A microreactor honeycomb briquette matrix high temperature experimental system and experimental method

Abstract

The present invention discloses a micro-reactor honeycomb coal-like matrix high-temperature experimental system and experimental method, the experimental system includes a main cooling system, an air supply system, a main circuit low-temperature zone before the experimental section, a high-temperature experimental section, a main circuit high-temperature zone after the experimental section, and a pressure vessel cooling system. The main circuit high-temperature zone after the experimental section transfers heat with the main cooling system through a steam-water heat exchanger. The experimental working fluids in the main circuit low-temperature zone before the experimental section, the high-temperature experimental section, and the main circuit high-temperature zone after the experimental section are helium, and the protective working fluid in the high-temperature experimental section is nitrogen, both of which are provided by the air supply system. The cooling working fluids of the main cooling system and the pressure vessel cooling system are both deionized water, which is provided by a cooling water tank. The present invention adopts a high-power DC electric heater to heat the experimental piece, carries out deformation and failure experiments of the honeycomb coal-like matrix under a variety of different working conditions, and completes the heat transfer and mechanical properties research of the honeycomb coal-like matrix under non-uniform load.

Description

Technical Field

[0001] The invention relates to an experimental loop design scheme in the field of micro-reactors, and in particular to a micro-reactor honeycomb coal-shaped matrix high-temperature experimental system and an experimental method. Background Art

[0002] With the continuous expansion of human activities and production space, energy demand in special physical spaces such as the deep sea, deep space, polar regions, and isolated islands is growing rapidly. Nuclear energy offers unparalleled advantages over other energy sources in terms of energy density, reliability, and sustainability, making it the primary energy source of choice for high-intensity exploration and development in special spaces. Microreactors with solid core designs (such as heat pipe reactors and gas-cooled microreactors) have outstanding advantages such as simple reactor structure, high inherent safety characteristics, and ease of modular design and expansion. They are one of the disruptive technologies with the potential to change the future nuclear power landscape and have broad application prospects in scenarios such as deep-sea diving, deep space exploration, and land-based nuclear power sources.

[0003] However, during the transition from cold to hot, hot to cold, power changes, and long-term burnup, solid-state reactors experience significant, complex, and nonuniform geometric deformations due to changes in the power distribution of the fuel elements within the all-solid-state core, as well as thermal expansion and stress deformation due to solid-solid contact. This geometric deformation affects heat transfer from the fuel rods to the cooling channels, further impacting core reactivity and power distribution. Therefore, it is urgent to conduct simulation experiments on the deformation of honeycomb briquette-like substrates under nonuniform loads to reveal the deformation characteristics of the substrate under strong transient thermal shock and its high-temperature creep properties, and to quantitatively evaluate the dynamic deformation of the substrate under in-reactor operating conditions. Since high-temperature and high-pressure experiments are associated with significant risks, to ensure the safety of high-temperature gas experiments, the design of the experimental apparatus should fully consider safety and redundancy criteria. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned existing technical problems and provide a micro-reactor honeycomb coal-like matrix high-temperature experimental system and experimental method, which can simulate the steady-state and transient operating conditions encountered by the honeycomb coal-like matrix (and the supporting tubes) according to the experimental purpose, and is used to evaluate various micro-reactor structural designs and manufacturing materials, and complete the research on the heat transfer performance and deformation characteristics of the micro-reactor core under high temperature and strong transient conditions and the high-temperature creep characteristics, so as to verify the safety of the micro-reactor design concept.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions to implement:

[0006] A micro-reactor honeycomb briquette matrix high-temperature experimental system, including a main cooling system, a main circuit low-temperature zone before the experimental section, a high-temperature experimental section, a main circuit high-temperature zone after the experimental section, a pressure vessel cooling system, and an air supply system:

[0007] The cooling medium of the main cooling system is deionized water, which is provided by the cooling water tank. The main cooling system and the high-temperature zone of the main circuit after the experimental section transfer heat through a steam-water heat exchanger to cool the experimental medium;

