Natural circulation reactor steam supply system based on loop type thermosiphon and nuclear power station

Abstract

The invention relates to the technical field of nuclear energy application, and provides a natural circulation reactor steam supply system based on a loop type thermosiphon and a nuclear power plant, a natural circulation reactor in the system comprises a reactor pressure vessel, and a reactor core, a control rod driving mechanism and an in-reactor heat exchanger which are arranged in the reactor pressure vessel; the heat pipe circulation loop comprises a steam heat exchange pipe and a backflow heat exchange pipe, one end of the steam heat exchange pipe is connected with a first-stage medium outlet of the in-reactor heat exchanger, the other end of the steam heat exchange pipe is connected with a first-stage medium inlet of the steam generator, and the steam heat exchange pipe is used for conveying a gaseous working medium; one end of the backflow heat exchange tube is connected with a first-stage medium outlet of the steam generator, the other end of the backflow heat exchange tube is connected with a first-stage medium inlet of the in-pile heat exchanger, and the backflow heat exchange tube is used for transmitting a liquid working medium. An additional circulating pump is not needed to push the working medium to flow, the system structure is simplified, equipment fault points are reduced, and the reliability of the system is improved.

Description

Technical Field

[0001] This invention relates to the field of nuclear energy application technology, and in particular to a natural circulation reactor steam supply system and nuclear power plant based on a loop thermosiphon. Background Technology

[0002] Currently, natural circulation reactors employ a forced circulation intermediate loop to achieve heat transfer and isolation between the reactor and the steam generator. The intermediate loop exchanges heat with the reactor coolant system through the main heat exchanger located above the pressure vessel. The intermediate loop is a forced circulation loop equipped with a circulation pump, and the heated coolant enters the steam generator tube side for vaporization.

[0003] Natural circulation reactors are designed to utilize natural circulation principles to circulate the coolant and reduce reliance on external power sources. However, using a forced circulation intermediate loop to achieve heat transfer and isolation between the reactor and the steam generator not only increases system complexity but also reduces reliability. Summary of the Invention

[0004] This invention provides a natural circulation reactor steam supply system and nuclear power plant based on a loop thermosiphon, which solves the above-mentioned technical defects in the prior art. It eliminates the need for an additional circulation pump to drive the flow of the working medium, thereby eliminating the dependence on circulation pumps, simplifying the system structure, reducing equipment failure points, and improving the system reliability.

[0005] A first aspect of the present invention provides a natural circulation reactor steam supply system based on a loop thermosiphon, comprising a natural circulation reactor, a steam generator, and a heat pipe circulation loop; The natural circulation reactor includes a reactor pressure vessel and a reactor core, control rod drive mechanism and in-core heat exchanger located inside the reactor pressure vessel; The heat pipe circulation loop includes a steam heat exchanger tube and a reflux heat exchanger tube. One end of the steam heat exchanger tube is connected to the primary medium outlet of the in-core heat exchanger, and the other end of the steam heat exchanger tube is connected to the primary medium inlet of the steam generator. The steam heat exchanger tube is used to transport gaseous working fluid. One end of the reflux heat exchanger tube is connected to the primary medium outlet of the steam generator, and the other end of the reflux heat exchanger tube is connected to the primary medium inlet of the in-core heat exchanger. The reflux heat exchanger tube is used to transport liquid working fluid.

[0006] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, the heat pipe circulation loop further includes a shut-off valve, which is located on the reflux heat exchanger tube; The shut-off valve is used to regulate the flow rate of the liquid working fluid in the reflux heat exchange tube, and the shut-off valve is also used to prevent the backflow of the liquid working fluid in the reflux heat exchange tube.

[0007] The natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention further includes a controller and a pressure monitoring device. The pressure monitoring device and the shut-off valve are both electrically connected to the controller. The pressure monitoring device is used to monitor the pressure information in the heat pipe circulation loop and feed the pressure information back to the controller. The controller controls the opening degree of the shut-off valve according to the pressure information.

[0008] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, the in-core heat exchanger includes an inlet tube sheet, an outlet tube sheet, and multiple in-core heat exchange tubes; The inlet ends of multiple in-pile heat exchange tubes are inserted into the inlet tube sheet, and the outlet ends of multiple in-pile heat exchange tubes are inserted into the outlet tube sheet. Each in-pile heat exchange tube is the evaporation section of the heat pipe circulation loop. One end of the steam heat exchange tube is connected to the outlet tube sheet, and the other end of the reflux heat exchange tube is connected to the inlet tube sheet.

