Reactor core upper chamber equivalent scaling experiment table

Abstract

The invention relates to the technical field of reactor core upper chamber experiments, in particular to a reactor core upper chamber equivalent scaling experiment table which comprises an external loop and a pressure vessel. The pressure vessel comprises a pressure vessel shell and an internal structure assembly. The pressure vessel shell is provided with a lower water inlet and an upper water inlet which are respectively used for inputting cooling liquid with different temperatures; the internal structure assembly comprises a lower supporting plate, an end plug, a supporting column and a guide cylinder, wherein the size of the end plug, the size of the supporting column and the size of the guide cylinder perpendicular to the axial direction are reduced to be 0.25 times of the original size. The temperature monitoring device comprises a sheathed thermocouple and a temperature sensor and is used for monitoring temperature field distribution in the pressure vessel in real time, the equivalent scaling experiment table for the upper chamber of the reactor core can truly represent the states of a flow field and a temperature field in the upper chamber of the reactor core, and the temperature distribution condition of the upper chamber can be monitored, so that the equivalent scaling experiment table can be applied to the equivalent scaling experiment of the upper chamber of the reactor core. And the influence of the mixed flow phenomenon near the window of the control rod guide cylinder on the temperature distribution of the upper chamber can be monitored.

Description

Technical Field

[0001] The invention relates to the technical field of reactor core upper chamber experiments, in particular to an equivalent scaled-down experimental platform for a reactor core upper chamber. Background Art

[0002] At present, the existing core test benches are mainly divided into the following three types: (1) Overall performance test bench: The APEX (Advanced Plant Experiment) test bench prototype is the AP600 reactor. The ACME (Advanced Core-cooling Mechanism Experiment) test bench is used to study the performance of the CAP1400 passive core cooling system. The overall performance test bench includes all the chambers of the core. It is not only expensive and difficult to install, but also the temperature of the liquid flowing into the upper chamber cannot be flexibly adjusted; there is no temperature sensor installed in the upper chamber, and it is impossible to fully monitor the temperature field distribution of the upper chamber of the core in real time, nor can it analyze the temperature mixing phenomenon at the guide tube window. (2) Core heat exchange test bench: A bench for reactor core heat exchange testing (such as Chinese patent CN202411502412.5) only focuses on the temperature distribution near the fuel rod assembly in the lower chamber of the core, and simulates the heating of the fuel rod by heating rods. This type of test bench cannot analyze the temperature field of the upper chamber of the core. (3) Test bench for PWR control rod flow-induced vibration: A test bench for PWR control rod flow-induced vibration (e.g., Chinese patent CN201621465017.5) mainly consists of a control rod guide tube and a control rod assembly, with water flowing into the test section through an external circuit. This test bench is usually not equipped with components such as end plugs, support columns, and support plates, nor is it equipped with temperature sensors. It only flows normal temperature water for research and cannot analyze the temperature field.

[0003] Therefore, at present, no one in China has designed a test bench for the temperature field problem of the upper core chamber. In view of the above situation, there is an urgent need to develop an equivalent scaled-down test bench for the upper core chamber of the reactor to overcome the shortcomings in current practical applications. Summary of the Invention

[0004] The object of the present invention is to provide an equivalent scaled-down test bench for the upper chamber of a reactor core, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A reactor core upper chamber equivalent scale test bench comprises an external circuit and a pressure vessel; wherein the external circuit comprises a hydraulic drive device, a heating device, a cooling device and a temperature monitoring device; and the pressure vessel comprises a pressure vessel shell and internal structural components.

[0007] The pressure vessel shell is provided with a lower water inlet and an upper water inlet, respectively used for inputting coolant of different temperatures;

[0008] The internal structural components include a lower support plate, an end plug, a support column and a guide cylinder, wherein the dimensions of the end plug, the support column and the guide cylinder perpendicular to the axial direction are reduced to 0.25 times of the original dimensions;

[0009] The temperature monitoring device includes an armored thermocouple and a temperature sensor, which are used to monitor the temperature field distribution in the pressure vessel in real time.