[0008] The low-temperature zone of the main circuit before the experimental section is connected to the high-temperature zone of the main circuit after the experimental section through a steam-water heat exchanger, and is connected to the high-temperature experimental section through a flow distributor, and helium is filled in the low-temperature zone of the main circuit before the experimental section;

[0009] The high-temperature experimental section is connected to the low-temperature area of the main circuit in front of the experimental section through a flow distributor, and is connected to the high-temperature area of the main circuit behind the experimental section through a long gas cooling tube. The experimental working fluid in the high-temperature experimental section is helium, which is used to cool the experimental piece, and the protective working fluid is nitrogen, which is provided by the gas supply system to prevent the pipe section from oxidation.

[0010] The high-temperature zone of the main circuit after the experimental section is connected to the high-temperature experimental section through a long gas cooling tube, and is connected to the low-temperature zone of the main circuit before the experimental section through a steam-water heat exchanger. Helium is filled in the high-temperature zone of the main circuit after the experimental section and is filled by the gas supply system before the experiment. The high-temperature zone of the main circuit after the experimental section and the main cooling system transfer heat through the steam-water heat exchanger.

[0011] The main circuit low temperature zone before the experimental section, the high temperature experimental section, and the main circuit high temperature zone after the experimental section are connected to form a main circuit system;

[0012] The cooling medium of the pressure vessel cooling system is deionized water, which is provided by the cooling water tank. The pressure vessel cooling system is directly connected to the double-shell structure of the pressure vessel to ensure that the surface temperature of the pressure vessel is not higher than the room temperature, thus protecting the high-precision detection equipment.

[0013] The gas supply system provides helium as the experimental working medium to the low-temperature zone of the main loop before the experimental section, the high-temperature experimental section, and the high-temperature zone of the main loop after the experimental section, and provides nitrogen as the protective working medium to the high-temperature experimental section.

[0014] In the main cooling system, the cooling water tank 1 is connected to the centrifugal pump 2, the first thermometer 31 and the first pressure transmitter 41 in sequence, and then connected to the first rotary regulating valve 51 and the second rotary regulating valve 52 respectively. The first rotary regulating valve 51 is connected to the first flow meter 61, and the second rotary regulating valve 52 is connected to the second flow meter 62. The cooling medium after the first flow meter 61 and the second flow meter 62 passes through the first check valve 71, and then passes through the steam-water heat exchanger 8, transfers heat with the main circuit system, and then returns to the cooling water tank 1; the centrifugal pump 2 pipe section is provided with a bypass.

[0015] In the low-temperature zone of the main loop before the experimental section, the high-temperature helium is cooled by the steam-water heat exchanger 8, flows through the second thermometer 32, the second pressure transmitter 42 and the third flowmeter 63 in sequence, and then is distributed by the flow distributor 9 to enter the high-temperature experimental section; the loop pipeline adopts a standard 316L stainless steel pipe with a pressure resistance of 25 MPa and a temperature resistance of 800K.

[0016] The high-temperature experimental section includes a pressure vessel 10, a DC electric heater 11 and a test piece 12. The test piece 12 is connected to the high-temperature zone of the main circuit behind the experimental section. The pressure vessel 10 is a double-shell structure and is connected to the protection branch. The pipeline on the pressure vessel 10 is provided with a vacuum pump 14 and a second check valve 72. The test piece 12 is connected to the DC electric heater 11 to provide non-uniform power distribution. The internal measurement parameters of the test piece 12 are temperature, stress, strain and crack size. According to different experimental purposes, it is divided into three parts: steady-state / transient flow heat transfer experiment, matrix mechanical properties experiment and reactor model verification experiment.

[0017] In the high-temperature zone of the main loop after the experimental section, helium is supplied through a primary gas supply branch. The gas preheater 15 is turned on only when the main loop system is started to heat the helium to 600K to ensure that the heat transfer performance of the experimental section simulates the actual working conditions. During the formal experiment, the gas preheater 15 pipe section is in a closed state and the bypass is opened. In the high-temperature experiment, the helium flowing out of the high-temperature experimental section has a high temperature. It first passes through a long gas cooling tube 13 to achieve convection heat dissipation from high-temperature gas to room temperature air, and then is measured by a third thermometer 33, a third pressure transmitter 43 and a fourth flowmeter 64, and finally passes through a steam-water heat exchanger 8. The loop pipeline adopts a standard 316L stainless steel pipe with a pressure bearing capacity of 25MPa and a temperature resistance of 800K.

