Method and system for calculating leakage rate of primary loop of nuclear power plant

Abstract

The invention provides a nuclear power plant primary loop leakage rate calculation method and system, and the method comprises the steps: controlling a cooling medium to circularly flow in a test pipeline under a first preset pressure, and detecting whether the pressure boundary of a primary loop leaks or not; when the pressure boundary of the primary loop does not leak, controlling the circulating flow test duration of the cooling medium in the test pipeline under a second preset pressure, detecting whether recognizable leakage exists in the primary loop, and obtaining a recognizable leakage rate, a side leakage rate outside the pressure boundary of the primary loop and test data; calculating the overall leakage rate of the loop according to the test data and the test duration; and calculating the total leakage rate and the unidentifiable leakage of the loop according to the overall leakage rate, the identifiable leakage rate and the side leakage rate. According to the invention, when the auxiliary system of the unit under construction of the nuclear power plant is not completed, a set of test water tank can be connected between the discharge pipeline interface and the charge pipeline interface of the loop.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plants, and in particular to a method and system for calculating the leakage rate of the primary loop in a nuclear power plant. Background Technology

[0002] The reactor coolant system in a nuclear power plant is a critical system for transferring heat generated by the reactor to heat exchange equipment. The primary loop leakage rate measurement test is an important component of the primary loop hydrostatic test, and the results determine whether acceptance criteria are met. Currently, the primary loop hydrostatic test in nuclear power plants requires both the primary loop and its auxiliary systems to be in a usable state. However, for nuclear power units under construction, the primary loop hydrostatic test cannot be performed because the auxiliary systems are not yet fully usable, hindering project progress. Therefore, improvements are needed. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method and system for calculating the primary loop leakage rate of a nuclear power plant, in order to solve the problem that the primary loop cannot be tested for nuclear power units under construction in the prior art.

[0004] To achieve the above and other related objectives, the present invention provides a method for calculating the leakage rate of the primary loop of a nuclear power plant, wherein a test water tank is connected between the lower leakage pipeline interface and the upper filling pipeline interface of the primary loop to form a test pipeline;

[0005] The method comprises:

[0006] The cooling medium is controlled to circulate in the test pipeline at a first preset pressure to detect whether there is leakage at the primary loop pressure boundary.

[0007] When no leakage occurs at the pressure boundary of the primary loop, the cooling medium is controlled to circulate in the test pipeline for a test duration at a second preset pressure to detect whether there is an identifiable leakage in the primary loop, and to obtain the identifiable leakage rate, the side leakage rate outside the pressure boundary of the primary loop, and test data; wherein, the first preset pressure is less than the second preset pressure, and the second preset pressure is the set acceptance pressure;

[0008] Based on the test data and test duration, calculate the overall leakage rate of the primary loop;

[0009] The total leakage rate and the unidentifiable leakage rate of the primary loop are calculated based on the overall leakage rate, the identifiable leakage rate, and the side leakage rate.

[0010] The test results for the first loop are generated based on the total leakage rate and the unidentifiable leakage rate.

[0011] In one embodiment of the present invention, the step of detecting whether there is an identifiable leakage in the first loop and obtaining the identifiable leakage rate includes:

[0012] Detect whether there is an identifiable leak in the primary loop:

[0013] When an identifiable leak exists in the first loop, the identifiable leak rate is obtained through detection.

[0014] When there is no identifiable leakage in the loop, the identifiable leakage rate is 0.

[0015] In one embodiment of the present invention, the step of obtaining the identifiable leakage rate by detection when an identifiable leakage exists in the first loop includes:

[0016] When there is an identifiable leak in the primary circuit, and the main pump of the primary circuit is not equipped with a shaft seal riser, the leakage rate at the pressure boundary of the primary circuit and the side leakage rate outside the pressure boundary of the primary circuit are detected.

[0017] The identifiable leakage rate of the first loop is calculated based on the leakage rate at the pressure boundary of the first loop and the side leakage rate outside the pressure boundary of the first loop.

[0018] In one embodiment of the present invention, the step of obtaining the identifiable leakage rate by detection when an identifiable leakage exists in the first loop includes:

[0019] When there is an identifiable leak in the primary circuit and the main pump of the primary circuit is equipped with a shaft seal riser, the leakage rate at the pressure boundary of the primary circuit, the side leakage rate outside the pressure boundary of the primary circuit, and the injection rate of the main pump shaft seal riser are detected.

[0020] The identifiable leakage rate of the first circuit is calculated based on the leakage rate at the pressure boundary of the first circuit, the side leakage rate outside the pressure boundary of the first circuit, and the injection rate of the main pump shaft seal riser.

