Method for automatic water filling and reference volume establishment before reactor primary loop hydraulic test

Abstract

The application provides a method for automatic water filling and reference volume establishment before reactor primary loop hydraulic test, and relates to the technical field of reactor cooling, which comprises the following steps: collecting water flow related characteristic data in the primary loop, wherein the related characteristic data comprises water flow temperature, water flow pressure and water filling quality; pre-processing the related characteristic data to generate a water flow leakage deviation index; collecting related system parameters of gas, and then calculating a theoretical gas volume through the related system parameters and combining the theoretical gas volume with a measured gas volume to generate a gas leakage deviation index; setting a water flow leakage deviation threshold and a gas leakage deviation threshold, and combining the water flow leakage deviation index and the gas leakage deviation index to obtain a comprehensive leakage trend index; through the comprehensive leakage trend index, the application realizes accurate diagnosis of the sealing state of the primary loop and automatic identification of the leakage type, and significantly improves the safety, automation level and diagnosis reliability of the hydraulic test.

Description

Technical Field

[0001] This invention relates to the field of reactor cooling technology, specifically to a method for automatic water filling and reference volume establishment before a reactor primary circuit hydrostatic test. Background Technology

[0002] The reactor primary loop is one of the core systems of a nuclear power plant, carrying high-temperature and high-pressure coolant. Its integrity and sealing are directly related to nuclear safety and operational reliability. Before the primary loop is put into operation or after a major overhaul, a hydrostatic test must be conducted to verify the system's sealing performance and structural integrity under the design pressure, ensuring there are no leaks or potential defects. However, the thermal expansion and contraction effects caused by changes in water temperature and pressure are often ignored or simplified, resulting in a large deviation in the reference volume, which affects the accuracy of subsequent leak detection. Therefore, by integrating and analyzing multiple parameters such as temperature, pressure, water flow volume, and gas volume, a comprehensive leak index can be established for diagnosis, thereby automating, refining, and intelligentizing the preparation work before the hydrostatic test.

[0003] The prior art, disclosed in publication number CN116705355B, describes a method and system for filling the primary circuit with water after refueling during a nuclear power unit overhaul. This technology includes: performing preparatory work before filling; after completing the preparatory work, performing switching operation tests on the actuators to be tested and water filling and venting operations on the flowmeters; after completing the switching operation tests on the actuators to be tested, performing a performance test on the high-pressure safety injection pump; after completing the performance test on the high-pressure safety injection pump, performing a performance test on the low-pressure safety injection pump; after completing the performance test on the low-pressure safety injection pump, filling the primary circuit with water according to a preset filling mode; determining whether the real-time water level in the reactor pool has reached the full water level; if so, performing an alarm action test. By completing the preparatory work in advance and scheduling the alarm action test last, the problem of long processing time can be solved, the workload can be reduced, work efficiency can be significantly improved, work risks can be reduced, and production costs can be effectively saved.

[0004] However, the existing methods in the aforementioned technologies mostly rely on pressure gauge readings and manual observation, which are slow to respond to minor leaks and make it difficult to accurately identify and distinguish between water leaks and gas leaks in the early stages. They also lack continuous quantitative assessment and trend prediction of the leak status, making it difficult to support operators in making targeted intervention decisions. The water filling and monitoring processes still rely heavily on procedures and human experience, and have not formed a closed-loop automatic diagnosis and feedback mechanism. Therefore, there is an urgent need for a method that can automatically establish a high-precision volume reference during the water filling process, monitor and intelligently diagnose the primary loop sealing status in real time, so as to achieve a more reliable and efficient testing process.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an automated method for filling the primary circuit with water and establishing a reference volume before a reactor primary circuit hydrostatic test, thereby addressing the problems mentioned in the background section. This invention systematically collects multi-source characteristic data of water flow and gas, performs rigorous preprocessing and real-time fusion analysis, constructs a high-precision volume model, and calculates the leakage deviation indices of water flow and gas separately. Then, it combines adaptive thresholds to generate a comprehensive leakage trend index, achieving early and accurate diagnosis of the primary circuit sealing status and automatic identification of leakage types. This significantly improves the safety, automation level, and diagnostic reliability of the hydrostatic test.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An automatic water filling and reference volume establishment method for reactor primary circuit hydrostatic test includes the following steps:

