Nuclear power plant rapid power reduction transient analysis method and device

Abstract

The invention provides a transient analysis method and device for rapid power reduction of a nuclear power plant, and the method comprises the steps: carrying out the transient calculation of a transient process inputted by a rapid power reduction system on the basis of stable parameters under a steady-state working condition; according to the change condition of the first preset parameter, triggering conditions of a shutdown protection signal, an atmosphere release valve opening signal and a steam generator safety valve opening signal are obtained; if the shutdown protection signal, the atmosphere release valve opening signal or the steam generator safety valve opening signal is triggered, the power reduction amplitude of rapid power reduction is increased until it is ensured that any one of the shutdown protection signal, the atmosphere release valve opening signal and the steam generator safety valve opening signal is not triggered any more in the load shedding transient process. According to the method, the rapid power reduction system is put into the transient process, and the triggering condition of the protection system in the transient process is effectively evaluated, so that the technical problem of how to reduce the size of the condenser by reducing redundant steam in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the field of reactor transient analysis, and in particular to a method and device for rapid power reduction transient analysis of a nuclear power plant. Background Art

[0002] The condenser of a nuclear power plant is the cold source of the thermal cycle system of the nuclear power plant. Its basic function is to receive the exhaust steam from the turbine and condense it into water, forming a closed thermal cycle. At the same time, its blades receive the steam directly discharged from the steam exhaust system and condense it into water.

[0003] In order to improve the economic efficiency of nuclear power plants, reducing the size of the condenser is an important way. However, in order to reduce the size of the condenser, it is necessary to reduce the excess steam as much as possible, thereby reducing the demand for condensing steam in the condenser. In other words, how to reduce the size of the condenser by reducing the excess steam has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present invention provides a method and device for analyzing the rapid power reduction transient of a nuclear power plant, which solves the technical problem of how to reduce the size of a condenser by reducing excess steam in the prior art by putting a rapid power reduction system into operation during the transient process and effectively evaluating the changes in main parameters and the triggering of a protection system during the transient process.

[0005] The present invention provides a method for analyzing the rapid power reduction transient of a nuclear power plant, comprising: on the basis of parameter stability under steady-state conditions, performing transient calculation on the transient process of a rapid power reduction system being put into operation, so as to obtain the change of a first preset parameter in the transient process of the rapid power reduction system being put into operation, wherein the rapid power reduction is performed by releasing a preset rapid power reduction rod group by the rapid power reduction system during the transient process of the rapid power reduction system being put into operation, and the first preset parameter comprises nuclear power and steam pressure; according to the change of the first preset parameter, obtaining the triggering conditions of a shutdown protection signal, an atmospheric release valve opening signal and a steam generator safety valve opening signal; if the shutdown protection signal, the atmospheric release valve opening signal or the steam generator safety valve opening signal is triggered, increasing the power reduction amplitude of the rapid power reduction until ensuring that any of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is no longer triggered in the load shedding transient process.

[0006] In a specific embodiment of the present invention, the first preset parameter also includes an online deviation from nucleate boiling ratio. The nuclear power plant rapid power reduction transient analysis method also includes: obtaining the triggering condition of the online deviation from nucleate boiling ratio protection signal according to the change of the online deviation from nucleate boiling ratio; if the online deviation from nucleate boiling ratio protection signal is triggered, increasing the power reduction amplitude of the rapid power reduction until the minimum online deviation from nucleate boiling ratio in the transient process of the rapid power reduction system being put into operation is higher than the online deviation from nucleate boiling ratio setting value.

[0007] In a specific embodiment of the present invention, on the basis of the stability of parameters under steady-state conditions, before performing transient calculations for the transient process of the rapid power reduction system, the nuclear power plant rapid power reduction transient analysis method also includes: using a system analysis program that simulates the behavior of the coolant system to establish a system program analysis model related to transient analysis; using the system program analysis model related to transient analysis, steady-state debugging of key system parameters until the deviation between the key system parameters and the target value is within 1%, so as to obtain the initial state and basic assumption parameters that meet the initial operating conditions. The key system parameters include nuclear power, initial pressure of the pressurizer, and average reactor temperature.

[0008] In a specific embodiment of the present invention, the system program analysis model related to transient analysis includes a primary loop system model, a secondary loop system main equipment model closely related to transient analysis, and a rapid power reduction system model.

