A steam generator feedwater assembly thermal stratification test system and test method

Abstract

The embodiment of the present application provides a kind of steam generator water supply component thermal stratification test system and test method, comprising: steam generator container simulation device, heat source heat exchanger, main circulating pump, water supply circulating pump and water supply heat exchanger;The water inlet pipe of the steam generator container simulation device, heat source heat exchanger, main circulating pump, the water outlet pipe of the steam generator container simulation device are sequentially connected into saturated water circulation loop by pipeline;The water supply component of the steam generator container simulation device, water supply heat exchanger, water supply circulating pump and the water outlet pipe of the steam generator container simulation device are connected into water supply circulation loop by pipeline.The embodiment of the present application realizes the real simulation of low-power steady-state condition and power transient condition steam generator water supply component prototype thermal hydraulic characteristics.

Description

Technical Field

[0001] This invention relates to a test system and method for thermal stratification of a steam generator feedwater assembly. Background Technology

[0002] During the process of starting up and transitioning to low-power operation of a pressurized water reactor (PWR), residual feedwater remains in the inlet pipe section, elbows, and feedwater ring of the steam generator feedwater assembly. The temperature of this residual feedwater approaches the saturation temperature of the secondary side of the steam generator. After the steam generator is put into operation, the lower-temperature, lower-flow-rate feedwater flows into the feedwater ring through the elbows in the inlet pipe section.

[0003] Due to insufficient mixing of the cold and hot fluids, the high-temperature, low-density residual feedwater occupies the upper part of the feedwater ring pipe, while the low-temperature, high-density residual feedwater occupies the lower part, resulting in fluid thermal stratification within the feedwater ring pipe. Furthermore, the significant temperature difference between the fluids inside and outside the feedwater assembly pipe generates additional overall bending thermal stress in the feedwater ring pipe cross-section. When thermal stratification occurs, thermal ripple oscillations are generated at the interface between the cold and hot fluids. These oscillations act on the inner wall of the pipe, causing localized thermal stress.

[0004] The superposition of these two stresses can lead to hazards such as pipe cracking, displacement, thermal fatigue, bending, and excessive load on supporting components, shortening the service life of the feedwater assembly. Furthermore, as a component of the secondary pressure-bearing boundary of the steam generator, thermal stratification of the feedwater assembly poses a potential threat to the structural integrity and operational safety of the steam generator. Therefore, thermal stratification tests must be conducted on the feedwater assembly of pressurized water reactor steam generators to develop targeted measures during research and development, design, and operation. Summary of the Invention

[0005] This invention provides a thermal stratification test system and method for a steam generator feedwater assembly, to achieve realistic simulation of the prototype thermal-hydraulic characteristics of the steam generator feedwater assembly under low-power steady-state and high-power transient conditions.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] In a first aspect, embodiments of the present invention provide a thermal stratification test system for a steam generator feedwater assembly, comprising: a steam generator container simulation device, a heat source heat exchanger, a main circulation pump, a feedwater circulation pump, and a feedwater heat exchanger; the inlet pipe of the steam generator container simulation device, the heat source heat exchanger, the main circulation pump, and the outlet pipe of the steam generator container simulation device are sequentially connected by pipes to form a saturated water circulation loop.

[0008] The water supply components, water supply heat exchanger, water supply circulation pump, and water outlet pipe of the steam generator container simulation device are connected by pipelines to form a water supply circulation loop.

[0009] Furthermore, the saturated water circulation loop is also connected to a demineralized water supply system and a pressure stabilizing system; the demineralized water supply system is connected to the saturated water circulation loop through a first valve.

[0010] Furthermore, the demineralized water supply system is connected to the heat source heat exchanger via a first valve and a first flow meter.

[0011] Furthermore, the main circulation pump is connected to the first flow meter via a second valve.

[0012] Furthermore, the voltage stabilizing system includes:

[0013] The pressure regulator is connected to the inlet pipe of the steam generator vessel simulation device via an electric regulating valve and a shut-off valve.

[0014] Furthermore, the feedwater heat exchanger is connected to the feedwater assembly of the steam generator container simulation device via a second flow meter and a third valve.

[0015] Furthermore, the first valve is a shut-off valve; the second valve is a check valve; and the third valve is an electrically controlled regulating valve.

[0016] Furthermore, the heat source heat exchanger is equipped with an electric regulating valve for the steam pipeline.

