Pipe body surface boiling scale in-situ testing device and method for simulating reactor core flow channel

Abstract

The invention discloses an in-situ test device and method for simulating boiling scale deposition on the surface of a pipe body of a reactor core runner. The device comprises a test section pipeline, a plurality of tubular samples arranged in an array are inserted in the pipeline, inner heating rods are arranged in the tubular samples, the tubular samples penetrate through sealing pieces at the two ends of the pipeline, and one end of each tubular sample is connected with a pressure regulating device; a plurality of connecting holes are formed in one side of the test section pipeline in the axial direction, the connecting holes are connected with a medium inlet pipeline, a medium outlet pipeline and a plurality of sealing plugs respectively, the sealing plugs comprise at least one visible sealing plug, a laser signal transceiver is arranged outside the visible sealing plug, and the visible sealing plug is connected with a data processing system. And laser emitted by the laser signal transceiver can pass through the window on the visible sealing plug, is reflected by the tubular sample and then returns. The device and the method have obvious advantages in the aspects of authenticity, flexibility and connection reliability of simulated working conditions, and can be fixed for a long time for single test or quick adjustment to adapt to different test purposes.

Description

Technical Field

[0001] The present invention relates to the research field of high-temperature corrosion of metal materials, and in particular to an in-situ testing device and method for boiling fouling on the surface of a tube body simulating a core flow channel. Background Art

[0002] Fuel cladding tubes play a crucial role within the core, the heart of a nuclear reactor. They must not only withstand corrosion from high-temperature, high-pressure water but also effectively conduct the enormous heat released by nuclear reactions. However, during long-term operation, these cladding tubes face two major challenges: first, degradation of thermal conductivity due to fouling, which can cause the tube temperature to rise and accelerate corrosion failure; second, accumulation of boron ions, which can cause localized reductions in reactivity and, in turn, uneven axial power distribution. These phenomena have already caused numerous reactor accidents. Therefore, accurately modeling the deposition behavior of corrosion products on the cladding tube surfaces within the core is crucial for improving reactor operational safety and predicting the cladding's service life.

[0003] Currently, there are three main methods for testing fouling on tubular materials: pinhole accelerated deposition, electromagnetic heating deposition, and internal heating deposition. The pinhole accelerated deposition method accelerates flow by narrowing the flow channel, achieving rapid deposition of corrosion products. However, this method fails to account for surface supercooled nucleate boiling, a key fouling mechanism, and therefore has certain limitations. The electromagnetic heating deposition method utilizes a high-power electromagnetic field to achieve nucleate boiling deposition, but this method is only suitable for nickel-based alloys with moderate conductivity and is not suitable for zirconium alloy cladding tubes. Furthermore, strong electromagnetic fields may interfere with deposition behavior.

[0004] The internal heating deposition method tests the deposition behavior of corrosion products by placing a heating rod inside the tubular specimen, causing the tube surface to be in a supercooled nucleate boiling state, while simultaneously passing flowing high-temperature and high-pressure water. Although this method is currently a relatively excellent testing method, it still has some defects and shortcomings. First, scaling accidents in actual core operation often occur near the grid, and this method fails to consider scaling behavior under complex core flow conditions such as positioning grids, lateral disturbances, and flow-induced vibrations. Secondly, the three existing methods can only take samples for testing after the deposition experiment is completed, and cannot perform in-situ observations, especially cannot obtain real-time, online, and continuous deposition layer growth rates.

[0005] Therefore, it is necessary to propose an in-situ testing device and method for boiling fouling on the tube surface simulating the core flow channel to solve the above technical problems, optimize the design of existing devices, improve the test flexibility and scope of application, so as to ensure reactor safety and extend the life of the cladding tube. Summary of the Invention

[0006] The purpose of the present invention is to provide an in-situ testing device and method for boiling fouling on the surface of a tube body simulating a core flow channel, so as to solve the problem of corrosion product deposition testing of reactor core cladding tubes under subcooled boiling conditions.