[0009] A system analysis program that simulates the behavior of the coolant system is used to establish a system program analysis model related to transient analysis, including: using a system analysis program that simulates the behavior of the coolant system, hydraulic geometric modeling of the primary circuit system and the main equipment of the secondary circuit system that is closely related to the transient analysis is performed to obtain the primary circuit system model and the main equipment model of the secondary circuit system that is closely related to the transient analysis; modeling the rapid power reduction system to obtain the rapid power reduction system model.

[0010] In a specific embodiment of the present invention, the system program analysis model related to transient analysis also includes a plurality of thermal component models and a control system model.

[0011] A system analysis program simulating the behavior of the coolant system is used to establish a system program analysis model related to transient analysis, which also includes: establishing multiple thermal component models to simulate the heat exchange of the fluid. At least one thermal component model includes core fuel and steam generator heat transfer tube thermal components; modeling the control system to obtain a control system model, the control system includes a power regulation system, a feed water regulation system, a pressurizer pressure control system and a turbine bypass control system; simulating the reactor protection signal according to the reactor protection design parameters.

[0012] In a specific embodiment of the present invention, on the basis of parameter stability under steady-state conditions, transient calculation is performed for the transient process of the rapid power reduction system being put into operation to obtain the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation, including: on the basis of parameter stability under steady-state conditions, a curve of the change of the second preset parameter over time provided by the transient analysis of the secondary circuit system is used as the boundary condition of the transient analysis, the second preset parameter includes the steam flow rate of the steam inlet turbine, the first-stage pressure of the steam turbine, the pressure of the feed water tank and the temperature of the feed water tank; according to the boundary conditions of the transient analysis, the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation is obtained through transient calculation, the first The preset parameters also include reactor coolant temperature, primary circuit pressure, steam generator secondary side pressure, feedwater flow rate and feedwater pump speed; if the feedwater flow rate in the first preset parameter is consistent with the feedwater flow rate provided by the transient analysis of the secondary circuit system, the transient analysis is terminated; if there is a difference between the feedwater flow rate in the first preset parameter and the feedwater flow rate provided by the transient analysis of the secondary circuit system, the change of the first preset parameter is fed back to the transient analysis of the secondary circuit system as the boundary condition of the transient analysis of the secondary circuit system, the secondary circuit transient analysis is re-performed and steam parameters and feedwater parameters are provided for iteration until the feedwater flow rate in the first preset parameter is consistent with the feedwater flow rate provided by the transient analysis of the secondary circuit system and the iteration converges.

[0013] In a specific embodiment of the present invention, on the basis of parameter stability under steady-state conditions, transient calculation is performed on the transient process of the rapid power reduction system being put into operation to obtain changes in the first preset parameter during the transient process of the rapid power reduction system being put into operation, including: on the basis of parameter stability under steady-state conditions, according to the action of the transient process of the rapid power reduction system being put into operation, the transient process of the rapid power reduction system being put into operation is simulated using a system program analysis model related to transient analysis to calculate changes in the first preset parameter during the transient process of the rapid power reduction system being put into operation.

[0014] In a specific embodiment of the present invention, the transient process of rapid power reduction system input includes full-power load shedding to plant power and full-power steam turbine shutdown.

[0015] A second aspect of the present invention provides a nuclear power plant rapid power reduction transient analysis device, which includes a transient calculation module, an acquisition module and an adjustment module.

[0016] The transient calculation module is used to perform transient calculation on the transient process of the rapid power reduction system on the basis of stable parameters under steady-state conditions, so as to obtain the change of the first preset parameter in the transient process of the rapid power reduction system. The transient process of the rapid power reduction system is to release the preset rapid power reduction rod group by using the rapid power reduction system to perform rapid power reduction. The first preset parameter includes nuclear power and steam pressure.

[0017] The acquisition module is used to acquire the triggering conditions of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal according to the change of the first preset parameter.

[0018] The adjustment module is used to increase the power reduction amplitude of the rapid power reduction if the shutdown protection signal, the atmospheric release valve opening signal or the steam generator safety valve opening signal is triggered, until it is ensured that any of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is no longer triggered during the load rejection transient process.

