Sodium-cooled fast reactor main feed water flow control system

Abstract

The invention particularly relates to a sodium-cooled fast reactor main feed water flow control system, which comprises a control mode switching module used for carrying out undisturbed switching on a single-impulse control mode and a three-impulse control mode of main feed water flow under an automatic control mode of a main feed water regulating valve; the three-impulse PID is used for executing a main feed water flow three-impulse control mode; the single-impulse PID is used for executing a main feed water flow single-impulse control mode; a large valve and a small valve of the main water supply regulating valve are fitted into the main water supply regulating valve through a curve. According to the invention, the full-automatic control of the main feed water flow of the whole power platform is realized while the control of the main feed water flow meets the unit requirements, and the main feed water flow is ensured to have a quick-response adjusting capability under each transient working condition.

Description

Technical Field

[0001] The invention relates to the technical field of main feed water flow control for sodium-cooled fast reactors, in particular to a main feed water flow control system for sodium-cooled fast reactors. Background Art

[0002] In a sodium-cooled fast reactor, the steam generator uses a direct current steam generator. The direct current steam generator has a small feed water volume. The movement of the vaporization boundary line causes changes in the water vapor space and causes pipeline vibration. At the same time, the main feed water system also has the important function of controlling the sodium temperature at the steam generator outlet. Therefore, the main feed water flow regulation is required to have extremely high control accuracy, which increases the difficulty of realizing automatic control of the flow of the main feed water system.

[0003] Sodium-cooled fast reactors operating at power levels below 28% need to complete a series of important nodes, including water-steam conversion, steam-water conversion, turbine run-up and grid connection. These nodes require high precision in feedwater control. Therefore, the feedwater flow is manually controlled at 28% of the power level of sodium-cooled fast reactors, which greatly increases the workload of operators and brings instability to the unit. Summary of the invention

[0004] The purpose of the present invention is to provide a main feed water flow control system for a sodium-cooled fast reactor, which ensures that the main feed water flow control meets the requirements of the unit and realizes full-automatic control of the main feed water flow of the entire power platform, and ensures that the main feed water flow has a rapid response regulation capability under various transient operating conditions.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A main feed water flow control system for a sodium-cooled fast reactor, comprising:

[0007] A control mode switching module is used to perform disturbance-free switching between the single-impulse control mode and the three-impulse control mode of the main water supply flow in the automatic control mode of the main water supply regulating valve;

[0008] The three-impulse PID is used to execute the three-impulse control mode of the main water supply flow rate. In the three-impulse control mode of the main water supply flow rate, the three-impulse PID outputs the main water supply regulating valve opening signal to the main water supply regulating valve, and the main water supply regulating valve adjusts the opening according to the main water supply regulating valve opening signal output by the three-impulse PID, thereby controlling the main water supply flow rate.

[0009] Single impulse PID is used to execute the main water supply flow single impulse control mode; in the main water supply flow single impulse control mode, the single impulse PID outputs the main water supply regulating valve opening signal to the main water supply regulating valve, and the main water supply regulating valve adjusts the opening according to the main water supply regulating valve opening signal output by the single impulse PID, thereby controlling the main water supply flow;

[0010] The large valve and small valve of the main water supply regulating valve are formed into the main water supply regulating valve through curve fitting.

[0011] As one of the feasible methods, single impulse PID single impulse controls the main water flow, including the following steps:

[0012] Receive the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value; calculate the main feed water flow set value according to the difference between the evaporator outlet sodium temperature and the steam valve outlet sodium temperature set value;

[0013] According to the main feed water flow setting value, calculate the main feed water regulating valve opening setting value;

[0014] According to the main water supply regulating valve opening setting value, a main water supply regulating valve opening signal is generated and sent to the main water supply regulating valve;

[0015] The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal.

[0016] As one of the possible implementations, the three-impulse PID includes:

[0017] The three-impulse main adjustment PID is used to receive the evaporator outlet sodium temperature, the evaporator outlet sodium temperature set value and the main feed water flow feedforward value; calculate the first set value of the main feed water flow according to the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value; add the main feed water flow feedforward value to the first set value of the main feed water flow to obtain the second set value of the main feed water flow;

[0018] The three-impulse auxiliary PID is used to receive the second set value of the main water supply flow and the measured value of the main water supply flow; calculate the main water supply regulating valve opening set value according to the difference between the second set value of the main water supply flow and the measured value of the main water supply flow; generate the main water supply regulating valve opening signal according to the main water supply regulating valve opening set value and send it to the main water supply regulating valve;

[0019] The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal.