[0010] As a further solution of the present invention: the heating device is a heating water tank, the outlet temperature of the heating water tank can be adjusted independently, and is symmetrically connected to the lower water inlet of the pressure vessel shell through two pipelines.

[0011] As a further solution of the present invention: the cooling device is a cooling pump, the outlet temperature of the cooling pump is set to a constant temperature, and the flow rate of the coolant flowing into the upper water inlet is regulated by a second speed regulating valve.

[0012] As a further solution of the present invention: the hydraulic drive device is a pipeline centrifugal pump, and its design power is calculated by the following formula:

[0013] P = Q × p;

[0014] Among them, Q is the design flow rate and p is the pipeline design pressure.

[0015] As a further solution of the present invention: the pressure vessel shell has eight lower water inlets, thirteen upper water inlets, three water outlets, and the water outlets are distributed at 120° to the center of the circle in the upper middle part of the container.

[0016] As a further solution of the present invention: the end plug is threadedly connected to the lower support plate through a claw structure, the support column is connected to the end plug through a thread, and the guide cylinder is connected to the lower support plate through a thread.

[0017] As a further solution of the present invention: the armored thermocouple is inserted through the inner hole of the support column until it extends out of the lower surface of the end plug.

[0018] As a further solution of the present invention: the pressure vessel shell is provided with an upper viewing window and a lower viewing window for observing the status of internal components and the position of the end plug respectively;

[0019] The top of the pressure vessel shell is also provided with a thermocouple mounting hole for inserting the armored thermocouple.

[0020] As a further solution of the present invention: the external circuit also includes a safety valve and a filter, and the safety valve and the filter are arranged in parallel to prevent the system from being blocked and overpressured.

[0021] As a further solution of the present invention: the internal structural assembly also includes an upper support plate for achieving radial positioning of the guide cylinder and the support column.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The test bench of the present invention is equipped with scaled-down end plugs, support columns, guide cylinders, upper and lower support plates, and other components, enabling realistic reproduction of the flow and temperature fields within the upper chamber of the reactor core. Multiple temperature sensors are installed within the pressure vessel to monitor the temperature distribution within the upper chamber and the impact of mixed flow near the control rod guide cylinder windows on the temperature distribution within the upper chamber. The temperatures of the upper and lower water inlets of the pressure vessel can be flexibly adjusted, and the loading boundary conditions are more easily controlled compared to those of a test bench for overall reactor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the external circuit in an embodiment of the present invention.

[0025] Figure 2 This is a side view of the pressure vessel in an embodiment of the present invention with half of the pressure vessel shell removed.

[0026] Figure 3 It is a cross-sectional view of a circular cross section of a pressure vessel in an embodiment of the present invention.

[0027] Figure 4 2 is a top view of a pressure vessel in an embodiment of the present invention.

[0028] Figure 5 2 is a bottom view of the pressure vessel in an embodiment of the present invention.

[0029] In the figure: 1- pipeline centrifugal pump, 2- filter, 3- safety valve 1, 4- pressure sensor 1, 5- safety valve 2, 6- water storage tank, 7- speed regulating valve 1, 8- cooling pump, 9- flow sensor, 10- detection assembly 1, 11- speed regulating valve 2, 12- detection assembly 2, 13- pressure vessel, 14- detection assembly 3, 15- heating water tank, 16- speed regulating valve 3, 17- pressure sensor 2, 18- upper window, 19- end plug, 20- support column, 21- guide cylinder, 22- temperature sensor, 23- pressure vessel shell, 24- upper water inlet, 25- lower water inlet, 26- upper support plate, 27- lower window, 28- lower support plate, 29- armored thermocouple, 30- water outlet, 31- thermocouple mounting hole. DETAILED DESCRIPTION

[0030] The following will provide a clear and complete description of 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 them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0032] See also Figure 1-Figure 5 An embodiment of the present invention provides a reactor core upper chamber equivalent scale test bench, comprising an external circuit and a pressure vessel 13; wherein the external circuit comprises a hydraulic drive device, a heating device, a cooling device, and a temperature monitoring device; and the pressure vessel 13 comprises a pressure vessel shell 23 and internal structural components.