[0019] The beneficial effect of the technical solution of the present invention lies in that, by performing transient calculation on the transient process of the rapid power reduction system being put into operation, when any one of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is triggered during the transient process of the rapid power reduction system being put into operation, the power reduction amplitude of the rapid power reduction is increased, thereby ensuring that the transient process of the rapid power reduction system being put into operation no longer triggers any of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal, thereby ensuring that the system can reach a new stable operating condition before the transient process, the protection signal will not be triggered during the transient process, and the atmospheric release valve and the steam generator safety valve will not be opened, so that the transient process of the rapid power reduction system being put into operation meets the corresponding design criteria requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a flow chart of a method for rapid power reduction transient analysis of a nuclear power plant provided in one embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to further understand the present invention, the embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the present invention.

[0022] After careful study, it was found that as the condenser steam bypass capacity requirements decrease, it is necessary to increase the nuclear power reduction rate in transients such as load shedding to prevent overpressure in the secondary circuit. In some embodiments, a rapid power reduction system is set up. When a large load shedding occurs (such as the magnitude of the load shedding is not less than the capacity of the turbine bypass system), the purpose of rapidly reducing the nuclear power is achieved by releasing a preset rapid power reduction rod group to reduce the emission requirements borne by the condenser steam bypass. At the same time, the number of bypass valves and protection logic are optimized to improve the maintainability of the reactor, reduce the probability of emergency shutdown of the reactor due to valve malfunction, and improve the operating performance of the unit. After the rapid power reduction system is set up, in the transient analysis of large and rapid load changes such as load shedding, it is necessary to consider the role of the rapid power reduction system and make a more realistic assessment of the transient process.

[0023] Based on this, an embodiment of the present invention discloses a method for analyzing a nuclear power plant's rapid power reduction transient state. The execution subject of the method for analyzing a nuclear power plant's rapid power reduction transient state may be a processor or a server. Figure 1 The nuclear power plant rapid power reduction transient analysis method may include the following steps.

[0024] S1: On the basis of the stability of parameters under steady-state conditions, a transient calculation is performed for the transient process of the rapid power reduction system being put into operation to obtain the change of the first preset parameter during the transient process of the rapid power reduction system being put into operation. The transient process of the rapid power reduction system being put into operation is to rapidly reduce power by using the rapid power reduction system to release a preset rapid power reduction rod group. The first preset parameter includes nuclear power and steam pressure.

[0025] The transient process of rapid power reduction system input can be any transient process that uses rapid power reduction system for rapid power reduction, including but not limited to the beginning and end of life, full power load shedding to plant power, full power load shedding to the power level that just does not trigger rapid power reduction, intermediate power load shedding to plant power, etc. The first preset parameter can also include but not limited to reactor coolant temperature, primary circuit pressure, steam generator secondary side pressure, feed water flow rate and feed water pump speed, etc.

[0026] S2: According to the change of the first preset parameter, the triggering conditions of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal are obtained.

[0027] For example, the processor can automatically calculate the negative change rate of the neutron fluence rate from the nuclear power. If the absolute value of the negative change rate of the neutron fluence rate is greater than the preset value of the negative change rate of the neutron fluence rate (for example, 5% FP / 2s), the processor can give a feedback result of triggering a shutdown protection signal. If the steam pressure is greater than the preset steam pressure value (for example, 7.5Mpa), the processor can give a feedback result of triggering an atmospheric release valve opening signal or a steam generator safety valve opening signal.

[0028] S3: If the shutdown protection signal, the atmospheric release valve opening signal or the steam generator safety valve opening signal is triggered, the power reduction amplitude of the rapid power reduction is increased until it is ensured that none of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is triggered during the load rejection transient process.

[0029] It should be noted that the design criteria require that: the protection signal will not be triggered during the transient process, and the atmospheric relief valve and steam generator safety valve will not open. If the shutdown protection signal, atmospheric relief valve opening signal or steam generator safety valve opening signal is not triggered, no adjustment will be made.

[0030] According to the technical solution provided in the embodiment of the present invention, by performing transient calculation on the transient process of the rapid power reduction system being put into operation, when any one of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is triggered during the transient process of the rapid power reduction system being put into operation, the power reduction amplitude of the rapid power reduction is increased, thereby ensuring that the transient process of the rapid power reduction system being put into operation no longer triggers any one of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal, thereby ensuring that the system can reach a new stable operating condition before the transient process, the protection signal will not be triggered during the transient process, and the atmospheric release valve and the steam generator safety valve will not be opened, so that the transient process of the rapid power reduction system being put into operation meets the corresponding design criteria requirements.

