Transient analysis method and system for multi-component working medium system of gas cooled reactor

Abstract

The invention discloses a transient analysis method and system for a multi-component working medium system of a gas cooled reactor, and relates to the technical field of safety numerical analysis of a nuclear reactor system.The transient analysis method comprises the steps that forming reasons of multi-component working media in the gas cooled reactor are analyzed, and data are collected and preprocessed; a first loop and a second loop of the system are constructed, and mathematical models for thermal hydraulic analysis are constructed respectively; and performing multi-component working medium transient analysis, and outputting the temperature of each control body. According to the method, the uniform mass conservation equation of the mixture is established for the multiple components of working media in the system, the conservation equation does not need to be independently listed for each component, the solving process is simplified, and the calculation efficiency is improved. Meanwhile, the method can be used for analyzing migration of each component working medium in the loop due to coolant flowing. Besides, in the transient analysis method of the system, the influence of the composition, concentration and thermal parameters of the multi-component working medium on the thermal hydraulic solution of the whole system in the generation and migration process is considered, so that the method accords with reality, and the accuracy of the method is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear reactor system safety numerical analysis, and in particular to a transient analysis method and system for a gas-cooled reactor multi-component working fluid system. Background Art

[0002] A gas-cooled reactor is a type of nuclear reactor that uses gas as a coolant to transfer heat within the reactor. The natural uranium gas-cooled reactor uses metallic natural uranium fuel, graphite as a moderator, and carbon dioxide as a coolant. The first gas-cooled power reactor was the Calder Hall reactor in the UK. Although natural uranium is cheap and easy to obtain, the coolant outlet temperature is limited. The improved gas-cooled reactor uses uranium dioxide fuel and stainless steel cladding, and slightly enriched uranium is used instead of natural uranium. After the improvement, the core outlet temperature is increased and the nuclear power efficiency is improved. In order to further improve the performance of gas-cooled reactors and improve coolants and core materials, high-temperature gas-cooled reactors were studied in the 1950s. High-temperature gas-cooled reactors use ceramic-coated particle fuel and the coolant is inert gas helium, which increases the coolant outlet temperature and the thermal efficiency for power generation.

[0003] There may be more than one working fluid in a gas-cooled reactor. For example, if a breach occurs in the primary circuit pressure boundary and air enters the primary circuit of the system, if the oxygen in the air reacts chemically with the material in the reaction pair, multi-component gas will be further produced. Therefore, it is necessary to study the analysis method of multi-component working fluid system.

[0004] In the existing transient analysis methods of gas-cooled reactor systems, a lot of research has been done on thermal hydraulics, but there are fewer studies on the treatment of multi-component working fluids in the system and their impact on thermal hydraulics. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: how to consider the influence of multi-component working fluids on the thermal solution of the entire system, and at the same time simplify the solution ideas of multi-component working fluids, improve the solution process, and increase the solution speed.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a transient analysis method for a multi-component working fluid system of a gas-cooled reactor, comprising the following steps:

[0008] Analyze the formation causes of multi-component working fluids in gas-cooled reactors and collect data for preprocessing;

[0009] Construct mathematical models for thermal hydraulic analysis for the primary and secondary circuits of the system;

[0010] Based on the constructed mathematical model of thermal hydraulic analysis, transient analysis of multi-component working fluids is carried out and the temperature of each control body is output.

[0011] As a preferred embodiment of the transient analysis method of a multi-component working fluid system of a gas-cooled reactor according to the present invention, the formation cause of the multi-component working fluid in the gas-cooled reactor includes that the formation cause of the gas mixture in the primary loop of the gas-cooled reactor system is graphite corrosion caused by an intake accident, and the working fluids present include helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, water vapor, water and hydrogen;

[0012] The working fluid produced in the secondary circuit of the gas-cooled reactor system is water.

[0013] As a preferred embodiment of the transient analysis method of a multi-component working fluid system of a gas-cooled reactor according to the present invention, the data includes that the formation of the gas mixture in the primary loop of the gas-cooled reactor system is caused by graphite corrosion caused by an intake accident, and the working fluids present include helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, water vapor, water and hydrogen;

[0014] The preprocessing is to calculate the specific components of each working fluid, the reaction rate of each chemical reaction and the change rate of each working fluid concentration according to the graphite corrosion phenomenon caused by the intake accident, and correct the data to delete abnormal values ​​to achieve consistency.

