A composite anticorrosion monitoring material for a nuclear power containment displacement system and a preparation method thereof

Abstract

The application belongs to the technical field of nuclear power plants, and particularly relates to a composite anticorrosion monitoring material for a nuclear power containment vessel displacement system and a preparation method. The anticorrosion wire material provided by the application comprises a base material, a first anticorrosion coating layer arranged on the surface of the base material, and a second anticorrosion coating layer arranged on the surface of the first anticorrosion coating layer. The base material is an iron-nickel alloy, and the mass content of nickel in the iron-nickel alloy is 28.5-30%. The first anticorrosion coating layer is a zinc layer. The second anticorrosion coating layer is an anticorrosion paint layer. The anticorrosion wire material provided by the application has excellent anticorrosion performance as a straight section monitoring wire material, and has a small linear expansion coefficient in different temperature ranges, thereby significantly improving the accuracy of nuclear power plant containment vessel displacement measurement. The application provides a nuclear power plant containment vessel vertical displacement monitoring method, and solves the engineering problem of frequent corrosion and fracture of monitoring wire materials in nuclear power plants in the southern coastal region.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power plant technology, specifically relating to a composite anti-corrosion monitoring material for nuclear power containment displacement systems and its preparation method. Background Technology

[0002] The containment vessel is one of the most important structures in a nuclear power plant, and its main function is to prevent the leakage of radioactive materials into the environment. To ensure the structural integrity and stability of the containment vessel under extreme conditions, regular overall testing and daily monitoring should be conducted in accordance with relevant domestic and international standards. The aim is to evaluate the performance of the containment vessel under external pressure or impact, covering multiple dimensions such as strain, temperature, displacement, prestress, and appearance.

[0003] Nuclear power plant containment displacement monitoring primarily employs a containment displacement monitoring system, which is divided into horizontal and vertical displacement monitoring. Both rely on monitoring wires to collect data via displacement transfer methods. The selection of the monitoring wire is crucial; it must meet certain tensile strength requirements to withstand external forces that may be encountered during monitoring (such as the tension generated by a suspended weight) and prevent breakage. Furthermore, the vertical displacement monitoring wire must also have a low coefficient of thermal expansion to reduce the interference of temperature changes on the monitoring results and ensure data accuracy.

[0004] Currently, the containment displacement monitoring wires used in nuclear power plants are mainly made of stainless steel or alloy wires. Stainless steel wires, due to their high coefficient of linear expansion, cannot be directly used for vertical containment displacement monitoring. Alloy wires, however, lack sufficient corrosion resistance in harsh environments such as those in southern coastal regions, making them prone to corrosion and breakage. Once the monitoring wire breaks, the data collected by the displacement transfer method will be interrupted, affecting data continuity and negatively impacting subsequent displacement monitoring and life extension assessments of the nuclear power plant. Frequent breakages also increase the plant's maintenance and repair costs.

[0005] In summary, the existing technologies for monitoring containment displacement in nuclear power plants have poor expansion coefficients and corrosion resistance, resulting in low accuracy in containingment displacement measurements. Summary of the Invention

[0006] The purpose of this invention is to provide a composite anti-corrosion monitoring material and preparation method for nuclear power plant containment displacement systems. The anti-corrosion wire provided by this invention has excellent anti-corrosion performance as a straight section monitoring wire, and has a small coefficient of linear expansion in different temperature ranges, thereby significantly improving the accuracy of containment displacement measurement in nuclear power plants.

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

[0008] This invention provides an anti-corrosion wire material, comprising a substrate, a first anti-corrosion coating disposed on the surface of the substrate, and a second anti-corrosion coating disposed on the surface of the first anti-corrosion coating; the substrate is an iron-nickel alloy, wherein the mass content of nickel in the iron-nickel alloy is 28.5-30%; the first anti-corrosion coating is a zinc layer; and the second anti-corrosion coating is an anti-corrosion paint layer.

[0009] Preferably, the iron-nickel alloy further includes chromium, and the mass content of chromium is 0.1% to 0.3%.

[0010] Preferably, the anti-corrosion paint layer comprises, from the inside out, a primer layer, a topcoat layer, and a release layer; the primer layer is an epoxy zinc-rich primer, the topcoat layer is a polyurethane topcoat, and the release layer is an anti-corrosion spray paint.

[0011] Preferably, the thickness of the zinc layer is 15–25 μm;

[0012] The zinc layer is prepared by chemical electroplating. The electroplating solution used in the chemical electroplating includes: 100-110 g / L zinc sulfate, 20-25 g / L potassium chloride, 0.15-0.2 g / L sodium dodecyl sulfate, 15-20 g / L disodium EDTA, and 6-8 g / L potassium sodium tartrate. The pH value of the electroplating solution is 4-5. The conditions for the chemical electroplating include: a current density of 2-3 A / dm² and a temperature of 30±1℃.

[0013] This invention provides the application of the corrosion-resistant wire material described above in the detection wire material used in the containment displacement monitoring system of a nuclear power plant.

[0014] This invention provides a detection wire material for a nuclear power plant containment displacement monitoring system, including a straight section monitoring wire material, a module monitoring wire material, and a connection section monitoring wire material; the straight section monitoring wire material is the corrosion-resistant wire material described in the above technical solution.

