A method for measuring leakage rate of nuclear power plant containment integral test

Abstract

The present invention specifically relates to a nuclear power plant containment overall test leakage rate measurement algorithm, comprising a leakage rate function construction module, a full-time period data acquisition module, and a measurement value validity calculation module. The full-time period data acquisition module is used to obtain full-time period leakage rate measurements and send them to the measurement value validity calculation module. The leakage rate function construction module is used to obtain a ratio-based leakage rate function and send it to the measurement value validity calculation module. The measurement value validity calculation module is used to receive the ratio-based leakage rate function sent by the leakage rate function construction module and the full-time period leakage rate measurements sent by the full-time period data acquisition module, calculate the confidence limit, and compare it with the limit. The nuclear power plant containment overall test leakage rate measurement algorithm of the present invention shortens the nuclear power plant containment overall test leakage rate measurement time.

Description

Technical Field

[0001] The present invention relates to the technical field of performance testing, in particular to a method for measuring leakage rate of an integral test of a containment vessel of a nuclear power plant. Background Art

[0002] The containment leak rate measurement test is one of the key safety-related tests during the commissioning and commercial operation of a nuclear power plant. For example, for pressurized water reactors (PWRs), the test is conducted every 10 years after commissioning. Dry air is used to pressurize the containment to its design pressure at a constant rate, simulating the pressure within the containment under design basis accident conditions. This test verifies that the containment, the third line of nuclear safety, and its associated components meet the sealing and structural requirements. While the test is underway, other overhaul work within the nuclear island is suspended, occupying the nuclear island's critical path for nearly 100 hours. This significantly impacts the overhaul schedule, as it is characterized by high risk, complex organization, and a long occupancy of the critical path.

[0003] In recent years, with the continuous commissioning of domestic nuclear power units, the frequency of this test has increased significantly. How to optimize the measurement method of the leakage rate of the overall containment test to achieve a suitable "balance point" between nuclear safety, quality, construction period and efficiency has become a major issue that must be solved by current nuclear power performance test practitioners.

[0004] Currently, domestic containment leak rate measurement methods rely on real-time monitoring and measurement using absolute and mass point methods, with large amounts of collected measurement data processed and analyzed in real time. The validity of the final measurement results is determined using different evaluation methods depending on the reactor type, test plant, and unit. This results in longer leak rate measurement times for containment leak rate tests compared to some units abroad. Summary of the Invention

[0005] Based on this, it is necessary to provide a nuclear power plant containment overall test leakage rate measurement method to address the problem of long measurement time of the existing containment overall test leakage rate, which shortens the measurement time of the nuclear power plant containment overall test leakage rate.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for measuring leakage rate of an integral containment test of a nuclear power plant, comprising a leakage rate function construction module, a full-time period data acquisition module, and a measurement value validity calculation module;

[0008] The full-time period data acquisition module is used to obtain the leakage rate measurement value of the full-time period and send it to the measurement value validity calculation module;

[0009] The leakage rate function construction module is used to obtain the leakage rate function in the form of a ratio and send it to the measurement value validity calculation module;

[0010] The measurement value validity calculation module is used to receive the ratio form leakage rate function sent by the leakage rate function construction module and the full time period leakage rate measurement value sent by the full time period data acquisition module, solve the confidence upper limit and compare it with the limit value.

[0011] Furthermore, the leakage rate function construction module obtains the leakage rate function in ratio form, including the following steps:

[0012] The leakage rate measurement value L for the entire time period is equivalent to the ratio of the normal variable y to the normal variable x, and is constructed into a standard statistical variable form:

[0013] L=y / x.