[0021] In one embodiment of the invention, the identifiable leakage rate Q of the primary loop is... D0 ,satisfy:

[0022] Q D0 =Q D1 +Q D2 -Q D3 ;

[0023] Among them, Q D1 The leakage rate, Q, is expressed as the pressure boundary leakage rate of the primary loop. D2 Q is the side leakage rate outside the primary loop pressure boundary. D3 This is expressed as the injection rate of the main pump shaft seal riser.

[0024] In one embodiment of the present invention, the injection rate Q of the main pump shaft seal riser is... D3 ,satisfy:

[0025]

[0026] Among them, L D3 S represents the change in liquid level in the main pump shaft seal riser. D3 Δt represents the cross-sectional area of ​​the main pump shaft seal riser, and Δt represents the test time.

[0027] In one embodiment of the present invention, the step of detecting the side leakage rate outside the primary loop pressure boundary includes:

[0028] Detect whether there is an identifiable leak outside the primary loop pressure boundary;

[0029] When an identifiable leak exists outside the primary loop pressure boundary, the side leakage rate outside the primary loop pressure boundary is obtained through detection.

[0030] When there is no identifiable leakage outside the primary circuit pressure boundary, the side leakage rate outside the primary circuit pressure boundary is 0.

[0031] In one embodiment of the present invention, the step of acquiring test data includes:

[0032] Measure the volume of the cooling medium in the test water tank and obtain the volume change of the test water tank in the test data;

[0033] The volume and density of the cooling medium in the first loop are measured, and the volume change of the cooling medium in the first loop under temperature change is calculated based on the volume and density of the cooling medium in the first loop and the preset leakage cooling medium density in the test data.

[0034] In one embodiment of the present invention, the step of calculating the overall leakage rate of the primary loop based on the test data and test duration includes:

[0035] Based on the volume change of the test water tank and the test duration in the test data, the leakage rate of the test water tank is calculated;

[0036] Based on the volume change of the cooling medium in the first loop under temperature change and the test duration in the test data, calculate the leakage rate of the cooling medium in the first loop under temperature change.

[0037] The overall leakage rate of the first circuit is obtained by subtracting the leakage rate of the test water tank from the leakage rate of the cooling medium corresponding to the temperature change in the first circuit.

[0038] In one embodiment of the present invention, the test water tank includes a tank body, and the leakage rate Q1 of the test water tank satisfies:

[0039]

[0040] Δt = t1 - t0;

[0041] Among them, S TANK L is the cross-sectional area of ​​the box. TANK0 , L TANK1 These are the liquid levels in the tank at the initial time t0 and the final time t1, respectively, and Δt represents the test time.

[0042] ρ tANK0 ρ represents the density of the cooling medium inside the box at the initial time t0; TANK1 ρ represents the density of the cooling medium inside the box at the final time t1. Leak This represents the preset leakage cooling medium density.

[0043] In one embodiment of the present invention, the test water tank further includes a booster pump, which forms a continuous water flow between the booster pump and the tank body. The primary circuit includes a voltage regulator, and the leakage rate Q2 of the cooling medium corresponding to the temperature change in the primary circuit satisfies:

[0044]

[0045] V LOOP =V Tot -V Pzr ; Δt = t1 - t0;

[0046] Where Δt represents the test time;

[0047] ρ LOOP0 ρ Pzr0 ρ TSD0 These represent the densities of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipe after pressurization by the booster pump, respectively, at the initial time t0.

[0048] ρ LOOP1 ρ Pzr1 ρ TSD1 ρ represents the density of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipe after pressurization by the booster pump, respectively, at the final time t1; Leak This is expressed as the preset leakage cooling medium density;

[0049] V Tot V represents the total volume of the cooling medium in the first loop. Pzr V represents the volume of the cooling medium inside the voltage regulator. LOOP V represents the volume of the cooling medium within the primary loop.TSD This represents the volume of the cooling medium in the corresponding pipeline after the pressurization pump has applied pressure.

[0050] In one embodiment of the present invention, the step of calculating the total leakage rate and the unidentifiable leakage rate of the primary loop based on the overall leakage rate, the identifiable leakage rate, and the side leakage rate includes:

[0051] Subtracting the overall leakage rate from the identifiable leakage rate yields the unidentifiable leakage rate of the first loop.

[0052] The total leakage rate of the first loop is obtained by subtracting the overall leakage rate from the side leakage rate.

[0053] In one embodiment of the present invention, the step of generating the test results of the first loop based on the total leakage rate and the unidentifiable leakage rate includes:

[0054] The total leakage rate is compared with a first preset threshold, and the unidentifiable leakage rate is compared with a second preset threshold.

[0055] When the total leakage rate is less than or equal to a first preset threshold and the unidentifiable leakage rate is less than or equal to a second preset threshold, a test pass result for the first loop is generated.

[0056] Otherwise, the test result for the aforementioned loop will be deemed unqualified.

