Flame-retardant cable for 1E-grade nuclear power station

Abstract

The utility model relates to the field of power cables, in particular to a flame-retardant cable for a 1E-grade nuclear power station, which comprises a wire core assembly, the wire core assembly is composed of at least three conductors, a first insulating layer is arranged on the outer side of each conductor, and a second insulating layer is arranged on the outer side of each first insulating layer; the periphery of the wire core assembly is provided with a corrosion-resistant filler, the wire core assembly and the corrosion-resistant filler are restrained into a whole through a polyester belt, the outer side of the polyester belt is provided with an inner protection layer, the outer side of the inner protection layer is provided with an outer protection layer, and a buffer layer is arranged between the inner protection layer and the outer protection layer; wherein the first insulating layer is made of a 125 DEG C irradiation crosslinking type halogen-free low-smoke flame-retardant polyolefin insulating material, and the second insulating layer is made of a flame-retardant EVA (Ethylene Vinyl Acetate) elastomer insulating material. Aiming at the technical problem that the service life of the existing cable for the nuclear power station is not long, the cable structure is improved, and the material selection of the layered structure is adjusted, so that the service life of the cable in the nuclear power station environment is prolonged under the condition that the electrical performance of the cable is met.

Description

Technical Field

[0001] This utility model relates to the field of power cables, specifically to a flame-retardant cable for Class 1E nuclear power plants. Background Technology

[0002] As a complex energy system, nuclear power plants rely heavily on power cables for transmitting electricity and signals. These cables connect the reactor, generator sets, control systems, and other critical equipment, ensuring the coordinated operation of all parts of the plant to generate and distribute electrical energy. The quality and performance of these cables directly impact the safe and stable operation of the nuclear power plant. High-quality cables guarantee stable power and signal transmission, preventing shutdowns or accidents caused by cable faults.

[0003] Therefore, the operating environment of nuclear power plants places higher demands on cables.

[0004] While existing flame-retardant power cables can still operate stably in extreme environments, their service life is inevitably significantly affected by the harsh conditions of high pressure, high temperature, and radiation inside nuclear power plants. In other words, there is still room for improvement in the service life of current power cables used in nuclear power plants to better cope with the complex environment of nuclear power plants and ensure stable performance throughout the entire life cycle of the nuclear power plant. Utility Model Content

[0005] To address the technical problem of short service life of existing nuclear power plant cables, this utility model provides a flame-retardant cable for Class 1E nuclear power plants. By improving the cable structure and adjusting the material selection of the layered structure, the flame-retardant cable for Class 1E nuclear power plants can improve its service life in the nuclear power plant environment while meeting electrical performance requirements.

[0006] The technical solution provided by this utility model is as follows: a flame-retardant cable for 1E-class nuclear power plants, comprising a core assembly, wherein the core assembly is composed of at least three conductors, each conductor having a first insulation layer on its outer side, and each first insulation layer having a second insulation layer on its outer side; a corrosion-resistant filler is provided around the core assembly, and the core assembly and the corrosion-resistant filler are constrained as a whole by a polyester tape, an inner sheath is provided on the outer side of the polyester tape, an outer sheath is provided on the outer side of the inner sheath, and a buffer layer is provided between the inner and outer sheaths; wherein, the first insulation layer is made of 125℃ irradiated cross-linked halogen-free low-smoke flame-retardant polyolefin insulation material, and the second insulation layer is made of flame-retardant EVA elastomer insulation material.

[0007] Optionally, the inner sheath is made of ethylene-vinyl acetate copolymer.

[0008] Optionally, the outer protective layer is made of polyetherimide specialty plastic.

[0009] Optionally, the buffer layer is made of leaded brass strip.

[0010] Optionally, the thickness of the leaded brass strip is 0.3mm-0.8mm.

[0011] Optionally, the leaded brass strip is a leaded brass strip with a wavy embossed pattern.

[0012] Optionally, the corrosion-resistant filler is made of fiberglass rope.

[0013] Optionally, the conductor is a tin-plated copper profile conductor.

