Control system and method for nuclear power plant coupled with heat pipe reactor and sCO2 brayton cycle

Abstract

The application discloses a nuclear power device control system and method coupled with a heat pipe reactor and an sCO2 Brayton cycle, including a rotating shaft rotating speed control system and method, which maintains the rotating shaft rotating speed constant by adjusting the working medium flow entering the turbine, so as to ensure the power supply quality of the whole system; a compressor inlet temperature and inlet pressure control system and method, which respectively maintains the compressor inlet temperature and inlet pressure constant by adjusting the seawater flow and the pressure tank pressure, so as to ensure that the temperature and density of the working medium at the compressor inlet are in a supercritical state; and an intermediate heat exchanger outlet temperature control system and method, which adjusts the reactor power by controlling the core reactivity, and then maintains the intermediate heat exchanger outlet temperature constant. The application can provide a reference for the control system design of a high-efficiency compact nuclear power device coupled with a heat pipe reactor and a supercritical carbon dioxide Brayton cycle.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nuclear reactor control, and particularly relates to a control method and system of a nuclear power device coupled with a heat pipe reactor and an sCO2 Brayton cycle. BACKGROUND

[0002] At present, nuclear power devices generally adopt a double-loop principle structure, that is, a nuclear power device includes a one-loop system composed of a nuclear reactor and a coolant loop and a two-loop system composed of a power cycle system. In terms of the one-loop system structure, a heat pipe reactor (referred to as a heat pipe reactor) is valued in advanced nuclear power concept design and passive safety system schemes due to its unique advantages. Compared with traditional reactor types, the heat pipe reactor adopts a heat pipe to conduct heat generated in a reactor core to a two-loop system. The fission energy generated in the heat pipe reactor is conducted to the evaporation end of a metal heat pipe arranged in the reactor core, and through the evaporation, natural circulation flow and condensation process of the working medium inside the heat pipe, heat is conducted from the reactor core to the hot end of the two-loop system. The heat pipe passive heat transfer is used as a means for heat extraction from the reactor core, and there is no loop system and rotating part in the reactor, the system is simplified, and the reactor core can be maintained free of maintenance.

[0003] In terms of power conversion form, carbon dioxide is considered to be one of the most promising energy conversion working media in nuclear power devices due to its characteristics of non-toxicity, large density, moderate critical pressure, abundant reserves and stable chemical properties. The supercritical carbon dioxide (sCO2) Brayton cycle using carbon dioxide as an energy conversion working medium is a single-phase cycle, and compared with a steam power cycle system, has the advantages of simple structure, high efficiency, small volume and low noise, and is a very promising nuclear power device energy conversion system. At present, there are two coupling modes of nuclear power devices and sCO2 Brayton cycles, one of which is to replace the traditional reactor core coolant (such as water, helium, etc.) and apply it to the one-loop system, which is called a direct cooling nuclear power device. In this mode, the nuclear power device and the coolant circulation system are integrated, and an intermediate heat exchanger is omitted, so that the nuclear reactor structure is more compact; the other is to be used as a new type of energy conversion system in the two-loop circulation system, such as a heat pipe reactor and an sCO2 Brayton cycle coupled nuclear power device.

[0004] The nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle has the characteristics of high safety, high power density, high reliability, low noise and good expansion capacity, and is suitable for special application scenarios such as deep sea. However, the nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle is more compact in arrangement and has more variable operating conditions, and there are greater internal parameter uncertainties and stronger external disturbances, which puts higher requirements on the control system design. Therefore, it is of great significance to study the control system and method of the nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle for the safe and stable operation of the nuclear power device. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a nuclear power device control system and method coupled with a heat pipe reactor and an sCO2 Brayton cycle to solve the control problem of a high-efficiency compact nuclear power device coupled with a heat pipe reactor and an sCO2 Brayton cycle, and to ensure the safe and stable operation of the system under the consideration of system operation restrictions.