[0014] Furthermore, the measurement value validity calculation module solves the confidence upper limit of the leakage rate measurement value for the entire time period, including the following steps:

[0015] (1) Assuming that the residual of the leakage rate measurement value of the entire time period is a normal variable, the periodic disturbance data is eliminated when evaluating the validity of the leakage rate measurement value of the entire time period;

[0016] (2) Since the residual of the leakage rate measurement value in the whole time period is independent of the calculation time length when the normal distribution is satisfied, the confidence upper limit of the leakage rate measurement value in the whole time period is solved by using the hypothesis testing principle in statistical distribution;

[0017] (3) If the confidence intervals before and after shortening the leakage rate measurement time of the nuclear power plant containment overall test are within an acceptable range, shortening the measurement time is feasible.

[0018] Furthermore, assuming that the residual of the leakage rate measurement value of the entire time period is a normal variable d, the periodic disturbance data is eliminated when evaluating the validity of the leakage rate measurement value of the entire time period:

[0019] d=y-UCLx

[0020] Where UCL is the upper confidence limit of the leakage rate measurement value for the entire time period.

[0021] Furthermore, the hypothesis testing principle in statistical distribution is used to solve the confidence upper limit of the leakage rate measurement value for the entire time period, including the following steps:

[0022] The variance of the normal variable d is:

[0023] S d 2 =S y 2 -2UCLCov(xy)+UCL 2 S x 2

[0024] Where s d 2 is the variance of the normal variable d, S y 2 is the variance of the normal variable y, S x 2 is the variance of the normal variable x, Cov(xy) is the covariance of the normal variable y and the normal variable x;

[0025] Construct the statistical distribution function of the normal variable d based on the Fieller criterion, Delta function or Bootstrap method, taking the standard Student distribution as an example:

[0026] (t 2 S x 2 )UCL 2 -(2t 2 Cov(xy)UCL+t 2 S y 2 =x 2 UCL 2 -(2xy)UCL+y 2

[0027] By solving the problem, the confidence upper limit of the leakage rate measurement value for the entire time period is:

[0028]

[0029] Furthermore, the full-time period data acquisition module acquires the leakage rate measurement value of the full-time period, including the following steps:

[0030] (1) Taking any time point as the independent variable and the leakage rate estimate as the dependent variable, obtain one-dimensional time series leakage rate data;

[0031] (2) Taking any time period including the start and end points as the independent variable and the leakage rate estimate as the dependent variable, the one-dimensional time series leakage rate data in step 1 is expanded into two-dimensional time series leakage rate data, thereby obtaining the leakage rate measurement value of the entire time period.

[0032] Furthermore, the leakage rate estimated value is obtained by a leakage rate estimation method, which is a mass point-time method, a process parameter-time method or an arbitrary two time point method.

[0033] Furthermore, the leakage rate estimate L is obtained by the mass point-time method, which includes the following steps:

[0034] (1) By linearly fitting the function M(t) of the dry air mass M in the containment relative to time t, the linear fitting slope A and the linear fitting intercept B are obtained:

[0035] M(t)=At+B

[0036] (2) Calculate the estimated leakage rate L using the following formula:

[0037] L=M(t)

[0038]

[0039] Where L is the estimated leakage rate; M is the mass of dry air in the containment of the nuclear power plant; and t is time.

[0040] Furthermore, the process parameter-time method calculates the leakage rate estimate L using the following formula:

[0041]

[0042] Where S V is the rate of change of the volume of dry air in the containment over time, S P is the rate of change of the average absolute pressure of dry air in the containment over time, S H is the rate of change of the average steam partial pressure in the containment over time, S T is the rate of change of the average absolute temperature of the dry air in the containment with time;

[0043] V is the volume of dry air in the containment, P is the average absolute pressure of dry air in the containment, H is the average steam partial pressure in the containment, and T is the average absolute temperature of dry air in the containment;

[0044] V0 is the volume of dry air in the containment at the time of initial measurement, P0 is the average absolute pressure of dry air in the containment at the time of initial measurement, H0 is the average steam content in the containment at the time of initial measurement, and T0 is the average absolute temperature of dry air in the containment at the time of initial measurement.

