Method and system for combined measurement of flow rate and temperature in a primary circuit of a nuclear power plant

Abstract

This invention provides a method and system for combined measurement of primary loop flow and temperature in nuclear power plants. A measuring mechanism is installed at the interface to be measured in the main pipeline, causing flow-sound resonance within the primary loop flow velocity range. Then, the real-time flow velocity and temperature values ​​of the primary loop medium are calculated using data acquisition and processing equipment. Compared with traditional flow velocity and temperature measurement methods, this invention reduces the restrictions on the installation location of the measuring mechanism, reduces the number of openings by 2 / 3, thereby reducing the number of primary loop pressure boundary welds, eliminating the need for temperature measuring inserts in the main pipeline, and reducing the risk of foreign object intrusion into the primary loop.

Description

Technical Field

[0001] This invention relates to the field of safety design technology for reactor coolant systems in nuclear power plants, specifically to a method and system for combined measurement of primary loop flow and temperature in a nuclear power plant. Background Technology

[0002] Multiple flow and temperature sensors are installed on the main pipeline of the reactor coolant system in nuclear power plants to monitor the flow and operating status of the primary coolant. The measurement signals are linked to the safety monitoring system, and an automatic reactor shutdown is triggered when an anomaly is detected. Therefore, the accuracy of the measurement plays an important role in maintaining the safe operation of the reactor.

[0003] Because the primary loop pressure boundary safety requirements are extremely high, and the primary loop medium has the characteristics of high temperature, high pressure, and high radiation, common volumetric flow meters, velocity flow meters, electromagnetic flow meters, etc. are not suitable for primary loop flow measurement.

[0004] Currently, most primary loop flow meters in nuclear power plants use bend flow meters. These meters utilize the pressure difference that forms between the inside and outside of the bend when fluid flows through it. The differential pressure is linearly related to the average flow velocity, and the flow rate is calculated by measuring the pressure difference.

[0005] Bend flow meters have advantages such as no pressure loss and strong environmental adaptability, but they also have many limitations. For example, there are requirements for the design of the bend structure. If the radius is too large, it will affect the measurement accuracy. In addition, bend flow meters need to set two pressure taps on the inside and outside of the bend, which increases the number of openings and welds at the primary circuit pressure boundary and increases the risk of primary circuit coolant leakage.

[0006] Temperature measurement in the primary loop of nuclear power plants often uses insertion-type RTD sensors. The thermometer sheath needs to be inserted into the main pipeline, which may disturb the local flow field in the main pipeline. In addition, under the scouring of high-speed fluid, there is a possibility of fatigue fracture failure, which increases the risk of foreign object intrusion in the primary loop.

[0007] Based on this, the inventors of this application propose a method and system for combined measurement of primary loop flow and temperature in nuclear power plants, in order to solve one or more of the aforementioned technical problems. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, such as high restrictions on the installation location of primary loop flow and temperature measurement, large number of primary loop openings, and inclusion of primary loop inserts, and to provide a method and system for composite measurement of primary loop flow and temperature in nuclear power plants.

[0009] The present invention solves the above-mentioned technical problems through the following technical solution:

[0010] This invention provides a method for combined measurement of primary loop flow and temperature in a nuclear power plant, comprising:

[0011] Step 1: Set up a measuring mechanism at the interface to be tested of the main pipeline; wherein, the measuring mechanism includes at least one branch pipe, and a vibration signal measuring sensor is provided at the end of the branch pipe away from the main pipeline to be tested;

[0012] Step 2: Measure the vibration time history of each branch pipe end using a data acquisition and processing device that is communicatively connected to the vibration signal measurement sensor, and determine the target branch pipe in the acoustic resonance state based on the vibration time history data;

[0013] Step 3: Perform Fourier transform on the maximum vibration time history using the data acquisition and processing device to obtain the real-time vibration spectrum. Extract the frequency domain peak vibration intensity and the corresponding peak frequency based on the real-time vibration spectrum. At the same time, calculate the average vibration intensity in a specific frequency range outside the acoustic resonance interval.

