Nuclear power generation system and control method based on supercritical carbon dioxide working fluid

Abstract

The invention discloses a nuclear power generation system and control method based on supercritical carbon dioxide working fluid, belonging to the field of nuclear power technology. In order to improve the efficiency and safety of the nuclear power generation system, the nuclear power generation system based on supercritical carbon dioxide working fluid includes a main power generation system, a waste heat removal system, a working fluid loading control system and a working fluid charging and recovery system. The working fluid of the main power generation system, the waste heat removal system, the working fluid loading control system and the working fluid charging and recovery system is supercritical carbon dioxide. The nuclear power generation system and control method can improve the efficiency of thermoelectric conversion, improve the compactness and safety of the system, can be widely used in nuclear power generation systems, replace the power generation system and the waste heat removal system of the traditional water working fluid, realize efficient heat exchange, safe shutdown, and respond to accidents such as emergency shutdown. The working fluid recovery and purification function can also improve energy utilization and reduce waste emissions, which is environmentally friendly and is the development direction of clean energy in the future.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, in particular to a nuclear power generation system based on supercritical carbon dioxide working fluid, and also to a nuclear power generation control method. Background Art

[0002] Nuclear power generation systems are an important method of thermoelectric conversion in the power generation field due to their high power density, stable energy, long-term reliable operation, and environmental friendliness. Fourth-generation reactor types include lead-bismuth reactors, sodium-cooled fast reactors, and other liquid metal reactors. They are more optimized than traditional second- and third-generation nuclear reactors in terms of nuclear safety, economy, reduction of nuclear waste, prevention of nuclear proliferation, elimination of serious accidents, and avoidance of off-site emergencies. Liquid metal reactors have better thermal conductivity and higher safety, and the system layout is highly compact, which is conducive to miniaturization.

[0003] The traditional steam power generation system has low thermoelectric conversion efficiency, high system complexity, more auxiliary systems, and large volume and weight, and the energy conversion form needs to be optimized. In addition, the working fluid of the waste heat removal system commonly used in the reactor in the traditional nuclear power generation system is generally water. The waste heat removal system needs to be equipped with a large-capacity cooling water tank, and the working fluid will undergo phase change in the reactor vessel during the cooling process, which may affect the life of the reactor pressure vessel and cause the reactor safety to decrease. The waste heat extraction of reactor accident shutdown and normal shutdown needs to be combined with the characteristics of the thermoelectric conversion system and the characteristics of the reactor, and a waste heat extraction method with a higher safety factor, more efficiency, and lower failure probability should be designed to avoid safety problems caused by phase change, reduce damage to the reactor vessel, and ensure the integrity of the reactor vessel, thereby improving the safety of normal shutdown and accident shutdown of the reactor.

[0004] The new supercritical carbon dioxide power generation system is a small, clean, efficient, and fast-response closed-loop power generation system. There are multiple loop feedbacks in the system, and the physical properties change dramatically near the critical point. It has strong nonlinear characteristics. The system operation process is sensitive to physical property changes, and the system behavior analysis and control are complex. The system operation mode and control strategy are different from those of traditional steam power generation systems. It is necessary to formulate a new control and operation method based on the working fluid characteristics, system configuration and demand background. There is no comprehensive and systematic research on this in China. Summary of the invention

[0005] In order to improve the safety of existing reactors and the efficiency of nuclear power generation systems, the present invention provides a nuclear power generation system and a control method based on supercritical carbon dioxide working fluid. The nuclear power generation system and the control method based on supercritical carbon dioxide working fluid have the characteristics of high thermoelectric conversion efficiency, high compactness, high inherent safety, and simple and efficient operation control. A liquid metal reactor is provided, which has higher thermal conductivity and inherent safety, and an intermediate heat exchanger is provided inside the reactor, which has higher compactness and is conducive to miniaturization; a main power generation system is provided to complete the conversion of thermal energy into electrical energy, and has the characteristics of high thermoelectric conversion efficiency, small size and rapid load change; an active residual heat removal system and a passive residual heat removal system are provided, which can realize the extraction of core heat energy in the reactor accident state or even the whole plant power outage state, thereby ensuring the safety of the nuclear reactor; a working fluid loading control system is provided to realize the efficient load change function of the power generation system; a working fluid filling and recovery system is provided to provide conditions for the movement of the system of the present invention, and has the ability to provide working fluid filling for the system at any time, and recycles the "waste gas mixture" generated by the system for reuse, thereby improving energy utilization and thermoelectric conversion efficiency and reducing waste emissions; a partitioned efficient load change control method is proposed, including a working fluid loading control method, a bypass regulation control method and a throttling control method, which can match the optimal load regulation means for different load intervals.

[0006] The technical solution adopted by the embodiment of the present invention to solve the technical problem is:

[0007] A nuclear power generation system based on supercritical carbon dioxide working fluid comprises a main power generation system, a waste heat removal system, a working fluid charge control system and a working fluid charging and recovery system, wherein the working fluid of the main power generation system, the waste heat removal system, the working fluid charge control system and the working fluid charging and recovery system are all supercritical carbon dioxide.

[0008] The main power generation system can convert thermal energy into electrical energy. The main power generation system includes a reactor and power generation system equipment. The power generation system equipment includes a turbine, a generator, a high-temperature regenerator, a low-temperature regenerator, a first cooler, a first pressurizing branch, and a second pressurizing branch. The first pressurizing branch is provided with a first compressor stage, a second cooler, and a first compressor stage, respectively. The second pressurizing branch is provided with a second compressor. The working fluid output by the reactor can enter the turbine to perform work. The turbine can drive the generator to generate electricity. The exhaust gas after performing work can enter the high-temperature regenerator and the low-temperature regenerator in turn to release heat. The exhaust gas after releasing heat can enter the high-temperature regenerator and the low-temperature regenerator in turn to release heat. The gas can enter the first cooler to be cooled, the cooled exhausted gas enters the first stage of the first compressor to be compressed, the compressed working fluid is cooled in the second cooler, the cooled working fluid enters the second stage of the first compressor to be compressed again, the high-pressure working fluid compressed by the first stage of the first compressor and the second stage of the first compressor can enter the high-temperature regenerator and the low-temperature regenerator in turn to absorb heat, the exhausted gas at the outlet of the low-temperature regenerator also enters the second compressor to be compressed, the high-pressure working fluid compressed by the second compressor merges with the working fluid at the outlet of the low-temperature regenerator, and then enters the high-temperature regenerator to absorb heat, and the working fluid after absorbing heat can enter the reactor to absorb heat and become a high-temperature and high-pressure working fluid.

[0009] The reactor working fluid outlet is connected to the turbine inlet through the turbine inlet pipeline, the turbine outlet is connected to the heat release inlet of the high-temperature regenerator through the exhaust gas delivery pipeline, the reactor working fluid inlet is connected to the heat absorption outlet of the high-temperature regenerator through the working fluid input pipeline, and the compression outlet of the second stage of the first compressor is connected to the heat absorption inlet of the low-temperature regenerator through the high-pressure working fluid delivery pipeline.

[0010] The turbine inlet pipeline is connected to the exhausted gas delivery pipeline through the turbine bypass pipeline, and the turbine bypass pipeline can realize load regulation and load shedding functions; the working fluid input pipeline is connected to the turbine inlet pipeline through the reactor bypass pipeline, and the reactor bypass pipeline can isolate the reactor and the main power generation system; the high-pressure working fluid delivery pipeline is connected to the inlet end of the first cooler through the first compressor bypass pipeline, and the first compressor bypass pipeline can realize working fluid flow regulation.

[0011] The power generation system equipment also includes a first speed increasing box, a first electric motor, a second speed increasing box, a second electric motor and a speed reducing box. The first compressor stage, the first compressor stage two and the first electric motor are coaxially arranged. The first compressor stage, the first compressor stage two and the first electric motor are connected through gears in the first speed increasing box. The second compressor and the second electric motor are coaxially arranged. The second compressor and the second electric motor are connected through gears in the second speed increasing box. The turbine and the generator are coaxially arranged. The turbine and the generator are connected through gears in the speed reducing box.

[0012] The first cooler, the second cooler, the high-temperature regenerator and the low-temperature regenerator all use PCHE type microchannel high-efficiency heat exchangers, which can achieve small volume and high specific surface area heat exchange.

[0013] The reduction gearbox, the first speed increasing gearbox and the second speed increasing gearbox are all connected to the recovery working fluid inlet pipeline of the working fluid filling and recovery system through the first pipeline, and the inlet end of the first cooler is connected to the working fluid filling outlet pipeline of the main power generation system of the working fluid filling and recovery system through the second pipeline. The working fluid filling and recovery system can fill and recover working fluid.