[0031] The transient process of the rapid power reduction system being put into operation can be determined based on the operating conditions of the nuclear power plant and the design of the rapid power reduction system, and the typical transient of the rapid power reduction system being put into operation can be determined.

[0032] For example, in at least one embodiment of the present invention, the transient process of the rapid power reduction system includes full-power load shedding to plant power and full-power steam turbine shutdown. In this way, since the two transient processes of full-power load shedding to plant power and full-power steam turbine shutdown have the highest requirements on the rapid power reduction system, the two transient processes of full-power load shedding to plant power and full-power steam turbine shutdown are selected as typical transient processes of the rapid power reduction system. If the two transient processes of full-power load shedding to plant power and full-power steam turbine shutdown are guaranteed not to trigger the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal, then correspondingly, other transient processes of the rapid power reduction system are also guaranteed not to trigger the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal.

[0033] In at least one embodiment of the present invention, the first preset parameter also includes an online deviation from nucleate boiling ratio. The nuclear power plant rapid power reduction transient analysis method also includes the following steps.

[0034] S4: According to the change of the online deviation from the nucleate boiling ratio, the triggering condition of the online deviation from the nucleate boiling ratio protection signal is obtained.

[0035] For example, a program capable of simulating the calculation of the online departure from nucleate boiling ratio (DNBR) may be used to calculate and output the online departure from nucleate boiling ratio, so that the processor can obtain the online departure from nucleate boiling ratio. The processor may compare the minimum value of the online departure from nucleate boiling ratio with the online departure from nucleate boiling ratio setting value to obtain the triggering condition of the online departure from nucleate boiling ratio protection signal.

[0036] S5: If the online deviation from nucleate boiling ratio protection signal is triggered, the power reduction amplitude of the rapid power reduction is increased until the minimum online deviation from nucleate boiling ratio in the transient process of the rapid power reduction system being put into operation is higher than the online deviation from nucleate boiling ratio setting value.

[0037] In the embodiment of the present invention, since the rapid power reduction rod group will have a great impact on the core power distribution after being released, if the online deviation from the nucleate boiling ratio protection is adopted, the above steps S4 and S5 ensure that the minimum online deviation from the nucleate boiling ratio in the transient process of the rapid power reduction system being put into operation is higher than the online deviation from the nucleate boiling ratio setting value (that is, a limiting criterion requirement), and accordingly, ensure that the online deviation from the nucleate boiling ratio protection will not be triggered in the transient process of the rapid power reduction system being put into operation.

[0038] In at least one embodiment of the present invention, before the above S1, the nuclear power plant rapid power reduction transient analysis method further includes S01 and S02.

[0039] S01: Use a system analysis program that simulates the behavior of the coolant system to establish a system program analysis model related to transient analysis.

[0040] For example, system analysis programs that simulate the behavior of the coolant system use either a one-dimensional core or a three-dimensional core code.

[0041] S02: Using the system program analysis model related to transient analysis, the key parameters of the system are debugged in a steady state until the deviation between the key parameters of the system and the target value is within 1%, so as to obtain the initial state and basic assumption parameters that meet the initial operating conditions. The key parameters of the system include nuclear power, initial pressure of the pressurizer and average temperature of the reactor.

[0042] Specifically, based on the basic assumptions such as the initial operating conditions, neutronic parameters and the preset rapid power reduction rod group, by utilizing the system program analysis model related to transient analysis, the key parameters of the system are steadily debugged to obtain the initial state that meets the requirements of the initial operating conditions, and the corresponding basic assumption parameters are set.

[0043] It should be noted that the initial operating condition may be the initial operating condition of the reactor, that is, the full power state, and the average temperature, pressure and power of the reactor coolant may all adopt the optimal estimated flow rate.

[0044] For neutronic parameters, the corresponding physical database can be used or the corresponding neutronic parameters can be input according to the cycle and burnup at the time of calculation, the feedback coefficient, the delayed neutron fraction and other parameters. For example, if the analysis is performed at the beginning of the C1 cycle life, the physical database at the beginning of the C1 cycle life, or the fuel and moderator feedback coefficient, the delayed neutron fraction, the prompt neutron lifetime, the adjustment rod value and the like at the beginning of the C1 cycle life should be used.

