High-temperature-resistant and high-voltage-resistant radio frequency cable for nuclear power station

Abstract

The utility model discloses a high temperature and high pressure resistant radio frequency cable for a nuclear power station, which comprises an inner conductor, the inner conductor is arranged at the central position of the radio frequency cable, an insulating layer, a shielding layer and a sheath layer are sequentially coated on the circumference of the inner conductor from the inner layer to the outer layer, the radio frequency cable also comprises an outer armor layer, and the outer armor layer is coated on the circumferential outer side of the sheath layer. The outer armor layer is made of metal wires. The utility model provides a radio frequency cable scheme which is extremely low in attenuation, resistant to large-dose irradiation, resistant to high temperature and high pressure and capable of meeting the requirements of low smoke, zero halogen and flame retardance.

Description

Technical Field

[0001] The utility model relates to a radio frequency cable, in particular to a high temperature and high pressure resistant radio frequency cable for a nuclear power station. Background Art

[0002] In some special places within a nuclear power plant, such as the pit for storing spent fuel inside the containment and the spent fuel pool outside the containment, although the nuclear radiation dose to the components outside the pool is low under normal circumstances, in the event of an beyond-design basis accident or a serious accident, the equipment must withstand high-temperature water vapor and large doses of nuclear radiation. The equipment inside the containment must also withstand high pressure and boric acid water spraying and other conditions.

[0003] Electronic devices have limited resistance to temperature and radiation, and some electronic components need to be placed in a mild environment. Therefore, the guided wave radar level meter used for the above-mentioned pit or spent fuel pool level monitoring needs to be split, with the RF signal transmitter and receiver installed in different places and the waveguide head at a long distance, which may exceed 70m. The RF cable needs to have minimal signal attenuation to achieve accurate measurement. And the RF cable needs to be able to withstand high-intensity radiation and short-term high-temperature and high-pressure environments.

[0004] Prior art CN205488444U discloses a low-attenuation, high-power, high-temperature coaxial radio frequency cable, the main structure of which includes an inner conductor layer, an insulating layer, a shielding layer, and a sheath layer. The insulating layer is made of low-density polytetrafluoroethylene, and the sheath layer is made of polyperfluoroethylene propylene. These two fluorine-containing materials have a small relative dielectric constant and low dielectric loss, but this type of fluoroplastic contains halogens. The hydrogen halide gas produced by the combustion of halogen materials can cause damage to the human body and electronic equipment, and cannot meet the requirements of low-smoke, halogen-free, and flame-retardant properties in important places in nuclear power plants. Secondly, fluorinated materials have poor radiation resistance and are prone to loss of performance.

[0005] Prior art CN210837254U discloses a multifunctional protective armor for radio frequency cables, including an armor body, which is composed of a rubber layer, a steel wire layer and a protective tube, and a bottom plate is provided at the bottom of the armor body, a steel wire layer is sleeved inside the protective tube, and the inner surface of the steel wire layer is glued to the rubber layer, and a shielding layer is provided between the steel wire layer and the rubber layer. The main function of the armor layer is to improve the mechanical protection strength of the cable, and does not involve the protection effect against high temperature and high pressure.

[0006] In view of the above technical problems, the present utility model is specially introduced. Summary of the invention

[0007] The main purpose of the utility model is to provide a high temperature and high pressure resistant radio frequency cable for nuclear power plants, which is used to propose a radio frequency cable solution with extremely low attenuation, resistance to large doses of radiation, resistance to high temperature and high pressure, and meeting the requirements of low smoke and halogen-free flame retardancy.

[0008] In order to achieve the above-mentioned purpose, the utility model proposes a high temperature and high pressure resistant radio frequency cable for a nuclear power plant, comprising an inner conductor, wherein the inner conductor is located at the center of the radio frequency cable, and the inner conductor is sequentially covered with an insulating layer, a shielding layer and a sheath layer from the inner layer to the outer layer in the circumferential direction, and also comprises an outer armor layer, wherein the outer armor layer is covered on the circumferential outer side of the sheath layer, and the outer armor layer is made of metal wire.

[0009] Furthermore, the outer armor layer is a sleeve woven from steel wires.

[0010] Furthermore, the thickness of the outer armor layer is in the range of 0.3 to 0.5 mm.

[0011] Furthermore, the diameter of the steel wire used to braid the outer armor layer is in the range of 0.16 to 0.2 mm.

[0012] Furthermore, the sheath layer is made of low-smoke halogen-free flame-retardant cross-linked polyolefin.

[0013] Furthermore, the thickness of the sheath layer ranges from 1 to 1.3 mm.

[0014] Furthermore, the insulating layer is made of radiation cross-linked polyethylene, and the thickness of the insulating layer is in the range of 2.8 to 3.1 mm.

