Integrated small reactor passive residual heat removal test heat exchange structure, system and method

Abstract

The embodiment of the invention provides an integrated small reactor passive residual heat removal test heat exchange structure, system and method, and relates to the technical field of nuclear reactor safety system tests. The system aims to solve the problems that in an integrated small reactor passive quay crane test system, split type and pipeline connection are adopted for containment cooling, so that the system is tedious and large in occupied space. And the heat exchange structure is directly connected with the containment simulation device and the cooling water tank through the shared heat exchange part. The test system comprises the test heat exchange structure, and the test method is implemented by adopting the test system. And heat is transferred from the high-temperature containment simulation device to the low-temperature cooling water tank fluid through the heat exchange part. Redundant connecting parts of the common heat exchange part are omitted, and occupied space is reduced. Efficient and rapid heat transfer is achieved, waste heat is discharged in time, safety is guaranteed, and due to the compact structural design, the whole test device is more reasonable in layout, saves space and is convenient to install, debug and maintain.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor safety system testing technology, and more specifically, to an integrated small modular reactor passive residual heat removal test heat exchange structure, system, and method. Background Technology

[0002] The Passive Residual Heat Removal System (PRHRS) is a typical passive safety system used in advanced pressurized water reactors. Its main function is to automatically remove core residual heat without relying on external power or active drive equipment in the event of a plant-wide power outage or failure of the reactor's normal residual heat removal system, thus ensuring the safety of the reactor system. The passive safety design concept is a major highlight of third-generation reactors. Research on the design and performance of passive residual heat removal systems is of great significance to the development of the nuclear power industry. This research can verify the reliability and adaptability of passive systems driven by natural forces, laying a solid experimental foundation for nuclear safety and serving as a key prerequisite for the practical application of advanced reactors.

[0003] The integrated small modular reactor (SMR) with full natural circulation integrates key equipment such as the reactor core and main heat exchanger into a single pressure vessel, relying on the density difference between the hot and cold media within the pressure vessel to create natural circulation. This passive design concept and compact structure not only reduce the complexity of the reactor system and piping connections but also improve the system's reliability and safety, making it of significant application value in the field of nuclear heating. Performance research and verification of the passive safety system of this type of integrated SMR are crucial for its development and application.

[0004] However, current containment cooling systems often employ independent external cooling systems, such as additional cooling coils, spray systems, or secondary circulation loops. These systems are typically complex, space-consuming, and have lengthy heat exchange paths. This makes the device itself bulky, cumbersome, and inefficient, failing to embody the compact and efficient design philosophy of integrated small modular reactors (SMRs) and increasing testing costs. Summary of the Invention

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] The objectives of this invention include, for example, providing an integrated small modular reactor (SMR) passive residual heat removal test heat exchange structure, system, and method that can improve the problems of system redundancy and large space occupation caused by the use of separate cooling and pipeline connections in the containment cooling of the integrated SMR passive quay crane test system.

[0007] The embodiments of the present invention can be implemented as follows: An embodiment of the present invention provides an integrated passive residual heat removal test heat exchange structure for small modular reactors, including a containment simulation device and a cooling water pool; the cooling water pool and the containment simulation device are directly connected in the heat exchange area through a shared heat exchange section, so that the fluid inside the cooling water pool can cool the containment simulation device through the heat exchange section.

[0008] In addition, the integrated small modular reactor passive waste heat removal test heat exchange structure provided in the embodiments of the present invention may also have the following additional technical features: Optionally, the outer shell of the cooling water pool and the outer shell of the containment simulation device are connected in the heat exchange area through a structural fusion process to form the common heat exchange section.

[0009] Optionally, the structural fusion process can be welding or bonding using a high thermal conductivity medium.

[0010] Optionally, the outer shell of the cooling water pool and the outer shell of the containment simulation device are fitted together by a mutually cooperating concave-convex structure to form the common heat exchange section.

[0011] Embodiments of the present invention also provide an integrated passive residual heat removal test system for small modular reactors, comprising: an integrated passive residual heat removal test heat exchange structure for small modular reactors, a pressure vessel simulation device, and at least one passive residual heat removal branch; the pressure vessel simulation device is internally provided with a heating unit for simulating the core heat source; the passive residual heat removal branch includes a closed-loop circulation circuit and an internal heat exchanger and a passive removal heat exchanger disposed on the closed-loop circulation circuit, the internal heat exchanger being disposed inside the pressure vessel simulation device, and the passive removal heat exchanger being disposed inside the cooling water pool; the center arrangement height of the passive removal heat exchanger is higher than the center arrangement height of the internal heat exchanger, so as to form a positional difference driving the circulation of the working fluid within the passive residual heat removal branch.