[0007] To achieve the above-mentioned purpose, in one aspect, the present invention provides an in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel, comprising a test section pipe, the two ends of the test section pipe are sealed, and a plurality of array-arranged tubular samples are inserted inside, an internal heating rod is provided in the tubular sample, the tubular sample passes through the seals at both ends of the test section pipe, and is connected to a pressure regulating device at one end; a plurality of connecting holes are opened on one side of the test section pipe along its axial direction, each of the connecting holes is respectively connected to a medium inlet pipe, a medium outlet pipe and a plurality of sealing plugs, the sealing plug includes at least one visible sealing plug, a laser signal transceiver is provided on the outside of the visible sealing plug, and the window on the visible sealing plug allows the laser emitted by the laser signal transceiver to pass through and return after being reflected by the tubular sample, and the signal of the laser signal transceiver is connected to a data processing system.

[0008] Optionally, there are 6 connecting holes evenly distributed along the axial direction of the test section pipeline, and each connecting hole is connected to the medium outlet pipeline, medium inlet pipeline 1, visible sealing plug, opening sealing plug, full sealing plug, and medium inlet channel 2 in sequence from top to bottom.

[0009] Optionally, the medium outlet pipe, the medium inlet pipe 1, and the medium inlet channel 2 are all wrapped with a thermal insulation layer, and are all connected to thermocouples extending into the pipes.

[0010] Optionally, a large flow of circulating water is introduced into the second medium inlet channel and the medium outlet pipe to simulate core water circulation, and a small flow of high-temperature and high-pressure water is introduced into the first medium inlet pipe to simulate lateral turbulence.

[0011] Optionally, a spacer grid is connected to the inner hole of the opening sealing plug, and the spacer grid cooperates with each tubular sample arrayed in the test section pipeline to simulate the effect of the spacer in the core on the fouling behavior.

[0012] Optionally, the light-transmitting window in the middle of the visible sealing plug is a diamond window.

[0013] Optionally, both ends of the tubular sample are connected to tubular sample sealing plugs, and a hole is opened in the tubular sample sealing plug at one end and is connected to the pressure regulating device.

[0014] Optionally, the pressure regulating device includes a pressure-maintaining airbag and a high-pressure air pump.

[0015] Optionally, a 4×4 array of tubular samples is inserted inside the test section pipe.

[0016] In another aspect, the present invention provides an in-situ testing method for boiling fouling on the surface of a tube body simulating a core flow channel, the method using any of the above-described in-situ testing devices for boiling fouling on the surface of a tube body simulating a core flow channel, the method comprising the following steps:

[0017] Build a test section pipeline, insert tubular samples, and install internal heating rods in each tubular sample. Determine the position of the positioning grid and the number and type of sealing plugs in the test section pipeline according to experimental requirements to simulate specific working conditions;

[0018] Connect the medium inlet pipe and the medium outlet pipe, and set the temperature and pressure of the medium through the high-temperature and high-pressure water system;

[0019] Install the visual sealing plug and laser signal transceiver to complete the in-situ measurement preparation;

[0020] The pressure equal to that in the test section is injected into the tubular sample through the pressure-maintaining air bag and the high-pressure air pump;

[0021] Start measurement and obtain the operating data of the laser signal transceiver;

[0022] The growth thickness and deposition rate of the deposited layer are analyzed by a data processing system, and the boiling fouling phenomenon on the surface of the tubular sample is evaluated based on this.

[0023] The present invention discloses the following technical effects:

[0024] The present invention presents a device and method for testing boiling fouling on the surface of core flow channel tubes, simulating core flow, providing an efficient and accurate solution for testing corrosion product deposition on nuclear reactor core cladding tubes. The device simulates real-world core operating conditions, including spacer grids, transverse flow disturbances, and flow-induced vibrations, to achieve test results closer to reality. Its multi-component interchangeable design enhances testing flexibility and adaptability, enabling it to meet diverse experimental requirements.

[0025] The device uses a laser signal transceiver and a diamond window to achieve in-situ, online measurement of scale growth thickness on tubular samples, ensuring real-time and accurate data. Furthermore, the combination of a pressure-maintaining airbag and a high-pressure air pump effectively prevents sample creep deformation in high-temperature and high-pressure environments, further ensuring the reliability of the measurement results. By analyzing the growth thickness and deposition rate of the deposited layer through a data processing system, accurate assessment of boiling scale can be achieved, providing a scientific basis for subsequent research and application.