[0009] S1: Collect water flow-related characteristic data within a loop, including water flow temperature, water flow pressure, and water filling mass;

[0010] S2: Preprocess the relevant feature data, including data validity verification, unit conversion, and timestamp synchronization to eliminate noise and ensure data consistency. Transform the original measured values ​​of the relevant feature data into data for calculation, establish a volume model, input the data into the volume model, and output the water flow volume. At the same time, obtain the initial reference water volume, combine the output water flow volume with the initial reference water volume to generate a water flow leakage deviation index, which is used to quantitatively characterize the degree of deviation of the current water flow volume from the normal sealing state.

[0011] S3: Collect relevant system parameters of the gas, including the real-time temperature of the gas, the pressure of the system, and the number of gas moles. The raw data of the relevant system parameters will be preprocessed to ensure their accuracy and consistency. Then, the theoretical gas volume is calculated through the relevant system parameters and combined with the measured gas volume to generate a gas leakage deviation index, which quantitatively characterizes the degree of deviation of the current gas volume from the normal sealing state.

[0012] S4: Set water flow leakage deviation threshold and gas leakage deviation threshold, and combine the water flow leakage deviation index and gas leakage deviation index with the water flow leakage deviation threshold and gas leakage deviation threshold to obtain a comprehensive leakage trend index. The comprehensive leakage trend index normalizes the complex water level and gas deviation data into a quantitative indicator and quantifies the severity of the anomaly. Based on the comprehensive leakage trend index, the sealing status in the primary loop is diagnosed to determine the leakage status of water flow and gas in the primary loop.

[0013] Furthermore, to ensure the accuracy of the reactor primary loop hydrostatic test and integrity assessment, it is necessary to systematically collect water flow-related characteristic data, including: water flow temperature, which is obtained by collecting redundant temperatures from the cold section, hot section, and pressurizer in the primary loop, and recording the trend of change over time; water flow pressure, which involves continuously monitoring the system operating pressure and pressurizer pressure, and correcting the obtained water flow pressure; and filling water mass, which is obtained by accumulating and verifying the total mass of demineralized water injected into the system, and after synchronous collection and verification, together constitute the input items for thermal-hydraulic calculations and leak diagnosis.

[0014] Furthermore, the collected relevant feature data undergoes systematic preprocessing. The preprocessing verifies and cleans the original measurement values ​​of the relevant feature data, eliminating invalid and outlier values ​​caused by instrument transient failures and communication interference. Interpolation is used to ensure data continuity. Subsequently, the data is uniformly converted into engineering physical quantities in standard international units. All data streams are time-stamped and resampled to eliminate analytical errors caused by asynchronous acquisition. Finally, a set of quality-marked and fully traceable computational data is generated.

[0015] Furthermore, the water leakage deviation index is calculated using the following formula:

[0016]

[0017] in: The initial reference water volume is derived from the water flow temperature, water flow pressure, and water filling mass during the initial water injection using a volume model.

[0018] The average thermal expansion coefficient of water;

[0019] This is the difference between the current average water temperature and the initial water temperature.

[0020] The current measured water volume is derived from the water flow temperature, water flow pressure, and water filling mass measured after time T.

[0021] This is the water leakage deviation index.

[0022] It provides a benchmark for water flow volume, and α and ΔT quantify the normal physical processes of thermal expansion and contraction of water flow. Reflecting the current water flow volume, the water flow leakage deviation index formula, by subtracting normal temperature effects, accounts for water loss. It stands out.

[0023] Furthermore, the volumetric model first receives water flow-related feature data within the primary loop. Simultaneously, based on the water temperature and pressure under the current operating conditions, the volumetric model calls the database in real time to obtain water density values ​​and dynamically corrects the volume of each partition. Subsequently, the volumetric model summarizes the calculation results of each partition and finally outputs a water flow volume that actually accommodates the water in the primary loop at the current moment.