[0012] Optionally, the height difference between the center arrangement of the passive exhaust heat exchanger and the center arrangement of the internal heat exchanger is H, where H ranges from 300 mm to 580 mm.

[0013] Optionally, the height difference H = 380 mm.

[0014] Optionally, the heat transfer tubes of the internal heat exchanger are arranged in a vertically oriented tube bundle structure.

[0015] Optionally, there are two passive waste heat discharge branches, and the two internal heat exchangers are symmetrically arranged inside the pressure vessel simulation device.

[0016] Optionally, the passive waste heat discharge branch further includes a normally closed switching valve disposed on the closed loop, the normally closed switching valve being used to open under simulated accident conditions to trigger the passive waste heat discharge test system.

[0017] Optionally, the test system further includes a cooling water tank heat exchange branch; the cooling water tank heat exchange branch includes a branch and a circulating pump and a cooling water heat exchanger installed on the branch, and the branch is connected to the cooling water tank end to end to form a loop.

[0018] Embodiments of the present invention also provide an integrated passive residual heat removal test method for small modular reactors, implemented using an integrated passive residual heat removal test system for small modular reactors, comprising the following steps: The heating unit is activated to simulate reactor operation and post-accident decay heat. In the event of an accident, the passive residual heat removal branch is activated, and heat circulation occurs between the internal heat exchanger and the passive heat removal heat exchanger to transfer the simulated core heat to the cooling water pool. Simultaneously, the heat from the containment simulation device is transferred to the fluid in the cooling water pool through the common heat exchange section.

[0019] The beneficial effects of the integrated small modular reactor passive residual heat removal test heat exchange structure, system, and method according to embodiments of the present invention include, for example: The integrated heat exchange structure for passive residual heat removal testing of a small modular reactor (SMR) includes a containment simulator and a cooling water tank. The cooling water tank and containment simulator are directly connected in the heat exchange area via a shared heat exchange section, allowing the fluid inside the cooling water tank to cool the containment simulator through this section. Heat is transferred from the high-temperature containment simulator to the low-temperature cooling water fluid using heat conduction. This direct heat transfer connection reduces intermediate steps in heat transfer, lowers thermal resistance, and enables rapid and efficient heat removal from the containment simulator, preventing heat accumulation and effectively ensuring the safety of the device under simulated operating conditions, thus improving the reliability and accuracy of the test. Furthermore, it effectively reduces size and space requirements, achieving a compact structure.

[0020] The integrated small modular reactor passive residual heat removal test system, including the aforementioned heat exchange structure, can improve the problem of system redundancy and large space occupation caused by the separate containment cooling and pipeline connection in the integrated small modular reactor passive quay crane test system.

[0021] The passive residual heat removal test method for integrated small modular reactors, implemented using the above-mentioned test system, can improve the problem of system redundancy and large space occupation caused by the separate cooling and piping connection of the containment in the passive quay crane test system for integrated small modular reactors. Attached Figure Description

[0022] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0023] Figure 1 The structural block diagram of the integrated small modular reactor passive residual heat removal test system provided in the embodiment of the present invention is shown.

[0024] Icons: Integrated Small Reactor Passive Residual Heat Removal Test Heat Exchange Structure-10; Containment Simulation Device-100; Cooling Water Pool-110; Common Heat Exchanger-120; Integrated Small Reactor Passive Residual Heat Removal Test System-20; Pressure Vessel Simulation Device-210; Small Reactor Pressure Vessel-211; Heating Unit-220; Electric Heating Rod-221; Internal Heat Exchanger-230; Passive Residual Heat Removal Branch-300; Circulation Closed Loop-310; First Shut-off Valve-321; Normally Closed Switch Valve-322; Passive discharge heat exchanger-360; outlet pipeline flow meter-323; normally open switch valve-324; second shut-off valve-325; cooling water pool heat exchange branch-400; branch-401; connecting shut-off valve-411; filter-412; circulating pump-414; cooling water heat exchanger-413; plate heat exchanger-422; cooling water flow meter-423; cooling water regulating valve-424; cooling water switch valve-425; cooling water shut-off valve-426; steam pressure regulator-800; pressure regulator heating rod-810. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0026] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," "outer," or "vertical" appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, and does 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, and therefore should not be construed as a limitation of this invention.