[0026] Compared to existing technologies, this invention offers significant advantages in terms of realistic simulated operating conditions, flexibility, and connection reliability. It can be used for long-term, fixed single tests or rapidly adjusted to suit different testing objectives. These technical benefits not only enhance the ability to test the deposition behavior of corrosion products on nuclear reactor core cladding tubes, but also contribute to improving nuclear reactor operational safety and predicting the service life of cladding, providing important technical support for the safe utilization and sustainable development of nuclear energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a front view of the in-situ testing device for simulating boiling fouling on the surface of a tube body of a core flow channel according to the present invention.

[0029] In the figure: 11, test section pipeline; 12, seal 1; 13, seal 2; 14, tubular sample; 15, internal heating rod; 16, tubular sample sealing plug; 21, medium outlet pipeline; 22, medium inlet pipeline 1; 23, visible sealing plug; 24, opening sealing plug; 25, full sealing plug; 26, medium inlet pipeline 2; 31, positioning grid; 32, thermocouple; 33, insulation layer; 41, laser signal transceiver; 42, data processing system; 43, high-pressure air pump; 44, pressure-maintaining airbag. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Fuel cladding tubes in nuclear reactor cores face fouling and corrosion problems over long periods of operation, leading to reduced thermal conductivity and localized reactivity, compromising safe operation. Existing fouling testing methods include pinhole accelerated deposition, electromagnetic heating deposition, and internal heating deposition, but each has limitations: the pinhole method ignores the nucleate boiling mechanism; the electromagnetic method is unsuitable for zirconium alloys and is subject to electromagnetic interference; and the internal heating method cannot simulate complex core flow conditions and cannot observe the deposition process in situ.

[0032] To address these issues, the present invention proposes a device and method for measuring corrosion product deposition on tubular specimens that can simulate the complex flow path environment of a nuclear core. This allows for flexible reproduction of conditions such as spacer grids, flow-induced vibrations, and lateral turbulence within fuel assemblies. Furthermore, by combining diamond windows, laser ranging technology, and a pressure-maintaining airbag / high-pressure air pump design, the device enables in-situ online measurement of the deposition layer growth rate, accurately determining the corrosion product deposition rate of the fuel cladding tubes. This technology will provide more accurate data support for the safe operation of nuclear reactors and the life prediction of cladding tubes, thereby making a significant contribution to the safe utilization and sustainable development of nuclear energy.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Reference Figure 1 As shown, an embodiment of the present invention provides an in-situ testing device for boiling fouling on the surface of a pipe body simulating a core flow channel, comprising a test section pipe 11. The test section pipe 11 is a hollow structure made of a high-temperature and high-pressure resistant metal material. The upper and lower ends are sealed by metal seals and flanged. The upper end of the test section pipe 11 is a seal 12, and the lower end is a seal 2 13. A plurality of arrayed tubular samples 14 are inserted into the test section pipe 11, and appropriate spacing is maintained between each tubular sample 14 to simulate the flow characteristics in the core flow channel. An internal heating rod 15 is inserted into each tube for internal heating. The heating power is precisely adjusted to place the outer surface of the tubular sample 14 under the condition of supercooled nucleate boiling, thereby simulating the boiling fouling phenomenon of the core flow channel.

[0035] Several circular connection holes are opened on one side of the test section pipe 11, allowing for flexible connection to a variety of interchangeable components based on experimental requirements. In this embodiment, these holes are connected, from top to bottom, to the media outlet pipe 21, media inlet pipe 1 22, visible sealing plug 23, opening sealing plug 24, full sealing plug 25, and media inlet pipe 2 26.

[0036] Fully sealed plugs 25 are used to close unconnected openings, ensuring the tightness of the test section pipe 11. The inner hole of the open hole sealing plug 24 can be used to connect to the spacer grid 31, which is fixed via threaded connecting rods. The spacer grid 31 cooperates with the arrayed tubular samples 14 to simulate the spacers within the core, thereby simulating the influence of the spacers within the core on fouling behavior.

[0037] The visual sealing plug 23 can withstand high temperatures and pressures and provides an online observation window. Specifically, a diamond window is attached to the center of the diamond window plug, providing a channel for laser light to pass through. This allows the laser signal transceiver 41 to face the tubular sample 14 within the window. The laser signal transceiver 41 continuously transmits and receives laser signals, recording the interval between each pulse. The signal is transmitted to the data processing system 42, which filters out the reflected signal from the window and calculates the distance from the sample surface to the transceiver. The change in this distance during the experiment represents the thickness of the deposited layer, and the rate of change represents the deposition rate.

