A high-temperature liquid lead-bismuth particle deposition test device and test method

Abstract

The application discloses a kind of high-temperature liquid lead bismuth in particle deposition experimental research device and experimental method, belong to lead-based reactor thermal hydraulic technical field.The device of the present application includes lead bismuth storage tank, main circuit, test section, sampling branch, filtration branch, heat exchange branch, pipeline;The test section includes the rod bundle structure with wire winding, rectangular channel with visual window, rectangular channel with temperature measuring point;The test section of the device of the present application is designed so that the transposition can well carry out the test of the influence of thermal phoresis, gravity, buoyancy and other factors on particle deposition in lead bismuth medium, can also simulate the deposition of particles in liquid lead bismuth on the pipe wall and the rod bundle structure of reactor core, to analyze the particle deposition behavior in lead bismuth, while providing basic experimental data for numerical calculation in this field.

Description

Technical Field

[0001] This invention relates to the field of lead-based reactor thermal-hydraulic technology, specifically to a test apparatus and method for experimental research on particle deposition in high-temperature liquid lead-bismuth. Background Technology

[0002] Lead-cooled fast reactors use liquid lead-bismuth as the coolant, offering advantages such as strong natural circulation capability, chemical stability, and inherent safety, making them crucial in the development of miniaturized nuclear reactors. During reactor operation, debris or foreign particles from the reactor core may enter the coolant. Simultaneously, liquid lead-bismuth, being highly corrosive, causes dissolution corrosion and intergranular corrosion of reactor structural materials. Its high density further exacerbates corrosion, generating impurity particles in the coolant loop. As these particles propagate throughout the loop with the lead-bismuth flow, they deposit on pipe walls and reactor components. Particle deposition can disrupt normal reactor operation and even lead to reactor accidents.

[0003] Currently, due to the opacity, high temperature, and high corrosiveness of liquid metals, conducting related thermal-hydraulic experiments on liquid metals is difficult and costly. Because of their opacity, there is a lack of direct observation methods for the particle deposition process in lead-bismuth media, making it difficult to obtain detailed information about the deposition process. Studies are typically conducted using numerical calculations, lacking experimental data. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an experimental apparatus and method for studying the particle deposition characteristics in liquid lead-bismuth. This apparatus can simulate the deposition of particles in liquid lead-bismuth on pipe walls and reactor core rod bundle structures, thereby analyzing the particle deposition behavior in lead-bismuth and providing basic experimental data for numerical calculations in this field.

[0005] This invention provides a test apparatus for particle deposition in high-temperature liquid lead-bismuth, comprising a lead-bismuth storage tank, a main circuit, a test section, sampling branch 1, sampling branch 2, a filtration branch, a heat exchange branch, and pipelines;

[0006] The main circuit pipeline is equipped with, from the main circuit inlet section to the main circuit outlet section, a main circuit regulating valve, a main circuit flow meter, a main circuit electromagnetic pump, a main circuit pressure sensor 1, a main circuit temperature sensor 1, a test section, a main circuit temperature sensor 2, a main circuit pressure sensor 2, and a filter shut-off valve.

[0007] The top end of the lead bismuth storage tank is provided with an opening and is inserted into a heating rod, and the opening is sealed after the heating rod is inserted; the surface of the lead bismuth storage tank is provided with a temperature sensor 3 and a pressure sensor 3; the top end of the lead bismuth storage tank is connected with a main circuit outlet section pipeline, and the bottom end is connected with a main circuit inlet section pipeline; the lead bismuth storage tank is connected with a particle adding branch, and the particle adding branch is provided with a particle adding branch stop valve and a particle adding device connected with an argon gas cylinder 1; the surface of the particle adding device is provided with a screw rod pusher;

[0008] The front and rear ends of the test section on the pipeline of the main circuit are respectively provided with a test section front end stop valve and a test section rear end stop valve; the test section front end stop valve is located between the test section and the sampling branch 1, and the test section rear end stop valve is located between the test section and the sampling branch 2; the front end of the sampling branch 1 and the rear end of the sampling branch 2 are connected with a pressurizing branch in parallel; the surface of the test section is provided with a heat exchanger, and the two ends of the heat exchanger are connected with a heat exchange branch pipeline;

[0009] The filtering branch is connected at both ends of a filtering stop valve, and two groups of stop valves and filters are installed on the filtering branch, one group including a filtering branch stop valve 1 and a filter 1, and the other group including a filtering branch stop valve 2 and a filter 2; each group of stop valves and filters is connected in series, and the two groups are connected in parallel, and the two groups of filters are used alternately during use.

[0010] Further, the test section is one of a rod bundle structure test section with wire winding, a rectangular channel test section with a visualization window, and a rectangular channel test section with temperature measuring points, and the test section is wrapped with insulation cotton outside; the rod bundle structure in the channel of the rod bundle structure test section with wire winding can be heated with constant heat flow, the rod bundle structure is connected with external equipment through a wire, and temperature measuring points are arranged equidistantly on the outer wall of the test section to monitor the temperature.