[0027] At the same time, it should be noted that the terms "first" and "second" are used only for distinguishing descriptions and should not be interpreted as indicating or implying relative importance.

[0028] The following is combined with Figure 1 The integrated small reactor passive waste heat removal test heat exchange structure 10 provided in this embodiment is described in detail.

[0029] Please refer to Figure 1 An embodiment of the present invention provides an integrated passive residual heat removal test heat exchange structure 10 for small reactors, including a containment simulation device 100 and a cooling water pool 110; the cooling water pool 110 and the containment simulation device 100 are directly connected in the heat exchange area through a shared heat exchange section 120, so that the fluid inside the cooling water pool 110 can cool the containment simulation device 100 through the heat exchange section.

[0030] The cooling water tank 110 and the containment simulation device 100 are directly connected by a shared heat exchange section 120 in the heat exchange area. Heat is transferred from the higher-temperature containment simulation device 100 to the lower-temperature fluid inside the cooling water tank 110 through the shared heat exchange section 120, achieving a cooling function. This direct heat transfer connection reduces intermediate thermal resistance links, and compared with traditional indirect heat exchange methods, it can more efficiently transfer heat from the containment simulation device 100, improve waste heat removal efficiency, and ensure the safety of the integrated small modular reactor under accident conditions. Furthermore, the integrated and compact design of the cooling water tank 110 and the containment simulation device 100 through the shared heat exchange section 120 simplifies the heat exchange pipelines and equipment between the two devices, saving both cost and on-site space.

[0031] The heat exchange section 120 uses the same material, such as a metal material with high thermal conductivity, to further improve heat transfer efficiency.

[0032] Reference Figure 1 In this embodiment, the outer shell of the cooling water tank 110 and the outer shell of the containment simulation device 100 are connected in the heat exchange area by a structural fusion process to form a common heat exchange section 120.

[0033] The cooling water tank 110 and the containment simulation device 100 are connected in the heat exchange area using a structural fusion process to form a shared heat exchange section 120. This fusion process ensures a tight connection between the two, reducing contact thermal resistance. This tight connection reduces heat loss during transfer, further improving heat transfer efficiency and ensuring that the cooling water tank 110 can more effectively absorb heat from the containment simulation device 100, thus enhancing the system's safety and reliability. Furthermore, it simplifies the structure and improves construction efficiency.

[0034] In this embodiment, the structural fusion process is welding or bonding through a high thermal conductivity medium.

[0035] Welding uses high temperatures to melt metals and achieve a connection, while high thermal conductivity bonding uses a medium with high thermal conductivity to bond two components together, both achieving a tight connection. Both processes effectively reduce contact thermal resistance and improve heat transfer efficiency. Welding provides high connection strength and good stability; high thermal conductivity bonding is relatively simple to operate and suitable for scenarios where connection strength requirements are not extremely high but rapid installation is needed.

[0036] Reference Figure 1 In this embodiment, the outer shell of the cooling water tank 110 and the outer shell of the containment simulation device 100 are fitted together by a mutually cooperating concave-convex structure to form a common heat exchange section 120.

[0037] The concave-convex structure increases the contact area between the two components, while the tight fit reduces air gaps. Increasing the contact area and reducing air gaps effectively lowers contact thermal resistance, improves heat transfer efficiency, and allows the cooling water tank 110 to absorb heat from the containment simulation device 100 more quickly, thereby enhancing the system's waste heat removal capacity.

[0038] It should be noted that in this embodiment, the "fitting by mutually cooperating concave and convex structures" can be implemented in various ways. The concave outer shell of the cooling water tank 110 can be fitted with the convex outer shell of the containment simulation device 100, or the convex outer shell of the first cooling water tank 110 can be fitted with the concave outer shell of the containment simulation device 100, or the gap between the outer shell of the cooling water tank 110 and the outer shell of the containment simulation device 100 can be connected by welding or bonding, or the outer shell of the cooling water tank 110 and the outer shell of the containment simulation device 100 can be connected by welding or bonding outside the concave and convex structures.