[0045] For the preset rapid power reduction rod group, the corresponding value and cross section can be adopted according to the rapid power reduction rod group combination determined by the reactor core design. For example, if the rapid power reduction rod group combination determined by the reactor core design is the SA rod group, the value or cross section of the SA rod group is input in the calculation. Since the parameters required for the rapid power reduction system calculation have been established in the system program analysis model related to transient analysis, when the load reduction (= load rejection) amplitude exceeds a certain value (for example, the load reduction amplitude exceeds the capacity of the turbine bypass system) and the power level is high (for example, higher than the set value, the set value range is 30% to 80%), the rapid power reduction system is triggered and the preset rapid power reduction rod group is released.

[0046] In at least one embodiment of the present invention, the system program analysis model related to transient analysis includes a primary loop system model, a secondary loop system main equipment model closely related to transient analysis, and a rapid power reduction system model. S01-1 and S01-2 are a specific implementation of the above S01.

[0047] S01-1: Use a system analysis program that simulates the behavior of the coolant system to perform hydraulic geometric modeling on the primary circuit system and the main equipment of the secondary circuit system that is closely related to the transient analysis, so as to obtain the primary circuit system model and the main equipment model of the secondary circuit system that is closely related to the transient analysis.

[0048] It should be noted that the modeling process ensures that the block division is reasonable and the connection relationship between the parts is correct. The primary circuit system includes the core, descending section, lower chamber, lower head, upper chamber, upper head, stabilizer, cold pipe section, hot pipe section, main pump, primary side of steam generator, etc.

[0049] The main equipment of the secondary circuit system closely related to transient analysis includes feedwater pump, feedwater regulating valve, steam generator secondary side and turbine bypass system, etc. The parameters of the secondary circuit system closely related to transient analysis, such as steam parameters of the steam inlet turbine, feedwater pressure and enthalpy value, can adopt boundary conditions, that is, the curves of these parameters changing with time are input into the model to calculate the changes of parameters such as steam temperature, steam pressure, feedwater flow rate, etc. in transient state.

[0050] The main equipment of the secondary circuit system closely related to transient analysis can also include steam turbines, condensers and circulating water pumps. According to the characteristics of each equipment, the changes in secondary circuit parameters such as feed water enthalpy, steam flow rate and other parameters in transient state are calculated.

[0051] S01-2: Model the rapid power reduction system to obtain a rapid power reduction system model.

[0052] It should be noted that when modeling the rapid power reduction system, the rapid power reduction system can be simulated according to the rapid power reduction system design logic and parameters, and the rapid power reduction system design logic such as parameter filtering link and fixed value comparison link. The initial rod position and value of the rapid power reduction rod group can also be input according to the core design.

[0053] In the embodiment of the present invention, by adding a rapid power reduction system model to the system program analysis model related to transient analysis, the rapid power reduction system model can be used to effectively simulate the transient process of the rapid power reduction system being put into operation.

[0054] In at least one embodiment of the present invention, the system program analysis model related to transient analysis also includes a plurality of thermal component models and a control system model. The above S01 may also include S01-3 to S01-5.

[0055] S01-3: Establish multiple thermal component models to simulate the heat exchange of the fluid. At least one thermal component model includes core fuel and steam generator heat transfer tube thermal components.

[0056] During the modeling process, ensure that parameters such as heat transfer area and material properties are correct.

[0057] S01-4: Model the control system to obtain the control system model. The control system includes the power regulation system, feed water regulation system, regulator pressure control system and turbine bypass control system.

[0058] It should be noted that when modeling the control system, it can be established according to the control system design logic and parameters. The control parameters are consistent with the power plant design.

[0059] S01-5: Simulate the reactor protection signal according to the reactor protection design parameters.

[0060] It should be noted that the reactor protection signal includes but is not limited to a shutdown protection setting, a delay time, and a shutdown protection action.

[0061] In at least one embodiment of the present invention, S1-1 to S1-4 are a specific implementation of the above S1.

[0062] S1-1: On the basis of the stability of parameters under steady-state conditions, the second preset parameter change curve over time provided by the transient analysis of the secondary circuit system is used as the boundary condition of the transient analysis. The second preset parameters include the steam flow rate of the steam turbine, the first stage pressure of the steam turbine, the pressure of the feedwater tank, and the temperature of the feedwater tank.

[0063] It should be noted that the first-stage pressure of the steam turbine is used to characterize the steam turbine load.

[0064] S1-2: According to the boundary conditions of the transient analysis, the change of the first preset parameter in the transient process of the rapid power reduction system is obtained through transient calculation. The first preset parameter also includes the reactor coolant temperature, the primary circuit pressure, the steam generator secondary side pressure, the feed water flow rate and the feed water pump speed.