[0045] Furthermore, the leakage rate estimate L is obtained by the arbitrary two time point method using the following formula:

[0046]

[0047] Where M1 is the mass of dry air in the containment at time t1, M2 is the mass of dry air in the containment at time t2, and t1 and t2 are any two points in the measurement process.

[0048] Furthermore, the one-dimensional time series leakage rate data is the following function with any time point as the independent variable and the leakage rate estimate as the dependent variable: L = f(t); the two-dimensional time series leakage rate data is the function with any time period including the start point and the end point as the independent variable and the leakage rate estimate as the dependent variable: L = f(t1, t2). The one-dimensional time series leakage rate data and the two-dimensional time series leakage rate data are converted into each other. The method for obtaining the one-dimensional time series leakage rate data is equivalent to obtaining a certain set of data after fixing the calculation starting point of the two-dimensional time series leakage rate data.

[0049] Beneficial technical effects of the present invention:

[0050] The present invention's nuclear power plant containment leak rate measurement method combines data analysis, leak rate calculation, and result validity assessment. It thoroughly analyzes measurement data and uses multiple methods to evaluate leak rates across all feasible calculation time periods. Without changing existing standards and test procedures, this calculation method effectively shortens leak rate measurement time for containment tests, helping to achieve a balance between nuclear safety, quality, timelines, and efficiency in containment leak rate measurement.

[0051] The nuclear power plant containment overall test leakage rate measurement method of the present invention expands the existing one-dimensional time series leakage rate data to two dimensions. Without changing the existing hardware configuration, the method increases the leakage rate calculation value of the measurement platform, allowing for a more intuitive and accurate assessment of the containment sealing performance. This improves the validity of the measurement results without violating regulatory standards.

[0052] The nuclear power plant containment overall test leakage rate measurement method of the present invention can evaluate the relationship between the measurement time and the effectiveness of the measurement results based on the termination criteria required by standards and regulations. Within the allowable range, the optimized measurement time can be determined. The optimized measurement time is significantly shorter than the existing measurement time based on historical data and engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a schematic flow chart of a method for measuring leakage rate during an overall test of a nuclear power plant containment vessel according to the present invention;

[0054] Figure 2 This is a schematic structural diagram of a method for measuring leakage rate during an overall test of a nuclear power plant containment vessel according to the present invention;

[0055] Figure 3 This is a comparison diagram of the effect of the nuclear power plant containment overall test leakage rate measurement method in Example 1;

[0056] Figure 4 This is a schematic diagram of one-dimensional time series leakage rate data of Example 1;

[0057] Figure 5Schematic diagram of leakage rate measurement values over the entire time period of Example 1. DETAILED DESCRIPTION

[0058] See also Figure 2 The present invention provides a method for measuring the leakage rate of a nuclear power plant containment overall test, which includes a leakage rate function construction module, a full-time period data acquisition module and a measurement value validity calculation module.

[0059] The full-time period data acquisition module is used to obtain the leakage rate measurement value of the full-time period and send it to the measurement value validity calculation module.

[0060] The full-time period data acquisition module acquires the leakage rate measurement value of the full-time period, including the following steps:

[0061] 1. Take any time point as the independent variable and the leakage rate estimate as the dependent variable to obtain one-dimensional time series leakage rate data;

[0062] 2. Using any time period including the start and end points as the independent variable and the leakage rate estimate as the dependent variable, expand the one-dimensional time series leakage rate data in step 1 into two-dimensional time series leakage rate data to obtain leakage rate measurements for the entire time period.

[0063] The nuclear power plant containment overall test leakage rate measurement method of the present invention is applicable to all one-dimensional time series leakage rate data, and is applicable to a variety of leakage rate estimation methods based on the absolute pressure inside the shell, the steam partial pressure inside the shell or the temperature inside the shell, and meets the ideal gas equation principle adopted in the containment overall test leakage rate measurement test.