[0017] Secondly, embodiments of the present invention provide a test method based on the thermal stratification test system for the steam generator feedwater assembly, comprising:

[0018] The flow and temperature of the saturated water circulation loop and the feedwater circulation loop are linked to achieve the simulation of the steady-state temperature field of the feedwater assembly prototype in the steam generator vessel simulation device under low-power steady-state conditions, as well as the simulation of the transient temperature field of the feedwater assembly prototype under the conditions from start-up to low-power operation.

[0019] Furthermore, the flow rate and temperature of the saturated water circulation loop and the feed water circulation loop are adjusted in a coordinated manner, including:

[0020] Inject demineralized water into the saturated water circulation loop and establish the water level of the pressure stabilization system. Turn on the power supply of the pressure stabilization system to heat and pressurize to the test pressure.

[0021] Add demineralized water to the saturated water circulation loop until the saturated water circulation loop reaches the test pressure, then shut down the demineralized water supply system.

[0022] Turn on the main circulation pump and adjust the flow rate in the saturated water circulation loop to the test flow rate;

[0023] Steam is introduced into the heat source heat exchanger to heat the saturated water circulation loop to the test temperature;

[0024] Turn on the feedwater circulation pump and adjust the feedwater circulation loop flow rate to the rated feedwater flow rate so that the feedwater heat exchanger cools the feedwater to the rated temperature.

[0025] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0026] This invention discloses a thermal stratification test system and method for a steam generator feedwater assembly. Through a steam generator vessel simulation device, a saturated water circulation loop, and a feedwater circulation loop, it achieves a realistic simulation of the prototype thermal-hydraulic characteristics of the steam generator feedwater assembly under low-power steady-state conditions and high-power transient conditions with a relatively small heat source and water volume. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the thermal stratification test system for the steam generator feedwater assembly.

[0029] Figure 2 This is a schematic diagram of the structure of a steam generator container simulation device.

[0030] Figure 3 This is a schematic diagram of the water inlet distributor.

[0031] Figure 4 This is a schematic diagram of the bottom structure of the water inlet distributor.

[0032] Figure 5 for Figure 4 A partially enlarged structural diagram of A.

[0033] Figure 6 This is a top view of the temperature sensing component.

[0034] Figure 7 This is a side view of the temperature sensing component.

[0035] The attached diagram shows the markings and corresponding component names:

[0036] 1-Water supply assembly; 2-Temperature measuring assembly; 3-Manhole; 4-Water inlet pipe; 5-Upper straight section; 6-Inclined conical section; 7-Inner cylinder movable section; 8-Inner cylinder positioning device; 9-Lower straight section; 10-Inner cylinder fixed section; 11-Inner cylinder support ring plate; 12-Skirt; 13-Water outlet pipeline; 14-Water outlet pipe; 15-Inner cylinder hanger; 16-Water inlet distributor; 17-Inner cylinder lifting ring;

[0037] 101-Steam generator vessel simulation device; 102-Pressure stabilizer; 103-Electric regulating valve; 104-Stop valve; 105-Heat source heat exchanger; 106-Electric regulating valve for steam pipeline; 107-Demineralized water supply system; 108-First flow meter; 109-First valve; 110-Second valve; 111-Main circulation pump; 112-Feed water circulation pump; 113-Feed water heat exchanger; 114-Second flow meter; 115-Third valve. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0039] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0040] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0042] Example 1

[0043] To address the technical problem that thermal stratification of fluids may compromise the structural integrity of the feedwater assembly in a pressurized water reactor's steam generator, leading to safety risks, in a first aspect, embodiments of the present invention provide a thermal stratification test system for a steam generator feedwater assembly, referring to... Figure 1-7 As shown, it includes: a steam generator container simulation device 101, a heat source heat exchanger 105, a main circulation pump 111, a feed water circulation pump 112, and a feed water heat exchanger 113; the inlet pipe of the steam generator container simulation device, the heat source heat exchanger, the main circulation pump, and the outlet pipe of the steam generator container simulation device are connected in sequence through pipelines to form a saturated water circulation loop.

[0044] The water supply components, water supply heat exchanger, water supply circulation pump, and water outlet pipe of the steam generator container simulation device are connected by pipelines to form a water supply circulation loop.

[0045] By coordinating the flow and temperature of the saturated water circulation loop and the feedwater circulation loop, the steady-state temperature field of the feedwater assembly prototype under low-power steady-state conditions can be simulated; as well as the transient temperature field of the feedwater assembly prototype under the conditions from reactor start-up to low-power operation.