[0015] Preferably, the monitoring wire at the mold box is a stainless steel wire, and the length of the monitoring wire at the mold box is ≤30cm; the monitoring wire at the connection is a carbon fiber wire, and the length of the monitoring wire at the connection is ≤50cm.

[0016] This invention provides a nuclear power plant containment displacement monitoring system, comprising a module, a monitoring wire, and a counterweight. The two ends of the monitoring wire are respectively connected to the module and the counterweight. The monitoring wire is the detection wire material described in the above technical solution. One end of the monitoring wire at the module is connected to the module, and the other end is connected to one end of the straight section monitoring wire via a first wire fusion connector. The other end of the straight section monitoring wire is connected to one end of the connection point detection wire via a second wire fusion connector, and the other end of the connection point detection wire is connected to the counterweight.

[0017] Preferably, the first or second filament fusion device includes an inner sleeve, an outer protective sleeve, a sealing sleeve, and a locking nut. The inner sleeve is fitted onto the ends where two adjacent filament sections are connected. The outer protective sleeve is fitted onto the inner sleeve. A sealing sleeve is provided at each end of the inner sleeve, and the sealing sleeve is fitted onto the filament. The inner sleeve is sealed to the filament through the sealing sleeve. A locking nut is provided at each end of the outer protective sleeve, and the locking nut is fitted onto the filament. The outer walls at both ends of the outer protective sleeve are provided with external threads, and the locking nut is threadedly connected to both ends of the outer protective sleeve. When the locking nut is rotated and pushed forward, it compresses the sealing sleeve into the inner sleeve, causing radial contraction. The contact friction between the sealing sleeve, the filament, and the inner sleeve locks the filament inside the inner sleeve.

[0018] This invention provides a method for monitoring vertical displacement of the containment vessel in a nuclear power plant, comprising the following steps:

[0019] The total deformation of the detection wire was obtained by using the nuclear power plant containment displacement monitoring system described in the above technical solution.

[0020] The vertical displacement monitoring data of the nuclear power plant containment vessel is obtained based on the initial length of the monitoring wire, the comprehensive linear expansion coefficient of the detection wire, the total deformation, and the environmental temperature difference before and after the monitoring corresponding to the total deformation. The comprehensive linear expansion coefficient of the detection wire is obtained from the length and linear expansion coefficient of the monitoring wire in the straight section, the length and linear expansion coefficient of the monitoring wire at the mold box, and the length and linear expansion coefficient of the monitoring wire at the connection.

[0021] This invention provides an anti-corrosion wire material, comprising a substrate, a first anti-corrosion coating disposed on the surface of the substrate, and a second anti-corrosion coating disposed on the surface of the first anti-corrosion coating; the substrate is an iron-nickel alloy, wherein the nickel content of the iron-nickel alloy is 28.5%–30% by mass; the first anti-corrosion coating is a zinc layer; and the second anti-corrosion coating is an anti-corrosion paint layer. The anti-corrosion wire material provided by this invention uses an iron-nickel alloy as its substrate, and by controlling the mass fraction of the main component, nickel (Ni), between 28.5% and 30.0%, it can impart resistance to neutron radiation swelling, while effectively reducing the coefficient of thermal expansion and improving the corrosion resistance of the anti-corrosion wire material. Furthermore, this invention combines the first and second anti-corrosion coatings to form a dual anti-corrosion system, enabling the anti-corrosion wire material to effectively resist environmental corrosion and block the penetration of radioactive aerosols, thus solving the engineering problem of frequent corrosion and breakage of monitoring wire materials. Therefore, the anti-corrosion wire material provided by this invention has excellent anti-corrosion performance as a linear monitoring wire material, and its coefficient of linear expansion is small within different temperature ranges, thereby significantly improving the accuracy of containment displacement measurement in nuclear power plants. The results of the embodiments show that the anti-corrosion wire material provided by the present invention, when subjected to a linear expansion coefficient test, has a linear expansion coefficient α1 that does not exceed 0.005℃ between 25℃ and 100℃. -1 .

[0022] Furthermore, in this invention, the iron-nickel alloy also includes chromium, with a chromium content of 0.1% to 0.3% by mass. This invention further enhances the material's resistance to radiation embrittlement and improves the corrosion resistance and high-temperature performance of the iron-nickel alloy through the use of chromium (Cr).

[0023] This invention provides a detection wire for a nuclear power plant containment displacement monitoring system, comprising a straight section monitoring wire, a module section monitoring wire, and a connection section monitoring wire; the straight section monitoring wire is the corrosion-resistant wire described in the aforementioned technical solution. This invention provides a three-section detection wire, with the main testing section (straight section) using corrosion-resistant wire, which significantly improves the corrosion resistance of the detection wire, reduces the coefficient of linear expansion within different temperature ranges, solves the engineering problem of frequent corrosion and breakage of the monitoring wire, and significantly improves the accuracy of containment displacement measurement in nuclear power plants.