[0014] Step 4: Calculate the sound velocity of the medium using the peak frequency, the peak vibration intensity in the frequency domain, and the average vibration intensity.

[0015] Step 5: Calculate the real-time medium temperature and real-time medium density based on the sound velocity of the medium and the real-time pressure of the power plant's primary circuit safety monitoring system.

[0016] Step 6: Calculate the real-time Strohal number based on the frequency domain peak vibration intensity and the average vibration intensity.

[0017] Step 7: Calculate the real-time flow velocity of the main pipeline using the Strouhal number and the peak frequency;

[0018] Step 8: Calculate the real-time volumetric flow rate of the main pipeline using the inner diameter of the main pipeline and the real-time flow velocity, and calculate the mass flow rate of the main pipeline based on the volumetric flow rate and the real-time medium density.

[0019] According to one embodiment of the present invention, the longest branch pipe in step 1 is provided with an enlarged diameter pipe.

[0020] According to one embodiment of the present invention, the vibration signal measurement sensor in step 2 is connected to a data analysis and processing device via a signal connection cable;

[0021] The data analysis and processing equipment is communicatively connected to the power plant's primary circuit safety monitoring system.

[0022] According to an embodiment of the present invention, in step 3, the maximum value of the Y-axis is extracted from the real-time vibration spectrum as the peak vibration intensity in the frequency domain, the corresponding X-axis value is extracted as the peak frequency, and all Y values ​​in a specific frequency range outside the X-axis resonance interval are averaged to obtain the average value of the turbulent vibration intensity that increases with the increase of the flow velocity.

[0023] According to one embodiment of the present invention, in step 4, the formula for calculating the speed of sound is:

[0024] C = (4L + 0.6d) * f;

[0025] Where C is the sound velocity of the medium in the main pipeline to be measured, L is the corrected equivalent length between the inner wall of the main pipeline to be measured and the inner wall of the closed end of the target branch pipe, d is the inner diameter of the target branch pipe, and f is the peak frequency of the target branch pipe.

[0026] The target branch is an acoustic resonance branch.

[0027] According to one embodiment of the present invention, when the target branch pipe is provided with an expanded diameter pipe, the acoustic diaphragm frequency of the acoustic cavity structure is obtained through acoustic simulation analysis, and the equivalent length between the inner wall of the main pipe to be tested and the inner wall of the closed end of the target branch pipe is corrected.

[0028] According to an embodiment of the present invention, in step 5, the real-time medium temperature and real-time medium density are calculated using the medium sound velocity and the real-time pressure of the power plant primary circuit safety monitoring system, based on the international standard IAPWS-IF97 formula.

[0029] According to an embodiment of the present invention, in step 6, the real-time Strohal number is obtained through a calibrated curve relating acoustic resonance intensity to Strohal number; wherein, the curve relating acoustic resonance intensity to Strohal number is:

[0030] ;

[0031] Where a is the frequency domain peak vibration intensity. The average vibration intensity For Strohal numbers.

[0032] According to an embodiment of the present invention, in step 7, the formula for calculating the real-time flow velocity of the main pipeline is:

[0033] ;

[0034] Where f is the peak frequency, and d is the inner diameter of the target branch pipe. For Strohal numbers.

[0035] According to one embodiment of the present invention, after step 8, the method further includes:

[0036] Step 9: Transmit the main pipeline flow and temperature data to the power plant's primary circuit safety monitoring system.

[0037] A computer program product according to a second aspect of this application includes a computer program that, when executed by a processor, implements the steps performed by a computer as described in the first aspect.

[0038] According to a third aspect of this application, a computer-readable storage medium has a computer program that, when executed by a processor, implements the steps performed by a computer as described in the first aspect.

[0039] A measurement system according to a fourth aspect of this application includes: a memory capable of storing instructions executable by a processor; and a processor capable of executing the instructions to perform the steps performed by a computer as described in the first aspect.