[0014] The inlet end of the first cooler is connected to the working fluid charge control system outlet pipeline of the working fluid charge control system through the third pipeline, and the outlet end of the second compressor is connected to the working fluid charge control system inlet pipeline of the working fluid charge control system through the fourth pipeline. The working fluid charge control system can change the load of the main power generation system.

[0015] The reactor contains a control rod drive mechanism, a reactor vessel, a core, a coolant, a coolant pump and an intermediate heat exchanger. The control rod drive mechanism can move the core up and down. The core, the coolant, the coolant pump and the intermediate heat exchanger are all located in the reactor vessel. The core can release heat to the coolant. The coolant pump can make the coolant flow. The coolant can release heat to the intermediate heat exchanger. The working fluid in the main power generation system can enter the intermediate heat exchanger to absorb heat. The inlet of the intermediate heat exchanger is connected to the reactor working fluid inlet, and the outlet of the intermediate heat exchanger is connected to the reactor working fluid outlet.

[0016] The intermediate heat exchanger is a PCHE heat exchanger. Multiple intermediate heat exchangers are arranged along the circumference of the reactor vessel. The intermediate heat exchanger contains a high-temperature side and a low-temperature side. The coolant is a liquid metal coolant. The coolant flows on the high-temperature side. The main power generation system working fluid flows on the low-temperature side. The inlet of the intermediate heat exchanger is connected to the reactor working fluid inlet, and the outlet of the intermediate heat exchanger is connected to the reactor working fluid outlet.

[0017] The reactor also contains a heat-conducting inner partition, and the reactor vessel is divided into a working chamber and an auxiliary chamber which are independent of each other by the heat-conducting inner partition. The core, the coolant, the coolant pump and the intermediate heat exchanger are all located in the working chamber of the reactor vessel. The upper part of the auxiliary chamber is annular, and the lower part of the working chamber is sleeved in the upper part of the auxiliary chamber. A waste heat outlet and a waste heat inlet are provided on the reactor vessel, and the waste heat outlet and the waste heat inlet are both connected to the auxiliary chamber.

[0018] The waste heat removal system contains an active waste heat removal system pipeline, in which supercritical carbon dioxide is used as a circulating cooling medium. Along the direction from the inlet end of the active waste heat removal system pipeline to the outlet end of the active waste heat removal system pipeline, a fourth cooler, a first booster pump and a first heater are sequentially arranged on the active waste heat removal system pipeline, the inlet end of the active waste heat removal system pipeline is connected to the reactor working medium outlet, and the outlet end of the active waste heat removal system pipeline is connected to the reactor working medium inlet.

[0019] When the reactor is shut down normally and the pipeline of the active residual heat removal system needs to be put into use for cooling, the first valve on the working fluid input pipeline is closed, and the second valve on the reactor bypass pipeline is opened, so that the high-pressure working fluid that absorbs heat from the high-temperature regenerator does not enter the reactor but enters the turbine through the reactor bypass pipeline, and the working fluid discharged from the reactor working fluid outlet passes through the fourth cooler and the first booster pump in the pipeline of the active residual heat removal system and returns to the reactor working fluid inlet to achieve cooling of the core;

[0020] When the reactor is shut down for maintenance and heating is required to maintain the temperature of the coolant, the working fluid discharged from the reactor working fluid outlet returns to the reactor working fluid inlet through the first booster pump and the first heater in the active residual heat removal system pipeline to achieve heating of the coolant in the core.

[0021] The residual heat removal system contains a passive residual heat removal system pipeline, in which supercritical carbon dioxide is used as a circulating cooling medium. A third cooler is arranged on the passive residual heat removal system pipeline, and the third cooler is located in a water tank. The third cooler is provided with a cold source by the water tank. The inlet end of the passive residual heat removal system pipeline is connected to both the reactor working medium outlet and the residual heat outlet, and the outlet end of the active residual heat removal system pipeline is connected to both the reactor working medium inlet and the residual heat inlet.

[0022] When the reactor is shut down due to an accident and needs to be cooled by the passive residual heat removal system pipeline, the circulating cooling medium in the passive residual heat removal system pipeline enters the reactor from the reactor working medium outlet and the residual heat outlet, and the circulating cooling medium in the reactor enters the passive residual heat removal system pipeline from the reactor working medium inlet and the residual heat inlet.

[0023] The working fluid filling and recovery system comprises a working fluid recovery inlet pipeline, a filling heat exchanger, a working fluid storage tank and a second heater. The outlet end of the working fluid recovery inlet pipeline is connected to the heat release inlet of the filling heat exchanger, the heat release outlet of the filling heat exchanger is connected to the inlet of the working fluid storage tank through a heat release branch pipe, the heat absorption inlet of the filling heat exchanger is connected to the outlet of the working fluid storage tank through a heat absorption inlet branch pipe, the heat absorption outlet of the filling heat exchanger is connected to the inlet of the second heater through a heat absorption outlet branch pipe, the outlet of the second heater is connected to the inlet end of the first cooler through the working fluid filling outlet pipeline of the main power generation system, the outlet of the second heater is also connected to the active waste heat removal system pipeline through the active waste heat removal system filling outlet pipeline and the fifth pipeline in sequence, and the outlet of the second heater is also connected to the passive waste heat removal system pipeline through the passive waste heat removal system filling outlet pipeline and the sixth pipeline in sequence.

[0024] Along the direction from the inlet end of the recovery working fluid inlet pipeline to the outlet end of the recovery working fluid inlet pipeline, the recovery working fluid inlet pipeline is sequentially provided with an induced draft fan, an oil-gas separation cooling device, a high-temperature heating furnace, a dust removal filter and a dryer, the inlet of the high-temperature heating furnace is connected to the exhaust port of the oil-gas separation cooling device, the oil discharge port of the oil-gas separation cooling device is sequentially connected to an oil filter, a sixth cooler and a lubricating oil tank, the heat release branch pipe is provided with a fifth cooler, and the heat absorption inlet branch pipe is provided with a second booster pump.

[0025] The working fluid loading control system includes a working fluid tank, the outlet of the working fluid tank is connected to the outlet pipeline of the working fluid loading control system, the inlet of the working fluid tank is connected to the inlet pipeline of the working fluid loading control system, the working fluid tank is connected to a cooling water pipe row and an electric heating rod, the cooling water pipe row can cool the working fluid in the working fluid tank, and the electric heating rod can heat the working fluid in the working fluid tank.

[0026] A nuclear power generation control method is applied to the above-mentioned nuclear power generation system based on supercritical carbon dioxide working fluid, and the nuclear power generation control method comprises the following steps:

[0027] When the power grid or load changes, the rated load, current load, load variation range and target load of the main power generation system are determined by changing the electrical output of the generator in response to the power grid or load change, wherein the load variation range is the difference between the target load and the current load;

[0028] When it is determined that the current load is less than 50% of the rated load and the variable load amplitude is less than 20% of the rated load, a working fluid loading control method is used to perform variable load response;

[0029] When it is determined that the current load is less than 50% of the rated load and the variable load amplitude is greater than or equal to 20% of the rated load, a bypass regulation control method is used to perform variable load response;

[0030] When it is determined that the current load is ≥ 50% of the rated load and the variable load amplitude is < 20% of the rated load, the working fluid loading control method is used to perform variable load response;

[0031] When it is determined that the current load is ≥ 50% of the rated load and the variable load amplitude is ≥ 20% of the rated load, a throttling control method is used to perform variable load response.

[0032] The working fluid loading control method comprises the following steps:

[0033] The required valve opening under the variable load amplitude is determined based on the current load and the valve opening-load curve, and the valves on the outlet pipeline of the working fluid charge control system and the inlet pipeline of the working fluid charge control system are roughly adjusted. Based on the load deviation between the current load and the required load, the valves on the outlet pipeline of the working fluid charge control system and the inlet pipeline of the working fluid charge control system are finely adjusted using feedback control to achieve precise control of the charge of the working fluid in the working fluid tank and the main power generation system, and ultimately change the output load of the generator.

[0034] The working fluid loading control method comprises the following steps:

[0035] Based on the deviation between the set value of the thermophysical property of the working fluid in the working fluid tank and the measured value of the thermophysical property of the working fluid in the working fluid tank, feedback control is used to adjust the cooling water pipe row and the electric heating rod to overcome the thermophysical property disturbance of the working fluid in the working fluid tank caused by the change of valve opening on the outlet pipeline of the working fluid charging control system and the inlet pipeline of the working fluid charging control system.

[0036] The bypass regulation control method comprises the following steps:

[0037] The valve openings on the turbine bypass line and the compressor bypass line required under the variable load amplitude are determined based on the current load and the valve opening-load curve, the valves on the turbine bypass line and the compressor bypass line are roughly adjusted, and based on the load deviation between the current load and the required load, the valves on the turbine bypass line are fine-tuned using feedback control, and the output load of the generator is ultimately changed by changing the working fluid flow in the main power generation system.

