Reactor building pressure boundary low-pressure rapid leakage detection method and device

Abstract

The invention belongs to the field of nuclear power station performance tests, and particularly relates to a reactor building pressure boundary low-pressure rapid leakage detection method and device, and the method comprises the steps: 1, presetting a leakage rate reference limit value, setting a signal sampling period, carrying out the boosting of a reactor building, and uninterruptedly collecting the internal physical parameters of the reactor building in real time; 2, establishing pressure for the first time, calculating an instantaneous predicted leakage rate by adopting a sliding window method, and comparing the instantaneous predicted leakage rate with a preset leakage rate in real time; and 3, establishing the pressure for the second time, calculating the leakage rate in unit time, constructing a differential pressure-leakage rate relation model based on the least square method, and calculating the leakage rate under the specified pressure. According to the method, the instantaneous prediction leakage rate can be obtained in real time, meanwhile, the measurement condition can be met under the conditions that the pressure cannot be maintained and the pressure disturbance is large, an accurate measurement result is obtained, rapid measurement is achieved, and the measurement speed is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear power plant performance tests, and particularly relates to a method and device for rapidly detecting low-pressure leakage of the pressure boundary of a reactor building. Background Art

[0002] The main function of the reactor building of advanced nuclear power technology (referred to as "reactor building" for short) is to prevent radioactive substances from being released into the surrounding environment under design basis accidents, and it is the last physical barrier to implement the principle of nuclear power's multi-layered defense. In order to ensure public safety, it is necessary to detect its leakage rate to evaluate whether its sealing performance meets the design requirements.

[0003] The current technical solution mainly includes the following steps: (1) pressurize to the test pressure; (2) after the inside is fully static and the air is stable, maintain it at this pressure platform for 24 hours and select stable data points; (3) calculate the leakage rate (% / 24h) according to the ideal gas state equation. The main defects of this technical solution are: (1) On the one hand, when detecting, a ventilation system is required to maintain the operation of the internal system, and it is difficult to obtain a stable static pressure under wind disturbance, resulting in the inability to quickly judge the leakage rate, bringing difficulties to the work of plugging leaks and eliminating defects, and increasing the waiting time of staff in the radiation environment; (2) On the other hand, compared with the traditional containment leakage rate detection, its leakage rate magnitude is significantly increased, which is reflected in the inability to maintain a certain pressure for a long time for detection. If the detection result is not ideal or it is difficult to meet the measurement conditions, it will cause a significant increase in the detection time, repeated tests, and even problems such as the inability to carry out the internal work of the reactor building, seriously affecting the project progress.

[0004] Therefore, there is an urgent need to develop a method and device for rapidly detecting low-pressure leakage of the pressure boundary of a reactor building to measure the leakage rate of an advanced reactor building with a large low-pressure volume and no steel lining where the leakage rate index is above 1% / 24h. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and device for rapidly detecting low-pressure leakage of the pressure boundary of a reactor building, which can obtain the instantaneous predicted leakage rate in real time, and at the same time can meet the measurement conditions under the situation of unable to maintain pressure and large pressure disturbances, obtain accurate measurement results, and achieve rapid measurement, effectively improving the measurement speed, and is applicable to detecting the leakage rate of an advanced reactor building with a large low-pressure volume and no steel lining where the leakage rate index is above 1% / 24h.

[0006] The technical solution to achieve the purpose of the present invention: A method for rapidly detecting low-pressure leakage of the pressure boundary of a reactor building, the method includes: Step 1: Preset the leakage rate reference limit value, set the signal sampling period, boost the pressure of the reactor building, and collect the internal physical parameters of the reactor building in real time and continuously; Step 2: Establish the pressure for the first time, calculate the instantaneous predicted leakage rate using the sliding window method, and compare the instantaneous predicted leakage rate with the preset leakage rate in real time; Step 3: Establish the pressure for the second time, calculate the leakage rate per unit time, construct a differential pressure - leakage rate relationship model based on the least - squares method, and calculate the leakage rate at the specified pressure.