[0040] The positive and progressive effects of this invention are as follows:

[0041] This invention relates to a method for combined measurement of primary loop flow and temperature in nuclear power plants. A measuring mechanism is installed at the interface to be measured in the main pipeline, causing flow-sound resonance within the primary loop flow velocity range. The real-time flow velocity and temperature values ​​of the primary loop medium are then calculated using data acquisition and processing equipment. Compared with traditional flow velocity and temperature measurement methods, this invention reduces the restrictions on the installation location of the measuring mechanism, reduces the number of openings by 2 / 3, thereby reducing the number of primary loop pressure boundary welds, eliminating the need for temperature measuring inserts in the main pipeline, and reducing the risk of foreign object intrusion into the primary loop. Attached Figure Description

[0042] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0043] Figure 1 This is a schematic diagram illustrating the principle of flow resonance.

[0044] Figure 2 This is a schematic diagram of the arrangement of the measuring mechanism of the present invention;

[0045] Figure 3 This is a schematic diagram of the vibration spectrum processing of the present invention;

[0046] Figure 4 This is a schematic diagram showing the relationship between the acoustic resonance intensity and the Strouhal number of this invention.

[0047] Figure 5 This is a flowchart of the method for combined measurement of primary loop flow and temperature in a nuclear power plant according to the present invention.

[0048] Figure 6 This is a schematic diagram of the measurement system of the present invention.

[0049] 1. Main pipeline to be tested; 11. Interface to be tested;

[0050] 2. First branch pipe;

[0051] 3. Second branch pipe;

[0052] 4. Third branch pipe;

[0053] 5. Expanded diameter pipe;

[0054] 6. Vibration signal measurement sensor;

[0055] 7. Connect the cables;

[0056] 8. Data acquisition and processing equipment;

[0057] 9. Power plant primary circuit safety monitoring system; 91. Pressure data input channel; 92. Flow and temperature data output channel. Detailed Implementation

[0058] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0059] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are illustrated in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts. Furthermore, although the terminology used herein is selected from commonly known and used terminology, some terms mentioned in this specification may have been chosen by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of the description herein. Moreover, the invention should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0060] The principle of this invention for calculating flow rate and temperature based on the vibration signal of branch pipe flow acoustic resonance is as follows:

[0061] According to the quarter-wavelength theory, the sound frequency of a stagnant branch pipe is related to the length of the stagnant pipe and the sound velocity of the medium. Therefore, after measuring the vibration frequency of the branch pipe and knowing its length, the sound velocity of the medium can be calculated. The sound velocity of the medium is related to its temperature and pressure; therefore, the temperature of the medium can be calculated using the sound velocity and the measured pressure value.

[0062] Reference Figure 1 According to the theory of flow resonance, when high-speed fluid flows through the stagnant branch pipe opening in the main pipeline, shear layer separation occurs, generating eddies without a specific frequency, thus creating broadband turbulent excitation. Within a certain velocity range, the eddy frequency is locked by the stagnant pipe acoustic frequency, forming pressure pulsations at a specific frequency, i.e., flow resonance occurs. Figure 1This is a diagram illustrating the principle of flow-sound resonance. After entering the flow-sound coupling region, the sound resonance intensity gradually increases with the increase of flow velocity, reaches a peak, and then gradually decreases until it leaves the flow-sound coupling resonance region. Therefore, the flow velocity of the main pipeline can be calculated from the sound vibration frequency and vibration intensity.

[0063] Based on this, the present invention proposes a method for combined measurement of primary loop flow and temperature in a nuclear power plant, comprising:

[0064] Step 1: Set up a measuring mechanism at the interface to be tested of the main pipeline; wherein, the measuring mechanism includes at least one branch pipe, and a vibration signal measuring sensor is provided at the end of the branch pipe away from the main pipeline to be tested.

[0065] Reference Figure 2 , Figure 2 A schematic diagram of the measuring mechanism is shown. Furthermore, Figure 2 The number of branch pipes is illustrated using three as an example. However, the number of branch pipes can be one, two, or more; there is no limitation here, and it can be set according to actual needs. As for the vibration signal measurement sensor, it can be a conventional vibration sensor, including but not limited to acceleration sensors, velocity sensors, displacement sensors, or even dynamic pressure sensors; the specific type is not limited here.