[0038] The throttling control method comprises the following steps:

[0039] The opening of the valve on the turbine inlet pipeline required under the variable load amplitude is determined based on the current load and the valve opening-load curve, the valve on the turbine inlet pipeline is roughly adjusted, and based on the load deviation between the current load and the required load, the valve on the turbine inlet pipeline is fine-tuned using feedback control, and the output load of the generator is ultimately changed by changing the turbine intake volume.

[0040] The beneficial effects of the embodiments of the present invention are: it can improve the thermoelectric conversion efficiency of the nuclear power generation system, improve the system compactness and safety, and can be widely used in nuclear power generation systems to replace traditional water-based power generation systems and water-based waste heat removal systems, achieve efficient heat exchange, safe shutdown, and respond to accidents such as emergency shutdowns. The working fluid recovery and purification function can also improve energy utilization and reduce waste emissions, which is environmentally friendly and is the future development direction of clean energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0042] Figure 1 It is a schematic diagram of the nuclear power generation system based on supercritical carbon dioxide working fluid according to the present invention.

[0043] Figure 2 It is a schematic diagram of the working fluid filling and recovery system.

[0044] Figure 3 It is a schematic diagram of the working fluid loading control system.

[0045] Figure 4 This is a schematic diagram of the reactor.

[0046] Figure 5 It is a flow chart of the nuclear power generation control method.

[0047] Figure 6 It is a flow chart of load control in the working fluid loading control method.

[0048] Figure 7 It is a flow chart of working fluid tank control in working fluid loading control method.

[0049] Figure 8 It is a flow chart of bypass regulation control method.

[0050] Fig. 9 It is a flow chart of the throttling control method.

[0051] The following are the descriptions of the reference numerals:

[0052] 1. Reactor; 2. Intermediate heat exchanger; 3. Turbine; 4. Generator; 5. Speed ​​reducer; 6. High temperature regenerator; 7. Low temperature regenerator; 8. First cooler; 9. First compressor stage 1; 10. First compressor stage 2; 11. First motor; 12. First speed increaser; 13. Second cooler; 14. Second compressor; 15. Second motor; 16. Second speed increaser; 17. Third cooler; 18. Water tank; 19. Fourth cooler; 20. First booster pump; 21. First heater;

[0053] 101, first pipeline; 102, second pipeline; 103, third pipeline; 104, fourth pipeline; 105, fifth pipeline; 106, sixth pipeline; 107, turbine bypass pipeline; 108, reactor bypass pipeline; 109, compressor bypass pipeline; 110, turbine inlet pipeline; 111, exhaust gas pipeline; 112, working fluid input pipeline; 113, high-pressure working fluid pipeline;

[0054] 121, first valve; 122, second valve; 123, third valve; 124, fourth valve; 125, fifth valve; 126, sixth valve; 127, seventh valve; 128, eighth valve; 129, ninth valve; 1210, tenth valve; 1211, eleventh valve;

[0055] 201, working fluid storage tank; 202, fifth cooler; 203, second booster pump; 204, charging heat exchanger; 205, second heater; 206, dryer; 207, dust filter; 208, high-temperature heating furnace; 209, oil-gas separation cooling device; 210, induced draft fan; 211, oil filter; 212, sixth cooler; 213, lubricating oil tank; 214, recovered working fluid inlet pipeline; 215, main power generation system working fluid charging outlet pipeline; 216, active waste heat removal system charging outlet pipeline; 217, passive waste heat removal system charging outlet pipeline;

[0056] 301, working fluid tank; 302, cooling water pipe row; 303, electric heating rod; 304, working fluid loading control system outlet pipeline; 305, working fluid loading control system inlet pipeline;

[0057] 401. Control rod drive mechanism; 402. Reactor vessel; 403. Core; 404. Auxiliary cavity; 405. Coolant pump; 406. Reactor working fluid inlet; 407. Reactor working fluid outlet; 408. Heat-conducting inner partition; 409. Waste heat inlet; 410. Waste heat outlet. DETAILED DESCRIPTION

[0058] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] like Figures 1 to 4 As shown, a nuclear power generation system based on supercritical carbon dioxide working fluid described in an embodiment of the present invention comprises a main power generation system, a waste heat removal system, a working fluid loading control system and a working fluid filling and recovery system, and the working fluid of the main power generation system, the waste heat removal system, the working fluid loading control system and the working fluid filling and recovery system are all supercritical carbon dioxide.

[0060] The nuclear power generation system based on supercritical carbon dioxide working fluid can convert the heat energy in the reactor 1 into electrical energy, and is provided with a supercritical carbon dioxide Brayton cycle power generation system with high thermoelectric conversion efficiency; an intermediate heat exchanger 2 is provided with an integrated compact arrangement built into the reactor 1; an active residual heat removal system and a passive residual heat removal system are provided, which can realize the extraction of core heat energy in the event of an accident in the reactor 1 or even a power outage in the entire plant, thereby ensuring the safety of the nuclear reactor; a working fluid loading control system is provided to realize the efficient variable load function of the power generation system; a working fluid filling and recovery system is provided to provide conditions for the movement of the system of the present invention, and has the ability to provide working fluid filling for the system at any time, and recycles and processes the "waste gas mixture" generated by the system, thereby improving energy utilization and thermoelectric conversion efficiency and reducing waste emissions. The nuclear power generation system based on supercritical carbon dioxide working fluid has the characteristics of high efficiency, compactness, and inherent safety.

[0061] The main power generation system realizes the conversion of thermal energy into electrical energy, and includes a reactor 1 and power generation system equipment. The reactor 1 in the main power generation system adopts a liquid metal reactor, for example, a lead-bismuth reactor, a sodium-cooled fast reactor or other liquid metal reactor, which is a new type of reactor of the fourth generation, and the core coolant is a liquid metal coolant, including but not limited to a lead-bismuth alloy coolant and a sodium coolant, which has the advantage of higher inherent safety.

[0062] The reactor in the main power generation system includes a core 403, a reactor vessel 402, a control rod drive mechanism 401, a coolant pump 405, an intermediate heat exchanger 2, a working chamber and an auxiliary chamber 404. The reactor intermediate heat exchanger 2 adopts a PCHE type high-efficiency and compact heat exchanger, which is built in the reactor vessel 402, has higher compactness and higher inherent safety, and multiple intermediate heat exchangers 2 can be arranged according to the equipment layout space in the reactor, and are arranged in a ring around the core 403. The intermediate heat exchanger 2 is divided into a high-temperature side and a low-temperature side. The core liquid metal coolant flows on the high-temperature side, and the carbon dioxide working fluid flows on the low-temperature side. The entire intermediate heat exchanger is immersed in the core coolant, and the coolant pump 405 provides power for the circulation of the core coolant.

[0063] like Figure 4 As shown, the working fluid circulation process in the reactor 1 is as follows: the working fluid in the main power generation system enters the cold side of the intermediate heat exchanger 2 through the reactor working fluid inlet 406, and flows out from the reactor working fluid outlet 407 after heat exchange with the reactor coolant on the hot side. The hot side working fluid of the intermediate heat exchanger 2 is the reactor coolant, and the optional reactor coolant can be liquid metal. The coolant pump 405 provides circulation power for the reactor coolant, forms flow heat exchange conditions in the reactor vessel, exchanges heat with the core 403, cools the core 403, and transfers heat to the working fluid of the main power generation system. The control rod drive mechanism 401 realizes the regulation of the core power, and the auxiliary cavity 404 provides an interface for extracting the residual heat.

[0064] The working fluid of the power generation system in the main power generation system is supercritical carbon dioxide, and the power generation cycle configuration is an intercooled recompression Brayton cycle. It can also be other cycle configurations, including but not limited to supercritical carbon dioxide single-stage reheat Brayton cycle, supercritical carbon dioxide recompression Brayton cycle, supercritical carbon dioxide reheat Brayton cycle, etc.

