An experimental research system for pressurized water reactor regenerative heat exchangers

Abstract

The invention discloses a test research system suitable for a pressurized water reactor regenerative heat exchanger, comprising a water source control system, a pressure control system and a test loop of the regenerative heat exchanger, wherein the water source control system and the pressure control system are both connected to the test loop, the water source control system is used for filling the test loop with water before the test and filling the test with water during the test, and the pressure control system increases the coolant pressure in the test loop by filling gas; the test loop comprises a flow control system, a heating system and an auxiliary heat recovery system, the flow control system can control and adjust the flow in the test loop and input the flow into the heating system, the heating system comprises a regenerative heat exchanger, the heating system can heat the coolant in the test loop to a target temperature and then input the coolant into the shell side of the regenerative heat exchanger, the auxiliary heat recovery system provides cooling water of a specified temperature for the tube side of the regenerative heat exchanger, and the cooling water is cooled by the action of a cooling tower.

Description

Technical Field

[0001] The invention relates to the test field of a pressurized water reactor regenerative heat exchanger, and in particular to a test research system suitable for a pressurized water reactor regenerative heat exchanger. Background Art

[0002] In the pressurized water reactor nuclear power system, the regenerative heat exchanger is mostly a U-shaped shell and tube heat exchanger: the shell side inlet nozzle is connected to the downflow pipeline of the reactor's primary circuit, and the high-temperature fluid in the primary circuit flows through the shell side of the regenerative heat exchanger to the downstream downflow heat exchanger and the chemical volume water tank; the tube side inlet nozzle is connected to the outlet of the chemical volume pump, and the coolant is injected into the reactor's primary circuit's charging pipeline from the tube side of the regenerative heat exchanger. Similar to applications in other energy fields, the design of the regenerative heat exchanger in the nuclear energy field is also to achieve the purpose of recovering the heat of the downflow fluid and preheating the charging fluid.

[0003] Scholars in the industry have conducted a series of experimental studies and scheme designs related to regenerative heat exchangers. For example, patent CN213933528U proposed the design of "a high-temperature and high-flow rate droplet erosion experimental device". The device includes steam generators, regenerative heat exchangers, coolers, high-pressure pumps, water chemical control systems, upper filling pipes, and lower discharge pipes corresponding to nuclear power systems. It can perform droplet erosion experiments under high temperature and high pressure environments, and can adjust the impact angle, impact speed, gas content, and water chemical parameters to obtain experimental results in a wide range. For example, patent CN110265166A proposed an optimized design scheme for "a chemical and volume control system for a boron-free pressurized water reactor nuclear power plant", which uses a high separation rate membrane to remove nuclides and impurities, reduces the use of resin beds and filters, reduces the amount of radioactive solid waste generated and the radiation dose received by personnel during the replacement process, and avoids the use of hydrogen, reduces the dangerous sources of nuclear power plants, and simplifies personnel operations. For example, patent CN111564232A proposes an optimized design scheme for "a method and device for transient control of RCV system in a nuclear power plant", which queries the target flow rate and valve opening time based on the temperature difference between the upper filling fluid temperature of the regenerative heat exchanger and the preset temperature value, thereby preventing the occurrence of severe transients.

[0004] When conducting fatigue and life analysis tests on regenerative heat exchangers in the laboratory, it was found that the test equipment currently introduced publicly was mainly based on the prototype design of the nuclear power system, and had the following shortcomings for laboratory research: (1) The pressure control system uses an electric heating rod to heat the cooling water to generate steam pressure. The pressure increase speed of this control method is severely limited by the heating power and is relatively slow; (2) The flow control system has a large flow control span within the range and needs to control the pump or valve based on debugging experience. The flow control is not accurate enough and is difficult to adjust; (3) The heating system uses a high-power heater to heat the test loop cooling water. Too many heaters need to be configured and the initial preheating time is long; (4) The loop cooling water of the cooling regenerative heat exchanger test section is directly cooled to the air cooling tower, without auxiliary heat recovery utilization, and the thermal expansion cooling water needs to be discharged during the heating and pressure increase process, resulting in energy waste; (5) The pressure of the test system is too high and the test loop cooling water is not deoxygenated or filtered. After the cooling water is discharged, there is a small amount of cooling water remaining in the test pipeline, which causes corrosion and rusting of the test loop pipeline, reducing the service life of the system and posing a high potential risk.