[0066] Specifically, the measuring mechanism includes the main pipe to be measured 1, the first branch pipe 2, the second branch pipe 3, the third branch pipe 4, the expansion pipe 5, three vibration signal measuring sensors 6, connecting cables 7, data acquisition and processing equipment 8, the power plant primary circuit safety monitoring system 9, pressure data input channel 91, and flow and temperature data output channel 92. Among them, the expansion pipe 5 is installed on the first branch pipe 2.

[0067] The main pipe 1 under test has one test interface 11 on its straight section. One end of a branch pipe is connected to the main pipe 1 under test by welding. The first branch pipe 2, the second branch pipe 3, and the third branch pipe 4 have different lengths. The first branch pipe 2 is the longest and is used to form flow acoustic resonance in the low flow velocity range. The second branch pipe 3 is of medium length and is used to form flow acoustic resonance in the medium flow velocity range. The third branch pipe 4 is the shortest and is used to form flow acoustic resonance in the high flow velocity range. An expansion pipe 5 is installed on the first branch pipe 2, but the number of expansion pipes 5 is not limited to one and can be installed on the first branch pipe 2, the second branch pipe 3, and the third branch pipe 4 respectively.

[0068] Vibration signal measurement sensors 6 are installed at the ends of the first branch pipe 2, the second branch pipe 3, and the third branch pipe 4 that are away from the main pipe 1 to be tested. The vibration signal measurement sensors 6 are used to measure the vibration response at the ends of the branch pipes. The vibration signal measurement sensors 6 are connected to the data acquisition and processing equipment 8 through the signal connection cable 7. The data acquisition and processing equipment 8 is used for data acquisition and to calculate the temperature and flow data of the medium in the main pipe using the acquired data.

[0069] The data acquisition and processing device 8 obtains real-time pressure data from the power plant primary circuit safety monitoring system 9 through the pressure data input channel 91, and outputs real-time flow and temperature data to the power plant primary circuit safety monitoring system 9 through the flow and temperature data output channel 92.

[0070] It should be noted that, Figure 2 The example uses three branch pipes, but the specific number is not limited. Different numbers of branch pipes can be selected for measurement as needed.

[0071] Step 2: Measure the vibration time history of each branch pipe end using a data acquisition and processing device that is connected to the vibration signal measurement sensor, and determine the target branch pipe in the acoustic resonance state based on the vibration time history data.

[0072] It can be seen that the kinetic energy of the fluid in the resonant branch forms a positive feedback loop with the sound pressure oscillation energy and the vibration energy of the pipe wall, and the energy continues to accumulate. Therefore, the branch corresponding to the data with the largest vibration intensity is the target branch, which also corresponds to the branch that resonates.

[0073] Therefore, the target branch pipe in the acoustic resonance state can be determined based on the vibration time history data.

[0074] Step 3: Perform Fourier transform on the maximum vibration time history using data acquisition and processing equipment to obtain the real-time vibration spectrum. Extract the frequency domain peak vibration intensity and corresponding peak frequency based on the real-time vibration spectrum. At the same time, calculate the average vibration intensity of a specific frequency range outside the acoustic resonance interval.

[0075] In other words, the maximum vibration time history corresponds to the branch pipe signal with the strongest acoustic resonance energy. Selecting this signal for Fourier transform ensures that the amplitude of the acoustic resonance frequency is much higher than the background noise, and avoids interference from low-energy signals from other non-resonant branches in frequency domain feature extraction. Moreover, performing Fourier transform only on the highest energy signal reduces the amount of data processing and meets real-time measurement requirements.

[0076] Specifically, regarding vibration time history and vibration intensity, depending on the type of vibration signal measurement sensor, an accelerometer can obtain a time history curve of acceleration changing with time, and the processed vibration intensity is the acceleration amplitude; a velocity sensor can obtain a time history curve of velocity changing with time, and the processed vibration intensity is the velocity amplitude; a displacement sensor can obtain a time history curve of displacement changing with time, and the processed vibration intensity is the displacement amplitude; and a dynamic pressure sensor can obtain a time history curve of pressure pulsation changing with time, and the processed vibration intensity is the pressure pulsation amplitude.