[0015] As a preferred solution of the transient analysis method of a gas-cooled reactor multi-component working fluid system of the present invention, the mathematical models for respectively constructing thermal hydraulic analysis include mass conservation equations, energy conservation equations, momentum conservation equations or pressure equations;

[0016] The coolant mixture in the primary loop must satisfy the mass conservation of various types of working fluids that occur in the primary loop of the gas-cooled reactor system where graphite corrosion occurs. The system pressure field is solved and the mass conservation equation of the mixture is established. The expression is:

[0017]

[0018] Among them, ε g is the gas fraction in the grid cell, ρ m is the coolant mixture density, t is the time, M o is the molecular weight of the coolant mixture, is the fluid flow rate, S m is the mass source term, is the cross-derivative term due to the difference in molecular weight of different gases in the coolant mixture;

[0019] To solve the mixed working fluid in a circuit, it is necessary to establish the momentum conservation equation and the energy conservation equation, and the expression is:

[0020]

[0021]

[0022] Where W is resistance, P is pressure, T g is the fluid temperature, λ g is the effective thermal conductivity of the fluid, α is the heat transfer coefficient between the solid and the fluid, α(T g -T s ) is the convective heat transfer term between the solid and the coolant gas,

[0023] is the pressure gradient, is the acceleration due to gravity, is the fluid temperature gradient, c g is the specific heat capacity of the fluid.

[0024] As a preferred solution of the transient analysis method of a gas-cooled reactor multi-component working fluid system of the present invention, the cross-derivative term generated by the difference in molecular weight of different gases includes two solution methods;

[0025] The first solution is to use the differential product rule to solve it. The mass conservation equation is established for the uniform working fluid. The expression is:

[0026]

[0027] Combined with the mass conservation equation of the mixture, the cross derivative term generated by the difference in molecular weight of different gases in the coolant mixture is obtained, and the expression is:

[0028]

[0029] The second solution is to solve the molar mass and density of the mixed working fluid by the molar fraction of each working fluid, and then output the total number of moles after combining them, which is expressed as:

[0030]

[0031]

[0032]

[0033]

[0034] Where i is the i-th working fluid in the mixture, n i is the number of moles of working fluid i, are the molecular weight of working fluid i and the molar mass of the mixed working fluid, respectively. is the mass of working fluid i, ρ m is the density of the mixed working fluid, ∑n i is the total number of moles, ε gis the gas fraction in the grid cell;

[0035] Mixing speed between different working fluids For convection, the mass conservation equation for each working fluid is expressed as:

[0036]

[0037] Among them, S il is the mass exchange between the working fluids, S i is the mass source term of the working fluid, is a constant;

[0038] Through algebraic transformation, it can be expressed as:

[0039]

[0040] The mass conservation equation of the mixed working fluid is expressed as:

[0041]

[0042]

[0043] Among them, n i is the number of moles of working fluid i, is the fluid flow rate, S i is the mass source term of the working fluid, V is the volume, ρ m is the coolant mixture density.

[0044] As a preferred solution of the transient analysis method of a multi-component working fluid system of a gas-cooled reactor described in the present invention, a basic mathematical model of thermal hydraulic analysis is established for the working fluid water in the secondary circuit;

[0045] The mass conservation equation is expressed as:

[0046]

[0047] The energy conservation equation is expressed as:

[0048]

[0049] Among them, m i is the mass of the working fluid in the control volume i, W i is the outlet mass flow rate of control body i, W i-1 is the outlet mass flow rate of control body i-1, τ is the time quantity, H i is the specific enthalpy of the working fluid in the control volume i, V i is the volume of control volume i, Q i In order to control the heat received by the working fluid in body i from the wall, P s For pressure;

[0050] Using the fixed boundary method, the secondary side working fluid calculation adopts the constant volume condition, and the expression is:

[0051]

[0052] Among them, i is the specific volume of control volume i;