[0005] In view of the above technical problems, the present invention is specially introduced. Summary of the invention

[0006] The main purpose of the present invention is to provide a test research system suitable for a pressurized water reactor regenerative heat exchanger to solve the above problems existing in the prior art.

[0007] In order to achieve the above-mentioned purpose, the present invention proposes a test research system suitable for a pressurized water reactor regenerative heat exchanger, comprising a water source control system, a pressure control system and a test loop of the regenerative heat exchanger, wherein the water source control system and the pressure control system are both connected to the test loop, the water source control system is used to fill the test loop with water before the test and to fill the test loop with water during the test, and the pressure control system increases the coolant pressure in the test loop by filling gas;

[0008] The test loop includes a flow control system, a heating system and an auxiliary heat recovery system. The flow control system can control and adjust the flow in the test loop and input it into the heating system. The heating system includes a regenerative heat exchanger. The heating system can heat the coolant in the test loop to the target temperature and then input it into the shell side of the regenerative heat exchanger. The auxiliary heat recovery system provides cooling water of a specified temperature to the tube side of the regenerative heat exchanger, and the cooling water is cooled by the cooling tower.

[0009] Furthermore, the flow control system includes a first flow regulating pipeline and a second flow regulating pipeline which are arranged in parallel and have different ranges. The first flow regulating pipeline and the second flow regulating pipeline are both provided with a flow regulating valve, a flow meter and a variable frequency pump.

[0010] Furthermore, the flow control system includes a flow controller, and the control formula of the flow controller is: Q1=k×f+c, wherein k and c are constants determined according to a debugging test, and f is the operating frequency of the variable frequency pump.

[0011] Furthermore, the flow control system performs flow control on the test loop. First, the frequency of the variable frequency pump is adjusted according to the control logic of the flow controller so that the relationship between the actual flow Q1 and the target flow Q is: Q1=Q(1+2%~5%), and then the flow regulating valve is fine-tuned to obtain the target flow Q.

[0012] Furthermore, the upper range limit of the first ultrasonic flowmeter on the first flow regulating pipeline is 40t / h≤L1≤50t / h, and the upper range limit of the second ultrasonic flowmeter on the second flow regulating pipeline is 15t / h≤L2≤25t / h, and the range ratio is 10:1.

[0013] Furthermore, a plate heat exchanger is connected between the first flow regulating pipeline and the second flow regulating pipeline. The two shell sides of the plate heat exchanger are respectively connected to the first flow regulating pipeline and the second flow regulating pipeline through pipelines with electric regulating valves, and the pipe side of the plate heat exchanger is connected to the cooling tower.

[0014] Furthermore, the heating system includes a main heating pipeline, on which a regenerative heat exchanger and an auxiliary heat regenerator are provided. The auxiliary heat regenerator is located downstream of the regenerative heat exchanger, and the auxiliary heat regenerator pipeline of the auxiliary heat regenerator system includes the tube side of the regenerative heat exchanger and the tube side of the auxiliary heat regenerator.

[0015] Furthermore, the auxiliary heat recovery pipeline is an independent loop, and also includes a circulation pump, a shell side of the auxiliary heat exchanger and a third ultrasonic flowmeter, and the tube side of the auxiliary heat exchanger is connected to the cooling tower.

[0016] Furthermore, a main heater and a heat storage tank are provided on the main heating pipeline. The heat storage tank is located downstream of the main heater, and the regenerative heat exchanger is located downstream of the heat storage tank. The heat storage tank includes a mixer and a temperature controller, which can distribute the coolant in the test loop and the stored water in the heat storage tank, and control the coolant temperature at the heat storage tank outlet to reach the target temperature.

[0017] Furthermore, the pressure control system includes a gas compressor, a buffer tank, a pressure stabilizing tank and an overflow tank which are connected in sequence, and the overflow tank is respectively connected to the top, bottom and middle of the pressure stabilizing tank in the height direction.

[0018] Furthermore, the volume V1 of the buffer tank and the volume V2 of the surge tank satisfy: V1=V2, and the volume V3 of the overflow tank and the volume V0 of the coolant in the experimental research system satisfy V3≥0.3V0.

[0019] Furthermore, the water source control system includes a water supply pipeline and a water source box. The water supply pipeline includes a water supply pump, a deaerator and a filter. The end of the water supply pipeline is connected to the water source box. The water source box is located at the maximum elevation of the experimental research system.