[0046] In this embodiment of the invention, heat is carried in by a saturated water circulation loop, and saturated water is used instead of saturated steam-water mixture as working fluid to eliminate latent heat of vaporization and significantly reduce the cost of heat source; the injection at the top of the container realizes the simulation of hydrophobicity on the secondary side of the steam generator, eliminating the steam-water separation device and simplifying the structure; heat is carried out from the bottom of the container through the feed water circulation loop and cooled to the feed water temperature to realize a closed loop, which greatly reduces the amount of water.

[0047] Thus, the embodiments of the present invention, through a steam generator vessel simulation device, a saturated water circulation loop, and a feedwater circulation loop, achieve a realistic simulation of the prototype thermal-hydraulic characteristics of the steam generator feedwater assembly under low-power steady-state conditions and high-power transient conditions, with a relatively small heat source and water volume.

[0048] Furthermore, the saturated water circulation loop is also connected to a demineralized water supply system 107 and a pressure stabilizing system; the demineralized water supply system is connected to the saturated water circulation loop through a first valve.

[0049] Furthermore, the demineralized water supply system is connected to the heat source heat exchanger via the first valve 109 and the first flow meter 108.

[0050] Furthermore, the main circulation pump is connected to the first flow meter via the second valve 110.

[0051] Furthermore, the voltage stabilizing system includes:

[0052] The pressure regulator 102 is connected to the water inlet pipe of the steam generator container simulation device via the electric regulating valve 103 and the shut-off valve 104.

[0053] Furthermore, the water supply heat exchanger 113 is connected to the water supply assembly of the steam generator container simulation device via the second flow meter 114 and the third valve 115 in sequence.

[0054] Furthermore, the first valve is a shut-off valve; the second valve is a check valve; and the third valve is an electrically controlled regulating valve.

[0055] Furthermore, the heat source heat exchanger is equipped with an electric regulating valve 106 for the steam pipeline.

[0056] Secondly, embodiments of the present invention provide a test method based on the thermal stratification test system for the steam generator feedwater assembly, comprising:

[0057] S1. The flow and temperature of the saturated water circulation loop and the feedwater circulation loop are linked to achieve the simulation of the steady-state temperature field of the feedwater assembly prototype in the steam generator vessel simulation device under low-power steady-state conditions, as well as the simulation of the transient temperature field of the feedwater assembly prototype under the conditions from reactor start-up to low-power operation.

[0058] Furthermore, the flow rate and temperature of the saturated water circulation loop and the feed water circulation loop are adjusted in a coordinated manner, including:

[0059] S11. Inject demineralized water into the saturated water circulation loop and establish the water level of the pressure stabilization system. Turn on the power supply of the pressure stabilization system to heat and pressurize to the test pressure.

[0060] S12. Add demineralized water to the saturated water circulation loop until the saturated water circulation loop reaches the test pressure, then shut down the demineralized water supply system;

[0061] S13. Turn on the main circulation pump and adjust the flow rate in the saturated water circulation loop to the test flow rate;

[0062] S14. Introduce steam into the heat source heat exchanger to heat the saturated water circulation loop to the test temperature;

[0063] S15. Start the feedwater circulation pump and adjust the feedwater circulation loop flow rate to the rated feedwater flow rate so that the feedwater heat exchanger cools the feedwater to the rated temperature.

[0064] During the test, the first valve 109, the shut-off valve 104, the electric regulating valve 103, and the third valve 115 are opened. Demineralized water is injected into the test circuit through the demineralized water supply system 107. After the residual gas is discharged through the exhaust valve at the top of the steam generator container simulation device 101, the water level of the pressure regulator 102 is established. The shut-off valve 104 is closed to disconnect the pressure regulator 102, and the power supply to the pressure regulator 102 is turned on to heat and pressurize to the test pressure. Water is continuously added to pressurize the circuit to the test pressure, and the first valve 109 is closed. The shut-off valve 104 is opened to connect the pressure regulator 102, the main circulation pump 111 is turned on, and the flow rate of the saturated water circulation circuit is adjusted to the test flow rate. The electric regulating valve 106 of the steam pipeline is opened to introduce steam into the heat source heat exchanger 105 to heat the saturated water circulation circuit to the test temperature. Saturated water is injected from the top of the steam generator container simulation device 1, and after being diverted by the ellipsoidal head of the inner cylinder, it enters the gap between the inner and outer cylinders.