[0053] The derivative of specific volume with respect to time is split into the derivative of enthalpy with respect to time and the derivative of pressure with respect to time, and the equation written under constant volume condition is converted into an equation containing enthalpy and pressure, which can be expressed as:

[0054]

[0055] The pressure equation is obtained:

[0056] Outputting the temperature of each control body includes outputting the temperature of each control body and correlating the parameters between the multi-component working fluids, the working fluids exchange heat through the wall between the first and second circuits, the water on the secondary side takes away the heat of the mixed working fluid on the primary side, and the energy conservation equation of the mixed working fluid on the primary side is combined with the energy conservation equation of the wall surface to solve the heat exchange parameters on both sides;

[0057] The control bodies are divided into staggered grids, and the basic conservation equations are discretized using the finite volume integration method. At the current temperature of each control body, under the assumption of the mass flow rate of each control body, the mass conservation equation and momentum conservation equation of the working fluid are combined to obtain the pressure of each control body. The pressure of each control body is substituted into the mass conservation equation to obtain the updated value of the mass flow rate of each control body. The mass flow rate of each control body is substituted into the energy conservation equation to obtain the temperature of each control body. The control body temperature is converged and the temperature convergence is added.

[0058] If the temperature of the control body has completed convergence, the current thermal characteristic parameters pressure, density, and temperature are brought into the chemical reaction calculation to obtain the concentration of each working fluid under the current working condition, and then the new temperature value is obtained through calculation and feedback. The new temperature value is set as the current temperature, and the pressure of each control body, the updated value of the mass flow of each control body, and the temperature of each control body are repeatedly calculated until the concentration of each component working fluid and the temperature of the thermal characteristic parameters converge;

[0059] If the temperature of the control body has not converged, the mass conservation equation and momentum conservation equation of the working fluid are repeatedly combined to output the pressure of each control body, the updated value of the mass flow rate of each control body, and the temperature of each control body until the temperature converges;

[0060] The temperature converges, and the expression is:

[0061] max|T k+1 -T k |≤1.0 -3

[0062] Among them, T k is the temperature value calculated for the kth time, T k+1 is the temperature value calculated for the k+1th time

[0063] Among them, m i is the mass of the working fluid in the control volume i, υ i is the specific volume of control body i, H i is the specific enthalpy of the working fluid in the control volume i, P s For pressure.

[0064] As a preferred solution of the transient analysis method of a gas-cooled reactor multi-component working fluid system described in the present invention, wherein the outputting of the temperature of each control body includes outputting the temperature of each control body and correlating the parameters between the multi-component working fluids, the working fluid exchanges heat through the wall between the first and second circuits, the water on the secondary side takes away the heat of the mixed working fluid on the primary side, the energy conservation equation of the mixed working fluid on the primary side and the energy conservation equation of the wall are combined to solve the heat exchange parameters on both sides;

[0065] The control bodies are divided into staggered grids, and the basic conservation equations are discretized using the finite volume integration method. At the current temperature of each control body, under the assumption of the mass flow rate of each control body, the mass conservation equation and momentum conservation equation of the working fluid are combined to obtain the pressure of each control body. The pressure of each control body is substituted into the mass conservation equation to obtain the updated value of the mass flow rate of each control body. The mass flow rate of each control body is substituted into the energy conservation equation to obtain the temperature of each control body. The temperature of the control body is converged and the temperature convergence is added.

[0066] If the temperature of the control body has completed convergence, the current thermal characteristic parameters pressure, density, and temperature are brought into the chemical reaction calculation to obtain the concentration of each working fluid under the current working condition, and then the new temperature value is obtained through calculation and feedback. The new temperature value is set as the current temperature, and the pressure of each control body, the updated value of the mass flow of each control body, and the temperature of each control body are repeatedly calculated until the concentration of each component working fluid and the temperature of the thermal characteristic parameters converge;

[0067] If the temperature of the control body has not converged, the mass conservation equation and momentum conservation equation of the working fluid are repeatedly combined to output the pressure of each control body, the updated value of the mass flow rate of each control body, and the temperature of each control body until the temperature converges;

[0068] The temperature converges, and the expression is:

[0069] max|T k+1 -T k |≤1.0 -3

[0070] Among them, T k is the temperature value calculated for the kth time, Tk+1 is the temperature value obtained by the k+1th calculation.