[0065] Specifically, the boundary conditions of the transient analysis are input into the program, and the program can calculate the first preset parameters together.

[0066] S1-3: If the water supply flow rate in the first preset parameter is consistent with the water supply flow rate provided by the transient analysis of the secondary circuit system, the transient analysis is terminated.

[0067] S1-4: If there is a difference between the water supply flow in the first preset parameter and the water supply flow provided by the transient analysis of the secondary circuit system, the change of the first preset parameter will be fed back to the transient analysis of the secondary circuit system as the boundary condition of the transient analysis of the secondary circuit system, and the secondary circuit transient analysis will be re-performed and the steam parameters and water supply parameters will be provided for iteration until the water supply flow in the first preset parameter is consistent with the water supply flow provided by the transient analysis of the secondary circuit system and the iteration converges.

[0068] Steam parameters include but are not limited to the steam flow rate of the steam turbine and the first stage pressure of the steam turbine. Feedwater parameters include but are not limited to the pressure of the feedwater tank and the temperature of the feedwater tank.

[0069] In at least one embodiment of the present invention, S1-5 is a specific implementation of the above S1.

[0070] S1-5: On the basis of parameter stability under steady-state conditions, according to the action of the transient process of the rapid power reduction system being put into operation, the transient process of the rapid power reduction system being put into operation is simulated using a system program analysis model related to transient analysis to calculate the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation.

[0071] It should be noted that in transient analysis, it is also possible to further evaluate whether the rapid power reduction rod group falls into the core and introduces negative reactivity after being triggered, and whether the nuclear power reduction reaches the expected range, further ensuring that the rapid power reduction system is correctly simulated.

[0072] In the embodiment of the present invention, the first preset parameter in the transient process of the rapid power reduction system is quickly obtained by simulating the transient process of the rapid power reduction system by using a system program analysis model related to transient analysis.

[0073] The nuclear power plant rapid power reduction transient analysis method of the above-mentioned embodiment can be applied to the normal transient analysis of a nuclear power plant that adopts a rapid power reduction design. By determining typical transients, establishing an analysis model, performing transient calculations, and obtaining the main parameters in the transient process, the changes in the main parameters in the transient process and the triggering of the protection system are evaluated.

[0074] At least one embodiment of the present invention further provides a device for analyzing rapid power reduction transients in a nuclear power plant. The device for analyzing rapid power reduction transients in a nuclear power plant includes a transient calculation module, an acquisition module, and an adjustment module.

[0075] The transient calculation module is used to perform transient calculation on the transient process of the rapid power reduction system on the basis of stable parameters under steady-state conditions, so as to obtain the change of the first preset parameter in the transient process of the rapid power reduction system. The transient process of the rapid power reduction system is to release the preset rapid power reduction rod group by using the rapid power reduction system to perform rapid power reduction. The first preset parameter includes nuclear power and steam pressure.

[0076] The acquisition module is used to acquire the triggering conditions of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal according to the change of the first preset parameter.

[0077] The adjustment module is used to increase the power reduction amplitude of the rapid power reduction if the shutdown protection signal, the atmospheric release valve opening signal or the steam generator safety valve opening signal is triggered, until it is ensured that any of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is no longer triggered during the load rejection transient process.

[0078] It should be noted that the nuclear power plant rapid power reduction transient analysis device is a device corresponding to the nuclear power plant rapid power reduction transient analysis method in the above-mentioned embodiment, includes the corresponding technical features of the nuclear power plant rapid power reduction transient analysis method in the above-mentioned embodiment, and can achieve the corresponding technical effects, which will not be repeated here.

[0079] At least one embodiment of the present invention further provides a computer device, which includes a processor and a memory. The processor is used to execute a method for analyzing a nuclear power plant rapid power reduction transient state provided by any of the above embodiments of the present invention. The memory is used to store executable instructions of the processor, such as an application program. The number of processors may be one or more. The application program stored in the memory may include one or more modules, each corresponding to a set of instructions. In addition, the processor is configured to execute instructions to execute the above method for analyzing a nuclear power plant rapid power reduction transient state.