[0018] The gas supply system includes a primary gas supply branch and a protective branch. A third rotary regulating valve 53 and a first safety valve 181 are installed at the interface between the primary gas supply branch, which is connected in parallel with the helium cylinder 16 and the main circuit high-temperature zone pipeline after the experimental section. Helium gas with a stable high inlet pressure is provided as the gaseous experimental working medium through the parallel helium cylinder 16. A fourth rotary regulating valve 54 and a second safety valve 182 are installed at the interface between the protective branch, which is connected to the nitrogen cylinder 17 and the pipeline. Nitrogen gas is supplied to the pressure vessel 10 through the nitrogen cylinder 17 to maintain the actual pressure within the pressure vessel 10 higher than the maximum pressure within the experimental piece 12, preventing leakage of experimental gas and protecting the experimental piece from oxidation at high temperatures.

[0019] In the pressure vessel cooling system, the cooling water tank 1 is directly connected to the double-shell structure of the pressure vessel 10 and provides cooling to protect high-precision detection equipment.

[0020] The experimental method of the micro-reactor honeycomb briquette matrix high temperature experimental system comprises the following steps:

[0021] 1) Before starting the experiment, check whether the valves of the experimental device are open, whether the instruments are in good condition, whether the gas supply system has sufficient gas, and ensure that the pipes before and after the experimental piece 12 are flowing freely to avoid pressurizing the experimental piece 12;

[0022] 2) starting the vacuum pump 14 to evacuate the pressure vessel 10;

[0023] 3) introducing nitrogen to fill the pressure vessel 10;

[0024] 4) Adjust the pressure of the vacuum pump 14 and the nitrogen bottle 17 to maintain the pressure in the pressure vessel 10 basically stable;

[0025] 5) Introduce inert gas into the main circuit system to exhaust the air in the main circuit system;

[0026] 6) Open the third rotary regulating valve 53 and the first safety valve 181, introduce helium into the high-temperature area of the main loop after the experimental section for a period of time, and check the readings of the third flow meter 63 and the fourth flow meter 64 to prevent gas leakage;

[0027] 7) Turn on the gas preheater 15, slowly increase the helium temperature in the main loop system, and check the readings of the second thermometer 32 and the third thermometer 33;

[0028] 8) When the helium temperature exceeds 600K, the gas preheater 15 is closed and the gas preheater 15 pipe section is opened for bypass;

[0029] 9) Start centrifugal pump 2 and check the sealing of the main cooling system;

[0030] 10) Adjust the centrifugal pump 2 and check the readings of the first flow meter 61 and the second flow meter 62;

[0031] 11) Under the condition that there is no helium leakage, a low-temperature heat transfer experiment is carried out, the average temperature of the substrate does not exceed 900K, and the readings of the first flow meter 61 and the second flow meter 62 are calibrated;

[0032] 12) Gradually increase the power of the DC heating device 11, repeat experimental step 6, and monitor the stability of the experimental system;

[0033] 13) After the power is increased to the specified power and the average temperature of the substrate reaches the experimental requirements, continue to observe for a period of time. After all parameters are stable, conduct heat transfer experiments and substrate mechanical properties experiments;

[0034] 14) After the experiment, maintain the power of the centrifugal pump 2 and slowly reduce the power of the DC electric heater 11 to achieve slow cooling and avoid damage to the experimental parts;

[0035] 15) After the power of the DC electric heater 11 drops to 0, the experimental gas is continuously introduced to remove the residual heat of the main circuit system;

[0036] 16) After the experimental system has completely cooled, continue to introduce inert gas to exhaust the experimental gas. After repeating this process several times, close the pipeline valve to keep the experimental pipeline airtight.