[0020] Furthermore, the water source control system also includes a normal pressure water supply pipeline and a high pressure water replenishment pipeline arranged between the water source tank and the test loop. The normal pressure water supply pipeline is used for filling water before the test, and the high pressure water replenishment pipeline includes a volume control pump and a fourth ultrasonic flow meter, which is used for water replenishment during the test.

[0021] Furthermore, the experimental research system includes an upstream confluence pipeline, part of which is connected between the upstream of the flow control system and the downstream of the heating system, constituting a part of the test loop, and the pressure control system and the water source control system are both connected to the upstream confluence pipeline.

[0022] Furthermore, the pressure bearing capacity of each part of the pipeline of the experimental research system is not less than 8.6MPa, and the temperature resistance is not less than 300℃.

[0023] By applying the technical solution of the present invention, at least the following beneficial effects are achieved:

[0024] 1. The experimental research system of the present invention adopts a gas pressurization method with stable chemical properties to replace the method of using electric heating rods to heat cooling water to generate steam pressurization in terms of pressure control, so that the pressurization response speed is greatly improved, and the experimental research of the pressurized water reactor regenerative heat exchanger can be completed efficiently.

[0025] 2. The experimental research system of the present invention realizes more precise control of the flow by designing the structure of the flow control system and the flow control method, adopting a model in which large-flow and small-flow pipelines work together and the flow controller cooperates with the frequency conversion pump, electric regulating valve, etc. for adjustment.

[0026] 3. The test research system of the present invention reduces the discharge of high-temperature cooling water during the heating process of the test loop by designing an overflow box; by designing a heat storage box and adopting a mode in which the heater and the preheater work together, the preheating cycle and the number of heaters configured are greatly shortened; by designing auxiliary heat recovery pipes and auxiliary heat recovery devices, the heat loss during the test is reduced, thereby greatly reducing the test cost, reducing energy waste, and having good economic benefits.

[0027] 4. The test and research system of the present invention performs deoxygenation and filtration on the cooling water by designing a water supply pipeline. The pressurized gas adopts a gas with stable chemical properties and not easily soluble in water, forming a closed test and research system, thereby greatly reducing pipeline corrosion and extending the service life of the system.

[0028] 5. The test and research system of the present invention designs the system pressure to be about 8.6 MPa by utilizing the fact that the physical properties of cooling water at about 8 MPa and 280°C are slightly different from those of cooling water at about 15.8 MPa and 293°C, thereby greatly reducing the design pressure of the test and research system and improving the safety attributes of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 A schematic diagram of an experimental research system according to an embodiment of the present invention is shown;

[0031] Figure 2 A schematic diagram of a method for flow control by a flow control system of the present invention is shown.

[0032] The above drawings include the following reference numerals:

[0033] 1. Gas compressor; 2. Buffer tank; 3. Spring safety valve; 4. Pressure regulating tank; 4a. Electric regulating valve; 4b. Pressure regulating tank connecting pipe; 5. Overflow tank; 5a. Electric regulating valve; 6. Upstream confluence pipeline; 7. Water supply pipeline; 7a. Water supply pump; 7b. Deaerator; 7c. Filter; 8. Water source tank; 9. Coolant in the tank; 10. Normal pressure water supply pipeline; 10a. Electric regulating valve; 11. High pressure water supply pipeline; 11a. Volume control pump; 11b. Fourth ultrasonic flowmeter; 11c. Electric regulating valve;

[0034] 12. First flow regulating pipeline; 13. Second flow regulating pipeline; 12a / 13a. Flow regulating valve; 12b. First ultrasonic flow meter; 13b. Second ultrasonic flow meter; 12c / 13c. Variable frequency pump; 12d / 12e / 12g / 12h / 13d / 13e / 13g / 13h. Electric regulating valve; 12f / 13f. Pipeline filter; 14. Plate heat exchanger;

[0035] 15. Main heating pipeline; 15a. Auxiliary heat regenerator; 15b. Regenerative heat exchanger; 15c. Heat storage tank; 15d. Main heater; 16. Auxiliary heat regenerator pipeline; 16a. Circulation pump; 16b. Auxiliary heat exchanger; 16c. Third ultrasonic flowmeter; 17. Air cooling tower; 17a. Cooling water outlet pipe of air cooling tower; 17b. Cooling water inlet pipe of air cooling tower. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] The present invention is further described in detail below in conjunction with specific embodiments, and these embodiments cannot be understood as limiting the scope of protection claimed by the present invention. The term "including" when used indicates the existence of a feature, but does not exclude the existence or addition of one or more other features; the orientation or position relationship indicated by the terms "lateral", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply 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; in addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0038] In the description, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0039] Example:

[0040] The present invention proposes a test research system suitable for pressurized water reactor regenerative heat exchanger, referring to Figure 1 As shown, the test circuit includes a water source control system, a pressure control system and a regenerative heat exchanger, and the water source control system and the pressure control system are both connected to the test circuit. The water source control system is used to fill the test circuit with water before the test and during the test, and the pressure control system increases the coolant pressure in the test circuit by filling gas.