[0007] Furthermore, the internal physical parameters of the reactor building collected in Step 1 include: absolute pressure, ambient temperature, relative humidity, differential pressure.

[0008] Furthermore, the formula for calculating the instantaneous predicted leakage rate in Step 2 is: In the formula, L is the instantaneous predicted leakage rate, unit: % / 24h; P n is the absolute pressure at the n th moment, unit: kPa; P n-i is the absolute pressure at the n-i th moment, unit: kPa, i is the time coefficient, which converts the selected time period into unit time.

[0009] Furthermore, the real - time comparison of the instantaneous predicted leakage rate and the preset leakage rate in Step 2 includes: if the instantaneous predicted leakage rate is greater than the preset leakage rate value, the pressure boundary of the reactor building should be checked for leaks and defects eliminated until the instantaneous predicted leakage rate is lower than the preset leakage rate value.

[0010] Furthermore, after the pressure is established for the first time in Step 2, when the pressure of the reactor building rises to the detection pressure, if the pressure of the reactor building is lower than the detection pressure, continue to supplement the pressure increase.

[0011] A low - pressure rapid leakage detection device for the pressure boundary of a reactor building, the device includes: an instantaneous leakage rate prediction unit, a leakage rate measurement unit, and a computer; the instantaneous leakage rate prediction unit and the leakage rate measurement unit are connected to the computer input interface; the instantaneous leakage rate prediction unit measures the absolute pressure inside the reactor building and transmits the absolute pressure measurement data to the computer; the leakage rate measurement unit measures the internal pressure, differential pressure, ambient temperature, and relative humidity of the reactor building and transmits the pressure, differential pressure, ambient temperature, and relative humidity measurement data to the computer; the computer processes the absolute pressure measurement data and the pressure, differential pressure, ambient temperature, and relative humidity measurement data to calculate the instantaneous predicted leakage rate and the leakage rate at the detection pressure.

[0012] Furthermore, the instantaneous leakage rate prediction unit includes: a mobile pressure filtering device and an absolute pressure gauge. The mobile pressure filtering device is arranged at a position inside the reactor building away from wind disturbance. The absolute pressure gauge is pneumatically connected to the mobile pressure filtering device and electrically connected to a computer. The mobile pressure filtering device is used to filter the dynamic pressure to obtain a stable pressure. The absolute pressure gauge measures the absolute pressure and transmits the absolute pressure measurement data to the computer, and the computer processes the absolute pressure measurement data to calculate the instantaneous predicted leakage rate.

[0013] Furthermore, the absolute pressure gauge is a high-precision absolute pressure gauge with a measuring range of 80 - 120 kPa and an accuracy of 0.01% F.S.

[0014] Furthermore, the leakage rate measurement unit includes: a mobile pressure filtering device, a signal acquisition instrument, a pressure gauge, a differential pressure gauge, a temperature sensor, and a humidity transmitter; The mobile pressure filtering device is arranged at a position inside the reactor building away from wind disturbance, and the temperature sensor and the humidity transmitter are arranged inside the reactor building; The pressure gauge is pneumatically connected to the mobile pressure filtering device and electrically connected to a computer. The mobile pressure filtering device is used to filter the dynamic pressure to obtain a stable pressure. The pressure gauge measures the pressure and transmits the pressure measurement data to the computer; One end of the pneumatic path of the differential pressure gauge is connected to the mobile pressure filtering device, and the other end communicates with the atmosphere; the electrical circuit is connected to a computer. The differential pressure gauge measures the differential pressure data and transmits the differential pressure measurement data to the computer; The temperature sensor and the humidity transmitter are respectively connected to the signal acquisition instrument, and the signal acquisition instrument is connected to a computer. The temperature sensor measures the internal environmental temperature of the reactor building and transmits the environmental temperature measurement data to the computer through the signal acquisition instrument; the humidity transmitter measures the relative humidity inside the reactor building and transmits the relative humidity measurement data to the computer through the signal acquisition instrument; The computer processes the pressure, differential pressure, environmental temperature, and relative humidity measurement data, uses the measured pressure, environmental temperature, and relative humidity data, and calculates the leakage rate according to the ideal gas state equation; according to the differential pressure and the calculated leakage rate, a differential pressure - leakage rate relationship model is used for linear fitting to calculate the leakage rate under a specified pressure.