[0037] 17) The vacuum pump 14 is turned on to maintain the pressure vessel 10 at normal pressure;

[0038] 18) At the end of the experiment, collect data and turn off the power of the centrifugal pump 2, vacuum pump 14 and collection box;

[0039] 19) Replace the experimental piece and repeat the above process.

[0040] The present invention has the following advantages and beneficial effects:

[0041] 1. Several branches in the loop can be combined with the experimental section connection points to expand the required experimental pieces 12 according to specific experimental needs. For different types of microreactors, such as heat pipe reactors, gas-cooled microreactors (pebble bed type or prismatic type), etc., the experimental section can be modified according to their cooling methods to carry out steady-state / transient flow heat transfer experiments, matrix mechanical properties experiments and reactor model verification experiments to test and evaluate the reliability and safety performance of different types of microreactors.

[0042] 2. The experimental section is placed in a pressure vessel 10 and is supplied with nitrogen as the ambient gas to maintain the actual pressure in the pressure vessel 10 higher than the maximum pressure in the experimental piece 12. This prevents helium leakage in the coolant flow channel due to loose contact between the experimental piece and the helium delivery pipeline.

[0043] 3. The DC electric heater 10 is used to heat the components in different zones and control the power distribution in different zones.

[0044] 4. A longer non-insulated pipe is added to the high-temperature main loop system after the experimental section. The convection heat dissipation between high-temperature gas and room temperature air is used to cool the high-temperature gas at the outlet 12 of the experimental piece to meet the operating temperature of the measuring instruments in the rear section, which is convenient for experimental data collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a working principle diagram of the micro-reactor honeycomb coal-shaped matrix high-temperature experimental system of the present invention.

[0046] In the figure: 1, cooling water tank 2, centrifugal pump 31, first thermometer 32, second thermometer 33, third thermometer 41, first pressure transmitter safety valve 42, second pressure transmitter 43, third pressure transmitter 51, first rotary regulating valve 52, second rotary regulating valve 53, third rotary regulating valve 54, fourth rotary regulating valve 61, first flowmeter 62, second flowmeter 63, third flowmeter 64, fourth flowmeter 71, first check valve 72, second check valve 8, steam-water heat exchanger 9, flow distributor 10, pressure vessel 11, DC electric heater 12, test piece 13, gas cooling long tube 14, vacuum pump 15, gas preheater 16, helium storage tank 17, nitrogen cylinder 181, first safety valve 182, second safety valve DETAILED DESCRIPTION

[0047] The method of the present invention is further described in detail below with reference to the accompanying drawings:

[0048] like Figure 1 As shown, the present invention provides a micro-reactor honeycomb briquette matrix high-temperature experimental system, including a main cooling system, a main circuit low-temperature zone before the experimental section, a high-temperature experimental section, a main circuit high-temperature zone after the experimental section, a pressure vessel cooling system, and an air supply system:

[0049] The main circuit low temperature zone before the experimental section, the high temperature experimental section, and the main circuit high temperature zone after the experimental section are connected to form a main circuit system;

[0050] In the main cooling system, the cooling water tank 1 is connected to the centrifugal pump 2, the first thermometer 31 and the first pressure transmitter 41 in sequence, and then connected to the first rotary regulating valve 51 and the second rotary regulating valve 52 respectively. The first rotary regulating valve 51 is connected to the first flow meter 61, and the second rotary regulating valve 52 is connected to the second flow meter 62. The cooling medium after the first flow meter 61 and the second flow meter 62 passes through the first check valve 71, and then passes through the steam-water heat exchanger 8, transfers heat with the main loop system, and then returns to the cooling water tank 1. The parallel flow meter design ensures higher detection accuracy; the centrifugal pump 2 pipe section is provided with a bypass to ensure that the experimental system will not lose cooling under accident conditions.