[0011] Further, the rectangular channel test section with a visualization window includes a test section main body and a tempered glass window embedded in the middle of the test section main body; a graphite gasket and a tempered glass cover plate are sequentially mounted on the surface of the tempered glass window; epoxy resin sealant, high-temperature resistant glue or high-temperature resistant glass are coated between the test section main body, the graphite gasket and the tempered glass cover plate; a high-speed camera is arranged vertically to the flow direction outside the tempered glass window; the rectangular channel test section with temperature measuring points is heated in a constant heat flow mode at one side wall, and temperature measuring points are arranged equidistantly on the heated side wall to monitor the temperature change of the wall surface.

[0012] Further, the front end of the main circuit temperature sensor 2 is provided with a vacuum pump branch, and the vacuum pump branch is controlled by a vacuum pump controlled by a vacuum pump branch stop valve; a water tank, an adjusting valve and a circulating pump are sequentially mounted on the pipeline of the heat exchange branch for controlling the circulation of cooling water and the size of heat exchange.

[0013] Further, the pipeline of the sampling branch 1 is sequentially provided with a sampling branch 1 flow meter, a sampling branch 1 regulating valve, a sampling branch 1 ball valve and a sampling branch 1 sample container; the pipeline of the sampling branch 2 is sequentially provided with a sampling branch 2 flow meter, a sampling branch 2 regulating valve, a sampling branch 2 ball valve and a sampling branch 2 sample container; the sampling branch 1 regulating valve and the sampling branch 2 regulating valve regulate the flow rates of the sampling branch 1 and the sampling branch 2 to be consistent with the main circuit, and the sampling branch 1 ball valve and the sampling branch 2 ball valve are used to control the start and end of sampling.

[0014] Further, the test section is horizontally arranged on the pipeline of the main circuit or vertically arranged on the pipeline of the ascending section of the main circuit; the pipelines of the main circuit, the sampling branch 1, the sampling branch 2, the filtering branch, the heat exchange branch, the particle adding branch, the pressurizing branch and the vacuum pump branch are all wrapped with heat preservation cotton, and the pipeline of the main circuit is wrapped with a heat tracing belt.

[0015] The application further provides a test method of the device for testing deposition of particles in high-temperature liquid lead-bismuth.

[0016] Step 1: heat the lead-bismuth through the heating rod in the lead-bismuth storage tank, preheat the pipeline by electrifying the heat tracing belt wrapped on the pipeline of the main circuit, open the vacuum pump to vacuumize the pipeline of the main circuit, and close the vacuum pump;

[0017] Step 2: monitor the temperature of the lead-bismuth storage tank, inject particles into the particle adding device after the lead-bismuth is completely melted, push and tighten the particles through the screw pusher of the particle adding device, open the argon cylinder 1 after tightening, inject high-purity argon into the particle adding device to increase the pressure, and press the particles into the bottom of the lead-bismuth storage tank through the particle adding branch by the pressure difference to preliminarily mix the particles with the lead-bismuth, and close the argon cylinder 1;

[0018] Step 3: check whether the temperatures at all positions in the test circuit meet the requirements, open the main circuit regulating valve and the particle adding branch stop valve after the requirements are met, open the argon cylinder 1, gradually increase the pressure in the pipeline, maintain the pressure at a safe pressure at which the lead-bismuth can be pressed into the circuit, close the argon cylinder 1, and close the particle adding branch stop valve;

[0019] Step 4: Turn on the main loop electromagnetic pump to make the lead bismuth circulate in the main loop; open the sampling branch 1 ball valve and the sampling branch 2 ball valve, adjust the sampling branch 1 regulating valve and the sampling branch 2 regulating valve, and calculate the flow rate of the sampling branch 1 and the sampling branch 2 through the sampling branch 1 flowmeter and the sampling branch 2 flowmeter to make the flow rate of the sampling branch 1 and the sampling branch 2 consistent with that of the main loop, close the sampling branch 1 ball valve and the sampling branch 2 ball valve, and replace the sampling branch 1 sample container and the sampling branch 2 sample container; open the sampling branch 1 ball valve and the sampling branch 2 ball valve at different times during the test, sample within the same time period, close the sampling branch 1 ball valve and the sampling branch 2 ball valve after sampling is completed, replace the new sampling branch 1 sample container and the sampling branch 2 sample container, and record the samples at different times for subsequent sample analysis;

[0020] Step 5: After the lead bismuth starts to circulate in the main loop, turn on the heat tracing band to heat the parts of the test section that need to be heated at the same heat flux density, continuously observe the temperature change of the test section measuring point from the start of the test, and when the measuring point temperature stabilizes at a certain temperature without changing, it indicates that the particle deposition at this point has reached equilibrium, and the time and other test data at this time are recorded; open the heat exchange branch regulating valve and the heat exchange branch circulating pump, change the heat exchange amount according to the requirements of each test condition setting, and evaluate the influence of thermophoresis on particle deposition;

[0021] Step 6: After the test is completed, close the filter cutoff valve to make the lead bismuth flow into the filter branch, alternately open the filter branch cutoff valve 1 and the filter branch cutoff valve 2 to make the lead bismuth flow through the filter 1 and the filter 2 for filtration; when the filter 1 reaches the maximum filtration carrying capacity, close the filter branch cutoff valve 1 and open the filter branch cutoff valve 2 to replace the filter 2, and the two groups are alternately replaced; after the lead bismuth no longer has particle impurities filtered out, open the filter cutoff valve;