[0024] Furthermore, in this invention, the monitoring wire at the mold box is made of stainless steel wire, and its length is ≤30cm; the monitoring wire at the connection point is made of carbon fiber wire, and its length is ≤50cm. In this invention, using stainless steel wire as the monitoring wire at the mold box ensures the corrosion resistance of the mold box area; simultaneously, the ≤30cm length design of the monitoring wire at the mold box reduces deformation caused by temperature changes, improving measurement accuracy; in this invention, using carbon fiber wire as the connection point monitoring wire, carbon fiber wire possesses the characteristics of being lightweight, high-strength, low-expansion, and corrosion-resistant, reducing the overall weight of the monitoring system, ensuring the continuity and integrity of monitoring data, and its ≤50cm length also improves the reading accuracy of the displacement monitoring equipment.

[0025] This invention provides a nuclear power plant containment displacement monitoring system, comprising a module, monitoring wire, and a counterweight. The two ends of the monitoring wire are connected to the module and the counterweight, respectively. The monitoring wire is the detection wire material described in the previous technical solution. One end of the monitoring wire at the module is connected to the module, and the other end is connected to one end of a straight section of the monitoring wire via a first wire fusion connector. The other end of the straight section of the monitoring wire is connected to one end of the connection section of the detection wire via a second wire fusion connector. The other end of the connection section of the detection wire is connected to the counterweight. The nuclear power plant containment displacement monitoring system provided by this invention provides strong support for the stability assessment of nuclear power plant structures; it effectively extends the service life of the monitoring wire in high temperature, high humidity, and high radiation environments, and solves the engineering problem of frequent corrosion and breakage of monitoring wires in nuclear power plants in southern coastal areas.

[0026] Furthermore, in this invention, the first or second wire fusion device includes an inner sleeve, an outer protective sleeve, a sealing sleeve, and a locking nut. The inner sleeve is fitted onto the ends where two adjacent wire segments are connected. The outer protective sleeve is fitted over the inner sleeve. A sealing sleeve is provided at each end of the inner sleeve, and the sealing sleeve is fitted onto the wire. The inner sleeve is sealed to the wire through the sealing sleeve. A locking nut is provided at each end of the outer protective sleeve, and the locking nut is fitted onto the wire and threadedly connected to the outer protective sleeve to lock the wire within the inner sleeve. This invention uses a first and second wire fusion device to connect the detection wires, utilizing a reliable mechanical structure to achieve a secure connection of the three detection wire segments. Simultaneously, it ensures that the monitoring wires are concentric and coaxial, effectively avoiding data interruption and ensuring the continuity and accuracy of the monitoring data.

[0027] This invention provides a method for monitoring vertical displacement of the containment structure in a nuclear power plant, comprising the following steps: using the nuclear power plant containment displacement monitoring system described in the above technical solution to obtain the total deformation of the detection wire; obtaining vertical displacement monitoring data of the nuclear power plant containment structure based on the initial length of the detection wire, the comprehensive linear expansion coefficient of the detection wire, the total deformation, and the corresponding environmental temperature difference before and after monitoring; the comprehensive linear expansion coefficient of the detection wire is obtained from the length and linear expansion coefficient of the straight segment of the detection wire, the length and linear expansion coefficient of the detection wire at the mold section, and the length and linear expansion coefficient of the detection wire at the connection section. This invention improves the accuracy of nuclear power plant containment displacement measurement by correcting the comprehensive test linear expansion coefficient α, providing strong support for the stability assessment of nuclear power plant structures; it also effectively extends the service life of the monitoring wire in high temperature, high humidity, and high radiation environments, solving the engineering problem of frequent corrosion and breakage of monitoring wires in nuclear power plants in southern coastal areas. Attached Figure Description

[0028] Figure 1 A flowchart illustrating a method for monitoring vertical displacement of a nuclear power plant containment structure provided by this invention;

[0029] Figure 2 This invention provides a structural schematic diagram of a nuclear power plant containment displacement monitoring system.

[0030] Figure 3 A schematic diagram of the wire fusion device structure for monitoring;

[0031] In the diagram: 1 is the monitoring wire at the mold box, 2 is the monitoring wire at the straight section, 3 is the monitoring wire at the connection, 4 is the wire fusion device, 41 is the locking nut, 42 is the sealing sleeve, 43 is the internal sleeve, and 44 is the protective sleeve. Detailed Implementation

[0032] This invention provides an anti-corrosion wire material, comprising a substrate, a first anti-corrosion coating disposed on the surface of the substrate, and a second anti-corrosion coating disposed on the surface of the first anti-corrosion coating; the substrate is an iron-nickel alloy, wherein the mass content of nickel in the iron-nickel alloy is 28.5-30%; the first anti-corrosion coating is a zinc layer; and the second anti-corrosion coating is an anti-corrosion paint layer.

[0033] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0034] The anti-corrosion wire material provided by this invention includes a substrate. In this invention, the substrate is an iron-nickel alloy. The mass content of nickel in the iron-nickel alloy is 28.5% to 30%, preferably 29% to 29.5%. In this invention, the iron-nickel alloy preferably also includes chromium, and the mass content of chromium is preferably 0.1% to 0.3%, more preferably 0.2% to 0.25%.