[0051] In the low-temperature zone of the main loop before the experimental section, the high-temperature helium is cooled by the steam-water heat exchanger 8, flows through the second thermometer 32, the second pressure transmitter 42, and the third flowmeter 63 in sequence, and is then distributed by the flow distributor 9 to enter the high-temperature experimental section; the loop pipeline adopts a standard 316L stainless steel pipe with a pressure resistance of 25 MPa and a temperature resistance of 800K; in order to simulate the cooling form of multiple cooling channels in the core, it is necessary to use the flow distributor 9 to ensure uniform flow distribution in each cooling channel.

[0052] The high-temperature experimental section includes a pressure vessel 10, a DC electric heater 11 and a test piece 12. The test piece 12 is connected to the high-temperature zone of the main circuit behind the experimental section. The pressure vessel 10 is a double-shell structure and is connected to the protection branch. The pipeline on the pressure vessel 10 is provided with a vacuum pump 14 and a second check valve 72. The test piece 12 is connected to the DC electric heater 11 to simulate the uneven power distribution of an actual reactor. The internal measurement parameters of the test piece 12 are temperature, stress, strain and crack size. According to different experimental purposes, it is divided into three parts: steady-state / transient flow heat transfer experiment, matrix mechanical properties experiment and reactor model verification experiment. In order to prevent heat loss, a high-temperature resistant insulating and heat-preserving coating needs to be applied to the test piece 12. A window is opened on the surface of the pressure vessel 10 to ensure that the state of the test piece 12 can be observed in real time during the experiment. To ensure experimental safety, the transparent material on the surface of the pressure vessel 10 is quartz glass.

[0053] In the high-temperature zone of the main loop after the experimental section, helium is supplied through a primary loop gas supply branch, and the gas preheater 15 is turned on only when the main loop system is started, and is used to heat the helium to 600K to ensure that the heat transfer performance of the experimental section simulates the actual working conditions. During the formal experiment, the gas preheater 15 pipe section is in a closed state and the bypass is opened; in the high-temperature experiment, the helium flowing out of the high-temperature experimental section has a high temperature, and first passes through a gas cooling long tube 13, and then is measured by a third thermometer 33, a third pressure transmitter 43 and a fourth flowmeter 64, and finally passes through a steam-water heat exchanger 8; the loop pipeline adopts a standard 316L stainless steel pipe with a pressure bearing capacity of 25MPa and a temperature resistance of 800K; the gas cooling long tube 13 adopts a high-temperature resistant and high-thermal conductivity material, such as tungsten, to achieve convection heat dissipation of high-temperature gas-room temperature air, cool the gas, and facilitate data collection;

[0054] The gas supply system includes a primary gas supply branch and a protection branch. A third rotary regulating valve 53 and a first safety valve 181 are provided at the interface between the primary gas supply branch, which is connected in parallel with the helium cylinder 16 and the pipeline in the high-temperature zone of the main circuit after the experimental section. Stable helium with a high inlet pressure is provided as a gas experimental working medium through the parallel helium cylinder 16; a fourth rotary regulating valve 54 and a second safety valve 182 are provided at the interface between the protective branch, which is connected to the nitrogen cylinder 17 and the pipeline. Nitrogen is provided to the pressure vessel 10 through the nitrogen cylinder 17 to maintain the actual pressure in the pressure vessel 10 higher than the maximum gas pressure in the experimental piece 12, prevent the experimental gas from leaking, and protect the experimental piece from being oxidized at high temperatures.

[0055] In the pressure vessel cooling system, the cooling water tank 1 is directly connected to the double-shell structure of the pressure vessel 10 and provides cooling to protect high-precision detection equipment.

[0056] The experimental method of the micro-reactor honeycomb briquette matrix high temperature experimental system comprises the following steps:

[0057] 1) Before starting the experiment, check whether the valves of the experimental device are open, whether the instruments are in good condition, whether the gas supply system has sufficient gas, and ensure that the pipes before and after the experimental piece 12 are flowing freely to avoid pressurizing the experimental piece 12;

[0058] 2) starting the vacuum pump 14 to evacuate the pressure vessel 10;

[0059] 3) Nitrogen is introduced to fill the pressure vessel 10 completely. Ensure that the actual pressure within the pressure vessel 10 is higher than the maximum pressure within the test piece 12, typically 30 kPa higher. This prevents helium leakage from the coolant flow path due to loose contact between the test piece and the helium delivery pipeline. This also removes some of the heat dissipated by the heated test piece, providing a cooling effect.