[0039] Reference Figure 1The present invention also provides an integrated passive residual heat removal test system 20 for small modular reactors, comprising: an integrated passive residual heat removal test heat exchange structure 10, a pressure vessel simulation device 210, and at least one passive residual heat removal branch 300; the pressure vessel simulation device 210 is internally provided with a heating unit 220 for simulating the core heat source; the passive residual heat removal branch 300 includes a closed loop 310 and an internal heat exchanger 230 and a passive removal heat exchanger 360 disposed on the closed loop 310, the internal heat exchanger 230 being disposed inside the pressure vessel simulation device 210, and the passive removal heat exchanger 360 being disposed inside the cooling water pool 110; the center arrangement height of the passive removal heat exchanger 360 is higher than the center arrangement height of the internal heat exchanger 230, so as to form a positional difference driving the circulation of the working fluid within the passive residual heat removal branch 300. Specifically, the internal heat exchanger 230 is a built-in large coil heat exchanger. The pressure vessel simulation device 210 is a small reactor pressure vessel 211. The heating unit 220 is an electric heating rod 221.

[0040] The internal heating unit 220 of the pressure vessel simulation device 210 simulates the core heat source to generate heat. The passive residual heat removal branch 300 utilizes the elevation difference to generate the driving force for the working fluid circulation. The internal heat exchanger 230 absorbs the heat inside the pressure vessel simulation device 210, and the passive heat removal heat exchanger 360 transfers the heat to the cooling water pool 110. By simulating the heat generation and transfer process under actual reactor operation and accident conditions, the performance of the integrated small modular reactor passive residual heat removal system can be comprehensively and realistically tested, verifying whether the system can effectively remove residual heat under accident conditions and ensure reactor safety.

[0041] Reference Figure 1 In this embodiment, the pressure vessel simulation device 210 is also equipped with a steam pressure regulator 800. Multiple pressure regulator heating rods 810 are provided, and when the small reactor triggers an accident sequence, all pressure regulator heating rods 810 are shut down.

[0042] In this embodiment, the height difference between the center arrangement of the passive exhaust heat exchanger 360 and the center arrangement of the internal heat exchanger 230 is H, and the range of H is 300MM-580MM.

[0043] A suitable height difference provides sufficient driving force to ensure stable circulation of the working fluid in the loop and effective heat transfer. If the height difference is too small, the driving force is insufficient, and the working fluid circulation is not smooth; if the height difference is too large, it may increase the system construction and operating costs.

[0044] Reference Figure 1 In this embodiment, the height difference H = 380 mm.

[0045] Under this specific height difference, the working fluid in the integrated small reactor passive residual heat removal test system 20 can circulate in the loop at a suitable flow rate, ensuring the stability and efficiency of heat transfer between the internal heat exchanger 230 and the passive heat removal heat exchanger 360, so that the system can effectively remove residual heat under simulated accident conditions.

[0046] Reference Figure 1 In this embodiment, the heat transfer tubes of the internal heat exchanger 230 are arranged in a vertical tube bundle structure. Figure 1 The diagram illustrates a horizontally arranged tube bundle structure. A vertically arranged tube bundle structure would be even more effective.

[0047] The heat transfer tubes of the internal heat exchanger 230 adopt a vertically arranged tube bundle structure. This allows the working fluid to better absorb heat during its ascent and carry it away during its descent, forming a good natural circulation and improving the heat transfer efficiency of the internal heat exchanger 230, thereby enhancing the performance of the entire passive waste heat removal system. Furthermore, the vertical arrangement reduces the space occupied by the heat transfer tubes, enabling a compact passive waste heat removal test system.

[0048] Reference Figure 1 In this embodiment, there are two passive waste heat discharge branches 300, and two internal heat exchangers 230 are symmetrically arranged inside the pressure vessel simulation device 210. The two internal heat exchangers 230 are internal heat exchanger A 230 and internal heat exchanger B 230.

[0049] The symmetrically arranged internal heat exchanger 230 can absorb heat more evenly within the pressure vessel simulation device 210, avoiding local overheating; the simultaneous operation of the two loops increases the heat transfer channels, improves the redundancy and reliability of the system's residual heat removal, and better ensures reactor safety under accident conditions.

[0050] Reference Figure 1 In this embodiment, the passive waste heat discharge branch 300 also includes a normally closed switch valve 322 disposed on the closed loop 310. The normally closed switch valve 322 is used to open under the accident simulation condition to trigger the passive waste heat discharge test system.