[0015] Furthermore, a three-way pressure measuring port is provided inside the mobile pressure filtering device, and the pneumatic paths of the absolute pressure gauge, the pressure gauge, and the differential pressure gauge are respectively connected to the three-way pressure measuring port through pressure guiding hoses.

[0016] The beneficial technical effects of the present invention are as follows: 1. A method for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention calculates the pressure change rate per unit time by using the sliding window method, which has strong real-time performance and can calculate the pressure change rate in real time (preferably once every 3 seconds), realizes the real-time acquisition of the instantaneous predicted leakage rate, can timely detect and eliminate leaks in the pressure boundary of the reactor building, and effectively reduces the leakage amount of radioactive substances; and by using the sliding window method to calculate the pressure change rate per unit time (in the embodiment, it is calculated by sliding the data of 1 minute), it can ensure that the obtained instantaneous leakage rate is more accurate.

[0017] 2. A method for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention constructs a differential pressure-leakage rate relationship model by maintaining pressure and based on the least squares method, which can effectively solve the problem of "it is difficult to maintain a certain pressure for a long time and it is difficult to meet the measurement conditions due to the increase in the order of magnitude of the leakage rate", and can accurately obtain the leakage rate result under the specified pressure.

[0018] 3. A device for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention can quickly measure and obtain a stable static pressure through a mobile pressure filtering device and an absolute pressure gauge; combined with the method of obtaining the instantaneous predicted leakage rate in real time, it can realize the rapid evaluation of the leakage rate.

[0019] 4. A method for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention combines the calculation of the instantaneous predicted leakage rate (step 2) and the calculation of the leakage rate (step 3) for leakage detection. Compared with the existing leakage detection methods, it can meet the measurement conditions and obtain accurate measurement results under the conditions of unable to maintain pressure and large pressure disturbances. Due to (dynamic) pressure disturbances, the superimposed pressure drops too fast to maintain the test pressure, and the existing measurement methods cannot establish the test conditions and the test cannot be carried out. The present invention uses the sliding window method to calculate the instantaneous predicted leakage rate (step 2), combines with the pressure filtering device, and can quickly measure the stable static pressure; uses the least squares method to construct a differential pressure-leakage rate relationship model to calculate the leakage rate under the specified pressure (step 3), and can measure the accurate leakage rate under the specified pressure under the condition of unable to maintain the test pressure.

[0020] 5. A method for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention combines the calculation of the instantaneous predicted leakage rate (step 2) and the calculation of the leakage rate (step 3) for leakage detection. Compared with the existing leakage detection methods, it can effectively improve the measurement speed and facilitate leakage detection. With the existing detection methods, it takes 24 hours of pressure holding to obtain the leakage rate. If there is a leakage, it is necessary to check for and fill the leak, and then hold the pressure for another 24 hours. The detection time is long and the efficiency is slow. The present invention combines the calculation of the instantaneous predicted leakage rate and the calculation of the leakage rate. First, a prediction is made within a short period of time. If the requirements are not met, leakage detection can be carried out immediately (step 2) (qualitative first). After the leakage detection is completed, precise calculation is carried out (step 3) (quantitative second), which can greatly shorten the detection time, improve the efficiency, and quickly give a conclusion without changing the accuracy level of the result. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a device for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention.

[0022] In the figure: 101 - reactor building; 102 - computer; 1 - mobile pressure filter device; 2 - absolute pressure gauge; 3 - pressure guiding hose; 4 - three-way pressure measuring port; 5 - signal collector; 6 - pressure gauge; 7 - differential pressure gauge; 8 - temperature sensor; 9 - humidity transmitter; 10 - signal cable. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0024] A method for rapid low-pressure leakage detection of the pressure boundary of a reactor building provided by the present invention specifically includes the following steps: Step 1: Preset the leakage rate reference limit value, set the signal sampling period, boost the pressure of the reactor building, and collect the internal physical parameters of the reactor building in real time and continuously; The collected physical parameters include: absolute pressure, ambient temperature, relative humidity, differential pressure.

