Method, apparatus and device for detecting defects in a reactor vessel core barrel

Abstract

The application relates to a method and device for detecting defects of a reactor core barrel in a reactor pressure vessel, computer equipment, a storage medium and a computer program product. The method comprises the following steps: determining a preset defect depth value as a defect depth value of a defect of a reactor core barrel in a reactor pressure vessel; determining a first stress intensity factor of the defect based on the defect depth value and a preconfigured pressure value; performing plastic correction on the first stress intensity factor to obtain a second stress intensity factor according to a material yield strength and the defect depth value; when the second stress intensity factor does not meet a preset matching relationship with a reference fracture toughness limit value, updating the defect depth value, and performing the step of determining the first stress intensity factor of the defect based on the defect depth value and the preconfigured pressure value until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit value, so that a limit defect depth value capable of being detected by a primary loop water pressure test is obtained. The method can save reactor nuclear power unit operation resources.

Description

Technical Field

[0001] This application relates to the field of pressure vessel technology, and in particular to a method, apparatus, computer equipment, storage medium and computer program product for detecting defects in the core cylinder of a reactor pressure vessel. Background Technology

[0002] In the nuclear power field, the primary loop hydrostatic test is a strength hydrostatic test conducted on the high-pressure parts of the reactor, coolant system (RCP system), and related auxiliary systems at a suitable test pressure. This test is to check the sealing and welding quality of the primary loop equipment and piping, verify its sealing performance and safety under pressure, and thus prove that the reactor primary loop system is safe under normal operation and design accident conditions and meets nuclear safety regulations from the end of this test until the next test.

[0003] However, the primary circuit hydrostatic test will take up about 6 days of overhaul time for the reactor nuclear power unit, which consumes a lot of resources. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, computer equipment, computer-readable storage medium, and computer program product for detecting defects in the core shell of a reactor pressure vessel that can save resources, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for detecting defects in the core shell of a reactor pressure vessel, including:

[0006] Obtain a preset defect depth value, and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor;

[0007] Based on the defect depth value and the pre-configured pressure value, a first stress intensity factor for the defect is determined; the pre-configured pressure value characterizes the pressure during the primary loop hydrostatic test of the reactor.

[0008] The yield strength of the core cylinder material is obtained, and the first stress intensity factor is plastically corrected based on the yield strength and the defect depth value to obtain the second stress intensity factor.

[0009] A reference fracture toughness limit is determined for the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed.

[0010] When the second stress intensity factor does not meet the preset matching relationship with the reference fracture toughness limit, the defect depth value is updated according to the second stress intensity factor and the reference fracture toughness limit. The step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value is performed until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit, and the limit defect depth value that can be detected by the first-loop hydrostatic test is obtained.

[0011] Secondly, this application also provides a defect detection device for the core shell of a reactor pressure vessel, comprising:

[0012] The defect depth management module is used to obtain a preset defect depth value and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor.

[0013] The stress intensity factor management module is used to determine the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value; the pre-configured pressure value represents the pressure when the reactor undergoes a primary loop hydrostatic test; the module obtains the material yield strength of the core shell, and performs plastic correction on the first stress intensity factor according to the material yield strength and the defect depth value to obtain the second stress intensity factor;

[0014] The fracture toughness limit management module is used to determine the reference fracture toughness limit of the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed.

[0015] The defect depth management module is further configured to update the defect depth value according to the second stress intensity factor and the reference fracture toughness limit when the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, and execute the step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value, until the second stress intensity factor and the reference fracture toughness limit meet the preset matching relationship, thereby obtaining the limit defect depth value that can be detected by the primary hydrostatic test.

[0016] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0017] Obtain a preset defect depth value, and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor;

[0018] Based on the defect depth value and the pre-configured pressure value, a first stress intensity factor for the defect is determined; the pre-configured pressure value characterizes the pressure during the primary loop hydrostatic test of the reactor.

[0019] The yield strength of the core cylinder material is obtained, and the first stress intensity factor is plastically corrected based on the yield strength and the defect depth value to obtain the second stress intensity factor.

[0020] A reference fracture toughness limit is determined for the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed.

[0021] When the second stress intensity factor does not meet the preset matching relationship with the reference fracture toughness limit, the defect depth value is updated according to the second stress intensity factor and the reference fracture toughness limit. The step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value is performed until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit, and the limit defect depth value that can be detected by the first-loop hydrostatic test is obtained.

[0022] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps:

[0023] Obtain a preset defect depth value, and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor;

[0024] Based on the defect depth value and the pre-configured pressure value, a first stress intensity factor for the defect is determined; the pre-configured pressure value characterizes the pressure during the primary loop hydrostatic test of the reactor.

[0025] The yield strength of the core cylinder material is obtained, and the first stress intensity factor is plastically corrected based on the yield strength and the defect depth value to obtain the second stress intensity factor.

[0026] A reference fracture toughness limit is determined for the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed.

[0027] When the second stress intensity factor does not meet the preset matching relationship with the reference fracture toughness limit, the defect depth value is updated according to the second stress intensity factor and the reference fracture toughness limit. The step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value is performed until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit, and the limit defect depth value that can be detected by the first-loop hydrostatic test is obtained.

[0028] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, performs the following steps:

[0029] Obtain a preset defect depth value, and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor;

[0030] Based on the defect depth value and the pre-configured pressure value, a first stress intensity factor for the defect is determined; the pre-configured pressure value characterizes the pressure during the primary loop hydrostatic test of the reactor.

[0031] The yield strength of the core cylinder material is obtained, and the first stress intensity factor is plastically corrected based on the yield strength and the defect depth value to obtain the second stress intensity factor.

[0032] A reference fracture toughness limit is determined for the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed.

[0033] When the second stress intensity factor does not meet the preset matching relationship with the reference fracture toughness limit, the defect depth value is updated according to the second stress intensity factor and the reference fracture toughness limit. The step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value is performed until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit, and the limit defect depth value that can be detected by the first-loop hydrostatic test is obtained.