[0006] The present application adopts the following technical solutions:

[0007] The nuclear power device control system coupled with the heat pipe reactor and the sCO2 Brayton cycle comprises an intermediate heat exchanger outlet temperature control system, a compressor inlet pressure control system, a rotating shaft speed control system and a compressor inlet temperature control system; the equipment comprises a control drum, a heat pipe reactor, an intermediate heat exchanger, a pressure tank, a regenerator, a turbine, a compressor, a generator and a cooler.

[0008] The intermediate heat exchanger connected with the heat pipe reactor has one end connected with the output end of the pressure tank and the other end connected with the input end of the pressure tank in sequence through the turbine, the regenerator, the cooler, the compressor and the regenerator; the turbine is connected with the compressor and the generator through the rotating shaft; the heat pipe reactor is connected with the intermediate heat exchanger outlet temperature control system through the nuclear power detector; the pressure tank is connected with the compressor inlet pressure control system through the first pressure sensor; the turbine, the compressor and the generator are connected with the rotating shaft speed control system through the first power sensor, the second power sensor and the third power sensor respectively; and the cooler output end is connected with the compressor inlet temperature control system through the second temperature sensor.

[0009] Specifically, a first temperature sensor is arranged on the pipeline between the intermediate heat exchanger and the turbine, and a nuclear power detector is arranged on the heat pipe reactor; the first temperature sensor and the nuclear power detector are both connected with the intermediate heat exchanger outlet temperature control system, and the intermediate heat exchanger outlet temperature control system drives the control drum to adjust the reactor reactivity.

[0010] Specifically, a first pressure sensor and a second pressure sensor are arranged on the pipeline between the surge tank and the cooler and the compressor; the first pressure sensor and the second pressure sensor are connected to a compressor inlet pressure control system, and the compressor inlet pressure control system adjusts the opening degrees of the pressure increasing valve and the pressure reducing valve on both sides of the surge tank.

[0011] Specifically, a first power sensor, a second power sensor, a third power sensor and a rotating speed sensor are arranged on the turbine, the compressor, the generator and the rotating shaft respectively; the first power sensor, the second power sensor, the third power sensor and the rotating speed sensor are all connected to a rotating shaft rotating speed control system, and the rotating shaft rotating speed control system adjusts the opening degree of the first control valve arranged between the compressor output end and the cooler input end.

[0012] Specifically, a second temperature sensor is arranged on the pipeline between the cooler and the compressor; the second temperature sensor is connected to a compressor inlet temperature control system, and the compressor inlet temperature control system adjusts the opening degree of the second control valve arranged at the seawater inlet end of the cooler.

[0013] Specifically, the intermediate heat exchanger outlet temperature control system adopts a cascade control structure, an outer ring is used to control the intermediate heat exchanger outlet temperature, and an inner ring is used to control the nuclear reactor power; the outer ring controller determines the required nuclear reactor power according to the deviation between the intermediate heat exchanger outlet temperature and the set value; then, the inner ring controller gives a control action signal according to the deviation between the nuclear reactor power and the reference value, and adjusts the nuclear reactor power to maintain the intermediate heat exchanger outlet temperature constant.

[0014] Specifically, the compressor inlet pressure control system calculates the required surge tank pressure according to the deviation between the compressor inlet pressure and the set value; and judges whether to increase or decrease the pressure according to the deviation between the required pressure and the actual pressure of the surge tank; when increasing the pressure, CO2 with specific parameters is filled into the surge tank, and when decreasing the pressure, part of the working medium is drained from the surge tank.

[0015] Specifically, the rotating shaft rotating speed control system adopts a cascade control structure, an outer ring controller takes the rotating shaft rotating speed as a control target, and an inner ring controller gives an action signal of the bypass valve arranged between the compressor and the cooler according to the difference between the turbine and the generator and the compressor power and the output of the outer ring controller, so as to maintain the rotating shaft rotating speed constant by adjusting the opening degree of the bypass valve.