[0057] In one embodiment of the present invention, the step of controlling the cooling medium to circulate within the test pipeline at a first preset pressure and detecting whether there is a leak at the primary loop pressure boundary includes:

[0058] The cooling medium is controlled to circulate within the test pipeline at a first preset pressure to detect whether there is any leakage at the primary loop pressure boundary.

[0059] When no leakage occurs at the primary circuit pressure boundary, the duration of the test test is controlled by circulating the cooling medium in the test pipeline at a second preset pressure.

[0060] When leakage occurs at the pressure boundary of the primary loop, a test failure result is generated for the primary loop.

[0061] This invention also proposes a primary loop leakage rate calculation system for nuclear power plants, in which a test water tank is connected between the lower leakage pipeline interface and the upper filling pipeline interface of the primary loop to form a test pipeline.

[0062] The system includes:

[0063] The first control unit is used to control the circulation of the cooling medium in the test pipeline under a first preset pressure, and to detect whether there is a leak at the primary loop pressure boundary.

[0064] The second control unit is used to control the duration of the cooling medium circulating in the test pipeline at a second preset pressure when no leakage occurs at the pressure boundary of the primary loop, detect whether there is an identifiable leakage in the primary loop, and obtain the identifiable leakage rate, the side leakage rate outside the pressure boundary of the primary loop, and test data; wherein, the first preset pressure is less than the second preset pressure, and the second preset pressure is the set acceptance pressure;

[0065] The first calculation unit is used to calculate the overall leakage rate of the first loop based on the test data and test duration.

[0066] The second calculation unit is used to calculate the total leakage rate and the unidentifiable leakage rate of the first loop based on the overall leakage rate, the identifiable leakage rate and the side leakage rate;

[0067] The generation unit is used to generate the test results of the first loop based on the total leakage rate and the unidentifiable leakage rate.

[0068] As described above, the present invention provides a method and system for calculating the primary loop leakage rate in a nuclear power plant. When the auxiliary systems of a nuclear power plant unit under construction are not yet completed and the primary loop leakage rate cannot be measured, a test water tank can be connected between the drain line interface and the charging line interface of the primary loop. Furthermore, the cooling medium between the primary loop and the test water tank is circulated at a lower first preset pressure to check for leaks. If leaks are found, relevant maintenance work can be performed. Subsequently, the cooling medium between the primary loop and the test water tank is circulated at a higher second preset pressure (acceptance pressure). The test results for the primary loop can be calculated and generated based on the total leakage and the unidentifiable leakage rate. Attached Figure Description

[0069] Figure 1 This is a flowchart illustrating a method for calculating the leakage rate of the primary loop in a nuclear power plant, as provided in an embodiment of the present invention.

[0070] Figure 2 This is a schematic diagram of the connection of a primary loop in a nuclear power plant, provided as an embodiment of the present invention.

[0071] Figure 3 This is an internal structural diagram of a test water tank provided in an embodiment of the present invention.

[0072] Figure 4 This is a structural block diagram of a nuclear power plant primary loop leakage rate calculation system provided in an embodiment of the present invention. Detailed Implementation

[0073] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0074] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0075] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0076] Please see Figures 1 to 4 This invention proposes a method and system for calculating the primary loop leakage rate of a nuclear power plant. It can be applied to the testing of the primary loop in pressurized water reactor (PWR) nuclear power plants, for example, in calculating the primary loop leakage during primary loop testing. When the auxiliary systems of a nuclear power plant under construction are not yet complete and the primary loop leakage rate cannot be measured, this invention utilizes a test water tank connected between the primary loop's drain line interface and charging line interface. Furthermore, the cooling medium between the primary loop and the test water tank circulates under a preset pressure, allowing for the calculation and analysis of the total leakage and unidentifiable leakage rate of the primary loop, thus completing the primary loop test. Detailed descriptions are provided below using specific embodiments.

[0077] Please see Figure 1 In one embodiment of the present invention, the present invention provides a method for calculating the leakage rate of the primary loop of a nuclear power plant, wherein a test water tank is connected between the lower leakage pipeline interface and the upper filling pipeline interface of the primary loop to form a test pipeline.

[0078] Specifically, such as Figure 2 As shown, a single loop can include three loops, each of which can independently form a circulating flow of the cooling medium. Figure 2The AA connection forms the first loop, the BB connection forms the second loop, and the CC connection forms the third loop. The primary loop may include a steam generator 100, a reactor coolant pump 110, a pressurizer 120, a drain line interface 130, a charge line interface 140, and a pressure vessel. For nuclear power units under construction, primary loop testing cannot be performed because the auxiliary systems cannot reach a fully usable state, which is detrimental to the project's progress.