[0034] The aforementioned defect detection method, apparatus, computer equipment, storage medium, and computer program product for the reactor core cylinder in the reactor pressure vessel determines a first stress intensity factor for the defect by using the defect depth value of the defect in the reactor core cylinder and the pressure value during the primary circuit hydrostatic test. After plastic correction, a second stress intensity factor is obtained. A reference fracture toughness limit is determined based on the test temperature value during the primary circuit hydrostatic test. When the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, the defect depth value is iteratively updated until the second stress intensity factor and the reference fracture toughness limit no longer meet the preset matching relationship. This yields the limit defect depth value that can be detected by the primary circuit hydrostatic test. Technicians can determine the necessity of conducting the primary circuit hydrostatic test based on the limit defect depth value, thus saving reactor nuclear power unit operating resources. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart illustrating a defect detection method for the core cylinder in a reactor pressure vessel, as shown in one embodiment.

[0037] Figure 2 This is a simplified flowchart illustrating the detection capability assessment of a primary loop hydrostatic test in one embodiment.

[0038] Figure 3 This is a structural block diagram of a defect detection device for the core cylinder in a reactor pressure vessel, as shown in one embodiment.

[0039] Figure 4 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0041] In one embodiment, such as Figure 1As shown, a method for detecting defects in the core shell of a reactor pressure vessel is provided. This embodiment illustrates the application of this method to a computer device. The computer device can be a terminal or a server. It is understood that this method can also be applied to a system including a terminal and a server, and implemented through interaction between the terminal and the server. The terminal can be a personal computer, laptop, smartphone, or tablet. The server can be a standalone server or a server cluster consisting of multiple servers. In this embodiment, the method includes the following steps:

[0042] Step 102: Obtain the preset defect depth value and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor.

[0043] A reactor is a device capable of sustaining a controlled, self-sustaining chain reaction of nuclear fission to achieve nuclear energy utilization. The reactor's pressure vessel is a sealed container that houses the reactor and withstands enormous operating pressures. The pressure vessel secures and encloses the reactor core and internal components, confining the fission reaction of the nuclear fuel within a sealed space. The core shell is a vertical cylindrical structure including a bottom wall and side walls. As a component of the pressure vessel, it houses fuel assemblies, control rod assemblies, etc. The bottom and side walls of the core shell can be referred to as the core shell walls.

[0044] A defect is a simulated crack on the inner surface of the reactor core. The defect depth is the depth to which the defect penetrates into the core wall. The defect depth value is a range of possible values. A preset defect depth value is a pre-set defect depth value. Specifically, the preset defect depth value is the initial defect depth value before updating the original defect depth value. The preset defect depth value can be any value within a specified range, greater than zero and not greater than half the initial thickness of the core wall. Half the initial thickness of the core wall is approximately 100 mm. For example, the preset defect depth value can be 1 mm, 10 mm, 20 mm, or others.

[0045] Step 104: Determine the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value; the pre-configured pressure value characterizes the pressure during the primary loop hydrostatic test of the reactor.

[0046] The primary loop hydrostatic test involves pressurizing water to test the pressure resistance of relevant equipment, pipelines, valves, and pressure vessels in the primary loop of a nuclear power plant. The primary loop of a nuclear power plant mainly consists of the reactor, coolant system, steam generator, and main steam pipeline.

[0047] The pressure applied during the primary circuit hydrostatic test is the pressure exerted on the core shell of the pressure vessel during the primary circuit hydrostatic test. The pre-configured pressure value is the pressure taken during the primary circuit hydrostatic test. The pre-configured pressure value can be 1.2 times the design pressure value of the pressure vessel. The design pressure value is the set maximum pressure value at the top of the pressure vessel, not lower than the working pressure value of the pressure vessel. For example, if the design pressure value is 172.3 (the physical unit is pressure bar), then the pre-configured pressure value could be 206.76, approximately 207. The stress intensity factor is a physical quantity reflecting the strength of the elastic stress field at the tip of a defect. The first stress intensity is the stress intensity factor before plastic correction.

[0048] In one embodiment, the computer device can determine a third stress intensity factor of the defect under unit pressure based on the defect depth value, and determine a first stress intensity factor of the defect based on the third stress intensity factor and a pre-configured pressure value.

[0049] Step 106: Obtain the material yield strength of the core cylinder. Based on the material yield strength and the defect depth value, perform plastic correction on the first stress intensity factor to obtain the second stress intensity factor.

[0050] Among them, the material yield strength is the yield limit of the metallic material in the reactor core when it yields, that is, the stress that resists a small amount of plastic deformation. Plasticity correction is based on the characteristics of the plastic zone at the tip of the defect, and corrects the stress intensity factor calculated according to linear elastic fracture mechanics to a value closer to reality.

[0051] In one embodiment, the computer device can obtain the yield strength of the core cylinder material, determine the radius value of the plastic zone at the tip of the defect based on the yield strength and the first stress intensity factor, and perform plastic correction on the first stress intensity factor based on the radius value and the defect depth value to obtain the second stress intensity factor.

[0052] Step 108: Determine the reference fracture toughness limit of the core tube. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core tube. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core tube and the test temperature value during the primary circuit hydrostatic test.

[0053] The reference fracture toughness limit characterizes the ability of the material in the reactor core to prevent defect propagation. The brittle fracture toughness limit characterizes the ability of the material in the reactor core to prevent defect propagation leading to brittle fracture. Before brittle fracture, the material does not exhibit significant plastic deformation, and as the defect propagates, it can instantaneously expand to the entire structure, causing fracture. The ductile fracture toughness limit characterizes the ability of the material in the reactor core to prevent defect propagation leading to ductile fracture. Before ductile fracture, the material exhibits significant plastic deformation.

[0054] The core shell material can include copper, phosphorus, etc. The test temperature value during the primary circuit hydrostatic test is the temperature value of the pressure vessel during the primary circuit hydrostatic test. The test temperature value can be the design temperature value of the pressure vessel or a temperature value within a preset temperature range.

[0055] In one embodiment, the computer equipment can determine the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder based on the material type of the core cylinder and the test temperature value during the primary circuit hydrostatic test, and determine the fracture reference toughness limit of the core cylinder based on the brittle fracture toughness limit and the ductile fracture toughness limit.

[0056] In one embodiment, the computer equipment can determine the irradiation embrittlement transition reference temperature of the core cylinder based on the neutron flux of the reactor, the mass percentage of the first type of material in the core cylinder material type, and the mass percentage of the second type of material in the material type, and determine the brittle fracture toughness limit of the core cylinder based on the test temperature value and the irradiation embrittlement transition reference temperature of the core cylinder.