[0077] This application uses the acceleration time history measured by an accelerometer and the acceleration amplitude obtained by processing it as an example for illustration, but does not limit it.

[0078] For details, please refer to Figure 3 , Figure 3 The diagram illustrates the vibration spectrum processing. The maximum value on the Y-axis is extracted as the peak vibration intensity in the frequency domain, and the corresponding X-axis value is extracted as the peak frequency f. The average vibration intensity is obtained by averaging all Y-axis values ​​outside the X-axis resonance interval (55-70Hz in this example). .

[0079] Step 4: Calculate the sound velocity of the medium using the peak frequency, the peak vibration intensity in the frequency domain, and the average vibration intensity.

[0080] According to the theory of flow resonance, the relationship between sound frequency and flow velocity can be expressed by the following formula:

[0081] (1)

[0082] Wherein, d is the inner diameter of the branch pipe opening, which is selected according to the layout conditions of the main pipeline. In this invention, a DN25 branch pipe is preferred, which can reduce the size of the primary loop break while forming flow sound resonance. In other optional implementation scenarios, branch pipes of other diameters can also be selected, which are not limited here. This indicates the flow velocity in the main pipeline. Based on the design flow velocity range of the primary loop, the measurement range of the flow velocity can be determined. The Strohal number is a dimensionless number used to describe the mechanism of oscillating flow. It is related to parameters such as the fluid Reynolds number and the pipe diameter ratio of the branch pipe to the main pipe. Flow resonance will occur in the range of approximately 0.2 to 0.6.

[0083] It should be noted that, The acoustic frequency of a stagnant branch, for a single stagnant branch, can be expressed by the following formula according to the quarter-wavelength theory:

[0084] (2)

[0085] in, The sound velocity of the medium in the main pipeline to be tested can be calculated based on the design temperature and pressure range of the primary loop, using the international standard IAPWS-IF97 formula and the thermodynamic properties of water and water vapor, to determine the sound velocity range of the primary loop medium. L is the length from the inner wall of the main pipeline to the inner wall of the closed end of the branch pipe, calculated according to formula (1) to satisfy the flow resonance. Required ,according to Calculate the required branch pipe length using C.

[0086] That is, in formula (1), d is a constant value, and v is the design velocity range of the primary loop. Given the range of values, the range of values ​​for f can be calculated from this.

[0087] In formula (2), C is the range of sound velocity of the medium in the main pipeline, d is a constant value, and f is the range value obtained by formula (1). Thus, the numerical range of L can be calculated according to formula (2). Then, the extreme values ​​at both ends of the range and the middle value can be selected as the required length of the branch pipe. After obtaining the length of the branch pipe, the measuring mechanism can be designed.

[0088] It should be noted that the flow velocity range of a typical main pipeline is 0~25m / s, and a single stagnant branch pipe structure is insufficient to cover the required flow velocity range. Therefore, a multi-mode acoustic branch pipe structure with different frequencies is designed to allow different branch pipes to form acoustic resonance in different flow velocity ranges. The nth-order acoustic mode frequency of the multi-branch structure is... It can be expressed by the following formula:

[0089] (3)

[0090] in, This represents the distance from the inner wall of the closed end of the nth branch pipe to the inner wall of the main pipe, from longest to shortest.

[0091] As can be seen, the number of branches can be increased or decreased according to the required range. For example, an expansion tube can be added to the branch to act as a Helmholtz resonant cavity, thereby reducing the acoustic frequency of the branch and thus covering a wider frequency range.

[0092] Since the acoustic frequency is mainly related to the length of the branch pipe, the direction of the branch pipe can be adjusted by adding bends or elbows according to the actual layout space. Then, finite element analysis software such as ANSYS can be used to obtain a more accurate acoustic modal frequency through simulation analysis, and the equivalent length can be obtained by correcting the calculation results. .

