A nuclear reactor

Abstract

The present invention relates to a nuclear reactor, comprising a reactor vessel, a heat exchange device, a drive device, and a water supply device. The reactor vessel contains liquid coolant and an air cavity. The heat exchange device is disposed within the reactor vessel, wherein the inner wall forms a first cavity for accommodating a core, and the outer and inner walls together define a second cavity. One end of the drive device is connected to the air cavity, and the other end is disposed near the core. The water supply device is in communication with the second cavity. When the nuclear reactor is operating normally, the drive device causes the average density of the liquid coolant above the top of the core to be lower than the average density of the lower cavity below the core, thereby generating a gravity difference that drives the liquid coolant to circulate within the reactor vessel, transferring heat generated by the core. When the nuclear reactor malfunctions, the circulating cold source water in the water supply device circulates in the second cavity, continuously exchanging heat with the core to remove excess heat from the core. The present invention eliminates the need for a large main pump, reduces costs, and improves the safety and reliability of the nuclear reactor.

Description

Technical Field

[0001] The present application relates to the technical field of nuclear power equipment, and in particular to a nuclear reactor. Background Art

[0002] In order to meet the power supply and heating needs of specific application scenarios (such as remote mining areas, polar scientific expeditions, emergency rescue, etc.), the international community has carried out research on small mobile nuclear reactors that are inherently safe, simple in system, and have the ability to be fully prefabricated and quickly assembled in factories. Usually, in order to facilitate the installation, fixation and transportation of the reactor, the containment vessel of the small mobile nuclear reactor is set to be cylindrical. The resulting problem is that the height difference between the reactor core and the heat exchanger is small, and the circulation capacity is weak.

[0003] When an unexpected emergency occurs in the reactor (accident condition), the normal heat removal system of the reactor cannot normally remove the heat from the primary side of the reactor and the core. The primary side of the reactor will become high temperature. In order to avoid further heating of the core and causing damage to the fuel, the decay heat generated in the reactor must be removed to prevent the pressure from running out of control. At this time, a nuclear reactor is needed to play a role, take away the heat from the primary circuit of the reactor and the core, and restore the internal pressure of the nuclear reactor containment to normal in the shortest possible time after the accident.

[0004] Most nuclear reactors in related technologies require power from an electric source and active components such as main pumps. Furthermore, due to the large resistance of a conventional reactor's primary circuit, multiple large-volume main pumps are often required to drive coolant circulation. The use of active components complicates the entire system, increases construction costs, and cannot avoid the problem of low system reliability caused by failure. Summary of the Invention

[0005] Based on this, it is necessary to provide a passive heat removal system that does not rely on active components to address the problems of complex system design, increased cost, and low reliability caused by the use of active components for circulation in nuclear reactors in related technologies, thereby improving reactor safety, simplifying system design schemes, and reducing the overall system cost of nuclear reactors.

[0006] A nuclear reactor comprising:

[0007] a reactor vessel, wherein a liquid coolant is disposed in the reactor vessel, and a portion of the reactor vessel above the liquid coolant forms an air cavity;

[0008] a heat exchange device disposed in the reactor vessel and below the liquid level of the liquid coolant, the heat exchange device comprising an inner wall and an outer wall, the inner wall surrounding and forming a first cavity for accommodating a core, and the outer wall and the inner wall jointly defining a sealed second cavity;

[0009] a driving device, the driving device being disposed in the reactor vessel and positioned above the liquid coolant level, comprising a suction end and a re-injection end, the suction end being in communication with the air cavity, the re-injection end extending into the first cavity and being disposed close to the core;

[0010] A water supply device is connected to the second cavity and is used to provide circulating cold source water required by the heat exchange device.

[0011] In one embodiment, a plurality of heat dissipation fins are provided on opposite side walls of the second cavity. The plurality of heat dissipation fins are circumferentially spaced along the side walls of the second cavity, and the heat dissipation fins extend vertically along the side walls of the second cavity.