[0033] The pressure vessel shell 23 is provided with a lower water inlet 25 and an upper water inlet 24, which are used to input coolant of different temperatures respectively;

[0034] The internal structural components include a lower support plate 28, an end plug 19, a support column 20 and a guide cylinder 21, wherein the dimensions of the end plug 19, the support column 20 and the guide cylinder 21 perpendicular to the axial direction are reduced to 0.25 times of the original dimensions;

[0035] The temperature monitoring device includes an armored thermocouple 29 and a temperature sensor 22 , and is used to monitor the temperature field distribution in the pressure vessel 13 in real time.

[0036] The heating device is a heating water tank 15 , the outlet temperature of the heating water tank 15 can be independently adjusted, and the heating water tank 15 is symmetrically connected to the lower water inlet 25 of the pressure vessel shell 23 through two pipelines.

[0037] The cooling device is a cooling pump 8 , the outlet temperature of the cooling pump 8 is set to a constant temperature, and the flow rate of the coolant flowing into the upper water inlet 24 is adjusted by the second speed regulating valve 11 .

[0038] The hydraulic drive device is a pipeline centrifugal pump 1, and its design power is calculated by the following formula:

[0039] P = Q × p;

[0040] Among them, Q is the design flow rate and p is the pipeline design pressure.

[0041] The pressure vessel shell 23 has eight lower water inlets 25 , thirteen upper water inlets 24 , and three water outlets 30 , which are distributed at 120° to the center of the circle in the upper middle portion of the container.

[0042] The end plug 19 is threadedly connected to the lower support plate 28 through a claw structure, the support column 20 is threadedly connected to the end plug 19, and the guide cylinder 21 is threadedly connected to the lower support plate 28.

[0043] The armored thermocouple 29 is inserted through the inner hole of the support column 20 until it extends out of the lower surface of the end plug 19.

[0044] The pressure vessel shell 23 is provided with an upper viewing window 18 and a lower viewing window 27 for observing the status of internal components and the position of the end plug 19 respectively;

[0045] The top of the pressure vessel shell 23 is also provided with a thermocouple mounting hole 31 for inserting the armored thermocouple 29 .

[0046] The external circuit also includes a safety valve 3 and a filter 2. The safety valve 3 and the filter 2 are arranged in parallel to prevent the system from being blocked and over-pressurized.

[0047] The internal structural assembly further includes an upper support plate 26 for achieving radial positioning of the guide cylinder 21 and the support column 20 .

[0048] The reactor core upper chamber equivalent scale test bench is designed to study the temperature distribution within the upper chamber and the impact of mixed flow near the control rod guide tube window on the temperature distribution within the upper chamber. It can simulate the temperature and flow fields within the reactor upper chamber, the temperature loading conditions of multiple core outlet channels, and the impact of the guide tube lower window on internal components. Multiple temperature sensors are installed within the test bench to monitor the internal temperature of the pressure vessel in real time.

[0049] Example 1: External circuit and pressure vessel 13;

[0050] 1. External circuit:

[0051] The external circuit includes a hydraulic drive device, a heating device, a cooling device, a measuring device, a water storage device, a safety protection device, an auxiliary device and a speed regulating device.