[0020] As one of the feasible ways, the main feedwater flow rate feedforward value is calculated according to the following formula based on the reactor secondary loop sodium pump speed, superheater inlet sodium temperature and evaporator outlet sodium temperature setting value:

[0021] Main feed water flow rate feedforward value = ((reactor secondary circuit sodium pump speed / 5.6) × ((superheater inlet sodium temperature - evaporator outlet sodium temperature setting value) / 197)) × (single loop main feed water flow rate during normal operation under reactor full power condition / 100);

[0022] Among them, the unit of the main feed water flow feedforward value is t / h; the single-loop main feed water flow during normal operation under full power conditions is t / h; the unit of the reactor secondary loop sodium pump speed is rpm; the unit of the superheater inlet sodium temperature and the evaporator outlet sodium temperature setting values ​​are both ℃.

[0023] As one of the achievable methods, in the single-impulse control mode, the three-impulse sub-regulation PID tracks the output value of the single-impulse PID. When the single-impulse control mode is switched to the three-impulse control mode, the output value of the three-impulse sub-regulation PID starts from its tracking value.

[0024] In the three-impulse control mode, the single-impulse PID tracks the output value of the three-impulse sub-regulation PID. When the three-impulse control mode is switched to the single-impulse control mode, the output value of the single-impulse PID starts from its tracking value.

[0025] As one of the feasible ways, the control mode switching module is used to automatically or manually switch the main water supply flow control mode to the three-impulse control mode or the single-impulse control mode under the automatic control mode of the main water supply regulating valve; the manual switching has a higher priority than the automatic switching.

[0026] As one of the feasible ways, in the low power stage of the sodium-cooled fast reactor, the control mode switching module automatically switches to the single-impulse control mode; in the high power stage of the sodium-cooled fast reactor, the control mode switching module automatically switches to the three-impulse control mode.

[0027] As one of the achievable ways, the low power stage of the sodium-cooled fast reactor reactor is when the power of the sodium-cooled fast reactor reactor is below 28% of the full power; and the high power stage of the sodium-cooled fast reactor reactor is when the power of the sodium-cooled fast reactor reactor exceeds 28% of the full power.

[0028] As one of the feasible ways, the main feed water flow control system of the sodium-cooled fast reactor also includes:

[0029] The manual-automatic switching module is used to switch the control mode of the main water supply regulating valve, large valve and small valve to manual control mode or automatic control mode without disturbance.

[0030] As one of the achievable ways, in the manual control mode of the main water supply regulating valve, the three-impulse auxiliary regulation PID generates a main water supply regulating valve opening signal according to the manually input main water supply regulating valve opening setting value and outputs it to the main water supply regulating valve, and the main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal output by the three-impulse auxiliary regulation PID;

[0031] In the manual control mode of the main water supply regulating valve, the three-impulse auxiliary regulation PID tracks its own output value. When the manual control of the main water supply regulating valve is switched to the automatic control mode, the opening of the main water supply regulating valve is adjusted from the tracking value of the three-impulse auxiliary regulation PID.

[0032] As one of the achievable methods, in the large valve manual control mode, the three-impulse auxiliary regulation PID generates a large valve opening signal according to the manually input large valve opening setting value and outputs it to the large valve, and the large valve adjusts its opening according to the large valve opening signal output by the three-impulse auxiliary regulation PID;

[0033] In the manual control mode of the large valve, the large valve tracks its current opening, and the three-impulse auxiliary PID tracks the opening value of the large valve calculated by the inverse function of the fitting curve based on the current opening of the large valve;

[0034] When the large valve manual control mode is switched to the automatic control mode, the opening of the large valve is adjusted from the tracking value of the three-impulse auxiliary regulation PID.

[0035] As one of the achievable methods, in the small valve manual control mode, the three-impulse auxiliary regulation PID generates a small valve opening signal according to the manually input small valve opening setting value and outputs it to the small valve, and the small valve adjusts its opening according to the small valve opening signal output by the three-impulse auxiliary regulation PID;

[0036] In the manual control mode of the small valve, the small valve tracks its current opening, and the three-impulse auxiliary PID tracks the opening value of the small valve calculated by the inverse function of the fitting curve based on the current opening of the small valve;

[0037] When the manual control mode of the small valve is switched to the automatic control mode, the opening of the large valve is adjusted from the tracking value of the three-impulse auxiliary regulation PID.