[0079] To address the problems mentioned above, in this embodiment, as follows: Figure 2 and Figure 3 As shown, a test water tank is connected between the drain line interface 130 and the charging line interface 140 of the primary loop to form a test pipeline. The test water tank may include a control cabinet 150, a housing 160, and a pressure pump 170. The control cabinet 150 controls the stirring pump, pressure pump 170, and valves on the housing 160. Cooling medium is stored and flows within the housing 160. The pressure pump 170 pressurizes the cooling medium 170 so that the pressure of the pressurized cooling medium is the same as the pressure of the cooling medium in the primary loop. Figure 3 In the diagram, the red line indicates the flow direction of the cooling medium, which flows along the direction of the drain line interface 130, the housing 160, the pressure pump 170, and the charging line interface 140.

[0080] exist Figure 3 In this diagram, LP represents the local pressure gauge, MP represents the pressure gauge after pressurization by the pressure pump 170, MT represents the temperature sensor, MN represents the liquid level sensor, MD represents the flow sensor, and M represents the drive motor.

[0081] The method for calculating the primary loop leakage rate includes the following steps.

[0082] Step S10: Control the cooling medium to circulate in the test pipeline at a first preset pressure, and detect whether there is leakage at the primary loop pressure boundary.

[0083] Specifically, the first preset pressure can be 24.5 bar.g or 109 bar.g. The purpose of setting the first preset pressure is to detect leaks in the primary loop at a preset low pressure, but it is not required to calculate the leakage amount. Furthermore, at the first preset pressure, a comprehensive check must be conducted to identify any leaks at the pressure boundaries of the primary loop. For example, at the first preset pressure, all valves should be checked, and if a valve is found to be leaking, the leaking valve should be recorded and appropriate maintenance should be performed to prevent valve leakage problems from persisting to higher pressure conditions.

[0084] Step S20: When no leakage occurs at the primary circuit pressure boundary, control the cooling medium to circulate in the test pipeline for a test duration at the second preset pressure, detect whether there is an identifiable leakage in the primary circuit, and obtain the identifiable leakage rate, the side leakage rate outside the primary circuit pressure boundary, and test data; wherein, the first preset pressure is less than the second preset pressure, and the second preset pressure is the set acceptance pressure.

[0085] In one embodiment of the present invention, step S20, which involves controlling the duration of the test flow of the cooling medium in the test pipeline at a second preset pressure when no leakage occurs at the primary circuit pressure boundary, may include steps S2100, S2200, and S2300.

[0086] Step S2100: Control the cooling medium to circulate in the test pipeline at a first preset pressure, and detect whether there is leakage at the primary loop pressure boundary.

[0087] Step S2200: When no leakage occurs at the primary circuit pressure boundary, control the duration of the test test for the cooling medium to circulate in the test pipeline at the second preset pressure.

[0088] Step S2300: When leakage occurs at the pressure boundary of the primary loop, a test failure result for the primary loop is generated.

[0089] As can be seen from the above analysis, the purpose of setting the first preset pressure is to detect leakage in the primary circuit under the preset low pressure and take corresponding maintenance measures, thereby avoiding the valve leakage problem from being carried over to a higher pressure.

[0090] Therefore, when no leakage occurs at the primary loop pressure boundary, the cooling medium is circulated in the test pipeline for a controlled duration at a second preset pressure. The total leakage rate and unidentifiable leakage rate of the primary loop are then calculated at this second preset pressure. If leakage occurs at the primary loop pressure boundary, a test failure result for the primary loop is generated.

[0091] In one embodiment of the present invention, step S20, which involves detecting whether there is an identifiable leakage in the loop and obtaining the identifiable leakage rate, may include steps S240, S250, and S260.

[0092] Step S210: Detect whether there is an identifiable leak in the loop.

[0093] Step S220: When there is an identifiable leakage in the first loop, the identifiable leakage rate is obtained by detection.

[0094] Step S230: When there is no identifiable leakage in the first loop, the identifiable leakage rate is 0.

[0095] In one embodiment of the present invention, step S220 may include steps S2201 and S2202.

[0096] Step S2201: When there is an identifiable leak in the primary circuit and the main pump of the primary circuit is not equipped with a shaft seal riser, detect the leakage rate at the pressure boundary of the primary circuit and the side leakage rate outside the pressure boundary of the primary circuit.

[0097] Step S2202: Calculate the identifiable leakage rate of the first loop based on the leakage rate at the pressure boundary of the first loop and the side leakage rate outside the pressure boundary of the first loop.

[0098] Specifically, when the main pump (reactor coolant pump 110) is not equipped with a shaft seal riser, it indicates that there is no main pump shaft seal riser injection rate in the primary loop. At this time, the identifiable leakage rate of the primary loop can be calculated by the leakage rate at the pressure boundary of the primary loop and the side leakage rate outside the pressure boundary of the primary loop.