[0035] This invention provides an anti-corrosion filament comprising a first anti-corrosion coating disposed on the surface of a substrate. In this invention, the first anti-corrosion coating is a zinc layer. The thickness of the zinc layer is 15–25 μm, most preferably 20 μm. The zinc layer is preferably prepared by a chemical electroplating method. In this invention, the electroplating solution used for chemical electroplating preferably includes a main salt, a conductive agent, a grain refiner, and a composite complexing agent. The main salt is preferably an inorganic zinc salt, and in the examples, it can be zinc sulfate. The conductive agent is preferably an alkali metal salt, and in the examples, it can be potassium chloride. The grain refiner is preferably a surfactant, and in the examples, it can be sodium dodecyl sulfate. The composite complexing agent preferably includes an EDTA salt and a tartrate. The EDTA salt is preferably disodium EDTA. The tartrate is preferably sodium potassium tartrate. In this invention, the electroplating solution preferably comprises: 100-110 g / L of main salt, 20-25 g / L of conductive agent, 0.15-0.2 g / L of grain refiner, and 21-28 g / L of composite complexing agent; in the examples, it can be 105 g / L of main salt, 22 g / L of conductive agent, 0.18 g / L of grain refiner, and 25 g / L of composite complexing agent; the mass ratio of EDTA salt to tartrate is preferably (15-20):(6-8), and in the examples, it can be 18:7. In this invention, the composite complexing agent preferably comprises 15-20 g / L of disodium EDTA and 6-8 g / L of potassium sodium tartrate; in the examples, it can be 18 g / L of disodium EDTA and 7 g / L of potassium sodium tartrate. The pH value of the electroplating solution is preferably 4-5, and in the examples, it can be 4.5. The conditions for the chemical electroplating preferably include: a current density of 2-3 A / dm³. 2 In the embodiment, it can be 2.6A / dm 2 The preferred temperature for the chemical electroplating is 30±1℃. The chemical electroplating process is preferably carried out using intermittent stirring, specifically stirring for 20 seconds followed by a 15-second pause.

[0036] This invention preferably employs a chemical electroplating method, while simultaneously controlling the composition and operating parameters of the electroplating solution. The resulting zinc coating exhibits uniformity, density, and excellent adhesion. SEM testing of the zinc coating shows a microporosity of ≤3 cells / cm². 2 The grain size of the zinc layer is 4-6 μm, which can significantly improve the corrosion resistance of the anti-corrosion wire.

[0037] The anti-corrosion wire material provided by this invention includes a second anti-corrosion coating disposed on the surface of the first anti-corrosion coating. In this invention, the second anti-corrosion coating is an anti-corrosion paint layer. The anti-corrosion paint layer preferably includes a primer layer, a topcoat layer, and a release layer from the inside out. The primer layer preferably contacts the first anti-corrosion coating. The primer layer is preferably an epoxy zinc-rich primer. The topcoat layer is preferably a polyurethane topcoat. The release layer is preferably an anti-corrosion spray paint. This invention employs a three-layer structure for the second anti-corrosion coating. First, the epoxy zinc-rich primer provides excellent adhesion and rust prevention; then, the polyurethane topcoat enhances weather resistance and abrasion resistance; finally, the anti-corrosion spray paint forms a protective barrier, thereby further improving the overall anti-corrosion effect of the anti-corrosion wire material. This invention does not have special requirements for the types of epoxy zinc-rich primer, polyurethane topcoat, and anti-corrosion spray paint; commercially available products can be used. In this invention, the preparation method of the second anti-corrosion coating preferably includes: sequentially spraying a primer, a topcoat, and an anti-corrosion spray paint onto the surface of the first anti-corrosion coating to obtain the second anti-corrosion coating. The preferred interval between each application of the primer, topcoat, and anti-corrosion spray paint is ≥7 days.

[0038] This invention provides the application of the corrosion-resistant wire material described above in the detection wire material used in the containment displacement monitoring system of a nuclear power plant.

[0039] This invention provides a detection wire material for a nuclear power plant containment displacement monitoring system, including a straight section monitoring wire material, a module monitoring wire material, and a connection section monitoring wire material; the straight section monitoring wire material is the corrosion-resistant wire material described in the above technical solution.

[0040] The detection wire used in the nuclear power plant containment displacement monitoring system provided by this invention includes a straight section monitoring wire. The straight section monitoring wire is the corrosion-resistant wire described in the above technical solution.

[0041] In this invention, the formula for calculating the linear expansion coefficient α1 of the straight segment monitoring wire is as shown in Formula 1:

[0042]

[0043] In formula 1:

[0044] α1 — The linear expansion coefficient of the wire material monitored in a straight line segment, expressed in degrees Celsius (°C). -1 );

[0045] L 11 — Monitoring wire temperature T on a straight section 11 The length of the sample is given below, in millimeters (mm).

[0046] L 12 — Monitoring wire temperature T on a straight section 12 The length of the sample is given below, in millimeters (mm).

[0047] L 10 —The length of the original wire sample monitored in a straight line segment, in millimeters (mm);

[0048] T 11 T 12 —Two temperatures selected in the measurement of wire material in the straight section monitoring, in degrees Celsius (°C).

[0049] The detection wire used in the nuclear power plant containment displacement monitoring system provided by this invention includes a detection wire at the mold box. In this invention, the detection wire at the mold box is a section of detection wire connected to the mold box. One end of the detection wire at the mold box is connected to the mold box, and the other end is connected to one end of the straight section of the detection wire through a first wire fusion device.

[0050] In this invention, the monitoring wire at the mold box is preferably stainless steel wire. The stainless steel wire is preferably 304 stainless steel wire. The length of the monitoring wire at the mold box is preferably ≤30cm.