[0016] Another technical scheme of the application is a control method of a nuclear power device control system coupled with a heat pipe reactor and an sCO2 Brayton cycle, comprising the following steps:

[0017] S1, the turbine, the compressor and the load are coaxially operated, and the rotating shaft rotating speed control system maintains the rotating shaft rotating speed constant by adjusting the bypass valve between the compressor and the cooler;

[0018] S2, the compressor inlet temperature control system controls the compressor inlet temperature by adjusting the seawater flow through the cooler, and the compressor inlet pressure control system controls the compressor inlet pressure by adjusting the steady pressure tank pressure;

[0019] S3, the intermediate heat exchanger outlet temperature control system controls the intermediate heat exchanger outlet temperature and the nuclear reactor power, respectively, and maintains the intermediate heat exchanger outlet temperature constant by adjusting the control drum introduced reactivity.

[0020] Specifically, the compressor inlet temperature control system maintains the compressor inlet temperature constant by adjusting the seawater flow through the cooler.

[0021] Compared with the prior art, the present application has at least the following beneficial effects:

[0022] The nuclear power device control system coupled with the heat pipe reactor and the sCO2 Brayton cycle has a rotating shaft speed control system designed from the system power quality angle, a compressor inlet temperature control system and an inlet pressure control system designed from the supercritical state of the working medium and the system efficiency, and an intermediate heat exchanger outlet temperature control system designed from the sensitivity of the turbine to the working medium inlet temperature.

[0023] Further, a first temperature sensor is arranged on the pipeline between the intermediate heat exchanger and the turbine for measuring the intermediate heat exchanger outlet temperature, and a nuclear power detector is arranged on the heat pipe reactor for measuring the heat pipe reactor power; the first temperature sensor and the nuclear power detector send the measurement values to the intermediate heat exchanger outlet temperature control system as the control input of the control system; and the output end of the control system is connected to the control drum.

[0024] Further, a first pressure sensor and a second pressure sensor are arranged on the pipeline between the steady pressure tank and the cooler and the compressor for measuring the steady pressure tank pressure and the compressor inlet pressure, respectively; the first pressure sensor and the second pressure sensor send the measurement values to the compressor inlet pressure control system as the control input of the control system; and the output of the control system is connected to the pressure increasing valve and the pressure reducing valve arranged on both sides of the steady pressure tank.

[0025] Further, a first power sensor, a second power sensor and a third power sensor are arranged on the turbine, the compressor and the generator, respectively, for measuring the turbine power, the compressor power and the generator power, respectively; a speed sensor is arranged on the rotating shaft for measuring the rotating shaft speed; the first power sensor, the second power sensor, the third power sensor and the speed sensor send the measurement values to the rotating shaft speed control system as the control input of the control system; and the output end of the control system is connected to the first control valve arranged between the compressor output end and the cooler input end.

[0026] Further, a second temperature sensor is arranged in the pipeline between the cooler and the compressor for measuring the compressor inlet temperature; the second temperature sensor sends the measured value to the compressor inlet temperature control system as the control input of the control system; the output end of the control system is connected to the second control valve arranged at the seawater inlet of the cooler.

[0027] The control method of the control system of the nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle considers the power supply quality, system efficiency, working medium state, and the like, and respectively formulates the control schemes of constant rotating shaft speed, constant intermediate heat exchanger outlet temperature, constant compressor inlet temperature, and constant compressor inlet pressure.

[0028] Further, in view of the fact that the turbine is sensitive to the working medium inlet temperature, the control scheme of constant intermediate heat exchanger outlet temperature is adopted, and a cascade intermediate heat exchanger outlet temperature control scheme is designed considering that the heat of the intermediate heat exchanger is derived from the heat pipe reactor; in the cascade control structure, the outer ring is used for controlling the intermediate heat exchanger outlet temperature, and the inner ring controls the nuclear reactor power, and the introduced reactivity of the control drum is adjusted to maintain the constant intermediate heat exchanger outlet temperature.