[0025] Step 2: Establish the pressure for the first time. According to the absolute pressure inside the reactor building, use the sliding window method to calculate the instantaneous predicted leakage rate, and compare the instantaneous predicted leakage rate with the preset leakage rate in real time; When the pressure in the reactor building rises to the detection pressure and remains static for a period of time, the sliding window method is used to calculate the pressure reduction rate per unit time, and the relative pressure change rate can be indirectly obtained. This relative pressure change rate is the instantaneous predicted leakage rate. This instantaneous predicted leakage rate is dynamically updated and compared with the preset leakage rate in real time: If the instantaneous predicted leakage rate is greater than the preset leakage rate value, the pressure boundary of the reactor building should be checked for leaks and defects eliminated until the instantaneous predicted leakage rate is lower than the preset leakage rate value. At this time, if the pressure in the reactor building is lower than the detection pressure, the pressure should be replenished and raised continuously.

[0026] Among them, the pressure reduction rate is the pressure change per unit time, and the unit is: kPa / unit time.

[0027] The calculation formula for using the sliding window method to calculate the pressure reduction rate per unit time is: In the formula, P is the pressure change rate, unit: kPa / h; P n is the absolute pressure at the n moment, unit: kPa; P n-i is the absolute pressure at the n-i moment, unit: kPa, i is the time coefficient, which converts the selected time period into unit time (per hour).

[0028] For example, when using the sliding window method to calculate the pressure reduction rate per hour, the sliding window calculation is performed every 3 seconds, then the window data volume per minute is 20, and the calculation formula for the pressure reduction rate is: In the formula, P is the pressure change rate, unit: kPa / h; P n is the absolute pressure of the first number in the window, unit: kPa; P n-20 is the absolute pressure at the end in the window (the 20th number), unit: kPa; 60 is converted to per hour, unit: hour.

[0029] According to the pressure reduction rate, calculate the relative pressure change rate within 24 hours. This relative pressure change rate is the instantaneous predicted leakage rate value. That is: The relative pressure change rate and the sequential predicted leakage rate are basically the same. Calculate the instantaneous relative pressure change rate, and the leakage rate can be known. The calculation formula for the instantaneous predicted leakage rate is: In the formula, L is the instantaneous predicted leakage rate, unit: % / 24h; Pn is the absolute pressure at the n moment, unit: kPa; P n-i is the absolute pressure at the n-i moment, unit: kPa, i is the time coefficient, which converts the selected time period into unit time (per hour).

[0030] Step 3: Establish the pressure for the second time. According to the internal pressure of the reactor building, calculate the leakage rate per unit time. Based on the least squares method, construct a differential pressure - leakage rate relationship model, and calculate the leakage rate under the detection pressure; When the pressure in the reactor building rises to the detection pressure and remains static for a period of time, calculate the leakage rate during this period according to the ideal gas state equation. After maintaining the pressure for a period of time, multiple sets of leakage rate data are obtained. Based on the least squares method, construct a differential pressure - leakage rate relationship model to obtain the leakage rate result under the detection pressure.

[0031] For each time point ( t i ), the dry air mass ( W i ) in the containment is determined by the following formula according to the ideal gas law: In the formula: W i —Dry air mass in the containment; P i —Absolute pressure of the air in the containment corresponding to the i th group of data; P Vi —Weighted average partial pressure of water vapor in the containment corresponding to the i th group of data (indirectly calculated by measuring humidity); T i —Weighted average temperature of the air in the containment corresponding to the i th group of data; V —Volume of the free space in the containment; R —Dry air gas constant, 287.0 J / (kg K).