[0009] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, the steam generator includes a steam pressure vessel and multiple heat exchange tubes. The steam pressure vessel has a heat exchange chamber inside, and the steam pressure vessel is provided with a secondary medium inlet and a secondary medium outlet. Both the secondary medium inlet and the secondary medium outlet are connected to the heat exchange chamber. Multiple heat exchange tubes are arranged horizontally or vertically in the heat exchange cavity.

[0010] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, in the case where multiple heat exchange tubes are horizontally arranged in the heat exchange chamber: The steam pressure vessel internally defines independent evaporation and condensation chambers. The primary medium inlets of the multiple heat exchange tubes are connected to the evaporation chamber, the primary medium outlets of the multiple heat exchange tubes are connected to the condensation chamber, the other end of the steam heat exchange tube is connected to the evaporation chamber, and one end of the reflux heat exchange tube is connected to the condensation chamber. The secondary medium inlet is located below the steam pressure vessel and communicates with the heat exchange chamber; the secondary medium outlet is located above the steam pressure vessel and communicates with the heat exchange chamber.

[0011] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, the steam generator is further provided with a steam-water separator, which is located at the outlet of the secondary medium.

[0012] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, the drain outlet at the bottom of the steam-water separator is connected to a steam trap.

[0013] According to the natural circulation reactor steam supply system based on a loop thermosiphon provided by the present invention, in the case where multiple heat exchange tubes are vertically arranged in the heat exchange chamber: The primary medium inlets of the plurality of heat exchange tubes are connected to the steam heat exchange tubes, and the primary medium outlets of the plurality of heat exchange tubes are connected to the reflux heat exchange tubes. The secondary medium inlet is located below the steam pressure vessel and communicates with the heat exchange chamber; the secondary medium outlet is located above the steam pressure vessel and communicates with the heat exchange chamber.

[0014] A second aspect of the present invention provides a nuclear power plant including the above-described natural circulation reactor steam supply system based on a loop thermosiphon, wherein the working fluid in the heat pipe circulation loop includes, but is not limited to, water and organic working fluid, and the steam generated by the steam generator includes, but is not limited to, water and organic working fluid.

[0015] The present invention provides a natural circulation reactor steam supply system based on a loop thermosiphon. The heat pipe circulation loop includes a steam heat exchanger and a reflux heat exchanger. One end of the steam heat exchanger is connected to the primary medium outlet of the in-core heat exchanger, and the other end is connected to the primary medium inlet of the steam generator. The steam heat exchanger is used to transport gaseous working fluid. One end of the reflux heat exchanger is connected to the primary medium outlet of the steam generator, and the other end is connected to the primary medium inlet of the in-core heat exchanger. The reflux heat exchanger is used to transport liquid working fluid.

[0016] Essentially, a split heat pipe, consisting of heat exchange tubes from the in-core heat exchanger, steam heat exchange tubes, reflux heat exchange tubes, and heat exchange tubes from the steam generator connected in a closed loop, functions as an independent heat transfer element. The circulation of the working medium within the split heat pipe relies on natural phase change driving forces (evaporation and condensation) as well as passive forces such as gravity and capillary action. No additional circulation pump is needed to drive the working medium flow, thus eliminating reliance on a circulation pump, simplifying the system structure, reducing equipment failure points, and improving system reliability. When the reactor core temperature rises, the working medium in the heat pipe's evaporation section evaporates faster, carrying more heat to the condensation section, and the steam generator receives more heat; conversely, when the core temperature decreases, the heat transfer capacity of the heat pipe decreases accordingly. The self-regulating characteristics of the split heat pipe allow the system to automatically adjust the heat transfer rate according to the actual operating conditions of the reactor, maintaining a stable operating state.

[0017] Furthermore, the heat transfer capability of the split heat pipes enables rapid and efficient heat transfer from the reactor core to the steam generator, improving the overall system's heat transfer efficiency. Compared to traditional heat transfer methods relying on forced convection via circulating pumps, the natural circulation heat transfer method of split heat pipes can achieve higher heat transfer at lower temperature differences, thereby improving the system's energy utilization efficiency. Moreover, due to the isothermal characteristics of the split heat pipes, they can operate under more stable temperature conditions, making the heat exchange process in the steam generator more stable and efficient. This helps improve steam quality and pressure, and other operating parameters, thereby enhancing the efficiency and performance of the entire power generation system.

[0018] Meanwhile, the split heat pipe has a compact structure, occupies little space, and its cold and hot sections can be flexibly arranged to adapt to various complex situations.