[0012] In one embodiment, a plurality of support members are provided inside the reactor vessel, including a first support member provided on the inner side wall of the reactor vessel and a second support member provided on the inner bottom of the reactor vessel, and the heat exchange device is suspended in the reactor vessel in conjunction with the support members.

[0013] In one embodiment, the liquid coolant is a molten metal coolant, and the air cavity is filled with an inert gas.

[0014] In one embodiment, the driving device includes a gas compression pump, one end of which is provided with a suction pipe connected to the air cavity, and the other end is provided with a re-injection pipe, an annular injection pipe is provided near the core, and a plurality of upward nozzles are provided along the circumference of the annular injection pipe, one end of the re-injection pipe is connected to the gas compression pump, and the other end is connected to the annular injection pipe.

[0015] In one embodiment, the reactor vessel includes a vessel body and a vessel cover, the upper end surface of the vessel body is provided with an opening, the opening is provided with an adaptable vessel cover, a steam generator is provided on the inner side wall of the vessel body, and the heat exchange device is provided on the steam generator so that the outer wall surface is close to the steam generator.

[0016] In one embodiment, the heat exchange device further includes a coolant pipe, one end of the coolant pipe is connected to the water supply device, and the other end is connected to the second cavity, the coolant pipe includes an outlet pipe and an inlet pipe, and the outlet pipe is arranged above the inlet pipe.

[0017] In one embodiment, the core includes a fuel rod bundle and a control rod assembly. By controlling the insertion depth of the control rod assembly, the nuclear power of the fuel rods to generate nuclear reactions is controlled. The outside of the core is wrapped with a neutron reflection layer.

[0018] In one embodiment, the water supply device is configured as a pool-type water supply device, comprising a pit for accommodating the reactor vessel, a pipe through-hole being provided on the reactor vessel, and the outlet pipe and the inlet pipe are both connected to the pit through the pipe through-hole.

[0019] In one embodiment, the water supply device is configured as a tubular water supply device, including an inlet main pipe, an outlet main pipe and a cold source water tank. Multiple outlet pipes and multiple inlet pipes are circumferentially arranged along the outer wall of the heat exchange device. Multiple inlet pipes merge to form the inlet main pipe, and multiple outlet pipes merge to form the outlet main pipe. The inlet main pipe and the outlet main pipe are respectively used to connect the cold source water tank with the second cavity. A second isolation valve is provided on the outlet main pipe, and a third isolation valve is provided on the inlet main pipe. The height of the cold source water tank is higher than the reactor vessel, and an exhaust window communicating with the outside is provided on the upper end face of the cold source water tank.

[0020] The nuclear reactor comprises a reactor vessel, a heat exchange device, a drive device, and a water supply device. Liquid coolant is disposed within the reactor vessel, with the portion above the liquid coolant forming an air cavity. The heat exchange device is disposed below the liquid coolant level in the reactor vessel. The heat exchange device's inner wall defines a first cavity for accommodating the reactor core, and the outer and inner walls together define a sealed second cavity in communication with the water supply device. During normal operation of the nuclear power plant, the reactor core has a high power. Gas is extracted from the air cavity via the drive device's suction port and then injected into the liquid coolant at the top of the core via the injection port. This injected gas causes the average density of the liquid coolant above the top of the core to be lower than the average density of the coolant near the steam generator at the same height, thereby generating a gravity difference that drives the liquid coolant to circulate within the reactor vessel, transferring heat generated by the core. In the event of an accident in the nuclear power plant, the drive device ceases operation, and the core's heat removal system ceases to function properly. Circulating cold water in the water supply device circulates through the second cavity, continuously exchanging heat with the core to remove excess heat from the core. This reactor does not require a large main pump, which reduces the complexity and cost of the entire system and avoids the problem of low system reliability caused by failure of the heat removal system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A front cross-sectional view of the nuclear reactor (excluding the water supply device);

[0022] Figure 2 is a schematic diagram of an internal cross-section of a reactor vessel of a nuclear reactor;

[0023] Figure 3 It is a front cross-sectional view of a heat exchange device of a nuclear reactor;

[0024] Figure 4 It is a top-down cross-sectional view of a heat exchange device of a nuclear reactor;

