Control method and system for coping with nuclear power unit SGTR

Abstract

The invention discloses a control method and system for coping with an SGTR of a nuclear power unit, and the method comprises the steps: S1, adjusting the operation state parameters in the nuclear power unit through a control model according to a preset parameter adjustment sequence, and enabling the operation state parameters to comprise the water level of a steam generator and / or the cooling rate of a loop and / or the supercooling degree of the loop; s2, judging whether the currently adjusted running state parameters are within an allowable deviation range of a corresponding preset target value or not; s3, if the running state parameters exceed the allowable deviation range of the preset target value, the control model is adjusted; s4, if the operation state parameter is within the allowable deviation range of the preset target value, the next operation state parameter is selected for adjustment according to the preset parameter adjustment sequence; and S5, repeatedly executing the steps S2 to S4 until all the operation state parameters are within the allowable deviation range of the corresponding preset target value, and realizing stable operation of the nuclear power unit.

Description

Technical Field

[0001] The present invention relates to the field of automatic control technology, and in particular to a control method and system for dealing with SGTR of a nuclear power unit. Background Art

[0002] Steam Generator Tube Rupture (SGTR) is a frequent accident in nuclear power plants. Its treatment measures are complex. The main intervention points include identifying and isolating the broken steam generator, cooling and depressurizing the primary circuit system, terminating the injection and establishing normal charging and discharging, and continuing to cool and depressurize the faulty steam generator. The cooling and depressurization of the primary circuit is the core operation throughout the entire accident handling process. Since its control process belongs to multivariable, strongly coupled time-varying control, automatic control has not yet been achieved. The existing handling method is that the operator manually detects the power plant status according to the requirements of the corresponding accident procedures of the nuclear power plant, analyzes the measures to be taken under the current status, and manually implements control actions to mitigate the consequences of the accident. However, considering that the operator's workload increases, nervousness increases, and psychological pressure rises suddenly during the accident handling process, it is very easy to produce behaviors such as misoperation in this situation, and the superposition of accidents and misoperations will further aggravate the deterioration of the accident.

[0003] The existing patent CN116168866A discloses a method and device for determining the capacity demand of a passive residual heat removal system; the method comprises: sorting out a list of design basis accidents that the passive residual heat removal system has to deal with according to the design characteristics of the nuclear power plant; clarifying the effect achieved by the passive residual heat removal system after each accident according to the list of design basis accidents; determining the limiting operating conditions of the passive residual heat removal system according to the clear effect achieved by the passive residual heat removal system after each accident; analyzing the determined limiting operating conditions, making conservative considerations from aspects such as initial operating conditions, reactor protection and control, and core-related assumptions, and determining the capacity requirements of the passive residual heat removal system under each limiting operating condition; and comprehensively considering the analysis results of the limiting operating conditions to determine a suitable capacity range of the passive residual heat removal system, so as to provide support for the capacity design of the passive residual heat removal system of a new nuclear power plant.

[0004] The existing patent CN107590586A discloses a non-nuclear steam impulse transient test control method for a nuclear power plant, which includes the following steps: S1. Establishing a theoretical calculation model for the non-nuclear steam impulse transient test and performing theoretical calculations; S2. Establishing a single-loop transient test evaluation method based on the theoretical calculation results to determine whether the non-nuclear steam impulse transient test is feasible; S3. Determining the key control parameters of the non-nuclear steam impulse test based on the theoretical calculation results, and formulating a control method for the key control parameters.

[0005] In summary, the above two existing patents do not solve the problem that the key control process is difficult to realize automatic operation after the steam generator heat transfer tube rupture accident occurs. Summary of the invention

[0006] Based on the above technical problems, the present invention proposes a control method and system for dealing with SGTR of nuclear power units, which solves the problem in the prior art that key control processes are difficult to realize automatic operation after a steam generator heat transfer tube rupture accident occurs.

[0007] A control method for coping with SGTR of a nuclear power unit, comprising:

[0008] S1, adjusting the operating state parameters in the nuclear power unit using the control model according to the preset parameter adjustment sequence, the operating state parameters including the steam generator water level and / or the primary circuit cooling rate and / or the primary circuit subcooling degree;

[0009] S2, determining whether the currently adjusted operating state parameter is within the allowable deviation range of the corresponding preset target value;

[0010] S3, if the operating state parameter exceeds the allowable deviation range of the preset target value, the control model is adjusted;

[0011] S4, if the operating state parameter is within the allowable deviation range of the preset target value, selecting the next operating state parameter for adjustment according to the preset parameter adjustment sequence;

[0012] S5, repeating steps S2 to S4 until the operating state parameters are all within the allowable deviation range of the corresponding preset target values, thereby achieving stable operation of the nuclear power unit.