[0019] The nuclear power plant provided by this invention, because it includes the above-mentioned natural circulation reactor steam supply system based on a loop thermosiphon, possesses all the aforementioned advantages. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of an embodiment of a natural circulation reactor steam supply system based on a loop thermosiphon provided in this invention.

[0022] Figure 2This is a schematic diagram of another embodiment of the natural circulation reactor steam supply system based on a loop thermosiphon provided in this invention.

[0023] Figure label: 1. Natural circulation reactor; 101. Reactor pressure vessel; 102. Reactor core; 103. Control rod drive mechanism; 104. In-core heat exchanger; 2. Heat pipe circulation loop; 201. Evaporation section; 202. Steam heat exchanger tube; 203. Condensation section; 204. Reflux heat exchanger tube; 205. Shut-off valve; 3. Steam generator; 301. Inlet pipe; 302. Outlet pipe; 303. Steam-water separator; 304. Steam pressure vessel; 305. Heat exchange tube. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0026] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0028] Natural circulation reactors are designed to utilize natural circulation principles to achieve coolant circulation, reducing reliance on external power equipment and improving inherent safety. However, using a forced circulation intermediate loop to achieve heat transfer and isolation between the reactor and the steam generator presents the following drawbacks: First, forced circulation requires additional circulating pumps, control equipment, and complex piping systems to drive the circulation of the intermediate medium. This added equipment not only increases the system's hardware cost but also complicates the system structure, making design, construction, and commissioning more difficult. Furthermore, the introduction of forced circulation necessitates precise control of parameters such as the circulating pump's flow rate and pressure to ensure stable heat transfer and meet the requirements of different reactor operating conditions. This necessitates a more complex control system, increasing the difficulty of monitoring and operation during operation and demanding higher levels of technical skill and experience from operators.

[0029] Secondly, as a key component of the forced circulation intermediate loop, a failure of the circulating pump can interrupt the circulation of the intermediate medium, thereby affecting heat transfer between the reactor and the steam generator, and even threatening the safe operation of the reactor. Compared to a natural circulation system, forced circulation adds the circulating pump as a potential source of failure, reducing the reliability of the entire system.

[0030] Furthermore, forced circulation relies on external power to drive the circulation pumps. In extreme situations such as a complete plant power outage, the circulation pumps will malfunction, the forced circulation in the intermediate loop will cease, and heat transfer will be hindered. Although emergency power supplies may be provided, their capacity and duration are limited, posing a safety hazard of insufficient reactor cooling due to loss of power.

[0031] Finally, the operation of the circulating pump consumes electrical energy, increasing the overall energy consumption of the reactor system and reducing energy conversion efficiency. Furthermore, the presence of the intermediate loop adds heat transfer stages, with heat loss occurring at each stage. This reduces the heat transfer efficiency from the reactor to the steam generator, affecting the quantity and quality of steam produced, and consequently reducing the efficiency of the entire power generation system. Therefore, this invention provides a natural circulation reactor steam supply system based on a loop-type thermosiphon.

[0032] Figure 1 This is a schematic diagram of an embodiment of a natural circulation reactor steam supply system based on a loop thermosiphon provided in this invention.

[0033] See Figure 1 This invention provides a natural circulation reactor steam supply system based on a loop thermosiphon, which includes a natural circulation reactor 1, a steam generator 3, and a heat pipe circulation loop 2.

[0034] Natural circulation reactor 1 includes a reactor pressure vessel 101 and a reactor core 102, a control rod drive mechanism 103, and an in-core heat exchanger 104 located inside the reactor pressure vessel 101. The reactor pressure vessel 101, as the core component of the natural circulation reactor 1, houses the reactor core 102, the control rod drive mechanism 103, and the in-core heat exchanger 104. The nuclear fuel (such as uranium dioxide) within the reactor core 102 undergoes a chain fission reaction, releasing enormous amounts of heat energy to heat the surrounding coolant (usually light or heavy water). The reactor pressure vessel 101 needs to withstand high temperatures, high pressures, and strong radiation environments; therefore, it is constructed using high-strength, radiation-resistant special steel.

[0035] The in-core heat exchanger 104 is a heat exchange device for the primary and secondary loops, consisting of tube bundles, tube sheets, and an outer shell. The high-temperature, high-pressure coolant on the primary side flows inside the tube bundle, transferring heat to the water on the secondary side outside the tubes, causing the water to evaporate and generate steam.