[0065] The feedwater circulation pump 112 is started, and the feedwater circulation loop flow rate is adjusted to the rated feedwater flow rate through the third valve 115. The feedwater is cooled to the rated temperature through the feedwater heat exchanger 113. The feedwater enters the steam generator vessel simulation device 101 through the feedwater assembly, realizing the flow distribution of the feedwater. After the feedwater and saturated water are mixed, they are diverted through the ellipsoidal head of the inner cylinder of the vessel and flow downward along the gap, flowing out from the water outlet pipe at the bottom of the vessel. By linking the flow rate and temperature of the saturated water circulation loop and the feedwater circulation loop, the steady-state temperature field of the feedwater assembly prototype under low-power steady-state conditions can be simulated; as well as the transient temperature field of the feedwater assembly prototype under the conditions from reactor start-up to low-power operation.

[0066] Specifically, refer to Figure 1-6 As shown, the steam generator vessel simulation device includes a main body; the main body includes:

[0067] Pressure-bearing outer cylinder;

[0068] The inner cylinder is located inside the pressure-bearing outer cylinder;

[0069] The inner cylinder hoisting assembly is located inside the pressure-bearing outer cylinder and is used for hoisting the inner cylinder.

[0070] Water inlet pipe 4 is located at one end of the pressure-bearing outer cylinder and is used to supply saturated water;

[0071] Water outlet pipe 14 is located at the other end of the pressure-bearing outer cylinder and is used for water outlet;

[0072] Water supply assembly 1, used for supplying water to the pressure-bearing outer cylinder, is located near the gap in the pressure-bearing outer cylinder;

[0073] Temperature measuring component 2 is used to measure the temperature distribution of the water flowing into the gap;

[0074] The water flows from the inlet pipe along the gap between the inner wall of the pressure-bearing outer cylinder and the outer wall of the inner cylinder to the outlet pipe.

[0075] refer to Figure 1 As shown, the main body of the device includes a pressure-bearing outer cylinder and an inner cylinder. An inner cylinder hoisting assembly is located on the top inner side of the pressure-bearing outer cylinder for hoisting the inner cylinder. A manhole is located on the upper right side of the pressure-bearing outer cylinder. A water inlet pipe is located at the upper end of the pressure-bearing outer cylinder. Water enters the pressure-bearing outer cylinder through the water inlet pipe. A gap is formed between the outer wall of the inner cylinder and the inner wall of the pressure-bearing outer cylinder. A water supply assembly is located on the pressure-bearing outer cylinder near the gap for water intake. Specifically, hot water enters through the water inlet pipe, and cold water enters through the water supply assembly. This creates a temperature distribution area within the gap. The temperature distribution within this area is measured by a temperature measuring assembly, thereby achieving a realistic simulation of the steady-state and transient thermo-hydraulic characteristics inside the steam generator and meeting the real-time online monitoring requirements for the thermal stratification test of the water supply assembly.

[0076] Therefore, in this embodiment of the invention, the pressure-bearing outer cylinder and the inner cylinder form a gap between the inner wall of the pressure-bearing outer cylinder and the outer wall of the inner cylinder. This gap allows hot water entering through the inlet pipe and cold water entering through the water supply assembly to form a temperature distribution area of ​​hot and cold water. By using a temperature measuring component to monitor the temperature distribution in the area near the water supply assembly and on the outer and inner walls of the water supply assembly located in the gap between the inner and outer walls of the pressure-bearing outer cylinder, a true simulation of the steady-state and transient thermo-hydraulic characteristics of the steam generator within the full power range is achieved, meeting the real-time online monitoring requirements for the thermal stratification test of the water supply assembly.

[0077] Furthermore, the pressure-bearing outer cylinder is equipped with a water inlet distributor, which is connected to the water inlet pipe; the water inlet distributor is a frame structure with an opening on one side; the opening side of the water inlet distributor 16 is connected to the water inlet pipe; each side and bottom of the water inlet distributor is provided with several openings.

[0078] The water distributor has a flow distribution hole diameter of 20mm, with 5 rows of 180 flow distribution holes on the side; the bottom plate has 109 flow distribution holes, which are arranged in a triangular shape.

[0079] Furthermore, the plurality of openings includes a plurality of opening units; each opening unit contains three openings arranged in an equilateral triangle.