[0041] The test loop includes a flow control system, a heating system and an auxiliary heat recovery system. The flow control system can control and adjust the flow in the test loop and input it into the heating system. The heating system includes a regenerative heat exchanger 15b. The heating system can heat the coolant in the test loop to a target temperature and then input it into the shell side of the regenerative heat exchanger 15b. The auxiliary heat recovery system provides cooling water of a specified temperature to the tube side of the regenerative heat exchanger 15b, and the cooling water is cooled by the cooling tower 17.

[0042] Specifically, the experimental research system includes an upstream conduit 6, part of which is connected between the upstream of the flow control system and the downstream of the heating system, constituting a part of the test loop, and the pressure control system and the water source control system are both connected to the upstream conduit 6.

[0043] Preferably, the pressure control system comprises a gas compressor 1, a buffer tank 2, a pressure stabilizing tank 4 and an overflow tank 5 connected in sequence, and the maximum charging pressure P of the gas compressor 1 is max Satisfy P max ≥8MPa, the regenerative heat exchanger test loop can be filled with chemically stable and water-insoluble gases, such as nitrogen, helium, argon, etc., to quickly increase the system pressure. The bottom of the surge tank 4 is connected to the upward confluence pipeline 6 through the surge tank connecting pipe 4b. In terms of pressure control, the chemically stable gas charging method is used to replace the electric heating rod to heat the cooling water to generate steam pressurization, so that the pressurization response speed is greatly improved, and the test research of the pressurized water reactor regenerative heat exchanger can be completed efficiently.

[0044] Further preferably, the overflow box 5 is respectively connected to the top, bottom and middle of the height direction of the pressure stabilizing tank 4. Specifically, the overflow box 5 is connected to the middle and lower part of the pressure stabilizing tank 4 through a pipeline, and an electric regulating valve 4a is arranged on the pipeline, and is connected to the pressure stabilizing tank connecting pipe 4b through a pipeline, and an electric regulating valve 5a is arranged on the pipeline.

[0045] In terms of volume parameters, the volume V1 of the bottom of the surge tank 4 through the buffer tank 2 and the volume V2 of the surge tank 4 satisfy: V1=V2, and the volume V3 of the overflow tank 5 and the coolant volume V0 in the experimental research system satisfy V3≥0.3V0.

[0046] In this way, after the coolant in the test research system increases in volume due to temperature rise, the coolant in the pressure stabilizing tank 4 can flow into the overflow tank 5 by opening the electric regulating valve 4a, and after the coolant decreases in volume due to temperature drop, the coolant in the overflow tank 5 can be replenished by opening the electric regulating valve 5a. The test research system of the present invention reduces the discharge of high-temperature cooling water during the test loop heating process by designing the overflow tank.

[0047] In the present invention, the flow control system includes a first flow regulating pipeline 12 and a second flow regulating pipeline 13 which are arranged in parallel and have different ranges. A flow regulating valve 12a or 13a, a flow meter and a variable frequency pump 12c or 13c are arranged on the first flow regulating pipeline 12 and the second flow regulating pipeline 13. The first flow regulating pipeline 12 is a large flow regulating pipeline, and the second flow regulating pipeline 13 is a small flow regulating pipeline.

[0048] Combination Figure 2As shown, the flow control system includes a flow controller, and the control formula of the flow controller is: Q1=k×f+c, where k and c are constants determined according to debugging tests, and f is the operating frequency of the variable frequency pumps 12c, 13c.

[0049] Specifically, the method for the flow control system to control the flow of the test loop is to first determine the value of f according to the control logic of the flow controller, and adjust the frequency of the variable frequency pumps 12c and 13c so that the relationship between the actual flow Q1 and the target flow Q is: Q1 = Q (1 + 2% ~ 5%), that is, Q1 is slightly greater than Q, and then fine-tune the flow control valves 12a and 13a to accurately control the target flow Q. If the target flow Q cannot be obtained, the operating frequency of the variable frequency pump on the corresponding loop can be slightly increased or decreased according to the difference between the flow feedback information received from the ultrasonic flowmeter and the target flow Q, and then the flow can be accurately controlled by adjusting the opening of the flow control valve until the target flow Q is obtained.