[0029] Further, in order to guarantee the system efficiency and ensure the supercritical state of the working medium at the compressor inlet, the control scheme of constant compressor inlet pressure is adopted; a pressure stabilizing tank is arranged between the regenerator and the intermediate heat exchanger, and the control of the compressor inlet pressure is realized by controlling the pressure of the pressure stabilizing tank; a pressure increasing valve and a pressure reducing valve are arranged before and after the pressure stabilizing tank, and the pressure in the pressure stabilizing tank is realized through the pressure increasing valve and the pressure reducing valve.

[0030] Further, the rotating shaft speed is related to the power supply quality, and in order to guarantee the power supply quality of the entire system, the control scheme of constant rotating shaft speed is adopted; the control scheme adopts a cascade control structure, the outer ring controller takes the rotating shaft speed as the control target, the inner ring controller gives the action signal of the bypass valve arranged between the compressor and the cooler according to the difference between the turbine power and the generator power and the compressor power and the output of the outer ring controller, so as to control the rotating shaft speed.

[0031] Further, in order to guarantee the supercritical state of the working medium at the compressor inlet, the control scheme of constant compressor inlet temperature is adopted; the compressor inlet temperature control is realized by adjusting the seawater flow through the cooler.

[0032] In summary, the control system and method of the nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle are convenient for engineering implementation, and are expected to have good economy and safety.

[0033] The technical scheme of the present application will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The control scheme diagram of the nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle;

[0035] Figure 2 The principle diagram of the rotating shaft rotating speed control system;

[0036] Figure 3 The principle diagram of the compressor inlet temperature control system;

[0037] Figure 4 The principle diagram of the compressor inlet pressure control system;

[0038] Figure 5 The principle diagram of the intermediate heat exchanger outlet temperature cascade control system;

[0039] Figure 6 The system dynamic response obtained under the control method of the present application, wherein (a) is the generator power, (b) is the turbine power, (c) is the rotating shaft rotating speed, (d) is the bypass valve opening, (e) is the intermediate heat exchanger outlet temperature, (f) is the reactor relative power, (g) is the compressor inlet temperature, and (h) is the compressor inlet pressure.

[0040] Wherein, 1. The intermediate heat exchanger outlet temperature control system; 2. The compressor inlet pressure control system; 3. The rotating shaft rotating speed control system; 4. The compressor inlet temperature control system; 5. The control drum; 6. The heat pipe reactor; 7. The intermediate heat exchanger; 8. The pressure stabilizing tank; 9. The regenerator; 10. The turbine; 11. The compressor; 12. The generator; and 13. The cooler. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0042] In the description of the application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "one side", "one end", "one edge" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0043] In the description of the application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] It should be understood that when used in the present specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0045] It should also be understood that the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0046] It should be further understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0047] In the drawings, various structural schematic diagrams according to the disclosed embodiments of the present application are shown. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clear expression, and certain details can be omitted. The shapes of various regions, layers and their relative size and positional relationship shown in the drawings are only exemplary, and in actuality there can be deviations due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes and relative positions according to actual needs.

[0048] Referring to Figure 1 The application provides a nuclear power device control system coupled with a heat pipe reactor and an sCO2 Brayton cycle, comprising four control systems, namely a rotating shaft rotating speed control system 3, a compressor inlet temperature control system 4, a compressor inlet pressure control system 2 and an intermediate heat exchanger outlet temperature control system 1.

