section, used to regulate the aerosol delivery rate.

[0031] The post-treatment water tank consists of a water tank 18 and a valve 19. The water tank 18 is located downstream of the sedimentation test section 13, the control measurement test section 13 and the transition section 8. It can filter and discharge experimental exhaust gas. The bottom of the water tank 18 is equipped with a valve 19 for water filling and drainage.

[0032] like Figure 1 As shown, the device consists of gas supply pipelines 1-6, aerosol delivery pipelines 7-11, 18, a deposition chamber 12, a symmetrical measurement chamber 13, sampling and measurement pipelines 17, 20, and connecting pipes. Pressure reducing valves 3, regulating valves 5, 9, 10, 11, 14, 15, 20, and flow meters 6 are installed at relevant parts of the pipelines. A particle size analyzer 17 is also installed in the pipelines to measure the concentration and particle size of the aerosol. The core part of the pipeline is the aerosol delivery system, including an aerosol generator 7 and a transition section 8. After the transition section, it is connected to each experimental section sequentially via a deposition preparation chamber inlet valve 11, a deposition measurement chamber inlet valve 9, and an exhaust valve 10. To ensure uniform aerosol particle size within the deposition experimental section, the inlet pipeline is connected using a sampling method within the transition section. Regulating valves 5 and air flow meters 6 are located at the front end of the aerosol generator 7 to regulate and monitor the flow rate of the aerosol delivery gas. The pipeline uses pneumatic flexible hoses for easy disassembly of the aerosol generator 7 and replacement of the aerosol. The aerosol delivery section is connected to the drying tank 4 via pipeline to ensure the dryness of the air source and improve the quality of aerosol delivery. The deposition chamber 12 is the core of the experimental setup, connected to the aerosol delivery transition section 8 and the post-treatment water tank 18 via inlet and outlet flow regulating valves 1114. Inside the chamber, it is connected to the particle size analyzer 17 via a sampling regulating valve 20 and corresponding connecting pipelines. The symmetrical measurement chamber 13 adopts the same design and is arranged in parallel with the deposition chamber 12. The piping systems of all parts of the experiment are thus connected into a unified whole.

[0033] The overall working process of the experimental apparatus for preparing aerosol particle deposition walls is as follows: 1. Experimental preparation stage: Clean the aerosol deposition wall, install and seal the deposition chamber 12, and clean the bottom wall of the symmetrical measurement chamber 13. Evenly arrange the sample pieces 13.1 and seal the chamber. Dry the aerosols used at 120°C for 12 hours to remove moisture. Check that all pipeline valves are closed, start the air compressor 1 to charge the air tank 2 for 20 minutes to prepare a high-pressure air source. Open the injection / drainage valve 19 to inject sufficient water into the post-treatment water tank 18 to the preset water level. Connect the apparatus to the clean aerosol generator 7 without aerosols, open the regulating valves 5, 9, 10, 11, 14, and 15 in the circuit to connect each pipeline and experimental section, and open the pressure reducing valve 3 to introduce dry air into the apparatus and remove moisture from the space inside the apparatus. After venting, close pressure reducing valve 3, load dry aerosol into the aerosol generator, and connect it to the pipeline. Close all pipeline valves, connect the power supply to pressure sensors 8.3 and 12.4 and flow meter 6, and turn on particle size analyzer 17 for preheating. 2. Experimental stage: Open pressure reducing valve 3 to adjust to the preset upstream pressure, open regulating valve 5 and venting valve 10, connect transition section 8 and aerosol generator 7. Under the action of upstream pipeline pressure, aerosol and delivery airflow flow into transition section 8 and enter post-treatment water tank 18 through venting valve 10. The aerosol-containing airflow can be filtered after passing through the water tank. Adjust delivery valve 5 and monitor flow meter 6 and transition section pressure sensor 8.3 to establish a certain flow pressure. Open venting valves 14 and 15 of sedimentation experimental chamber and symmetrical measurement chamber, adjust chamber inlet valves 9 and 11, and introduce delivery airflow into sedimentation experimental section. 1. Establish a stable pressure environment in the deposition chamber 12 by adjusting the pressure of the transition section of the pipeline valves and detecting the pressure sensor 12.4 in the experimental chamber. Simultaneously, establish the same pressure environment in the symmetrical test chamber 13. After the pressure environment of the device pipeline is established, detect the pressure and flow parameters, and adjust the valves to ensure the stability of the delivery and deposition environment. After stabilization, open the sampling pipeline valve of the deposition chamber every five minutes to sample and measure the gas at different locations, record the sampling time and sampling location, and monitor the deposition situation inside the chamber in real time through the deposition chamber window 12.1. 3. End of experiment: The experiment can be ended when the deposition time and estimated deposition amount meet the requirements. When ending the experiment, first close the pressure reducing valve 3, turn off the air compressor 1, and cut off the gas source. Turn off the particle size analyzer 17 and copy the experimental data, and turn off the power to all instruments. Let the experimental device stand still and wait for all aerosols in the device to settle. Then, open the deposition chamber 12 to obtain the deposition wall. Open the symmetrical test chamber 13 and take out the sample 13.1 after the deposition of aerosols. Weigh and measure the aerosol deposition density and deposition distribution. Open the water tank drain / inject valve 19 to drain the water, and use clean water to clean the water tank 18 and the test section. Use high-pressure airflow to purge the residual aerosol in the pipeline.