[0060] 4) Adjust the pressure of the vacuum pump 14 and the nitrogen bottle 17 to maintain the pressure in the pressure vessel 10 basically stable;

[0061] 5) Introduce inert gas into the main circuit system to exhaust the air in the main circuit system to prevent pipeline oxidation under high temperature conditions;

[0062] 6) Open the third rotary regulating valve 53 and the first safety valve 181, and introduce helium into the high-temperature area of the main circuit after the experimental section for a period of time. Verify the readings of the third flow meter 63 and the fourth flow meter 64 to ensure that the flow rates are the same to prevent gas leakage;

[0063] 7) Under the condition that there is no helium leakage, open the gas preheater 15, slowly increase the helium temperature in the main loop system, and calibrate the readings of the second thermometer 32 and the third thermometer 33;

[0064] 8) When the helium temperature exceeds 600K, the gas preheater 15 is closed and the gas preheater 15 pipe section is opened for bypass;

[0065] 9) Start centrifugal pump 2 and check the sealing of the main cooling system, focusing on observing whether there is any leakage at the interface of each pipe section;

[0066] 10) Adjust the centrifugal pump 2 and check the readings of the first flow meter 61 and the second flow meter 62 to ensure that the cooling medium flow rate meets the experimental requirements;

[0067] 11) Under the condition that there is no helium leakage, a low-temperature heat transfer experiment is carried out, the average temperature of the substrate does not exceed 900K, and the readings of the first flow meter 61 and the second flow meter 62 are calibrated;

[0068] 12) Gradually increase the power of the DC heating device 11 and repeat experimental step 6, monitoring the stability of the experimental system while observing the state of the test piece 12 through the window of the pressure vessel 10;

[0069] 13) After the power is increased to the specified power and the average temperature of the substrate reaches the experimental requirements, continue to observe for a period of time. After all parameters are stable, conduct heat transfer experiments and substrate mechanical properties experiments;

[0070] 14) After the experiment, maintain the power of the centrifugal pump 2 and slowly reduce the power of the DC electric heater 11 to achieve slow cooling and avoid damage to the experimental parts;

[0071] 15) After the power of the DC electric heater 11 drops to 0, the experimental gas is continuously introduced to remove the residual heat of the main circuit system;

[0072] 16) After the experimental system has completely cooled, continue to introduce inert gas to exhaust the experimental gas. After repeating this process several times, close the pipeline valve to keep the experimental pipeline airtight.

[0073] 17) The vacuum pump 14 is turned on to maintain the pressure of the pressure vessel 10 equal to the ambient pressure;

[0074] 18) At the end of the experiment, collect data and turn off the power of the centrifugal pump 2, vacuum pump 14 and collection box;

[0075] 19) Replace the experimental piece and repeat the above process.