[0051] A normally closed switch valve 322 is installed on the passive residual heat removal branch 300. This valve opens under simulated accident conditions, triggering the valve's action using an accident signal, thereby activating the passive residual heat removal test system. The normally closed switch valve 322 ensures the system remains closed during normal operation, reducing unnecessary energy loss; under accident conditions, it opens rapidly, promptly activating the passive residual heat removal system to quickly remove residual heat, ensuring reactor safety and improving the system's response speed and safety.

[0052] Reference Figure 1In this embodiment, the passive waste heat discharge branch 300 is also equipped with a first shut-off valve 321, an outlet pipeline flow meter 323, a normally open isolation valve, and a second shut-off valve 325. The first shut-off valve 321, the normally closed switch valve 322, the passive discharge heat exchanger 360, the outlet pipeline flow meter 323, the normally open switch valve 324, and the second shut-off valve 325 are arranged sequentially along the closed loop 310.

[0053] Reference Figure 1 In this embodiment, the test system further includes a cooling water tank heat exchange branch 400; the cooling water tank heat exchange branch 400 includes a branch 401 and a circulating pump 414 and a cooling water heat exchanger 413 installed on the branch 401. The branch 401 and the cooling water tank 110 are connected end to end to form a loop. Specifically, the cooling water heat exchanger 413 is a plate heat exchanger 422.

[0054] Cooling water is driven by circulating pump 414 to circulate in branch 401, and exchanges heat with the external environment through cooling water heat exchanger 413, thereby reducing the water temperature of cooling water pool 110. Cooling water pool heat exchange branch 400 can promptly discharge the heat absorbed by cooling water pool 110 to the external environment, keeping the water temperature of cooling water pool 110 within a suitable range, avoiding the impact of excessively high water temperature on the cooling effect of containment simulation device 100 and pressure vessel simulation device 210, and improving the stability and reliability of the entire test system.

[0055] Reference Figure 1 In this embodiment, the cooling water tank heat exchange branch 400 is also equipped with a connecting stop valve 411, a filter 412, a cooling water flow meter 423, a cooling water regulating valve 424, a cooling water on / off valve 425, and a stop valve. The two ends of the branch 401 are connected to the outlet and inlet of the cooling water tank 110, respectively. The connecting stop valve 411, filter 412, circulating pump 414, cooling water heat exchanger 413, cooling water flow meter 423, cooling water regulating valve 424, cooling water on / off valve 425, and cooling water stop valve 426 are arranged in sequence.

[0056] In this embodiment, the system loop medium is deionized water. The system loop is connected using 304 stainless steel pipes. All regulating and switching valves involved in the system are pneumatic valves. Pneumatic valves offer rapid response, are suitable for emergency shut-off or high-frequency operation, and facilitate rapid operation and response during testing and verification. The regulating valves provide pipeline flow regulation, and the switching valves provide pipeline system isolation.

[0057] Embodiments of the present invention also provide an integrated small modular reactor (SMR) passive residual heat removal test method, implemented using an integrated SMR passive residual heat removal test system 20, comprising the following steps: The heating unit 220 is activated to simulate reactor operation and post-accident decay heat. In the event of an accident, the passive residual heat removal branch 300 is activated, and heat circulation occurs between the internal heat exchanger 230 and the passive heat removal heat exchanger 360 to transfer the simulated core heat to the cooling water pool 110. Simultaneously, the heat from the containment simulation device 100 is transferred to the fluid in the cooling water pool 110 through the common heat exchange section 120.

[0058] First, the heating unit 220 is activated to simulate reactor operation and post-accident decay heat. Upon the occurrence of an accident, the passive residual heat removal branch 300 is activated to initiate heat circulation. Simultaneously, heat from the containment simulation device 100 is transferred to the cooling water pool 110 via the shared heat exchanger 120. This comprehensively simulates the heat generation and transfer process of the integrated small modular reactor (SMR) under accident conditions, accurately testing the performance of the passive residual heat removal system and verifying its ability to effectively remove residual heat under accident conditions. This provides a reliable basis for the design and safety assessment of the SMR.

[0059] The principle of the integrated small modular reactor (SMR) passive residual heat removal test heat exchange structure 10, system, and method provided in this embodiment includes: it can be used to conduct passive residual heat removal test research and system optimization work for small modular reactors with full natural circulation heating. Through this system, experimental data support can be accumulated for the safety characteristic research of integrated small modular reactors with full natural circulation heating, the optimization of passive core cooling system design, and the development and verification of safety analysis programs.