[0050] In other embodiments, if the accuracy requirement is not high, the variable frequency pumps 12c and 13c can be adjusted to directly make Q1≈Q. The above flow regulation method is applicable to the separate regulation of the first flow regulation pipeline 12 and the second flow regulation pipeline 13, and is also applicable to the joint regulation of the first flow regulation pipeline 12 and the second flow regulation pipeline 13.

[0051] Preferably, the upper range limit of the first ultrasonic flowmeter 12b on the first flow regulating pipeline 12 is 40t / h≤L1≤50t / h, and the upper range limit of the second ultrasonic flowmeter 13b on the second flow regulating pipeline 13 is 15t / h≤L2≤25t / h, and the range ratio is 10:1.

[0052] The experimental research system of the present invention achieves more precise control of the flow by designing the structure of the flow control system and the flow control method, adopting a model in which large-flow and small-flow pipelines work together and the flow controller cooperates with a variable frequency pump, an electric regulating valve, etc. for adjustment.

[0053] In addition, a plate heat exchanger 14 is connected between the first flow regulating pipeline 12 and the second flow regulating pipeline 13. The two shell sides of the plate heat exchanger 14 are respectively connected to the first flow regulating pipeline 12 and the second flow regulating pipeline 13 through pipelines with electric regulating valves, and the connection position is located downstream of the variable frequency pumps 12c and 13c. The pipe side of the plate heat exchanger 14 is connected to the cooling tower 17. The coolant temperature at the outlet of the cooling side of the plate heat exchanger is adjusted by controlling the opening of the electric regulating valves 12d, 12h, 12e, 13d, 13e and / or 13h on the corresponding pipelines to make the temperature lower than 98°C.

[0054] In the present application, the heating system includes a main heating pipeline 15, on which a regenerative heat exchanger 15b and an auxiliary heat regenerator 15a are provided, and the auxiliary heat regenerator 15a is located downstream of the regenerative heat exchanger 15b. The auxiliary heat regenerator 16 is an independent loop, and the auxiliary heat regenerator 16 of the auxiliary heat regenerator system includes the tube side of the regenerative heat exchanger 15b and the tube side of the auxiliary heat regenerator 15a. After the circulating cooling water in the auxiliary heat regenerator 16 flows through the tube side of the regenerative heat exchanger 15b and is heated, the high temperature is used to heat the coolant cooled on the shell side of the auxiliary heat regenerator 15a again, thereby realizing the utilization of heat recovery.

[0055] The auxiliary heat recovery pipeline 16 also includes a circulation pump 16a, a shell side of an auxiliary heat exchanger 16b and a third ultrasonic flowmeter 16c, and the tube side of the auxiliary heat exchanger 16b is connected to the cooling tower 17. The maximum flow rate of the circulation pump 16a is not less than 40 t / h; the cooling water outlet temperature of the auxiliary heat exchanger 16b tube side is lower than 98°C.

[0056] In the present invention, the cooling tower 17 is preferably an air cooling tower. By designing an auxiliary heat recovery pipeline and an auxiliary heat regenerator, heat energy is reused for a second time, thereby reducing heat loss during the test process.

[0057] Furthermore, the main heating pipeline 15 is also provided with a main heater 15d and a heat storage tank 15c. The heat storage tank 15c is located downstream of the main heater 15d, and the regenerative heat exchanger 15b is located downstream of the heat storage tank 15c. The water storage capacity of the heat storage tank 15c is not less than 6.6t, and the water storage temperature is not less than 280°C. The heat storage tank 15c includes a mixer and a temperature controller, which can distribute the coolant in the test loop and the water stored in the heat storage tank 15c appropriately to control the coolant temperature at the outlet of the heat storage tank 15c to reach the target temperature. By designing the heat storage tank and adopting a mode in which the heater and the preheater work in coordination, the preheating cycle and the number of heaters configured are greatly shortened.