[0071] Another object of the present invention is to provide a transient analysis system for a gas-cooled reactor multi-component working fluid system, which can coordinate the work of various modules to solve the problems of low analysis accuracy and slow response speed in the transient analysis of multi-component working fluids in the existing gas-cooled reactor system, and the problem that it cannot reflect the actual operating status of the system in real time and efficiently.

[0072] In order to solve the above technical problems, the present invention provides the following technical solutions: a transient analysis system for a gas-cooled reactor multi-component working fluid system, comprising: a data collection module, a control algorithm module, an equipment control module, a state display module and a learning optimization module;

[0073] The data collection module collects the operating status data of the new energy equipment and the grid voltage data in real time;

[0074] The control algorithm module is responsible for calculating the optimized equipment operation strategy based on the collected data to achieve collaborative work between devices;

[0075] The device control module sends control instructions to the new energy device according to the calculation results of the control algorithm module, so that the device operates according to the optimized strategy;

[0076] The status display module visualizes the equipment status and grid voltage status information so that operators can intuitively understand the current operating conditions;

[0077] The learning optimization module automatically learns and optimizes the control strategy of the equipment from historical data through a machine learning algorithm, thereby improving the effect and efficiency of grid voltage support.

[0078] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the transient analysis method of a multi-component working fluid system of a gas-cooled reactor are implemented.

[0079] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the transient analysis method for a gas-cooled reactor multi-component working fluid system as described above.

[0080] Beneficial effects of the present invention: The present invention provides a transient analysis method for a multi-component working fluid system of a gas-cooled reactor, which establishes a unified mass conservation equation for the mixture of multi-component working fluids in the system. It is not necessary to write conservation equations for each component separately, which simplifies the solution process and speeds up the calculation efficiency. At the same time, this method can be used to analyze the migration of each component working fluid in the circuit due to the flow of coolant. In addition, the proposed system transient analysis method takes into account the influence of the composition, concentration, and thermal parameters of the multi-component working fluid during its generation and migration on the thermal-hydraulic solution of the entire system. This method is in line with reality and ensures the accuracy of this method. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0082] Figure 1 An overall flow chart of a transient analysis method for a gas-cooled reactor multi-component working fluid system provided by the first embodiment of the present invention;

[0083] Figure 2 A structural diagram of a transient analysis method system for a gas-cooled reactor multi-component working fluid system provided by a second embodiment of the present invention;

[0084] Figure 3 A flowchart illustrating a transient analysis method for a multi-component working fluid system of a gas-cooled reactor provided in accordance with a third embodiment of the present invention. DETAILED DESCRIPTION

[0085] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0086] Example 1, reference Figure 1 According to an embodiment of the present invention, a transient analysis method for a gas-cooled reactor multi-component working fluid system is provided, comprising:

[0087] S1. First, it is necessary to determine the formation cause and location of the multi-component working fluid in the gas-cooled reactor.

[0088] The gas-cooled reactor system can be divided into a primary circuit including the core, hot gas duct, primary side of the steam generator, main helium blower, etc., and a secondary circuit including the secondary side of the steam generator, steam turbine, etc. There are different types of working fluids in the primary and secondary circuits of the system, which together form a multi-component working fluid situation of the system.

[0089] S2. Secondly, basic mathematical models for thermal-hydraulic analysis need to be established for the primary and secondary circuits of the system respectively.

[0090] S3. During the transient analysis of the system, thermal parameters will affect the formation of multi-component working fluids in the system, affecting the composition and concentration of the working fluids. At the same time, the heat released during the formation of the multi-component working fluids and the migration of the working fluids will also affect the thermal solution. Therefore, the transient analysis process of the multi-component working fluid system needs to deal with the above mutual influences through iterative solution.