[0064] The nuclear power plant containment overall test leakage rate measurement method of the present invention assumes that the dry air in the containment conforms to the basic principle of ideal gas:

[0065] (PH)V=MRT

[0066] Where P is the average absolute pressure of dry air in the containment, in MPa; H is the average steam partial pressure in the containment, in MPa; V is the volume of dry air in the containment, in m 3 ; M is the mass of dry air in the containment, in kg; R is the product of the universal gas constant and the molar mass of dry air, in J / mol.k; T is the average absolute temperature of dry air in the containment, in K.

[0067] The leakage rate estimated value is obtained by a leakage rate estimation method, which includes a mass point-time method, a process parameter-time method, or an arbitrary two time point method.

[0068] The leak rate estimate L is obtained using the mass point-time method, which includes the following steps:

[0069] (1) By linearly fitting the function M(t) of the dry air mass M in the containment relative to time t, the linear fitting slope A and the linear fitting intercept B are obtained:

[0070] M(t)=At+B

[0071] (2) Calculate the estimated leakage rate L using the following formula:

[0072] L=M(t)

[0073]

[0074] Where L is the estimated leakage rate in kg / h; M is the mass of dry air in the containment of the nuclear power plant in kg; and t is the time in h.

[0075] The process parameter-time method uses the following formula to calculate the estimated leakage rate L:

[0076]

[0077] Where S V is the rate of change of the volume of dry air in the containment over time, in m 3 / h;S P is the rate of change of the average absolute pressure of dry air in the containment over time, in MPa / h; S H is the rate of change of the average steam partial pressure in the containment over time, in MPa / h; S T is the rate of change of the average absolute temperature of the dry air in the containment with time, in k / h; V is the volume of the dry air in the containment, in m 3 ; P is the average absolute pressure of dry air in the containment, in MPa; H is the average steam partial pressure in the containment, in MPa; T is the average absolute temperature of dry air in the containment, in K; V0 is the volume of dry air in the containment at the time of initial measurement, in m 3 ; P0 is the average absolute pressure of dry air in the containment at the initial measurement, in MPa; H0 is the average steam partial pressure in the containment at the initial measurement, in MPa; T0 is the average absolute temperature of dry air in the containment at the initial measurement, in K.

[0078] The leakage rate estimate L is obtained by the following formula using the arbitrary two time points method:

[0079]

[0080] Where M1 is the mass of dry air in the containment at time t1, in kg; M2 is the mass of dry air in the containment at time t2, and t1 and t2 are any two points in the measurement process, in h.

[0081] One-dimensional time-series leakage rate data is a function of any time point as the independent variable and the estimated leakage rate as the dependent variable: L = f(t). Two-dimensional time-series leakage rate data is a function of any time period, including a start and end point, as the independent variable and the estimated leakage rate as the dependent variable: L = f(t1, t2). One-dimensional and two-dimensional time-series leakage rate data can be converted into each other. The method for acquiring one-dimensional time-series leakage rate data is equivalent to acquiring a set of data from two-dimensional time-series leakage rate data with a fixed starting time. For example, if a two-dimensional time-series leakage rate data with an arbitrary starting time t1 and a time length t2 has t1 × t2 data points, then a certain-dimensional time-series leakage rate data with a selected fixed starting time and a time length t2 has 1 × t2 data points.

[0082] Therefore, one of the features of the present invention is that it obtains more possible results without violating existing test methods, and can realize the calculation of leakage rate values after shortening the platform time, where the platform time is the time during which the overall test of the containment shell lasts at the containment shell design pressure, which is equal to the sum of t1+t2 in the two-dimensional time series.

[0083] The leakage rate function construction module is used to obtain the leakage rate function in the form of a ratio and send it to the measurement value validity calculation module.

[0084] See also Figure 1 The leakage rate function construction module obtains the leakage rate function in the form of a ratio, including the following steps: the leakage rate measurement value L of the entire time period is equivalent to the ratio of the normal variable y to the normal variable x, and is constructed into a standard statistical variable form:

[0085] L=y / x.