[0080] refer to Figure 4 As shown, the three openings of each equilateral triangle form a 60° angle.

[0081] Furthermore, the temperature measuring component is arranged in multiple concentric circles, with temperature measuring elements distributed on each concentric circle.

[0082] Furthermore, the multi-layer concentric circles are evenly distributed with 1, 3, 6, 6, 12 and 12 temperature sensing elements from the inside to the outside, respectively; the insertion depth of the temperature sensing elements on the inner concentric circles to the outer concentric circles is successively shallow to deep.

[0083] refer to Figure 5 and 6 As shown, a temperature sensing assembly integrates 40 temperature sensing elements, arranged in six concentric circles. From the inside out, each layer contains 1, 3, 6, 6, 12, and 12 temperature sensing elements respectively. Since the temperature sensing elements need to be tightened at the top with a wrench when encapsulating and removing thermocouples, the height of the temperature sensing elements is designed to decrease sequentially from the inside out. This allows for the placement of as many temperature sensing elements as possible within a small space without affecting the installation and removal of thermocouples.

[0084] Furthermore, the pressure-bearing outer cylinder is provided with a manhole 3.

[0085] Furthermore, the inner cylinder hoisting assembly includes an inner cylinder hoisting rod 15 disposed on the inner wall of the pressure-bearing outer cylinder; the inner cylinder is provided with an inner cylinder hoisting ring 17 for connecting with the inner cylinder hoisting rod.

[0086] Furthermore, the inner cylinder includes:

[0087] The movable section 7 of the inner cylinder, together with the fixed section of the inner cylinder via the inner cylinder positioning device 8, forms the inner cylinder.

[0088] The inner cylinder fixing section 10 has an inner cylinder support ring plate 11 at its bottom; the inner cylinder support ring plate is used to contact the inner wall of the pressure-bearing outer cylinder to form support for the inner cylinder.

[0089] The inner cylinder lifting ring is located in the movable section of the inner cylinder.

[0090] The double-layered container structure and the expandable inner cylinder of this invention enable the simulation device to not only realistically simulate the secondary thermal-hydraulic characteristics of the steam generator but also to arrange and install a real-time monitoring device for thermal stratification of the feedwater assembly. Thus, it achieves the simulation of complex experimental conditions for thermal stratification of the feedwater assembly with a relatively simple structural form.

[0091] Furthermore, the pressure-bearing outer cylinder is composed of an upper straight cylinder section 5, an inclined cone section 6, and a lower straight cylinder section 9 connected together; the temperature measuring component is located in the upper straight cylinder section; the water supply component is located in the inclined cone section; and the water outlet pipe is located in the lower straight cylinder section.

[0092] Furthermore, the water outlet pipe is connected to a water outlet line 13; a skirt seat 12 is provided on the outer side of the pressure-bearing outer cylinder.

[0093] The design of the water inlet distributor in this embodiment of the invention makes the flow field in the upper space of the steam generator feedwater assembly thermal stratification test body uniform, reduces the problem of excessive flow velocity caused by direct water inlet pipe, and reduces the generation of vortices; 2. The segmented liftable inner cylinder structure design can realize the simulation of the secondary side descending channel of the prototype steam generator, and can also increase the construction and maintenance space through the descendable straight cylinder section, realizing the installation and replacement of temperature measuring points; 3. The design of the inner cylinder hanging rod and lifting ring, together with the electric hoist, can realize the free lifting and lowering of the inner cylinder moving section; 4. The staggered temperature measuring element arrangement allows the temperature measuring assembly to introduce a sufficient number of thermocouples in a small space.

[0094] The installation method of the simulation device in this embodiment of the invention includes the following steps: 1. First, complete the welding of the lower end cap, lower straight edge section, and inclined cone section; 2. Perform butt welding of the inclined cone section and the central section of the water supply component; 3. Perform welding of the upper straight edge section and inclined cone section and assembly of the temperature measuring component; 4. Install the inner cylinder and lower the movable section of the inner cylinder to its lowest position; 5. Use the temperature measuring component to pull the thermocouple into the container, and the workers enter the cylinder and enter the construction platform of the movable section of the inner cylinder to weld the temperature measuring points of the water supply component; 6. On the construction platform of the inner cylinder, the workers use an electric hoist in conjunction with the inner cylinder lifting rod and lifting ring to raise the movable section of the inner cylinder to its highest position, and then remove the hoist and leave the container through the manhole; 7. Perform welding of the upper end cap. When the temperature monitoring point of the water supply component is damaged, the workers enter the container through the manhole of the upper end cap and replace the temperature measuring point according to steps 4, 5, and 6 above.