[0093] After completing the acoustic cavity structure design, it is necessary to calculate and verify the branch structure modes to avoid the structure's natural frequency falling within the acoustic resonance frequency range, which would interfere with the measurement.

[0094] Due to the formation of flow resonance The range is related to parameters such as the fluid Reynolds number and the pipe diameter ratio of the branch pipe to the main pipe. Furthermore, the acoustic resonance intensity is related to the actual stiffness and damping of the pipe structure. Therefore, after the measuring agency completes its design, manufacturing, and installation, it is necessary to measure and calibrate the branch pipe vibration at different flow velocities, and obtain an accurate acoustic resonance intensity through fitting. The relationship curve is shown in equation (4).

[0095] (4)

[0096] in, This represents the peak acoustic resonance intensity in the frequency domain after performing a Fourier transform on the vibration time history.

[0097] It is the average vibration intensity, representing the average vibration intensity in a specific frequency range outside the acoustic resonance interval in the frequency domain. It is used to characterize the non-resonant turbulent vibration that increases with increasing flow velocity. Eliminating the effects of turbulent vibrations that increase with flow velocity, thereby accurately reflecting The relationship with acoustic resonance intensity.

[0098] Please refer to Figure 4 , Figure 4 A schematic diagram showing the relationship between acoustic resonance intensity and Strouhal number is presented, with vibration intensity measured at different flow velocities. and Accurate results can be obtained through fitting. and The relationship curve.

[0099] Step 5: Based on the sound velocity of the medium and the real-time pressure calculation of the power plant's primary circuit safety monitoring system, the real-time medium temperature and real-time medium density are obtained.

[0100] Specifically, based on the international standard IAPWS-IF97 formula, the real-time medium temperature and real-time medium density are calculated using the medium sound velocity and the real-time pressure of the power plant's primary circuit safety monitoring system.

[0101] It should be noted that, according to the international standard IAPWS-IF97 formula, the method of determining the medium temperature and density from the known sound velocity and pressure values ​​is a well-known technique in the art and will not be elaborated here.

[0102] For example, at temperature T: the sound speed equation is solved iteratively. Solve for the following: where p represents pressure and T represents temperature; calculate temperature T using a linker iteration or bisection method; and calculate density ρ using the following formula: Where g is the Gibbs free energy and P is the pressure.

[0103] Step 6: Calculate the real-time Strouhal number based on the peak vibration intensity and the average vibration intensity in the frequency domain.

[0104] That is, based on the frequency domain peak vibration intensity 'a' and the reference vibration intensity (Average vibration intensity), determined by the calibrated acoustic resonance intensity and... The relationship curve, i.e., formula (4), is used to obtain real-time data. value.

[0105] Step 7: Calculate the real-time flow velocity of the main pipeline using the Strohal number and peak frequency.

[0106] Specifically, the formula for calculating the flow velocity in the main pipeline is:

[0107] v=f*d / ;

[0108] Where f is the peak frequency and d is the inner diameter of the target branch pipe. For Strohal numbers.

[0109] Step 8: Calculate the real-time volumetric flow rate of the main pipeline using the inner diameter of the main pipeline and the real-time flow velocity, and calculate the mass flow rate of the main pipeline based on the volumetric flow rate and the real-time medium density.

[0110] In other words, the cross-sectional area of ​​the main pipe can be calculated using its inner diameter, and the volumetric flow rate of the main pipe can be obtained by multiplying the cross-sectional area by the real-time volumetric flow rate. The mass flow rate of the main pipe can be obtained by multiplying the volumetric flow rate of the main pipe by the real-time medium density.

[0111] Please refer to the following: Figure 5 , Figure 5 The flowchart of the measurement method proposed in this invention is shown, and the specific steps are as follows:

[0112] 1. Use vibration signal measurement sensors to measure the vibration time history at the ends of each branch pipe and read the primary circuit pressure. Determine the target branch pipe in the acoustic resonance state based on the magnitude of the vibration intensity.