[0065] The working process of the power generation system in the main power generation system is as follows: the high-temperature and high-pressure supercritical carbon dioxide working medium coming out of the intermediate heat exchanger 2 in the reactor 1 enters the turbine 3 to work and drive the generator 4 to generate electricity, converting heat energy into electrical energy. The exhaust gas after work enters the hot side of the high-temperature regenerator 6 to preheat the cold side working medium, and then enters the low-temperature regenerator 7 to further release heat. The working medium at the outlet of the low-temperature regenerator 7 is divided into two branches. The first branch enters the first cooler 8 for further cooling. The cooled exhaust gas can enter the first compressor stage 9 and the first compressor stage 10 in turn to be compressed. A second cooler 13 is arranged between the first compressor stage 9 and the first compressor stage 10 to cool the carbon dioxide working medium that is heated due to compression by the first compressor stage 9, reduce the subsequent compression work of the first compressor stage 10, thereby improving the system thermoelectric conversion efficiency. The existence of the second cooler 13 cools the working medium that is heated after compression, reduces the compression power consumption of the second-stage compressor, and finally achieves the goal of improving the efficiency of the thermoelectric conversion system. The working fluid coming out of the second cooler 13 enters the first compressor stage 10 for further pressurization, and then enters the cold side of the low-temperature regenerator 7 for preheating. The first motor 11 provides power for the first compressor stage 9 and the first compressor stage 10. The second branch directly enters the second compressor 14 for pressurization, and the second motor 15 provides power for it. The working fluid pressurized by the second compressor 14 is mixed with the working fluid at the outlet of the low-temperature regenerator 7 and enters the cold side of the high-temperature regenerator 6 for further preheating. The preheated working fluid enters the intermediate heat exchanger 2 to absorb heat. The high-temperature and high-pressure carbon dioxide working fluid after absorbing heat enters the turbine 3 to do work, completing a closed cycle.

[0066] The reactor working fluid outlet 407 is connected to the inlet of the turbine 3 through the turbine inlet pipeline 110, and the outlet of the turbine 3 is connected to the heat release inlet of the high-temperature regenerator 6 through the exhaust gas delivery pipeline 111. The reactor working fluid inlet 406 is connected to the heat absorption outlet of the high-temperature regenerator 6 through the working fluid input pipeline 112, and the heat absorption outlet of the high-temperature regenerator 6 is connected to the heat absorption outlet of the low-temperature regenerator 7. The outlet of the first compressor second stage 10 is connected to the heat absorption inlet of the low-temperature regenerator 7 through the high-pressure working fluid delivery pipeline 113, the turbine inlet pipeline 110 is connected to the exhaust gas delivery pipeline 111 through the turbine bypass pipeline 107, the working fluid input pipeline 112 is connected to the turbine inlet pipeline 110 through the reactor bypass pipeline 108, and the high-pressure working fluid delivery pipeline 113 is connected to the inlet end of the first cooler 8 through the main compressor bypass pipeline 109.

[0067] The reactor 1 also contains a heat-conducting inner partition 408. The reactor vessel 402 is divided by the heat-conducting inner partition 408 to form a mutually independent working chamber and auxiliary chamber 404. The working chamber and the auxiliary chamber 404 are arranged up and down. The core 403, the coolant, the coolant pump 405 and the intermediate heat exchanger 2 are all located in the working chamber of the reactor vessel 402. The upper part of the auxiliary chamber 404 is annular, and the lower part of the working chamber is sleeved in the upper part of the auxiliary chamber 404. The reactor vessel 402 is provided with a waste heat outlet 410 and a waste heat inlet 409, and the waste heat outlet 410 and the waste heat inlet 409 are both connected to the auxiliary chamber 404.

[0068] The power generation system in the main power generation system is provided with a turbine bypass pipeline 107, a reactor bypass pipeline 108, and a main compressor bypass pipeline 109 to achieve system power regulation and control.

[0069] The main compressor unit in the power generation system of the main power generation system includes a first compressor stage 9, a first compressor stage 2 10, a first speed increaser 12, and a first motor 11. The first compressor stage 9 and the first compressor stage 2 10 are coaxially arranged with the first motor 11, connected through the gear in the first speed increaser 12, and a lubricating oil bearing is arranged in the gearbox; the auxiliary compressor includes a second compressor 14, a second speed increaser 16, and a second motor 15. The second compressor 14 is coaxially arranged with the second motor 15, connected through the gear in the second speed increaser 16, and a lubricating oil bearing is arranged in the gearbox; the turbine generator unit includes a turbine 3, a speed reducer 5, and a generator 4. The turbine 3 is coaxially arranged with the generator 4, connected through the gear in the speed reducer 5, and a lubricating oil bearing is arranged in the speed reducer 5; the carbon dioxide working fluid and oil mist mixture generated in the above-mentioned gearbox is recovered through the working fluid filling and purification system to realize working fluid recovery and lubricating oil recovery, and the interface is the first pipeline 101 and the recovered working fluid inlet pipeline 214.

[0070] The power generation system in the main power generation system is provided with a third pipeline 103 and a fourth pipeline 104. The third pipeline 103 is connected to the working fluid loading control system outlet pipeline 304, and the fourth pipeline 104 is connected to the working fluid loading control system inlet pipeline 305, so as to realize variable working fluid loading of the power generation system, thereby realizing the system's efficient variable load function.

[0071] The power generation system in the main power generation system is provided with a first pipeline 101 and a second pipeline 102. The first pipeline 101 is connected to a recovered working fluid inlet pipeline 214, and the second pipeline 102 is connected to a main power generation system working fluid filling outlet pipeline 215, so as to realize the filling and recovery of working fluid and lubricating oil of the power generation system.

[0072] The residual heat removal system of the present invention includes an active residual heat removal system and a passive residual heat removal system.

[0073] The waste heat removal system uses supercritical carbon dioxide as the working fluid. Currently, there is no related invention patent that uses supercritical carbon dioxide as the working fluid of the reactor waste heat removal system. Since supercritical carbon dioxide does not have phase change, it also avoids the thermal stress problem and material fatigue life problem caused by the phase change of water working fluid, which can greatly improve the safety of the reactor, ensure the integrity of the reactor, and reduce the probability of serious accidents. Carbon dioxide working fluid is also the working medium of the power generation system in the main power generation system. The gas source is stable, and the liquid storage tank storage method is convenient for movement and transportation. It has strong environmental adaptability and flexible layout.

[0074] The active residual heat removal system includes a fourth cooler 19 to realize heat removal, a first booster pump 20 to provide power for the working medium circulation, and a first heater 21 to provide heat when the reactor needs heating.

[0075] The working process of the active residual heat removal system is as follows: when the reactor is shut down normally and the active residual heat removal system needs to be put into use to achieve cooling, the first valve 121, the third valve 123, the ninth valve 129, and the tenth valve 1210 are closed, and the fourth valve 124, the fifth valve 125, the eighth valve 128, the eleventh valve 1211, and the second valve 122 are opened, and the power generation system in the main power generation system directly enters the turbine through the reactor bypass pipeline 108 without passing through the intermediate heat exchanger 2 in the core; and the carbon dioxide in the active residual heat removal system is pressurized by the first booster pump 20, flows through the valve eleventh valve 1211 into the intermediate heat exchanger 2 in the reactor 1 to exchange heat with the core coolant, and after the core residual heat is discharged, it enters the fourth cooler 19 through the fourth valve 124 and the eighth valve 128 for cooling, and then enters the core through the first booster pump 20 after cooling, completing the closed cycle and achieving the core residual heat removal. When the reactor is shut down for maintenance and heating is required to maintain the core coolant temperature, the first valve 121, the third valve 123, the eighth valve 128, and the eleventh valve 1211 are closed, and the fourth valve 124, the fifth valve 125, the ninth valve 129, and the eleventh valve 1211 are opened to isolate the power generation system, that is, the power generation system in the main power generation system directly enters the turbine 3 through the reactor bypass pipeline 108 without passing through the intermediate heat exchanger 2 in the core 403; and the carbon dioxide in the active residual heat removal system is pressurized by the first booster pump 20 and enters the first heater 21 for heating. The heated working fluid enters the intermediate heat exchanger 2 to exchange heat with the core coolant. After the core coolant is heated to a specified temperature, it returns to the working fluid first booster pump 20 through the fourth valve 124 and the ninth valve 129, completing the closed cycle and realizing core heating.

[0076] The passive residual heat removal system includes a third cooler 17 for cooling, a water tank 18 for providing a cold source, and corresponding pipe valve connectors. The passive residual heat removal system uses supercritical carbon dioxide as a circulating working fluid, which has the characteristics of high density difference with pressure and temperature changes. By utilizing the strong natural circulation ability of the working fluid brought by the physical characteristics of the working fluid, the passive removal of the core residual heat can be achieved. In the event of an accident in the reactor or even a power outage in the entire plant, the core residual heat can still be removed through the passive residual heat removal system, thereby ensuring the safety of the reactor and preventing the occurrence of serious reactor accidents.

[0077] The working process of the passive residual heat removal system is as follows: when the reactor is shut down due to an accident and the passive residual heat removal system needs to be put into use for cooling, the first valve 121 and the third valve 123 are closed, and the second valve 122, the sixth valve 126, and the seventh valve 127 are opened. The carbon dioxide working medium in the circulation system is divided into two branches to enter the reactor, one of which is connected to the reactor inlet pipeline and enters the core through the reactor inlet pipeline; the other branch enters the auxiliary chamber 404 of the reactor to achieve annular and uniform cooling of the reactor shell, and then merges with the carbon dioxide working medium in the reactor inlet pipeline and flows out from the reactor outlet pipeline. The carbon dioxide working medium heated by the core increases in temperature and pressure, and the working medium density decreases, forming a natural circulation buoyancy in the pipeline, and rises to the high-level water tank 18 through the sixth valve 126, and uses the third cooler 17 therein to achieve heat exchange with water to achieve working medium cooling. The temperature and pressure of the cooled carbon dioxide working medium decreases, and the working medium density increases. Under the action of gravity, it enters the reactor 1 through the seventh valve 127 to continue to be heated, forming a closed passive residual heat cooling circulation loop.