[0022] Close the heat exchange branch regulating valve, the heat exchange branch circulating pump, and the main loop electromagnetic pump, close the test section front end cutoff valve and the test section rear end cutoff valve; open the pressurization branch cutoff valve 1 and the pressurization branch cutoff valve 2 of the pressurization branch and the argon cylinder 2, inject high-purity argon into the main loop pipeline, and appropriately open the pressure relief branch regulating valve to relieve the pressure of the lead bismuth storage tank, so that the pressure can press the lead bismuth back into the lead bismuth storage tank; close the argon cylinder 2, close the pressurization branch cutoff valve 1 and the pressurization branch cutoff valve 2 of the pressurization branch, and close the pressure relief branch regulating valve;

[0023] Close the pipeline heat tracing band and the heating rod, close the main loop regulating valve, and naturally cool the lead bismuth in the lead bismuth storage tank and the lead bismuth in the test section; cut out the test section and slice the test section for subsequent analysis.

[0024] Further, before the test starts, the pre-test section stop valve and the post-test section stop valve are opened to ensure that the pressure and temperature of all pipes and devices in the test loop are consistent with the external environment when the test is not in progress.

[0025] Further, the wire-wound rod bundle structure test section is used to simulate the deposition of particles on the fuel rods in the reactor core, and the time for the particles to reach the equilibrium state and the influence on heat exchange can be measured through the temperature change of the temperature measuring point, and the subsequent slicing can be used to study the particle distribution rule; the visual rectangular channel test section is mainly used to study the deposition behavior of particles at the wall surface, a high-speed camera is used to shoot the migration and deposition behavior of particles in the test section and subsequent analysis is performed; when the lead bismuth flows through the visual window during the test using the visual test section, the deposition and distribution development image of the particles in the wall surface in the lead bismuth medium can be collected by using the high-speed camera, data analysis and calculation are performed, and in combination with the vertical narrow rectangular channel particle deposition visualization test, the motion and deposition rule of particles in the high-temperature lead bismuth medium and the influencing factors of the particle migration and deposition rule in the lead bismuth fluid can be obtained; the rectangular channel test section with the temperature measuring point can be used to measure the time for the particle deposition on the wall surface of the rectangular channel to reach the equilibrium state and the influence on heat exchange.

[0026] Further, the influence of gravity on the deposition can be obtained by comparing and analyzing the particle deposition in the horizontal state or the vertical state of the test section.

[0027] The present application has the following beneficial effects:

[0028] 1. The device can simulate the phenomenon that the lead bismuth carries particles and deposits during the normal flow process in the channel.

[0029] 2. The particle adding device of the device can make the replacement process of different particles more convenient, and the filtering section can realize the switching of the particle types in the test loop without replacing new lead bismuth.

[0030] 3. The design of the test section of the device makes the test station capable of well performing the test on the influence of factors such as thermal migration, gravity and buoyancy on the particle deposition in the lead bismuth medium, and can realize the visualized research on the deposition formation process of the particles in the lead bismuth medium at the wall surface, the deposition characteristic research of the particles on the rod bundle surface and other multipurpose test researches. The information such as the thermal migration of the particles, the deposition thickness, the deposition distribution and the deposition form can be obtained, and the test data obtained are used to study the migration and deposition mechanism of the particles in the lead bismuth alloy fluid. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a schematic diagram of the particle deposition test loop of the horizontal test section of the device.

[0032] Figure 2The schematic diagram of the particle deposition test loop of the vertical test section of the device of the present application;

[0033] Figure 3 The schematic diagram of the test section with wire-wound rod bundle structure of the device of the present application;

[0034] Figure 4 The schematic diagram of the test section with visualization window of the device of the present application;

[0035] Figure 5 The schematic diagram of the test section with temperature measuring point of the device of the present application;

[0036] Figure 6 The schematic diagram of the overall arrangement of the design of the test section with visualization window of the device of the present application.

[0037] In the figure: 1, argon cylinder 1; 2, particle adding device; 3, screw rod pusher; 4, particle adding branch pipeline; 5, particle adding branch stop valve; 6, lead bismuth storage tank; 7, heating rod; 8, storage tank pressure sensor; 9, storage tank temperature sensor; 10, main loop inlet section pipeline; 11, main loop regulating valve; 12, main loop flow meter; 13, main loop electromagnetic pump; 14, main loop pressure sensor 1; 15, main loop temperature sensor 1; 16, sampling branch 1 flow meter; 17, sampling branch 1 regulating valve; 18, sampling branch 1 ball valve; 19, sampling branch 1 sample container; 20, test section front end stop valve; 21, pressurizing branch stop valve 1; 22, pressurizing branch stop valve 2; 23, argon cylinder 2; 24, test section; 25, heat exchange branch water tank; 26, heat exchange branch regulating valve; 27, heat exchange branch circulating pump; 28, heat exchanger; 29, test section rear end stop valve; 30, sampling branch 2 flow meter; 31, sampling branch 2 regulating valve; 32, sampling branch 2 ball valve; 33, sampling branch 2 sample container; 34, vacuum pump branch stop valve; 35, vacuum pump; 36, main loop temperature sensor 2; 37, main loop pressure sensor 2; 38, filtration stop valve; 39, filtration branch stop valve 1; 40, filter 1; 41, filtration branch stop valve 2; 42, filter 2; 43, main loop outlet section pipeline; 44, pressure relief branch regulating valve; 45, heating equipment; 46, test section temperature sensor; 47, wire-wound rod bundle structure; 48, visualization window; 49, high-speed camera; 50, test section main body of the rectangular channel with visualization window; 51, graphite gasket; 52, toughened glass partition. DETAILED DESCRIPTION