[0024] Furthermore, during the preprocessing of the relevant system parameters of the gas, outlier removal and filtering are performed on the original signals of the relevant system parameters to eliminate transient interference; zero point, range and linearity corrections are performed according to the calibration certificate; data from different acquisition frequencies are synchronized to a unified time reference through timestamp alignment and interpolation; finally, the signal values ​​are converted into engineering values ​​in standard international units.

[0025] Furthermore, the gas leakage deviation index is calculated using the following formula:

[0026]

[0027] in: The initial number of gas moles is determined by the initial state;

[0028] The current system pressure and gas temperature;

[0029] The total geometric volume of the system is derived from the volume model.

[0030] This is the gas leakage deviation index.

[0031] Here is the formula for calculating the theoretical gas volume, where represents the value of the theoretical gas volume. This represents the measured gas volume.

[0032] Furthermore, in the formula for the gas leakage deviation index... Calculated system pressure based on current measurements and gas temperature The volume occupied by the gas is a theoretical prediction based on physical laws; it is the theoretical gas volume. According to the law of conservation of volume, the total volume of the system is... With the primary loop partially occupied by water, the remaining space in the primary loop is the volume actually occupied by the gas. The actual volume occupied by a gas based on geometric measurements is the measured gas volume.

[0033] Furthermore, the comprehensive leakage trend index is calculated using the following formula:

[0034]

[0035] in: This is a comprehensive leakage trend index;

[0036] A represents the water leakage deviation threshold;

[0037] B represents the gas leakage deviation threshold;

[0038] Furthermore, the comprehensive leakage trend index normalizes the measurement deviations of water flow volume and gas volume to generate a quantitative index. The comprehensive leakage trend index is directly related to the primary loop pressure change and is used to diagnose the sealing condition.

[0039] The comprehensive leakage trend index is used to explain the cause of pressure changes: when the system pressure changes, the comprehensive leakage trend index can be calculated to determine whether the pressure change is a normal change caused by thermal contraction due to water temperature changes, or an abnormal change caused by water or gas leakage; when the comprehensive leakage trend index is greater than zero, it indicates that the current pressure drop exceeds the expected range of thermal contraction, pointing to the presence of water leakage; when the comprehensive leakage trend index is less than zero, it indicates that the pressure drop points to the presence of gas leakage.

[0040] The Comprehensive Leakage Trend Index, as an integrated diagnostic signal, transforms general low pressure alarms into specific leak type judgments and indicates the severity of the anomaly, providing clear basis for operators to take targeted procedural actions.

[0041] Compared with existing technologies, the beneficial effects of this invention are: by systematically collecting multi-source characteristic data of water flow and gas, and through rigorous preprocessing and real-time fusion analysis, a high-precision volume model is constructed and water flow and gas leakage deviation indices are calculated separately. Then, combined with adaptive thresholds, a comprehensive leakage trend index is generated, realizing early and accurate diagnosis of the primary loop sealing status and automatic identification of leakage types, which significantly improves the safety, automation level and diagnostic reliability of hydrostatic testing. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the overall process flow of the automatic water filling and reference volume establishment method before the primary circuit hydrostatic test of the reactor according to the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0044] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0045] Example:

[0046] Please see Figure 1 The present invention provides a technical solution:

[0047] An automatic water filling and reference volume establishment method for reactor primary circuit hydrostatic test includes the following steps:

[0048] S1: Collect water flow-related characteristic data within a loop, including water flow temperature, water flow pressure, and water filling mass.

[0049] Establish a systematic and high-fidelity data acquisition system to obtain comprehensive and high-precision characteristic data of water flow, including the following relevant characteristic data:

[0050] First, the water flow temperature is measured by deploying multiple redundant temperature sensor arrays at key loop locations, including the cold and hot sections of each loop, the reactor pressure vessel outlet and inlet, the primary side chamber of the steam generator, and the pressurizer water section, to acquire spatially representative raw temperature data. Then, a weighted calculation is performed based on the water volume represented by each measurement point to obtain the volume-weighted average temperature reflecting the overall thermal state of the system. Continuously recording this average temperature and its gradient over time is fundamental for analyzing thermal expansion effects, calculating water density, and diagnosing thermal anomalies.

