Radiation-resistant long-life low-noise coaxial cable for nuclear power station

Abstract

The utility model discloses a radiation-resistant long-life low-noise coaxial cable for a nuclear power station, which comprises a conductor formed by twisting tinned soft copper, and a wrapping semi-conductive layer, an insulating layer, an extruded semi-conductive layer, a comprehensive shielding structure, a wrapping high-temperature-resistant layer and an outer sheath are sequentially arranged outside the conductor. The tinned soft copper conductors are stranded, so that the structural stability is ensured, and oxidation is avoided; the insulating layer is made of radiation-resistant and long-service-life crosslinked polyethylene, so that the transmission performance is ensured to be stable; noise is reduced through the semi-conductive layer, and signal quality is improved; a comprehensive shielding structure is adopted, so that the electromagnetic compatibility is enhanced; the high-temperature-resistant layer is arranged to meet the high-temperature requirement of the And the outer sheath is made of a radiation-resistant polyolefin material, so that the mechanical property and the service life are ensured. Overall performance is excellent, and the system is suitable for complex environments.

Description

Technical Field

[0001] This utility model relates to the field of cable technology, specifically to a radiation-resistant, long-life, low-noise coaxial cable for nuclear power plants. Background Technology

[0002] Nuclear power generation is recognized worldwide as one of the cleanest energy sources, and it has advantages such as stable and large power generation. In recent years, my country has invested heavily in nuclear power generation, with the number of nuclear power plants under construction and planned to be built ranking first in the world. The construction of nuclear power plants requires a large number of coaxial cables with radiation resistance, long lifespan, and low noise. The coaxial cables used in the construction of nuclear power plants are required to have stable characteristic impedance, radiation resistance, halogen-free, low smoke, flame retardancy, low attenuation, low noise, and long lifespan, and they must be able to work normally under LOCA simulation test conditions. Ordinary coaxial cables cannot meet the above requirements. Utility Model Content

[0003] The technical problem to be solved by the utility model: The purpose of this utility model is to overcome the above-mentioned defects of traditional coaxial cables in the prior art and provide a radiation-resistant, long-life, low-noise coaxial cable for nuclear power plants. It can maintain stable transmission performance in extreme environments, and at the same time has excellent mechanical properties and radiation resistance, ensuring the safe operation of nuclear power plants.

[0004] Technical solution: To achieve the above objectives, the technical solution provided by this utility model is as follows: a radiation-resistant, long-life, low-noise coaxial cable for nuclear power plants, comprising a conductor made of tin-plated soft copper stranded together, and the conductor being sequentially provided with a wrapped semi-conductive layer, an insulating layer, an extruded semi-conductive layer, a comprehensive shielding structure, a wrapped high-temperature resistant layer, and an outer sheath.

[0005] As a further improvement of this utility model, the conductor adopts a second type of tin-plated soft copper, with a 1+6 stranded structure and a stranding pitch between 7.5 and 10.0 mm.

[0006] As a further improvement of this utility model, the semiconducting wrapping tape is overlapped and wrapped around the conductor, the resistivity of the semiconducting wrapping tape is not greater than 5×104Ω.cm, and the overlap rate is between 5% and 15%.

[0007] As a further improvement of this utility model, an insulating layer is provided outside the semiconductive layer. The insulation has a dielectric constant of not more than 2.3 and a dielectric loss tangent of not more than 5 × 10⁻⁶. -5 Irradiated cross-linked polyethylene materials with a radiation dose tolerance of not less than 1540 kGy.

[0008] As a further improvement of this utility model, the eccentricity of the insulation layer is no more than 5%, and the ellipticity of the insulated wire core is no more than 0.12mm.

[0009] As a further improvement of this utility model, a radiation-resistant, low-resistivity semi-conductive polyethylene material is extruded and coated outside the insulating layer to form an extruded semi-conductive layer with a resistivity of not more than 100 Ω·cm.