[0038] The present application is further described in the following detailed description with reference to the accompanying drawings.

[0039] Example 1

[0040] As Figure 1As shown, the application provides a high-temperature liquid lead-bismuth particle deposition test research device, which comprises a main loop, a test section, a particle adding branch, a lead-bismuth storage tank, a circulating electromagnetic pump, a sampling branch, a filtering branch, a heat exchange branch, and pipelines and instruments.

[0041] The main loop is provided with a main loop regulating valve, a main loop flow meter, a main loop electromagnetic pump, a main loop temperature sensor 1, a main loop pressure sensor 1, a test section, a main loop temperature sensor 2, a main loop pressure sensor 2, a filtering stop valve and other instruments and equipment; wherein the test section is transversely arranged on the pipeline of the main loop.

[0042] The outer sides of the main loop and each branch are wrapped with thermal insulation cotton to prevent the lead-bismuth from solidifying due to temperature reduction during flow;

[0043] The main loop regulating valve is arranged between the outlet of the lead-bismuth storage tank and the main loop flow meter, and is used for regulating the flow of the main loop.

[0044] The test section has three types, which are a rod bundle structure with wire winding, a rectangular channel with a visualization window, and a rectangular channel with a temperature measuring point, and the outer side of the test section is provided with a single-sided / full-surface heat exchanger, and the outer side of the test section is not completely wrapped with thermal insulation cotton.

[0045] The test section is provided with a test section front end stop valve and a test section rear end stop valve at the two ends of the main loop, which are used for being closed before the lead-bismuth backflow at the end of the test, so as to ensure that the lead-bismuth can be stored in the test section for subsequent slicing or test section replacement.

[0046] The side of the test section without thermal insulation cotton is connected with a heat exchanger to cool the side wall surface to enhance the thermophoresis effect, the existing branch of the heat exchanger is a heat exchange branch, and a heat exchange branch circulating pump, a heat exchange branch water tank and a heat exchange branch regulating valve are arranged to control the circulation of cooling water and the size of heat exchange;

[0047] The rod bundle structure test section with wire winding is as shown in Figure 3 The rod bundle structure in the channel can be heated to ensure constant heat flow, the rod bundle structure is connected with external equipment through wires, temperature measuring points are arranged at equal intervals on the outer wall of the test section and are connected with external equipment through wires along the same direction as the heating wires, so as to monitor the temperature of the temperature measuring points, and the arrangement of the wires and the temperature measuring points ensures the minimum influence on the internal flow field.

[0048] The rectangular channel test section with a visualization window is as shown in Figure 4 , 6As shown, the test section is divided into a test section main body, a graphite gasket, a tempered glass cover plate, and several bolts. The test section main body, the graphite gasket, and the tempered glass cover plate are coated with epoxy resin sealant. A high-speed camera is arranged opposite the tempered glass window of the test section in the flow direction to take pictures of the particle deposition distribution process during the test. In order to ensure that the upper and lower dimensions of the rectangular channel of the test section are consistent and sealed, the test section is not fixed by welding, but by supporting and pouring high-temperature resistant epoxy resin or high-temperature resistant glue, glass, and other sealing methods to achieve the purpose of sealing.

[0049] The rectangular channel test section with temperature measuring points, as shown in Figure 5 The side wall is heated by a constant heat flow, and temperature measuring points are arranged equidistantly on the side wall to monitor the temperature change of the wall.

[0050] The particle addition branch includes an argon gas cylinder 1, a particle addition device, and a pipeline. The argon gas cylinder 1 is connected to a section of stainless steel pipeline through a flexible gas pipe, and the interface between the two is air-tight. The stainless steel pipeline is connected to the top of the particle addition device, and a stainless steel pipeline is connected to the bottom of the particle addition device and extends into the bottom of the lead-bismuth storage tank. The particle addition device is open at the top and is equipped with a screw rod pusher. When particles need to be added, the required particles are added at the opening, and the screw pusher pushes the particles into the addition device while achieving the sealing effect. The particle concentration in the control loop is controlled by controlling the mass of the added particles.

[0051] The lead-bismuth storage tank is used to store lead-bismuth. The top of the lead-bismuth storage tank is open and a heating rod is inserted into it to melt the lead-bismuth. The opening is sealed after the heating rod is inserted. The lead-bismuth storage tank is equipped with a pressure sensor and a temperature sensor to monitor the state of the lead-bismuth in the storage tank. The upper end of the storage tank is connected to the outlet section of the main loop, and the lower end is connected to the inlet section of the main loop. A pipeline that is open to the external environment is provided above the storage tank, and an adjusting valve is provided to release the internal pressure of the storage tank.