[0038] As one of the feasible methods, when one of the large valve and the small valve is in manual control mode and the other is in automatic control mode, the switching from manual control mode to automatic control mode needs to meet the following conditions: the opening of the small valve is less than 87.5% and the opening of the large valve is less than 1%, or the opening of the small valve is greater than 99% and the opening of the large valve is greater than 20%.

[0039] Beneficial technical effects of the present invention:

[0040] The sodium-cooled fast reactor main feed water flow control system of the present invention realizes full-process automatic control of the main feed water flow throughout the power platform and has the ability to quickly respond to regulation in various transient operating conditions. Specifically, the large valve and the small valve of the main feed water regulating valve are controlled by fitting the curve to form the main feed water regulating valve, which is convenient for overall control of the large valve and the small valve of the main feed water regulating valve, and provides a prerequisite for full-process automatic control of the main feed water flow throughout the power platform. By adopting a single-impulse control mode for the main feed water flow in the low-power stage of the sodium-cooled fast reactor reactor and a three-impulse control mode for the main feed water flow in the high-power stage of the sodium-cooled fast reactor reactor, the accuracy of the main feed water flow control of the entire power platform is improved. By adopting a main feed water flow feedforward control mode, it is ensured that the main feed water flow has the ability to quickly respond to regulation in various transient operating conditions, and the anti-interference performance of the main feed water flow control is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a schematic structural view of an embodiment of a main feed water flow control system for a sodium-cooled fast reactor. DETAILED DESCRIPTION

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0043] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0044] The technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0045] In a sodium-cooled fast reactor, the main feed water regulating valve consists of a large valve and a small valve, which provides water to the evaporator to maintain the sodium temperature at the evaporator outlet stable. The existing main feed water flow control system for sodium-cooled fast reactors includes:

[0046] The main adjustment PID of the large valve is used to calculate the sodium-water flow ratio set value based on the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value;

[0047] The auxiliary PID of the large valve is used to calculate the large valve opening setting value according to the difference between the sodium-water flow ratio and the sodium-water flow setting value; and control the large valve opening according to the large valve opening setting value;

[0048] The main adjustment PID of the small valve is used to calculate the set value of the sodium-water flow ratio according to the difference between the sodium temperature at the evaporator outlet and the set value of the sodium temperature at the evaporator outlet;

[0049] The sub-regulation PID of the small valve is used to calculate the small valve opening setting value according to the difference between the sodium-water flow ratio and the sodium-water flow setting value; and to control the large valve opening according to the small valve opening setting value.

[0050] In the existing sodium-cooled fast reactor main feed water flow control system, the control logic of the large valve and the small valve are consistent, and the automatic adjustment function of the sodium-cooled fast reactor reactor power below 28% of the full power cannot be realized. In addition, manual switching is required during the switching process between the large valve and the small valve, which may cause fluctuations in the main feed water flow when the large valve and the small valve are switched.

[0051] See also Figure 1 This embodiment provides a sodium-cooled fast reactor main feed water flow control system, including:

[0052] A control mode switching module is used to perform disturbance-free switching between the single-impulse control mode and the three-impulse control mode of the main water supply flow in the automatic control mode of the main water supply regulating valve;

[0053] The three-impulse PID is used to execute the three-impulse control mode of the main water supply flow rate. In the three-impulse control mode of the main water supply flow rate, the three-impulse PID outputs the main water supply regulating valve opening signal to the main water supply regulating valve, and the main water supply regulating valve adjusts the opening according to the main water supply regulating valve opening signal output by the three-impulse PID, thereby controlling the main water supply flow rate.

[0054] Single impulse PID is used to execute the main water supply flow single impulse control mode; in the main water supply flow single impulse control mode, the single impulse PID outputs the main water supply regulating valve opening signal to the main water supply regulating valve, and the main water supply regulating valve adjusts the opening according to the main water supply regulating valve opening signal output by the single impulse PID, thereby controlling the main water supply flow;

[0055] The large valve and small valve of the main water supply regulating valve are formed into the main water supply regulating valve through curve fitting.