[0025] Figure 5 A schematic diagram of the structure of a pool-type water supply device for a nuclear reactor;

[0026] Figure 6 Schematic diagram of the structure of a tubular water supply device for a nuclear reactor. DETAILED DESCRIPTION

[0027] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0030] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0031] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0033] In related technologies, nuclear reactors often use loop heat exchangers to generate natural circulation power. The amount of power generated depends on the relative height difference between the heat source and the cooling source. If the height difference is too small, natural circulation cannot be achieved. Using a loop heat exchanger requires the installation of a heat exchanger as a heat transfer interface. In small integrated reactors, there is no spare space for a heat exchanger. Furthermore, loop heat exchangers use thin tubes with small diameters and thin walls, which are prone to rupture under high temperature and pressure conditions, making them less reliable.

[0034] See Figure 1 and Figure 2An embodiment of the present invention provides a nuclear reactor, including a reactor vessel 100, a heat exchange device 200, a drive device 300, and a water supply device 400. The reactor vessel 100 includes a liquid coolant, and a portion of the reactor vessel 100 located above the liquid coolant forms an air cavity 150. The heat exchange device 200 is disposed in the reactor vessel 100 and is located below the liquid level of the liquid coolant. The heat exchange device 200 includes an inner wall 210 and an outer wall 220. The inner wall 210 is provided with a liquid coolant. 10 surrounds a first cavity 240 for accommodating the core 500, and the outer wall 220 and the inner wall 210 jointly define a sealed second cavity 250. A drive device 300 is arranged in the reactor vessel 100 and is located above the liquid level of the liquid coolant. The drive device 300 includes a suction end and a re-injection end. The suction end is connected to the air cavity 150, and the re-injection end extends into the first cavity 240 and is arranged close to the core 500. A water supply device 400 is connected to the second cavity 250 and is used to provide circulating cold water required by the heat exchange device 200.

[0035] The nuclear reactor includes a reactor vessel 100, a heat exchange device 200, a drive device 300 and a water supply device 400, wherein liquid coolant is provided in the reactor vessel 100, and the portion above the liquid coolant forms an air cavity 150. The heat exchange device 200 is provided below the liquid level of the liquid coolant in the reactor vessel 100. The first cavity 240 surrounded by the inner wall 210 of the heat exchange device 200 is used to accommodate the core 500, and the outer wall 220 and the inner wall 210 jointly define a sealed second cavity 250 that is connected to the water supply device 400.

[0036] When the nuclear power plant is operating normally, the power of the reactor core 500 is relatively high. The suction end of the driving device 300 extracts gas from the air cavity 150 and then injects it into the liquid coolant at the top of the core 500 through the reinjection end. The injected gas makes the average density of the liquid coolant above the top of the core 500 lower than the average density of the coolant near the steam generator 140 at the same height, thereby generating a gravity difference, driving the liquid coolant to circulate inside the reactor vessel 100 to form a circulation route from the outlet above the first cavity core 500-upper chamber 160-down annular cavity 171-lower chamber 170-core 500 inlet-core 500-core 500-outlet above the core 500. The liquid coolant flows from top to bottom in the reactor vessel 100 to transfer the heat generated by the core 500 to the steam generator 140 arranged in the down annular cavity 171. In the event of an accident at the nuclear power plant, the drive unit 300 ceases operation, and the heat removal system in the core 500 ceases to function properly. The circulating cold water in the water supply unit 400 circulates through the second cavity 250, continuously exchanging heat with the core 500 and dissipating excess heat from the core 500. This reactor eliminates the need for a large main pump, reducing overall system complexity and cost, and avoiding the potential for reduced system reliability due to heat removal system failure.