[0036] During operation, the nuclear fuel in the reactor core 102 of the natural circulation reactor 1 undergoes a fission reaction, generating a large amount of heat energy and raising the temperature of the coolant near the core. The increased temperature reduces the density of the coolant, causing it to flow upwards under buoyancy and enter the primary side of the in-core heat exchanger 104. In the heat exchanger 104, the high-temperature coolant on the primary side transfers heat to the water on the secondary side through the tube walls. The water on the secondary side absorbs heat, gradually heats up, and boils, producing steam. After releasing heat through the heat exchanger 104, the coolant's temperature decreases, its density increases, and it flows downwards under gravity, returning to the bottom of the reactor pressure vessel 101, where it re-enters the core to be heated, completing one natural circulation cycle. This cycle repeats continuously, transferring the heat generated in the core to the secondary loop, providing a continuous steam supply.

[0037] The heat pipe circulation loop 2 includes a steam heat exchanger 202 and a reflux heat exchanger 204. One end of the steam heat exchanger 202 is connected to the primary medium outlet of the in-core heat exchanger 104, and the other end of the steam heat exchanger 202 is connected to the primary medium inlet of the steam generator 3. The steam heat exchanger 202 is used to transport gaseous working fluid. One end of the reflux heat exchanger 204 is connected to the primary medium outlet of the steam generator 3, and the other end of the reflux heat exchanger 204 is connected to the primary medium inlet of the in-core heat exchanger 104. The reflux heat exchanger 204 is used to transport liquid working fluid.

[0038] Essentially, the heat exchange tubes of the in-core heat exchanger 104, the steam heat exchange tube 202, the reflux heat exchange tube 204, and the heat exchange tube 305 of the steam generator 3 are sequentially and cyclically connected to form a closed loop (i.e., a separate heat pipe), replacing the existing intermediate loop. Since the evaporation section 201 (the heat exchange tubes of the in-core heat exchanger 104) and the condensation section 203 (the heat exchange tube 305 of the steam generator 3) of the separate heat pipe are independently set, they are connected by the steam heat exchange tube 202 and the reflux heat exchange tube 204 to form a closed loop, operating through repeated phase change heat transfer and two-phase flow circulation. In other words, a heat pipe is arranged between the reactor core 102 and the steam generator 3. One end of the heat pipe (evaporation section 201) extends into the region of the reactor core 102, directly absorbing the heat generated by the reactor core 102. The other end of the heat pipe (condensation section 203) extends into the heat exchange tube 305 of the steam generator 3. This arrangement allows the heat from the reactor core 102 to be effectively transferred to the steam generator 3.

[0039] When heat pipe loop 2 is operating, the split heat pipe utilizes the phase change of its internal working medium to achieve efficient heat transfer. In the high-temperature environment of the reactor core 102, the working medium (such as metals like sodium or potassium, or substances like water) in the evaporation section 201 of the split heat pipe absorbs heat and rapidly vaporizes. The steam flows towards the condensation section 203 within the split heat pipe due to the pressure difference. Because the split heat pipe has isothermal characteristics, the temperature change is minimal throughout the transfer process, enabling rapid heat transfer to the more distant condensation section 203. In the steam generator 3, the steam in the condensation section 203 of the split heat pipe condenses into liquid upon cooling, releasing a large amount of latent heat. This heat is transferred to the water in the heat exchange tube 305, causing it to heat up and turn into steam. The condensed working medium flows back to the evaporation section 201 under the influence of gravity or capillary force, completing one cycle and continuously transferring heat from the reactor core 102 to the steam generator 3.

[0040] The separate heat pipe, consisting of the heat exchange tubes of the in-core heat exchanger 104, the steam heat exchange tube 202, the reflux heat exchange tube 204, and the heat exchange tube 305 of the steam generator 3 connected in a closed loop, serves as an independent heat transfer element, structurally achieving physical isolation between the reactor core 102 and the steam generator 3. The pipe wall of the separate heat pipe isolates the high-temperature, radioactive environment on the reactor side from the relatively low-temperature, non-radioactive environment on the steam generator 3 side, preventing radioactive materials from leaking into the steam generator 3.