[0013] Furthermore, the preset parameter adjustment order is steam generator water level, primary circuit cooling rate, and primary circuit subcooling degree.

[0014] Further, S5 includes: when the subcooling degree of a circuit is within the allowable deviation range corresponding to the preset target value, determining that the nuclear power unit is in a stable operating state.

[0015] Furthermore, the control model is used to adjust the operating state parameters in the nuclear power unit, including:

[0016] Obtain the operating status parameters and corresponding preset target values ​​at a certain moment;

[0017] Input the operating state parameters and the preset target values ​​into the control model, and output the corresponding control instructions after calculation;

[0018] The operating status parameters of the nuclear power unit are adjusted through control instructions.

[0019] Furthermore, the control instructions include auxiliary water supply control valve instructions, atmospheric exhaust valve comprehensive opening instructions, sprinkler valve opening instructions and electric heater switch instructions.

[0020] Furthermore, the control model is used to adjust the water level of the steam generator in the nuclear power unit, including:

[0021] Obtaining the steam generator water level at a certain moment and the corresponding steam generator water level target value;

[0022] The steam generator water level and the steam generator water level target value are input into the first control model, and after calculation by the first control model, an auxiliary feedwater control valve instruction is output;

[0023] The steam generator water level is regulated by auxiliary feedwater control valve commands.

[0024] Furthermore, the control model is used to adjust the cooling rate of a primary circuit in a nuclear power unit, including:

[0025] Obtain a circuit cooling rate at a certain moment and a corresponding circuit cooling rate target value;

[0026] Inputting the primary circuit cooling rate and the primary circuit cooling rate target value into the second control model, and outputting the initial atmospheric discharge valve opening instruction after calculation by the second control model;

[0027] The cooling rate of a circuit in a nuclear power unit is regulated by means of an initial atmospheric discharge valve opening instruction.

[0028] Furthermore, the target value of the primary circuit cooling rate is determined by the operating number of injection pumps in the nuclear power unit.

[0029] Furthermore, when one injection pump is operated in a nuclear power unit, the target value of the cooling rate of a circuit corresponds to the first preset target value; when two injection pumps are operated in a nuclear power unit, the target value of the cooling rate of a circuit corresponds to the second preset target value.

[0030] Furthermore, the control model is used to adjust the cooling rate of a primary circuit in the nuclear power unit, and further includes:

[0031] inputting the auxiliary water supply control valve command into a preset feedforward function;

[0032] Based on the calculation result of the feedforward function and the initial atmospheric exhaust valve opening instruction, the atmospheric exhaust valve comprehensive opening instruction is generated and output to adjust the primary circuit cooling rate.

[0033] Furthermore, the feedforward function corresponds to formula 1,

[0034] Formula 1, f1 = kx1 + b, where x1 is the auxiliary water supply control valve opening obtained in real time, ΔT1 is the first cooling rate increase value under normal and stable operating conditions, ΔT2 is the second cooling rate increase value under normal and stable operating conditions, ΔV1 is the first step opening of the auxiliary water supply control valve opening, ΔV2 is the second step opening of the auxiliary water supply control valve opening, and j is the gain of the atmospheric discharge valve to the cooling rate.

[0035] Furthermore, the control model is used to adjust the subcooling degree of the primary circuit in the nuclear power unit, including:

[0036] Obtain the primary circuit subcooling degree and the corresponding primary circuit subcooling degree target value at a certain moment;

[0037] Inputting the primary circuit subcooling degree and the primary circuit subcooling degree target value into the third control model, and outputting the spray valve opening degree instruction after calculation by the third control model;

[0038] The subcooling degree of one circuit is adjusted by the spray valve opening instruction.

[0039] Furthermore, the target value of primary circuit subcooling is determined by Formula 2:

[0040]

[0041] Among them, a is the primary circuit subcooling at the current moment, b is the stabilizer water level at the current moment, and x2 is the stabilizer water level during the regulation process.

[0042] Furthermore, it also includes:

[0043] The electric heater determination function is used to determine the electric heater switch command. The electric heater determination function is expressed by formula three. Formula three:

[0044]

[0045] Among them, p is the evaluation index at time t;

[0046] The subcooling degree of one circuit is adjusted by the switch command of the electric heater.