[0052] The main loop electromagnetic pump is used to drive the lead-bismuth to circulate in the loop.

[0053] There are two sampling branches, one located at the front end of the test section and the other located at the rear end of the test section. Flowmeters, adjusting valves, ball valves, and sample containers are installed on the sampling branches. The adjusting valves and the ball valves are connected in series. The flow rate of the sampling branch calculated by the flowmeter is consistent with the flow rate of the lead-bismuth in the main loop. The adjusting valves are used to adjust the sampling flow rate, the ball valves are used to control the start or end of sampling, and the sample containers are used to receive the sampled lead-bismuth samples.

[0054] Two groups of same cut-off valves and filters are installed on the filter section, each group of cut-off valves and filters is connected in series, and the two groups are connected in parallel to filter the particle impurities in the liquid lead bismuth in a non-test state, and after the test is completed, the lead bismuth fluid is filtered to filter out the particles mixed in the lead bismuth fluid, so as to avoid affecting the next test, and the two groups of filters are used alternately in use, so that when one group of filters reaches the maximum carrying capacity, the other filter is opened, the filter is closed and a new filter is replaced, and the on-line replacement function is realized.

[0055] Embodiment 2

[0056] As Figure 2 shown, the application further provides a high-temperature liquid lead bismuth particle deposition test research device, and the test loop is basically the same as that in embodiment 1, and the only difference is that the test section is changed from a horizontal state to a vertical state and is placed on the ascending section of the main loop. The comparison of the results of the two test loops can be used to compare the influence of gravity on particle deposition.

[0057] Embodiment 3

[0058] Before the test, in addition to the opening of the test section front end cut-off valve, the test section rear end cut-off valve and the filter cut-off valve, the remaining valves are in the closed state.

[0059] 1. Preheating stage:

[0060] The pressure and temperature of all pipelines and devices in the loop are consistent with the external environment in a non-test state. In the test start stage, the lead bismuth is heated through the heating rod in the lead bismuth storage tank, and the pipeline is preheated by electrifying the heat tracing belt wound on the pipeline. The heating rod and the heat tracing belt are controlled by a self-control system for constant temperature control. The vacuum pump is opened to vacuumize the pipeline, and the vacuum pump is closed.

[0061] The temperature of the lead bismuth storage tank is monitored, and after the lead bismuth is completely melted, enough particles are injected into the particle adding device through the screw pusher and are tightened. After tightening, the argon cylinder 1 is opened, high-purity argon is injected into the particle adding device to increase the pressure, and the particles are pressed into the bottom of the lead bismuth storage tank through the pressure difference, and are preliminarily mixed with the lead bismuth. The argon cylinder 1 is closed.

[0062] 2. Lead bismuth upsurge stage:

[0063] Check whether the temperature at each position in the test loop meets the requirements, open the main loop regulating valve and the particle adding branch cut-off valve, open the argon cylinder 1, gradually increase the pressure in the pipeline, and maintain a safe pressure that can press the lead bismuth onto the loop, close the argon cylinder 1, and close the cut-off valve on the particle adding branch.

[0064] 3. Test phase:

[0065] Turn on the electromagnetic pump to make the lead bismuth circulate in the loop. At the same time, open the two sampling branch ball valves, adjust the two sampling branch regulating valves, convert the sampling branch flow rate through the sampling branch flow meter, make the sampling branch lead bismuth flow rate consistent with the main loop, close the ball valve, replace the sampling containers of each sampling branch. Open the ball valves of the two sampling branches at different times of the test, sample within the same time period, close the ball valves after sampling is complete, replace new sample containers and make records for subsequent sample analysis.

[0066] After the lead bismuth begins to circulate in the loop, turn on the heating equipment to heat the parts of the test section that need to be heated at the same heat flux density. Continuously observe the temperature changes of the test section measuring points from the start of the test. When the measuring point temperature stabilizes at a certain temperature and does not change, it indicates that the particle deposition at that point has reached equilibrium. Record the time and other test data at that time.

[0067] Turn on the heat exchange branch regulating valve and the heat exchange branch circulating pump. Change the heat exchange amount according to the requirements of each test condition setting to evaluate the influence of thermophoresis on particle deposition.

[0068] 4. Filtration phase:

[0069] After the test is completed, close the filtration stop valve, alternately open the stop valve 1 of the filtration branch and the stop valve 2 of the filtration branch to make the lead bismuth flow through filter 1 and filter 2 for filtration. When one of the filters reaches the maximum filtration carrying capacity, close the stop valve corresponding to that filter, while opening the stop valve corresponding to the other filter, and replace the filter that has reached the maximum filtration carrying capacity. After there are no more particle impurities filtered out of the lead bismuth, open the filtration stop valve.