[0038] A diamond window installed on the test section pipe 11, aligned with the laser signal transceiver 41, monitors the scale growth thickness and deposition rate on the surface of the tubular sample 14. A sealing plug at one end of the cladding tube features a connection port for the internal pressure balance system consisting of a pressure-maintaining airbag 44 and a high-pressure air pump 43. This structure effectively prevents sample creep deformation caused by the external high-temperature and high-pressure environment, thereby preventing the laser ranging results from being affected.

[0039] The two medium inlet pipes and the medium outlet pipe 21 are wrapped with a heat insulation layer, and a thermocouple 32 is inserted to ensure that the inlet and outlet medium temperatures of the test section pipe 11 are constant and measurable.

[0040] It should be understood that the medium inlet and outlet pipes can be connected to multiple channels simultaneously to simulate transverse turbulence and flow-induced vibration within the core. In this embodiment, two medium inlet pipes are provided: medium inlet pipe 1 22 and medium inlet pipe 2 26.

[0041] The medium inlet pipe and the medium outlet pipe 21 are connected to the high-temperature and high-pressure water system, and high-temperature water of 310°C and 13.8MPa is introduced. The high-temperature water contains corrosion products of a specified concentration. The pipe is wrapped with an insulation layer 33. Optionally, the insulation layer 33 is made of asbestos insulation material to ensure the temperature stability of the medium during transmission. A thermocouple 32 is inserted into the pipe to monitor the temperature of the inlet and outlet media in real time. The medium pipe can be set to different flow rates according to experimental requirements. Specifically, a large flow of circulating water is introduced into the medium inlet pipe 26 and the medium outlet pipe 21 to simulate the core water circulation; a small flow of high-temperature and high-pressure water is introduced into the medium inlet pipe 1 22 to simulate lateral turbulence.

[0042] By controlling the temperature and pressure of the medium inlet and outlet pipes and the heating power of the internal heating rod 15, the overall temperature and flow rate of the test section pipe 11 and the boiling conditions on the surface of the tubular sample 14 can be controlled; by adjusting the connection between the spacer frame 31 and different sealing plugs, the influence of the spacer frame 31 on the fouling behavior can be tested; by adjusting the number, position and flow rate of the medium inlet pipe and the medium outlet pipe 21, the influence of lateral turbulence and flow-induced vibration on the fouling behavior can be explored.

[0043] Both ends of the tubular sample 14 are connected to tubular sample sealing plugs 16. A hole is opened on the tubular sample sealing plug 16 at one end, which is connected to and connected to the pressure-maintaining airbag 44, and then connected to the high-pressure air pump 43. The internal pressure equal to the pressure of the test section pipeline 11 is filled in the tubular sample 14, thereby avoiding the creep effect caused by the high temperature and high pressure environment outside the tubular sample 14, which causes the tube diameter to change, and then interferes with the laser ranging result.

[0044] In one specific embodiment, a 4×4 array of tubular samples 14 is inserted into the test section pipe 11. Appropriate spacing is maintained between each tubular sample 14 to simulate the flow characteristics of the core flow path. Internal heating rods 15 controlled by a DC power supply are inserted into the tubular samples 14 for internal heating. The heating power is precisely adjusted to maintain a subcooled nucleate boiling state on the outer surface of the tubular samples 14, thereby simulating the boiling fouling phenomenon in the core flow path.

[0045] In a specific embodiment, six threaded connection holes are equidistantly opened on the side of the test section pipe 11, which are respectively connected to the medium outlet pipe 21, the medium inlet pipe 1 22, the visible sealing plug 23, the opening sealing plug 24, the complete sealing plug 25, and the medium inlet pipe 2 26 from top to bottom. By rotating the external tightening nut, pressure is applied to the sealing gasket to ensure high temperature and high pressure tightness.