[0015] Furthermore, the shielding layer is woven with silver-plated metal wires.

[0016] Furthermore, the shielding layer is woven from the silver-plated metal wires with a diameter ranging from 1 to 1.5 mm.

[0017] Furthermore, the inner conductor is made of silver-plated copper stranded wire, and the diameter of the silver-plated copper stranded wire is in the range of 1 to 1.5 mm.

[0018] By applying the technical solution of the utility model, at least the following beneficial effects are achieved:

[0019] 1. The radio frequency cable of the utility model improves the ability of the radio frequency cable to withstand high temperature and high pressure for a short time by arranging an outer armor layer on the outside of the sheath layer, and effectively prevents the problem of micro-deformation of the sheath layer caused by high temperature and high pressure.

[0020] 2. The radio frequency cable of the utility model adopts cross-linked polyolefin through the sheath layer and irradiated cross-linked polyethylene through the insulation layer, which improves the radiation resistance of the radio frequency cable. The nuclear radiation resistance index can reach 500KGy or even MGy level.

[0021] 3. The radio frequency cable of the utility model is designed with an inner conductor of silver-plated copper stranded wire and a shielding layer of silver-plated wire weaving, so that the signal attenuation on the inner and outer conductors is less. The insulation layer is made of irradiated cross-linked polyethylene, which is a material with excellent radiation resistance and low dielectric constant, and can achieve an extremely low attenuation rate, with an attenuation of less than 0.4dB / m at a frequency of 1GHz and less than 0.6dB / m at a frequency of 3GHz.

[0022] 4. The radio frequency cable of the utility model adopts low-smoke halogen-free flame-retardant modified cross-linked polyolefin through the sheath layer, which does not contain halogen and can meet the requirements of low-smoke halogen-free flame retardancy in important places of nuclear power plants, and has high safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0024] Figure 1 A schematic diagram of a radio frequency cable according to an embodiment is shown.

[0025] The above drawings include the following reference numerals:

[0026] 1. Inner conductor; 2. Insulation layer; 3. Shielding layer; 4. Sheath layer; 5. Outer armor layer. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] The present invention is further described in detail below in conjunction with specific embodiments, and these embodiments cannot be understood as limiting the scope of protection claimed by the present invention. The term "including" indicates the existence of a feature when used, but does not exclude the existence or addition of one or more other features; the orientation or position relationship indicated by the terms "lateral", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; in addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0029] In the description, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, in the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0030] Example:

[0031] The utility model proposes a high temperature and high pressure resistant radio frequency cable for nuclear power plants, such as Figure 1 As shown, it includes an inner conductor 1, which is located at the center of the radio frequency cable. The inner conductor 1 is covered with an insulating layer 2, a shielding layer 3 and a sheath layer 4 in sequence from the inner layer to the outer layer in the circumferential direction. The radio frequency cable also includes an outer armor layer 5. The outer armor layer 5 is covered on the outer side of the sheath layer 4 in the circumferential direction, and the outer armor layer 5 is made of metal wire.

[0032] Specifically, the outer armor layer 5 is coated on the outermost layer of the RF cable. Preferably, the outer armor layer 5 is a sleeve woven from steel wire. Further preferably, the thickness of the outer armor layer 5 is in the range of 0.3 to 0.5 mm, and the diameter of the steel wire of the woven outer armor layer 5 is in the range of 0.16 to 0.2 mm. Through experiments, the thickness of the outer armor layer under this parameter is moderate, and it has a small bending radius to facilitate wiring, and can also provide better protection for the inner layer of the RF cable, can withstand a certain high temperature and high pressure, and has a certain flame retardant effect.

[0033] In some special places in nuclear power plants, the environment will become very harsh under accident conditions. The radio frequency cable withstands short-term high temperature and high pressure environment, such as 24 hours, 190°C high temperature and 0.5MPa high pressure, and the plastic is prone to softening and deformation at the connection part. By providing the outer armor layer 5, the ability of the radio frequency cable to withstand high temperature and high pressure for a short time is improved, and the problem of micro-deformation of the sheath layer due to high temperature and high pressure is effectively prevented. The sheath layer 4 is made of low-smoke halogen-free flame-retardant cross-linked polyolefin. The insulating layer 2 is made of irradiated cross-linked polyethylene. Preferably, the thickness of the sheath layer 4 is in the range of 1 to 1.3 mm, and the thickness of the insulating layer 2 is in the range of 2.8 to 3.1 mm.

[0034] The above design can meet the requirement of radiation resistance index ≥500KGy in some places of nuclear power plants. The manufacturing of the insulation layer 2 and the sheath layer 4 uses the radiation cross-linking process, which can not only improve the mechanical properties, heat resistance, chemical corrosion resistance and aging resistance of the material, but also improve the radiation resistance of the radio frequency cable. The nuclear radiation resistance index can reach 500KGy or even MGy level.