[0051] In this invention, the formula for calculating the linear expansion coefficient α2 of the filament monitored at the mold box is shown in Formula 2:

[0052]

[0053] In formula 2:

[0054] α2 — Coefficient of linear expansion of the filament at the mold location, expressed in degrees Celsius (°C). -1 );

[0055] L 21 —Monitoring wire temperature T at the mold box 21 The length of the sample is given below, in millimeters (mm).

[0056] L 22 —Monitoring wire temperature T at the mold box 22 The length of the sample is given below, in millimeters (mm).

[0057] L 20 —The length of the original wire sample was monitored at the mold box, in millimeters (mm);

[0058] T 21 T 22 —Two temperatures were selected for the measurement of the wire material at the mold box, in degrees Celsius (°C).

[0059] The detection wire used in the nuclear power plant containment displacement monitoring system provided by this invention includes a connection detection wire. In this invention, the connection detection wire is a section of detection wire connected to the counterweight. The other end of the straight section of the detection wire is connected to one end of the connection detection wire via a second wire fusion device, and the other end of the connection detection wire is connected to the counterweight.

[0060] In this invention, the detection filament at the connection point is preferably a carbon fiber filament. The length of the detection filament at the connection point is preferably ≤50cm.

[0061] In this invention, the formula for calculating the linear expansion coefficient α3 of the wire at the connection point is shown in Formula 3:

[0062]

[0063] In formula 3:

[0064] α3 — Coefficient of linear expansion of the filament at the joint, expressed in degrees Celsius (°C). -1 );

[0065] L 31 —Monitoring wire temperature T at the connection point 31 The length of the sample is given below, in millimeters (mm).

[0066] L 32 —Monitoring wire temperature T at the connection point 32 The length of the sample is given below, in millimeters (mm).

[0067] L 30 —Monitor the original length of the wire sample at the connection point, in millimeters (mm);

[0068] T 31 T 32 —Two temperatures were selected for monitoring the wire material at the connection point, in degrees Celsius (°C).

[0069] In this invention, the straight segment monitoring wire, the mold box monitoring wire, and the connection detection wire are preferably connected in pairs by a wire fusion device, and the straight segment monitoring wire is located in the middle of the mold box monitoring wire and the connection detection wire.

[0070] This invention provides a nuclear power plant containment displacement monitoring system, comprising a module, a monitoring wire, and a counterweight. The two ends of the monitoring wire are respectively connected to the module and the counterweight. The monitoring wire is the detection wire material described in the above technical solution. One end of the monitoring wire at the module is connected to the module, and the other end is connected to one end of the straight section monitoring wire via a first wire fusion connector. The other end of the straight section monitoring wire is connected to one end of the connection point detection wire via a second wire fusion connector, and the other end of the connection point detection wire is connected to the counterweight.

[0071] A schematic diagram of the nuclear power plant containment displacement monitoring system provided by this invention is shown below. Figure 2 As shown below, in conjunction with Figure 2 This invention provides a detailed description of the nuclear power plant containment displacement monitoring system. For example... Figure 2 As shown, the nuclear power plant containment displacement monitoring system provided by this invention includes a module. This invention does not impose any special requirements on the specific structure of the module. The nuclear power plant containment displacement monitoring system provided by this invention includes a counterweight, and this invention does not impose any special requirements on the specific structure of the counterweight. The nuclear power plant containment displacement monitoring system provided by this invention includes a monitoring wire, the two ends of which are respectively connected to the module and the counterweight.

[0072] In this invention, the structural schematic diagram of the first filament fusion device or the second filament fusion device is as follows: Figure 3 As shown below, in conjunction with Figure 3 The first or second filament fusion device provided by the present invention will be described in detail below. Figure 3 As shown, the first or second filament fusion device includes an inner sleeve 43, an outer protective sleeve 44, a sealing sleeve 42, and a locking nut 41. The inner sleeve 43 is used to fit over the ends where two adjacent filaments are connected. The outer protective sleeve 44 is used to fit over the inner sleeve 43. A sealing sleeve 42 is provided at each end of the inner sleeve 43. The sealing sleeve 42 is used to fit over the filaments. The inner sleeve 43 is sealed to the filaments through the sealing sleeves 42. A locking nut 41 is provided at each end of the outer protective sleeve 44. The locking nut 41 is used to fit over the filaments. The outer walls at both ends of the outer protective sleeve 44 are provided with external threads. The locking nut 41 is threaded to both ends of the outer protective sleeve 44. When the locking nut 41 is rotated and pushed forward, it compresses the sealing sleeve 42 into the inner sleeve 43, causing radial contraction. The contact friction between the sealing sleeve 42, the filaments, and the inner sleeve 43 locks the filaments inside the inner sleeve 43.

[0073] As one or more embodiments of the present invention, the outer protective sleeve 44 is a fiber sleeve. In the present invention, the outer protective sleeve 44 has excellent anti-rust and high-temperature resistance properties, effectively extending the service life of the monitoring wire and broadening its application range in various complex environments.

[0074] As one or more embodiments of the present invention, the inner sleeve 43 and the sealing sleeve 42 are both made of flexible materials and are compressible.

[0075] As one or more embodiments of the present invention, the sealing sleeve 42 can enter the interior of the inner sleeve 43 under the condition of bottom surface compression.