[0078] When the working fluid of the passive residual heat removal system enters the core 403 to extract heat, it enters the reactor in two branches, which can achieve synchronous cooling of the internal components and the reactor barrel, uniform cooling, avoid thermal stress problems and material fatigue life problems, greatly improve the safety of the reactor, ensure the integrity of the reactor, and reduce the probability of serious accidents.

[0079] The working fluid filling and recovery system of the present invention provides carbon dioxide working fluid to the power generation system, active waste heat removal system and passive waste heat removal system in the main power generation system, and at the same time recovers the carbon dioxide working fluid leaked into the speed increaser / reduction gearbox, thereby avoiding the need to replenish the working fluid for long-term power generation operation. Since the carbon dioxide working fluid leaked into the speed increaser / reduction gearbox will mix with the volatile lubricating oil therein to form an oil-gas mixture, the mixture needs to be separated and processed, and then the carbon dioxide working fluid and the lubricating oil are recovered separately, which can improve energy utilization, reduce the emission of system operation waste, and reduce the replenishment of power generation working fluid.

[0080] like Figure 2As shown, the working fluid filling and recovery system of the present invention includes a working fluid storage tank 201 capable of storing low-temperature and low-pressure liquid working fluid, which is used to store liquid carbon dioxide working fluid, provide a gas source for working fluid filling, and store the working fluid in a liquid state, with a small storage space and convenient transportation; includes a second boosting pump 203 for liquid boosting, which provides power for working fluid circulation; includes a filling heat exchanger 204, in order to reduce the configuration capacity of the fifth cooler 202 and the second heater 205, reduce costs and improve economy, the present invention is provided with a filling heat exchanger 204, and uses the waste heat of the recovered working fluid to preheat the working fluid at the outlet of the working fluid storage tank 201; includes It includes a second heater 205, which is used to heat the carbon dioxide working medium to a specified temperature and inject it into the power generation system; it includes a dryer 206, a dust removal filter 207, and a high-temperature heating furnace 208, which use a high-temperature oil mist carbonization method to achieve carbonization treatment of a small amount of oil mist remaining in the carbon dioxide working medium after the oil mist is separated, so as to ensure the purity of the recovered working medium; it includes an oil-gas separation cooling device 209, which realizes the separation of oil mist and carbon dioxide working medium; it includes an oil filter 211, a sixth cooler 212 and a lubricating oil tank 213. This branch completes the recovery, filtration and storage of the lubricating oil after the oil mist and carbon dioxide working medium are separated.

[0081] The working process of the working fluid filling and recovery system of the present invention is as follows:

[0082] The working fluid filling process is as follows: the liquid carbon dioxide working fluid coming out of the working fluid storage tank 201 is pressurized by the second booster pump 203 and enters the filling heat exchanger 204 for preheating, and after absorbing heat, enters the second heater 205 for further heating, and the working fluid heated to the specified temperature enters the corresponding system for filling through the main power generation system working fluid filling outlet pipeline 215, the active waste heat removal system filling outlet pipeline 216 or the passive waste heat removal system filling outlet pipeline 217. For example, the outlet of the second heater 205 is also connected to the active waste heat removal system pipeline through the active waste heat removal system filling outlet pipeline 216 and the fifth pipeline 105 in sequence, and the outlet of the second heater 205 is also connected to the passive waste heat removal system pipeline through the passive waste heat removal system filling outlet pipeline 217 and the sixth pipeline 106 in sequence.

[0083] The working medium recovery process is as follows: the oil mist working medium mixture coming out of the speed increaser / reduction gearbox enters the recovery working medium inlet pipeline 214 through the first pipeline 101, and enters the oil-gas separation cooling device 209 via the induced draft fan 210 to realize the rough separation of the carbon dioxide working medium and the oil mist. The separated oil mist is purified and recovered by the oil filter 211 and the sixth cooler 212, and finally injected into the lubricating oil tank 213 for storage; the carbon dioxide working medium separated from the oil-gas separation cooling device 209 contains a trace amount of oil mist, which is further heated and carbonized in the high-temperature heating furnace 208 to ensure the purity of the separated working medium, forming particles attached to the volume wall surface, and the separated pure carbon dioxide working medium enters the dust removal filter 207 and the dryer 206 in turn for purification, and then enters the filling heat exchanger 204 to preheat the liquid working medium at the outlet of the storage tank, and finally passes through the fifth cooler 202 to be cooled to liquid state and injected back into the working medium storage tank.

[0084] like Figure 3 As shown, the working fluid charge control system of the present invention can realize the requirements of efficient and rapid load change of the power generation system, and utilizes the high density difference generated by the density of the carbon dioxide working fluid changing with the pressure and temperature at any time to change the charge of the working fluid in the power generation system loop, thereby changing the power of the turbine generator set. It includes a working fluid tank 301 for holding the system working fluid, a cooling water pipe row 302 for cooling the working fluid and changing the pressure and density of the working fluid in the storage tank, an electric heating rod 303 for heating the working fluid and changing the pressure and density of the working fluid in the storage tank, and the inlet / outlet pipeline of the working fluid charge control system realizes the replacement of the working fluid.

[0085] The working process of the working fluid charge control system of the present invention is as follows: the working fluid charge control system inlet pipeline 305 is connected to the fourth pipeline 104 , and the working fluid charge control system outlet pipeline 304 is connected to the third pipeline 103 . When the system needs to reduce the load, the valve on the inlet pipeline 305 of the working fluid loading control system is opened, and the valve on the outlet pipeline 304 of the working fluid loading control system is closed. The high-pressure working fluid at the outlet of the second compressor 14 enters the working fluid tank 301 under the action of the pressure difference, the working fluid of the power generation system is reduced, the working capacity is reduced, and the output electric power is reduced to respond to the load reduction action; when the system needs to increase the load, it is necessary to send the carbon dioxide working fluid in the working fluid tank 301 back to the power generation system through the outlet pipeline 304 of the working fluid loading control system based on the density difference, that is, the pressure difference. The working fluid at the third pipeline 103 is the low-pressure section of the system. The pressure change in the working fluid tank 301 is achieved by controlling the cooling function of the cooling water pipe row 302 and the heating function of the electric heating rod 303, so that the working fluid density in the working fluid tank is always higher than the working fluid density in the third pipeline 103. At this time, under the action of the pressure difference, the working fluid enters the power generation system, the working fluid of the power generation system is increased, the working capacity is increased, and the output electric power is increased to respond to the load increase action.

[0086] The characteristics of the working fluid charge control system of the present invention include that it can realize low-energy consumption variable load control, without setting up a power source such as a working fluid pump, and utilizes the physical property of high density difference of the carbon dioxide working fluid itself at different temperatures to realize automatic replacement cycle of the working fluid; the heating and cooling functions are set to realize the adjustable pressure and temperature of the working fluid in the working fluid tank to adapt to the variable load requirements of different working conditions, and the cooling function can also reduce the volume of the configured working fluid tank; it has the function of efficient and rapid load change, and responds to load changes by changing the loop charge of the power generation system, which is more economical than conventional throttling regulation and bypass regulation to realize load changes, and there is no energy waste.

[0087] The system described in the present invention is a closed power generation cycle system, and there is loop feedback, such as turbine back pressure is related to compressor inlet pressure, compressor outlet pressure is related to turbine inlet pressure, and parameter changes of one device of compressor or turbine will affect the other device. The system loop includes two compressors, and there is flow distribution between the first compressor and the second compressor 14; the two compressors have different working points and different operating characteristics, and compressor control and operation matching need to be considered. The inlet of the first compressor is close to the critical point, and the physical properties change violently near the critical point, with strong nonlinear characteristics. The system operation process is sensitive to physical property changes, and the system behavior analysis and control are complex. The system adopts high-temperature regenerator 6 and low-temperature regenerator 7, the hot side and cold side fluid temperatures affect each other, the heat source outlet temperature and the inlet temperature are coupled to each other, the compressor outlet temperature and the inlet temperature are coupled to each other, and the system coupling characteristics are strong. It is necessary to establish targeted control strategies and methods for the system in combination with the characteristics of variable load requirements, working fluid characteristics, system configuration and control means. The efficient, compact and inherently safe advanced nuclear energy system control method proposed by the present invention is partitioned efficient variable load control. It includes working fluid loading control method, bypass regulation control method and throttling control method, which can match the optimal load regulation method for different load ranges.