[0046] In one specific embodiment, the connection holes in the sidewalls of the test section pipe 11 allow for flexible replacement of various components (such as the spacer grid 31, different types of sealing plugs, and media pipes), enabling the device to adapt to a variety of experimental needs. This includes simulation tests of complex operating conditions such as the core spacer grid 31, lateral turbulence, and flow-induced vibration, providing powerful experimental equipment for fouling behavior research. Compared to existing technologies, this test device and test method offer the advantages of realistic simulated operating conditions, strong flexibility, and reliable connections. It can be fixed for long periods of time for single tests, while also allowing for rapid assembly and adjustment based on experimental objectives.

[0047] The present invention realizes real-time, non-contact measurement of the growth thickness and deposition rate of the fouling layer on the surface of the tubular sample 14 through the combination of a laser signal transceiver 41 and a diamond visual sealing plug 23. Compared with traditional offline measurement methods, this device can dynamically reflect the entire process of fouling behavior and provide more accurate experimental data. At present, the accuracy of laser ranging is at the micron level, and the thickness of fouling on the core cladding tube can reach tens of microns, and the influence of high-temperature creep is also at this order of magnitude. The combination of the pressure-maintaining airbag 44 and the high-pressure air pump 43 effectively prevents the creep deformation of the tubular sample 14 caused by the high-temperature and high-pressure environment, avoids the interference of creep on the measurement, and ensures the accuracy of the test results.

[0048] An embodiment of the present invention further provides an in-situ testing method for boiling fouling on the surface of a tube body simulating a core flow channel. The method uses the in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel in the above embodiment, and specifically includes the following steps:

[0049] Build a test section pipeline 11, insert the tubular sample 14, and install an internal heating rod 15 in each tubular sample 14. Determine the position of the spacer grid 31 and the number and type of sealing plugs in the test section pipeline 11 according to experimental requirements to simulate specific working conditions;

[0050] Connect the medium inlet pipe and the medium outlet pipe 21, and set the temperature and pressure of the medium through the high-temperature and high-pressure water system;

[0051] Install the visual sealing plug 23 and the laser signal transceiver 41 to complete the in-situ measurement preparation;

[0052] The pressure equal to that in the test section is injected into the tubular sample 14 through the pressure-maintaining airbag 44 and the high-pressure air pump 43;

[0053] Start measurement and obtain operation data of the laser signal transceiver 41;

[0054] The growth thickness and deposition rate of the deposited layer are analyzed by the data processing system 42 , and the boiling fouling phenomenon on the surface of the tubular sample 14 is evaluated accordingly.

[0055] The in-situ testing device and method for boiling fouling on the surface of a tube body simulating a core flow channel disclosed in the above embodiment are intended to solve the problem of testing corrosion product deposition on nuclear reactor core cladding tubes under subcooled boiling conditions. Compared with the prior art, the device of the present invention provides at least the following beneficial effects:

[0056] 1. Simulate real working conditions: By simulating the complex environment of the core flow channel, including the spacer grid 31, lateral turbulence, flow-induced vibration, etc., the working conditions in the actual core can be simulated more realistically.

[0057] 2. Improved test flexibility: The device design allows for flexible replacement of various components, such as the spacer grid 31, different types of sealing plugs, and media pipes, to meet various experimental requirements.

[0058] 3. Realize in-situ online measurement: Combine the diamond window and the laser signal transceiver 41 to achieve real-time, non-contact measurement of the growth thickness and deposition rate of the scale layer on the surface of the tubular sample 14.

[0059] 4. Improve data accuracy: Through laser ranging technology, the entire process of fouling behavior can be dynamically reflected and more accurate experimental data can be provided.

[0060] 5. Reduce the influence of high temperature creep: The cooperation between the pressure-maintaining airbag 44 and the high-pressure air pump 43 effectively prevents the creep deformation of the tubular sample 14 caused by the high temperature and high pressure environment, thereby avoiding the interference of creep on the measurement.

[0061] 6. Evaluate the boiling fouling phenomenon: The growth thickness and deposition rate of the deposition layer are analyzed by the data processing system 42 to evaluate the boiling fouling phenomenon on the surface of the tubular sample 14 .

[0062] 7. Optimize the design of existing devices: Compared with existing technologies, the present invention has the advantages of realistic simulation of working conditions, strong flexibility, and reliable connection. It can be fixed for a long time for single testing, and can also be quickly assembled and adjusted according to the test purpose.