[0060] The small reactor pressure vessel 211 has an integrated and compact layout. Electric heating rods 221 are arranged at the bottom, and the heating power of the electric heating rods 221 is used to simulate the core heating power. It has two symmetrical internal heat exchangers 230 with a spiral winding structure. A steam pressurizer 800 is built into the top. Four sets of pressurizer heating rods 810 are arranged around the pressurizer (0°, 90°, 180°, 270°) to provide heating power and pressure stabilization function for the steam pressurizer 800.

[0061] The passive waste heat discharge branch 300 is divided into two columns. In each column, the medium flows out from the outlet side of the corresponding internal heat exchanger 230, passes through the first shut-off valve 321 and the normally closed switch valve 322 installed on the pipeline, and flows into the inlet side of the corresponding column's passive waste heat discharge heat exchanger 360. Then, it flows out through the outlet side of the corresponding column's passive waste heat discharge heat exchanger 360 to the outlet pipeline flow meter 323. Downstream of the outlet pipeline flow meter 323, a normally open switch valve 324 and a second shut-off valve 325 are arranged, and finally, it flows into the inlet side of the corresponding column's small stack internal large coil heat exchanger, completing the natural circulation of the corresponding column's passive waste heat discharge branch 300. The medium flow path of the other column's passive waste heat discharge branch 300 is the same and will not be described further.

[0062] The cooling water tank 110 contains two symmetrical passive discharge heat exchangers 360, which are immersed in the water level of the cooling water tank 110. The medium in the cooling water tank heat exchange branch 400 flows through the bottom of the cooling water tank 110, connecting to the shut-off valve 411 and the cooling water filter 412, before flowing into the inlet of the circulating pump 414. Driven by the circulating pump 414, it flows out to the inlet of the cooling water heat exchanger 413, and then through the outlet of the cooling water heat exchanger 413, connecting to the cooling water flow meter 423, the cooling water regulating valve 424, the cooling water on / off valve 425, and the cooling water shut-off valve 426 before returning to the cooling water tank 110. The flow rate of the cooling water tank heat exchange branch 400 is regulated by the cooling water regulating valve 424 and the frequency of the cooling water circulating pump 414, while the temperature of the medium in the loop is controlled by the cooling water heat exchanger 413.

[0063] The containment vessel and the cooling water tank 110 are integrated into an envelope structure, sharing a heat exchange condensation surface. The cooling water tank 110 encloses part of the outer wall of the containment vessel, thereby realizing the heat exchange function of the containment vessel and the cooling water tank 110. The two adopt an integrated and compact design, which simplifies the heat exchange pipelines and equipment between the two devices, saving not only costs but also space on site.

[0064] When the small reactor triggers an accident sequence, all pressurizer heating rods 810 are shut down. The electric heating rods 221 at the bottom of the small reactor pressure vessel 211, which simulate the core heating power, trigger the decay heat power curve to reduce the core heating power. The normally closed switch valve 322 on the passive residual heat removal system pipeline is automatically triggered to open quickly. Using the principle of natural circulation, the residual heat of the core is discharged to the cooling water pool 110 to prevent the core from overheating.

[0065] The integrated small modular reactor passive waste heat removal test heat exchange structure 10, test system, and method provided in this embodiment have at least the following advantages: The cooling water tank 110 and the containment simulation device 100 are directly connected via a shared heat exchange section 120, reducing intermediate steps and enabling rapid heat transfer from the containment simulation device 100 to the cooling water tank 110, thus improving waste heat removal efficiency. Specifically, the cooling water tank 110 and the containment adopt an integrated, enveloping structure. This compact design simplifies heat transfer between the two, allowing them to exchange heat through a shared heat exchange condensation surface. This greatly simplifies the design and spatial arrangement of the heat exchange branch 401.

[0066] The heat exchange structure, pressure vessel simulation device 210, passive waste heat discharge branch 300, etc. constitute a complete test system, which can comprehensively simulate the passive waste heat discharge process of the integrated small reactor and provide a reliable platform for research.