[0047] Furthermore, the evaluation index is determined by Formula 4. Formula 4:

[0048]

[0049] Where f3(ti) is the target value of primary circuit subcooling at the tith second, ΔT sat (ti) is the subcooling degree of the first circuit at the tith second.

[0050] Furthermore, S3 includes:

[0051] If the operating state parameters exceed the allowable deviation range of the preset target value, the parameters of the control model are adjusted through the adaptive rules in the control model.

[0052] Based on the above technical solution, a control method for dealing with SGTR of a nuclear power unit of the present invention has at least the following beneficial effects:

[0053] 1. A control method for coping with SGTR of a nuclear power unit of the present invention, by presetting the parameter adjustment sequence, uses a control model to adjust the operating state parameters in the nuclear power unit one by one until the operating state parameters are all within the allowable deviation range of the corresponding preset target value, so as to achieve stable operation of the nuclear power unit. This method introduces automatic control into the accident handling process, which can effectively avoid cognitive errors of operators. Early intervention operations can reduce the severity of accident consequences, alleviate economic losses and effectively avoid the release of radioactivity to the environment.

[0054] 2. A control method for coping with the SGTR of a nuclear power unit of the present invention establishes a correlation between the primary circuit subcooling, the pressurizer water level, and the primary circuit subcooling target value when using a control model to adjust the operating status parameters in the nuclear power unit one by one, so that the primary circuit subcooling changes with the pressurizer water level, thereby achieving effective control of the primary circuit subcooling and achieving a stable operating state of the nuclear power unit.

[0055] To achieve the same purpose as the above method, the present invention also proposes a control system for dealing with the SGTR of a nuclear power plant.

[0056] A control system for coping with SGTR of a nuclear power unit, the system comprising N controllers, the system being used for:

[0057] N controllers are used to calculate the operating status parameters of the nuclear power unit, and corresponding control instructions are generated and output according to the calculation results to adjust the operating status of the nuclear power unit. The control instructions include auxiliary feed water control valve instructions, atmospheric discharge valve comprehensive opening instructions, spray valve opening instructions and electric heater switch instructions.

[0058] Furthermore, N controllers are used to calculate the operating state parameters of the nuclear power unit, and corresponding control instructions are generated and output according to the calculation results, including:

[0059] The steam generator water level at a certain moment and the corresponding steam generator water level target value are input into the first controller, and after calculation by the first controller, an auxiliary feedwater control valve instruction is output to adjust the steam generator water level;

[0060] The first circuit cooling rate at a certain moment and the corresponding first circuit cooling rate target value are input to the second controller, and the second controller outputs the initial atmospheric discharge valve opening instruction after calculation;

[0061] The auxiliary water supply control valve command is input into a preset feedforward function, and based on the calculation result of the feedforward function and the initial atmospheric discharge valve opening command, the atmospheric discharge valve comprehensive opening command is output to adjust the primary circuit cooling rate;

[0062] The subcooling degree of a circuit at a certain moment and the corresponding subcooling degree target value of the circuit are input into the third controller, and after calculation by the third controller, a spray valve opening instruction is output to adjust the water level of the pressurizer and the subcooling degree of the circuit.

[0063] Based on the above technical solution, a control system for dealing with SGTR of a nuclear power unit of the present invention has at least the following beneficial effects:

[0064] 1. The control system for coping with SGTR of nuclear power units of the present invention disassembles the multivariable, strongly coupled time-varying control process, and designs controllers to adjust the operating state parameters respectively, and finally determines the parameters of stable operation through integrated debugging. The verification results show that its control effect in the time dimension and the comparison of the deviation range from the target value are better than manual control, and the automatic control process of the control system has the possibility of replacing manual operation.

[0065] 2. The control system for coping with SGTR of nuclear power units of the present invention can effectively mitigate the severity of accident consequences, reduce economic losses and effectively reduce the probability of radioactive release to the environment by timely and automatically adjusting operating status parameters to enable the nuclear power units to reach a stable operating state. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0067] Figure 1 A flow chart of a control method for dealing with SGTR of a nuclear power unit according to an embodiment of the present invention;

[0068] Figure 2 A schematic diagram of the control system principle of an embodiment of the present invention;

[0069] Figure 3 It is a schematic diagram of the verification test effect of a specific embodiment of the present invention. DETAILED DESCRIPTION

[0070] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments 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.

[0071] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0072] Example

[0073] In order to solve the problem in the prior art that it is difficult to realize automatic operation of key control processes after a steam generator heat transfer tube rupture accident occurs, the present invention proposes a control method and system for dealing with the SGTR of a nuclear power unit.