[0091] Furthermore, step S1 is specifically as follows:

[0092] The common gas mixture in the primary loop of the gas-cooled reactor system is caused by graphite corrosion caused by an air intake accident. After a breach occurs in the pressure boundary of the primary loop of the system, the loop pressure is relieved to ambient pressure, the coolant helium is lost, and air enters the core to form a natural cycle. The air reacts chemically with graphite to form carbon monoxide, carbon dioxide, water vapor, hydrogen and other gases.

[0093] The main working fluid in the secondary circuit of the gas-cooled reactor system is water.

[0094] In a system where graphite corrosion is considered, possible working fluids may include helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, water vapor, water, and hydrogen.

[0095] The specific components of each working fluid need to be calculated through chemical reactions. The reaction rate of each chemical reaction is related to the concentration of each working fluid involved in the reaction, the reaction activation energy, the gas constant and the temperature. The concentration change rate of each working fluid can be obtained based on the chemical reaction rate.

[0096] Furthermore, step S2 is specifically as follows:

[0097] The coolant mixture in the primary circuit needs to satisfy the mass conservation of the various types of working fluids therein. In addition, in order to solve the system pressure field, the following mass conservation equation of the mixture is established.

[0098]

[0099] Among them, ε g is the gas fraction in the grid cell, ρ m is the coolant mixture density, t is the time, M o is the molecular weight of the coolant mixture, is the fluid flow rate, S m is the mass source term, is the cross derivative term due to the difference in molecular weight of the different gases in the coolant mixture.

[0100] It should be further explained that formula (1.1) is the mass conservation equation of the mixture constructed by treating the multiple working fluids as a whole mixture when there are multiple working fluids.

[0101] Among them, S Mo There are two solution methods.

[0102] Method 1: Assuming it is a uniform working fluid rather than a mixed working fluid, the mass conservation equation of the uniform working fluid is established as follows.

[0103]

[0104] Applying the differential product rule, using equations (1.1) and (1.2) together, we get expression.

[0105]

[0106] It should be further explained that method 1 is when there is only one working fluid, substitute the existing working fluid into formula (1.2), and use the simultaneous formula (1.1) and formula (1.2) to obtain

[0107] Method 2: Considering the conservation of mass of each working fluid, another method expressed by the molecular weight of each gas can be obtained. in the form of.

[0108] is the mole fraction, n i is the number of moles of different substances, is the molecular weight of the substance, then is the mass of a substance. The molar mass of the mixed working fluid is The density of the mixed working fluid is After combining

[0109] Assume that the different substances mix at a rate For convection, the mass conservation equation for each working fluid can be written as

[0110] Among them, S il is the mass exchange between substances, S i is the mass source term of the substance, is the constant of each substance, which can be calculated according to the equation To solve.

[0111] Therefore, the mass conservation equation of each working fluid can be written as:

[0112]

[0113] Then get The second expression of .

[0114]

[0115] It should be further explained that in method 2, each working fluid

[0116] To solve the mixed working fluid in a circuit, it is also necessary to establish the momentum conservation equation such as equation (1.6) and the energy conservation equation such as equation (1.7).

[0117]

[0118]

[0119] Where W is resistance, P is pressure, T g is the fluid temperature, λ g is the effective thermal conductivity of the fluid, α is the heat transfer coefficient between the solid and the fluid, α(T g -T s ) is the convective heat transfer term between the solid and the coolant gas, is the pressure gradient, is the acceleration due to gravity, is the fluid temperature gradient, c g is the specific heat capacity of the fluid.

[0120] The following basic mathematical model for thermal-hydraulic analysis is established for the working water in the secondary circuit.

[0121] The mass conservation equation:

[0122]

[0123] Energy conservation equation:

[0124]

[0125] Among them, m i is the mass of the working fluid in the control volume i, W i is the outlet mass flow rate of control body i, W i-1 is the outlet mass flow rate of control body i-1, τ is the time quantity, H i is the specific enthalpy of the working fluid in the control volume i, V i is the volume of control volume i, Q i In order to control the heat received by the working fluid in body i from the wall, P s For pressure.

[0126] Furthermore, the steam generator module adopts a fixed boundary, and the secondary side working fluid calculation adopts a constant volume condition, resulting in the following equation.

[0127]

[0128] Among them, i is the specific volume of control volume i.