[0070] 5. Backflow phase:

[0071] Close the heat branch regulating valve, the heat exchange branch circulating pump, and the main loop electromagnetic pump. Close the test section front end stop valve and the test section rear end stop valve. Open the two stop valves of the pressurization branch where the argon cylinder 2 is located, open the argon cylinder 2, inject high-purity argon into the upper pipeline of the main loop, and appropriately open the pressure relief branch regulating valve to relieve the pressure of the liquid storage tank, so that the pressure can press the lead bismuth back into the lead bismuth storage tank. Close the argon cylinder 2, close the two stop valves of the pressurization branch, and close the pressure relief branch regulating valve.

[0072] 6. Test completion:

[0073] Close the pipeline heat tracing and heating rods, close the main loop regulating valve, and allow the lead bismuth in the liquid storage tank and the lead bismuth in the test section to cool naturally. Cut out the test section and slice it for subsequent analysis.

[0074] 7. Data analysis:

[0075] As Figure 1 In the experiment, the sample obtained by sampling on the sampling branch 1 is defined as the upstream sample, and the sample obtained by sampling on the sampling branch 2 is defined as the downstream sample. After the experiment, the upstream and downstream lead-bismuth samples sampled at the same time period are analyzed, and the particle concentrations in the upstream and downstream samples are measured by conductivity measurement method, respectively. The particle concentration in the upstream sample is C up , and the particle concentration in the downstream sample is C down , so as to obtain the particle deposition efficiency η of the test section within a certain time period:

[0076]

[0077] In the formula: C up is the particle concentration in the upstream sample, g / m 3 ;

[0078] C down is the particle concentration in the downstream sample, g / m 3 ;

[0079] According to the test requirements, the particle deposition efficiency under different test conditions can be obtained.

[0080] At the same time, the particle deposition velocity can be obtained:

[0081]

[0082] The Figure 3 , 4 , 5 are different test sections, the Figure 3 is a test section with a wire-wound rod bundle structure for simulating the deposition of particles on the fuel rods in the reactor core. The temperature change of the temperature measuring point can be used to measure the time when the particle deposition reaches the equilibrium state and the influence on heat exchange. The subsequent slicing can be used to study the particle distribution rule. Figure 4 The test section is a visual rectangular channel, which is mainly used to study the deposition behavior of particles at the wall surface. A high-speed camera and an electronic scanning microscope are used to shoot the migration and deposition behavior of particles in the test section and to perform subsequent analysis. Figure 5 The test section is a rectangular channel with a temperature measuring point, which can be used to measure the time when the particle deposition on the wall surface of the rectangular channel reaches the equilibrium state and the influence on heat exchange.

[0083] In the visualization test stage, the heat exchanger branch equipment is opened, the electromagnetic pump is opened, the lead bismuth is circulated in the loop. The sampling branch ball valve is opened, the sampling branch regulating valve is adjusted, the sampling branch flow rate is converted through the sampling branch flowmeter so that the sampling branch lead bismuth flow rate is consistent with the main loop, the ball valve is closed, and the sampling container is replaced. In addition, when the lead bismuth flows through the visualization window, the deposition distribution development image of the particles in the lead bismuth medium at the wall surface can be collected by using a high-speed camera, data analysis and calculation are carried out, and the particle motion deposition law in the high-temperature lead bismuth medium and the influencing factors of the particle migration deposition law in the lead bismuth fluid can be obtained by combining the particle deposition visualization test of the vertical narrow rectangular channel.

[0084] The vertical state of the test section of example 2 is the same as the specific embodiment of example 3 in the preheating, upsurging, filtering, backflowing and ending stages, and the like, and will not be repeated here.

[0085] The above is only an embodiment of the present application, and is not a limitation on the protection scope of the present application. Any equivalent structural transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A device for experimental research on particle deposition in high-temperature liquid lead-bismuth, characterized in that, It includes a lead-bismuth storage tank (6), a main circuit, a test section, sampling branch 1, sampling branch 2, a filtration branch, a heat exchange branch, and pipelines; The main circuit pipeline is equipped with a main circuit regulating valve (11), a main circuit flow meter (12), a main circuit electromagnetic pump (13), a main circuit pressure sensor 1 (14), a main circuit temperature sensor 1 (15), a test section (24), a main circuit temperature sensor 2 (36), a main circuit pressure sensor 2 (37), and a filter shut-off valve (38) in sequence from the main circuit inlet section (10) to the main circuit outlet section (43). The lead-bismuth storage tank (6) has an opening at its top where a heating rod (7) is inserted. The opening is then sealed after the heating rod (7) is inserted. The surface of the lead-bismuth storage tank (6) is equipped with a temperature sensor (8) and a pressure sensor (9). The top of the lead-bismuth storage tank (6) is connected to the main circuit outlet section pipeline (43), and the bottom is connected to the main circuit inlet section pipeline (10). The lead-bismuth storage tank (6) is connected to a particle addition branch. The particle addition branch is equipped with a particle addition branch shut-off valve (5) and a particle addition device (2) connected to an argon cylinder 1 (1). The surface of the particle addition device (2) is equipped with a screw rod pusher (3). The front and rear ends of the test section (24) of the main circuit pipeline are respectively equipped with a front stop valve (20) and a rear stop valve (29); the front stop valve (20) is located between the test section (24) and the sampling branch 1, and the rear stop valve (29) is located between the test section (24) and the sampling branch 2; the front end of the sampling branch 1 and the rear end of the sampling branch 2 are connected in parallel with a pressurization branch; a heat exchanger (28) is provided on the surface of the test section (24), and the two ends of the heat exchanger (28) are connected to the heat exchange branch pipeline; The filter branch is connected to both ends of the filter stop valve (38). Two sets of stop valves and filters are installed on the filter branch. One set includes filter branch stop valve 1 (39) and filter 1 (40), and the other set includes filter branch stop valve 2 (41) and filter 2 (42). Each set of stop valves and filters is first connected in series, and then the two sets are connected in parallel. The two sets of filters are used alternately during use. The test section (24) is one of the following: a test section with a rod bundle structure with winding wire, a test section with a rectangular channel with a visualization window, or a test section with a rectangular channel with temperature measuring points. The test section is wrapped with thermal insulation cotton. The rod bundle structure inside the channel of the test section with winding wire can be heated by a constant heat flow. The rod bundle structure is connected to external equipment through wires. Temperature measuring points are set at equal intervals on the outer wall of the test section (24) to monitor the temperature.