[0074] To achieve the above objective, the present invention proposes a control method for coping with SGTR of a nuclear power unit.

[0075] like Figure 1 A flow chart of a control method for dealing with SGTR of a nuclear power plant unit according to an embodiment of the present invention is shown in FIG. 1 , and the method comprises the following steps:

[0076] S1, according to the preset parameter adjustment sequence, use the control model to adjust the operating state parameters in the nuclear power unit.

[0077] In this embodiment, the preset parameter adjustment order is steam generator water level, primary circuit cooling rate, and primary circuit subcooling. When the steam generator water level is within the allowable deviation range corresponding to the preset target value, the primary circuit cooling rate is adjusted, and finally the primary circuit subcooling is adjusted.

[0078] Furthermore, the control model is used to adjust the operating state parameters in the nuclear power unit, including the following sub-steps:

[0079] S101, obtain the operating state parameters and corresponding preset target values ​​at a certain moment; S102, input the operating state parameters and preset target values ​​into the control model, and output the corresponding control instructions after calculation; further, the control instructions include auxiliary water supply control valve instructions, atmospheric discharge valve comprehensive opening instructions, spray valve opening instructions and electric heater switch instructions. S103, adjust the operating state parameters of the nuclear power unit through control instructions. The following will introduce the process of adjusting each parameter separately.

[0080] (1) Use the control model to adjust the water level of the steam generator in the nuclear power unit.

[0081] The specific adjustment process is as follows: obtain the steam generator water level at a certain moment and the corresponding steam generator water level target value K; input the steam generator water level and the steam generator water level target value into the first control model, and output the auxiliary feed water control valve command after calculation by the first control model; finally adjust the steam generator water level through the auxiliary feed water control valve command, and the limit range of the valve command is 0-100. Furthermore, according to the nuclear power unit regulations, the steam generator water level target value is generally -0.58 meters.

[0082] (2) The control model is used to adjust the cooling rate of a circuit in a nuclear power unit.

[0083] The specific adjustment process is as follows: obtain the primary-loop cooling rate and the corresponding primary-loop cooling rate target value at a certain moment; input the primary-loop cooling rate and the primary-loop cooling rate target value into the second control model, and output the initial atmospheric discharge valve opening instruction after calculation by the second control model; adjust the primary-loop cooling rate in the nuclear power unit through the initial atmospheric discharge valve opening instruction.

[0084] Furthermore, the target value of the primary cooling rate is determined by the number of operating injection pumps in the nuclear power unit. When one injection pump is in operation in the nuclear power unit, the target value of the primary cooling rate corresponds to the first preset target value, C1; when two injection pumps are in operation in the nuclear power unit, the target value of the primary cooling rate corresponds to the second preset target value, C2. The specific target values ​​of the primary cooling rate C1 and C2 can be determined according to actual conditions.

[0085] In addition, in order to offset the influence of the first control model on the control effect of the second control model when adjusting the water level of the steam generator, the present invention proposes to add a feedforward function, and determine the comprehensive opening instruction of the atmospheric discharge valve based on the output of the feedforward function and the output of the second control model to reduce the regulating pressure of the steam discharge valve. Specifically, the following steps are included:

[0086] First, the auxiliary water supply control valve command is input into a preset feedforward function.

[0087] Furthermore, the feedforward function corresponds to formula 1, f1=kx1+b, where x1 is the auxiliary water supply control valve opening obtained in real time, ΔT1 is the first cooling rate increase value under normal and stable operating conditions, ΔT2 is the second cooling rate increase value under normal and stable operating conditions, ΔV1 is the first step opening of the auxiliary water supply control valve opening, ΔV2 is the second step opening of the auxiliary water supply control valve opening, and j is the gain of the atmospheric discharge valve to the cooling rate. The feedforward function can be understood as, under a relatively stable operating condition during the operation of the nuclear power unit (when the main parameters such as the pressure, temperature, and power of the primary circuit change within a range of less than 1%, it can be considered a relatively stable operating condition), the auxiliary water supply control valve opening is increased by a small step opening ΔV1, and the corresponding cooling rate increase ΔT1 is recorded at this time; when the nuclear power unit operating condition is restored to the operating condition before the disturbance is added, a larger step opening ΔV2 is added, and the cooling rate increase ΔT2 at this time is recorded. It should be understood that the step opening can take different values ​​according to actual conditions. In this embodiment, ΔV1 takes a value of 2% and ΔV2 takes a value of 10%.