[0051] Secondly, there is the water flow pressure, which requires continuous and synchronous monitoring of the system's main operating pressure and the pressure regulator pressure. This eliminates the static water column pressure caused by the difference between the transmitter's installation height and the system reference point, ensuring that the final pressure value obtained is an absolute pressure value that reflects the true mechanical state of the system; water flow pressure is a direct input for solving water properties, analyzing system forces, and judging leaks.

[0052] Finally, there is the water filling quality, which is the benchmark for water volume calculation. It is necessary to use high-precision measurement methods to cumulatively measure and independently verify the demineralized water injected into the system. Usually, a calibrated mass flow meter is used for main measurement, and cross-verification is carried out simultaneously through the liquid level-volume change of the capacity control tank to accurately obtain and repeatedly verify the total mass of demineralized water injected into the system. This is the absolute benchmark for subsequent calculation of the system's baseline volume and water quality balance analysis.

[0053] S2: Perform a rigorous, systematic, and auditable full-process preprocessing on the collected relevant feature data. Preprocessing is a key bridge connecting the raw measurement signals and advanced analysis models. Its core objective is to transform the collected raw data into high-quality information that can be used for precise calculations.

[0054] Preprocessing begins with rigorous data validity verification and deep cleaning. The system first performs logical and physical limit checks on the raw measurements of relevant feature data, automatically identifying and removing invalid values ​​and statistical outliers caused by instrument transient failures, channel interference, or communication packet loss. For non-critical transient gaps in the key parameter sequence, robust interpolation algorithms are used to fill them in based on the data trends of preceding and following time periods, ensuring the continuity and integrity of the data sequence and laying the foundation for subsequent trend analysis.

[0055] Subsequently, a signal standardization conversion based on metrological traceability is performed. Based on the independent and valid calibration certificates of each sensor and transmitter involved in the measurement, the raw output signals are converted one by one into engineering physical quantities in standard international units. This is not only a unification of units, but also a process of tracing the measured values ​​to national or international standards. This eliminates the systematic deviation caused by the instrument's own error and ensures that all data are based on recognized and consistent measurement benchmarks.

[0056] Subsequently, precise time base alignment and data stream synchronization are performed. Due to the diverse data sources and varying acquisition cycles, a high-precision time clock must be used to uniformly calibrate, synchronize, and resample all independent data streams. By interpolating or aggregating the data from each channel onto a unified, equally spaced time series grid, the phase difference and causal misjudgment caused by asynchronous acquisition are fundamentally eliminated. This allows the changes in different physical quantities to be accurately correlated and analyzed on the time axis, which is crucial for capturing transient processes and performing multi-parameter coupled calculations.

[0057] Ultimately, a standardized dataset with a complete quality profile is generated. Each data point is labeled with a clear quality tag and associated with the corresponding original data record, the applied calibration coefficient, the processing algorithm identifier, and the operation log. This forms a set of fully traceable and highly consistent final calculation data, which can be directly used for thermal-hydraulic modeling and leak diagnosis. The complete preprocessing profile also provides a solid chain of evidence for the authority of the data, the verifiability of the calculation results, and the quality assurance of the entire experimental process.

[0058] The water leakage deviation index is calculated using the following formula:

[0059]

[0060] in: The initial reference water volume is given at the initial steady-state moment of the experiment. The total volume of water that fills the primary loop system, which has been precisely measured, is obtained by inputting the accumulated total mass of water into the volume model, combined with the water density determined by the initial state of water flow temperature and pressure.

[0061] The average thermal expansion coefficient of water is the relative rate of change of water volume when the temperature changes by 1°C at a specific temperature and pressure. It is obtained by referring to the international standard physical property table based on the current water flow temperature and pressure.