[0041] It is understood that the natural circulation reactor steam supply system based on a loop thermosiphon provided in this embodiment of the invention includes a heat pipe circulation loop 2 comprising a steam heat exchanger 202 and a reflux heat exchanger 204. One end of the steam heat exchanger 202 is connected to the primary medium outlet of the in-core heat exchanger 104, and the other end of the steam heat exchanger 202 is connected to the primary medium inlet of the steam generator 3. The steam heat exchanger 202 is used to transport gaseous working fluid. One end of the reflux heat exchanger 204 is connected to the primary medium outlet of the steam generator 3, and the other end of the reflux heat exchanger 204 is connected to the primary medium inlet of the in-core heat exchanger 104. The reflux heat exchanger 204 is used to transport liquid working fluid.

[0042] Essentially, the split heat pipe, consisting of the heat exchange tubes of the in-core heat exchanger 104, the steam heat exchange tube 202, the reflux heat exchange tube 204, and the heat exchange tube 305 of the steam generator 3 connected in a closed loop, acts as an independent heat transfer element. The circulation of the working medium within the split heat pipe relies on natural phase change driving forces (evaporation and condensation) as well as passive forces such as gravity and capillary force. No additional circulation pump is needed to drive the flow of the working medium, thus eliminating dependence on a circulation pump, simplifying the system structure, reducing equipment failure points, and improving system reliability. When the reactor core temperature 102 rises, the evaporation rate of the working medium in the heat pipe evaporation section 201 accelerates, and more heat is carried to the condensation section 203, allowing the steam generator 3 to receive more heat; conversely, when the core temperature decreases, the heat transfer capacity of the heat pipe decreases accordingly. The self-regulating characteristics of the split heat pipe enable the system to automatically adjust the heat transfer rate according to the actual operating conditions of the reactor, maintaining a stable operating state.

[0043] Furthermore, the heat transfer capability of the split heat pipes enables rapid and efficient heat transfer from the reactor core 102 to the steam generator 3, improving the overall system's heat transfer efficiency. Compared to traditional heat transfer methods relying on forced convection via circulating pumps, the natural circulation heat transfer method of the split heat pipes can achieve higher heat transfer at lower temperature differences, thereby improving the system's energy utilization efficiency. Moreover, due to the isothermal characteristics of the split heat pipes, they can operate under more stable temperature conditions, making the heat exchange process in the steam generator 3 more stable and efficient. This helps improve the steam quality and pressure, and other operating parameters, thereby enhancing the efficiency and performance of the entire power generation system.

[0044] Meanwhile, the split heat pipe has a compact structure, occupies little space, and its cold and hot sections can be flexibly arranged to adapt to various complex situations.

[0045] Continue reading Figure 1 In some embodiments of the present invention, the heat pipe circulation loop 2 further includes a shut-off valve 205, which is disposed on the return heat exchange tube 204. The shut-off valve 205 is used to regulate the flow rate of the liquid working fluid in the return heat exchange tube 204, and the shut-off valve 205 is also used to prevent the backflow of the liquid working fluid in the return heat exchange tube 204.

[0046] Essentially, during the startup phase of heat pipe circulation loop 2, the shut-off valve 205 can be kept closed, facilitating system inspection and preparation. Once all parts of the system are confirmed to be functioning normally, the shut-off valve 205 is opened, allowing the working medium to begin circulating in heat pipe circulation loop 2, thus ensuring a smooth startup. When the system stops running, closing the shut-off valve 205 quickly cuts off the return path of the working medium, rapidly stopping the circulation and facilitating system maintenance, repair, or emergency handling.

[0047] The shut-off valve 205 can be partially opened or closed to regulate the flow rate of the working medium in the return heat exchanger tube 204. Depending on the system's operating conditions and heat load requirements, adjusting the opening of the shut-off valve 205 changes the circulation volume of the working medium, thereby controlling the heat transfer in the heat pipe circulation loop 2 and ensuring stable and efficient system operation under various conditions.

[0048] In certain special circumstances, such as a sudden power outage or pressure fluctuations caused by equipment failure, backflow of the working medium may occur. The shut-off valve 205 can effectively prevent the backflow of the working medium in the heat exchange tube 204, avoiding damage to components such as the heat tube, evaporator, and condenser, protecting the normal operation of other critical equipment in the system, and extending the service life of the equipment.

[0049] If the return heat exchanger tube 204 or a component connected to it experiences a leak, blockage, or other malfunction, closing the shut-off valve 205 can isolate the faulty part from the rest of the system. This prevents the fault from spreading further and affecting the entire system, and also allows maintenance personnel to repair or replace the faulty component individually without requiring large-scale operations on the entire heat pipe circulation loop 2, thus reducing maintenance costs and complexity.