[0088] Secondly, based on the calculation result of the feedforward function and the initial atmospheric exhaust valve opening instruction, the atmospheric exhaust valve comprehensive opening instruction is generated and output to adjust the primary circuit cooling rate.

[0089] (3) Use the control model to adjust the subcooling of the primary circuit in the nuclear power unit.

[0090] The specific adjustment process is as follows: obtain the subcooling degree of a circuit at a certain moment and the corresponding target value of the subcooling degree of a circuit; input the subcooling degree of a circuit and the target value of the subcooling degree of a circuit into the third control model, and output the spray valve opening instruction after calculation by the third control model; adjust the subcooling degree of a circuit through the spray valve opening instruction.

[0091] Furthermore, the target value of primary circuit subcooling is determined by Formula 2:

[0092]

[0093] Among them, a is the subcooling of the primary circuit at the current moment, which is calculated by subtracting the current steam temperature from the saturation temperature corresponding to the steam pressure of the primary circuit, b is the stabilizer water level at the current moment, and x2 is the stabilizer water level during the adjustment process.

[0094] Furthermore, in another embodiment of the present invention, an electric heater determination function is used to determine an electric heater switch command, and then the primary circuit subcooling degree is adjusted by the electric heater switch command.

[0095] Specifically, the electric heater determination function is expressed by Formula 3. Formula 3:

[0096]

[0097] Among them, p is the evaluation index at time t.

[0098] Furthermore, the evaluation index is determined by Formula 4. Formula 4:

[0099]

[0100] Where f3(ti) is the target value of primary circuit subcooling at the tith second, ΔT sat (ti) is the subcooling degree of the first circuit at the tith second.

[0101] S2, determining whether the currently adjusted operating state parameter is within the allowable deviation range of the corresponding preset target value.

[0102] Taking the cooling rate of a circuit as an example, after adjusting the cooling rate of a circuit, it is determined whether the cooling rate of the circuit is within the allowable deviation range of the corresponding preset target value. In a specific embodiment of the present invention, the target value of the cooling rate of the circuit is -56°C / h, the allowable deviation range of the target value of the cooling rate of the circuit is ±6%, and the degree of supercooling is greater than or equal to 20°C.

[0103] S3: If the operating state parameter exceeds the allowable deviation range of the preset target value, the control model is adjusted.

[0104] Furthermore, if the operating state parameter exceeds the allowable deviation range of the preset target value, the parameter of the control model is adjusted by the adaptive rule in the control model.

[0105] S4: If the operating status parameter is within the allowable deviation range of the preset target value, the next operating status parameter is selected for adjustment according to the preset parameter adjustment sequence.

[0106] Taking the steam generator water level as an example, if the currently adjusted operating status parameter is within the allowable deviation range of the corresponding preset target value, the cooling rate of the first circuit is adjusted according to the preset parameter adjustment sequence.

[0107] S5, repeating steps S2 to S4 until all the operating state parameters are within the allowable deviation range of the corresponding preset target values.

[0108] Furthermore, when the subcooling degree of a circuit is within the allowable deviation range of the corresponding preset target value, it is determined that the nuclear power unit is in a stable operating state.

[0109] In summary, it can be seen from the above description that an embodiment of a control method for coping with SGTR of a nuclear power unit of the present invention achieves the following technical effects:

[0110] 1. A control method for coping with SGTR of a nuclear power unit of the present invention, by presetting the parameter adjustment sequence, uses a control model to adjust the operating state parameters in the nuclear power unit one by one until the operating state parameters are all within the allowable deviation range of the corresponding preset target value, so as to achieve stable operation of the nuclear power unit. This method introduces automatic control into the accident handling process, which can effectively avoid cognitive errors of operators. Early intervention operations can reduce the severity of accident consequences, alleviate economic losses and effectively avoid the release of radioactivity to the environment.

[0111] 2. A control method for coping with the SGTR of a nuclear power unit of the present invention establishes a correlation between the primary circuit subcooling, the pressurizer water level, and the primary circuit subcooling target value when using a control model to adjust the operating status parameters in the nuclear power unit one by one, so that the primary circuit subcooling changes with the pressurizer water level, thereby achieving effective control of the primary circuit subcooling and achieving a stable operating state of the nuclear power unit.

[0112] To achieve the above object, the present invention also proposes a control system for coping with the SGTR of a nuclear power unit.