[0049] The output end of the pressure stabilizing tank 8 is connected to the input end of the turbine 10 through the intermediate heat exchanger 7, a first temperature sensor is arranged on the connecting pipeline between the intermediate heat exchanger 7 and the turbine 10, the intermediate heat exchanger 7 is connected to the heat pipe reactor 6 through a heat pipe, a nuclear power detector is arranged on the side of the heat pipe reactor 6, the output end of the turbine 10 is connected to the input end of the compressor 11 through the regenerator 9 and the cooler 13, a second temperature sensor and a second pressure sensor are sequentially arranged on the connecting pipeline between the cooler 13 and the compressor 11, the output end of the compressor 11 is connected to the input end of the pressure stabilizing tank 8 through the regenerator 9, and the pressure stabilizing tank 8 is arranged with a first pressure sensor; the turbine 10 is arranged with a first power sensor, the compressor 11 is arranged with a second power sensor, a generator 12 is arranged with a third power sensor, and the rotating shaft is arranged with a rotating speed sensor.

[0050] The nuclear power detector, the first temperature sensor and the intermediate heat exchanger outlet temperature control system 1 are connected, the control end of the intermediate heat exchanger outlet temperature control system 1 is connected to the control drum 5, and the control drum 5 is connected to the heat pipe reactor 6.

[0051] The first pressure sensor and the second pressure sensor are connected to the compressor inlet pressure control system 2, and the control end of the compressor inlet pressure control system 2 is connected to the pressure increasing valve and the pressure reducing valve on the two sides of the pressure stabilizing tank 8.

[0052] The first power sensor, the second power sensor, the third power sensor and the rotating speed sensor are connected to the rotating shaft rotating speed control system 3, the control end of the rotating shaft rotating speed control system 3 is connected to a first control valve, one end of the first control valve is connected to the compressor 11 and the regenerator 9, and the other end is connected to the regenerator 9 and the cooler 13; the second temperature sensor is connected to the compressor inlet temperature control system 4, and the control end of the compressor inlet temperature control system 4 is connected to a second control valve, one end of the second control valve is connected to seawater, and the other end is connected to the cooler 13 through a pipeline.

[0053] Referring to Figure 2 The turbine 10, the compressor 11 and the load (the generator 12) operate coaxially, in order to ensure the power supply quality of the system, it is necessary to ensure that the rotating speed of the rotating shaft is constant, the rotating shaft rotating speed control system 3 is designed, and the rotating shaft rotating speed control system 3 is a cascade control system.

[0054] The rotating shaft rotating speed set value and the rotating speed sensor collected rotating shaft rotating speed are compared in the first comparator, and the difference value signal is sent to the second outer loop controller; the output of the second outer loop controller is compared with the power of the generator 12 in the second comparator, and the difference value signal obtained is subjected to algebraic operation with the power of the compressor 11 and the power of the turbine 10 and is sent to the second inner loop controller, and the output of the second inner loop controller is sent to the first control valve.

[0055] Referring to Figure 3 In order to ensure that the temperature and density of the working medium at the compressor inlet are in the design state (supercritical state), the compressor inlet temperature control system 4 is designed.

[0056] The cooler outlet temperature (compressor inlet temperature) set value is compared with the cooler outlet temperature measured by the second temperature sensor in the first comparator, and the difference value signal is sent to the first controller; the output signal of the first controller is sent to the second control valve.

[0057] Referring to Figure 4 In order to ensure that the temperature and density of the working medium at the compressor inlet are in the design state (supercritical state) and the system efficiency, the compressor inlet pressure control system 2 is designed.

[0058] The compressor inlet pressure set value is compared with the compressor inlet pressure measured by the second pressure sensor in the fifth comparator, and the difference value signal is sent to the second controller; the output of the second controller is compared with the steady pressure tank pressure measured by the first pressure sensor in the sixth comparator, and the difference value signal is sent to the pressure increasing valve and the pressure reducing valve.

[0059] Referring to Figure 5 The intermediate heat exchanger outlet temperature control system 1 is designed by adopting the operation control scheme of constant intermediate heat exchanger outlet working medium temperature.