[0086] The measurement value validity calculation module is used to receive the ratio form leakage rate function sent by the leakage rate function construction module and the full time period leakage rate measurement value sent by the full time period data acquisition module, solve the full time period leakage rate measurement value confidence limit and compare it with the limit value.

[0087] The measurement value validity calculation module solves the confidence upper limit of the leakage rate measurement value of the entire time period, including the following steps:

[0088] 1. Assuming that the residual of the leakage rate measurement value for the entire time period is a normal variable d, when evaluating the validity of the leakage rate measurement value for the entire time period, eliminate periodic disturbance data such as instrument errors:

[0089] d=y-UCLx

[0090] Where, UCL is the confidence upper limit of the leakage rate measurement value for the entire time period;

[0091] 2. Since the residual of the leakage rate measurement value for the entire time period is independent of the calculation time length when the normal distribution is satisfied, the hypothesis testing principle in statistical distribution can be used to solve the confidence upper limit of the leakage rate measurement value for the entire time period. The specific implementation method is as follows:

[0092] The variance of the normal variable d is:

[0093] S d 2 =S y 2 -2UCLCov(xy)+UCL 2 S x 2

[0094] Where S d 2 is the variance of the normal variable d, S y 2 is the variance of the normal variable y, S x 2 is the variance of the normal variable x, Cov(xy) is the covariance of the normal variable y and the normal variable x;

[0095] Construct the statistical distribution function of the normal variable d based on the Fieller criterion, Delta function or Bootstrap method, taking the standard Student distribution as an example:

[0096] (t 2 S x 2 )UCL 2 -(2t 2 Cov(xy))UCL+t 2 S y 2 =x 2 UCL 2 -(2xy)UCL+y 2

[0097] By solving the problem, the confidence upper limit of the leakage rate measurement value for the entire time period is:

[0098]

[0099] 3. If the confidence intervals before and after shortening the leakage rate measurement time of the nuclear power plant containment overall test are within an acceptable range, shortening the measurement time is feasible.

[0100] The nuclear power plant containment overall test leakage rate measurement method of the present invention evaluates the leakage rate measurement values of the entire time period from multiple directions and angles, and can simultaneously adopt multiple confidence interval calculation and evaluation methods including but not limited to the Fieller criterion, Delta function and Bootstrap method, covering multiple evaluation fields such as similar unit comprehensive evaluation, historical data analysis, linear error and nonlinear error calculation. The full-time period data acquisition method can be used in each evaluation field, which greatly expands the depth and breadth of existing evaluation methods and can provide a scientific basis and guidance for the evaluation and review of containment sealing performance.

[0101] The nuclear power plant containment overall test leakage rate measurement method of the present invention can replace or supplement the existing leakage rate measurement value evaluation process. If it is based on the Fieller criterion, it can be converted into the form in the standard regulations through mathematical identity transformation. It is an extension and supplement to the existing theoretical system and is conducive to the comprehensive evaluation of the overall sealing performance of the containment.

[0102] The present invention provides a method for measuring the leakage rate of an integral containment test for a nuclear power plant, including a method for calculating the leakage rate at any two time points based on the absolute pressure inside the containment, the partial pressure of steam inside the containment, or the temperature inside the containment; a method for acquiring data for a full time period with any calculation starting point and any calculation time length as independent variables; and a method for evaluating the effectiveness of leakage rate measurements by constructing a relationship between the leakage rate residual and a distribution function. This method theoretically demonstrates that shortening the leakage rate measurement time for an integral containment test for a nuclear power plant is reasonable and feasible. Specifically:

[0103] (1) The data acquisition method of expanding one-dimensional time series data to two-dimensional data greatly expands the amount of data for calculation and analysis, making it more intuitive and accurate. By selecting a reasonable time period, if the time period for the final calculation of the leakage rate is within the shortened time platform, the time can be shortened.