[0067] In the event of a plant-wide power outage or failure of the normal heat removal path in the small reactor (SDR), a safety signal will trigger the valves of the passive residual heat removal test system to activate. Operating on the principle of natural circulation, the passive removal heat exchanger 360 and the in-reactor heat exchanger 230 have a positional and temperature difference, which generates a driving force, thus forming a natural circulation. In this circulation, the flow direction of the medium is consistent with the original flow direction on the secondary side of the in-reactor heat exchanger 230. Core heat is first transferred through the in-reactor heat exchanger 230 to the passive residual heat removal branch 300, and finally through the passive removal heat exchanger 360 to the cooling water pool 110. In this way, the steam generated in the in-reactor heat exchanger 230 can carry away the heat generated by the simulated core through the passive residual heat removal branch 300. The system's cooling water pool 110 has sufficient cooling capacity. It can regulate the temperature of the medium in the cooling water pool 110 through the cooling water pool heat exchange branch 400, thereby effectively absorbing the core heat carried out by the passive residual heat discharge branch 300 and the heat discharged to the containment.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An integrated passive waste heat removal test heat exchange structure for small modular reactors, characterized in that, include: Containment simulation device and cooling water tank; The cooling water tank and the containment simulation device are directly connected in the heat exchange area through a shared heat exchange section, so that the fluid inside the cooling water tank can cool the containment simulation device through the heat exchange section.

2. The integrated small modular reactor passive waste heat removal test heat exchange structure according to claim 1, characterized in that, The outer shell of the cooling water tank and the outer shell of the containment simulation device are connected in the heat exchange area through a structural fusion process to form the common heat exchange section.

3. The integrated small modular reactor passive waste heat removal test heat exchange structure according to claim 2, characterized in that, The structural fusion process is welding or bonding through a high thermal conductivity medium.

4. The integrated small modular reactor passive waste heat removal test heat exchange structure according to any one of claims 1-3, characterized in that, The outer shell of the cooling water tank and the outer shell of the containment simulation device are fitted together by a mutually cooperating concave-convex structure to form the common heat exchange section.

5. An integrated passive residual heat removal test system for small modular reactors, characterized in that, include: The integrated small modular reactor passive residual heat removal test heat exchange structure according to any one of claims 1-4; The system includes a pressure vessel simulation device and at least one passive waste heat discharge branch. The pressure vessel simulation device is internally equipped with a heating unit for simulating a reactor core heat source. The passive waste heat discharge branch includes a closed-loop circulation system and an internal heat exchanger and a passive discharge heat exchanger disposed on the closed-loop circulation system. The internal heat exchanger is disposed inside the pressure vessel simulation device, and the passive discharge heat exchanger is disposed inside the cooling water pool. The center height of the passive discharge heat exchanger is higher than the center height of the internal heat exchanger, creating a positional difference that drives the circulation of the working fluid within the passive waste heat discharge branch.

6. The integrated passive residual heat removal test system for small modular reactors according to claim 5, characterized in that, The height difference between the center arrangement of the passive exhaust heat exchanger and the center arrangement of the internal heat exchanger is H, and the range of H is 300MM-580MM.

7. The integrated passive residual heat removal test system for small modular reactors according to claim 6, characterized in that, The height difference H = 380 mm.

8. The integrated passive residual heat removal test system for small modular reactors according to claim 5, characterized in that, The heat transfer tubes of the internal heat exchanger are arranged in a vertically oriented tube bundle structure.

9. The integrated passive residual heat removal test system for small modular reactors according to claim 5, characterized in that, The number of passive waste heat discharge branches is two, and the two internal heat exchangers are symmetrically arranged inside the pressure vessel simulation device.

10. The integrated passive residual heat removal test system for small modular reactors according to claim 5, characterized in that, The passive waste heat discharge branch also includes a normally closed switching valve installed on the closed loop. The normally closed switching valve is used to open under simulated accident conditions to trigger the passive waste heat discharge test system.

11. The integrated small modular reactor passive residual heat removal test system according to claim 5, characterized in that, The test system also includes a cooling water tank heat exchange branch; the cooling water tank heat exchange branch includes a branch and a circulating pump and a cooling water heat exchanger installed on the branch, and the branch is connected to the cooling water tank end to end to form a loop.

12. A method for testing passive residual heat removal from an integrated small modular reactor, implemented using the integrated passive residual heat removal test system for a small modular reactor as described in any one of claims 5-11, characterized in that, Includes the following steps: The heating unit is activated to simulate reactor operation and post-accident decay heat. In the event of an accident, the passive residual heat removal branch is activated, and heat circulation occurs between the internal heat exchanger and the passive heat removal heat exchanger to transfer simulated core heat to the cooling water pool. Simultaneously, the heat from the containment simulation device is transferred to the fluid in the cooling water tank through the common heat exchange section.

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