[0088] The nuclear power generation control method is introduced below. The nuclear power generation control method of the present invention has the characteristics of high efficiency, simplicity, speed and energy saving. When the load level of the system itself is high (such as higher than 50% load level), it is suitable to select an efficient load change method to achieve energy saving and high efficiency as much as possible without wasting the system heat energy. At this time, the working fluid loading control method and the throttling control method are most suitable for realizing system load change. The working principle of the working fluid loading control method is to adjust the system load by increasing or reducing the working fluid mass in the loop. The advantage of this control method is that when the power changes, the system efficiency can be better maintained, but this control method requires a working fluid storage tank for storage. For high-power devices, the volume of the storage tank may be very large. Considering the economy, this method is more suitable for use in small-scale load adjustment. Therefore, the control method of the present invention divides the load change amplitude (with 20% load amplitude as the limit). The working principle of the throttling control method is to adjust the turbine main gas regulating valve, that is, the valve opening on the turbine inlet pipeline 110, to achieve the change of the speed and the working fluid flow, thereby realizing the adjustment of the system load. The advantage of this control method is that there is no waste of working fluid energy during the load change process, the system efficiency can be maintained, and the adjustment rate is fast. When the system load level is low (such as less than 50% load level), the system efficiency is not a priority factor. Simple and direct load change means will be more applicable under the requirements of frequent load changes. At this time, it is more appropriate to use the working fluid loading control method and the bypass adjustment control method. The working principle of the bypass adjustment method is to achieve load change by bypassing the working fluid and changing the working mass entering the turbine to do work. The advantages of this control method are fast and simple, and it is suitable for frequent operation. The disadvantage is that it wastes the energy of the system and reduces the efficiency of the system when the load changes. From the perspective of energy saving, it is not suitable for use at high power levels and large load changes. Therefore, the system control method proposed in the present invention also distinguishes the load change amplitude for low load levels, and combines the characteristics of the working fluid loading control method and the bypass adjustment method to perform load adjustment. Specific examples are as follows:

[0089] like Figure 5As shown, the pre-processor monitors the load demand of the external power grid in real time, compares it with the measured load to generate a variable load instruction, and determines the variable load control method to be executed in combination with the current load level and the variable load amplitude. If the load level is less than 50%, it continues to determine whether the variable load amplitude is less than 20%. If it is less than 20%, the working fluid loading control method is used for variable load control, and the first processing module is entered. After adjustment by the first processing module, the output power is changed, and the current measured load is fed back to the pre-processor to form a closed-loop load control. On the contrary, if the variable load amplitude is greater than or equal to 20%, the bypass adjustment control method is used to enter the second processing module. After adjustment by the second processing module, the output power is changed, and the current measured load is fed back to the pre-processor to form a closed-loop load control. If the load level is greater than or equal to 50%, it continues to determine whether the variable load amplitude is less than 20%. If it is less than 20%, the working fluid loading control method is used for variable load control, and the first processing module is entered. The output power is changed after adjustment by the first processing module, and the current measured load is fed back to the pre-processor to form a closed-loop load control; on the contrary, if the variable load amplitude is greater than or equal to 20%, the throttling control method is adopted, and the third processor is entered. The output power is changed after adjustment by the third processor, and the measured load is fed back to the pre-processor.

[0090] Among them, the first processing module is as follows Figure 6 and Figure 7 As shown, it is divided into load control part and working fluid tank control part. Figure 6 is a schematic diagram of the load control part in the first processing module, Figure 7 The schematic diagram of the working fluid tank control part in the first processing module. The load control part is a priori-feedback closed-loop follow-up control structure. When the target load is received, it enters the priori channel on the one hand, and performs coarse adjustment of the valve position according to the valve opening-load curve to improve the rapid responsiveness to load changes. The other part enters the feedback channel, generates a load difference by comparing with the load measurement value, and uses the valve position PID controller to adjust the valve opening on the working fluid loading control system outlet pipeline 304 and the working fluid loading control system inlet pipeline 305, thereby changing the loading of the working fluid in the storage tank, and then changing the loading of the working fluid in the main power generation system, and realizing accurate control of the output load to meet the accurate follow-up requirements for load changes. The working fluid tank control part is a single closed-loop constant value control structure, the purpose of which is to overcome the thermal physical property disturbance of the working fluid tank 301 caused by the change of the valve opening of the working fluid tank outlet and inlet pipelines by adjusting the cooling water pipe row 302 and the electric heating rod 303, so as to maintain good adjustment performance.

[0091] The specific implementation includes but is not limited to: after receiving the target load, firstly, based on the valve opening-load curve (which can be obtained through a limited number of experiments), the valve opening on the inlet pipeline 305 of the working fluid charge control system and the outlet pipeline 304 of the working fluid charge control system are obtained to achieve the valve rough adjustment. Next, the target load is compared with the load measurement value to obtain the load difference. When the difference is a positive value, it is necessary to increase the electric power output of the generator 4 and increase the work output of the turbine 3. At this time, the regulating valve on the inlet pipeline 305 of the working fluid charge control system is closed, and the valve on the outlet pipeline 304 of the working fluid charge control system is finely adjusted through the working fluid charge PID controller, and high-pressure and high-density working fluid is injected into the main power generation system, thereby increasing the working fluid charge of the main power generation system and improving the power generation output, so as to achieve the following of the load demand. On the contrary, when the difference is negative, it is necessary to reduce the electric power output of the generator 4, and the turbine work output needs to be reduced. At this time, the regulating valve on the outlet pipeline 304 of the working fluid loading control system is closed, and the valve on the inlet pipeline 305 of the working fluid loading control system is fine-tuned through the working fluid loading PID controller, so that the high-pressure and high-density main power generation system working fluid at the interface of the fourth pipeline 104 enters the storage tank, thereby reducing the working fluid loading of the main power generation system and reducing the power generation output, so as to achieve the following of the load demand. In addition, during the valve adjustment process, the thermal properties of the working fluid tank will change due to the change in the working fluid tank loading, resulting in a decrease in the adjustment performance. In order to maintain good adjustment performance, it is necessary to maintain the thermal properties of the working fluid tank 301 near the set value. When the working fluid is filled, the temperature and pressure of the working fluid tank rises. At this time, the electric heating rod 303 is closed, and the cooling water PID controller is used to adjust the cooling water pipe row 302 to increase the cooling water volume, so as to achieve the purpose of reducing the working fluid pressure and temperature in the working fluid tank 301, so as to facilitate the main power generation system working fluid to be filled into the working fluid tank. When the working fluid is discharged, the temperature and pressure of the working fluid tank decreases. At this time, the cooling water pipe row 302 is closed and the heating power of the electric heating rod 303 is increased through the PID controller of the electric heating rod 303, so as to achieve the purpose of increasing the pressure and temperature of the working fluid in the working fluid tank 301, and facilitate the working fluid tank to inject the working fluid into the main power generation system. It is worth mentioning that the electric heating rod 303 and the cooling water pipe row 302 set in the present invention will continuously monitor the deviation of the thermal properties in the working fluid tank from the set value after each load conversion of the working fluid loading control system. When a deviation occurs, the working fluid in the storage tank can be restored to the expected and set pressure and temperature state by heating and cooling to maintain good regulation performance, so as to better realize the next variable load condition execution.

[0092] The second processing module is Figure 8As shown, a dual priori-single feedback follow-up control structure is adopted. When the target load is received, one part enters the priori channel and performs coarse adjustment of the valve position of the valves on the turbine bypass pipeline 107 and the compressor bypass pipeline 109 according to the valve opening-load curve to improve the rapid response to load changes. The other part enters the feedback channel, in which the feedback channel only acts on the valve on the turbine bypass pipeline 107 to ensure control stability, generates a load difference by comparing with the load measurement value, and uses the valve position PID controller to adjust the valve opening on the turbine bypass pipeline 107, thereby changing the working fluid flow of the main power generation system, and ultimately affecting the turbine work and the generator output power, so as to accurately respond to the load change requirements.

[0093] The specific implementation includes but is not limited to: after receiving the target load, firstly, based on the valve opening-load curve (which can be obtained through a limited number of experiments), the valve opening on the turbine bypass pipeline 107 and the compressor bypass pipeline 109 is obtained to achieve valve coarse adjustment. Next, the target load is compared with the load measurement value to obtain the load difference. If the calculated load deviation is a negative value, it is necessary to increase the electric power output of the generator 4 and increase the work output of the turbine 3. At this time, the valve position PID controller is used to fine-tune the valve on the turbine bypass pipeline 107 to reduce the working fluid flow through the turbine bypass pipeline 107, so that the working fluid flow through the main power generation system is increased, thereby achieving an increase in power generation output and following the load demand. On the contrary, the working fluid flow through the turbine bypass pipeline 107 is increased, so that the working fluid flow through the main power generation system is reduced, thereby achieving a reduction in power generation output and following the load demand. This adjustment method is a bypass adjustment control method.