[0050] In addition, in the event of an emergency such as a fire or earthquake, quickly closing the shut-off valve 205 can immediately stop the operation of the heat pipe circulation loop 2, cut off the heat transfer path, prevent further heat transfer and cause more serious safety accidents, and ensure the safety of personnel and equipment.

[0051] In addition, the shut-off valve 205 can be used in conjunction with the pressure monitoring device in the system to effectively control the pressure in the heat pipe circulation loop 2. When the pressure in the heat pipe circulation loop 2 is too high, the flow rate and velocity of the working medium can be adjusted by appropriately adjusting the opening of the shut-off valve 205, releasing some pressure and maintaining the system pressure within a safe range to ensure the safe and stable operation of the system.

[0052] Continue reading Figure 1 In some embodiments of the present invention, the in-pile heat exchanger 104 includes an inlet tube sheet, an outlet tube sheet, and a plurality of in-pile heat exchange tubes; the inlet ends of the plurality of in-pile heat exchange tubes are all inserted into the inlet tube sheet, the outlet ends of the plurality of in-pile heat exchange tubes are inserted into the outlet tube sheet, and each in-pile heat exchange tube is an evaporation section 201 of the heat pipe circulation loop 2; one end of the steam heat exchange tube 202 is connected to the outlet tube sheet, and the other end of the return heat exchange tube 204 is connected to the inlet tube sheet.

[0053] Continue reading Figure 1In some embodiments of the present invention, the steam generator 3 includes a steam pressure vessel 304 and a plurality of heat exchange tubes 305. The interior of the steam pressure vessel 304 restricts the heat exchange chamber. The steam pressure vessel 304 is provided with a secondary medium inlet and a secondary medium outlet, both of which are connected to the heat exchange chamber. The plurality of heat exchange tubes 305 are arranged horizontally or vertically in the heat exchange chamber.

[0054] Continue reading Figure 1 In some embodiments of the present invention, when multiple heat exchange tubes 305 are horizontally arranged in the heat exchange chamber (equivalent to using a natural circulation steam generator 3): The steam pressure vessel 304 internally defines independent evaporation and condensation chambers. The primary medium inlets of multiple heat exchange tubes 305 are connected to the evaporation chamber, and the primary medium outlets of multiple heat exchange tubes 305 are connected to the condensation chamber. The other end of the steam heat exchange tube 202 is connected to the evaporation chamber, and one end of the return heat exchange tube 204 is connected to the condensation chamber. The secondary medium inlet is located below the steam pressure vessel 304 and is connected to the heat exchange chamber. The secondary medium outlet is located above the steam pressure vessel 304 and is connected to the heat exchange chamber.

[0055] The steam pressure vessel 304 can be made of high-strength alloy steel, capable of withstanding high-temperature and high-pressure environments. The steam pressure vessel 304 is cylindrical in shape with hemispherical end caps to ensure structural strength. Inside the steam pressure vessel 304, a partition separates the evaporation chamber and the condensation chamber. The partition, made of high-temperature and corrosion-resistant metal, is welded to the inner wall of the steam pressure vessel 304 to ensure a tight seal between the two chambers. The evaporation chamber, located in the upper part of the vessel, has a larger space to accommodate the evaporation of the working medium; the condensation chamber, located in the lower part of the vessel, has a relatively smaller space for the condensation of the working medium vapor.

[0056] Multiple heat exchange tubes 305 are horizontally arranged within the heat exchange chamber. The heat exchange tubes 305 are made of stainless steel, possessing excellent thermal conductivity and corrosion resistance. The heat exchange tubes 305 ensure a suitable flow velocity and volume for the primary medium (the hot fluid drawn from the natural circulation reactor 1) within the tubes. One end of each heat exchange tube 305 is the primary medium inlet, connected to the evaporation chamber. The other end of each heat exchange tube 305 is the primary medium outlet, connected to the condensation chamber.

[0057] After the secondary medium absorbs heat and turns into steam, it is discharged through the secondary medium outlet, providing steam output for the system. The secondary medium inlet is used to supply the secondary medium to the heat exchange chamber to continuously participate in the heat exchange process.

[0058] The secondary medium inlet can be connected to inlet pipe 301, on which a flow regulating valve and a filter can be installed. The flow regulating valve precisely controls the flow rate of the secondary medium entering the heat exchange chamber according to the system's heat load requirements; the filter is used to filter impurities in the water to prevent impurities from entering the interior of the heat exchange chamber and affecting heat exchange efficiency and equipment life.