[0034] like Figure 1 As shown, the aerosol delivery pipeline consists of an aerosol generator 7, a transition section 8, and an exhaust valve 10. The stainless steel aerosol generator 7, exhaust valve 10, and regulating valves 9 and 11 are connected to the inlet, outlet, and sampling port of the transition section 8 via stainless steel pipes and threaded fittings, respectively. To eliminate the influence of static electricity, the pipeline is grounded. Figure 2 As shown, the transition section device consists of several parts, including the main body, a flow equalization plate 8.1, sampling tubes 8.2, and a pressure sensor 8.3. The inlet section 8.5 and the outlet exhaust point of the section body 8.4 are respectively configured as expanding and contracting sections. The inlet section 8.5 is connected to the section body 8.4 via a flange, and the flow equalization plate 8.1 is clamped and fixed in the middle of the flange to evenly distribute the airflow at the inlet. Two sampling tubes 8.2 extend symmetrically into the middle of the transition section at the rear half of the section body, sampling aerosol distribution airflow, which is then distributed to the aerosol deposition chamber 12 and the symmetrical measurement chamber 13, respectively. The pressure sensor 12.4 is threadedly connected to the side wall opening of the transition section to measure the pressure value within the deposition transition section. The exhaust port is threadedly connected to the exhaust valve 10 for pressure reduction and exhaust.

[0035] like Figure 1 As shown, the deposition test section consists of a deposition test chamber 12, a symmetrical testing chamber 13, a deposition wall 16, exhaust valves 14 and 15, and connecting pipes. The deposition test chamber 12 and the symmetrical testing chamber 13 are connected to the transition section sampling pipe 8.2 via regulating valves 9 and 10 and corresponding pipes via threaded compression fittings. The outlet pipe of the test section extends 18 below the liquid surface of the post-treatment water tank to filter residual aerosols in the gas phase. Figure 3 As shown, the deposition chamber 12 is a cubic box used to establish an aerosol sedimentation environment. A glass window 12.1 is installed on the top of the chamber. The window consists of tempered glass 12.1a and a steel flange 12.1b. The glass is embedded in the flange and sealed with glass glue. The entire window is connected to the chamber by bolts and rubber gaskets, ensuring chamber sealing during the experiment and facilitating disassembly and cleaning after the experiment. The chamber inlet section 12.5 is designed as a gradually expanding section and is connected to the chamber via a flange. The flow equalization plate 12.2 is clamped and fixed at the inlet by the flange. Three sampling tubes 12.3 extend into the chamber and are equidistantly distributed at the bottom of the chamber near the experimental wall 16 for sampling environmental aerosols. Pressure sensors 12.4 are installed on the chamber wall to monitor pressure changes inside the deposition chamber 12. An outer edge is provided at the bottom of the chamber, such as... Figure 4 As shown, the cavity 12 is connected to the target deposition wall via its outer edge. The connection method is a G-type clamp 12.7. A rubber gasket 12.6 is sandwiched between the cavity and the wall for sealing the cavity.

[0036] like Figure 5As shown, the sample 13.1 is arranged on the bottom wall of the symmetrical sedimentation measurement chamber 13. The symmetrical measurement chamber 13 has the same structure as the sedimentation experiment chamber 12 and can provide the same sedimentation environment. The sample 13.1 is a small rectangular thin slice made of the same material as the sedimentation wall and is uniformly distributed across the entire sedimentation wall. It can be weighed to measure the sedimentation density at each location.