[0057] In one embodiment, the computer device can determine the ductile fracture toughness limit of the core shell based on the test temperature value and the mass percentage of the third type of material in the material type.

[0058] Step 110: When the second stress intensity factor does not meet the preset matching relationship with the reference fracture toughness limit, update the defect depth value according to the second stress intensity factor and the reference fracture toughness limit, and perform the step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit, and obtain the limit defect depth value that can be detected by the primary hydrostatic test.

[0059] The preset matching relationship is a pre-defined relationship between the second stress intensity factor and the reference fracture toughness limit. The preset matching relationship can be that the second stress intensity factor is equal to the reference fracture toughness limit, or that the second stress intensity factor is less than the reference fracture toughness limit, and the absolute value of the difference between the second stress intensity factor and the reference fracture toughness limit is not greater than a preset difference value. The preset difference value can be 0.1, 1, or other values.

[0060] The ultimate defect depth is the depth of a defect in the reactor core tube during a primary coolant hydrostatic test, at which critical instability propagation occurs. When the defect depth exceeds the ultimate defect depth, instability propagation will occur in the core tube, meaning the core material will fracture. Since the aforementioned defects are simulated within the core tube, the ultimate defect depth can be determined iteratively by updating the defect depth values. It is understandable that if there is a significant difference between the actual defects present in the core tube and the ultimate defect depth, a primary coolant hydrostatic test may not be performed, thus saving costs.

[0061] In one embodiment, when the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, the defect depth value is updated according to the second stress intensity factor and the reference fracture toughness limit, and steps 104 to 108 are executed until the second stress intensity factor and the reference fracture toughness limit meet the preset matching relationship. The defect depth value when the second stress intensity factor and the reference fracture toughness limit meet the preset matching relationship is determined as the limit defect depth value that can be detected by the primary hydrostatic test.

[0062] In one embodiment, when the second stress intensity factor and the reference fracture toughness limit do not meet a preset matching relationship, the magnitude comparison result between the second stress intensity factor and the reference fracture toughness limit is obtained, and the defect depth value is updated according to the magnitude comparison result within the depth value range. The magnitude comparison result is obtained by comparing the magnitudes of the second stress intensity factor and the reference fracture toughness limit.

[0063] In one embodiment, the step of updating the defect depth value within the depth range according to the size comparison result includes: when the size comparison result indicates that the second stress intensity factor is greater than the reference fracture toughness limit, updating the defect depth value within the depth range along the direction of decreasing the defect depth value; when the size comparison result indicates that the second stress intensity factor is less than the reference fracture toughness limit, updating the defect depth value within the depth range along the direction of increasing the defect depth value.

[0064] In the aforementioned defect detection method for the core cylinder of a reactor pressure vessel, a first stress intensity factor is determined by using the defect depth value of the core cylinder in the reactor pressure vessel and the pressure value during the primary circuit hydrostatic test. This is followed by plastic correction to obtain a second stress intensity factor. A reference fracture toughness limit is determined based on the test temperature value during the primary circuit hydrostatic test. When the second stress intensity factor and the reference fracture toughness limit do not meet a preset matching relationship, the defect depth value is iteratively updated until the second stress intensity factor and the reference fracture toughness limit no longer meet the preset matching relationship. This yields the limit defect depth value that can be detected by the primary circuit hydrostatic test. Technicians can determine the necessity of conducting the primary circuit hydrostatic test based on the limit defect depth value, thus saving reactor nuclear power unit operating resources.

[0065] In one embodiment, step 104 may include the following steps: obtaining the initial thickness value of the cylinder wall where the defect is located in the core cylinder; determining the remaining thickness value of the cylinder wall based on the initial thickness value and the defect depth value; determining the third stress intensity factor of the defect under unit pressure based on the defect depth value and the remaining thickness value; and determining the first stress intensity factor of the defect based on the third stress intensity factor and a pre-configured pressure value.

[0066] The initial thickness of the cylinder wall is the thickness of the cylinder wall when there are no defects. The remaining thickness is the initial thickness minus the defect depth.

[0067] In this embodiment, by determining the defect depth value and the remaining thickness value, the third stress intensity factor is determined. Then, based on the third stress intensity factor and the pre-configured pressure value, the first stress intensity factor of the defect is determined. Thus, combined with subsequent steps, the ultimate defect depth value can be determined, creating conditions for saving nuclear power unit resources.

[0068] In one embodiment, the step of determining the third stress intensity factor of the defect under unit pressure based on the defect depth value and the remaining thickness value includes: obtaining a preset shape influence coefficient and a stress fitting coefficient, wherein the stress fitting coefficient is determined based on the respective tip depth value and the respective tip stress value of multiple tip points on the defect propagation path; determining the third stress intensity factor of the defect under unit pressure based on the defect depth value, the remaining thickness value, the preset shape influence coefficient, and the stress fitting coefficient; the third stress intensity factor is positively correlated with the preset shape influence coefficient and the stress fitting coefficient.

[0069] The preset shape influence coefficient is the shape influence coefficient corresponding to the shape of the defect in the core shell. When the defect is an elliptical crack, the preset shape influence coefficient can be determined according to the influence function of elliptical cracks as described in the RCC-M specification (French Code for Design and Construction of Mechanical Equipment in Pressurized Water Reactors).

[0070] The tip is a data point taken at different locations along the defect's propagation path. The propagation path refers to the path the defect grows within the reactor core. The tip depth is the distance between the tip and the surface of the core wall where the defect is located; specifically, it can be the shortest straight-line distance between the tip and the surface of the core wall where the defect is located. The tip stress is the stress value at the tip along the normal direction of the defect surface. The tip stress value can be calculated using finite element analysis. The defect surface is the region of the defect within the surface of the core wall where it is located.

[0071] In this embodiment, based on the defect depth value, remaining thickness value, preset shape influence coefficient and stress fitting coefficient, the third stress intensity factor of the defect under unit pressure is determined. Then, combined with subsequent steps, the ultimate defect depth value can be determined, creating conditions for saving nuclear power unit resources.