Claims

1. A micro-reactor honeycomb briquette matrix high temperature experimental system, characterized in that: It includes the main cooling system, the low-temperature zone of the main circuit before the experimental section, the high-temperature experimental section, the high-temperature zone of the main circuit after the experimental section, the pressure vessel cooling system and the air supply system: The cooling medium of the main cooling system is deionized water, which is provided by the cooling water tank. The main cooling system and the high-temperature zone of the main circuit after the experimental section transfer heat through a steam-water heat exchanger to cool the experimental medium; The low-temperature zone of the main circuit before the experimental section is connected to the high-temperature zone of the main circuit after the experimental section through a steam-water heat exchanger, and is connected to the high-temperature experimental section through a flow distributor, and helium is filled in the low-temperature zone of the main circuit before the experimental section; The high-temperature experimental section is connected to the low-temperature area of the main circuit in front of the experimental section through a flow distributor, and is connected to the high-temperature area of the main circuit behind the experimental section through a long gas cooling tube. The experimental working fluid in the high-temperature experimental section is helium, which is used to cool the experimental piece, and the protective working fluid is nitrogen, which is provided by the gas supply system to prevent the pipe section from oxidation. The high-temperature zone of the main circuit after the experimental section is connected to the high-temperature experimental section through a long gas cooling tube, and is connected to the low-temperature zone of the main circuit before the experimental section through a steam-water heat exchanger. Helium is filled in the high-temperature zone of the main circuit after the experimental section and is filled by the gas supply system before the experiment. The high-temperature zone of the main circuit after the experimental section and the main cooling system transfer heat through the steam-water heat exchanger. The main circuit low temperature zone before the experimental section, the high temperature experimental section, and the main circuit high temperature zone after the experimental section are connected to form a main circuit system; The cooling medium of the pressure vessel cooling system is deionized water, which is provided by the cooling water tank. The pressure vessel cooling system is directly connected to the double-shell structure of the pressure vessel to ensure that the surface temperature of the pressure vessel is not higher than the room temperature, thus protecting the high-precision detection equipment. The gas supply system provides helium as the experimental working medium for the low-temperature zone of the main circuit before the experimental section, the high-temperature experimental section, and the high-temperature zone of the main circuit after the experimental section, and provides nitrogen as the protective working medium for the high-temperature experimental section; The high-temperature experimental section includes a pressure vessel, a DC electric heater, and a test piece. The test piece is connected to the high-temperature zone of the main circuit behind the experimental section. The pressure vessel has a double-shell structure and is connected to the protection branch. The pipeline on the pressure vessel is equipped with a vacuum pump and a second check valve. The test piece is connected to the DC electric heater to provide non-uniform power distribution. The internal measurement parameters of the test piece are temperature, stress, strain, and crack size. Depending on the experimental purpose, it is divided into three parts: steady-state or transient flow and heat transfer experiments, matrix mechanical properties experiments, and reactor model verification experiments. The gas supply system includes a primary gas supply branch and a protection branch. A third rotary regulating valve and a first safety valve are provided at the interface between the parallel helium cylinder of the primary gas supply branch and the pipeline in the high-temperature zone of the main circuit after the experimental section. A fourth rotary regulating valve and a second safety valve are provided at the interface between the nitrogen cylinder of the protection branch and the pipeline. Nitrogen is supplied to the pressure vessel through the nitrogen cylinder to maintain the actual pressure in the pressure vessel higher than the maximum gas pressure in the experimental piece, prevent the experimental gas from leaking, and protect the experimental piece from oxidation at high temperature.

2. The micro-reactor honeycomb briquette matrix high temperature experimental system according to claim 1, characterized in that: In the main cooling system, the cooling water tank (1) is connected to the centrifugal pump (2), the first thermometer (31) and the first pressure transmitter (41) in sequence, and then respectively connected to the first rotary regulating valve (51) and the second rotary regulating valve (52). The first rotary regulating valve (51) is connected to the first flow meter (61), and the second rotary regulating valve (52) is connected to the second flow meter (62). The cooling medium after the first flow meter (61) and the second flow meter (62) passes through the first check valve (71), and then passes through the steam-water heat exchanger (8), transfers heat with the main circuit system, and then returns to the cooling water tank (1); the centrifugal pump (2) pipe section is provided with a bypass.

3. The micro-reactor honeycomb briquette matrix high temperature experimental system according to claim 2, characterized in that: In the low-temperature zone of the main loop before the experimental section, the high-temperature helium is cooled by the steam-water heat exchanger (8), flows through the second thermometer (32), the second pressure transmitter (42) and the third flow meter (63) in sequence, and then is distributed by the flow distributor (9) to enter the high-temperature experimental section; the loop pipeline adopts a standard 316L stainless steel pipe with a pressure bearing capacity of 25MPa and a temperature resistance of 800K.