[0113] A control system for dealing with SGTR of a nuclear power unit, the system includes N controllers, which are used to calculate the operating state parameters of the nuclear power unit, and then generate and output corresponding control instructions according to the calculation results to adjust the operating state of the nuclear power unit. Figure 2 FIG. 1 shows a schematic diagram of a control system principle of an embodiment of the present invention, as shown in FIG. Figure 2 As shown, the control system includes three controllers, and the first, second and third controllers are used to calculate the operating state parameters of the nuclear power unit to generate corresponding control instructions. The control instructions include auxiliary feedwater control valve instructions, atmospheric discharge valve comprehensive opening instructions, spray valve opening instructions and electric heater switch instructions.

[0114] The process of cooling and depressurizing a primary circuit after a heat transfer tube rupture accident of a steam generator of a nuclear power unit involves many variables and a high degree of coupling. The present invention decouples the process of cooling and depressurizing a primary circuit into cooling of the primary circuit after the accident and control of the water level and pressure of a pressurizer.

[0115] Specifically, the cooling process of the first circuit after the accident is used to realize the automatic execution of the cooling process of the first circuit after the accident, so that the actual cooling rate is controlled within the deviation range of the cooling rate setting value. The cooling process can be understood as that after the accident occurs and the protection system is triggered, it is necessary to use the steam bypass system to cool the first circuit of the reactor at a set rate for a period of time. After the temperature and pressure of the first circuit drop to a certain level, it is switched to the residual heat removal system for continued cooling. The control method is mainly to affect the flow of cooling water injected into the first circuit by adjusting the valve opening. This embodiment realizes the cooling of the first circuit after the accident by adjusting and observing the changes in the water level of the steam generator.

[0116] The pressurizer water level and pressure control is used to maintain the pressurizer water level within the expected range and control the pressure according to the target value under accident conditions, with a static deviation of less than 1%. Under normal conditions, the pressurizer water level and pressure can be adjusted automatically. Under accident conditions, the system model changes, and the specific model varies depending on the type and severity of the accident. Manual control is required. At the same time, the pressure control of the first circuit, the pressurizer liquid level control, and the cooling process control are all related during the control process. Specifically, the pressure and liquid level of the first circuit are adjusted by adjusting the opening of the pressurizer spray valve. The cooling rate of the first circuit is controlled by adjusting the opening of the atmospheric discharge valve.

[0117] Specifically, the operating status parameters of the nuclear power unit are calculated, and corresponding control instructions are generated and output according to the calculation results, including the following processes:

[0118] The steam generator water level at a certain moment and the corresponding steam generator water level target value are input to the first controller, and after calculation by the first controller, the auxiliary water supply control valve instruction is output to adjust the steam generator water level. When the steam generator water level is stable within the deviation range of the steam generator water level target value, the first circuit cooling rate target value is determined, and the first circuit cooling rate at a certain moment and the corresponding first circuit cooling rate target value are input to the second controller, and after calculation by the second controller, the initial atmospheric discharge valve valve opening instruction is output. After adjustment by the initial atmospheric discharge valve valve opening instruction, when the first circuit cooling rate is stable within the first circuit cooling rate target value deviation range, the auxiliary water supply control valve instruction is input to the preset feedforward function, and based on the calculation result of the feedforward function and the initial atmospheric discharge valve valve opening instruction, the atmospheric discharge valve valve comprehensive opening instruction is output to further adjust the first circuit cooling rate. After the cooling rate of the primary circuit is stabilized, the primary circuit subcooling at a certain moment and the corresponding primary circuit subcooling target value are input into the third controller, and the third controller outputs the spray valve opening instruction after calculation to adjust the pressurizer water level and the primary circuit subcooling. Furthermore, the system also adjusts the opening time and number of electric heaters through the electric heater function to better adjust the primary circuit subcooling. When the primary circuit subcooling is within the primary circuit subcooling target value deviation range, the regulation is terminated to achieve stable operation of the nuclear power unit.

[0119] like Figure 3 As shown, in the process of adjusting the cooling rate of a circuit, curve A represents the process of adjusting the cooling rate of a circuit by a certain manual control, curve B represents the process of adjusting the cooling rate of a circuit by another manual control, and curve C represents the process of adjusting the cooling rate of a circuit by a control system for dealing with the SGTR of a nuclear power unit in a specific embodiment of the present invention, and the target value of the cooling rate of a circuit is -56°C / h. Figure 3 It can be seen that the average relative error of manual control A is 11.1807℃ / h, and the actual cooling rate deviation is 19.97% of the cooling rate setting value. The average relative error of manual control B is 39.3597℃ / h, and the actual cooling rate deviation is 70.29% of the cooling rate setting value. The control system can make the cooling rate quickly approach the setting value, and the deviation from the setting value is not large after 700s. The average relative error of the control system adjustment is 3.2997℃ / h, and the actual cooling rate is 5.89% of the cooling rate setting value. The adjustment effect is significantly better than manual operation. From the perspective of accident mitigation, the application of this control system can effectively reduce the severity of accident consequences, reduce economic losses and effectively reduce the probability of radioactive release to the environment. If it is extended to other operating modes of nuclear power plants, automatic control can improve operating efficiency and reduce the risk of misoperation, which will increase the economy of operation while also improving safety.