[0113] 2. Using data analysis and processing equipment, perform Fourier transform on the maximum vibration time history and primary loop pressure to obtain the real-time vibration spectrum, identify the frequency f of the frequency domain peak vibration intensity, and identify the frequency a of the frequency domain peak vibration intensity and the reference vibration intensity. ;

[0114] 3. Based on the real-time acoustic vibration frequency f and the equivalent length of the branch n in the acoustic resonance state. The real-time medium sound velocity is calculated using the above formula (3). ;

[0115] 4. Based on the speed of sound Real-time pressure provided by the primary loop safety monitoring system The real-time medium temperature T is calculated using the international standard IAPWS-IF97 formula and other methods, and the real-time medium density ρ is also calculated.

[0116] 5. Based on frequency domain peak vibration intensity 'a' and average vibration intensity Through the calibrated acoustic resonance intensity and The relationship curve, i.e., the above formula (4), is used to obtain real-time data. value;

[0117] 6. Based on The value is calculated using the formula (1) above to determine the real-time flow velocity of the main pipeline. ;

[0118] 7. Based on the inner diameter of the main pipe and the real-time flow velocity Calculate the real-time volumetric flow rate based on the real-time medium density. Calculate the mass flow rate.

[0119] Therefore, this invention, based on the principle of acoustic resonance, can be installed on straight pipe sections. Compared with traditional bent pipe flow meters, it reduces the restrictions on installation location conditions and does not have requirements on the structural design of the main pipeline to be measured, such as the bend radius.

[0120] This invention requires only one interface to measure flow rate and temperature. Traditional bend flow meters require two pressure tapping openings on the upper and lower surfaces of the bend, and the thermometer sleeve requires an additional opening, for a total of three openings. This invention only requires one opening, reducing the number of primary circuit pressure boundary welds and lowering the risk of primary circuit coolant leakage.

[0121] Meanwhile, this invention eliminates the need to insert the main pipe under test, thus solving the drawbacks of traditional temperature measurement using insertion-type RTD sensors, including potential disturbances to the local flow field of the main pipe under test and the risk of fatigue fracture failure of the insert under the scouring of high-speed fluid, which could lead to foreign object intrusion in the primary loop.

[0122] refer to Figure 6 As shown, this application also provides a control system 1000, including a memory 1001 and a processor 1002. The memory is capable of storing instructions that can be executed by the processor 1002. The processor 1002 is capable of executing instructions to implement the steps performed by the computer in the nuclear power plant primary loop flow and temperature composite measurement method described in the above embodiments.

[0123] It is understood that the aforementioned memory and processor are not limited to a specific memory or processor. Furthermore, in embodiments employing a distributed architecture, the specific execution terminal for each step can be adjusted according to actual circumstances, and the specific implementation scheme of each step on a particular terminal should not limit the scope of protection of this application.

[0124] According to another aspect of this application, a computer-readable medium is also provided.

[0125] The computer-readable medium provided in this application has computer instructions thereon. When executed by a processor, these computer instructions can implement the steps performed by the program in the methods described in the above embodiments.

[0126] According to another aspect of this application, a computer program product is also provided.

[0127] The computer-readable medium provided in this application includes a computer program that, when executed by a processor, can implement the steps performed by the program in the method described in the above embodiments.

[0128] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, it may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0129] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor such that the processor can read and write information to / from the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0130] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functionality may be stored or transmitted as one or more instructions or code on or via a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used in this article, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

[0131] While this application discloses preferred embodiments as described above, it is not intended to limit the scope of this application. Any changes and modifications can be made by those skilled in the art without departing from the spirit and scope of this application. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall fall within the protection scope defined by the claims of this application.