[0052] The hydraulic drive device is a pipeline centrifugal pump 1; the heating device is a heating water tank 15, used to heat the circulating water; the cooling device is a cooling pump 8, used to cool the circulating water; the measuring devices are flow sensor 9, pressure sensor 1 4, pressure sensor 2 17, and detection assembly 1 10, detection assembly 2 12, and detection assembly 3 14, which are assembled from flow sensors, temperature sensors, and pressure sensors. These are installed at multiple locations on the pipeline to monitor the operating status of the experimental device. The water storage device is a water storage tank 6, which has an inlet and an outlet for storing water and provides space for mixing water with uneven temperatures. The safety protection devices are safety valve 1 3 and safety valve 2 5, both of which are spring-loaded safety valves. They open when the inlet and outlet pressure differential exceeds a set value, protecting the hydraulic system. The auxiliary device is filter 2, used to filter impurities in the hydraulic system. The speed control devices are speed control valve 1 7, speed control valve 2 11, and speed control valve 3 16, used to adjust the flow rate of each branch of the external circuit.

[0053] 2. Pressure vessel 13:

[0054] The pressure vessel 13 includes a pressure vessel shell 23, internal structural components, a temperature measuring device, and a temperature monitoring device.

[0055] The pressure vessel shell 23 has an upper viewing window 18 and a lower viewing window 27, eight lower water inlets 25 at the bottom, thirteen upper water inlets 24 at the top, and three water outlets 30 distributed at an angle of 120° to the center of the circle in the upper middle portion of the vessel.

[0056] The internal structural components include an upper support plate 26, a lower support plate 28, an end plug 19, a support column 20 and a guide cylinder 21;

[0057] The temperature measuring device is an armored thermocouple 29, which is installed at the core outlet for temperature measurement;

[0058] The temperature monitoring device is a temperature sensor 22 , which is installed in the pressure vessel shell 23 and is used to monitor the temperature of multiple locations in the pressure vessel 13 .

[0059] Example 2: The heating device is a heating water tank 15, and the outlet of the heating water tank 15 can be set to a constant temperature. Each heating water tank 15 is set to a different temperature and is divided into two pipelines to flow into the pressure vessel shell 23. The temperature of the lower water inlet 25 of the pressure vessel shell 23 at a symmetrical position about the center of the circle is the same.

[0060] The cooling device is a cooling pump 8. The outlet temperature of cooling pump 8 can be set to a constant temperature. A portion of the low-temperature water flowing out of cooling pump 8 flows directly into thirteen upper water inlets 24 in the upper portion of pressure vessel shell 23, while the remaining portion flows back into water storage tank 6 to continue circulation. The flow rate of coolant flowing into upper water inlets 24 of pressure vessel shell 23 can be adjusted by regulating valve 11.

[0061] Safety valve 1 3 is connected in parallel with filter 2 to prevent safety risks caused by blockage of filter 2. Safety valve 2 5 is connected in parallel with the entire experimental device circuit to prevent safety risks caused by blockage problems inside the system.

[0062] Regulator valve 3 (16), connected in series with the pressure vessel, regulates the flow of water entering the heated water tank 15, ensuring that the flow rate of water entering the four heated water tanks 15 from the four parallel pipelines is the same. Regulator valve 1 (7), connected in parallel with cooling pump 8, regulates the flow of water cooled by cooling pump 8. Regulator valve 2 (11), connected from the outlet of cooling pump 8 to the upper portion of the pressure vessel shell 23, regulates the flow of water from the water inlet 24 at the upper portion of the pressure vessel shell 23.

[0063] Multiple temperature sensors in the pipeline measure the temperatures at the lower water inlet 25, upper water inlet 24, and three water outlets 30 of the pressure vessel shell 23. Multiple pressure sensors measure the pressures at the lower water inlet 25, upper water inlet 24, three water outlets 30 of the pressure vessel shell, the outlet of the pipeline centrifugal pump 1, and the inlet of the filter 2. Multiple flow sensors measure the flow rates at the lower water inlet 25, upper water inlet 24, three water outlets 30 of the pressure vessel shell 23, as well as the flow rate into the cooling pump 8.

[0064] Example 3: The end plug 19 is threadedly connected to the lower support plate 28 through its own claw structure. The end plug 19 is also threadedly connected to the support column 20, and the guide cylinder 21 is also threadedly connected to the lower support plate 28. The upper support plate 26 is used to position the guide cylinder 21 and the support column 20 perpendicular to the axial direction.