[0094] The third processing module is Fig. 9 As shown, the priori-feedback follow-up control structure is adopted. When the target load is received, one part enters the priori channel and performs a rough adjustment of the valve position of the turbine intake valve on the turbine inlet pipeline 110 according to the valve opening-load curve to improve the rapid response to load changes. The other part enters the feedback channel, generates a load difference by comparing it with the load measurement value, and uses the valve position PID controller to adjust the opening of the turbine intake valve on the turbine inlet pipeline 110, thereby changing the turbine intake volume, and ultimately affecting the turbine work and the generator output power, so as to accurately respond to the load change requirements.

[0095] The specific implementation includes but is not limited to: after receiving the target load, firstly, based on the valve opening-load curve (which can be obtained through a limited number of experiments), the opening of the turbine intake valve on the turbine inlet pipeline 110 is obtained to achieve coarse adjustment of the valve. Next, the target load is compared with the load measurement value to obtain the load difference. If the calculated load deviation is a negative value, it is necessary to increase the electric power output of the generator 4 and increase the work output of the turbine 3. At this time, the turbine intake valve on the turbine inlet pipeline 110 is finely adjusted through the valve position PID controller to increase the turbine intake volume, thereby increasing the turbine work output and the generator output electric power, thereby achieving load demand tracking. On the contrary, the turbine intake volume is reduced, thereby reducing the turbine work output and reducing the generator output electric power, thereby achieving load demand tracking. This adjustment method is a throttling control method.

[0096] The working fluid loading control method corresponds to the first processing module, the bypass adjustment control method corresponds to the second processing module, and the throttling control method corresponds to the third processing module. The above is only a specific embodiment of the present invention, and the scope of the invention cannot be limited by it. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the present invention should still fall within the scope covered by the present invention. In addition, the technical features and technical features, technical features and technical solutions, technical solutions and technical solutions, and embodiments and embodiments in the present invention can be freely combined and used.

Claims

1. A nuclear power generation system based on supercritical carbon dioxide working fluid, characterized in that: The nuclear power generation system based on supercritical carbon dioxide working fluid comprises a main power generation system, a waste heat removal system, a working fluid loading control system and a working fluid charging and recovery system, and the working fluids of the main power generation system, the waste heat removal system, the working fluid loading control system and the working fluid charging and recovery system are all supercritical carbon dioxide; The main power generation system is capable of converting thermal energy into electrical energy. The main power generation system comprises a reactor (1) and power generation system equipment. The power generation system equipment comprises a turbine (3), a generator (4), a high-temperature regenerator (6), a low-temperature regenerator (7), a first cooler (8), a first pressurizing branch and a second pressurizing branch. The first pressurizing branch is provided with a first compressor stage (9), a second cooler (13) and a first compressor stage (10) in sequence. The second pressurizing branch is provided with a second compressor (14). The working fluid output by the reactor (1) can enter the turbine (3) to perform work. The turbine (3) can drive the generator (4) to generate electricity. The exhaust gas after performing work can enter the high-temperature regenerator (6) and the low-temperature regenerator (7) in sequence to release heat. After releasing heat, the exhaust gas can enter the high-temperature regenerator (6) and the low-temperature regenerator (7) in sequence to release heat. The exhaust gas can enter the first cooler (8) for cooling, the cooled exhaust gas enters the first stage (9) of the first compressor for compression, the compressed working fluid is cooled in the second cooler (13), the cooled working fluid enters the second stage (10) of the first compressor for compression again, the high-pressure working fluid compressed by the first stage (9) of the first compressor and the second stage (10) of the first compressor can enter the high-temperature regenerator (6) and the low-temperature regenerator (7) in sequence for heat absorption, the exhaust gas at the outlet of the low-temperature regenerator (7) also enters the second compressor (14) for compression, the high-pressure working fluid compressed by the second compressor (14) merges with the working fluid at the outlet of the low-temperature regenerator (7), and then enters the high-temperature regenerator (6) for heat absorption, and the working fluid after heat absorption can enter the reactor (1) for heat absorption to become a high-temperature and high-pressure working fluid; The power generation system equipment also includes a first speed increasing box (12), a first motor (11), a second speed increasing box (16), a second motor (15) and a speed reducing box (5); The residual heat removal system comprises an active residual heat removal system pipeline, in which supercritical carbon dioxide is used as a circulating cooling medium. A fourth cooler (19), a first booster pump (20) and a first heater (21) are sequentially arranged on the active residual heat removal system pipeline along the direction from the inlet end of the active residual heat removal system pipeline to the outlet end of the active residual heat removal system pipeline. The inlet end of the active residual heat removal system pipeline is connected to the reactor working medium outlet (407), and the outlet end of the active residual heat removal system pipeline is connected to the reactor working medium inlet (406); The residual heat removal system further comprises a passive residual heat removal system pipeline, in which supercritical carbon dioxide is used as a circulating cooling medium, a third cooler (17) is arranged on the passive residual heat removal system pipeline, the third cooler (17) is located in a water tank (18), and the third cooler (17) is provided with a cold source by the water tank (18), the inlet end of the passive residual heat removal system pipeline is connected to both the reactor working medium outlet (407) and the residual heat outlet (410), and the outlet end of the active residual heat removal system pipeline is connected to both the reactor working medium inlet (406) and the residual heat inlet (409); The inlet end of the first cooler (8) is connected to the working fluid loading control system outlet pipeline (304) of the working fluid loading control system through a third pipeline (103), and the outlet end of the second compressor (14) is connected to the working fluid loading control system inlet pipeline (305) of the working fluid loading control system through a fourth pipeline (104), and the working fluid loading control system is capable of changing the load of the main power generation system; The working fluid loading control system comprises a working fluid tank (301), the outlet of the working fluid tank (301) is connected to an outlet pipeline (304) of the working fluid loading control system, the inlet of the working fluid tank (301) is connected to an inlet pipeline (305) of the working fluid loading control system, the working fluid tank (301) is connected to a cooling water pipe row (302) and an electric heating rod (303), the cooling water pipe row (302) can cool the working fluid in the working fluid tank (301), and the electric heating rod (303) can heat the working fluid in the working fluid tank (301); The reduction gearbox (5), the first speed increasing gearbox (12) and the second speed increasing gearbox (16) are all connected to the recovered working fluid inlet pipeline (214) of the working fluid filling and recovery system through the first pipeline (101); the inlet end of the first cooler (8) is connected to the working fluid filling outlet pipeline (215) of the main power generation system of the working fluid filling and recovery system through the second pipeline (102); the working fluid filling and recovery system is capable of filling and recovering working fluid; The working fluid filling and recovery system comprises a working fluid recovery inlet pipeline (214), a filling heat exchanger (204), a working fluid storage tank (201) and a second heater (205). The outlet end of the working fluid recovery inlet pipeline (214) is connected to the heat release inlet of the filling heat exchanger (204), the heat release outlet of the filling heat exchanger (204) is connected to the inlet of the working fluid storage tank (201) through a heat release branch pipe, the heat absorption inlet of the filling heat exchanger (204) is connected to the outlet of the working fluid storage tank (201) through a heat absorption inlet branch pipe, and the heat absorption outlet of the filling heat exchanger (204) is connected to the outlet of the working fluid storage tank (201) through a heat absorption outlet branch pipe. The outlet of the second heater (205) is connected to the inlet of the second heater (205), and the outlet of the second heater (205) is connected to the inlet of the first cooler (8) through the main power generation system working fluid filling outlet pipeline (215). The outlet of the second heater (205) is also connected to the active waste heat removal system pipeline through the active waste heat removal system filling outlet pipeline (216) and the fifth pipeline (105) in sequence. The outlet of the second heater (205) is also connected to the passive waste heat removal system pipeline through the passive waste heat removal system filling outlet pipeline (217) and the sixth pipeline (106) in sequence.

2. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 1 is characterized in that: The reactor working fluid outlet (407) is connected to the inlet of the turbine (3) through the turbine inlet pipeline (110), the outlet of the turbine (3) is connected to the heat release inlet of the high-temperature regenerator (6) through the exhaust gas delivery pipeline (111), the reactor working fluid inlet (406) is connected to the heat absorption outlet of the high-temperature regenerator (6) through the working fluid input pipeline (112), and the compression outlet of the second stage (10) of the first compressor is connected to the heat absorption inlet of the low-temperature regenerator (7) through the high-pressure working fluid delivery pipeline (113).

3. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 2 is characterized in that: The turbine inlet pipeline (110) is connected to the exhaust gas delivery pipeline (111) through the turbine bypass pipeline (107), and the turbine bypass pipeline (107) can realize load regulation and load shedding functions; the working fluid input pipeline (112) is connected to the turbine inlet pipeline (110) through the reactor bypass pipeline (108), and the reactor bypass pipeline (108) can realize isolation of the reactor (1) and the main power generation system; the high-pressure working fluid delivery pipeline (113) is connected to the inlet end of the first cooler (8) through the first compressor bypass pipeline (109), and the first compressor bypass pipeline (109) can realize working fluid flow regulation and load regulation functions.

4. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 1, characterized in that: The first compressor stage (9), the first compressor stage two (10) and the first motor (11) are coaxially arranged, and the first compressor stage (9), the first compressor stage two (10) and the first motor (11) are connected via gears in a first speed increasing box (12); the second compressor (14) and the second motor (15) are coaxially arranged, and the second compressor (14) and the second motor (15) are connected via gears in a second speed increasing box (16); the turbine (3) and the generator (4) are coaxially arranged, and the turbine (3) and the generator (4) are connected via gears in a speed reducing box (5).

5. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 4 is characterized in that: The first cooler (8), the second cooler (13), the high-temperature regenerator (6) and the low-temperature regenerator (7) all adopt PCHE type microchannel high-efficiency heat exchangers, which can achieve small volume and high specific surface area heat exchange.

6. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 2, characterized in that: The reactor (1) comprises a control rod drive mechanism (401), a reactor vessel (402), a core (403), a coolant, a coolant pump (405) and an intermediate heat exchanger (2). The control rod drive mechanism (401) can move the core (403) up and down. The core (403), the coolant, the coolant pump (405) and the intermediate heat exchanger (2) are all located in the reactor vessel (402). The core (403) can release heat to the coolant. The coolant pump (405) can make the coolant flow. The coolant can release heat to the intermediate heat exchanger (2). The working fluid in the main power generation system can enter the intermediate heat exchanger (2) to absorb heat. The inlet of the intermediate heat exchanger (2) is connected to the reactor working fluid inlet (406), and the outlet of the intermediate heat exchanger (2) is connected to the reactor working fluid outlet (407).

7. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 6, characterized in that: The intermediate heat exchanger (2) is a PCHE heat exchanger. Multiple intermediate heat exchangers (2) are arranged along the circumference of the reactor vessel (402). The intermediate heat exchanger (2) has a high temperature side and a low temperature side. The coolant is a liquid metal coolant. The coolant flows on the high temperature side, and the main power generation system working fluid flows on the low temperature side. The inlet of the intermediate heat exchanger (2) is connected to the reactor working fluid inlet (406), and the outlet of the intermediate heat exchanger (2) is connected to the reactor working fluid outlet (407).

8. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 6, characterized in that: The reactor (1) further comprises a heat-conducting inner baffle (408), and the reactor vessel (402) is divided by the heat-conducting inner baffle (408) to form a mutually independent working chamber and auxiliary chamber (404). The core (403), the coolant, the coolant pump (405) and the intermediate heat exchanger (2) are all located in the working chamber of the reactor vessel (402), the upper part of the auxiliary chamber (404) is annular, and the lower part of the working chamber is sleeved in the upper part of the auxiliary chamber (404). The reactor vessel (402) is provided with a residual heat outlet (410) and a residual heat inlet (409), and the residual heat outlet (410) and the residual heat inlet (409) are both connected to the auxiliary chamber (404).

9. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 1, characterized in that: When the reactor (1) is shut down normally and the pipeline of the active residual heat removal system needs to be put into use for cooling, the first valve (121) on the working fluid input pipeline (112) is closed, and the second valve (122) on the reactor bypass pipeline (108) is opened, so that the high-pressure working fluid that absorbs heat from the high-temperature regenerator (6) does not enter the reactor (1) but enters the turbine (3) through the reactor bypass pipeline (108), and the working fluid discharged from the reactor working fluid outlet (407) passes through the fourth cooler (19) and the first booster pump (20) in the pipeline of the active residual heat removal system and returns to the reactor working fluid inlet (406), thereby cooling the core (403); When the reactor (1) is shut down for maintenance and heating is required to maintain the temperature of the coolant, the working fluid discharged from the reactor working fluid outlet (407) returns to the reactor working fluid inlet (406) through the first booster pump (20) and the first heater (21) in the active residual heat removal system pipeline, thereby achieving heating of the coolant in the core (403).

10. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 1, characterized in that: When the reactor (1) is shut down due to an accident and needs to be cooled by the passive residual heat removal system pipeline, the circulating cooling medium in the passive residual heat removal system pipeline enters the reactor (1) from the reactor working medium outlet (407) and the residual heat outlet (410), and the circulating cooling medium in the reactor (1) enters the passive residual heat removal system pipeline from the reactor working medium inlet (406) and the residual heat inlet (409).

11. The nuclear power generation system based on supercritical carbon dioxide working fluid according to claim 1, characterized in that: Along the direction from the inlet end of the recovered working fluid inlet pipeline (214) to the outlet end of the recovered working fluid inlet pipeline (214), an induced draft fan (210), an oil-gas separation cooling device (209), a high-temperature heating furnace (208), a dust removal filter (207) and a dryer (206) are sequentially arranged on the recovered working fluid inlet pipeline (214); the inlet of the high-temperature heating furnace (208) is connected to the exhaust port of the oil-gas separation cooling device (209); the oil discharge port of the oil-gas separation cooling device (209) is sequentially connected to an oil filter (211), a sixth cooler (212) and a lubricating oil tank (213); the heat release branch pipe is provided with a fifth cooler (202); and the heat absorption inlet branch pipe is provided with a second booster pump (203).

12. A nuclear power generation control method, characterized in that: The nuclear power generation control method is applied to the nuclear power generation system based on supercritical carbon dioxide as claimed in claim 1, and the nuclear power generation control method comprises the following steps: When the power grid or load changes, the rated load, current load, load variation range and target load of the main power generation system are determined by changing the electrical output of the generator (4) in response to the power grid or load change, wherein the load variation range is the difference between the target load and the current load; When it is determined that the current load is less than 50% of the rated load and the variable load amplitude is less than 20% of the rated load, a working fluid loading control method is used to perform variable load response; When it is determined that the current load is less than 50% of the rated load and the variable load amplitude is greater than or equal to 20% of the rated load, a bypass regulation control method is used to perform variable load response; When it is determined that the current load is ≥ 50% of the rated load and the variable load amplitude is < 20% of the rated load, the working fluid loading control method is used to perform variable load response; When it is determined that the current load is ≥ 50% of the rated load and the variable load amplitude is ≥ 20% of the rated load, a throttling control method is used to perform variable load response.

13. The nuclear power generation control method according to claim 12, characterized in that: The working fluid loading control method comprises the following steps: The valve opening required under the variable load amplitude is determined based on the current load and the valve opening-load curve, and the valves on the working fluid charge control system outlet pipeline (304) and the working fluid charge control system inlet pipeline (305) are roughly adjusted. Based on the load deviation between the current load and the required load, the valves on the working fluid charge control system outlet pipeline (304) and the working fluid charge control system inlet pipeline (305) are finely adjusted using feedback control to achieve precise control of the charge of the working fluid in the working fluid tank (301) and the main power generation system, and ultimately change the output load of the generator (4).

14. The nuclear power generation control method according to claim 13, characterized in that: The working fluid loading control method comprises the following steps: Based on the deviation between the set value of the thermal property of the working fluid in the working fluid tank (301) and the measured value of the thermal property of the working fluid in the working fluid tank (301), the cooling water pipe row (302) and the electric heating rod (303) are adjusted by feedback control to overcome the thermal property disturbance of the working fluid in the working fluid tank (301) caused by the change of the valve opening on the outlet pipeline (304) of the working fluid loading control system and the inlet pipeline (305) of the working fluid loading control system.

15. The nuclear power generation control method according to claim 12, characterized in that: The bypass regulation control method comprises the following steps: The valve openings on the turbine bypass pipeline (107) and the compressor bypass pipeline (109) required under the variable load amplitude are determined based on the current load and the valve opening-load curve, the valves on the turbine bypass pipeline (107) and the compressor bypass pipeline (109) are roughly adjusted, and based on the load deviation between the current load and the required load, the valves on the turbine bypass pipeline (107) are finely adjusted using feedback control, and the output load of the generator (4) is ultimately changed by changing the working fluid flow in the main power generation system.

16. The nuclear power generation control method according to claim 12, characterized in that: The throttling control method comprises the following steps: The valve opening on the turbine inlet pipeline (110) required under the variable load range is determined based on the current load and the valve opening-load curve, the valve on the turbine inlet pipeline (110) is roughly adjusted, and based on the load deviation between the current load and the required load, the valve on the turbine inlet pipeline (110) is finely adjusted using feedback control, and the output load of the generator (4) is finally changed by changing the air intake of the turbine (3).

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