[0059] An outlet pipe 302 can be connected to the secondary medium outlet. This outlet pipe 302 connects to the steam distribution system, delivering the generated steam to the various required production stages. Pressure and temperature sensors are installed on the outlet pipe 302 to monitor the steam pressure and temperature in real time, enabling precise system control.

[0060] In the natural circulation reactor steam supply system based on a loop thermosiphon provided in this embodiment of the invention, during operation, the high-temperature waste heat fluid (primary medium) of the natural circulation reactor 1 flows into the heat exchange tube 305 on the evaporation chamber side through the steam heat exchange tube 202 from the primary medium inlet. During this process, the high-temperature waste heat fluid transfers heat to the secondary medium (such as water) in the heat exchange tube 305, and the temperature of the primary medium gradually decreases. After absorbing heat, the secondary medium in the heat exchange chamber increases in temperature and begins to evaporate. As steam is continuously generated, once the steam in the heat exchange chamber reaches a certain pressure, it is transported to the production stage through the outlet pipe 302.

[0061] The primary medium, which has already released some heat, continues to transfer the remaining heat to the surrounding steam, causing the steam to condense into liquid water. The condensate flows back to the in-core heat exchanger 104 of the natural circulation reactor 1 through the return heat exchange tube 204, forming a continuous cycle.

[0062] Continue reading Figure 1 In some embodiments of the present invention, the steam generator 3 is further provided with a steam-water separator 303, which is located at the outlet of the secondary medium.

[0063] Essentially, a steam-water separator 303 is installed at the top of the steam generator 3, near the outlet of the secondary medium. This location is a critical node in the steam rising channel, enabling effective separation of the steam-water mixture rising from the heat exchange tube bundle area.

[0064] The steam-water separator 303 can employ a composite structure combining high-efficiency cyclone separation and corrugated plates. The cyclone separator consists of multiple upright cyclone tubes, evenly distributed across the cross-section of the steam generator 3. The inlet of each cyclone tube is connected to the steam rising channel, and the steam-water mixture enters the cyclone tube tangentially at a high velocity. Under centrifugal force, heavier water droplets are thrown against the tube wall, flowing downwards along the wall and exiting through a dedicated drain outlet into the water space of the steam generator 3. The lighter steam forms an upward airflow at the center of the cyclone tube and flows out from the outlet at the top of the cyclone tube. Above the cyclone separator, a multi-layer corrugated plate assembly is installed. The steam, after cyclone separation, carries a small amount of fine water droplets and continues to flow upwards into the corrugated plate separator. The special shape of the corrugated plates causes the steam to flow in a tortuous manner. Under the action of inertial and adhesive forces, water droplets adhere to the surface of the corrugated plates, condensing into larger droplets that slide down the corrugated plates and eventually return to the water space.

[0065] Furthermore, a drain valve is connected to the drain outlet at the bottom of the steam-water separator 303.

[0066] Figure 2 This is a schematic diagram of another embodiment of the natural circulation reactor steam supply system based on a loop thermosiphon provided in this invention.

[0067] See Figure 2 In some embodiments of the present invention, when multiple heat exchange tubes 305 are vertically arranged in the heat exchange chamber (equivalent to using a direct-flow steam generator 3): The primary medium inlets of multiple heat exchange tubes 305 are connected to the steam heat exchange tube 202, and the primary medium outlets of multiple heat exchange tubes 305 are connected to the reflux heat exchange tube 204; the secondary medium inlet is located below the steam pressure vessel 304 and communicates with the heat exchange chamber; the secondary medium outlet is located above the steam pressure vessel 304 and communicates with the heat exchange chamber.

[0068] In addition to the steam generator 3 mentioned above, the natural circulation reactor steam supply system based on a loop thermosiphon provided in this embodiment of the invention can also use other steam generators 3.

[0069] It should be noted that the working fluid in the heat pipe circulation loop 2 includes, but is not limited to, water and organic working fluids, and the steam generated by the steam generator 3 includes, but is not limited to, water and organic working fluids.

[0070] The present invention also provides a nuclear power plant including the aforementioned natural circulation reactor steam supply system based on a loop thermosiphon. Because it includes the aforementioned natural circulation reactor steam supply system based on a loop thermosiphon, it possesses all the advantages described above.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A natural circulation reactor steam supply system based on a loop thermosiphon, characterized in that, Includes a natural circulation reactor, a steam generator, and a heat pipe circulation loop; The natural circulation reactor includes a reactor pressure vessel and a reactor core, control rod drive mechanism and in-core heat exchanger located inside the reactor pressure vessel; The heat pipe circulation loop includes a steam heat exchanger tube and a reflux heat exchanger tube. One end of the steam heat exchanger tube is connected to the primary medium outlet of the in-core heat exchanger, and the other end of the steam heat exchanger tube is connected to the primary medium inlet of the steam generator. The steam heat exchanger tube is used to transport gaseous working fluid. One end of the reflux heat exchanger tube is connected to the primary medium outlet of the steam generator, and the other end of the reflux heat exchanger tube is connected to the primary medium inlet of the in-core heat exchanger. The reflux heat exchanger tube is used to transport liquid working fluid.