[0010] As a further improvement of this utility model, a comprehensive shielding structure consisting of two layers of tin-plated copper wire braid and two layers of aluminum-plastic composite tape wrapped around the extruded semi-conductive layer is provided. From the inside out, the structure consists of a braided layer and an aluminum-plastic composite tape layer.

[0011] As a further improvement of this utility model, the overlap rate of the aluminum-plastic composite belt is between 5% and 15%, and the braiding density of the tin-plated copper wire is between 90% and 95%.

[0012] As a further improvement of this utility model, the shielding structure is formed by overlapping and wrapping high-temperature resistant polyimide tape to form a high-temperature resistant wrapping layer. The nominal thickness of the tape is 0.04mm, the number of tape layers is 2, and the overlap rate ranges from 15% to 25%.

[0013] As a further improvement of this utility model, the cable has a characteristic impedance of 75±3Ω / km, an attenuation constant of no more than 0.2dB / m, and a working capacitance of no more than 70pF / m at a frequency of 200MHz.

[0014] Beneficial effects

[0015] 1. Traditional coaxial cable conductors are prone to oxidation and instability under high temperature and high pressure environments. This technical solution uses tin-plated soft copper conductors to control the stranding pitch, ensuring conductor structure stability, good DC resistance consistency, and effectively avoiding oxidation problems.

[0016] 2. Traditional insulation materials are prone to aging in radiation environments, leading to a decline in transmission performance. The insulation layer of this technical solution uses low dielectric constant, radiation resistant, and long-life cross-linked polyethylene insulation material, which has the characteristics of high temperature resistance and strong radiation resistance. It can maintain stable transmission performance in long-term high temperature and high radiation environments, and can still maintain very good transmission performance after LOCA simulation test.

[0017] 3. This technical solution uses a semi-conductive tape to wrap the conductor and a semi-conductive layer to extrude the insulation. The electric field is homogenized by the semi-conductive layer with low resistivity, which effectively reduces noise and improves signal transmission quality.

[0018] 4. The shielding layer is crucial for preventing external interference and maintaining signal stability. This technical solution employs a comprehensive shielding structure consisting of two layers of tinned copper wire braid and two layers of aluminum-plastic composite tape overlapping and wrapping. This structure provides excellent electromagnetic compatibility and shielding effectiveness, ensuring stable and reliable signal transmission via coaxial cable.

[0019] 5. Nuclear power plant environments are complex, placing extremely high demands on the high-temperature resistance and flame-retardant properties of cables. This technical solution employs two layers of high-temperature resistant polyimide tape wrapped around the shielding layer to form a high-temperature resistant layer, further enhancing the cable's flame-retardant properties. Simultaneously, the cable's temperature resistance can reach 260℃, meeting the high-temperature environmental requirements of nuclear power plants.

[0020] 6. The outer sheath is the protective layer of the cable and needs to have excellent radiation resistance and mechanical properties. This technical solution uses radiation-resistant, halogen-free, low-smoke, and flame-retardant polyolefin material with irradiation cross-linking as the outer sheath to ensure that the cable still has good mechanical properties and service life after high radiation aging. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a radiation-resistant, long-life, low-noise coaxial cable for nuclear power plants according to this utility model.

[0022] Explanation of the labels in the diagram:

[0023] 1. Conductor; 2. Wrapped semi-conductive layer; 3. Insulating layer; 4. Extruded semi-conductive layer; 5. Comprehensive shielding structure; 51. Braided layer; 52. Aluminum-plastic composite tape layer; 6. Wrapped high-temperature resistant layer; 7. Outer sheath. Detailed Implementation

[0024] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and specific embodiments.

[0025] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0028] A radiation-resistant, long-life, low-noise coaxial cable for nuclear power plants includes a conductor 1. The conductor 1 is made of a second type of tin-plated soft copper conductor, which is formed by stranding seven tin-plated copper wires with an outer diameter of 0.3 mm and an outer diameter of 0.3 ± 0.02 mm for each wire. The stranding pitch is controlled between 7.5 and 10.0 mm. The surface should be smooth, free of oil stains, burrs that damage the insulation, sharp edges, and protruding or broken single wires. After stranding, the conductor structure is stable, the DC resistance of the conductor is uniform, and the tin-plated copper wire has good anti-oxidation properties.