4. The micro-reactor honeycomb briquette matrix high temperature experimental system according to claim 3, characterized in that: In the high-temperature zone of the main circuit after the experimental section, helium is supplied through a loop gas supply branch, and the gas preheater (15) is only turned on when the main circuit system is started, and is used to heat the helium to 600K to ensure that the heat transfer performance of the experimental section simulates the actual working conditions. During the formal experiment, the gas preheater (15) pipe section is in a closed state and the bypass is opened; in the high-temperature experiment, the temperature of the helium flowing out of the high-temperature experimental section is high, and it first passes through a gas cooling long pipe (13) to achieve convection heat dissipation of high-temperature gas-room temperature air, and then is measured by a third thermometer (33), a third pressure transmitter (43) and a fourth flowmeter (64), and finally passes through a steam-water heat exchanger (8); the loop pipeline adopts a standard 316L stainless steel pipe with a pressure bearing capacity of 25MPa and a temperature resistance of 800K.

5. The micro-reactor honeycomb briquette matrix high temperature experimental system according to claim 4, characterized in that: Helium gas with a stable high inlet pressure is provided as a gaseous experimental working medium by a parallel helium gas cylinder (16).

6. The micro-reactor honeycomb briquette matrix high temperature experimental system according to claim 5, characterized in that: In the pressure vessel cooling system, the cooling water tank (1) is directly connected to the double-shell structure of the pressure vessel (10) and provides cooling to protect high-precision detection equipment.

7. The experimental method of the micro-reactor honeycomb briquette matrix high temperature experimental system according to claim 6, characterized in that: The following steps are involved: 1) Before the experiment begins, check whether the valves of the experimental device are open, whether the status of the instruments is intact, whether the gas volume of the gas supply system is sufficient, and ensure that the pipelines before and after the experimental piece (12) are flowing to avoid the experimental piece (12) being under pressure; 2) starting the vacuum pump (14) to evacuate the pressure vessel (10); 3) introducing nitrogen to fill the pressure vessel (10); 4) Adjust the pressure of the vacuum pump (14) and the nitrogen bottle (17) to maintain the pressure in the pressure vessel (10) basically stable; 5) Introduce inert gas into the main circuit system to exhaust the air in the main circuit system; 6) Open the third rotary regulating valve (53) and the first safety valve (181), introduce helium into the high temperature area of the main circuit after the experimental section for a period of time, and calibrate the readings of the third flow meter (63) and the fourth flow meter (64). Prevent gas leakage; 7) Turn on the gas preheater (15), slowly increase the helium temperature in the main loop system, and check the readings of the second thermometer (32) and the third thermometer (33); 8) When the helium temperature exceeds 600K, the gas preheater (15) is closed and the gas preheater (15) pipe section is opened for bypass; 9) Start the centrifugal pump (2) and check the tightness of the main cooling system; 10) Adjust the centrifugal pump (2) and calibrate the readings of the first flow meter (61) and the second flow meter (62); 11) Under the condition that there is no helium leakage, a low-temperature heat transfer experiment is carried out, the average temperature of the substrate does not exceed 900K, and the readings of the first flow meter (61) and the second flow meter (62) are calibrated; 12) Gradually increase the power of the DC heating device (11), repeat experimental step 6, and monitor the stability of the experimental system; 13) After the power is increased to the specified power and the average temperature of the substrate reaches the experimental requirements, continue to observe for a period of time. After all parameters are stable, heat transfer experiments and matrix mechanical properties experiments are carried out; 14) After the experiment is completed, the power of the centrifugal pump (2) is maintained, and the power of the DC electric heater (11) is slowly reduced to achieve slow cooling and avoid damage to the experimental parts; 15) After the power of the DC electric heater (11) drops to 0, the experimental gas is continuously introduced to remove the residual heat of the main circuit system; 16) After the experimental system has completely cooled, continue to introduce inert gas to exhaust the experimental gas. After repeating this process several times, close the pipeline valve to keep the experimental pipeline airtight. 17) The vacuum pump (14) is turned on to maintain the pressure vessel (10) at normal pressure; 18) At the end of the experiment, collect data and turn off the centrifugal pump (2), vacuum pump (14) and collection box power supply; 19) Replace the experimental piece and repeat the above process.

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