[0037] The sampling and measurement system consists of a particle size spectrometer 17, sampling valves 20, and corresponding connecting pipelines. To eliminate the electrostatic influence during the sampling process, the sampling pipelines are made of stainless steel and grounded. The three sampling valves 20 are installed in parallel on the three sampling pipelines, and the other side of the pipelines is connected to the particle size spectrometer 17. The sampling valves 20 can be switched in real time during the experiment to sample and measure the aerosol concentration and particle size in the deposition experimental chamber 12 and the symmetrical measurement chamber 13.

Claims

1. An experimental device for the preparation of a deposition wall for the simulation of aerosols from nuclear accidents, characterized in that it comprises: The experimental device comprises an air compressor, an air storage tank, a drying tank, a flow meter, an aerosol generator, a transition section, a deposition experiment section, a control experiment section, and a post-processing water tank. The transition section comprises an inlet section and a section body, the inlet section is installed at the front end of the section body, the rear end of the section body is provided with an exhaust port, a transition flow equalizing plate is arranged between the inlet section and the section body, and a sampling pipe is arranged in the section body. The deposition experiment section comprises a deposition chamber and an experiment wall surface, the experiment wall surface is installed below the deposition chamber, the two are connected through a G-shaped clamp and a rubber gasket, tempered glass is installed at the top end of the deposition chamber, a cavity inlet section and an exhaust port are arranged on the front and rear sides of the deposition chamber respectively, a deposition flow equalizing plate is arranged between the cavity inlet section and the deposition chamber, a sampling pipe is arranged in the deposition chamber, and the sampling pipe is connected with a particle size spectrometer.

2. The experimental device for the simulation of the deposition of aerosols from a nuclear accident on a wall according to claim 1, characterized in that: The control experiment section has the same structure as the deposition experiment section, and the control experiment section is provided with a sampling sample piece.

3. An experimental method for preparing a deposition wall surface for nuclear accident aerosol simulation, using the experimental device of claim 1 or 2, characterized by: Experiments Preparation stage: seal the deposition experiment section and the experiment wall surface of the control experiment section, and seal the sample pieces arranged uniformly on the experiment wall surface, dry the aerosol used at 120 DEG for 12 hours to remove moisture, prepare a high-pressure gas source by starting the air compressor to charge the air storage tank for 20 minutes, open the eighth valve to inject water into the post-processing water tank to a preset water level, open the second to seventh valves, open the first valve to introduce dry air and remove moisture, close the first valve after exhausting, load dry aerosol into the aerosol generator, close the second to seventh valves, connect the pressure sensor of the transition section, the pressure sensor of the deposition experiment section and the flow meter, and open the particle size spectrometer for preheating. Experimental stage: open the first valve to adjust to the preset upstream pressure, open the second and fourth valves, and connect the transition section and aerosol generator. Under the action of the upstream pressure, the aerosol and the dispensing gas flow into the transition section and pass through the fourth valve into the post-processing water tank. After the gas flow containing aerosol passes through the water tank, the aerosol is filtered. Adjust the second valve and monitor the flow meter and transition section pressure sensor to establish the preset flow pressure. Open the sixth and seventh valves, adjust the third and fifth valves, and introduce the dispensing gas flow into the deposition experiment section. Adjust the pipeline valve to stabilize the pressure of the transition section and detect the pressure sensor of the experiment chamber to establish a stable deposition chamber pressure environment. At the same time, establish the same pressure environment for the symmetrical test chamber. After the pipeline pressure environment is established, detect the pressure and flow parameters, adjust the valve to ensure the stability of the dispensing and deposition environment, and after stabilization, open the deposition chamber sampling pipeline valve every five minutes to sample and measure the gas at different positions. Record the sampling time and sampling position, and real-time monitor the deposition in the chamber through the deposition chamber window. Experimental end: when the deposition time and estimated deposition amount meet the requirements, the experiment can be ended. At the end of the experiment, first close the first valve, turn off the air compressor, cut off the air source, close the particle size spectrometer and copy the experimental data, close the instrument power supply, and stand the experimental device. After the aerosol in the device is completely settled, open the deposition chamber to obtain the deposition wall, open the symmetrical test chamber to take out the sample after deposition of the aerosol, and measure the weight to evaluate the aerosol deposition density and deposition amount distribution. Open the eighth valve to drain and use clean water to clean the post-processing water tank and the experimental section. Use high-pressure gas flow to blow off the residual aerosol in the pipeline.

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