[0080] The computer device may also include a power supply component configured to manage power of the computer device, a wired or wireless network interface configured to connect the computer device to a network, and an input / output (I / O) interface. The computer device may operate based on an operating system stored in the memory, such as Windows Server 2003. TM , Mac OSX TM , Unix TM , Linux TM , FreeBSD TM or similar.

[0081] At least one embodiment of the present invention further provides a computer-readable storage medium on which executable instructions of a computer are stored. When the executable instructions are executed by a processor, a method for analyzing the rapid power reduction transient of a nuclear power plant provided in any of the above embodiments of the present invention is implemented.

[0082] A non-transitory computer-readable storage medium, when the instructions in the storage medium are executed by the processor of the computer device, enables the computer device to execute the nuclear power plant rapid power reduction transient analysis method. The nuclear power plant rapid power reduction transient analysis method is executed by an agent program.

[0083] Those skilled in the art will appreciate that the algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0084] At least one embodiment of the present invention further provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements a nuclear power plant rapid power reduction transient analysis method provided by any of the above embodiments of the present invention.

[0085] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a computer program product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the nuclear power plant rapid power reduction transient analysis method of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program check codes.

[0086] It should be noted that the combination of the various technical features in the embodiments of the present invention is not limited to the combination recorded in the embodiments of the present invention or the combination recorded in the specific embodiments, and all technical features recorded in the present invention can be freely combined or combined in any way unless there is a contradiction between them.

[0087] As shown in the present invention and claims, unless the context clearly indicates an exception, the words "a", "an" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the term "comprising" only indicates that the steps and elements that have been clearly identified are included, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0088] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0089] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0090] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing rapid power reduction transient of a nuclear power plant, characterized in that: include: On the basis of the stability of parameters under steady-state conditions, a transient calculation is performed for the transient process of the rapid power reduction system being put into operation to obtain the change of the first preset parameter during the transient process of the rapid power reduction system being put into operation. During the transient process of the rapid power reduction system being put into operation, the rapid power reduction is performed by releasing a preset rapid power reduction rod group by utilizing the rapid power reduction system. The first preset parameter includes nuclear power and steam pressure. According to the change of the first preset parameter, the triggering conditions of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal are obtained; If the shutdown protection signal, the atmospheric release valve opening signal or the steam generator safety valve opening signal is triggered, the power reduction amplitude of the rapid power reduction is increased until it is ensured that none of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is triggered during the load rejection transient process.

2. The method for rapid power reduction transient analysis of a nuclear power plant according to claim 1, characterized in that: The first preset parameter also includes an online deviation from nucleate boiling ratio, and the nuclear power plant rapid power reduction transient analysis method also includes: According to the change of the online deviation from the nucleate boiling ratio, the triggering condition of the online deviation from the nucleate boiling ratio protection signal is obtained; If the online deviation from nucleate boiling ratio protection signal is triggered, the power reduction amplitude of the rapid power reduction is increased until the minimum online deviation from nucleate boiling ratio during the transient process of the rapid power reduction system being put into operation is higher than the online deviation from nucleate boiling ratio setting value.

3. The method for rapid power reduction transient analysis of a nuclear power plant according to claim 1, characterized in that: On the basis of stable parameters under steady-state conditions, before performing transient calculations for the transient process of rapid power reduction system input, the nuclear power plant rapid power reduction transient analysis method also includes: Using a system analysis program that simulates the behavior of the coolant system, a system program analysis model related to transient analysis is established; Using the system program analysis model related to transient analysis, the key system parameters are debugged in a steady state until the deviation between the key system parameters and the target value is within 1%, so as to obtain the initial state and basic assumption parameters that meet the initial operating conditions. The key system parameters include nuclear power, initial pressurizer pressure and average reactor temperature.

4. The method for rapid power reduction transient analysis of a nuclear power plant according to claim 3, characterized in that: The system program analysis models related to transient analysis include the primary circuit system model, the secondary circuit system main equipment model closely related to transient analysis, and the rapid power reduction system model. The system analysis program for simulating the behavior of the coolant system is used to establish a system program analysis model related to transient analysis, including: Using a system analysis program that simulates the behavior of the coolant system, hydraulic geometric modeling is performed on the primary circuit system and the main equipment of the secondary circuit system that is closely related to the transient analysis, so as to obtain the primary circuit system model and the main equipment model of the secondary circuit system that is closely related to the transient analysis; A rapid power reduction system is modeled to obtain a rapid power reduction system model.