[0032] Due to the characteristics of the reactor type, the test conditions are very different from the traditional ones, and the environment within the test boundary is very complex. During the test, in order to maintain the operating environment temperature of the equipment within the test boundary (the reactor pit not exceeding 85°C) and considering the fire risk during the test, it is necessary to start the ventilation system to remove the heat within the test boundary. However, the existing ventilation system cannot be started during the test because it will damage the test boundary, and the containment isolation valve of the system needs to be closed. Therefore, it is necessary to design and add a ventilation cooling system for internal circulation within the containment. This system is started during the test to remove the heat within the test boundary to maintain the required environmental temperature.

[0033] During detection, it is not desirable to have the ventilation system operating, and the static pressure should be maintained. However, due to the above situation, the ventilation system must be started, so it is impossible to detect using traditional methods. The present invention adopts a mobile pressure filtering device, which can effectively eliminate the influence of dynamic pressure and measure a stable pressure.

[0034] As Figure 1 shown, a low-pressure rapid leakage detection device for the pressure boundary of a reactor building provided by the present invention is used to detect the leakage rate of the measured reactor building 101 under the detection pressure, and includes: an instantaneous leakage rate prediction unit, a leakage rate measurement unit, and a computer 102; the instantaneous leakage rate prediction unit and the leakage rate measurement unit are connected to the input interface of the computer 102 through a signal cable 10; the instantaneous leakage rate prediction unit measures the absolute pressure inside the reactor building and transmits the absolute pressure measurement data to the computer 102; the leakage rate measurement unit measures the internal pressure, differential pressure, environmental temperature, and relative humidity of the reactor building and transmits the measurement data of pressure, differential pressure, environmental temperature, and relative humidity to the computer 102; the computer 102 processes the absolute pressure measurement data and the measurement data of pressure, differential pressure, environmental temperature, and relative humidity, and calculates the instantaneous predicted leakage rate and the leakage rate under the detection pressure.

[0035] The instantaneous leakage rate prediction unit includes: a mobile pressure filtering device 1 and an absolute pressure gauge 2. The gas path of the absolute pressure gauge 2 is connected to the mobile pressure filtering device 1 through a pressure guiding hose 3, and the circuit is connected to the computer 102 through a signal cable 10. The mobile pressure filtering device 1 is used to filter the dynamic pressure to obtain a stable pressure; the absolute pressure gauge 2 measures the absolute pressure and transmits the absolute pressure measurement data to the computer 102, and the computer 102 processes the absolute pressure measurement data and calculates the instantaneous predicted leakage rate.

[0036] The absolute pressure gauge 2 adopted by the present invention is a high-precision absolute pressure gauge. In a specific embodiment, the range of the absolute pressure gauge 2 is: 80 - 120 kPa, and the accuracy is: 0.01% F.S.

[0037] The leakage rate measurement unit includes: a mobile pressure filtering device 1, a signal collector 5, a pressure gauge 6, a differential pressure gauge 7, a temperature sensor 8, and a humidity transmitter 9.

[0038] The gas path of the pressure gauge 6 is connected to the mobile pressure filtering device 1 through a pressure guiding hose 3, and the circuit is connected to the computer 102 through a signal cable 10; the mobile pressure filtering device 1 is used to filter the dynamic pressure to obtain a stable pressure for facilitating the calculation of the leakage rate; the pressure gauge 6 measures the pressure and transmits the pressure measurement data to the computer 102.

[0039] One end of the gas path of the differential pressure gauge 7 is connected to the mobile pressure filtering device 1 through a pressure guiding hose 3, and the other end communicates with the atmosphere; the circuit is connected to the computer 102 through a signal cable 10; the mobile pressure filtering device 1 is used to filter the dynamic pressure to obtain a stable pressure; the differential pressure gauge 7 measures the differential pressure data and transmits the differential pressure measurement data to the computer 102.

[0040] The temperature sensor 8 and the humidity transmitter 9 are respectively connected to the signal collector 5 through signal cables 10, and the signal collector 5 is connected to the computer 102 through a signal cable 10. The temperature sensor 8 measures the internal environmental temperature of the reactor building and transmits the environmental temperature measurement data to the computer 102 through the signal collector 5. The humidity transmitter 9 measures the relative humidity inside the reactor building and transmits the relative humidity measurement data to the computer 102 through the signal collector 5.