[0029] Conductor 1 is wrapped with a low-resistivity semiconducting strip with a resistivity not greater than 5 × 10⁻⁶. 4 Ω.cm is defined as the 2nd layer of the semi-conductive wrapping layer. The semi-conductive nylon tape is used for overlapping wrapping. There should be no omissions during wrapping. The overlap rate of the wrapping is between 5% and 15%.

[0030] An insulating layer 3 is provided outside the semiconductive layer 2. The insulating layer 3 is made of cross-linked polyethylene insulating material with low dielectric constant, radiation resistance and long life. The radiation dose resistance is not less than 1540kGy. The insulating layer 3 is produced by extrusion. During the extrusion insulation, the eccentricity of the insulating layer 3 is not greater than 5%, and the ellipticity of the insulated wire core is not greater than 0.12mm. This ensures the stability of the electrical performance and transmission performance of the product. The copper wire ensures that the cable attenuation is not greater than 0.2dB / m (200MHz) and that the cable attenuation constant meets the requirements.

[0031] The insulation layer 3 is extruded with a radiation-resistant, low-resistivity semi-conductive polyethylene material, which is defined as the extruded semi-conductive layer 4. The semi-conductive polyethylene material made by adding conductive carbon black or graphite to the polyethylene material has a resistivity of no more than 100 Ω·cm and a thickness controlled between 0.1 and 0.2 mm. This ensures noise reduction while avoiding an increase in the dielectric constant of the insulation.

[0032] The wrapped semiconductive layer 2 and the extruded semiconductive layer 4 adopt a two-layer semiconductive layer structure. The semiconductive layer can play a transition role between the metal and polymer material layers, effectively reducing the generation of cable noise, thereby improving the signal transmission quality.

[0033] The cable is surrounded by an extruded semi-conductive layer 4, and an integrated shielding structure 5 consisting of two layers of tinned copper wire braid and two layers of aluminum-plastic composite tape wrapped around it. From the inside out, the structure comprises a braided layer 51 and an aluminum-plastic composite tape layer 52. The braided layer 51 uses two layers of tinned copper wire with an outer diameter of 0.15mm and a braiding density between 90% and 95%. The copper wire has low resistivity and good explosion-proof properties. The aluminum-plastic composite tape layer 52 has a nominal thickness of 0.04mm, two layers, and an overlap rate ranging from 5% to 25%, providing better shielding for the cable. This integrated shielding structure, consisting of two layers of tinned copper wire braid and two layers of aluminum-plastic composite tape wrapped around it, has strong anti-interference capabilities and good electromagnetic compatibility, ensuring stable and reliable signal transmission via the coaxial cable and thus guaranteeing the operational safety of the nuclear power plant.

[0034] The outer layer of the integrated shielding structure 5 is formed by overlapping and wrapping high-temperature resistant polyimide tape to form a high-temperature resistant layer 6. The nominal thickness of the tape is 0.04mm, the number of tape layers is 2, and the overlap rate ranges from 15% to 25%. Its temperature resistance can reach 260℃, which has a good high-temperature isolation effect and makes the flame retardant performance of the cable even better.

[0035] An outer sheath 7 is installed outside the high-temperature resistant layer. The outer sheath 7 is made of radiation-resistant, halogen-free, low-smoke, flame-retardant polyolefin material with a nominal thickness of not less than 1.5 mm. This ensures that the cable retains excellent mechanical properties after high-radiation aging, guaranteeing its service life in high-temperature and high-radiation environments. In this technical solution, the insulation layer 3 and outer sheath 7 are made of polyolefin material with a cumulative radiation dose resistance of not less than 1540 kGy, and the dielectric constant of the insulation material is not greater than 2.3. This ensures stable cable transmission performance and a 60-year lifespan in high-radiation environments.