5. The method for rapid power reduction transient analysis of a nuclear power plant according to claim 4, characterized in that: The system program analysis model related to transient analysis also includes multiple thermal component models and control system models. Wherein, the system analysis program simulating the behavior of the coolant system is used to establish a system program analysis model related to transient analysis, and further includes: Establish multiple thermal component models to simulate the heat exchange of fluids, at least one thermal component model includes core fuel and steam generator heat transfer tube thermal components; model the control system to obtain the control system model, the control system includes a power regulation system, a feed water regulation system, a pressurizer pressure control system and a turbine bypass control system; simulate the reactor protection signal according to the reactor protection design parameters.

6. The method for rapid power reduction transient analysis of a nuclear power plant according to claim 1, characterized in that: On the basis of the stability of the parameters under steady-state conditions, a transient calculation is performed for the transient process of the rapid power reduction system being put into operation to obtain the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation, including: On the basis of the stability of parameters under steady-state conditions, the time-varying curve of the second preset parameters provided by the transient analysis of the secondary circuit system is used as the boundary condition of the transient analysis. The second preset parameters include the steam flow rate of the steam turbine, the first-stage pressure of the steam turbine, the pressure of the feedwater tank, and the temperature of the feedwater tank. According to the boundary conditions of the transient analysis, the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation is obtained through transient calculation, and the first preset parameter also includes the reactor coolant temperature, the primary circuit pressure, the secondary side pressure of the steam generator, the feed water flow rate and the feed water pump speed; If the water supply flow rate in the first preset parameter is consistent with the water supply flow rate provided by the transient analysis of the secondary circuit system, the transient analysis is terminated; If there is a difference between the water feed flow in the first preset parameter and the water feed flow provided by the transient analysis of the secondary circuit system, the change of the first preset parameter will be fed back to the transient analysis of the secondary circuit system as the boundary condition of the transient analysis of the secondary circuit system. The secondary circuit transient analysis will be re-performed and steam parameters and water feed parameters will be provided for iteration until the water feed flow in the first preset parameter is consistent with the water feed flow provided by the transient analysis of the secondary circuit system and the iteration converges.

7. The method for rapid power reduction transient analysis of a nuclear power plant according to claim 1, characterized in that: On the basis of the stability of the parameters under steady-state conditions, a transient calculation is performed for the transient process of the rapid power reduction system being put into operation to obtain the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation, including: On the basis of parameter stability under steady-state conditions, according to the action of the transient process of the rapid power reduction system being put into operation, the transient process of the rapid power reduction system being put into operation is simulated using a system program analysis model related to transient analysis, so as to calculate the change of the first preset parameter in the transient process of the rapid power reduction system being put into operation.

8. The method for analyzing the rapid power reduction transient of a nuclear power plant according to any one of claims 1 to 7, characterized in that: The transient process of rapid power reduction system operation includes full-power load shedding to plant power and full-power steam turbine shutdown.

9. A nuclear power plant rapid power reduction transient analysis device, characterized in that: Including transient calculation module, acquisition module and adjustment module, The transient calculation module is used to perform transient calculation on the transient process of the rapid power reduction system under steady-state conditions, on the basis of stable parameters, so as to obtain the change of the first preset parameter in the transient process of the rapid power reduction system. The transient process of the rapid power reduction system is to release a preset rapid power reduction rod group by using the rapid power reduction system to perform rapid power reduction. The first preset parameter includes nuclear power and steam pressure. The acquisition module is used to acquire the triggering conditions of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal according to the change of the first preset parameter; The adjustment module is used to increase the power reduction amplitude of the rapid power reduction if the shutdown protection signal, the atmospheric release valve opening signal or the steam generator safety valve opening signal is triggered, until it is ensured that any of the shutdown protection signal, the atmospheric release valve opening signal and the steam generator safety valve opening signal is no longer triggered during the load rejection transient process.

10. A computer device, characterized in that: include: A processor, configured to execute a method for analyzing a nuclear power plant rapid power reduction transient state according to any one of claims 1 to 8; as well as A memory is used to store executable instructions of the processor.

11. A computer-readable storage medium having computer executable instructions stored thereon, characterized in that: When the executable instructions are executed by the processor, a nuclear power plant rapid power reduction transient analysis method according to any one of claims 1 to 8 is implemented.

12. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, a method for analyzing rapid power reduction transient of a nuclear power plant according to any one of claims 1 to 8 is implemented.

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