[0041] The computer 102 processes the measurement data of the pressure, differential pressure, environmental temperature, and relative humidity, uses the measured pressure, environmental temperature, and relative humidity data, calculates the leakage rate according to the ideal gas state equation, and performs linear fitting using the differential pressure - leakage rate relationship model based on the differential pressure and the calculated leakage rate to calculate the leakage rate under the specified pressure.

[0042] The mobile pressure filtering device 1 adopted in the present invention is arranged at a position inside the reactor building far from the wind disturbance. A three - way pressure measuring port 4 is provided inside the mobile pressure filtering device 1, and the gas paths of the absolute pressure gauge 2, the pressure gauge 6, and the differential pressure gauge 7 are respectively connected to the three - way pressure measuring port 4 through pressure guiding hoses 3.

[0043] The temperature sensor 8 and humidity transmitter 9 adopted in the present invention are arranged inside the reactor building. The free volume of the measured building is large, generally ranging from 50,000 to 150,000 cubic meters. According to the ideal gas state equation, it is necessary to obtain the weighted average temperature, humidity, and pressure inside the building during the test. In a large space, arranging only one sensor cannot effectively represent the true situation of this building. Therefore, the temperature and humidity fields are divided. Each sensor represents the temperature and humidity in that area, and the weighted sum is the average temperature and humidity of the entire building. In a specific embodiment, 50 temperature sensors 8 and 12 humidity transmitters 9 are arranged inside the reactor building. The 50 temperature sensors 8 and 12 humidity transmitters 9 are respectively connected in parallel to the signal acquisition instrument 5.

[0044] Embodiment Step 1: Preset the reference limit value of the leakage rate, set the signal sampling period, boost the pressure of the reactor building, and collect the internal physical parameters of the reactor building in real time and continuously. Preset the reference limit value of the leakage rate to 5% / 24h, set the signal sampling period to 1 min, boost the pressure of the reactor building, collect the internal physical parameters of the reactor building in real time and continuously, and proceed to Step 2.

[0045] In this embodiment, the internal physical parameters of the reactor building collected include: 2 absolute pressures, 50 ambient temperature parameters, 12 relative humidity parameters, and 1 differential pressure.

[0046] Step 2: Establish the pressure for the first time. According to the absolute pressure inside the reactor building, use the sliding window method to calculate the instantaneous predicted leakage rate, and compare the instantaneous predicted leakage rate with the preset leakage rate in real time. When the pressure of the reactor building rises to the detection pressure of 7700 Pa and stands still for 20 min, use the sliding window method to calculate the hourly pressure reduction rate, and calculate the instantaneous predicted leakage rate according to the pressure reduction rate. The calculation formula is: In the formula, L is the instantaneous predicted leakage rate, unit: % / 24h; P n is the n absolute pressure at time P n-i is the n-i absolute pressure at time i , unit: kPa,

[0047] In the prior art, according to the leakage characteristics of the reactor building, the conversion relationship between the common pressure reduction rate and the instantaneous predicted leakage rate can be obtained by looking up the table. The results are shown in Table 1: Table 1 Conversion Results of Pressure Reduction Rate and Instantaneous Predicted Leakage Rate Substitute the pressure reduction rate in Table 1 into the formula for calculating the instantaneous predicted leakage rate. The obtained instantaneous predicted leakage rate is very close to the actual leakage rate measured through multiple tests, that is, the pressure reduction rate is approximately equal to the instantaneous predicted leakage rate. Therefore, the pressure reduction rate (the relative change rate of pressure) is denoted as the value of the instantaneous predicted leakage rate.

[0048] This instantaneous predicted leakage rate is automatically updated every 3 seconds and compared with the preset leakage rate of 5% / 24h in real time: If the instantaneous predicted leakage rate is greater than the preset leakage rate value, the pressure boundary of the reactor building should be checked for leaks and defects eliminated until the instantaneous predicted leakage rate is lower than the preset leakage rate value. At this time, if the pressure in the reactor building is lower than the detection pressure, continue to supplement the pressure and transfer to Step 3.