[0065] The upper viewing window 18 and lower viewing window 27 of the pressure vessel shell 23 are used to observe the internal components of the pressure vessel 13, the installation of the temperature sensor 22 inside the pressure vessel shell 23, and the position of the guide tube 21 and support column 20. The eight lower water inlets 25 in the lower portion of the pressure vessel shell 23 are used to supply coolant of varying temperatures to the core. The thirteen upper water inlets 24 deliver low-temperature coolant into the pressure vessel shell 23. All coolant flows out through the three water outlets 30 in the pressure vessel shell 23. The eight upper thermocouple mounting holes 31 are used to insert armored thermal couplers 29. Two truncated cones are located inside the pressure vessel shell 23 to position the upper and lower support plates 26 and 28.

[0066] The inner diameter of the end plug 19 remains unchanged, and the other radial dimensions are reduced by 0.25 times. The dimensions of the guide cylinder 21 and the support column 20 perpendicular to the axial direction are reduced by 0.25 times.

[0067] Therefore, the present invention designs an equivalent scaled-down test bench for the upper chamber of the reactor core to study the temperature field distribution in the upper chamber of the core and analyze the influence of the mixed flow phenomenon near the control rod guide tube window on the temperature distribution in the upper chamber, which has important engineering significance and value.

[0068] In summary, the reactor core upper chamber equivalent scale test bench of the present invention includes an external loop and a pressure vessel 13 .

[0069] The driving device is a pipeline centrifugal pump 1. The design power of the pipeline centrifugal pump 1 is calculated by the following formula:

[0070] P = Q × p;

[0071] Where Q is the design flow rate and p is the pipeline design pressure.

[0072] The design pressure of the system is calculated using the following formula:

[0073] P = kρgh;

[0074] Wherein, k is the margin coefficient, ρ is the density of water, g is the acceleration due to gravity, and h is the height of the pressure vessel 13 .

[0075] The design flow rate is calculated using the following formula:

[0076] Q2=1.02×S×v;

[0077] Wherein, S is the cross-sectional area of the portion of the pressure vessel 13 through which water can flow, and v is the designed flow rate of water in the pressure vessel 13 .

[0078] The heating device is a heating water tank 15, and the water tank can be set to a target temperature to ensure that the temperature of the output high-temperature water is constant.

[0079] The water temperature output from the four heated water tanks 15 can be adjusted to simulate high-temperature water in different core channels. Each heated water tank 15 is divided into two pipelines, connected to the lower water inlet 25 of the pressure vessel shell 23. The corresponding water inlets of the two pipelines are symmetrical about the center of a cross-section of the pressure vessel shell 23 perpendicular to the axis.

[0080] The cooling device is a cooling pump 8, and the cooling pump 8 outlets can be set to a constant temperature to ensure that the low-temperature water temperature of the output is constant. The water temperature of the water inlet at the upper part of the pressure vessel 13 can be changed by adjusting the temperature setting value.

[0081] The water storage device is a water tank 6.

[0082] The safety protection devices are safety valve 1 3 and safety valve 2 5, both of which are spring-loaded safety valves. When the pressure difference between the front and rear of the valve exceeds the set value, the spring-loaded pressure valve opens.

[0083] The auxiliary device is a filter 2.

[0084] In the external circuit, the pipes connecting each device are connected by hard pipes and welding.

[0085] The pressure vessel shell 23 includes an upper viewing window 18 and a lower viewing window 27. The upper viewing window 18 is used to observe the status of the guide cylinder 21, support column 20, and temperature sensor 22, while the lower viewing window 27 is used to observe the position of the end plug 19 and lower support plate 28. The inner diameter of the pressure vessel shell 23 has two truncated cones for securing the upper support plate 26 and lower support plate 28. The lower portion of the pressure vessel shell 23 has eight lower water inlets 25, the upper portion has thirteen upper water inlets 24 and eight thermocouple mounting holes 31, and the upper portion has three water outlets 30, each with an angle of 120° to the axial direction.