[0095] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thermal stratification test system for a steam generator feedwater assembly, characterized in that, include: Steam generator vessel simulation device, heat source heat exchanger, main circulation pump, feedwater circulation pump and feedwater heat exchanger; The steam generator vessel simulation device includes a main body, which comprises: Pressure-bearing outer cylinder; The inner cylinder is located inside the pressure-bearing outer cylinder, and a gap is formed between the outer wall of the inner cylinder and the inner wall of the pressure-bearing outer cylinder. The inner cylinder hoisting assembly is located inside the pressure-bearing outer cylinder and is used for hoisting the inner cylinder. The water inlet pipe is located at one end of the pressure-bearing outer cylinder and is used to supply saturated water. The water outlet pipe is located at the other end of the pressure-bearing outer cylinder and is used for water outlet. A water supply assembly for supplying water to the pressure-bearing outer cylinder, located near the gap in the pressure-bearing outer cylinder; Temperature sensing components are used to measure the temperature distribution of the water flowing into the gap; The saturated water flows from the inlet pipe along the gap between the inner wall of the pressure-bearing outer cylinder and the outer wall of the inner cylinder to the outlet pipe; The inlet pipe, heat source heat exchanger, main circulation pump, and outlet pipe of the steam generator container simulation device are connected in sequence to form a saturated water circulation loop. The water supply components, water supply heat exchanger, water supply circulation pump, and water outlet pipe of the steam generator container simulation device are connected by pipelines to form a water supply circulation loop.

2. The steam generator feedwater assembly thermal stratification test system as described in claim 1, characterized in that, The saturated water circulation loop is also connected to a demineralized water supply system and a pressure stabilizing system; the demineralized water supply system is connected to the saturated water circulation loop through a first valve.

3. The steam generator feedwater assembly thermal stratification test system as described in claim 2, characterized in that, The demineralized water supply system is connected to the heat source heat exchanger via a first valve and a first flow meter.

4. The steam generator feedwater assembly thermal stratification test system as described in claim 3, characterized in that, The main circulation pump is connected to the first flow meter through the second valve.

5. The steam generator feedwater assembly thermal stratification test system as described in claim 4, characterized in that, The voltage stabilizing system includes: The pressure regulator is connected to the inlet pipe of the steam generator vessel simulation device via an electric regulating valve and a shut-off valve.

6. The steam generator feedwater assembly thermal stratification test system as described in any one of claims 3-5, characterized in that, The water supply heat exchanger is connected to the water supply component of the steam generator container simulation device via a second flow meter and a third valve.

7. The steam generator feedwater assembly thermal stratification test system as described in claim 6, characterized in that, The first valve is a stop valve; the second valve is a check valve; and the third valve is an electric regulating valve.

8. The thermal stratification test system for the steam generator feedwater assembly as described in claim 1, characterized in that, The heat source heat exchanger is equipped with an electric regulating valve for the steam pipeline.

9. A test method based on the thermal stratification test system for the steam generator feedwater assembly according to any one of claims 2-8, characterized in that, include: The flow and temperature of the saturated water circulation loop and the feedwater circulation loop are linked to achieve the simulation of the steady-state temperature field of the feedwater assembly prototype in the steam generator vessel simulation device under low-power steady-state conditions, as well as the simulation of the transient temperature field of the feedwater assembly prototype under the conditions from start-up to low-power operation.

10. The test method as described in claim 9, characterized in that, The flow and temperature of the saturated water circulation loop and the feed water circulation loop are linked and adjusted, including: Inject demineralized water into the saturated water circulation loop and establish the water level of the pressure stabilization system. Turn on the power supply of the pressure stabilization system to heat and pressurize to the test pressure. Add demineralized water to the saturated water circulation loop until the saturated water circulation loop reaches the test pressure, then shut down the demineralized water supply system. Turn on the main circulation pump and adjust the flow rate in the saturated water circulation loop to the test flow rate; Steam is introduced into the heat source heat exchanger to heat the saturated water circulation loop to the test temperature; Turn on the feedwater circulation pump and adjust the feedwater circulation loop flow rate to the rated feedwater flow rate so that the feedwater heat exchanger cools the feedwater to the rated temperature.

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