[0056] In this embodiment, as one of the achievable methods, single impulse PID single impulse controls the main water supply flow, including the following steps:

[0057] Receive the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value; calculate the main feed water flow set value according to the difference between the evaporator outlet sodium temperature and the steam valve outlet sodium temperature set value;

[0058] According to the main feed water flow setting value, calculate the main feed water regulating valve opening setting value;

[0059] According to the main water supply regulating valve opening setting value, a main water supply regulating valve opening signal is generated and sent to the main water supply regulating valve;

[0060] The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal.

[0061] In this embodiment, as one of the achievable methods, the three-impulse PID includes:

[0062] The three-impulse main adjustment PID is used to receive the evaporator outlet sodium temperature, the evaporator outlet sodium temperature set value and the main feed water flow feedforward value; calculate the first set value of the main feed water flow according to the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value; add the main feed water flow feedforward value to the first set value of the main feed water flow to obtain the second set value of the main feed water flow;

[0063] The three-impulse auxiliary PID is used to receive the second set value of the main water supply flow and the measured value of the main water supply flow; calculate the main water supply regulating valve opening set value according to the difference between the second set value of the main water supply flow and the measured value of the main water supply flow; generate the main water supply regulating valve opening signal according to the main water supply regulating valve opening set value and send it to the main water supply regulating valve;

[0064] The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal.

[0065] The sodium temperature at the evaporator outlet is affected by three parameters: the speed of the reactor secondary circuit sodium pump, the superheater inlet sodium temperature, and the evaporator outlet sodium temperature setting value; any change in the three parameters will cause a change in the evaporator outlet sodium temperature, so the change in the evaporator outlet sodium temperature can be predicted by the change of the three parameters. In this embodiment, as one of the achievable methods, the main feed water flow feedforward value is calculated according to the following formula based on the reactor secondary circuit sodium pump speed, the superheater inlet sodium temperature, and the evaporator outlet sodium temperature setting value:

[0066] Main feed water flow rate feedforward value = ((reactor secondary circuit sodium pump speed / 5.6) × ((superheater inlet sodium temperature - evaporator outlet sodium temperature setting value) / 197)) × (single loop main feed water flow rate during normal operation under reactor full power condition / 100);

[0067] Among them, the unit of the main feed water flow feedforward value is t / h; the single-loop main feed water flow during normal operation under the reactor full power condition is t / h; the unit of the reactor secondary circuit sodium pump speed is rpm; the units of the superheater inlet sodium temperature and the evaporator outlet sodium temperature setting values ​​are both ℃; the reactor secondary circuit sodium pump speed / 5.6 is the percentage of the full speed of the sodium pump during normal operation under the reactor full power condition; (superheater inlet sodium temperature-evaporator outlet sodium temperature setting value) / 197 is the percentage of the temperature difference between the superheater inlet sodium temperature and the evaporator outlet sodium temperature during normal operation under full power conditions.

[0068] In this embodiment, as one of the achievable methods, the single-loop main feed water flow rate is 1140 t / s when the reactor is operating normally at full power; the sodium temperature setting value at the evaporator outlet is 308°C; the secondary circuit sodium pump speed is 560 rpm when the reactor is operating normally at full power; the difference between the superheater inlet sodium temperature and the evaporator outlet sodium temperature is 197°C when the reactor is operating normally at full power.

[0069] The main feed water flow feedforward value is equal to the normally designed main feed water flow when the reactor is operating normally at full power. However, when there is a sudden drop in the sodium pump speed and a sudden drop in the sodium temperature at the superheater inlet, the main feed water flow feedforward will also be reduced at the same time. This ensures that the main feed water flow can be adjusted in advance through feedforward when there is a sudden change in the sodium pump speed and a sudden change in the sodium temperature at the superheater inlet.

[0070] The most important function of the main feedwater flow is to control the sodium temperature at the evaporator outlet to maintain stability. Any parameter that affects the change of the sodium temperature at the evaporator outlet will affect the change of the main feedwater flow. Therefore, the main feedwater flow calculated by the various parameters that affect the change of the sodium temperature at the evaporator outlet can be used as a feedforward to predict and adjust the main feedwater flow in advance, greatly improving the response speed of the main feedwater flow regulation. Under transient conditions such as shutdown and sodium pump speed changes, the change of the sodium temperature at the evaporator outlet can be predicted, and then the change of the main feedwater flow feedforward value can be predicted. The main feedwater flow is adjusted in advance through feedforward to ensure that the main feedwater flow has a fast response regulation capability under various transient conditions.