[0035] In addition, the sheath layer uses low-smoke halogen-free flame-retardant modified cross-linked polyolefin, which does not contain halogen and can meet the requirements of low-smoke halogen-free flame retardancy in important places in nuclear power plants, and has higher safety.

[0036] The shielding layer 3 of the radio frequency cable of the utility model is woven with silver-plated metal wires. Preferably, the shielding layer 3 is woven with silver-plated metal wires with a diameter range of 1 to 1.5 mm. The inner conductor 1 is made of silver-plated copper stranded wire, and the diameter range of the silver-plated copper stranded wire is 1 to 1.5 mm. In some nuclear power plant sites, electronic components must avoid accident conditions in the fuel plant, and the separation distance must reach 70m, plus a measurement range of about 10m. The high-frequency signal travels about 160m from the transmitter to the receiver, and the radio frequency cable must have very little signal attenuation to achieve accurate measurement.

[0037] By designing the diameter of the inner conductor to use silver-plated copper stranded wire and the shielding layer to be woven with silver-plated wire, the signal attenuation on the inner and outer conductors is reduced. The insulation layer is made of irradiated cross-linked polyethylene, which is a material with excellent radiation resistance and low dielectric constant. It can achieve an extremely low attenuation rate, with an attenuation of less than 0.4dB / m at a frequency of 1GHz and less than 0.6dB / m at a frequency of 3GHz.

[0038] In summary, from the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0039] 1. The radio frequency cable of the utility model improves the ability of the radio frequency cable to withstand high temperature and high pressure for a short time by arranging an outer armor layer on the outside of the sheath layer, and effectively prevents the problem of micro-deformation of the sheath layer caused by high temperature and high pressure.

[0040] 2. The radio frequency cable of the utility model adopts cross-linked polyolefin through the sheath layer and irradiated cross-linked polyethylene through the insulation layer, which improves the radiation resistance of the radio frequency cable. The nuclear radiation resistance index can reach 500KGy or even MGy level.

[0041] 3. The radio frequency cable of the utility model is designed with an inner conductor of silver-plated copper stranded wire and a shielding layer of silver-plated wire weaving, so that the signal attenuation on the inner and outer conductors is less. The insulation layer is made of irradiated cross-linked polyethylene, which is a material with excellent radiation resistance and low dielectric constant, and can achieve an extremely low attenuation rate, with an attenuation of less than 0.4dB / m at a frequency of 1GHz and less than 0.6dB / m at a frequency of 3GHz.

[0042] 4. The radio frequency cable of the utility model adopts low-smoke halogen-free flame-retardant modified cross-linked polyolefin through the sheath layer, which does not contain halogen and can meet the requirements of low-smoke halogen-free flame retardancy in important places of nuclear power plants, and has high safety.

[0043] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A high temperature and high pressure resistant radio frequency cable for a nuclear power plant, comprising an inner conductor (1), the inner conductor (1) being located at the center of the radio frequency cable, the inner conductor (1) being covered with an insulating layer (2), a shielding layer (3) and a sheath layer (4) in sequence from the inner layer to the outer layer in the circumferential direction, characterized in that: The invention also comprises an outer armor layer (5), the outer armor layer (5) is coated on the circumferential outer side of the sheath layer (4), and the outer armor layer (5) is made of metal wire; the manufacturing process of the insulating layer (2) and the sheath layer (4) both uses a radiation cross-linking process; the sheath layer (4) uses low-smoke halogen-free flame-retardant cross-linked polyolefin; the insulating layer (2) uses radiation cross-linked polyethylene, and the thickness of the insulating layer (2) ranges from 2.8 to 3.1 mm.

2. The radio frequency cable according to claim 1, characterized in that: The outer armor layer (5) is a sleeve formed by braiding steel wires.

3. The radio frequency cable according to claim 2, characterized in that: The thickness of the outer armor layer (5) is in the range of 0.3 to 0.5 mm.

4. The radio frequency cable according to claim 3, characterized in that: The diameter of the steel wire used to braid the outer armor layer (5) is in the range of 0.16 to 0.2 mm.

5. The radio frequency cable according to claim 4, characterized in that: The thickness of the sheath layer (4) is in the range of 1 to 1.3 mm.

6. The radio frequency cable according to claim 1, characterized in that: The shielding layer (3) is woven from silver-plated metal wires.

7. The radio frequency cable according to claim 6, characterized in that: The shielding layer (3) is woven from the silver-plated metal wires having a diameter ranging from 1 to 1.5 mm.

8. The radio frequency cable according to claim 1, characterized in that: The inner conductor (1) is made of silver-plated copper stranded wire, and the diameter of the silver-plated copper stranded wire is in the range of 1 to 1.5 mm.

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