[0058] In the present invention, the water source control system also includes a water supply pipeline 7 and a water source tank 8. The water supply pipeline 7 includes a water supply pump 7a, a deaerator 7b and a filter 7c. The end of the water supply pipeline 7 is connected to the water source tank 8. The water source tank 8 is located at the maximum elevation of the experimental research system and has an effective volume of not less than 8m 3 The water supplied by the water supply pump is stored in the water source tank 8 after being processed by the deaerator 7b and the filter 7c. The cooling water is deoxygenated and filtered by designing the water supply pipeline. The pressurized gas uses a gas with stable chemical properties and is not easily soluble in water, forming a closed test research system, thereby greatly reducing pipeline corrosion and extending the service life of the system.

[0059] The water source control system also includes a normal pressure water supply pipeline 10 and a high pressure water supply pipeline 11 arranged between the water source tank 8 and the test loop. The normal pressure water supply pipeline 10 is provided with an electric regulating valve 10a. The normal pressure water supply pipeline 10 uses the gravity of cooling water to fill the regenerative heat exchanger test loop with water through the upward confluence pipeline 6 by opening the electric regulating valve 10a. The high pressure water supply pipeline 11 includes a volume control pump 11a, an electric regulating valve 11c and a fourth ultrasonic flowmeter 11b, which are used for water replenishment during the test.

[0060] In addition, the pressure bearing capacity of each part of the test research system is designed to be no less than 8.6MPa, and the temperature resistance is no less than 300℃. By taking advantage of the fact that the physical properties of cooling water at 8MPa and about 280℃ are slightly different from those at 15.8MPa and about 293℃, the system pressure is designed to be about 8.6MPa instead of 15.8MPa, which greatly reduces the design pressure of the test research system and improves the safety attributes of the system.

[0061] In summary, the specific operation process of this embodiment is described below:

[0062] In the debugging preparation stage S1, the water supply pump 7a, deaerator 7b, and filter 7c are turned on in the water supply pipeline 7, so that the treated coolant 9 in the tank fills the water source tank 8. The electric regulating valve 10a is turned on in the normal pressure water supply pipeline 10 to use the gravity of the cooling water to fill the test loop of the regenerative heat exchanger through the upward converging pipeline 6. After the water filling is completed, the main heater 15d on the main heating pipeline 15 is turned on to increase the temperature and pressure of the coolant in the test loop to the target value, the reference value is 8MPa, 280℃.

[0063] Then start flow regulation, adjust the frequency conversion pump 12c of the first flow regulation pipeline 12 and the frequency conversion pump 13c of the second flow regulation pipeline 13 respectively, record the flow corresponding to the frequency conversion pump 12c or 13c at different frequencies, and the regulation mode includes the large flow pipeline working alone, the small flow pipeline working alone, and the large and small flow pipelines working together. According to the relationship Q1 = k × f + c, the values ​​of k and c in the formula are calculated by data fitting, and the data is input into the flow controller. When the flow controller adjusts the flow, according to the value of the target flow Q, the frequency f is adjusted to make the actual flow Q1 slightly higher than Q, and then the opening of the electric regulating valve 12a or 12h or 12g is adjusted to make the flow Q1 close to Q. Open the heat storage tank 15c so that the internal coolant reaches the target temperature, the reference value is 285 ° C. The test circuit does not need to be cooled and depressurized, and the preparation for debugging is completed.

[0064] During the test phase S2, the pressure, temperature and coolant dosage of the regenerative heat exchanger test loop are checked, and they can be supplemented to the target value through the gas compressor 1, the main heater 15d and the high-pressure water supply pipeline 11 respectively. The gas compressor can quickly pressurize the test loop pressure to a value slightly lower than the target value. If the target value is 8MPa, it can be pressurized to 5MPa first. Then, after the loop temperature rises, the pressure is adjusted accordingly. The test loop is heated mainly by the main heater 15d. With the cooperation of the heat storage tank 15c, the system loop can be quickly heated. During the heating process of the test system loop, due to the thermal expansion and contraction of the cooling water, part of the coolant enters the overflow tank 5. During the test, if there is a slight leak or loss of coolant in the test loop, it can be supplemented by the volume control pump 11a in the high-pressure water supply pipeline 11.

[0065] When adjusting the flow rate of the test loop, select a large flow pipeline or a small flow pipeline according to the target flow rate Q value to be adjusted. For example, when the range L1 of the first ultrasonic flowmeter 12b is 40t / h and the range L2 of the second ultrasonic flowmeter 13b is 15t / h, select a small flow pipeline when the target flow rate Q is lower than 15t / h, and select a large flow pipeline when the target flow rate Q is greater than 15t / h. The flow controller adjusts the frequency f of the variable frequency pump 12c or 13c according to the relationship between the values ​​of k and c determined in the debugging preparation stage S1, so that the measured flow rate Q1 is slightly higher than the target flow rate Q, and then the flow rate adjustment process is completed by adjusting the opening of the electric control valve 12a, 12h or 12g so that the flow rate Q1 is close to Q.