[0071] In the present embodiment, as one of the feasible methods, in the single-impulse control mode, the three-impulse sub-regulation PID tracks the output value of the single-impulse PID, and when the single-impulse control mode is switched to the three-impulse control mode, the output value of the three-impulse sub-regulation PID starts from its tracking value, and the opening of the main water supply regulating valve will not change suddenly, thereby realizing bypass-free switching; in the three-impulse control mode, the single-impulse PID tracks the output value of the three-impulse sub-regulation PID, and when the three-impulse control mode is switched to the single-impulse control mode, the output value of the single-impulse PID starts from its tracking value, and the opening of the main water supply regulating valve will not change suddenly, thereby realizing bypass-free switching.

[0072] In this embodiment, as one of the feasible methods, the control mode switching module is used to automatically or manually switch the main water supply flow control mode to a three-impulse control mode or a single-impulse control mode under the automatic control mode of the main water supply regulating valve; manual switching has a higher priority than automatic switching.

[0073] In this embodiment, as one of the feasible ways, in the low power stage of the sodium-cooled fast reactor, the control mode switching module automatically switches to the single-impulse control mode; in the high power stage of the sodium-cooled fast reactor, the control mode switching module automatically switches to the three-impulse control mode.

[0074] In this embodiment, as one of the achievable methods, the low power stage of the sodium-cooled fast reactor reactor is when the power of the sodium-cooled fast reactor reactor is below 28% of the full power; and the high power stage of the sodium-cooled fast reactor reactor is when the power of the sodium-cooled fast reactor reactor exceeds 28% of the full power.

[0075] The ultimate control target of main feed water flow regulation is to maintain the sodium temperature at the evaporator outlet at the set value. In order to realize the automatic control of the main feed water flow of the entire power platform, the large valve and the small valve of the main feed water regulating valve are combined into the main feed water regulating valve through curve fitting. The opening of the main feed water regulating valve is adjusted according to the PID output. In terms of control method, the control of two valves is changed to the control of one valve, which greatly reduces the complexity of the control system and provides the prerequisite for realizing the full process automatic control of the main feed water flow of the entire power platform.

[0076] In the low power stage of sodium-cooled fast reactor, the main feed water flow is small, and the parameters affecting the change of sodium temperature at the evaporator outlet have little effect on the main feed water flow. Therefore, in the low power stage of sodium-cooled fast reactor, the main feed water flow is controlled by a single impulse. In the high power stage of sodium-cooled fast reactor, the main feed water flow is large, and the parameters affecting the change of sodium temperature at the evaporator outlet have a large effect on the main feed water flow. Therefore, in the low power stage of sodium-cooled fast reactor, the main feed water flow is controlled by three impulses.

[0077] By adopting a single-impulse control method for the main feed water flow in the low-power stage of the sodium-cooled fast reactor reactor and a three-impulse control method for the main feed water flow in the high-power stage of the sodium-cooled fast reactor reactor, the accuracy of the main feed water flow control of the entire power platform is improved; through the main feed water flow feedforward control method, the main feed water flow is guaranteed to have a fast-response regulation capability in various transient operating conditions, thereby improving the anti-interference ability of the main feed water flow control.

[0078] In this embodiment, as one of the feasible ways, the main feed water flow control system of the sodium-cooled fast reactor further includes: a manual-automatic switching module for non-disturbance switching of the control mode of the main feed water regulating valve, the large valve and the small valve to the manual control mode or the automatic control mode.

[0079] In the present embodiment, as one of the feasible methods, in the manual control mode of the main water supply regulating valve, the three-impulse sub-regulation PID generates a main water supply regulating valve opening signal according to the manually input main water supply regulating valve opening setting value, and outputs it to the main water supply regulating valve, and the main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal output by the three-impulse sub-regulation PID; in the manual control mode of the main water supply regulating valve, the three-impulse sub-regulation PID tracks its own output value, and when the manual control of the main water supply regulating valve is switched to the automatic control mode, the opening of the main water supply regulating valve is adjusted from the tracking value of the three-impulse sub-regulation PID, which will not cause a sudden change in the opening of the main water supply regulating valve, thereby achieving disturbance-free switching.