[0129] The time derivative of specific volume in equation (1.10) is split into the time derivative of enthalpy and the time derivative of pressure, and then the equation written for constant volume conditions is converted into an equation containing enthalpy and pressure.

[0130] In the steam generator module, there are correlations between the parameters of the multi-component working fluids. The working fluid exchanges heat through the wall between the primary and secondary sides, and the water on the secondary side takes away the heat of the mixed working fluid on the primary side. The energy conservation equation of the mixed working fluid on the primary side is combined with the energy conservation equation of the wall surface to solve the heat transfer parameters on both sides.

[0131] Furthermore, step S3 is specifically as follows:

[0132] The specific steps of thermal hydraulic solution in transient analysis of a system with multi-component working fluids are as follows:

[0133] (1) Establish the basic mathematical model for thermal-hydraulic analysis of gas-cooled reactor system;

[0134] (2) Use staggered grids to divide the control volume and use the finite volume integration method to discretize the basic conservation equations;

[0135] (3) At the current temperature of each control body and assuming the mass flow rate of each control body, the mass conservation equation and momentum conservation equation of the working fluid are combined to obtain the pressure of each control body;

[0136] (4) Substitute the pressure of each control body into the mass conservation equation to obtain the updated value of the mass flow rate of each control body;

[0137] (5) Substitute the mass flow rate of each control body into the energy conservation equation to obtain the temperature of each control body;

[0138] (6) The control body temperature is judged to converge. If the temperature converges, proceed to step 7. Otherwise, repeat steps 3 to 5 until the temperature converges.

[0139] The temperature convergence criterion is:

[0140]

[0141] Among them, T k is the temperature value calculated for the kth time, T k+1 is the temperature value obtained by the k+1th calculation.

[0142] (7) Bring the current state parameters such as pressure, density, and temperature into the solution of the chemical reaction module to obtain the concentration of each working fluid under the current working conditions, and then calculate and feedback to obtain the new temperature value;

[0143] (8) Set the new temperature value as the current temperature and repeat steps 3-7 until the concentration of each component working fluid and the thermal characteristic parameters such as temperature, density, and pressure converge.

[0144] Example 2, reference Figure 2 , which is an embodiment of the present invention, provides a system for transient analysis method of a gas-cooled reactor multi-component working fluid system, including: a data collection module, a control algorithm module, a device control module, a state display module and a learning optimization module;

[0145] The data collection module collects the operating status data of new energy equipment and grid voltage data in real time;

[0146] The control algorithm module is responsible for calculating the optimized equipment operation strategy based on the collected data to achieve collaborative work between devices;

[0147] The equipment control module sends control instructions to the new energy equipment based on the calculation results of the control algorithm module, so that the equipment can operate according to the optimized strategy;

[0148] The status display module visualizes the equipment status and grid voltage status information, so that operators can intuitively understand the current operating conditions;

[0149] The learning optimization module uses machine learning algorithms to automatically learn and optimize the control strategy of equipment from historical data, thereby improving the effectiveness and efficiency of grid voltage support.

[0150] If the 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 software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0151] 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, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0152] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0153] 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.

[0154] Embodiment 3, Figure 3 This is another embodiment of the present invention. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments. This embodiment experiments the existing traditional method and the method of this embodiment respectively.

[0155] In the traditional solution method, the conservation equations of each working fluid need to be listed and solved separately. This method will consume a lot of computing cost when solving in a system with multiple components. Multiple iterative solutions are required in the system solution, such as Figure 3As shown in , the solution between pressure flow and temperature requires multiple iterations, and the chemical calculation and temperature calculation also require multiple iterations. Therefore, as the number of calculations accumulates, if each basic equation of the working fluid is solved separately, the number and speed of solutions will be greatly increased.

[0156] As shown in Table 1, the solution accuracy of the method of the present invention is basically consistent with that of the traditional method. The method of the present invention reasonably improves the solution model, and the convergence speed is much higher than that of the traditional method, which reduces the calculation cost and shortens the calculation time.