[0099] In this context, the primary loop pressure boundary refers to the boundary containing the reactor coolant, which in this embodiment can be considered as the primary loop. Outside the primary loop pressure boundary, in this embodiment, it can be considered as the test water tank.

[0100] In one embodiment of the present invention, step S220 may include steps S2203 and S2204.

[0101] Step S2203: When there is an identifiable leak in the primary circuit and the main pump of the primary circuit is equipped with a shaft seal riser, detect the leakage rate at the pressure boundary of the primary circuit, the side leakage rate outside the pressure boundary of the primary circuit, and the injection rate of the main pump shaft seal riser.

[0102] Step S2204: Calculate the identifiable leakage rate of the first circuit based on the leakage rate at the pressure boundary of the first circuit, the side leakage rate outside the pressure boundary of the first circuit, and the injection rate of the main pump shaft seal riser.

[0103] Specifically, when the main pump (reactor coolant pump 110) is equipped with a shaft seal riser, it indicates that the primary loop includes the main pump shaft seal riser injection rate. At this time, the identifiable leakage rate of the primary loop can be calculated by the leakage rate at the pressure boundary of the primary loop, the side leakage rate outside the pressure boundary of the primary loop, and the main pump shaft seal riser injection rate.

[0104] Specifically, the identifiable leakage rate Q of the primary loop. D0 ,satisfy:

[0105] Q D0 =Q D1 +Q D2 -Q D3 ;

[0106] Among them, Q D1 The leakage rate, Q, is expressed as the pressure boundary leakage rate of the primary loop. D2 Q is the side leakage rate outside the primary loop pressure boundary. D3 This is expressed as the injection rate of the main pump shaft seal riser.

[0107] In one embodiment of the present invention, the injection rate Q of the main pump shaft seal riser is... D3 ,satisfy:

[0108]

[0109] Among them, L D3 S represents the change in liquid level in the main pump shaft seal riser. d3 Δt represents the cross-sectional area of ​​the main pump shaft seal riser, and Δt represents the test time.

[0110] In one embodiment of the present invention, step S20, which involves detecting the side leakage rate outside the primary loop pressure boundary, includes steps S240, S250, and S260.

[0111] Step S240: Detect whether there is an identifiable leak outside the primary loop pressure boundary.

[0112] Step S250: When there is an identifiable leak outside the primary circuit pressure boundary, the side leakage rate outside the primary circuit pressure boundary is obtained by detection.

[0113] Step S260: When there is no identifiable leakage outside the primary circuit pressure boundary, the side leakage rate outside the primary circuit pressure boundary is 0.

[0114] In one embodiment of the present invention, step S20, the step of obtaining test data, includes steps S270 and S280.

[0115] Step S270: Measure the volume of the cooling medium in the test water tank and obtain the volume change of the test water tank in the test data.

[0116] Step S280: Measure the volume and density of the cooling medium in the first loop, and calculate the volume change of the cooling medium in the first loop under temperature change in the test data based on the volume and density of the cooling medium in the first loop and the preset leakage cooling medium density.

[0117] Step S30: Calculate the overall leakage rate of the primary circuit based on the test data and test duration.

[0118] In one embodiment of the present invention, step S30 may include steps S310, S320 and S330.

[0119] Step S310: Calculate the leakage rate of the test water tank based on the volume change of the test water tank and the test duration in the test data.

[0120] Specifically, the test water tank includes a tank body 160, and the leakage rate Q1 of the test water tank satisfies:

[0121]

[0122] Δt = t1 - t0;

[0123] Among them, S TANK L is the cross-sectional area of ​​the housing 160. TANK0 , L TANK1 These are the liquid levels in the tank 160 at the initial time t0 and the final time t1, respectively, and Δt represents the time of the test.

[0124] ρ TANK0 ρ represents the density of the cooling medium inside the housing 160 at the initial time t0; TANK1 ρ represents the density of the cooling medium inside the housing 160 at the final time t1; Leak This represents the preset leakage cooling medium density.

[0125] Where, ρ TANK0 ρ TANK1 The temperature and pressure of the cooling medium inside the housing 160 can be obtained by referring to a table. Since the cooling medium in the housing 160 circulates under the second preset pressure, the pressure of the cooling medium inside the housing 160 can be considered as the second preset pressure.

[0126] Step S320: Based on the volume change of the cooling medium corresponding to the temperature change in the first loop and the test duration in the test data, calculate the leakage rate of the cooling medium corresponding to the temperature change in the first loop.

[0127] Specifically, the test water tank also includes a booster pump 170, which forms a continuous water flow between the booster pump 170 and the tank body 160. The primary circuit includes a pressure regulator, and the leakage rate Q2 of the cooling medium in the primary circuit under temperature changes satisfies:

[0128]

[0129] V LOOP =V Tot -V Pzr ; Δt = t1 - t0;

[0130] Where Δt represents the test time;

[0131] ρ LOOP0 ρ Pzr0 ρTSD0 These represent the densities of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipeline after pressurization by the pressurizing pump, respectively, at the initial time t0.