[0037] Furthermore, the outer wall 220 is disposed outside the inner wall 210. The heat exchange device 200 also includes a connecting wall 230 defining a second cavity 250. The connecting wall 230 is disposed between the outer wall 220 and the two end surfaces of the inner wall, forming a sealed annular cavity. Through contact between the inner and outer walls 220 of the heat exchange device 200 and the coolant in the core 500 of the first cavity 240, heat from the coolant can be transferred via heat conduction to the inner wall of the second cavity 250 and to the heat dissipation fins 260 welded to the inner wall of the second cavity 250. The heat exchange device 200 of this embodiment is made of stainless steel and is used to dissipate residual heat during the shutdown state of the nuclear reactor. It also separates the core 500 and the outer side into two distinct circulation channels, eliminating the need for a separate core 500 hanging basket for the nuclear reactor, saving equipment cost and space.

[0038] See Figure 3 and Figure 4 In some embodiments, a plurality of heat dissipation fins 260 are disposed on opposite side walls of the second cavity 250. The plurality of heat dissipation fins 260 are circumferentially spaced along the side walls of the second cavity 250 and extend vertically along the side walls of the second cavity 250. In this embodiment, the heat dissipation fins 260 are thin-sheet structures to increase the heat exchange area in contact with the cold water source and improve heat exchange efficiency.

[0039] In some embodiments, multiple support members (not shown in the figure) are arranged inside the reactor vessel 100, including a first support member arranged on the inner wall of the reactor vessel 100 and a second support member arranged on the bottom of the reactor vessel 100. The heat exchange device 200 is suspended in the reactor vessel 100 in conjunction with the support members to achieve better heat exchange effect.

[0040] Specifically, the heat exchange device 200 is suspended inside the reactor vessel 100 by a plurality of supports. At this time, an upper chamber 160 is formed above the core 500 in the reactor vessel 100 and below the liquid coolant level, and a lower chamber 170 is formed below the core 500 in the reactor vessel 100. The lower chamber 170 also includes a descending annular cavity 171 between the outer wall 220 of the heat exchange device 200 and the inner wall of the reactor vessel 100.

[0041] In some embodiments, the liquid coolant is a molten metal coolant, and the air cavity 150 is filled with an inert gas. Specifically, the molten metal coolant of a nuclear reactor can be a variety of different types of liquids, including liquid sodium, lead, lead-bismuth alloy, etc. Since liquid metal coolant has a high density and good thermal conductivity, the use of molten metal coolant in this nuclear reactor can significantly increase the safety performance of the reactor. In addition, the air cavity 150 at the liquid level of the molten metal coolant is filled with an inert gas to control the pressure of the molten metal coolant and maintain it within a certain safety range. In addition, the use of molten metal as a coolant in the first circuit does not require too much high head difference between the cold and hot sources, which can save layout space.

[0042] See Figure 5 and Figure 6 In one embodiment, the driving device 300 includes a gas compression pump 310, one end of the gas compression pump 310 is provided with a suction pipe 320 connected to the air cavity 150, and the other end is provided with a reinjection pipe 330, an annular injection pipe 340 is provided near the core 500, and a plurality of upward nozzles 341 are provided along the circumference of the annular injection pipe 340, one end of the reinjection pipe 330 is connected to the gas compression pump 310, and the other end is connected to the annular injection pipe 340.

[0043] Furthermore, in this embodiment, to prevent the loss of liquid coolant within the nuclear reactor when the suction pipe 320 and the return pipe 330 rupture, the gas compression pump 310 is positioned above the liquid coolant level within the reactor vessel 100. That is, both the suction pipe 320 and the return pipe 330 are positioned above the internal coolant level within the reactor vessel 100. The return pipe 330 comprises a first tube 331 that penetrates the reactor vessel 100 and a second tube 332 that curves and extends downward along the inner wall 210 of the heat exchange device 200. The second tube 332 is connected to the annular gas injection pipe 340. Multiple nozzles 341 spaced apart within the annular gas injection pipe 340 enable more uniform gas discharge. Using the simpler gas compression pump 310 in place of the main pump, adjusting the flow rate of the gas compression pump 310 changes the gravity difference, thereby varying the coolant flow rate within the core 500. This simplifies the flow path throughout the nuclear reactor, reduces resistance, and improves natural circulation capacity.