[0072] In one embodiment, there may be five tip points. In this embodiment, the computer device can determine the remaining thickness value of the cylinder wall, determine the tip depth value and the tip stress value of each of the multiple tip points on the expansion path of the defect, and perform polynomial fitting based on the remaining thickness value, the tip depth value and the tip stress value of each of the multiple tip points and the following formula (1) to perform polynomial fitting on the stress distribution on the structural wall thickness at the location of the defect and obtain the stress fitting coefficient.

[0073]

[0074] Among them, σ0, σ1, σ2, σ3, and σ4 can be characterized as stress fitting coefficients. When performing polynomial fitting, for each tip point, the tip depth value of the targeted tip point is substituted into u in formula (1), the tip stress value of the targeted tip point is substituted into σ in formula (1), and the remaining thickness value is substituted into L in formula (1) to obtain the polynomial corresponding to the targeted tip point with σ0, σ1, σ2, σ3, and σ4 as variables. Thus, the polynomials corresponding to multiple tip points with σ0, σ1, σ2, σ3, and σ4 as variables can be obtained. Therefore, the specific values ​​of σ0, σ1, σ2, σ3, and σ4 can be obtained by solving the polynomial fitting problem.

[0075] In one embodiment, the computer device may determine the third stress intensity factor based on the defect depth value, the remaining thickness value, the preset shape influence coefficient and the stress fitting coefficient, according to the following formula (2).

[0076]

[0077] Among them, K ImThe third stress intensity factor can be represented. i0, i1, i2, and i3 can represent preset shape influence coefficients, which can be determined according to the influence function of elliptical cracks at the core shell in the RCC-M specification. The specific values ​​of the stress fitting coefficients σ0, σ1, σ2, and σ3 can be obtained through the above polynomial fitting. 'a' can be used to substitute the defect depth value, and 'L' can be used to substitute the initial thickness value. The defect depth value is less than the remaining thickness value, and the remaining thickness value is less than the initial thickness value.

[0078] In one embodiment, the computer device may determine the first stress intensity factor of the defect based on the third stress intensity factor and the pre-configured pressure value, according to the following formula (3).

[0079] K I =P×K Im Formula (3)

[0080] Among them, K I The first stress intensity factor can be represented by P, which can represent the pre-configured pressure value. The third stress intensity factor can be the product of the first stress intensity factor and the pre-configured pressure value.

[0081] In one embodiment, step 106, which involves plastically correcting the first stress intensity factor based on the material yield strength and the defect depth value to obtain the second stress intensity factor, includes: determining the radius of the plastic zone at the tip of the defect based on the material yield strength and the first stress intensity factor; the radius value and the ratio between the first stress intensity factor and the material yield strength are positively correlated; determining a correction coefficient based on the numerical comparison results of the radius value with a first reference value and a second reference value; the first and second reference values ​​are determined based on the defect depth value, and the second reference value is greater than the first reference value; and plastically correcting the first stress intensity factor based on the radius value, the correction coefficient, and the defect depth value to obtain the second stress intensity factor.

[0082] The tip of the defect is the edge of the defect extending into the cylinder wall. The plastic zone at the tip of the defect is the area of ​​plastic deformation that occurs at the tip after the defect is subjected to force. The radius of the plastic zone is its specific value. The first and second reference values ​​can be determined based on the difference between the initial thickness and the defect depth, that is, the first and second reference values ​​can be determined based on the remaining thickness. The numerical comparison result is obtained by comparing the radius value with the first and second reference values ​​respectively.

[0083] In this embodiment, the first stress intensity factor is plastically corrected based on the radius value, correction coefficient, and defect depth value of the plastic zone at the tip, resulting in a second stress intensity factor that is closer to the actual situation. Combined with subsequent steps, a more accurate limit defect depth value can be determined, creating conditions for saving nuclear power unit resources.

[0084] In one embodiment, the computer device may determine the second stress intensity factor based on the radius value, the correction factor, the defect depth value, and the first stress intensity factor, according to the following formula (4).

[0085]

[0086] Among them, K cp This can characterize the second stress intensity factor. The second stress intensity factor can be the product of a correction coefficient, the first stress intensity factor, and a formula. The formula is the square root of the ratio between the sum of the defect depth and radius values ​​and the defect depth value.

[0087] r y The radius of the plastic zone at the tip of the defect can characterize the defect. S y It can characterize the yield strength of a material. α can characterize the correction factor, and α can be determined based on r. y The value is determined by comparing it with the values ​​of the first reference value and the second reference value, respectively. Specifically, the first reference value can be 0.05(ta), and the second reference value can be 0.12(ta). t represents the initial thickness of the cylinder wall, and (ta) represents the remaining thickness of the cylinder wall. Therefore, the first reference value can be 0.05 times the remaining thickness value, and the second reference value can be 0.12 times the remaining thickness value; when r y When the radius value represented by the numerical comparison result is not greater than the first reference value, the value of α can be 1; when 0.05(ta) < r y ≤0.12(ta), meaning the numerical comparison result indicates that the radius value is greater than the first reference value but not greater than the second reference value. The value of α is positively correlated with the radius value; when r y >0.12(ta), meaning that when the numerical comparison result represents a radius value greater than the second reference value, the value of α can be 1.6.

[0088] In one embodiment, the step of determining the reference fracture toughness limit of the core cylinder in step 108 includes: obtaining a preset test temperature value, using the preset test temperature value as the test temperature value when conducting the primary circuit hydrostatic test; determining the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder according to the material type of the core cylinder and the test temperature value, and determining the reference fracture toughness limit of the core cylinder according to the brittle fracture toughness limit and the ductile fracture toughness limit.

[0089] The defect detection method for the core shell of the reactor pressure vessel mentioned above further includes the following steps: when the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, the test temperature value is updated within the preset temperature range according to the second stress intensity factor and the reference fracture toughness limit, and the steps of determining the brittle fracture toughness limit and ductile fracture toughness limit of the core shell according to the material type of the core shell and the test temperature value are executed; when the test temperature value has been updated within the preset temperature range, and there is no reference fracture toughness limit that meets the preset matching relationship with the second stress intensity factor, the step of updating the defect depth value according to the second stress intensity factor and the reference fracture toughness limit is triggered.

[0090] The preset test temperature value is a pre-set test temperature value, specifically the initial test temperature value before updating the test temperature value. The preset temperature range is a pre-set temperature range. Technicians can set the preset temperature range according to the historical variation range of test temperature values ​​during actual primary circuit hydrostatic testing. For example, the preset temperature range can be 60 to 100℃ (degrees Celsius).