[0036] The conductor 1 of this invention uses tin-plated soft copper stranded conductors with a small stranding pitch, ensuring a stable conductor structure, good DC resistance consistency, and effectively preventing oxidation of the cable conductor under high temperature and high pressure. The insulation layer 3 uses cross-linked polyethylene with low dielectric constant, radiation resistance, and long lifespan. It has a high temperature resistance rating and can operate normally in long-term high temperature and high radiation environments. After LOCA simulation test, it can still maintain very good transmission performance. The conductor 1 is wrapped with a semi-conductive layer 2, and the insulation layer 3 is wrapped with an extruded semi-conductive layer 4. The semi-conductive layer has the characteristics of low resistivity and strong radiation resistance. During use, it can homogenize the electric field generated at high frequencies and effectively reduce noise. The shielding layer uses two layers of tin-plated copper wire braid + two layers of aluminum-plastic composite tape to form a comprehensive shielding structure, which makes the cable electromagnetic compatibility better. The shielding structure is wrapped with two layers of high temperature resistant polyimide tape, which makes the cable flame retardant performance better. The outer sheath is made of radiation-resistant, halogen-free, low-smoke, and flame-retardant polyolefin material with irradiation cross-linking.

[0037] At a frequency of 200MHz, the cable has a characteristic impedance of 75±3Ω / km, an attenuation constant of no more than 0.2dB / m, and a working capacitance of no more than 70pF / m, ensuring normal signal transmission. Therefore, the cable has good electrical performance and signal transmission performance at a frequency of 200MHz, ensuring the reliability and stability of the cable in high-frequency signal transmission.

[0038] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A long life, low noise, radiation resistant coaxial cable for use in nuclear power plants, characterized by: The conductor is made of tinned soft copper strands, and the conductor is provided with a semi-conductive layer, an insulating layer, an extruded semi-conductive layer, a comprehensive shielding structure, a high-temperature resistant layer and an outer sheath in sequence.

2. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 1, characterized by: The conductor is made of the second tinned soft copper, and the conductor is twisted in a 1+6 structure with a pitch of 7.5-10.0 mm.

3. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 1, characterized by: The semi-conductive layer is overlapped and wrapped around the conductor, and the resistivity of the semi-conductive layer is not more than 5×104 Ω·cm, and the overlapping rate is 5-15%.

4. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 3, characterized by: The insulating layer is arranged outside the semi-conductive layer, and the insulating layer is made of a material with dielectric constant not greater than 2.3 and dielectric loss tangent not greater than 5*10 -5 The irradiation cross-linking polyethylene material has radiation resistance of not less than 1540 kGy.

5. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 4, characterized in that: The eccentricity of the insulating layer is not more than 5%, and the ovality of the insulating core is not more than 0.12 mm.

6. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 1, characterized by: The extruded semi-conductive layer is formed by extruding a semi-conductive polyethylene material with low resistivity and radiation resistance outside the insulating layer, and the resistivity of the extruded semi-conductive layer is not more than 100 Ω·cm.

7. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 6, characterized in that: The comprehensive shielding structure is formed by overlapping and wrapping two layers of tinned copper wire braiding and two layers of aluminum-plastic composite tape outside the extruded semi-conductive layer, and the braiding layer and the aluminum-plastic composite tape layer are arranged in sequence from inside to outside.

8. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 7, characterized by: The overlapping rate of the aluminum-plastic composite tape is 5-15%, and the braiding density of the tinned copper wire is 90-95%.

9. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 1, characterized in that: The high-temperature resistant layer is formed by overlapping and wrapping a high-temperature resistant polyimide tape outside the comprehensive shielding structure, the nominal thickness of the tape is 0.04 mm, the number of layers of the tape is 2, and the overlapping rate is 15-25%.

10. The long life low noise radiation resistant coaxial cable for nuclear power plants according to claim 1, characterized in that: The characteristic impedance of the cable is 75±3 Ω / km at a frequency of 200 MHz, the attenuation constant is not more than 0.2 dB / m, and the working capacitance is not more than 70 pF / m.

Images