[0076] As one or more embodiments of the present invention, the outer diameter of the sealing sleeve 42 is slightly smaller than the outer diameter of the inner sleeve 43.

[0077] As one or more embodiments of the present invention, when the locking nut 41 is rotated and pushed forward, it compresses the sealing sleeve 42 into the inner sleeve 43 in whole or in part.

[0078] As one or more embodiments of the present invention, the inner wall of the locking nut 41 is provided with threads.

[0079] This invention, through the structural design of the first or second wire fusion device, ensures that the two monitoring wires can achieve precise concentricity and coaxiality during installation, which not only improves the compactness of the detection wire structure, but also significantly enhances the efficiency and accuracy of signal transmission.

[0080] This invention provides a method for monitoring vertical displacement of the containment vessel in a nuclear power plant, comprising the following steps:

[0081] The total deformation of the detection wire was obtained by using the nuclear power plant containment displacement monitoring system described in the above technical solution.

[0082] The vertical displacement monitoring data of the nuclear power plant containment vessel is obtained based on the initial length of the monitoring wire, the comprehensive linear expansion coefficient of the detection wire, the total deformation, and the environmental temperature difference before and after the monitoring corresponding to the total deformation. The comprehensive linear expansion coefficient of the detection wire is obtained from the length and linear expansion coefficient of the monitoring wire in the straight section, the length and linear expansion coefficient of the monitoring wire at the mold box, and the length and linear expansion coefficient of the monitoring wire at the connection.

[0083] This invention employs the nuclear power plant containment displacement monitoring system described in the above technical solution to obtain the total deformation of the detected wire. This invention does not specify any particular method for implementing the monitoring.

[0084] After obtaining the total deformation, the present invention obtains the vertical displacement monitoring data of the nuclear power plant containment vessel based on the initial length of the monitoring wire, the comprehensive linear expansion coefficient of the detection wire, the total deformation, and the environmental temperature difference before and after the monitoring corresponding to the total deformation. The comprehensive linear expansion coefficient of the detection wire is obtained from the length and linear expansion coefficient of the monitoring wire in the straight section, the length and linear expansion coefficient of the monitoring wire at the mold box, and the length and linear expansion coefficient of the monitoring wire at the connection.

[0085] This invention relates to the installation of measuring points in a nuclear power plant containment displacement measurement system. Based on the location of these measuring points, the length (initial length) L of the monitoring wire is calculated. Based on this length L, the monitoring wires at the mold box (L2), the straight section (L1), and the connection point (L3) are defined, with L = L... 1+ L 2+ L3.

[0086] The present invention obtains the comprehensive linear expansion coefficient α of the detected filament based on the linear length and linear expansion coefficient of the filament monitored at the straight section, the linear length and linear expansion coefficient of the filament monitored at the mold box, and the linear length and linear expansion coefficient of the filament detected at the connection.

[0087] In this invention, for the overall monitored filament, when the temperature changes by ΔT, which is the difference in ambient temperature before and after monitoring corresponding to the total deformation, the change in the overall monitored length by ΔL can be expressed as Formula 4:

[0088] ΔL=αLΔT Formula 4;

[0089] Meanwhile, the changes in wire length ΔL1 at the straight section, ΔL2 at the mold box, and ΔL3 at the connection are expressed as formulas 5, 6, and 7, respectively.

[0090] ΔL1=α1L1ΔT Formula 5; ΔL2=α2L2ΔT Formula 6; ΔL3=α3L3ΔT Formula 7;

[0091] Since the overall change in the length of the monitored filament is equal to the sum of the changes in the length of each individual filament segment, i.e., Formula 8:

[0092] ΔL=ΔL 1+ ΔL 2+ ΔL3 Formula 8;

[0093] Substituting the formula for the length variation of each section of wire into Formula 8, we obtain Formula 9:

[0094] αLΔT=α1L1ΔT+α2L2ΔT+α3L3ΔT Formula 9;

[0095] Since ΔT represents the same temperature change, it can be eliminated to obtain the comprehensive linear expansion coefficient α, as shown in Formula 10:

[0096]

[0097] In Formula 10, α is the comprehensive linear expansion coefficient, L is the initial length of the detection wire, α1 is the linear expansion coefficient of the detection wire in the straight section, L1 is the linear length of the detection wire in the straight section, α2 is the linear expansion coefficient of the detection wire at the mold box, L2 is the linear length of the detection wire at the mold box, α3 is the linear expansion coefficient of the detection wire at the connection point, and L3 is the linear length of the detection wire at the connection point.

[0098] In this invention, the total deformation in vertical displacement monitoring includes deformation caused by temperature changes and deformation caused by loads. This invention considers the effects of these two types of deformations respectively, and uses the comprehensive linear expansion coefficient α to correct the deformation caused by temperature changes, thereby obtaining the true vertical displacement caused by loads, i.e., the vertical displacement monitoring data of the nuclear power plant containment.

[0099] In this invention, the deformation caused by temperature change is preferably obtained by combining the coefficient of linear expansion and the amount of temperature change, and the calculation formula for the deformation caused by temperature change is shown in Formula 11:

[0100] ΔL thermal＝ αLΔT Formula 11;

[0101] In Formula 11: ΔL thermal This represents the amount of deformation caused by temperature changes.