[0080] In the present embodiment, as one of the feasible methods, in the large valve manual control mode, the three-impulse sub-regulation PID generates a large valve opening signal according to the manually input large valve opening setting value and outputs it to the large valve, and the large valve adjusts its opening according to the large valve opening signal output by the three-impulse sub-regulation PID; in the large valve manual control mode, the large valve tracks its own current opening, and the three-impulse sub-regulation PID tracks the opening value of the large valve calculated by the inverse function of the fitting curve based on the current opening of the large valve; when the large valve manual control mode is switched to the automatic control mode, the opening of the large valve is adjusted from the tracking value of the three-impulse sub-regulation PID, which will not cause a sudden change in the opening of the large valve, thereby achieving bypass-free switching.

[0081] In the present embodiment, as one of the feasible methods, in the manual control mode of the small valve, the three-impulse sub-regulation PID generates a small valve opening signal according to the manually input small valve opening setting value and outputs it to the small valve, and the small valve adjusts its opening according to the small valve opening signal output by the three-impulse sub-regulation PID; in the manual control mode of the small valve, the small valve tracks its own current opening, and the three-impulse sub-regulation PID tracks the opening value of the small valve calculated by the inverse function of the fitting curve based on the current opening of the small valve; when the small valve manual control mode is switched to the automatic control mode, the opening of the large valve is adjusted from the tracking value of the three-impulse sub-regulation PID, which will not cause a sudden change in the opening of the small valve, thereby achieving bypass-free switching.

[0082] In this embodiment, as one of the feasible methods, among the large valve and the small valve, when one is in manual control mode and the other is in automatic control mode, the switching from manual control mode to automatic control mode needs to meet the following conditions: the opening of the small valve is less than 87.5% and the opening of the large valve is less than 1%, or the opening of the small valve is greater than 99% and the opening of the large valve is greater than 20%.

[0083] This is to prevent sudden changes in opening when switching from manual control mode to automatic control mode. For example, the large valve is in manual control mode, the small valve is in automatic control mode, and the current openings of the large valve and the small valve are both 50%; when the large valve is switched from manual control mode to automatic control mode, the opening value of the large valve calculated by the inverse function of the fitting curve based on the current opening of the large valve is very small, causing the large valve to suddenly close. The large valve is in automatic control mode, the small valve is in manual control mode, and the current openings of the large valve and the small valve are both 50%; when the small valve is switched from manual control mode to automatic control mode, the opening value of the small valve calculated by the inverse function of the fitting curve based on the current opening of the small valve is very large, causing the small valve to suddenly open.

[0084] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A main feed water flow control system for a sodium-cooled fast reactor, characterized in that: include: A control mode switching module is used to perform disturbance-free switching between the single-impulse control mode and the three-impulse control mode of the main water supply flow in the automatic control mode of the main water supply regulating valve; The three-impulse PID is used to execute the three-impulse control mode of the main water supply flow rate. In the three-impulse control mode of the main water supply flow rate, the three-impulse PID outputs the main water supply regulating valve opening signal to the main water supply regulating valve, and the main water supply regulating valve adjusts the opening according to the main water supply regulating valve opening signal output by the three-impulse PID, thereby controlling the main water supply flow rate. Single impulse PID is used to execute the main water supply flow single impulse control mode; in the main water supply flow single impulse control mode, the single impulse PID outputs the main water supply regulating valve opening signal to the main water supply regulating valve, and the main water supply regulating valve adjusts the opening according to the main water supply regulating valve opening signal output by the single impulse PID, thereby controlling the main water supply flow; The large valve and small valve of the main water supply regulating valve are formed into the main water supply regulating valve through curve fitting.

2. The main feed water flow control system for a sodium-cooled fast reactor according to claim 1, characterized in that: Single impulse PID single impulse control of main water supply flow includes the following steps: Receive the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value; calculate the main feed water flow set value according to the difference between the evaporator outlet sodium temperature and the steam valve outlet sodium temperature set value; According to the main feed water flow setting value, calculate the main feed water regulating valve opening setting value; According to the main water supply regulating valve opening setting value, a main water supply regulating valve opening signal is generated and sent to the main water supply regulating valve; The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal.