[0091] In this embodiment, the test temperature value is updated within a preset temperature range, thereby updating the reference fracture toughness limit. Then, the second stress intensity factor is matched with the reference fracture toughness limit to determine whether it meets the preset matching relationship. This can simulate the change of the test temperature value during the actual primary hydrostatic test and more accurately determine the defect depth value.

[0092] In one embodiment, the computer equipment can acquire a preset test temperature value and use it as the test temperature value for the primary circuit hydrostatic test; based on the material type of the core shell and the test temperature value, determine the brittle fracture toughness limit and the ductile fracture toughness limit of the core shell, and based on the brittle fracture toughness limit and the ductile fracture toughness limit, determine the reference fracture toughness limit of the core shell; when the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, acquire the comparison result between the second stress intensity factor and the reference fracture toughness limit, and update the test temperature value within the preset temperature range at a preset temperature interval and according to the comparison result. The preset temperature interval is the absolute value of the difference between the two test temperature values ​​before and after the update. For example, the preset temperature interval can be 1℃, 2℃, or others.

[0093] In one embodiment, updating the test temperature value within a preset temperature range at preset temperature intervals and according to the magnitude comparison result includes: when the magnitude comparison result indicates that the second stress intensity factor is greater than the reference fracture toughness limit, updating the test temperature value within the preset temperature range at preset temperature intervals along the direction of increasing test temperature value; when the magnitude comparison result indicates that the second stress intensity factor is less than the reference fracture toughness limit, updating the test temperature value within the preset temperature range at preset temperature intervals along the direction of decreasing test temperature value.

[0094] In one embodiment, the step of determining the brittle fracture toughness limit and the ductile fracture toughness limit of the core shell based on the material type and test temperature value of the core shell includes: determining the brittle fracture toughness limit of the core shell based on the test temperature value and the irradiation embrittlement transformation reference temperature value of the core shell; the irradiation embrittlement transformation reference temperature value is determined based on the neutron flux of the reactor, the mass proportion of the first type of material in the material type of the core shell, and the mass proportion of the second type of material in the material type; and determining the ductile fracture toughness limit of the core shell based on the test temperature value and the mass proportion of the third type of material in the material type.

[0095] The irradiation embrittlement transition reference temperature is the reference temperature at which the core material, under neutron irradiation, transitions from ductile fracture to brittle fracture. The irradiation embrittlement transition reference temperature value is the specific value of the irradiation embrittlement transition reference temperature. Neutron fluence is a physical quantity describing the properties of the neutron radiation field using the number of incident neutrons. The mass percentage of a certain type of material is the ratio of the mass of that type of material to the total mass of the core material.

[0096] In this embodiment, the brittle fracture toughness limit is determined based on the test temperature value and the irradiation embrittlement transformation reference temperature value of the core tube. The ductile fracture toughness limit of the core tube is determined based on the test temperature value and the mass proportion of the third type of material in the material type. Thus, the reference fracture toughness limit can be determined. Combined with subsequent steps, the ultimate defect depth value can be determined, creating conditions for saving nuclear power unit resources.

[0097] In one embodiment, the computer device can determine the brittle fracture toughness limit of the core tube according to the following formula (5) based on the test temperature value and the irradiation embrittlement transformation reference temperature value of the core tube.

[0098]

[0099] Among them, K IC It can characterize the brittle fracture toughness limit. The physical unit of the brittle fracture toughness limit is . (Megapascals multiplied by the square root of meters). T represents the test temperature and is used to substitute into the test temperature value. RT NDTIt can characterize the irradiation embrittlement transition reference temperature and is used to substitute into the irradiation embrittlement transition reference temperature value. T-RT NDT It can characterize the difference between the test temperature and the irradiation embrittlement transition reference temperature. e can characterize the natural constant. Characterized by 0.036(T-RT) of e NDT The brittle fracture toughness limit can be calculated by substituting the test temperature value and the irradiation embrittlement transformation reference temperature value into (+55.5). The smaller of the calculated result and 220.

[0100] In one embodiment, the computer equipment can determine the irradiation embrittlement conversion reference temperature value based on the initial value and the change value of the irradiation embrittlement conversion reference temperature, and determine the change value of the irradiation embrittlement conversion reference temperature according to the following formula (6) based on the neutron flux of the reactor, the mass proportion of the first type of material in the core shell material type, and the mass proportion of the second type of material in the material type. Wherein, the initial value of the irradiation embrittlement conversion reference temperature is a pre-set initial value of the irradiation embrittlement conversion reference temperature, for example, -20℃. The change value of the irradiation embrittlement conversion reference temperature is the change value of the material's irradiation embrittlement conversion reference temperature caused by neutron irradiation. The first type can be copper. The second type can be phosphorus.

[0101] ΔRT NDT =[22+556×(%Cu-0.08)+2778×(%P-0.008)]×(F / 10 19 ) 0.5 Formula (6)

[0102] Where, ΔRT NDT It can characterize the change in the reference temperature for irradiation embrittlement transformation. %Cu characterizes the mass percentage of copper in the material. %P characterizes the mass percentage of phosphorus in the material. F characterizes the neutron fluence, with the physical unit of neutron fluence being n / cm². 2 (Neutrons per square centimeter)

[0103] In one embodiment, the computer device can acquire a ductile fracture toughness limit table that records the correspondence between temperature range, material content range, and preset ductile fracture toughness limit values. Based on the ductile fracture toughness limit table, the device can determine the target temperature range to which the test temperature value belongs, determine the mass percentage of the third type of material in the core shell material type, determine the target material content range to which the mass percentage of the third type of material belongs based on the ductile fracture toughness limit table, and use the preset ductile fracture toughness limit value corresponding to the target temperature range and the target material content range as the ductile fracture toughness limit value.

[0104] In one embodiment, the computer equipment can determine the ductile fracture toughness limit of the reactor core shell based on the test temperature value and the mass proportion of the third type of material in the material type, according to Table 1 below. The third type can be sulfur.