[0086] The internal structural components include an upper support plate 26 , a lower support plate 28 , an end plug 19 , a support column 20 and a guide cylinder 21 .

[0087] Among them, the upper support plate 26 and the lower support plate 28 are axially positioned with the pressure vessel shell 23 by the truncated cone inside the pressure vessel shell 23 and their own gravity, and radial positioning is achieved by the outer diameter of the upper support plate 26 and the lower support plate 28 contacting the inner diameter of the pressure vessel shell 23.

[0088] The end plug 19 is threadedly connected to the support column 20. This is in turn threadedly connected to the lower support plate 28 via a claw mechanism. The guide cylinder 21 is also threadedly connected to the lower support plate 28. The support column 20 and guide cylinder 21 achieve radial positioning by contacting their outer diameters with the inner diameters of the holes in the upper support plate 26. The inner diameter of the end plug 19 remains unchanged, while other radial dimensions are reduced by 0.25 times. The dimensions perpendicular to the axial direction of the guide cylinder 21 and support column 20 are also reduced by 0.25 times.

[0089] The temperature measuring device is an armored thermocouple 29 , which is inserted through the inner hole of the support column 20 until it extends out of the lower surface of the end plug 19 .

[0090] The temperature monitoring device is a temperature sensor 22, which is mounted on the internal structural component through a ferrule.

[0091] The operating principle of the reactor core upper chamber equivalent scale test bench of the present invention is as follows: Turn on the pipeline centrifugal pump 1, adjust the speed control valve 3 16, and ensure that the flow sensor readings of the four parallel branches in the detection assembly 3 14, which is an installation assembly of flow sensors, temperature sensors, and pressure sensors, are consistent. The temperature setpoint of the heating water tank 15 is adjusted to ensure that the water temperatures in different channels of the lower water inlet 25 of the heating water tank 15 are different. The speed control valve 1 7 is adjusted to ensure that the flow rate of water entering the cooling pump 8 meets the system requirements of the cooling pump 8. The flow rate of water entering the cooling pump 8 is measured by the flow sensor 9.

[0092] The armored thermocouple 29 is inserted into the pressure vessel 13 through the thermocouple mounting hole 31 of the pressure vessel shell 23 and gradually inserted until the armored thermocouple 29 protrudes from the lower surface of the end plug 19. By analyzing the temperature measurement results of the temperature sensor 22, the distribution of the temperature field in the pressure vessel 13 is analyzed.

[0093] If a blockage occurs inside the experimental device, the reading on pressure sensor 17 rises. When the pressure reaches the opening pressure of safety valve 5, safety valve 5 opens, protecting the circuit. If the filter is clogged, the reading on pressure sensor 4 rises. When the pressure reaches the opening pressure of safety valve 3, safety valve 3 opens, protecting the experimental system.

[0094] Therefore, in the pressure vessel 13, a temperature sensor 22 is fixedly installed on the inner wall of the pressure vessel shell 23, a lower support plate 28 and an upper support plate 26 are fixedly installed inside the pressure vessel shell 23, a temperature sensor 22, an end plug 19 and a guide cylinder 21 are fixedly installed on the lower support plate 28, a support column 20 is fixedly installed on the end plug 19, a temperature sensor 22 is fixedly installed on the guide cylinder 21, and a support column 20 and a guide cylinder 21 are slidably installed in the inner hole of the upper support plate 26.

[0095] In the external circuit, various components are connected via metal pipes. Pressure sensor 2 17, speed control valve 3 16, heating water tank 15, detection assembly 3 14, and the lower water inlet 25 of the pressure vessel shell 23 are fixedly installed behind the centrifugal pump 1. Detection assembly 10 is fixedly installed behind the three water outlets 30 of the pressure vessel shell 23. Flow sensor 9 is connected in series with cooling pump 8 and then in parallel with speed control valve 1 7. One branch of the cooling pump 8 outlet is fixedly installed with speed control valve 2 11, detection assembly 2 12, and the upper water inlet 24 of the pressure vessel shell 23. Another branch of the cooling pump 8 outlet is fixedly installed with a water storage tank 6, pressure sensor 1 4, a parallel filter 2, and safety valve 1 3. Safety valve 2 5 is fixedly installed behind pressure sensor 2 17.