[0104] (2) A new leakage rate evaluation process system was constructed. While maintaining consistency with the regulatory standards based on engineering practice, it greatly expanded the breadth and depth of the evaluation process, allowing for comprehensive evaluation using a variety of scientific methods, and providing important basis and guidance for supervising the overall sealing performance status of the containment.

[0105] (3) For the first time, a functional relationship between any measurement time period and the measurement results was established, which can directly evaluate the impact of the measurement time period on the leakage results. Based on the set reasonable limits, the most reasonable and feasible measurement platform can be selected, which is of great significance to shortening the measurement time of the leakage rate of the overall test of the nuclear power plant containment.

[0106] The nuclear power plant containment overall test leakage rate measurement method of the present invention is based on mature and widely used statistical principles, and has been verified by a large number of different reactor types and units. It has extremely high scientific rigor and versatility and has sufficient promotion value.

[0107] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0108] Example 1

[0109] See also Figure 3 The nuclear power plant containment overall test leakage rate measurement method of the present invention is applied to a nuclear power plant containment leakage rate calculation method based on the absolute pressure inside the shell at any two time points, and the leakage rate measurement time is shortened from the original 24 hours to 16 hours.

[0110] See also Figure 4 Before the implementation of the nuclear power plant containment overall test leakage rate measurement method of the present invention, as the test time increases, the leakage rate measurement data increases, which is a one-dimensional time series data, with the test time as the horizontal axis and the leakage rate measurement value as the vertical axis.

[0111] See also Figure 5 After the nuclear power plant containment overall test leakage rate measurement method of the present invention is implemented, after obtaining the leakage rate of the entire time period, the leakage rate is represented by different color depths with the time starting point t1 as the horizontal axis and the time length t2 as the vertical axis.

[0112] Through richer and more comprehensive two-dimensional time series data, the leakage rate data of all containment overall tests at different time points and time periods can be intuitively obtained, and the containment sealing performance can be evaluated in real time. After meeting the limit and accuracy requirements of the platform leakage rate measurement, the platform end time can be quickly evaluated in the shortest time. That is, the platform time after optimization using this calculation method can be further shortened compared with before optimization.

[0113] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for measuring the leakage rate of a nuclear power plant containment vessel overall test, characterized in that: It includes a leakage rate function building module, a full-time period data acquisition module and a measurement value validity calculation module; The full-time period data acquisition module is used to obtain the leakage rate measurement value of the full-time period and send it to the measurement value validity calculation module; The leakage rate function construction module is used to obtain the leakage rate function in the form of a ratio and send it to the measurement value validity calculation module; The measurement value validity calculation module is used to receive the ratio form leakage rate function sent by the leakage rate function construction module and the full time period leakage rate measurement value sent by the full time period data acquisition module, solve the confidence upper limit and compare it with the limit value; The measurement value validity calculation module solves the confidence upper limit of the leakage rate measurement value of the entire time period, including the following steps: (1) Assuming that the residual of the leakage rate measurement value of the entire time period is a normal variable, the periodic disturbance data is eliminated when evaluating the validity of the leakage rate measurement value of the entire time period; (2) Since the residual of the leakage rate measurement value in the whole time period is independent of the calculation time length when the normal distribution is satisfied, the confidence upper limit of the leakage rate measurement value in the whole time period is solved by using the hypothesis testing principle in statistical distribution; (3) If the confidence intervals before and after shortening the leakage rate measurement time of the nuclear power plant containment overall test are within an acceptable range, shortening the measurement time is feasible; The full-time period data acquisition module acquires the leakage rate measurement value of the full-time period, including the following steps: (1) Taking any time point as the independent variable and the leakage rate estimate as the dependent variable, obtain one-dimensional time series leakage rate data; (2) Taking any time period including the start and end points as the independent variable and the leakage rate estimate as the dependent variable, the one-dimensional time series leakage rate data in step 1 is expanded into two-dimensional time series leakage rate data, thereby obtaining the leakage rate measurement value of the entire time period.