2. The experimental apparatus for particle deposition in high-temperature liquid lead-bismuth according to claim 1, characterized in that, The rectangular channel test section with a visualization window includes a main body of the test section and a tempered glass window embedded in the middle of the main body of the test section; a graphite gasket and a tempered glass cover are sequentially installed on the surface of the tempered glass window; epoxy resin sealant, high-temperature resistant adhesive, or high-temperature resistant glass are applied between the main body of the test section and the graphite gasket and the tempered glass cover; a high-speed camera is arranged perpendicular to the flow direction on the outside of the tempered glass window; the rectangular channel test section with temperature measuring points adopts a constant heat flow heating method on one side wall, and temperature measuring points are arranged at equal intervals on the heated side wall to monitor the temperature change of the wall.

3. The experimental apparatus for particle deposition in high-temperature liquid lead-bismuth according to claim 2, characterized in that, The main circuit temperature sensor 2 (36) is equipped with a vacuum pump branch at its front end. The vacuum pump branch is a vacuum pump (35) controlled by the vacuum pump branch shut-off valve (34). The heat exchange branch water tank (25), heat exchange branch regulating valve (26) and heat exchange branch circulation pump (27) are installed in sequence on the pipeline of the heat exchange branch to control the cooling water circulation and the amount of heat exchange.

4. The experimental apparatus for particle deposition in high-temperature liquid lead-bismuth according to claim 3, characterized in that, The sampling branch 1 pipeline is sequentially equipped with a sampling branch 1 flow meter (16), a sampling branch 1 regulating valve (17), a sampling branch 1 ball valve (18), and a sampling branch 1 sample container (19); the sampling branch 2 pipeline is sequentially equipped with a sampling branch 2 flow meter (30), a sampling branch 2 regulating valve (31), a sampling branch 2 ball valve (32), and a sampling branch 2 sample container (33); the sampling branch 1 regulating valve (17) and the sampling branch 2 regulating valve (31) adjust the flow rate of sampling branch 1 and sampling branch 2 to be consistent with the main circuit (Ⅰ), and the sampling branch 1 ball valve (18) and the sampling branch 2 ball valve (32) are used to control the start and end of sampling.

5. The experimental apparatus for particle deposition in high-temperature liquid lead-bismuth according to claim 4, characterized in that, The test section (24) is placed horizontally on the main circuit pipe or vertically on the main circuit rising section pipe; the outside of the main circuit, sampling branch 1, sampling branch 2, filtration branch, heat exchange branch, particle addition branch, pressurization branch and vacuum pump branch pipes are all wrapped with heat insulation cotton, and the main circuit pipes are wrapped with heat tracing tape.