[0102] This invention calculates the deformation caused by the load from the total deformation and the deformation caused by temperature change. Since the total deformation includes both the deformation caused by temperature change and the deformation caused by the load, the deformation caused by the load is obtained by subtracting the deformation caused by temperature change from the total deformation, as shown in Formula 12:

[0103] ΔL load =ΔL total -ΔL thermal =ΔL total -αlΔT Formula 12;

[0104] In Formula 12: ΔL load Let ΔL be the amount of deformation caused by the load. total The total deformation is ΔL. thermal The deformation caused by temperature change is represented by ΔT, which is the difference in ambient temperature before and after monitoring corresponding to the total deformation.

[0105] In Formula 12: ΔL load The deformation caused by the load is the vertical displacement monitoring data of the nuclear power plant containment.

[0106] According to Formula 12, the present invention can obtain the actual vertical displacement ΔL caused by the load.load In this invention, the above-described correction process for monitoring vertical displacement of the nuclear power plant containment assumes that the deformation caused by temperature changes and the deformation caused by loads are linearly additive, and that there are no other unknown sources of deformation.

[0107] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0108] The following embodiments are in accordance with Figure 1 The flowchart shown is used for monitoring vertical displacement of the containment vessel in a nuclear power plant.

[0109] Example 1

[0110] The preparation method of the straight segment monitoring wire in this embodiment includes the following steps:

[0111] In this embodiment, the substrate of the monitoring wire for the straight segment is an iron-nickel alloy wire, wherein the content of nickel (Ni) in the iron-nickel alloy is 28.5% and the content of chromium (Cr) is 0.2%.

[0112] Zinc was deposited onto iron-nickel alloy wire using chemical electroplating to obtain a metallic zinc layer. The electroplating solution formula was: zinc sulfate 105 g / L, potassium chloride 22 g / L, sodium dodecyl sulfate 0.18 g / L, disodium EDTA 18 g / L + potassium sodium tartrate 7 g / L, with a pH of 4.5. The electrochemical parameters for chemical electroplating included a current density of 2.6 A / dm³. 2 At a temperature of 30±1℃, with intermittent stirring (15s pause / 20s rotation), the zinc layer obtained in this embodiment is uniform, dense, and has high adhesion. SEM tests show that the microporosity of the zinc layer is ≤3 cells / cm. 2 The grain size of the zinc layer is 4–6 μm. The thickness of the zinc layer obtained in this embodiment is 20 μm.

[0113] Three layers of anti-corrosion coating are then applied to the surface of the zinc layer: epoxy zinc-rich primer, polyurethane topcoat, and anti-corrosion spray paint. First, the epoxy zinc-rich primer is applied; then the polyurethane topcoat; and finally the anti-corrosion spray paint, forming an anti-corrosion paint layer. Each layer is applied at least 7 days apart.

[0114] In this embodiment, the linear expansion coefficient α1 of the monitored wire in the straight segment is obtained as 0.0042℃ according to Formula 1. -1 .

[0115] In this embodiment, 304 stainless steel wire is used as the monitoring wire at the mold box.

[0116] In this embodiment, the linear expansion coefficient α2 of the monitored filament at the mold box is obtained according to Formula 2 as 0.015℃.-1 .

[0117] In this embodiment, carbon fiber filament is used as the detection filament for the joint.

[0118] In this embodiment, the coefficient of linear expansion α3 of the wire at the connection point is obtained as 0.003℃ according to Formula 3. -1 .

[0119] A containment displacement monitoring system at a nuclear power plant uses a total wire length L of 62m. Current technology uses 304 stainless steel wire for direct monitoring, but the wire's coefficient of linear expansion is 0.015℃. -1 This implementation uses a segmented monitoring method: the monitored wire length L1 at the straight section is 59 meters, the monitored wire length L2 at the mold box is 1.5 meters, the monitored wire length L3 at the connection point is 1.5 meters, and the linear expansion coefficient α1 of the monitored wire at the straight section is 0.0042℃. -1 The coefficient of linear expansion α2 of the wire at the mold location was 0.015℃. -1 The coefficient of linear expansion α3 of the wire at the connection point was 0.003℃. -1 During the containment integrity test, the temperature change between the highest pressure period and the zero pressure period was 25℃, and the total deformation was 4.25mm. Calculate the comprehensive linear expansion coefficient.

[0120] According to Formula 10, the parameters are as follows:

[0121] Total length: L = 62m

[0122] Straight section monitoring wire: L1 = 59m, α1 = 0.0042℃ -1

[0123] Monitoring of the wire material at the mold box: L2 = 1.5m, α2 = 0.015℃ -1 ;

[0124] Monitoring wire at the connection point: L3 = 1.5m, α3 = 0.003℃ -1 ;

[0125] Calculate the composite linear expansion coefficient:

[0126]

[0127] Based on the containment integrity test data, under the condition of a 25°C temperature difference between the highest pressure and zero pressure stages, the total deformation was measured to be 4.25 mm. The actual vertical displacement caused by the load was calculated using Formula 12:

[0128] ΔL load =ΔL total -ΔL thermal =ΔL total-αLΔT=4.25-0.004432×25=4.1392mm.