[0063] 8. Improving the operational safety of nuclear reactors: Accurately simulating and testing the deposition behavior of corrosion products on the surface of cladding tubes can help improve the operational safety of reactors and predict the service life of the cladding.

[0064] Any details not provided in the present invention are all conventional technical means well known to those skilled in the art.

[0065] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0066] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An in-situ testing device for boiling fouling on the surface of a pipe simulating a core flow channel, characterized in that: The invention comprises a test section pipe (11), the two ends of the test section pipe (11) are sealed, and a plurality of arrayed tubular samples (14) are inserted inside the test section pipe, an internal heating rod (15) is provided in the tubular sample (14), the tubular sample (14) passes through the seals at both ends of the test section pipe (11), and is connected to a pressure regulating device at one end; a plurality of connecting holes are opened along the axial direction of one side of the test section pipe (11), each of the connecting holes is respectively connected to a medium inlet pipe, a medium outlet pipe (21) and a plurality of sealing plugs, the sealing plugs include at least one visible sealing plug (23), a laser signal transceiver (41) is provided outside the visible sealing plug (23), a window on the visible sealing plug (23) allows the laser emitted by the laser signal transceiver (41) to pass through and return after being reflected by the tubular sample (14), and the signal of the laser signal transceiver (41) is connected to a data processing system (42).

2. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 1, characterized in that: There are six connecting holes evenly distributed along the axial direction of the test section pipe (11), and each connecting hole is connected to the medium outlet pipe (21), the medium inlet pipe 1 (22), the visible sealing plug (23), the opening sealing plug (24), the full sealing plug (25), and the medium inlet channel 2 in sequence from top to bottom.

3. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 2, characterized in that: The medium outlet pipe (21), the medium inlet pipe 1 (22), and the medium inlet channel 2 are all wrapped with a heat-insulating layer (33), and are all connected to thermocouples (32) extending into the pipes.

4. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 3, characterized in that: The medium inlet channel 2 and the medium outlet pipe (21) are fed with high-flow circulating water to simulate core water circulation, and the medium inlet pipe 1 (22) is fed with low-flow high-temperature and high-pressure water to simulate lateral turbulence.

5. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 2, characterized in that: The inner hole of the opening sealing plug (24) is connected to a positioning grid (31), and the positioning grid (31) cooperates with each tubular sample (14) arranged in an array in the test section pipeline (11) to simulate the influence of the positioning grid in the core on the fouling behavior.

6. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 2, characterized in that: The light-transmitting window in the middle of the visible sealing plug (23) is a diamond window.

7. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 1, characterized in that: Both ends of the tubular sample (14) are connected to tubular sample sealing plugs (16), wherein a hole is opened on the tubular sample sealing plug (16) at one end and is connected to the pressure regulating device.

8. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 7, characterized in that: The pressure regulating device comprises a pressure-maintaining air bag (44) and a high-pressure air pump (43).

9. The in-situ testing device for boiling fouling on the surface of a tube body simulating a core flow channel according to claim 1, characterized in that: A 4×4 array of tubular samples (14) is inserted into the test section pipe (11).

10. An in-situ testing method for boiling fouling on the surface of a pipe body simulating a core flow channel, using the in-situ testing device for boiling fouling on the surface of a pipe body simulating a core flow channel according to any one of claims 1 to 9, characterized in that: The following steps are involved: A test section pipeline (11) is constructed, a tubular sample (14) is inserted, and an internal heating rod (15) is installed in each tubular sample (14). The position of the positioning grid (31) and the number and type of sealing plugs in the test section pipeline (11) are determined according to experimental requirements to simulate specific working conditions; Connecting the medium inlet pipe and the medium outlet pipe (21) to set the temperature and pressure of the medium through a high-temperature and high-pressure water system; Install the visual sealing plug (23) and the laser signal transceiver (41) to complete the in-situ measurement preparation; A pressure equivalent to that in the test section is injected into the tubular sample (14) through a pressure-maintaining air bag (44) and a high-pressure air pump (43); Starting measurement to obtain operation data of the laser signal transceiver (41); The growth thickness and deposition rate of the deposited layer are analyzed by a data processing system (42), and the boiling fouling phenomenon on the surface of the tubular sample (14) is evaluated based on the analysis.

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