3. The main feed water flow control system for a sodium-cooled fast reactor according to claim 1, characterized in that: The three-impulse PID includes: The three-impulse main adjustment PID is used to receive the evaporator outlet sodium temperature, the evaporator outlet sodium temperature set value and the main feed water flow feedforward value; calculate the first set value of the main feed water flow according to the difference between the evaporator outlet sodium temperature and the evaporator outlet sodium temperature set value; add the main feed water flow feedforward value to the first set value of the main feed water flow to obtain the second set value of the main feed water flow; The three-impulse auxiliary PID is used to receive the second set value of the main water supply flow and the measured value of the main water supply flow; calculate the main water supply regulating valve opening set value according to the difference between the second set value of the main water supply flow and the measured value of the main water supply flow; generate the main water supply regulating valve opening signal according to the main water supply regulating valve opening set value and send it to the main water supply regulating valve; The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal.

4. The main feed water flow control system for a sodium-cooled fast reactor according to claim 3, characterized in that: In the single-impulse control mode, the three-impulse auxiliary PID tracks the output value of the single-impulse PID. When the single-impulse control mode is switched to the three-impulse control mode, the output value of the three-impulse auxiliary PID starts from its tracking value. In the three-impulse control mode, the single-impulse PID tracks the output value of the three-impulse sub-regulation PID. When the three-impulse control mode is switched to the single-impulse control mode, the output value of the single-impulse PID starts from its tracking value.

5. The main feed water flow control system for a sodium-cooled fast reactor according to claim 1, characterized in that: The control mode switching module is used to automatically or manually switch the main water supply flow control mode to a three-impulse control mode or a single-impulse control mode under the automatic control mode of the main water supply regulating valve; the manual switching has a higher priority than the automatic switching; In the low power stage of the sodium-cooled fast reactor, the control mode switching module automatically switches to the single-impulse control mode; in the high power stage of the sodium-cooled fast reactor, the control mode switching module automatically switches to the three-impulse control mode.

6. The main feed water flow control system for a sodium-cooled fast reactor according to claim 1, characterized in that: The main feed water flow control system of the sodium-cooled fast reactor also includes: The manual-automatic switching module is used to switch the control mode of the main water supply regulating valve, large valve and small valve to manual control mode or automatic control mode without disturbance.

7. The main feed water flow control system for a sodium-cooled fast reactor according to claim 6, characterized in that: In the manual control mode of the main water supply regulating valve, the three-impulse auxiliary regulation PID generates the main water supply regulating valve opening signal according to the manually input main water supply regulating valve opening setting value and outputs it to the main water supply regulating valve. The main water supply regulating valve adjusts its opening according to the main water supply regulating valve opening signal output by the three-impulse auxiliary regulation PID. In the manual control mode of the main water supply regulating valve, the three-impulse auxiliary regulation PID tracks its own output value. When the manual control of the main water supply regulating valve is switched to the automatic control mode, the opening of the main water supply regulating valve is adjusted from the tracking value of the three-impulse auxiliary regulation PID.

8. The main feed water flow control system for a sodium-cooled fast reactor according to claim 6, characterized in that: In the large valve manual control mode, the three-impulse auxiliary regulation PID generates a large valve opening signal according to the manually input large valve opening setting value and outputs it to the large valve. The large valve adjusts its opening according to the large valve opening signal output by the three-impulse auxiliary regulation PID. In the manual control mode of the large valve, the large valve tracks its current opening, and the three-impulse auxiliary PID tracks the opening value of the large valve calculated by the inverse function of the fitting curve based on the current opening of the large valve; When the large valve manual control mode is switched to the automatic control mode, the opening of the large valve is adjusted from the tracking value of the three-impulse auxiliary regulation PID.

9. The main feed water flow control system for a sodium-cooled fast reactor according to claim 6, characterized in that: In the manual control mode of small valve, the three-impulse auxiliary regulation PID generates a small valve opening signal according to the manually input small valve opening setting value and outputs it to the small valve. The small valve adjusts its opening according to the small valve opening signal output by the three-impulse auxiliary regulation PID. In the manual control mode of the small valve, the small valve tracks its current opening, and the three-impulse auxiliary PID tracks the opening value of the small valve calculated by the inverse function of the fitting curve based on the current opening of the small valve; When the manual control mode of the small valve is switched to the automatic control mode, the opening of the large valve is adjusted from the tracking value of the three-impulse auxiliary regulation PID.

10. The main feed water flow control system for a sodium-cooled fast reactor according to claim 6, characterized in that: When one of the large valve and the small valve is in manual control mode and the other is in automatic control mode, the following conditions must be met to switch from manual control mode to automatic control mode: the small valve opening is less than 87.5% and the large valve opening is less than 1%, or the small valve opening is greater than 99% and the large valve opening is greater than 20%.

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