[0105] Table 1. Limits of ductility and fracture toughness for materials

[0106]

[0107] Among them, K JC It can characterize the limit of ductile fracture toughness, and the physical unit is . The sulfur content of the base material characterizes the proportion of sulfur material in the total mass of the base material. When the test temperature is not less than 200℃ or not greater than 50℃, the corresponding preset ductile fracture toughness limit can be determined according to the sulfur material content in the core shell's base material. For example, when the test temperature is 30℃ and the sulfur material content is 0.008, the preset ductile fracture toughness limit is the limit corresponding to T≤50℃ and 0.005<S≤0.008, which is 205. When the test temperature is less than 200℃ and greater than 50℃, based on Table 1, the preset ductile fracture toughness limit corresponding to each material content range between less than 200℃ and greater than 50℃ can be determined by interpolation. For example, the temperature range of 50℃ to 200℃ can be divided into three temperature ranges: 50℃ to 100℃, 100℃ to 150℃, and 150℃ to 200℃. In the material content range of S≤0.005, the preset ductile fracture toughness limit value corresponding to T≤50℃ is 245, and the preset ductile fracture toughness limit value corresponding to T≥200℃ is 200. Therefore, by using interpolation, in the material content range of S≤0.005, the preset ductile fracture toughness limit value corresponding to T for 50℃ to 100℃ can be 233.75, the preset ductile fracture toughness limit value corresponding to T for 100℃ to 150℃ can be 222.5, and the preset ductile fracture toughness limit value corresponding to T for 150℃ to 200℃ can be 211.25.

[0108] In one embodiment, the computer equipment can determine a reference fracture toughness limit based on the brittle fracture toughness limit and the ductile fracture toughness limit, according to the limit determination method specified in the evaluation criteria of the RSE-M (In-Service Inspection Rules for Mechanical Components of Nuclear Island in Pressurized Water Reactor Nuclear Power Plants) 1997 version + 2000 Addendum. Specifically, the computer equipment can determine a first ratio of the brittle fracture toughness limit to a first preset value and a second ratio of the ductile fracture toughness limit to a second preset value, and determine the smaller of the first ratio and the second ratio as the reference fracture toughness limit. The first ratio is the ratio of the brittle fracture toughness limit to the first preset value; the second ratio is the ratio of the ductile fracture toughness limit to the second preset value. The first preset value can be 1.3, and the second preset value can be 1.15.

[0109] Table 2 Evaluation Criteria in RSE-M 1997 Version + 2000 Addendum

[0110]

[0111] Among them, K cp It can characterize the second stress intensity factor. This can characterize the first ratio of the brittle fracture toughness limit to a first preset value of 1.3. The second ratio, which can characterize the ductile fracture toughness limit value, to the second preset value, It can represent the smaller of the first ratio and the second ratio.

[0112] In one embodiment, in a specific application scenario, the defect detection steps for the core cylinder in the reactor pressure vessel are as follows.

[0113] The computer equipment can obtain a preset defect depth value, determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor, determine the initial thickness value of the cylinder wall where the defect is located, determine the difference between the initial thickness value and the defect depth value as the remaining thickness value, determine the tip depth value and the tip stress value of each of the multiple tip points on the expansion path of the defect, and perform polynomial fitting based on the remaining thickness value, the tip depth value of each of the multiple tip points, the tip stress value of each of the multiple tip points and the following formula (1) to perform polynomial fitting on the stress distribution on the structural wall thickness at the location of the defect, and obtain the stress fitting coefficient.

[0114] The computer equipment can determine the preset shape influence coefficient according to the influence function of the elliptical crack at the core cylinder in the RCC-M specification, and determine the third stress intensity factor according to formula (2) based on the defect depth value, the remaining thickness value, the preset shape influence coefficient and the stress fitting coefficient.

[0115] The computer equipment can determine the first stress intensity factor of the defect based on the third stress intensity factor and the pre-configured pressure value, according to the following formula (3). Wherein, the pre-configured pressure value is 1.2 times the design pressure value of the pressure vessel.

[0116] The computer equipment can obtain the yield strength of the core cylinder material, determine the radius value of the plastic zone at the tip of the defect based on the yield strength of the material and the first stress intensity factor; determine the first reference value and the second reference value based on the defect depth value, determine the correction coefficient based on the numerical comparison results of the radius value with the first reference value and the second reference value respectively; and determine the second stress intensity factor according to formula (4) based on the radius value, the correction coefficient, the defect depth value and the first stress intensity factor.

[0117] The computer equipment can obtain the mass percentage of copper and phosphorus materials in the reactor core, as well as the neutron flux of the reactor. It then determines the change value of the irradiation embrittlement transition reference temperature according to formula (6), obtains the initial value of the irradiation embrittlement transition reference temperature, and sums the change value of the irradiation embrittlement transition reference temperature with the initial value to obtain the irradiation embrittlement transition reference temperature. It also obtains the test temperature value during the primary circuit hydrostatic test, and determines the brittle fracture toughness limit according to formula (5) based on the test temperature value and the irradiation embrittlement transition reference temperature value. The test temperature value can be related to the irradiation embrittlement transition reference temperature value; for example, the difference between the test temperature value and the irradiation embrittlement transition reference temperature value is 30℃.

[0118] The computer equipment can obtain the mass ratio of sulfur material in the core shell parent material. Based on the mass ratio of sulfur material and the test temperature, the ductile fracture toughness limit is determined according to Table 1. Based on the brittle fracture toughness limit and the ductile fracture toughness limit, the reference fracture toughness limit is determined according to Table 2.

[0119] When the second stress intensity factor is not equal to the reference fracture toughness limit, the computer equipment can obtain the comparison result between the second stress intensity factor and the reference fracture toughness limit, update the defect depth value according to the comparison result within the depth value range, and repeat the above steps of determining the difference between the initial thickness value and the defect depth value as the remaining thickness value until the second stress intensity factor is equal to the reference fracture toughness limit. The defect depth value when the second stress intensity factor is equal to the reference fracture toughness limit is determined as the limit defect depth value that can be detected by the primary hydrostatic test.

[0120] In a specific scenario, the reactor could be a CRP1000 nuclear power unit. Based on the RSE-M standard, with a pre-configured pressure value of 1.2 times the design pressure value and a test temperature value that differs from the irradiation embrittlement conversion reference temperature value by 30°C, following the aforementioned defect detection steps for the reactor core cylinder in the reactor pressure vessel, the limit defect depth value for critical instability propagation of the reactor core cylinder at the end of its service life can be calculated to be greater than 48 mm. This can be understood as the limit defect depth value being approximately 48 mm. When there are defects in the core cylinder with a defect depth value exceeding 48 mm, performing a primary circuit hydrostatic test on the pressure vessel will lead to instability and rupture of the pressure vessel.