[0049] Step 3: Establish the pressure for the second time. Calculate the leakage rate per unit time according to the internal pressure of the reactor building. Based on the least squares method, construct a differential pressure-leakage rate relationship model and calculate the leakage rate at the detection pressure; The pressure in the reactor building rises to the detection pressure of 7700 Pa and stands still for 20 minutes. According to the ideal gas state equation, calculate the leakage rate within a 30-minute period every 15 minutes. Keep the pressure for 4 hours to obtain 13 sets of leakage rates. Based on the least squares method, construct a differential pressure-leakage rate relationship model to obtain the leakage rate at a pressure of 7700 Pa.

[0050] Among them, the differential pressure-leakage rate relationship model is:[[]]END]] Since it is considered that under the assumption of the time length, the differential pressure has no significant change, and the leakage rate M and time t calculated by fitting the dry air mass within each data segment form a two-dimensional data set (M, t). During the seal test, several sets of (M, t) can be obtained. Perform linear regression on the dry air mass M and time t in these data sets respectively to obtain the fitting formula:[[]]END]] In the formula:[[]]END]] M mt : The leakage rate measured in the containment within the time, that is, the slope of the linear regression of the dry air mass M against time t; M 0 : The intercept of the linear regression of the dry air mass M against time t within the time.[[]]END]]

[0051] Every time length, the leakage rate M of the containment mt , differential pressure form another two-dimensional data set , perform regression on M mt for to obtain a fitting formula: In the formula: : different lower containment measured leakage rate.

[0052] The present invention has been described in detail above in conjunction with the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention. Contents not described in detail in the present invention can all adopt the prior art.

Claims

1. A method for rapid low-pressure leakage detection at the pressure boundary of a reactor building, characterized in that: The method comprises: Step 1: Preset the leakage rate benchmark limit, set the signal sampling period, pressurize the reactor building, and collect the internal physical parameters of the reactor building in real time and continuously; Step 2: Establish pressure for the first time, calculate the instantaneous predicted leakage rate using the sliding window method, and compare the instantaneous predicted leakage rate with the preset leakage rate in real time; Step 3: Establish the pressure for the second time, calculate the leakage rate per unit time, build a differential pressure-leakage rate relationship model based on the least squares method, and calculate the leakage rate under the specified pressure.

2. A method for rapid low-pressure leakage detection at the pressure boundary of a reactor building according to claim 1, characterized in that: The physical parameters inside the reactor building collected in step 1 include: absolute pressure, ambient temperature, relative humidity, and differential pressure.

3. A method for rapid low-pressure leakage detection at the pressure boundary of a reactor building according to claim 1, characterized in that: The formula for calculating the instantaneous predicted leakage rate in step 2 is: In the formula, L It is the instantaneous predicted leakage rate, unit: % / 24h; P n For the n Absolute pressure at the moment, unit: kPa; P n-i For the n- i Absolute pressure at the moment, unit: kPa, i is the time coefficient, which converts the selected time period into unit time.

4. A method for rapid low-pressure leakage detection at the pressure boundary of a reactor building according to claim 1, characterized in that: The real-time comparison of the instantaneous predicted leakage rate with the preset leakage rate in step 2 includes: if the instantaneous predicted leakage rate is greater than the preset leakage rate value, the pressure boundary of the reactor building should be checked for leaks and eliminated until the instantaneous predicted leakage rate is lower than the preset leakage rate value.

5. A method for rapid low-pressure leakage detection at the pressure boundary of a reactor building according to claim 1, characterized in that: After the pressure is first established in step 2, the reactor building pressure is increased to reach the detection pressure. If the reactor building pressure is lower than the detection pressure, the pressure is further increased.