[0044] See Figure 1 In one embodiment, the reactor vessel 100 includes a vessel body 110 and a vessel cover 120. An opening is provided on the upper end surface of the vessel body 110, and an adaptable vessel cover 120 is provided on the opening. A steam generator 140 is provided on the inner side wall of the vessel body 110, and a heat exchange device 200 is provided on the steam generator 140 so that the outer wall surface 220 is close to the steam generator 140.

[0045] In this embodiment, the vessel body 110 is cylindrical and vertically upright, primarily housing the nuclear reactor core 500 and coolant. It is constructed of stainless steel. The steam generator 140 is positioned between the outer wall 220 of the heat exchanger 200 and the inner wall of the vessel body 110, i.e., above the descending annular cavity 171. It is positioned as high as possible, higher than the core 500.

[0046] It should be clarified that steam generator 140 is part of the normal heat removal system within the nuclear reactor. During normal operation, steam generator 140 directly exchanges heat with the liquid coolant within reactor vessel 100, generating high-temperature superheated steam that drives the turbine and, in turn, the generator. In this situation, the isolation valve within water supply device 400 remains closed. Following an accident at a nuclear power plant, steam generator 140, part of the normal heat removal system, becomes inoperable. In this situation, the second cavity 250 within heat exchange device 200, in conjunction with water supply device 400, is used to perform heat exchange to remove excess heat from the core 500.

[0047] Specifically, the steam generator 140 is composed of a spiral heat exchange tube bundle. The inside of the tube bundle is provided with cold water by the main water supply system of the nuclear reactor, and the outside of the tube bundle is immersed in the coolant of the nuclear reactor. The spiral heat exchange tube is made of high-strength steel alloy material, which can transfer the heat in the nuclear reactor coolant to the inner wall of the heat exchange tube, gradually heating the cold water flowing inside it. After absorbing heat, the cold water gradually vaporizes and becomes high-temperature and high-pressure superheated steam. It is discharged from the end of the heat exchange tube and enters the main steam system of the nuclear reactor, driving the turbine, and then driving the generator to generate power.

[0048] In one embodiment, the heat exchange device 200 further includes a coolant pipe 270, one end of the coolant pipe 270 is connected to the water supply device 400, and the other end is connected to the second cavity 250, and the coolant pipe 270 includes an outlet pipe 271 and an inlet pipe 272, and the outlet pipe 271 is arranged above the inlet pipe 272.

[0049] The outlet pipe 271 and the inlet pipe 272 can be arranged at various angles in the radial cross-section of the reactor vessel 100. The angles and number of arrangement can be set according to actual needs. In this embodiment, the outlet pipe 271 is arranged above the inlet pipe 272. Specifically, to ensure the circulation effect of the second cavity 250 in the heat exchange device 200, the outlet pipe 271 is arranged at the end of the heat exchange device 200 away from the core 500, and the inlet pipe 272 is arranged at the end of the heat exchange device 200 closer to the bottom of the core 500, so that the cold source water in the second cavity 250 can fully achieve heat exchange.

[0050] After the outlet pipe 271 and the inlet pipe 272 penetrate the wall of the reactor vessel 100, one end is connected to the second cavity 250 of the heat exchange device 200, and the other end is connected to the water supply device 400 for providing circulating cold water. When the cold water does not enter the heat exchange device 200, the second cavity 250 of the heat exchange device 200 is filled with non-condensable inert gas and will not exchange heat with the liquid coolant in the nuclear reactor. When the cold water in the water supply device 400 enters the inlet pipe 272 due to gravity and enters the bottom of the heat exchange device 200, before the water level rises to the height of the pipe mouth of the outlet pipe 271, the cold water contacts the two side walls of the second cavity 250 and the heat dissipation fins 260 for heat exchange. After being heated by the heat of the core 500, the cold water will be heated and evaporated, and the generated water vapor will be discharged from the outlet pipe 271.

[0051] In one embodiment, the core 500 includes a fuel rod bundle and a control rod assembly. By controlling the insertion depth of the control rod assembly, the nuclear power of the fuel rods to generate nuclear reactions is controlled. The outer side of the core 500 is wrapped with a neutron reflector 510.