[0132] Where, ρ LOOP0 ρ Pzr0 ρ TSD0 The temperatures and pressures of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipeline after pressurization by the booster pump can be obtained by referring to a table. Since the cooling medium in the primary loop circulates under a second preset pressure, the pressures of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipeline after pressurization by the booster pump can be considered as the second preset pressure.

[0133] ρ LOOP1 ρ Pzr1 ρ TSD1 ρ represents the density of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipe after pressurization by the booster pump, respectively, at the final time t1; Leak This represents the preset leakage cooling medium density.

[0134] Where, ρ LOOP1 ρ Pzr1 ρ TSD1 The temperatures and pressures of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipeline after pressurization by the booster pump can be obtained by referring to a table. Since the cooling medium in the primary loop circulates under a second preset pressure, the pressures of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipeline after pressurization by the booster pump can be considered as the second preset pressure.

[0135] V Tot V represents the total volume of the cooling medium in the first loop. Pzr V represents the volume of the cooling medium inside the voltage regulator. LOOP V represents the volume of the cooling medium within the primary loop. TSD This represents the volume of the cooling medium in the corresponding pipeline after the pressurization pump has applied pressure.

[0136] Step S330: Subtract the leakage rate of the test water tank from the leakage rate of the cooling medium corresponding to the temperature change in the first loop to obtain the overall leakage rate of the first loop.

[0137] Step S40: Calculate the total leakage rate and the unidentifiable leakage rate of the first loop based on the overall leakage rate, the identifiable leakage rate and the side leakage rate.

[0138] In one embodiment of the present invention, step S40 may include steps S410 and S420.

[0139] Step S410: Subtract the overall leakage rate from the identifiable leakage rate to obtain the unidentifiable leakage rate of the first loop.

[0140] Step S420: Subtract the overall leakage rate from the side leakage rate to obtain the total leakage rate of the first loop.

[0141] Step S50: Generate the test results of the first loop based on the total leakage rate and the unidentifiable leakage rate.

[0142] In one embodiment of the present invention, step S50 may include steps S510, S520 and S530.

[0143] Step S510: Compare the total leakage rate with a first preset threshold, and compare the unidentifiable leakage rate with a second preset threshold.

[0144] Step S520: When the total leakage rate is less than or equal to the first preset threshold and the unidentifiable leakage rate is less than or equal to the second preset threshold, a test pass result for the first loop is generated.

[0145] Step S530: Otherwise, generate a test failure result for the first loop.

[0146] Specifically, when the cooling medium in the primary circuit circulates under the second preset pressure, the primary circuit test is considered qualified only when the total leakage rate is less than or equal to the first preset threshold and the unidentifiable leakage rate is less than or equal to the second preset threshold, and a qualified test result for the primary circuit can be generated.

[0147] When the cooling medium in the primary circuit circulates under the second preset pressure, if the total leakage rate is greater than the first preset threshold, or the unidentifiable leakage rate is greater than the second preset threshold, it indicates that the primary circuit test is unqualified, and a primary circuit test failure result can be generated.

[0148] Please see Figure 4 In one embodiment of the present invention, a nuclear power plant primary loop leakage rate calculation system 200 is also proposed, wherein a test water tank is connected between the lower leakage pipeline interface 130 and the upper filling pipeline interface 140 of the primary loop to form a test pipeline. The calculation system 200 includes a first control unit 210, a second control unit 220, a first calculation unit 230, a second calculation unit 240, and a generation unit 250.

[0149] The first control unit 210 is used to control the cooling medium to circulate in the test pipeline under a first preset pressure, and to detect whether there is a leak at the primary loop pressure boundary.

[0150] The second control unit 220 is used to control the duration of the cooling medium circulating in the test pipeline at a second preset pressure when no leakage occurs at the pressure boundary of the primary loop, detect whether there is an identifiable leakage in the primary loop, and obtain the identifiable leakage rate, the side leakage rate outside the pressure boundary of the primary loop, and test data; wherein, the first preset pressure is less than the second preset pressure, and the second preset pressure is the set acceptance pressure.

[0151] The first calculation unit 230 is used to calculate the overall leakage rate of the primary loop based on the test data and test duration.

[0152] The second calculation unit 240 is used to calculate the total leakage rate and the unidentifiable leakage rate of the first loop based on the overall leakage rate, the identifiable leakage rate and the side leakage rate.

[0153] The generation unit 250 is used to generate the test results of the first loop based on the total leakage rate and the unidentifiable leakage rate.