[0062] It is the difference between the current average water temperature and the initial water temperature, that is, the change in the volume-weighted average temperature of the water in the system from the initial time t0 to the current time t.

[0063] The actual water volume is the volume of water in the first loop obtained from time T to the current time (t). It is usually obtained after density correction based on the total mass of water filling and the current water flow temperature and pressure.

[0064] The water leakage deviation index;

[0065] It provides a benchmark for water flow volume, and α and ΔT quantify the normal physical processes of thermal expansion and contraction of water flow. Reflects the current water flow volume; the water flow leakage deviation index formula, by subtracting the normal temperature effect, accounts for water loss. It stands out;

[0066] To quantitatively correct for the thermal expansion and contraction effect, α is the coefficient of thermal expansion of water, and ΔT is the change in current water temperature relative to the initial water temperature. When the water temperature rises, the water expands and its volume is expected to increase; when the water temperature falls, the water contracts and its volume is expected to decrease.

[0067] The volumetric model has dynamic property coupling capability. For each independent calculation zone, the model will call the embedded or connected international water vapor property standard database in real time based on the current water temperature and system pressure of that zone, and obtain the accurate water density value under specific thermodynamic conditions through precise interpolation calculation. Then, the volumetric model will first convert the water level height measured in each zone into an uncorrected geometric volume by combining the precise three-dimensional geometric dimensions, and then apply the above real-time density value to perform volume conversion, thereby obtaining the equivalent volume of water contained in that zone under the current operating conditions, thus correcting the influence of water density changes caused by changes in water temperature and pressure on volume measurement.

[0068] After completing the independent calculation and dynamic correction of all partitions, the model performs data reduction and summarization, integrates the equivalent volumes calculated from all partitions, and outputs a total instantaneous flow volume of the entire loop after final consistency verification.

[0069] S3: Collect relevant system parameters of the gas, including the real-time temperature of the gas, the pressure of the system, and the number of gas moles. The raw data of the relevant system parameters will undergo data preprocessing. First, the raw signal sequence will be automatically identified and eliminated by outliers, and combined with digital filtering algorithms to eliminate high-frequency noise and pulse interference introduced by electromagnetic transients, brief instrument abnormalities, or signal transmission disturbances, so as to ensure the physical rationality of the data sequence.

[0070] Then, zero-point offset correction, range scaling and nonlinearity compensation are performed on the original output of the relevant system parameters, which is the key to converting the instrument signal into a physical quantity with a clear metrological traceability chain and eliminating system errors during data acquisition.

[0071] Since different parameter acquisition systems may have different sampling frequencies and communication delays, high-precision timestamp alignment of multiple data streams is necessary. By interpolating or resampling each data sequence onto a unified, equally spaced, high-precision time axis, strict temporal consistency of parameters such as pressure and temperature can be ensured at any analysis point. This is a prerequisite for causal analysis and accurate transient process modeling.

[0072] Finally, the corrected and synchronized signal values ​​are converted into engineering values ​​that can be directly used for scientific calculations according to the International System of Units (SI). The fundamental purpose of preprocessing is to comprehensively improve the quality of the raw data in terms of accuracy, temporal consistency, and physical reliability. This results in high-standard time series data.

[0073] The gas leakage deviation index is calculated using the following formula:

[0074]

[0075] in: The initial number of gas moles is determined by the initial state. If the value is too large, the theoretical volume of the entire calculation will be systematically higher, and the gas leakage deviation index will also be larger, causing the gas leakage deviation index to remain positive and forming a false leakage signal.

[0076] Given the current system pressure and gas temperature, an increase in system pressure will decrease the theoretical gas volume, thus decreasing the gas leakage deviation index and causing it to tend towards a negative value; an increase in gas temperature will increase the theoretical gas volume, thus increasing the gas leakage deviation index and causing it to tend towards a positive value.

[0077] The total geometric volume of the system is derived from the volume model and represents the fixed geometric space within a single loop.