2. The method for measuring leakage rate of the nuclear power plant containment vessel integral test according to claim 1, characterized in that: The leakage rate function construction module obtains the leakage rate function in the form of a ratio, including the following steps: The leakage rate measurement value L for the entire time period is equivalent to the ratio of the normal variable y to the normal variable x, and is constructed into a standard statistical variable form: L=y / x.

3. The method for measuring leakage rate of the nuclear power plant containment vessel integral test according to claim 1, characterized in that: In step (1), it is assumed that the residual of the leakage rate measurement value of the entire time period is a normal variable d. When evaluating the validity of the leakage rate measurement value of the entire time period, the periodic disturbance data is eliminated: d=y-UCLx Where, UCL is the confidence upper limit of the leakage rate measurement value for the entire time period; In step (2), the hypothesis testing principle in statistical distribution is used to solve the confidence upper limit of the leakage rate measurement value for the entire time period, including the following steps: The variance of the normal variable d is: S d 2 =S y 2 -2UCLCov(xy)+UCL 2 S x 2 Where S d 2 is the variance of the normal variable d, S y 2 is the variance of the normal variable y, S x 2 is the variance of the normal variable x, Cov(xy) is the covariance of the normal variable y and the normal variable x; The statistical distribution function of the normal variable d is constructed based on the Fieller criterion, Delta function or Bootstrap method to obtain the upper confidence limit of the leakage rate measurement value in the entire time period.

4. The method for measuring leakage rate of a nuclear power plant containment vessel as claimed in claim 1, wherein: The leakage rate estimated value is obtained by a leakage rate estimation method, which is a mass point-time method, a process parameter-time method, or an arbitrary two time point method.

5. The method for measuring leakage rate of the nuclear power plant containment vessel integral test according to claim 4, characterized in that: Leak rate estimates obtained using the mass-time method , including the following steps: (1) By linearly fitting the function M(t) of the dry air mass M in the containment relative to time t, the linear fitting slope A and the linear fitting intercept B are obtained: M(t)=At+B (2) Calculate the estimated leakage rate using the following formula : Where, is the estimated leakage rate; M is the mass of dry air in the containment of the nuclear power plant; t is the time.

6. The method for measuring leakage rate of the nuclear power plant containment vessel integral test according to claim 4, characterized in that: The process parameter-time method uses the following formula to calculate the leakage rate estimate : Where S V is the rate of change of the volume of dry air in the containment over time, S P is the rate of change of the average absolute pressure of dry air in the containment over time, S H is the rate of change of the average steam partial pressure in the containment over time, S T is the rate of change of the average absolute temperature of the dry air in the containment with time; V is the volume of dry air in the containment, P is the average absolute pressure of dry air in the containment, H is the average steam partial pressure in the containment, and T is the average absolute temperature of dry air in the containment; V0 is the volume of dry air in the containment at the time of initial measurement, P0 is the average absolute pressure of dry air in the containment at the time of initial measurement, H0 is the average steam content in the containment at the time of initial measurement, and T0 is the average absolute temperature of dry air in the containment at the time of initial measurement.

7. The method for measuring leakage rate of the nuclear power plant containment vessel integral test according to claim 4, characterized in that: The leakage rate estimate is obtained by the following formula using the method of any two time points : Where M1 is the mass of dry air in the containment at time t1, M2 is the mass of dry air in the containment at time t2, and t1 and t2 are any two points in the measurement process.

8. The method for measuring leakage rate of a nuclear power plant containment vessel integral test according to any one of claims 1 to 7, characterized in that: One-dimensional time series leak rate data is the following function with any time point as the independent variable and the leak rate estimate as the dependent variable: The two-dimensional time series leakage rate data is a function with any time period including the start and end points as the independent variable and the leakage rate estimate as the dependent variable: One-dimensional time series leakage rate data and two-dimensional time series leakage rate data are converted to each other. The method for obtaining one-dimensional time series leakage rate data is equivalent to obtaining a certain set of data after fixing the calculation starting point of two-dimensional time series leakage rate data.

Images