[0066] In addition, the auxiliary heat recovery pipeline 16 controls the cooling water temperature and flow rate at the tube side inlet of the regenerative heat exchanger 15b under the action of the circulation pump 16a, the auxiliary heat exchanger 16b, the third ultrasonic flowmeter 16c and the cooling tower 17. It should be noted that Figure 1 The schematic diagram of the regenerative heat exchanger 15b does not represent the actual layout of the pipelines, and the specific layout is mainly based on the test requirements. The cooling water heated on the tube side of the auxiliary regenerator 15a is used to heat the coolant cooled on its shell side to achieve the purpose of heat recovery.

[0067] At the end of the test, stage S3, there is no need to drain the coolant in the test loop. The plate heat exchanger 14 can be used to cool the test loop as required. The volume of cooling water is reduced and will be returned from the overflow tank 5 to the test loop, making it convenient for the next test.

[0068] In summary, from the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0069] 1. The experimental research system of the present invention adopts a gas pressurization method with stable chemical properties to replace the method of using electric heating rods to heat cooling water to generate steam pressurization in terms of pressure control, so that the pressurization response speed is greatly improved, and the experimental research of the pressurized water reactor regenerative heat exchanger can be completed efficiently.

[0070] 2. The experimental research system of the present invention realizes more precise control of the flow by designing the structure of the flow control system and the flow control method, adopting a model in which large-flow and small-flow pipelines work together and the flow controller cooperates with the frequency conversion pump, electric regulating valve, etc. for adjustment.

[0071] 3. The test research system of the present invention reduces the discharge of high-temperature cooling water during the heating process of the test loop by designing an overflow box; by designing a heat storage box and adopting a mode in which the heater and the preheater work together, the preheating cycle and the number of heaters configured are greatly shortened; by designing auxiliary heat recovery pipes and auxiliary heat recovery devices, the heat loss during the test is reduced, thereby greatly reducing the test cost, reducing energy waste, and having good economic benefits.

[0072] 4. The test and research system of the present invention performs deoxygenation and filtration on the cooling water by designing a water supply pipeline. The pressurized gas adopts a gas with stable chemical properties and not easily soluble in water, forming a closed test and research system, thereby greatly reducing pipeline corrosion and extending the service life of the system.

[0073] 5. The test and research system of the present invention designs the system pressure to be about 8.6 MPa by utilizing the fact that the physical properties of cooling water at about 8 MPa and 280°C are slightly different from those of cooling water at about 15.8 MPa and 293°C, thereby greatly reducing the design pressure of the test and research system and improving the safety attributes of the system.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An experimental research system suitable for pressurized water reactor regenerative heat exchangers, characterized in that: A test circuit comprising a water source control system, a pressure control system and a regenerative heat exchanger, wherein the water source control system and the pressure control system are both connected to the test circuit, the water source control system is used to fill the test circuit with water before the test and to fill the test circuit with water during the test, and the pressure control system increases the coolant pressure in the test circuit by filling gas; The test loop includes a flow control system, a heating system and an auxiliary heat recovery system. The flow control system can control and adjust the flow in the test loop and input it into the heating system. The heating system includes a regenerative heat exchanger (15b). The heating system can heat the coolant in the test loop to a target temperature and then input it into the shell side of the regenerative heat exchanger (15b). The auxiliary heat recovery system provides cooling water of a specified temperature to the tube side of the regenerative heat exchanger (15b), and the cooling water is cooled by the cooling tower (17).

2. The experimental research system according to claim 1, characterized in that: The flow control system comprises a first flow regulating pipeline (12) and a second flow regulating pipeline (13) which are arranged in parallel and have different measuring ranges, and the first flow regulating pipeline (12) and the second flow regulating pipeline (13) are both provided with flow regulating valves (12a, 13a), flow meters and variable frequency pumps (12c, 13c).

3. The experimental research system according to claim 2, characterized in that: The flow control system comprises a flow controller, and the control formula of the flow controller is: Q1=k×f+c, wherein k and c are constants determined according to a debugging test, and f is the operating frequency of the variable frequency pump (12c, 13c).