[0052] Specifically, because the heat exchange device 200 is immersed in the liquid coolant of the reactor vessel 100, its outer wall 220 exchanges heat with the coolant in the downcomer annulus 171, while portions of its inner wall 210 exchange heat with the neutron reflector 510 and coolant in the upper chamber 160. Even under conditions where the natural circulation flow rate of the core 500 is low, decay heat from the core 500 can still be continuously removed through the inner wall 210 of the heat exchange device 200. Thus, heat generated by nuclear reactions in the core 500 is transferred to the coolant flowing through the core 500 through heat exchange. By surrounding the core 500 with a neutron reflector 510 that reflects neutrons back into the core 500, the loss of fission neutrons to the surrounding environment is reduced, thereby increasing the burnup depth of the nuclear reactor.

[0053] It should be noted that when the nuclear reactor is operating normally, the emergency residual heat removal function of the heat exchange device 200 is not enabled, the isolation valve is closed, and the second cavity 250 of the heat exchange device 200 is filled with non-condensable inert gas, which does not exchange heat with the coolant in the reactor core 500. If a primary or secondary side accident occurs in the nuclear reactor, the reactor is shut down, and an automatic signal triggers the activation of the isolation valve, commencing the emergency residual heat removal operation.

[0054] See Figure 5 In one embodiment, the water supply device 400 is configured as a pool-type water supply device 400, including a pit 410 for accommodating the reactor vessel 100, and a pipe through hole 130 is provided on the reactor vessel 100, and the outlet pipe 271 and the inlet pipe 272 are both connected to the pit 140 through the pipe through hole 130.

[0055] In this embodiment, when the nuclear reactor adopts a pool-type water supply device 400, the entire reactor vessel 100 is arranged in a sunken pit 410, and the outlet pipe 271 and the inlet pipe 272 of the heat exchange device 200 are directly connected to the internal space of the pit 140 through the pipe through hole 130. There is no need for an additional isolation valve to be connected between the two, which simplifies the structure of the reactor vessel 100. The water supply device 400 can directly inject cold source water into the pit 410.

[0056] Furthermore, the water supply device may include a cold source water tank 420 and a drain pipe 430. The drain pipe 430 is provided to connect the cold source water tank 420 and the pit 410. A first isolation valve 440 for controlling the on-off is provided on the drain pipe 430. The height of the cold source water tank 420 is higher than the pit 410, and an exhaust window 450 connected to the outside is provided on the upper end surface of the cold source water tank 420.

[0057] To accommodate the height difference, a cooling water tank 420 is positioned above the reactor vessel 100 and the pit 410. A first isolation valve 440 is installed on the drain pipe 430 to control the flow of cooling water. An exhaust port 450 at the top of the cooling water tank 420 draws air from outside the tank into the tank to balance the pressure, ensuring that cooling water within the tank can be smoothly injected into the pit 410. To quickly raise the water level in the pit 410 to submerge the inlet pipe 272, the diameter of the drain pipe 430 can be appropriately increased, while simultaneously reducing the volume of the pit 410 below the level of the outlet pipe 271.

[0058] The working process of nuclear reactor waste heat removal under this scheme is as follows: when the waste heat of the core 500 cannot be discharged normally, the emergency waste heat signal is issued to trigger the opening of the first isolation valve 440. The cooling water in the cold source water tank 420 is injected into the pit 410 through the drain pipe 430 under the action of gravity. When the water level in the pit 410 rises to submerge the inlet pipe 272, the cooling water begins to enter the second cavity 250 of the heat exchange device 200, thereby contacting and exchanging heat with the heat dissipation fins 260 in the second cavity 250 and the wall surface of the second cavity 250. Part of the cooling water in the second cavity 250 will be heated and evaporated, and the generated water vapor will be discharged from the outlet pipe 271, forming a natural circulation flow path of cooling water from the cold source water tank 420-pit 410-inlet pipe 272-second cavity 250 of the heat exchange device-outlet pipe 271-pit 410, continuously removing the decay heat from the nuclear reactor.