[0129] The error is calculated as the difference between the total deformation without correction for temperature effects (4.25 mm) and the corrected actual load deformation (4.1392 mm):

[0130] 4.25mm - 4.1392mm = 0.1108mm

[0131] Accuracy improvement percentage: 0.1108 / 4.1392 × 100% = 2.68%

[0132] After adopting the vertical displacement monitoring method for nuclear power plant containment in this embodiment, the monitoring accuracy of vertical displacement of nuclear power plant containment was improved by 2.68%. The improvement in accuracy was more significant in nuclear power bases with large temperature differences, such as in the southern coastal areas, which verifies the effectiveness of the present invention in improving monitoring accuracy.

[0133] As can be seen from the above embodiments, given the cumulative characteristics and long-term superposition effect of nuclear power monitoring data, even a small single monitoring deviation, if accumulated continuously, will significantly amplify the systematic deviation of the overall database, directly affecting the reliability of nuclear power safety assessments. This invention improves the accuracy of containment displacement measurements in nuclear power plants, providing strong support for the stability assessment of nuclear power plant structures; it also effectively extends the service life of monitoring wires in high-temperature, high-humidity, and high-radiation environments, solving the engineering problem of frequent corrosion and breakage of monitoring wires in nuclear power plants in the southern coastal region.

[0134] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A nuclear power plant containment displacement monitoring system comprising a die box, a monitoring wire and a weight, both ends of the monitoring wire are connected to the die box and the weight respectively; characterized in that, The monitoring wire includes straight section monitoring wire, mold box monitoring wire and connection monitoring wire; the straight section monitoring wire is anticorrosion wire, which includes base material, first anticorrosion coating layer arranged on the surface of the base material and second anticorrosion coating layer arranged on the surface of the first anticorrosion coating layer; the base material is iron-nickel alloy, the mass content of nickel element in the iron-nickel alloy is 28.5-30%; the first anticorrosion coating layer is zinc layer; the second anticorrosion coating layer is anticorrosion paint layer; One end of the mold box monitoring wire is connected with the mold box, and the other end is connected with one end of the straight section monitoring wire through the first wire fusion device; the other end of the straight section monitoring wire is connected with one end of the connection monitoring wire through the second wire fusion device; the other end of the connection monitoring wire is connected with the weight.

2. The containment shift monitoring system of claim 1, wherein, The iron-nickel alloy further includes chromium element, and the mass content of the chromium element is 0.1-0.3%.

3. The containment shift monitoring system of claim 1 or 2, wherein, The anticorrosion paint layer includes primer layer, topcoat layer and isolation layer from inside to outside; the primer layer is zinc-rich epoxy primer, the topcoat layer is polyurethane topcoat, and the isolation layer is anticorrosion self-spraying paint.

4. The containment movement monitoring system of a nuclear power plant according to claim 1 or 2, characterized in that, The thickness of the zinc layer is 15-25 μm; The zinc layer is prepared by chemical electroplating method; The electroplating solution used in the chemical electroplating includes 100-110 g / L zinc sulfate, 20-25 g / L potassium chloride, 0.15-0.2 g / L sodium dodecyl sulfate, 15-20 g / L disodium EDTA and 6-8 g / L potassium sodium tartrate; the pH value of the electroplating solution is 4-5; the conditions of the chemical electroplating include current density of 2-3 A / dm2 and temperature of 30±1 ℃.

5. The nuclear power plant containment movement monitoring system in accordance with claim 1, wherein, The mold box monitoring wire is stainless steel wire, and the length of the mold box monitoring wire is ≤30 cm; the connection monitoring wire is carbon fiber wire, and the length of the connection monitoring wire is ≤50 cm.

6. The nuclear power plant containment movement monitoring system in accordance with claim 1, wherein, The first wire fusion device or the second wire fusion device includes internal sleeve, external protective sleeve, sealing sleeve and locking nut; the internal sleeve is used for sleeving the end of the adjacent two wire sections; the external protective sleeve is used for sleeving the external sleeve; one sealing sleeve is arranged at each end of the internal sleeve; the sealing sleeve is used for sleeving the wire; the internal sleeve is sealingly connected with the wire through the sealing sleeve; one locking nut is arranged at each end of the external protective sleeve; the locking nut is used for sleeving the wire; the external wall of the external protective sleeve at each end is provided with external thread; the locking nut is threadedly connected at each end of the external protective sleeve; when the locking nut is rotated and advanced, the sealing sleeve is compressed into the internal sleeve to generate radial contraction; the wire is locked in the internal sleeve through the contact friction force between the sealing sleeve and the wire and the internal sleeve.

7. A method for monitoring the vertical displacement of a nuclear power plant containment, characterized in that, The following steps are included: The total deformation of the detection wire is obtained by using the nuclear power plant containment displacement monitoring system according to any one of claims 1-6 for detection. The nuclear power plant containment vertical displacement monitoring data is obtained according to the initial length of the monitoring wire, the comprehensive linear expansion coefficient of the monitoring wire, the total deformation amount and the difference between the environmental temperatures before and after monitoring; the comprehensive linear expansion coefficient of the monitoring wire is obtained from the initial length of the monitoring wire, the linear length and the linear expansion coefficient of the straight section monitoring wire, the linear length and the linear expansion coefficient of the monitoring wire at the mold box, and the linear length and the linear expansion coefficient of the monitoring wire at the connection.

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