4. The experimental research system according to claim 3, characterized in that: The flow control system controls the flow of the test loop, firstly adjusts the frequency of the variable frequency pump (12c, 13c) according to the control logic of the flow controller, so that the relationship between the actual flow Q1 and the target flow Q is: Q1 = Q (1 + 2% ~ 5%), and then fine-tunes the flow regulating valve (12a, 13a) to obtain the target flow Q.

5. The experimental research system according to claim 2, characterized in that: The upper limit of the measuring range of the first ultrasonic flowmeter (12b) on the first flow regulating pipeline (12) is 40t / h≤L1≤50t / h, and the upper limit of the measuring range of the second ultrasonic flowmeter (13b) on the second flow regulating pipeline (13) is 15t / h≤L2≤25t / h, and the measuring range ratios are both 10:

1.

6. The experimental research system according to any one of claims 2 to 5, characterized in that: A plate heat exchanger (14) is connected between the first flow regulating pipeline (12) and the second flow regulating pipeline (13); the two shell sides of the plate heat exchanger (14) are respectively connected to the first flow regulating pipeline (12) and the second flow regulating pipeline (13) through pipelines with electric regulating valves; and the pipe side of the plate heat exchanger (14) is connected to the cooling tower (17).

7. The experimental research system according to claim 1, characterized in that: The heating system comprises a main heating pipeline (15), on which the regenerative heat exchanger (15b) and the auxiliary heat regenerator (15a) are provided, wherein the auxiliary heat regenerator (15a) is located downstream of the regenerative heat exchanger (15b), and an auxiliary heat regenerator pipeline (16) of the auxiliary heat regenerator system comprises a tube side of the regenerative heat exchanger (15b) and a tube side of the auxiliary heat regenerator (15a).

8. The experimental research system according to claim 7, characterized in that: The auxiliary heat recovery pipeline (16) is an independent loop, and also includes a circulation pump (16a), the shell side of the auxiliary heat exchanger (16b) and a third ultrasonic flow meter (16c); the tube side of the auxiliary heat exchanger (16b) is connected to the cooling tower (17).

9. The experimental research system according to claim 7, characterized in that: The main heating pipeline (15) is also provided with a main heater (15d) and a heat storage tank (15c). The heat storage tank (15c) is located downstream of the main heater (15d), and the regenerative heat exchanger (15b) is located downstream of the heat storage tank (15c). The heat storage tank (15c) includes a mixer and a temperature controller, which can distribute the coolant in the test loop and the stored water in the heat storage tank (15c), and control the coolant temperature at the outlet of the heat storage tank (15c) to reach the target temperature.

10. The experimental research system according to claim 1, characterized in that: The pressure control system comprises a gas compressor (1), a buffer tank (2), a pressure stabilizing tank (4) and an overflow tank (5) which are connected in sequence, and the overflow tank (5) is respectively connected to the top, bottom and middle of the pressure stabilizing tank (4) in the height direction.

11. The experimental research system according to claim 10, characterized in that: The volume V1 of the buffer tank (2) and the volume V2 of the pressure stabilizing tank (4) satisfy: V1 = V2, and the volume V3 of the overflow tank (5) and the volume V0 of the coolant in the experimental research system satisfy: V3≥0.3V0.

12. The experimental research system according to claim 1, characterized in that: The water source control system comprises a water supply pipeline (7) and a water source tank (8), wherein the water supply pipeline (7) comprises a water supply pump (7a), a deaerator (7b) and a filter (7c), and the end of the water supply pipeline (7) is connected to the water source tank (8), and the water source tank (8) is located at the maximum elevation of the experimental research system.

13. The experimental research system according to claim 12, characterized in that: The water source control system further comprises a normal-pressure water supply pipeline (10) and a high-pressure water replenishment pipeline (11) arranged between the water source tank (8) and the test loop, wherein the normal-pressure water supply pipeline (10) is used for filling water before the test, and the high-pressure water replenishment pipeline (11) comprises a volume control pump (11a) and a fourth ultrasonic flowmeter (11b) for replenishing water during the test.

14. The experimental research system according to any one of claims 10 to 13, characterized in that: The test research system comprises an upstream conduit (6), a portion of which is connected between the upstream of the flow control system and the downstream of the heating system, constituting a part of the test loop, and the pressure control system and the water source control system are both connected to the upstream conduit (6).

15. The experimental research system according to claim 1, characterized in that: The pressure bearing capacity of each part of the pipeline of the test research system shall not be less than 8.6MPa, and the temperature resistance shall not be less than 300℃.

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