[0060] The intermediate heat exchanger outlet temperature set value is compared with the intermediate heat exchanger outlet temperature measured by the first temperature sensor in the seventh comparator, and the difference value signal is sent to the first outer loop controller; the output of the first outer loop controller is compared with the heat pipe reactor power measured by the nuclear power detector in the eighth comparator, and the difference value is sent to the first inner loop controller; the output of the first inner loop controller is converted into the control drum introduced reactivity by the control drum driving mechanism and the differential value, and is input into the heat pipe reactor.

[0061] The application discloses a control method of a nuclear power device coupled with a heat pipe stack and an sCO2 Brayton cycle, a rotating shaft rotating speed control system is designed to maintain the rotating shaft rotating speed at a constant value to ensure the power supply quality of the whole system, a compressor inlet temperature and pressure control system is designed to ensure that the temperature and density of the working medium at the compressor inlet are in a design state (supercritical state), and a cascade control system taking the intermediate heat exchanger outlet temperature as an outer ring controlled variable and the nuclear reactor power as an inner ring controlled variable is designed to maintain the intermediate heat exchanger outlet temperature constant.

[0062] S1, the turbine 10, the compressor 11 and the load (the generator 12) are coaxially arranged, the rotating shaft rotating speed control system is designed to maintain the rotating shaft rotating speed constant to ensure the power supply quality of the system, and the bypass valve between the compressor and the cooler is adjusted to maintain the rotating shaft rotating speed constant.

[0063] According to the rotating shaft model, when the system is in a steady state, the turbine power is equal to the sum of the generator power and the compressor power; when the system is in a load reduction (load increase) state, for the rotating shaft, the driving torque is greater (smaller) than the resistance torque, the rotating shaft rotating speed is increased (decreased), and a deviation between the rotating shaft rotating speed and a set value exists. At this time, the second outer ring controller gives an output signal according to the rotating speed deviation signal.

[0064] If the system load changes, the turbine power, the compressor power and the generator power will lose balance, that is, the algebraic sum is not equal to 0.

[0065] The second inner ring controller gives a bypass valve action signal according to the output of the second outer ring controller and the power difference between the turbine power, the compressor power and the generator power.

[0066] Finally, when the turbine power, the compressor power and the generator power reach balance, the rotating shaft rotating speed is maintained at a constant value.

[0067] When the system is in a load increase or load reduction state, the energy balance will be temporarily broken; for the rotating shaft rotating speed control system, the difference between the turbine power, the compressor power and the generator power is introduced into the control system to play a feedforward role, which is beneficial to accelerate the response of the control system.

[0068] S2, the compressor inlet temperature and pressure control scheme is designed to ensure that the temperature and density of the working medium at the compressor inlet are in a design state (supercritical state) and the system efficiency.

[0069] The compressor inlet temperature is controlled by adjusting the seawater flow through the cooler 13, and the inlet pressure is controlled by adjusting the pressure of the pressure stabilizing tank arranged in the system.

[0070] The specific control logic of the compressor inlet pressure is as follows:

[0071] First, according to the deviation between the compressor inlet pressure and its set value, the required steady tank pressure is calculated; then according to the deviation between the steady tank required pressure and the actual pressure, it is judged whether the pressure needs to be raised or lowered;

[0072] When the steady tank pressure needs to be lowered, the pressure reducing valve is opened, and a part of the working medium is led out from the steady tank to lower the pressure in the steady tank;

[0073] When the steady tank pressure needs to be raised, the pressure increasing valve is opened, and the CO2 of a specific parameter is filled into the steady tank to increase the pressure in the steady tank.

[0074] S3, in order to maintain the outlet temperature of the intermediate heat exchanger constant, the outlet temperature of the intermediate heat exchanger is designed as a cascade control system, the outer ring is used to control the outlet temperature of the intermediate heat exchanger, and the inner ring controls the nuclear reactor power, and the reactivity introduced by the control drum is adjusted to maintain the outlet temperature of the intermediate heat exchanger constant.