6. A test method for the experimental research apparatus for particle deposition in high-temperature liquid lead-bismuth as described in claim 5, characterized in that, Includes the following steps: Step 1: Heat the lead bismuth using the heating rod (7) in the lead bismuth storage tank (6), and simultaneously energize the heat tracing cable wrapped around the main circuit pipeline to preheat the pipeline; turn on the vacuum pump (35) to evacuate the main circuit pipeline, and then turn off the vacuum pump (35). Step 2: Monitor the temperature of the lead-bismuth storage tank (6). After the lead-bismuth has completely melted, inject the particles into the particle adding device (2). Push the particles in through the spiral pusher (3) of the particle adding device (2) and tighten it. After tightening, open the argon cylinder 1 (1) and inject high-purity argon into the particle adding device (2) to increase the pressure. Through the pressure difference, the particles are pushed into the bottom of the lead-bismuth storage tank (6) through the particle adding branch to be initially mixed with the lead-bismuth. Then close the argon cylinder 1 (1). Step 3: Check whether the temperature at each point in the test circuit meets the requirements. After the requirements are met, open the main circuit regulating valve (11) and the particle addition branch shut-off valve (5), open the argon cylinder 1 (1), gradually increase the pressure in the pipeline, maintain it at a safe pressure that can press lead and bismuth into the circuit, close the argon cylinder 1 (1), and close the particle addition branch shut-off valve (5). Step 4: Turn on the main circuit electromagnetic pump (13) to make the lead and bismuth circulate in the main circuit; open the ball valve (18) of sampling branch 1 and the ball valve (32) of sampling branch 2, adjust the regulating valve (17) of sampling branch 1 and the regulating valve (31) of sampling branch 2, and calculate the flow rate of sampling branch 1 and sampling branch 2 through the flow meter (16) of sampling branch 1 and the flow meter (30) of sampling branch 2 so that the lead and bismuth flow rate of sampling branch 1 and sampling branch 2 is consistent with the main circuit, and close the ball valve (18) of sampling branch 1 and the ball valve (32) of sampling branch 2. Replace the sample container (19) of sampling branch 1 and the sample container (33) of sampling branch 2 with the ball valve (32) of branch 2 at different times during the experiment. Take samples within the same time period. After the sampling is completed, close the ball valve (18) of sampling branch 1 and the ball valve (32) of sampling branch 2, replace the sample container (19) of sampling branch 1 and the sample container (33) of sampling branch 2, and record the samples at different times for subsequent sample analysis. Step 5: After lead and bismuth begin circulating in the main circuit, turn on the heat tracing cable to heat the parts of the test section (24) that need to be heated with equal heat flux density. Continuously observe the temperature change of the measuring points in the test section from the start of the test. When the temperature of the measuring point stabilizes at a certain temperature and does not change, it indicates that the particle deposition at that point has reached equilibrium. Record the time and other test data at that time. Turn on the heat exchange branch regulating valve (26) and the heat exchange branch circulation pump (27). According to the requirements of each test condition, change the amount of heat exchange to evaluate the effect of thermophoresis on particle deposition. Step 6: After the test is completed, close the filter shut-off valve (38) to allow lead and bismuth to flow into the filter branch. Alternately open the shut-off valve 1 (39) and the shut-off valve 2 (41) of the filter branch to allow lead and bismuth to flow through filter 1 (40) and filter 2 (42) for filtration. When filter 1 (40) reaches its maximum filtration capacity, close the filter branch shut-off valve 1 (39) and open the filter branch shut-off valve 2 (41) to replace it with filter 2 (42). Alternate between the two sets. After no more particulate impurities are filtered out from the lead and bismuth, open the filter shut-off valve (38). Close the heat exchange branch regulating valve (26), heat exchange branch circulation pump (27) and main circuit electromagnetic pump (13), and close the front end shut-off valve (20) and rear end shut-off valve (29) of the test section; open the pressurization branch shut-off valve 1 (21), pressurization branch shut-off valve 2 (22) and argon cylinder 2 (2) of the pressurization branch, inject high-purity argon into the main circuit pipeline, and appropriately open the pressure relief branch regulating valve (44) to depressurize the lead-bismuth storage tank (6) so that the pressure can push the lead-bismuth back into the lead-bismuth storage tank (6); close the argon cylinder 2 (23), close the pressurization branch shut-off valve 1 (21) and pressurization branch shut-off valve 2 (22) on the pressurization branch, and close the pressure relief branch regulating valve (44); Close the pipeline heating cable and heating rod (7), close the main circuit regulating valve (11), and wait for the lead bismuth in the lead bismuth storage tank (6) and the lead bismuth in the test section to cool naturally; cut out the test section (24), and slice the test section (24) for subsequent analysis.

7. The test method of the experimental apparatus for studying particle deposition in high-temperature liquid lead-bismuth according to claim 6, characterized in that, Before the test begins, open the front shut-off valve (20) and the rear shut-off valve (29) of the test section to ensure that the pressure and temperature of all pipes and devices in the circuit are consistent with the external environment when not in the test state.

8. The test method of the experimental apparatus for studying particle deposition in high-temperature liquid lead-bismuth according to claim 6, characterized in that, The test section with wire-wound rod bundle structure is used to simulate particle deposition on reactor core fuel rods. Temperature changes at temperature measuring points can be used to measure the time it takes for particle deposition to reach equilibrium and its impact on heat exchange. Subsequent slicing allows for the study of particle distribution patterns. The rectangular channel test section with a visualization window primarily studies particle deposition behavior at the wall surface. A high-speed camera captures images of particle migration and deposition behavior in the test section for subsequent analysis. When using the visualization test section, as lead-bismuth flows through the visualization window, a high-speed camera captures images of particle deposition distribution and development at the wall surface in the lead-bismuth medium. Data analysis and calculations are then performed. Combined with the vertical narrow rectangular channel particle deposition visualization experiment, the particle movement and deposition patterns in high-temperature lead-bismuth media, as well as the influencing factors on particle migration and deposition patterns within the lead-bismuth fluid, can be obtained. The rectangular channel test section with temperature measuring points can measure the time it takes for particle deposition at the rectangular channel wall to reach equilibrium and its impact on heat exchange.

9. The test method of the experimental apparatus for studying particle deposition in high-temperature liquid lead-bismuth according to claim 6, characterized in that, The effect of gravity on deposition can be obtained by comparing the particle deposition in the test section (24) in the horizontal or vertical state.

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