[0059] See Figure 6 In some embodiments, the water supply device 400 is configured as a tubular water supply device 400, including an inlet main pipe 460, an outlet main pipe 470 and a cold source water tank 420. Multiple outlet pipes 271 and multiple inlet pipes 272 are circumferentially arranged along the outer wall of the heat exchange device 200. Multiple inlet pipes 272 merge to form the inlet main pipe 460, and multiple outlet pipes 271 merge to form the outlet main pipe 470. The inlet main pipe 460 and the outlet main pipe 470 are respectively used to connect the cold source water tank 420 with the second cavity 250. A second isolation valve 480 is provided on the outlet main pipe 470, and a third isolation valve 490 is provided on the inlet main pipe 460. The height of the cold source water tank 420 is higher than the reactor vessel 100, and an exhaust window 450 communicating with the outside is provided on the upper end surface of the cold source water tank 420.

[0060] In this embodiment, when the nuclear reactor adopts a tubular water supply device 400, the cold source water tank 420 is arranged at a position as high as possible above the reactor vessel 100, and the outlet main pipe 470 and the inlet main pipe are respectively connected to the bottom of the cold source water tank 420, thereby forming a circulation heat exchange loop of cold source water tank 420-inlet main pipe 460-inlet pipe 272-second cavity 250 of heat exchange device 200-outlet pipe 271-outlet main pipe 470-cold source water tank 420.

[0061] The working process of nuclear reactor waste heat discharge under this scheme is as follows: when the waste heat of the core 500 cannot be discharged normally, the emergency waste heat signal is sent to trigger the second isolation valve 480 and the third isolation valve 490 to open at the same time, and the cooling water in the cold source water tank 420 is injected into the inlet main pipe 460 under the action of gravity, and then enters the inlet pipe 272 of the heat exchange device 200, pushing away the non-condensable gas originally in the second heat exchange cavity 250, and the non-condensable gas enters the outlet pipe 271, then reaches the outlet main pipe, and finally enters the cold source water tank 420. After the heat exchanger 200 is filled with cooling water, it exchanges heat with the fins 260 and the walls of the second cavity 250, gradually increasing its temperature and decreasing its density. This causes the gravity head of the inlet main pipe to be greater than the gravity head of the outlet main pipe, creating a gravity differential driving force. This in turn forms a circulating heat exchange loop from the cold source water tank 420 to the inlet main pipe, then to the inlet pipe 272, then to the heat exchanger 200, then to the outlet pipe 271, then to the outlet main pipe, then to the cold source water tank 420, continuously removing decay heat from the reactor. Under this scheme, the water temperature in the cold source water tank 420 gradually rises, and the steam generated by boiling is discharged to the outside environment through the exhaust window 450 at the top of the water tank.

[0062] The cold water tank 420 in the two aforementioned solutions can be configured in various irregular shapes, such as square or cylindrical, depending on the characteristics of the nuclear reactor building. Specifically, it can be constructed from stainless steel or concrete with a stainless steel lining. Cold water tank 420 contains a large amount of deionized water, and the initial water volume can be set based on the reactor's power requirements.

[0063] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A nuclear reactor, characterized in that: include: A reactor vessel (100), wherein a liquid coolant is provided in the reactor vessel (100), and a portion of the reactor vessel (100) located above the liquid coolant forms an air cavity (150); A heat exchange device (200), the heat exchange device (200) being arranged in the reactor vessel (100) and located below the liquid level of the liquid coolant, the heat exchange device (200) comprising an inner wall surface (210) and an outer wall surface (220), the inner wall surface (210) surrounding and forming a first cavity (240) for accommodating a core (500), and the outer wall surface (220) and the inner wall surface (210) jointly defining a sealed second cavity (250); A driving device (300) is provided in the reactor vessel (100) and is positioned higher than the liquid level of the liquid coolant, and includes a suction end and a re-injection end, wherein the suction end is communicated with the air cavity (150), and the re-injection end extends into the first cavity (240) and is arranged close to the core (500); the driving device (300) includes a gas compression pump (310), one end of the gas compression pump (310) is provided with a suction pipe (320) communicated with the air cavity (150), and the other end is provided with a re-injection pipe (330), and an annular injection pipe (340) is provided close to the core (500), and a gas injection pipe (340) is provided along the annular injection pipe (340) A plurality of upward-facing nozzles (341) are arranged in a circumferential direction; one end of the re-injection pipe (330) is connected to the gas compression pump (310), and the other end is connected to the annular injection pipe (340); the positions of the two pipelines, the suction pipe (320) and the re-injection pipe (330), penetrating the wall surface of the reactor vessel (100) are both higher than the liquid level of the internal coolant; the re-injection pipe (330) comprises a first pipe body (331) penetrating the reactor vessel (100) and a second pipe body (332) turning downward and extending downward along the inner wall surface (210) of the heat exchange device (200); the second pipe body (332) is connected to the annular injection pipe (340); A water supply device (400), the water supply device (400) is in communication with the second cavity (250) and is used to provide circulating cold source water required by the heat exchange device (200).