6. A reactor building pressure boundary low pressure rapid leakage detection device, characterized in that: The device comprises: a leakage rate instantaneous prediction unit, a leakage rate measurement unit, and a computer (102); the leakage rate instantaneous prediction unit and the leakage rate measurement unit are connected to an input interface of the computer (102); the leakage rate instantaneous prediction unit measures the absolute pressure inside the reactor building, and transmits the absolute pressure measurement data to the computer (102); the leakage rate measurement unit measures the pressure, differential pressure, ambient temperature, and relative humidity inside the reactor building, and transmits the pressure, differential pressure, ambient temperature, and relative humidity measurement data to the computer (102); the computer (102) processes the absolute pressure measurement data and the pressure, differential pressure, ambient temperature, and relative humidity measurement data, and calculates the instantaneous prediction leakage rate and the leakage rate under the detection pressure.

7. A reactor building pressure boundary low pressure rapid leakage detection device according to claim 6, characterized in that: The instantaneous leakage rate prediction unit comprises: a mobile pressure filter device (1) and an absolute pressure gauge (2); the mobile pressure filter device (1) is arranged at a location inside a reactor building away from wind disturbances; the absolute pressure gauge (2) is connected to the mobile pressure filter device (1) via a gas line, and connected to a computer (102) via a circuit; the mobile pressure filter device (1) is used to filter dynamic pressure to obtain a stable pressure; the absolute pressure gauge (2) measures absolute pressure and transmits absolute pressure measurement data to the computer (102); the computer (102) processes the absolute pressure measurement data to calculate and obtain an instantaneous predicted leakage rate.

8. A reactor building pressure boundary low-pressure rapid leakage detection device according to claim 7, characterized in that: The absolute pressure gauge (2) is a high-precision absolute pressure gauge with a measuring range of 80-120 kPa and an accuracy of 0.01% FS.

9. A reactor building pressure boundary low-pressure rapid leakage detection device according to claim 6, characterized in that: The leakage rate measurement unit comprises: a mobile pressure filter device (1), a signal acquisition instrument (5), a pressure gauge (6), a differential pressure gauge (7), a temperature sensor (8), and a humidity transmitter (9); The mobile pressure filter device (1) is arranged at a location inside the reactor building away from wind disturbances, and the temperature sensor (8) and the humidity transmitter (9) are arranged inside the reactor building; The pressure gauge (6) is connected to the mobile pressure filter device (1) through an air circuit, and is connected to the computer (102) through an electric circuit; the mobile pressure filter device (1) is used to filter the dynamic pressure to obtain a stable pressure; the pressure gauge (6) measures the pressure and transmits the pressure measurement data to the computer (102); One end of the differential pressure gauge (7) is connected to the mobile pressure filter device (1) through an air circuit, and the other end is connected to the atmosphere; the circuit is connected to the computer (102); the differential pressure gauge (7) measures differential pressure data and transmits the differential pressure measurement data to the computer (102); The temperature sensor (8) and the humidity transmitter (9) are respectively connected to the signal acquisition instrument (5), and the signal acquisition instrument (5) is connected to the computer (102); the temperature sensor (8) measures the internal ambient temperature of the reactor building, and transmits the ambient temperature measurement data to the computer (102) via the signal acquisition instrument (5); the humidity transmitter (9) measures the internal relative humidity of the reactor building, and transmits the relative humidity measurement data to the computer (102) via the signal acquisition instrument (5); The computer (102) processes the pressure, differential pressure, ambient temperature, and relative humidity measurement data, and uses the measured pressure, ambient temperature, and relative humidity data to calculate the leakage rate according to the ideal gas state equation; and uses the differential pressure-leakage rate relationship model to perform linear fitting based on the differential pressure and the calculated leakage rate to calculate the leakage rate under the specified pressure.

10. A reactor building pressure boundary low-pressure rapid leakage detection device according to any one of claims 7 or 9, characterized in that: The mobile pressure filter device (1) is provided with a three-way pressure measuring port (4) inside, and the gas paths of the absolute pressure gauge (2), the pressure gauge (6), and the differential pressure gauge (7) are respectively connected to the three-way pressure measuring port (4) via a pressure-leading hose (3).

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