[0075] The specific control logic is as follows:

[0076] First, the first outer ring controller gives the required nuclear reactor power according to the deviation between the outlet temperature of the intermediate heat exchanger and its set value;

[0077] Then, the first inner ring controller gives the control drum action signal according to the deviation between the nuclear reactor power and its reference value, introduces the reactivity into the heat pipe reactor 5, adjusts the nuclear reactor power, so as to realize the control purpose of maintaining the outlet temperature of the heat exchanger constant.

[0078] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0079] Please refer to Figure 6 When the load (referring to the generator power) of the nuclear power device coupled with the heat pipe reactor and the sCO2 Brayton cycle is stepped down from 100% FP (Full Power) to 90% FP, and then stepped up to 100% FP after stable operation for a period of time, the dynamic response curve of the key parameters of the system obtained by using the control system and method proposed in the present application is shown in the figure;

[0080] When the load decreases, the rotating shaft speed will increase, under the action of the rotating shaft speed control system, the bypass valve opening degree increases, a part of the working medium flows into the cooler from the compressor outlet through the bypass valve, resulting in the decrease of the turbine power, so that the rotating shaft speed returns to the set value after a short rise.

[0081] At the same time, the increase of the bypass valve opening degree will lead to the decrease of the working medium flow in the intermediate heat exchanger, and the temperature at the outlet of the intermediate heat exchanger will increase before the heat changes.

[0082] Under the action of the intermediate heat exchanger outlet temperature control system, if the temperature at the outlet of the intermediate heat exchanger increases, the nuclear reactor power demand load calculated by the outer ring controller will decrease, and the control drum will act to introduce negative reactivity into the reactor, resulting in the decrease of the nuclear reactor power.

[0083] And the compressor inlet temperature and pressure are also maintained constant under the action of the corresponding control system. When the system increases the load, the dynamic change trend of the key parameters is just the opposite of the decrease of the load.

[0084] In summary, the control method of the nuclear power device coupled by the heat pipe reactor and the sCO2 Brayton cycle can effectively control the key parameters of the system at the set value, and the feasibility of the control system and method is demonstrated.

[0085] The above content is only for illustrating the technical idea of the present application, and cannot limit the protection scope of the present application, and any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A control system for a nuclear power plant coupled with a heat pipe reactor and a sCO2 Brayton cycle, characterized in that, The equipment includes an intermediate heat exchanger outlet temperature control system (1), a compressor inlet pressure control system (2), a rotating shaft speed control system (3), and a compressor inlet temperature control system (4); the equipment includes a control drum (5), a heat pipe reactor (6), an intermediate heat exchanger (7), a pressure tank (8), a regenerator (9), a turbine (10), a compressor (11), a generator (12), and a cooler (13). An intermediate heat exchanger (7) is connected to the heat pipe reactor (6). One end of the intermediate heat exchanger (7) is connected to the output end of the pressure tank (8), and the other end is connected to the input end of the pressure tank (8) via the turbine (10), regenerator (9), cooler (13), compressor (11) and regenerator (9) in sequence. The turbine (10) is connected to the compressor (11) and generator (12) via a rotating shaft. The heat pipe reactor (6) is connected to the intermediate heat exchanger outlet temperature control system (1) via a nuclear power detector. The control end of the intermediate heat exchanger outlet temperature control system (1) is connected to the heat pipe reactor (6) via a control drum (5). The pressure tank (8) is connected to the compressor inlet pressure control system (2) via a first pressure sensor. The turbine (10), compressor (11), and generator (12) are connected to the rotating shaft speed control system (3) via a first power sensor, a second power sensor, and a third power sensor, respectively. The output end of the cooler (13) is connected to the compressor inlet temperature control system (4) via a second temperature sensor. The rotating shaft speed control system (3) adopts a cascade control structure. The outer loop controller takes the rotating shaft speed as the control target. The inner loop controller, based on the power difference between the turbine (10), generator (12), and compressor (11) and the output of the outer loop controller, gives the action signal of the bypass valve configured between the compressor (11) and cooler (13). The rotating shaft speed is kept constant by adjusting the opening of the bypass valve.