[0154] In summary, the present invention discloses a method and system for calculating the primary loop leakage rate of a nuclear power plant. When the auxiliary systems of a nuclear power plant unit under construction are incomplete and the primary loop leakage rate cannot be measured, a test water tank can be connected between the drain line interface and the charging line interface of the primary loop. Furthermore, the cooling medium between the primary loop and the test water tank is circulated at a relatively low first preset pressure to check for leaks. Then, the cooling medium between the primary loop and the test water tank is circulated at a higher second preset pressure (acceptance pressure), allowing the calculation of the total leakage and the unidentifiable leakage rate of the primary loop, generating the test results for the primary loop. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0155] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for calculating the leakage rate of the primary loop in a nuclear power plant, characterized in that, A test water tank is connected between the discharge pipeline interface and the charging pipeline interface of the primary loop to form a test pipeline; The method comprises: The cooling medium is controlled to circulate in the test pipeline at a first preset pressure to detect whether there is leakage at the primary loop pressure boundary. When no leakage occurs at the pressure boundary of the primary loop, the cooling medium is controlled to circulate in the test pipeline for a test duration at a second preset pressure to detect whether there is an identifiable leakage in the primary loop, and to obtain the identifiable leakage rate, the side leakage rate outside the pressure boundary of the primary loop, and test data; wherein, the first preset pressure is less than the second preset pressure, and the second preset pressure is the set acceptance pressure; Based on the test data and test duration, calculate the overall leakage rate of the primary loop; The total leakage rate and the unidentifiable leakage rate of the primary loop are calculated based on the overall leakage rate, the identifiable leakage rate, and the side leakage rate. The test results for the first loop are generated based on the total leakage rate and the unidentifiable leakage rate.

2. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 1, characterized in that, The step of detecting whether there is an identifiable leakage in the first loop and obtaining the identifiable leakage rate includes: Detect whether there is an identifiable leak in the primary loop: When an identifiable leak exists in the first loop, the identifiable leak rate is obtained through detection. When there is no identifiable leakage in the loop, the identifiable leakage rate is 0.

3. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 2, characterized in that, The step of obtaining the identifiable leakage rate by detection when an identifiable leakage exists in the first loop includes: When there is an identifiable leak in the primary circuit, and the main pump of the primary circuit is not equipped with a shaft seal riser, the leakage rate at the pressure boundary of the primary circuit and the side leakage rate outside the pressure boundary of the primary circuit are detected. The identifiable leakage rate of the first loop is calculated based on the leakage rate at the pressure boundary of the first loop and the side leakage rate outside the pressure boundary of the first loop.

4. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 2, characterized in that, The step of obtaining the identifiable leakage rate by detection when an identifiable leakage exists in the first loop includes: When there is an identifiable leak in the primary circuit and the main pump of the primary circuit is equipped with a shaft seal riser, the leakage rate at the pressure boundary of the primary circuit, the side leakage rate outside the pressure boundary of the primary circuit, and the injection rate of the main pump shaft seal riser are detected. The identifiable leakage rate of the first circuit is calculated based on the leakage rate at the pressure boundary of the first circuit, the side leakage rate outside the pressure boundary of the first circuit, and the injection rate of the main pump shaft seal riser.

5. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 4, characterized in that, The identifiable leakage rate Q of the first loop D0 ,satisfy: Q D0 =Q D1 +Q D2 -Q D3 ; Among them, Q D1 The leakage rate, Q, is expressed as the pressure boundary leakage rate of the primary loop. D2 Q is the side leakage rate outside the primary loop pressure boundary. D3 This is expressed as the injection rate of the main pump shaft seal riser.

6. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 5, characterized in that, The injection rate Q of the main pump shaft seal pipe D3 ,satisfy: Among them, L D3 S represents the change in liquid level in the main pump shaft seal riser. D3 Δt represents the cross-sectional area of ​​the main pump shaft seal riser, and Δt represents the test time.

7. The method for calculating the leakage rate of the primary loop of a nuclear power plant according to claim 3 or 4, characterized in that, The step of detecting the side leakage rate outside the primary loop pressure boundary includes: Detect whether there is an identifiable leak outside the primary loop pressure boundary; When an identifiable leak exists outside the primary loop pressure boundary, the side leakage rate outside the primary loop pressure boundary is obtained through detection. When there is no identifiable leakage outside the primary circuit pressure boundary, the side leakage rate outside the primary circuit pressure boundary is 0.

8. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 1, characterized in that, The steps for obtaining experimental data include: Measure the volume of the cooling medium in the test water tank and obtain the volume change of the test water tank in the test data; The volume and density of the cooling medium in the first loop are measured, and the volume change of the cooling medium in the first loop under temperature change is calculated based on the volume and density of the cooling medium in the first loop and the preset leakage cooling medium density in the test data.

9. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 1, characterized in that, The step of calculating the overall leakage rate of the primary loop based on the test data and test duration includes: Based on the volume change of the test water tank and the test duration in the test data, the leakage rate of the test water tank is calculated; Based on the volume change of the cooling medium in the first loop under temperature change and the test duration in the test data, calculate the leakage rate of the cooling medium in the first loop under temperature change. The overall leakage rate of the first circuit is obtained by subtracting the leakage rate of the test water tank from the leakage rate of the cooling medium corresponding to the temperature change in the first circuit.

10. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 9, characterized in that, The test water tank includes a tank body, and the leakage rate Q1 of the test water tank satisfies: Δt = t1 - t0; Among them, S TANK L is the cross-sectional area of ​​the box. TANK0 , L TANK1 These are the liquid levels in the tank at the initial time t0 and the final time t1, respectively, and Δt represents the test time. ρ TANK0 ρ represents the density of the cooling medium inside the box at the initial time t0; TANK1 ρ represents the density of the cooling medium inside the box at the final time t1. Leak This represents the preset leakage cooling medium density.

11. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 9, characterized in that, The test water tank also includes a booster pump, which forms a continuous water flow between the booster pump and the tank body. The primary circuit includes a voltage regulator, and the leakage rate Q2 of the cooling medium in the primary circuit under temperature changes satisfies: V LOOP =V Tot -V Pzr ;Δt=t1-t0; Where Δt represents the test time; ρ LOOP0 ρ Pzr0 ρ TSD0 These represent the densities of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipe after pressurization by the booster pump, respectively, at the initial time t0. ρ LOOP1 ρ Pzr1 ρ TSD1 ρ represents the density of the cooling medium in the primary loop, the cooling medium in the voltage regulator, and the cooling medium in the corresponding pipe after pressurization by the booster pump, respectively, at the final time t1; Leak This is expressed as the preset leakage cooling medium density; V Tot V represents the total volume of the cooling medium in the first loop. Pzr V represents the volume of the cooling medium inside the voltage regulator. LOOP V represents the volume of the cooling medium within the primary loop. TSD This represents the volume of the cooling medium in the corresponding pipeline after the pressurization pump has applied pressure.

12. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 1, characterized in that, The step of calculating the total leakage rate and the unidentifiable leakage rate of the first loop based on the overall leakage rate, the identifiable leakage rate, and the side leakage rate includes: Subtracting the overall leakage rate from the identifiable leakage rate yields the unidentifiable leakage rate of the first loop. The total leakage rate of the first loop is obtained by subtracting the overall leakage rate from the side leakage rate.

13. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 1, characterized in that, The step of generating the test results for the first loop based on the total leakage rate and the unidentifiable leakage rate includes: The total leakage rate is compared with a first preset threshold, and the unidentifiable leakage rate is compared with a second preset threshold. When the total leakage rate is less than or equal to a first preset threshold and the unidentifiable leakage rate is less than or equal to a second preset threshold, a test pass result for the first loop is generated. Otherwise, the test result for the aforementioned loop will be deemed unqualified.

14. The method for calculating the leakage rate of the primary loop in a nuclear power plant according to claim 1, characterized in that, The step of controlling the cooling medium to circulate within the test pipeline at a first preset pressure and detecting whether there is a leak at the primary loop pressure boundary includes: The cooling medium is controlled to circulate within the test pipeline at a first preset pressure to detect whether there is any leakage at the primary loop pressure boundary. When no leakage occurs at the primary circuit pressure boundary, the duration of the test test is controlled by circulating the cooling medium in the test pipeline at a second preset pressure. When leakage occurs at the pressure boundary of the primary loop, a test failure result is generated for the primary loop.

15. A system for calculating the leakage rate of the primary loop in a nuclear power plant, characterized in that, A test water tank is connected between the discharge pipeline interface and the charging pipeline interface of the primary loop to form a test pipeline; The system includes: The first control unit is used to control the circulation of the cooling medium in the test pipeline under a first preset pressure, and to detect whether there is a leak at the primary loop pressure boundary. The second control unit is used to control the duration of the cooling medium circulating in the test pipeline at a second preset pressure when no leakage occurs at the pressure boundary of the primary loop, detect whether there is an identifiable leakage in the primary loop, and obtain the identifiable leakage rate, the side leakage rate outside the pressure boundary of the primary loop, and test data; wherein, the first preset pressure is less than the second preset pressure, and the second preset pressure is the set acceptance pressure; The first calculation unit is used to calculate the overall leakage rate of the first loop based on the test data and test duration. The second calculation unit is used to calculate the total leakage rate and the unidentifiable leakage rate of the first loop based on the overall leakage rate, the identifiable leakage rate and the side leakage rate; The generation unit is used to generate the test results of the first loop based on the total leakage rate and the unidentifiable leakage rate.

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