[0157] Table 1: Comparison table between traditional method and the method of the present invention

[0158] Convergence speed Accuracy Traditional methods Slow 98.14％ Method of the present invention 20% faster than traditional methods 98.13％

[0159] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A transient analysis method for a gas-cooled reactor multi-component working fluid system, characterized in that: include: Analyze the formation causes of multi-component working fluids in gas-cooled reactors and collect data for preprocessing; Construct mathematical models for thermal hydraulic analysis for the primary and secondary circuits of the system; Based on the constructed mathematical model of thermal hydraulic analysis, transient analysis of multi-component working fluids is carried out and the temperature of each control body is output.

2. A method for transient analysis of a gas-cooled reactor multi-component working fluid system according to claim 1, characterized in that: The analysis of the formation of multi-component working fluids in the gas-cooled reactor includes that the formation of a gas mixture in a primary loop of the gas-cooled reactor system is caused by graphite corrosion due to an air intake accident, and the working fluids present include helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, water vapor, water and hydrogen; The working fluid produced in the secondary circuit of the gas-cooled reactor system is water.

3. A method for transient analysis of a gas-cooled reactor multi-component working fluid system according to claim 2, characterized in that: The data include that the formation of the gas mixture in the primary loop of the gas-cooled reactor system is caused by graphite corrosion caused by the gas intake accident, and the working fluids present include helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, water vapor, water and hydrogen; The preprocessing is to calculate the specific components of each working fluid, the reaction rate of each chemical reaction and the change rate of each working fluid concentration according to the graphite corrosion phenomenon caused by the intake accident, and correct the data to delete abnormal values ​​to achieve consistency.

4. A method for transient analysis of a gas-cooled reactor multi-component working fluid system according to claim 3, characterized in that: The mathematical models for respectively constructing thermal hydraulic analysis include mass conservation equation, energy conservation equation, momentum conservation equation or pressure equation; The coolant mixture in the primary loop must satisfy the mass conservation of various types of working fluids that occur in the primary loop of the gas-cooled reactor system where graphite corrosion occurs. The system pressure field is solved and the mass conservation equation of the mixture is established. The expression is: Among them, ε g is the gas fraction in the grid cell, ρ m is the coolant mixture density, t is the time, M o is the molecular weight of the coolant mixture, is the fluid flow rate, S m is the mass source term, is the cross-derivative term due to the difference in molecular weight of different gases in the coolant mixture; To solve the mixed working fluid in a circuit, it is necessary to establish the momentum conservation equation and the energy conservation equation, and the expression is: Where W is resistance, P is pressure, T g is the fluid temperature, λ g is the effective thermal conductivity of the fluid, α is the heat transfer coefficient between the solid and the fluid, α(T g -T s ) is the convective heat transfer term between the solid and the coolant gas, is the pressure gradient, is the acceleration due to gravity, is the fluid temperature gradient, c g is the specific heat capacity of the fluid.

5. A method for transient analysis of a gas-cooled reactor multi-component working fluid system according to claim 4, characterized in that: The cross-derivative term generated by the difference in molecular weight of different gases includes two solutions; The first solution is to use the differential product rule to solve it. The mass conservation equation is established for the uniform working fluid. The expression is: Combined with the mass conservation equation of the mixture, the cross derivative term generated by the difference in molecular weight of different gases in the coolant mixture is obtained, and the expression is: The second solution is to solve the molar mass and density of the mixed working fluid by the molar fraction of each working fluid, and then output the total number of moles after combining them, which is expressed as: Where i is the i-th working fluid in the mixture, n i is the number of moles of working fluid i, are the molecular weight of working fluid i and the molar mass of the mixed working fluid, respectively. is the mass of the working fluid i, ρ m is the density of the mixed working fluid, ∑n i is the total number of moles, ε g is the gas fraction in the grid cell; Mixing speed between different working fluids For convection, the mass conservation equation for each working fluid is expressed as: Among them, S il is the mass exchange between the working fluids, S i is the mass source term of the working fluid, is a constant; Through algebraic transformation, it can be expressed as: The mass conservation equation of the mixed working fluid is expressed as: Among them, n i is the number of moles of working fluid i, is the fluid flow rate, S i is the mass source term of the working fluid, V is the volume, ρ m is the coolant mixture density.