[0078] This refers to the gas leakage deviation index;

[0079] Here is the formula for calculating the theoretical gas volume, where represents the value of the theoretical gas volume. This represents the measured gas volume.

[0080] The calculation of theoretical gas volume is based on classical thermodynamics principles, expressed as follows: Strictly adhering to the ideal gas law, its physical meaning is: assuming at the initial reference time... Afterwards, the gas space of the pressure regulator remains completely sealed, meaning the number of moles of gas inside is constant and always equal to the initial value. Then, the absolute pressure of the system measured at the current time (t) is... With absolute temperature of gas Below, the volume occupied by these gas molecules according to the laws of physics; therefore, The value is a purely theoretical prediction, reflecting how the gas volume should change with pressure and temperature under ideal conditions of no leakage and conservation of mass. The key input for the calculation is real-time measurement. and and accurately calibrated initial constants and universal gas constant .

[0081] The calculation of the measured gas volume is based on the fundamental fact of geometric volume conservation. For a reactor primary loop with a defined structure, the total volume consisting of all internal pipes and containers is calculated. It is a fixed geometric constant, and at any given time, its interior is filled with only two media: liquid water and gas. The current water volume is calculated by real-time monitoring of the water level and using the water density corrected for temperature and pressure. So, from a fixed total volume After deducting the portion occupied by water, the remaining space is the actual physical volume occupied by the gas. Essentially, it is an inferred value based on direct geometric measurements, objectively reflecting the actual spatial size of the gas within the system. Its accuracy directly depends on the total volume. The accuracy of the calibration and the water volume Reliability of the measurement.

[0082] The theoretical prediction value and the measured gas volume value are compared, that is, the difference is calculated. This forms the cornerstone of gas leak diagnosis. If the gas behavior matches the expected behavior of the sealing system, it proves that the gas behavior is in line with the expectations of the sealing system. If there is a significant deviation, it clearly indicates that the gas mass is no longer conserved.

[0083] S4: The comprehensive leakage trend index is calculated using the following formula:

[0084]

[0085] in: This is a comprehensive leakage trend index;

[0086] A represents the water leakage deviation threshold;

[0087] B represents the gas leakage deviation threshold;

[0088] The water leakage deviation index is positively correlated with the comprehensive leakage trend index. When the water leakage deviation index increases, the comprehensive leakage trend index will increase, making the comprehensive leakage trend index tend to be greater than zero. The gas leakage deviation index is negatively correlated with the comprehensive leakage trend index. When the water leakage deviation index increases, the comprehensive leakage trend index will decrease, making the comprehensive leakage trend index tend to be less than zero.

[0089] In a reactor primary loop leakage monitoring system, scientifically setting water leakage deviation thresholds and gas leakage deviation thresholds is crucial for distinguishing between normal system fluctuations and actual anomalies. The determination of these thresholds is primarily based on a combined uncertainty analysis of the entire measurement and calculation chain, encompassing the inherent errors of all instruments, the calculation biases of the physical property model, and the inherent background noise of the system. Beyond this technical benchmark, a safety-oriented conservative margin is further added, and multiple alarm levels are often established to balance early warning requirements with operational stability. The water leakage deviation threshold considers the impact of representative temperature measurement errors on thermal expansion calculations, while the gas leakage deviation threshold considers the deviation of ideal gases and the propagation effect of water volume measurement errors. Ultimately, the thresholds must be rigorously verified using historical data and simulated operating conditions, and used as dynamically manageable parameters for review and adjustment during system changes, thereby ensuring that leakage diagnosis achieves an optimal balance between sensitivity and reliability.

[0090] The comprehensive leakage trend index is a core quantitative indicator in the online diagnostic system for the primary loop sealing condition. Through a standardized algorithm, the water leakage deviation index and the gas leakage deviation index are normalized, calculated, and fused to generate a single, continuous, and real-time trackable quantitative index. The fundamental value of the comprehensive leakage trend index lies in its establishment of a direct and quantitative physical correlation with the pressure changes in the primary loop system. This allows the change of pressure, a comprehensive state parameter, to be analyzed into a distinguishable and specific physical cause, thus achieving accurate diagnosis of the system's sealing integrity.