2. The natural circulation reactor steam supply system based on a loop thermosiphon as described in claim 1, characterized in that, The heat pipe circulation loop also includes a shut-off valve, which is located on the return heat exchanger tube. The shut-off valve is used to regulate the flow rate of the liquid working fluid in the reflux heat exchange tube, and the shut-off valve is also used to prevent the backflow of the liquid working fluid in the reflux heat exchange tube.

3. The natural circulation reactor steam supply system based on a loop thermosiphon according to claim 2, characterized in that, It also includes a controller and a pressure monitoring device. Both the pressure monitoring device and the shut-off valve are electrically connected to the controller. The pressure monitoring device is used to monitor the pressure information in the heat pipe circulation loop and feed the pressure information back to the controller. The controller controls the opening degree of the shut-off valve according to the pressure information.

4. The natural circulation reactor steam supply system based on a loop thermosiphon according to claim 1, characterized in that, The in-core heat exchanger includes an inlet tube sheet, an outlet tube sheet, and multiple in-core heat exchange tubes. The inlet ends of multiple in-pile heat exchange tubes are inserted into the inlet tube sheet, and the outlet ends of multiple in-pile heat exchange tubes are inserted into the outlet tube sheet. Each in-pile heat exchange tube is the evaporation section of the heat pipe circulation loop. One end of the steam heat exchange tube is connected to the outlet tube sheet, and the other end of the reflux heat exchange tube is connected to the inlet tube sheet.

5. The natural circulation reactor steam supply system based on a loop thermosiphon according to any one of claims 1 to 4, characterized in that, The steam generator includes a steam pressure vessel and multiple heat exchange tubes. The steam pressure vessel has a heat exchange chamber inside. The steam pressure vessel is provided with a secondary medium inlet and a secondary medium outlet. Both the secondary medium inlet and the secondary medium outlet are connected to the heat exchange chamber. Multiple heat exchange tubes are arranged horizontally or vertically in the heat exchange cavity.

6. The natural circulation reactor steam supply system based on a loop thermosiphon according to claim 5, characterized in that, When multiple heat exchange tubes are horizontally arranged in the heat exchange cavity: The steam pressure vessel internally defines independent evaporation and condensation chambers. The primary medium inlets of the multiple heat exchange tubes are connected to the evaporation chamber, the primary medium outlets of the multiple heat exchange tubes are connected to the condensation chamber, the other end of the steam heat exchange tube is connected to the evaporation chamber, and one end of the reflux heat exchange tube is connected to the condensation chamber. The secondary medium inlet is located below the steam pressure vessel and communicates with the heat exchange chamber; the secondary medium outlet is located above the steam pressure vessel and communicates with the heat exchange chamber.

7. The natural circulation reactor steam supply system based on a loop thermosiphon according to claim 6, characterized in that, The steam generator is also equipped with a steam-water separator, which is located at the outlet of the secondary medium.

8. The natural circulation reactor steam supply system based on a loop thermosiphon according to claim 7, characterized in that, A drain valve is connected to the drain outlet at the bottom of the steam-water separator.

9. The natural circulation reactor steam supply system based on a loop thermosiphon according to claim 5, characterized in that, When multiple heat exchange tubes are vertically arranged in the heat exchange cavity: The primary medium inlets of the plurality of heat exchange tubes are connected to the steam heat exchange tubes, and the primary medium outlets of the plurality of heat exchange tubes are connected to the reflux heat exchange tubes. The secondary medium inlet is located below the steam pressure vessel and communicates with the heat exchange chamber; the secondary medium outlet is located above the steam pressure vessel and communicates with the heat exchange chamber.

10. A nuclear power plant, characterized in that, Includes the natural circulation reactor steam supply system based on a loop thermosiphon as described in any one of claims 1 to 9; The working fluid in the heat pipe circulation loop includes, but is not limited to, water and organic working fluids, and the steam generated by the steam generator includes, but is not limited to, water and organic working fluids.

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