[0120] It should be understood that a control system for dealing with SGTR of a nuclear power unit is consistent with the description of a corresponding control method embodiment for dealing with SGTR of a nuclear power unit, so it will not be described in detail in this embodiment.

[0121] In summary, it can be seen from the above description that an embodiment of the control system for coping with the SGTR of a nuclear power plant unit of the present invention achieves the following technical effects:

[0122] 1. The control system for coping with SGTR of nuclear power units of the present invention disassembles the multivariable, strongly coupled time-varying control process, and designs controllers to adjust the operating state parameters respectively, and finally determines the parameters of stable operation through integrated debugging. The verification results show that its control effect in the time dimension and the comparison of the deviation range from the target value are better than manual control, and the automatic control process of the control system has the possibility of replacing manual operation.

[0123] 2. The control system for coping with SGTR of nuclear power units of the present invention can effectively mitigate the severity of accident consequences, reduce economic losses and effectively reduce the probability of radioactive release to the environment by timely and automatically adjusting operating status parameters to enable the nuclear power units to reach a stable operating state.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0125] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0126] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, which can be embodied in any computer-readable medium for use by an instruction execution system, apparatus or device (such as a computer-based system, a system including a processor or other system that can fetch instructions from an instruction execution system, apparatus or device and execute instructions), or used in combination with these instruction execution systems, apparatuses or devices.

[0127] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0128] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

Claims

1. A control method for coping with SGTR of a nuclear power unit, characterized in that: include: S1, adjusting the operating state parameters in the nuclear power unit using the control model according to the preset parameter adjustment sequence, wherein the operating state parameters include the steam generator water level and / or the primary circuit cooling rate and / or the primary circuit subcooling degree; S2, determining whether the currently adjusted operating state parameter is within the allowable deviation range of the corresponding preset target value; S3, if the operating state parameter exceeds the allowable deviation range of the preset target value, adjusting the control model; S4, if the operating state parameter is within the allowable deviation range of the preset target value, selecting the next operating state parameter for adjustment according to the preset parameter adjustment sequence; S5, repeating steps S2 to S4 until the operating state parameters are all within the allowable deviation range of the corresponding preset target values, thereby achieving stable operation of the nuclear power unit.

2. The method according to claim 1, characterized in that The preset parameter adjustment order is steam generator water level, primary circuit cooling rate, and primary circuit subcooling degree.

3. The method according to claim 2, characterized in that The S5 includes: when the primary circuit subcooling degree is within the allowable deviation range of the corresponding preset target value, determining that the nuclear power unit is in a stable operating state.

4. The method according to any one of claims 1 to 3, characterized in that: The control model is used to adjust the operating state parameters of the nuclear power unit, including: Obtaining the operating state parameters and corresponding preset target values ​​at a certain moment; Input the operating state parameter and the preset target value into the control model, and output corresponding control instructions after calculation; The operating state parameters of the nuclear power unit are adjusted through the control instructions.

5. The method according to claim 4, characterized in that The control instructions include auxiliary water supply control valve instructions, atmospheric discharge valve comprehensive opening instructions, spray valve opening instructions and electric heater switch instructions.

6. The method according to claim 5, characterized in that The control model is used to regulate the water level of the steam generator in the nuclear power unit, including: Obtaining the steam generator water level at a certain moment and the corresponding steam generator water level target value; Inputting the steam generator water level and the steam generator water level target value into a first control model, and outputting the auxiliary feedwater control valve instruction after calculation by the first control model; The steam generator water level is adjusted by the auxiliary feedwater control valve command.

7. The method according to claim 5, characterized in that The control model is used to adjust the cooling rate of the primary circuit in the nuclear power unit, including: Obtain a circuit cooling rate at a certain moment and a corresponding circuit cooling rate target value; Inputting the primary circuit cooling rate and the primary circuit cooling rate target value into a second control model, and outputting an initial atmospheric discharge valve opening instruction after calculation by the second control model; The cooling rate of a circuit in a nuclear power unit is adjusted by means of the initial atmospheric discharge valve opening instruction.