[0091] The core diagnostic function of the Comprehensive Leakage Trend Index is to act as a decoupler for the causes of pressure changes. When a drop in system pressure is detected, operators face a critical judgment: is this drop an expected normal thermal transient, or does it indicate a dangerous leakage event? The Comprehensive Leakage Trend Index answers this question directly through its calculation logic. The Comprehensive Leakage Trend Index has an embedded thermal-hydraulic model that can quantify the expected thermal contraction effect. By comparing the actual pressure drop with the pressure drop predicted solely by thermal contraction, the Comprehensive Leakage Trend Index can separate out the abnormal pressure loss portion.

[0092] When the comprehensive leakage trend index is significant and consistently greater than zero, it indicates that there is an additional pressure loss in the system that cannot be explained by thermal contraction. This clearly points to a leak in the primary loop water medium. The leakage of water directly reduces the total amount of medium in the system and causes the gas expansion to be unable to fully compensate, resulting in an abnormal pressure drop. The positive value of the comprehensive leakage trend index can indirectly reflect the relative severity and development rate of the leak.

[0093] When the comprehensive leakage trend index is significant and consistently less than zero, it indicates that the main driver of the pressure drop is not water loss. This usually strongly indicates that gas is leaking in the pressurizer gas space. When gas leaks, the dynamic response of the pressure drop is much faster and more significant than that of water leakage. The comprehensive leakage trend index issues an alarm by capturing this characteristic deviation pattern.

[0094] The comprehensive leakage trend index surpasses simple threshold alarms. Through an integrated value, it transforms the phenomenon of pressure drop into a specific fault mode of water or gas leakage in real time, providing operators with accurate operational decision-making basis. It is a key technical tool for achieving predictive maintenance and early and accurate intervention in accidents.

[0095] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0096] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0097] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0098] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor, characterized in that, Includes the following steps: S1: Collect water flow-related characteristic data within a loop, including water flow temperature, water flow pressure, and water filling mass; S2: Preprocess the relevant feature data, including data validity verification, unit conversion, and timestamp synchronization to eliminate noise and ensure data consistency. Transform the original measured values ​​of the relevant feature data into data for calculation, establish a volume model, input the data into the volume model, and output the water flow volume. At the same time, obtain the initial reference water volume, combine the output water flow volume with the initial reference water volume to generate a water flow leakage deviation index, which is used to quantitatively characterize the degree of deviation of the current water flow volume from the normal sealing state. S3: Collect relevant system parameters of the gas, including the real-time temperature of the gas, the pressure of the system, and the number of gas moles. The raw data of the relevant system parameters will be preprocessed to ensure their accuracy and consistency. Then, the theoretical gas volume is calculated through the relevant system parameters and combined with the measured gas volume to generate a gas leakage deviation index, which quantitatively characterizes the degree of deviation of the current gas volume from the normal sealing state. S4: Set water flow leakage deviation threshold and gas leakage deviation threshold, and combine the water flow leakage deviation index and gas leakage deviation index with the water flow leakage deviation threshold and gas leakage deviation threshold to obtain a comprehensive leakage trend index. The comprehensive leakage trend index normalizes the complex water level and gas deviation data into a quantitative indicator and quantifies the severity of the anomaly. Based on the comprehensive leakage trend index, the sealing status in the primary loop is diagnosed to determine the leakage status of water flow and gas in the primary loop.

2. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: The system collects water flow-related characteristic data to ensure the accuracy of the reactor primary loop hydrostatic test and integrity assessment. This includes: water flow temperature, which is obtained by collecting redundant temperatures from the cold section, hot section, and pressurizer in the primary loop, and recording the trend of change over time; water flow pressure, which is continuously monitored by monitoring the system operating pressure and pressurizer pressure, and the obtained water flow pressure is corrected; and filling water mass, which is accumulated and verified by accumulating the total mass of demineralized water injected into the system. After synchronous collection and verification, these data constitute the input items for thermal-hydraulic calculations and leak diagnosis.

3. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: The collected relevant feature data undergoes systematic preprocessing. The preprocessing verifies and cleans the original measured values ​​of the relevant feature data, removing invalid and outlier values ​​caused by instrument transient failures and communication interference. Interpolation is used to ensure data continuity. Subsequently, the data is uniformly converted into engineering physical quantities in standard international units. All data streams are time-stamped and resampled to eliminate analytical errors caused by asynchronous acquisition. Finally, a set of quality-marked, fully traceable computational data is generated.

4. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: The water leakage deviation index is calculated using the following formula: in: The initial reference water volume is derived from the water flow temperature, water flow pressure, and water filling mass during the initial water injection using a volume model. The average thermal expansion coefficient of water; This is the difference between the current average water temperature and the initial water temperature. The current measured water volume is derived from the water flow temperature, water flow pressure, and water filling mass measured after time T. The water leakage deviation index; It provides a benchmark for water flow volume, and α and ΔT quantify the normal physical processes of thermal expansion and contraction of water flow. Reflecting the current water flow volume, the water flow leakage deviation index formula, by subtracting normal temperature effects, accounts for water loss. It stands out.

5. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: The volumetric model first receives water flow-related feature data within the primary loop. Simultaneously, based on the water temperature and pressure under the current operating conditions, the volumetric model calls the database in real time to obtain water density values ​​and dynamically corrects the volume of each partition. Subsequently, the volumetric model summarizes the calculation results of each partition and finally outputs a water flow volume that actually accommodates the water in the primary loop at the current moment.

6. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: When preprocessing the relevant system parameters of the gas, outlier removal and filtering are performed on the original signals of the relevant system parameters to eliminate transient interference; zero point, range and linearity are corrected according to the calibration certificate; data from different acquisition frequencies are synchronized to a unified time base through timestamp alignment and interpolation; finally, the signal values ​​are converted into engineering values ​​in standard international units.

7. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: The gas leakage deviation index is calculated using the following formula: in: The initial number of gas moles is determined by the initial state; The current system pressure and gas temperature; The total geometric volume of the system is derived from the volume model. This refers to the gas leakage deviation index; Here is the formula for calculating the theoretical gas volume, where represents the value of the theoretical gas volume. This represents the measured gas volume.

8. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 7, characterized in that: In the formula for the gas leakage deviation index Calculated system pressure based on current measurements and gas temperature The volume occupied by the gas is a theoretical prediction based on physical laws; it is the theoretical gas volume. According to the law of conservation of volume, the total volume of the system is... With the primary loop partially occupied by water, the remaining space in the primary loop is the volume actually occupied by the gas. The actual volume occupied by a gas based on geometric measurements is the measured gas volume.

9. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 1, characterized in that: The comprehensive leakage trend index is calculated using the following formula: in: This is a comprehensive leakage trend index; A represents the water leakage deviation threshold; B represents the gas leakage deviation threshold.

10. The method for automatic water filling and reference volume establishment before the primary circuit hydrostatic test of a reactor according to claim 9, characterized in that: The comprehensive leakage trend index normalizes the measurement deviations of water flow volume and gas volume to generate a quantitative index. The comprehensive leakage trend index is directly related to the pressure change of the primary loop and is used to diagnose the sealing condition. The comprehensive leakage trend index is used to explain the cause of pressure changes: when the system pressure changes, the comprehensive leakage trend index can be calculated to determine whether the pressure change is a normal change caused by thermal contraction due to water temperature changes, or an abnormal change caused by water or gas leakage; when the comprehensive leakage trend index is greater than zero, it indicates that the current pressure drop exceeds the expected range of thermal contraction, pointing to the presence of water leakage; when the comprehensive leakage trend index is less than zero, it indicates that the pressure drop points to the presence of gas leakage. The comprehensive leakage trend index transforms general low pressure alarms into specific leakage type judgments, indicating the severity of the anomaly.

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