[0096] It should be noted that, in the present invention, unless otherwise expressly specified or limited, the terms "sliding," "rotating," "fixed," and "provided with," etc., should be understood in a broad sense. For example, they may refer to welded connections, bolted connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise expressly specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0097] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A reactor core upper chamber equivalent scale test bench, characterized in that: The invention comprises an external circuit and a pressure vessel (13); wherein the external circuit comprises a hydraulic drive device, a heating device, a cooling device and a temperature monitoring device; and the pressure vessel (13) comprises a pressure vessel shell (23) and an internal structural component. The pressure vessel shell (23) is provided with a lower water inlet (25) and an upper water inlet (24), which are respectively used to input cooling liquids of different temperatures; The internal structural assembly comprises a lower support plate (28), an end plug (19), a support column (20) and a guide cylinder (21), wherein the dimensions of the end plug (19), the support column (20) and the guide cylinder (21) perpendicular to the axial direction are reduced to 0.25 times of the original dimensions; The temperature monitoring device comprises an armored thermocouple (29) and a temperature sensor (22), and is used for real-time monitoring of the temperature field distribution in the pressure vessel (13).

2. The reactor core upper chamber equivalent scale test bench according to claim 1, characterized in that: The heating device is a heating water tank (15), the outlet temperature of the heating water tank (15) can be independently adjusted, and is symmetrically connected to the lower water inlet (25) of the pressure vessel shell (23) through two pipelines.

3. The reactor core upper chamber equivalent scale test bench according to claim 1, characterized in that: The cooling device is a cooling pump (8), the outlet temperature of the cooling pump (8) is set to a constant temperature, and the flow rate of the cooling liquid flowing into the upper water inlet (24) is regulated by the second speed regulating valve (11).

4. The reactor core upper chamber equivalent scale test bench according to claim 1, characterized in that: The hydraulic drive device is a pipeline centrifugal pump (1), and its design power is calculated by the following formula: P = Q × p; Among them, Q is the design flow rate and p is the pipeline design pressure.

5. The reactor core upper chamber equivalent scale test bench according to any one of claims 1 to 4, characterized in that: The pressure vessel shell (23) has eight lower water inlets (25), thirteen upper water inlets (24), and three water outlets (30), and the water outlets (30) are distributed at 120 degrees to the center of the circle in the upper middle portion of the container.

6. The reactor core upper chamber equivalent scale test bench according to claim 1, characterized in that: The end plug (19) is threadedly connected to the lower support plate (28) through a claw structure, the support column (20) is threadedly connected to the end plug (19), and the guide cylinder (21) is threadedly connected to the lower support plate (28).

7. The reactor core upper chamber equivalent scale test bench according to claim 1, characterized in that: The armored thermocouple (29) is inserted through the inner hole of the support column (20) until it extends out of the lower surface of the end plug (19).

8. The reactor core upper chamber equivalent scale test bench according to claim 7, characterized in that: The pressure vessel shell (23) is provided with an upper viewing window (18) and a lower viewing window (27), which are used to observe the status of internal components and the position of the end plug (19) respectively; The top of the pressure vessel shell (23) is also provided with a thermocouple mounting hole (31) for inserting the armored thermocouple (29).

9. The reactor core upper chamber equivalent scale test bench according to claim 1 or 8, characterized in that: The external circuit also includes a safety valve (3) and a filter (2). The safety valve (3) and the filter (2) are arranged in parallel to prevent the system from being blocked and over-pressurized.

10. The reactor core upper chamber equivalent scale test bench according to claim 9, characterized in that: The internal structural assembly further comprises an upper support plate (26) for achieving radial positioning of the guide cylinder (21) and the support column (20).

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