2. The nuclear reactor according to claim 1, characterized in that A plurality of heat dissipation fins (260) are provided on the opposite side walls of the second cavity (250), the plurality of heat dissipation fins (260) are circumferentially spaced along the side walls of the second cavity (250), and the heat dissipation fins (260) extend in a vertical direction along the side walls of the second cavity (250).

3. The nuclear reactor according to claim 1, characterized in that A plurality of support members are provided inside the reactor vessel (100), including a first support member provided on the inner side wall of the reactor vessel (100) and a second support member provided on the inner bottom of the reactor vessel (100); the heat exchange device (200) is suspended in the reactor vessel (100) in coordination with the support members.

4. The nuclear reactor according to claim 1, characterized in that The liquid coolant is a molten metal coolant, and the air cavity (150) is filled with an inert gas.

5. The nuclear reactor according to claim 1, characterized in that The reactor vessel (100) comprises a vessel body (110) and a vessel cover (120); an opening is provided on the upper end surface of the vessel body (110); an adapted vessel cover (120) is provided on the opening; a steam generator (140) is provided on the inner side wall of the vessel body (110); and the heat exchange device (200) is provided on the steam generator (140) so that the outer wall surface (220) is close to the steam generator (140).

6. The nuclear reactor according to claim 1, characterized in that The heat exchange device (200) further includes a coolant pipe (270), one end of which is connected to the water supply device (400), and the other end of which is connected to the second cavity (250), and the coolant pipe (270) includes an outlet pipe (271) and an inlet pipe (272), and the outlet pipe (271) is arranged above the inlet pipe (272).

7. The nuclear reactor according to claim 1, characterized in that The core (500) comprises a fuel rod bundle and a control rod assembly. By controlling the insertion depth of the control rod assembly, the nuclear power of the fuel rods to generate nuclear reactions is controlled. The outer side of the core (500) is wrapped with a neutron reflection layer (510).

8. The nuclear reactor according to claim 6, characterized in that The water supply device (400) is configured as a pool-type water supply device (400), comprising a pit (410) for accommodating the reactor vessel (100); a pipe through-hole (130) is provided on the reactor vessel (100); and the outlet pipe (271) and the inlet pipe (272) are both connected to the pit (410) through the pipe through-hole (130).

9. The nuclear reactor according to claim 6, characterized in that The water supply device (400) is configured as a tubular water supply device (400), comprising an inlet main pipe (460), an outlet main pipe (470) and a cold source water tank (420); a plurality of outlet pipes (271) and a plurality of inlet pipes (272) are circumferentially arranged along the outer wall of the heat exchange device (200); a plurality of inlet pipes (272) merge to form the inlet main pipe (460); a plurality of outlet pipes (271) merge to form the outlet main pipe (470). The inlet main pipe (460) and the outlet main pipe (470) are respectively used to connect the cold source water tank (420) with the second cavity (250); the outlet main pipe (470) is provided with a second isolation valve (480); the inlet main pipe (460) is provided with a third isolation valve (490); the height of the cold source water tank (420) is higher than the reactor vessel (100); and the upper end surface of the cold source water tank (420) is provided with an exhaust window (450) communicating with the outside.

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