8. The method according to claim 7, characterized in that The target value of the primary circuit cooling rate is determined by the number of operating injection pumps in the nuclear power unit.

9. The method according to claim 8, characterized in that When one injection pump is running in the nuclear power unit, the target value of the first loop cooling rate corresponds to the first preset target value; when two injection pumps are running in the nuclear power unit, the target value of the first loop cooling rate corresponds to the second preset target value.

10. The method according to claim 7, characterized in that The control model is used to adjust the cooling rate of a primary circuit in a nuclear power unit, and also includes: Inputting the auxiliary water supply control valve instruction into a preset feedforward function; Based on the calculation result of the feedforward function and the initial atmospheric exhaust valve opening instruction, the atmospheric exhaust valve comprehensive opening instruction is generated and output to adjust the primary circuit cooling rate.

11. The method according to claim 10, characterized in that The feedforward function corresponds to formula 1, In the formula 1, f1=kx1+b, where x1 is the auxiliary water supply control valve opening obtained in real time, ΔT1 is the first cooling rate increase value under normal and stable operating conditions, ΔT2 is the second cooling rate increase value under normal and stable operating conditions, ΔV1 is the first step opening of the auxiliary water supply control valve opening, ΔV2 is the second step opening of the auxiliary water supply control valve opening, and j is the gain of the atmospheric discharge valve to the cooling rate.

12. The method according to claim 5, characterized in that The control model is used to adjust the subcooling of the primary circuit in the nuclear power unit, including: Obtain the primary circuit subcooling degree and the corresponding primary circuit subcooling degree target value at a certain moment; Inputting the primary circuit subcooling degree and the primary circuit subcooling degree target value into a third control model, and outputting the spray valve opening instruction after calculation by the third control model; The subcooling degree of the primary circuit is adjusted by the valve opening instruction of the spray valve.

13. The method according to claim 12, characterized in that The primary circuit subcooling target value is determined by Formula 2, where: Among them, a is the primary circuit subcooling at the current moment, b is the stabilizer water level at the current moment, and x2 is the stabilizer water level during the regulation process.

14. The method according to claim 12, characterized in that Also includes: The electric heater switch command is determined by using an electric heater determination function, and the electric heater determination function is expressed by Formula 3. Formula 3: Among them, p is the evaluation index at time t; The subcooling degree of the primary circuit is adjusted by the electric heater switching command.

15. The method according to claim 14, characterized in that The evaluation index is determined by formula 4, wherein: Where f3(ti) is the target value of primary circuit subcooling at the tith second, ΔT sat (ti) is the subcooling degree of the primary circuit at the ti-th second.

16. The method according to claim 1, characterized in that The S3 includes: If the operating state parameter exceeds the allowable deviation range of the preset target value, the parameters of the control model are adjusted according to the adaptive rules in the control model.

17. A control system for coping with SGTR of a nuclear power plant, characterized in that: The system comprises N controllers, and the system is used for: The N controllers are used to calculate the operating status parameters of the nuclear power unit, and corresponding control instructions are generated and output according to the calculation results to adjust the operating status of the nuclear power unit. The control instructions include auxiliary water supply control valve instructions, atmospheric discharge valve comprehensive opening instructions, spray valve opening instructions and electric heater switch instructions.

18. The system according to claim 17, characterized in that Utilizing the N controllers to calculate the operating state parameters of the nuclear power unit, generating and outputting corresponding control instructions according to the calculation results, including: The steam generator water level at a certain moment and the corresponding steam generator water level target value are input into the first controller, and the first controller outputs the auxiliary feedwater control valve instruction after calculation to adjust the steam generator water level; The primary circuit cooling rate at a certain moment and the corresponding primary circuit cooling rate target value are input to the second controller, and the second controller outputs the initial atmospheric discharge valve opening instruction after calculation; Inputting the auxiliary water supply control valve instruction into a preset feedforward function, and outputting the comprehensive opening instruction of the atmospheric discharge valve based on the calculation result of the feedforward function and the initial atmospheric discharge valve opening instruction, so as to adjust the cooling rate of the primary circuit; The subcooling degree of a circuit at a certain moment and the corresponding subcooling degree target value of the circuit are input into the third controller, and the third controller outputs the valve opening instruction of the spray valve after calculation to adjust the water level of the stabilizer and the subcooling degree of the circuit.

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