[0121] The aforementioned defect detection method for the reactor core cylinder in the reactor pressure vessel is based on inverse calculation of defect depth using linear elasticity mechanics to obtain the limiting defect size for the primary circuit hydrostatic test. Specifically, see... Figure 2The simplified flowchart illustrating the primary circuit hydrostatic test detection capability assessment first analyzes the characteristics of primary circuit hydrostatic testing under standard specifications. For example, referring to the RSE-M specification B2140, "Technical Conditions for Periodic Hydrostatic Testing," the primary circuit hydrostatic test assesses the minimum permissible pressure and temperature values ​​under the premise of a preset reactor pressure vessel shell defect depth of 20 mm. Therefore, it can be seen that the ultimate defect depth value can be calculated in reverse under the preset pressure and temperature values. Furthermore, based on linear elasticity, the ultimate defect depth value is calculated according to the aforementioned defect detection method for the reactor core shell in the reactor pressure vessel. By then applying the ultimate defect depth value to a specific reactor model, a quantitative assessment of the primary circuit hydrostatic test detection capability can be achieved. Referring to the experimental verification of customized defective containers abroad, the reliability of the limit defect depth value calculated in reverse based on linear elasticity can be indirectly verified. Specifically, relevant foreign technical institutions have carried out destructive tests on pressure vessels. The testers manufactured a series of medium-sized pressure vessels and conducted brittle-ductile failure tests on the vessels using hydraulic and pneumatic pressure under certain temperature ranges, given defect size and stress levels. The results showed that the fracture pressure predicted based on linear elastic fracture mechanics was close to the experimental value. Therefore, the above-mentioned defect detection method for the reactor core cylinder in reactor pressure vessels based on linear elasticity has a certain degree of reliability.

[0122] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0123] Based on the same inventive concept, this application also provides a device for detecting defects in the core cylinder of a reactor pressure vessel, used to implement the defect detection method for the core cylinder of a reactor pressure vessel as described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the device for detecting defects in the core cylinder of a reactor pressure vessel provided below can be found in the limitations of the defect detection method for the core cylinder of a reactor pressure vessel described above, and will not be repeated here.

[0124] In one embodiment, such as Figure 3 As shown, a defect detection device 300 for the core shell of a reactor pressure vessel is provided, comprising: a defect depth management module 310, a stress intensity factor management module 320, and a fracture toughness limit management module 330, wherein:

[0125] The defect depth management module 310 is used to obtain a preset defect depth value and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor.

[0126] The stress intensity factor management module 320 is used to determine the first stress intensity factor of a defect based on the defect depth value and the pre-configured pressure value; the pre-configured pressure value characterizes the pressure when the reactor undergoes a primary loop hydrostatic test; obtain the material yield strength of the core shell; and perform plastic correction on the first stress intensity factor according to the material yield strength and the defect depth value to obtain the second stress intensity factor.

[0127] The fracture toughness limit management module 330 is used to determine the reference fracture toughness limit of the core tube. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core tube. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core tube and the test temperature value during the primary circuit hydrostatic test.

[0128] The defect depth management module 310 is also used to update the defect depth value according to the second stress intensity factor and the reference fracture toughness limit when the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, and to perform the step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value until the second stress intensity factor and the reference fracture toughness limit meet the preset matching relationship, so as to obtain the limit defect depth value that can be detected by the primary hydrostatic test.

[0129] In one embodiment, the stress intensity factor management module 320 is further configured to obtain the initial thickness value of the cylinder wall where the defect is located in the core cylinder; determine the remaining thickness value of the cylinder wall based on the initial thickness value and the defect depth value; determine the third stress intensity factor of the defect under unit pressure based on the defect depth value and the remaining thickness value; and determine the first stress intensity factor of the defect based on the third stress intensity factor and the pre-configured pressure value.

[0130] In one embodiment, the stress intensity factor management module 320 is further used to obtain a preset shape influence coefficient and a stress fitting coefficient. The stress fitting coefficient is determined based on the tip depth value and the tip stress value of each of the multiple tip points on the expansion path of the defect. Based on the defect depth value, the remaining thickness value, the preset shape influence coefficient, and the stress fitting coefficient, a third stress intensity factor of the defect under unit pressure is determined. The third stress intensity factor is positively correlated with the preset shape influence coefficient and the stress fitting coefficient.

[0131] In one embodiment, the stress intensity factor management module 320 is further configured to determine the radius value of the plastic zone at the tip of the defect based on the material yield strength and the first stress intensity factor; the radius value and the ratio between the first stress intensity factor and the material yield strength are positively correlated; a correction coefficient is determined based on the numerical comparison results of the radius value with the first reference value and the second reference value; the first reference value and the second reference value are determined based on the defect depth value, and the second reference value is greater than the first reference value; and the first stress intensity factor is plastically corrected based on the radius value, the correction coefficient, and the defect depth value to obtain the second stress intensity factor.

[0132] In one embodiment, the fracture toughness limit management module 330 is further configured to acquire a preset test temperature value and use the preset test temperature value as the test temperature value for conducting a primary circuit hydrostatic test; determine the brittle fracture toughness limit and ductile fracture toughness limit of the core cylinder based on the material type of the core cylinder and the test temperature value, and determine a reference fracture toughness limit of the core cylinder based on the brittle fracture toughness limit and the ductile fracture toughness limit; when the second stress intensity factor does not conform to the preset matching relationship with the reference fracture toughness limit, update the test temperature value within the preset temperature range according to the second stress intensity factor and the reference fracture toughness limit, and execute the step of determining the brittle fracture toughness limit and ductile fracture toughness limit of the core cylinder based on the material type of the core cylinder and the test temperature value; the defect depth management module 310 is further configured to, when the test temperature value has been updated within the preset temperature range and there is no reference fracture toughness limit that conforms to the preset matching relationship with the second stress intensity factor, trigger the step of updating the defect depth value according to the second stress intensity factor and the reference fracture toughness limit.