2. The nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 1, characterized in that, A first temperature sensor is installed on the pipeline between the intermediate heat exchanger (7) and the turbine (10), and a nuclear power detector is installed in the heat pipe reactor (6); the first temperature sensor and the nuclear power detector are both connected to the intermediate heat exchanger outlet temperature control system (1), and the intermediate heat exchanger outlet temperature control system (1) drives the control drum (5) to adjust the core reactivity.

3. The nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 1, characterized in that, A first pressure sensor and a second pressure sensor are installed on the pipeline between the pressure stabilizing tank (8), the cooler (13), and the compressor (11); the first pressure sensor and the second pressure sensor are connected to the compressor inlet pressure control system (2), and the compressor inlet pressure control system (2) adjusts the opening of the pressure boosting valve and the pressure reducing valve on both sides of the pressure stabilizing tank (8).

4. The nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 1, characterized in that, A first power sensor, a second power sensor, a third power sensor, and a speed sensor are respectively installed on the turbine (10), the compressor (11), the generator (12), and the rotating shaft. The first power sensor, the second power sensor, the third power sensor, and the speed sensor are all connected to the rotating shaft speed control system (3). The rotating shaft speed control system (3) adjusts the opening of the first control valve arranged between the output end of the compressor (11) and the input end of the cooler (13).

5. The nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 1, characterized in that, A second temperature sensor is installed on the pipeline between the cooler (13) and the compressor (11); the second temperature sensor is connected to the compressor inlet temperature control system (4), and the compressor inlet temperature control system (4) adjusts the opening of the second control valve arranged at the seawater inlet end of the cooler (13).

6. The nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 1, characterized in that, The intermediate heat exchanger outlet temperature control system (1) adopts a cascade control structure. The outer loop is used to control the intermediate heat exchanger outlet temperature, and the inner loop is used to control the nuclear reactor power. The outer loop controller determines the required nuclear reactor power based on the deviation between the intermediate heat exchanger outlet temperature and the set value. Then, the inner loop controller gives the control drum action signal based on the deviation between the nuclear reactor power and the reference value to adjust the nuclear reactor power so that the intermediate heat exchanger outlet temperature is kept constant.

7. The nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 1, characterized in that, The compressor inlet pressure control system (2) calculates the required pressure of the pressure stabilizing tank based on the deviation between the compressor inlet pressure and the set value; then it determines whether to increase or decrease the pressure based on the deviation between the required pressure of the pressure stabilizing tank and the actual pressure; when increasing the pressure, CO2 with specific parameters is charged into the pressure stabilizing tank (8); when decreasing the pressure, a portion of the working fluid is drained from the pressure stabilizing tank (8).

8. The method of operating the control system of a nuclear power plant coupled with a heat pipe reactor and a sCO2 Brayton cycle according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. The turbine and compressor operate coaxially with the load. The rotating shaft speed control system maintains a constant rotating shaft speed by adjusting the bypass valve between the compressor and the cooler. S2. The compressor inlet temperature control system controls the compressor inlet temperature by adjusting the seawater flow rate through the cooler, and the compressor inlet pressure control system controls the compressor inlet pressure by adjusting the pressure stabilizing tank. S3, the intermediate heat exchanger outlet temperature control system, controls the intermediate heat exchanger outlet temperature and the nuclear reactor power respectively, and maintains the intermediate heat exchanger outlet temperature constant by adjusting the reactivity introduced by the control drum.

9. The operating method of the nuclear power plant control system coupled with a heat pipe reactor and a sCO2 Brayton cycle according to claim 8, characterized in that, The compressor inlet temperature control system maintains a constant compressor inlet temperature by adjusting the seawater flow rate through the cooler.

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