6. A method for transient analysis of a gas-cooled reactor multi-component working fluid system according to claim 5, characterized in that: Establish a basic mathematical model for thermal hydraulic analysis of working water in the secondary circuit; The mass conservation equation is expressed as: The energy conservation equation is expressed as: Among them, m i is the mass of the working fluid in the control volume i, W i is the outlet mass flow rate of control body i, W i-1 is the outlet mass flow rate of control body i-1, τ is the time quantity, H i is the specific enthalpy of the working fluid in the control volume i, V i is the volume of control volume i, Q i In order to control the heat received by the working fluid in body i from the wall, P s For pressure; Using the fixed boundary method, the secondary side working fluid calculation adopts the constant volume condition, and the expression is: Among them, i is the specific volume of control volume i; The derivative of specific volume with respect to time is split into the derivative of enthalpy with respect to time and the derivative of pressure with respect to time, and the equation written under constant volume condition is converted into an equation containing enthalpy and pressure, which can be expressed as: The pressure equation is obtained: Among them, m i is the mass of the working fluid in the control volume i, υ i is the specific volume of control body i, H i is the specific enthalpy of the working fluid in the control volume i, P s For pressure.

7. A method for transient analysis of a gas-cooled reactor multi-component working fluid system according to claim 6, characterized in that: Outputting the temperature of each control body includes outputting the temperature of each control body and correlating the parameters between the multi-component working fluids, the working fluids exchange heat through the wall between the first and second circuits, the water on the secondary side takes away the heat of the mixed working fluid on the primary side, and the energy conservation equation of the mixed working fluid on the primary side is combined with the energy conservation equation of the wall surface to solve the heat exchange parameters on both sides; The control bodies are divided into staggered grids, and the basic conservation equations are discretized using the finite volume integration method. At the current temperature of each control body, under the assumption of the mass flow rate of each control body, the mass conservation equation and momentum conservation equation of the working fluid are combined to obtain the pressure of each control body. The pressure of each control body is substituted into the mass conservation equation to obtain the updated value of the mass flow rate of each control body. The mass flow rate of each control body is substituted into the energy conservation equation to obtain the temperature of each control body. The control body temperature is converged and the temperature convergence is added. If the temperature of the control body has completed convergence, the current thermal characteristic parameters pressure, density, and temperature are brought into the chemical reaction calculation to obtain the concentration of each working fluid under the current working condition, and then the new temperature value is obtained through calculation and feedback. The new temperature value is set as the current temperature, and the pressure of each control body, the updated value of the mass flow of each control body, and the temperature of each control body are repeatedly calculated until the concentration of each component working fluid and the temperature of the thermal characteristic parameters converge; If the temperature of the control body has not converged, the mass conservation equation and momentum conservation equation of the working fluid are repeatedly combined to output the pressure of each control body, the updated value of the mass flow rate of each control body, and the temperature of each control body until the temperature converges; The temperature converges, and the expression is: max|T k+1 -T k |≤1.0 -3 Among them, T k is the temperature value calculated for the kth time, T k+1 is the temperature value obtained by the k+1th calculation.

8. A system using a transient analysis method for a gas-cooled reactor multi-component working fluid system as claimed in any one of claims 1 to 7, characterized in that: It includes data collection module, control algorithm module, equipment control module, status display module and learning optimization module; The data collection module collects the operating status data of the new energy equipment and the grid voltage data in real time; The control algorithm module is responsible for calculating the optimized equipment operation strategy based on the collected data to achieve collaborative work between devices; The device control module sends control instructions to the new energy device according to the calculation results of the control algorithm module, so that the device operates according to the optimized strategy; The status display module visualizes the equipment status and grid voltage status information so that operators can intuitively understand the current operating conditions; The learning optimization module automatically learns and optimizes the control strategy of the equipment from historical data through a machine learning algorithm, thereby improving the effect and efficiency of grid voltage support.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of a transient analysis method for a gas-cooled reactor multi-component working fluid system according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a transient analysis method for a gas-cooled reactor multi-component working fluid system as described in any one of claims 1 to 7 are implemented.

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