[0133] In one embodiment, the fracture toughness limit management module 330 is further configured to determine the brittle fracture toughness limit of the core tube based on the test temperature value and the irradiation embrittlement conversion reference temperature value of the core tube; the irradiation embrittlement conversion reference temperature value is determined based on the neutron flux of the reactor, the mass percentage of the first type of material in the material type of the core tube, and the mass percentage of the second type of material in the material type; and the ductile fracture toughness limit of the core tube is determined based on the test temperature value and the mass percentage of the third type of material in the material type.

[0134] The various modules in the defect detection device for the reactor core cylinder in the aforementioned reactor pressure vessel can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0135] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 4 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for detecting defects in the core shell of a reactor pressure vessel. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0136] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0137] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0138] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0139] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0140] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0141] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0142] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for detecting defects in the core shell of a reactor pressure vessel, characterized in that, The method includes: Obtain a preset defect depth value, and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor; Based on the defect depth value and the pre-configured pressure value, a first stress intensity factor for the defect is determined; the pre-configured pressure value characterizes the pressure during the primary loop hydrostatic test of the reactor. The yield strength of the core cylinder material is obtained, and the first stress intensity factor is plastically corrected based on the yield strength and the defect depth value to obtain the second stress intensity factor. A reference fracture toughness limit is determined for the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed. When the second stress intensity factor does not meet the preset matching relationship with the reference fracture toughness limit, the defect depth value is updated according to the second stress intensity factor and the reference fracture toughness limit. The step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value is performed until the second stress intensity factor meets the preset matching relationship with the reference fracture toughness limit, and the limit defect depth value that can be detected by the first-loop hydrostatic test is obtained.

2. The method according to claim 1, characterized in that, The step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value includes: Obtain the initial thickness value of the cylinder wall where the defect is located in the core cylinder; The remaining thickness of the cylinder wall is determined based on the initial thickness value and the defect depth value. Based on the defect depth value and the remaining thickness value, the third stress intensity factor of the defect under unit pressure is determined; The first stress intensity factor of the defect is determined based on the third stress intensity factor and the pre-configured pressure value.

3. The method according to claim 2, characterized in that, The step of determining the third stress intensity factor of the defect under unit pressure based on the defect depth value and the remaining thickness value includes: Obtain a preset shape influence coefficient and a stress fitting coefficient, wherein the stress fitting coefficient is determined based on the tip depth value and the tip stress value of each of the multiple tip points on the expansion path of the defect; Based on the defect depth value, the remaining thickness value, the preset shape influence coefficient, and the stress fitting coefficient, the third stress intensity factor of the defect under unit pressure is determined; the third stress intensity factor is positively correlated with the preset shape influence coefficient and the stress fitting coefficient.

4. The method according to claim 1, characterized in that, The step of plastically correcting the first stress intensity factor based on the material yield strength and the defect depth value to obtain the second stress intensity factor includes: The radius of the plastic zone at the tip of the defect is determined based on the material's yield strength and the first stress intensity factor; the radius and the ratio of the first stress intensity factor to the material's yield strength are positively correlated. Based on the comparison results of the radius value with the first reference value and the second reference value, a correction coefficient is determined; the first reference value and the second reference value are determined according to the defect depth value, and the second reference value is greater than the first reference value; The first stress intensity factor is plastically corrected based on the radius value, the correction coefficient, and the defect depth value to obtain the second stress intensity factor.

5. The method according to any one of claims 1 to 4, characterized in that, Determining the reference fracture toughness limit of the core cylinder includes: Obtain a preset test temperature value and use the preset test temperature value as the test temperature value when performing the first-loop water pressure test. Based on the material type of the core cylinder and the test temperature value, determine the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder, and based on the brittle fracture toughness limit and the ductile fracture toughness limit, determine the reference fracture toughness limit of the core cylinder. The method further includes: When the second stress intensity factor does not match the reference fracture toughness limit with the preset matching relationship, the test temperature value is updated within the preset temperature range according to the second stress intensity factor and the reference fracture toughness limit, and the step of determining the brittle fracture toughness limit and ductile fracture toughness limit of the core cylinder based on the material type of the core cylinder and the test temperature value is executed. Once the test temperature value has been updated within the preset temperature range, and there is no reference fracture toughness limit that matches the preset matching relationship with the second stress intensity factor, then the step of updating the defect depth value according to the second stress intensity factor and the reference fracture toughness limit is triggered.

6. The method according to claim 5, characterized in that, The determination of the brittle fracture toughness limit and ductile fracture toughness limit of the core cylinder based on the material type of the core cylinder and the test temperature value includes: Based on the test temperature value and the irradiation embrittlement transformation reference temperature value of the core cylinder, the brittle fracture toughness limit of the core cylinder is determined; the irradiation embrittlement transformation reference temperature value is determined according to the neutron flux of the reactor, the mass proportion of the first type of material in the material type of the core cylinder, and the mass proportion of the second type of material in the material type. The ductile fracture toughness limit of the reactor core cylinder is determined based on the test temperature value and the mass proportion of the third type of material in the material type.

7. A defect detection device for the core shell of a reactor pressure vessel, characterized in that, The device includes: The defect depth management module is used to obtain a preset defect depth value and determine the preset defect depth value as the defect depth value of the core cylinder in the pressure vessel of the reactor. The stress intensity factor management module is used to determine the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value; the pre-configured pressure value represents the pressure when the reactor undergoes a primary loop hydrostatic test; the module obtains the material yield strength of the core shell, and performs plastic correction on the first stress intensity factor according to the material yield strength and the defect depth value to obtain the second stress intensity factor; The fracture toughness limit management module is used to determine the reference fracture toughness limit of the core cylinder. The reference fracture toughness limit is determined based on the brittle fracture toughness limit and the ductile fracture toughness limit of the core cylinder. The brittle fracture toughness limit and the ductile fracture toughness limit are respectively related to the material type of the core cylinder and the test temperature value when the primary circuit hydrostatic test is performed. The defect depth management module is further configured to update the defect depth value according to the second stress intensity factor and the reference fracture toughness limit when the second stress intensity factor and the reference fracture toughness limit do not meet the preset matching relationship, and execute the step of determining the first stress intensity factor of the defect based on the defect depth value and the pre-configured pressure value, until the second stress intensity factor and the reference fracture toughness limit meet the preset matching relationship, thereby obtaining the limit defect depth value that can be detected by the primary hydrostatic test.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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