Claims

1. A method for combined measurement of primary loop flow and temperature in a nuclear power plant, characterized in that, include: Step 1: Set up a measuring mechanism at the interface to be tested of the main pipeline; wherein, the measuring mechanism includes at least one branch pipe, and a vibration signal measuring sensor is provided at the end of the branch pipe away from the main pipeline to be tested; Step 2: Measure the vibration time history of each branch pipe end using a data acquisition and processing device that is communicatively connected to the vibration signal measurement sensor, and determine the target branch pipe in the acoustic resonance state based on the vibration time history data; Step 3: Perform Fourier transform on the maximum vibration time history using the data acquisition and processing device to obtain the real-time vibration spectrum. Extract the frequency domain peak vibration intensity and the corresponding peak frequency based on the real-time vibration spectrum. At the same time, calculate the average vibration intensity in a specific frequency range outside the acoustic resonance interval. Step 4: Calculate the sound velocity of the medium using the peak frequency, the peak vibration intensity in the frequency domain, and the average vibration intensity. Step 5: Calculate the real-time medium temperature and real-time medium density based on the sound velocity of the medium and the real-time pressure of the power plant's primary circuit safety monitoring system. Step 6: Calculate the real-time Strohal number based on the frequency domain peak vibration intensity and the average vibration intensity. Step 7: Calculate the real-time flow velocity of the main pipeline using the Strouhal number and the peak frequency; Step 8: Calculate the real-time volumetric flow rate of the main pipeline using the inner diameter of the main pipeline and the real-time flow velocity, and calculate the mass flow rate of the main pipeline based on the volumetric flow rate and the real-time medium density.

2. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, The longest branch pipe in step 1 is equipped with an enlarged diameter pipe.

3. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, The vibration signal measurement sensor in step 2 is connected to the data analysis and processing equipment via a signal connection cable. The data analysis and processing equipment is communicatively connected to the power plant's primary circuit safety monitoring system.

4. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, In step 3, the maximum value of the Y-axis is extracted from the real-time vibration spectrum as the peak vibration intensity in the frequency domain, the corresponding X-axis value is extracted as the peak frequency, and all Y values ​​in a specific frequency range outside the X-axis resonance interval are averaged to obtain the average value of the turbulent vibration intensity that increases with the flow velocity.

5. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, In step 4, the formula for calculating the speed of sound is: C = (4L + 0.6d) * f; Where C is the sound velocity of the medium in the main pipeline to be measured, L is the corrected equivalent length between the inner wall of the main pipeline to be measured and the inner wall of the closed end of the target branch pipe, d is the inner diameter of the target branch pipe, and f is the peak frequency of the target branch pipe. The target branch is an acoustic resonance branch.

6. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 5, characterized in that, When the target branch pipe is equipped with an expansion pipe, the acoustic diaphragm frequency of the acoustic cavity structure is obtained through acoustic simulation analysis, and the equivalent length between the inner wall of the main pipe under test and the inner wall of the closed end of the target branch pipe is corrected.

7. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, In step 5, the real-time medium temperature and real-time medium density are calculated using the medium sound velocity and the real-time pressure of the power plant's primary circuit safety monitoring system, based on the international standard IAPWS-IF97 formula.

8. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, In step 6, the real-time Strohal number is obtained through the calibrated relationship curve between acoustic resonance intensity and Strohal number; wherein, the relationship curve between acoustic resonance intensity and Strohal number is as follows: ； Where a is the frequency domain peak vibration intensity. The average vibration intensity For Strohal numbers.

9. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, In step 7, the formula for calculating the real-time flow velocity in the main pipeline is: v=f*d / ; Where f is the peak frequency, and d is the inner diameter of the target branch pipe. For Strohal numbers.

10. The method for combined measurement of primary loop flow and temperature in a nuclear power plant according to claim 1, characterized in that, The process after step 8 also includes: Step 9: Transmit the main pipeline flow and temperature data to the power plant's primary circuit safety monitoring system.

11. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the steps performed by a computer in the method as described in any one of claims 1-10.

12. A computer-readable storage medium, characterized in that, The method comprises a computer program that, when executed by a processor, implements the steps performed by a computer in the method as described in any one of claims 1-10.

13. A measurement system, characterized in that, include: Memory is capable of storing instructions that can be executed by a processor; A processor capable of executing the instructions to implement the steps performed by a computer in the method as described in any one of claims 1-10.

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