[0014] Beneficial effects

[0015] Compared with the prior art, the technical solution provided by this utility model has the following beneficial effects: In view of the technical problem of the short service life of existing nuclear power plant cables, this utility model improves the cable structure and adjusts the material selection of the layered structure, thereby improving the service life of the 1E-class nuclear power plant flame-retardant cable in the nuclear power plant environment while meeting the electrical performance requirements. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a flame-retardant cable for a Class 1E nuclear power plant, as proposed in an embodiment of this utility model. Detailed Implementation

[0017] 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 embodiments.

[0018] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the relevant utility model and not intended to limit the utility model. Furthermore, it should be noted that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings. The terms "first," "second," etc., used in this utility model are provided for the convenience of describing the technical solution of this utility model and have no specific limiting effect; they are all general terms and do not constitute a limitation on the technical solution of this utility model. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the 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 on this utility model. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict, all of which are within the scope of protection claimed by this utility model.

[0019] Combined with appendix Figure 1 This embodiment proposes a flame-retardant cable for 1E-class nuclear power plants, including a core assembly. The core assembly consists of at least three conductors 1. Each conductor 1 has a first insulation layer 2 on its outer side, and each first insulation layer 2 has a second insulation layer 3 on its outer side. Corrosion-resistant filler 4 is provided around the core assembly. The core assembly and the corrosion-resistant filler 4 are constrained into a whole by a polyester tape 5. An inner sheath 6 is provided on the outer side of the polyester tape 5, and an outer sheath 8 is provided on the outer side of the inner sheath 6. A buffer layer 7 is provided between the inner sheath 6 and the outer sheath 8. The first insulation layer 2 is made of 125°C irradiated cross-linked halogen-free low-smoke flame-retardant polyolefin insulation material, and the second insulation layer 3 is made of flame-retardant EVA elastomer insulation material.

[0020] The flame-retardant cable for Class 1E nuclear power plants in this embodiment is designed with a multi-core, multi-layered structure. Specifically, several conductors 1 constitute a core assembly, and an inner sheath 6, a buffer layer 7, and an outer sheath 8 are sequentially designed on the outside of the core assembly. For each conductor 1 in the core assembly, a first insulation layer 2 and a second insulation layer 3 are sequentially provided on the outside. The material of the first insulation layer 2 is selected as 125°C irradiated cross-linked halogen-free, low-smoke flame-retardant polyolefin insulation material, and the material of the second insulation layer 3 is selected as flame-retardant EVA elastomer insulation material. Thus, the flame-retardant cable for Class 1E nuclear power plants in this embodiment improves the service life in the nuclear power plant environment while meeting the electrical performance requirements.

[0021] In this embodiment, the first insulation layer 2 and the second insulation layer 3 constitute a double insulation layer structure, which can be extruded using a double-layer co-extrusion process in industry. The first insulation layer 2 uses a 125℃ irradiated cross-linked halogen-free, low-smoke, flame-retardant polyolefin insulation material, meeting the halogen-free flame-retardant requirements of nuclear power plant cables. The second insulation layer 3 uses a flame-retardant EVA elastomer insulation material, increasing the cable's heat resistance temperature from 90℃ to 125℃. It also possesses excellent radiation resistance and chemical resistance, effectively protecting the first insulation layer and ensuring more stable operation. In this embodiment, the combination of the first insulation layer 2 and the second insulation layer 3 better meets the requirements of the nuclear power plant's operating environment, thus allowing the cable to operate normally for far longer than the 60-year design life of a nuclear power plant.

[0022] In this embodiment, conductor 1 is preferably a tin-plated copper wire conductor. This type of conductor is generally made of irregularly shaped tin-plated copper single wires stranded together, and the structure between its single wires (monochories) is more compact than that of ordinary conductor 1. Increasing the compactness between the conductor monochories can effectively reduce the probability of contaminants entering conductor 1 and improve corrosion resistance. In addition, the tin-plated conductor monochories can greatly improve the oxidation resistance and corrosion resistance of copper, thereby further improving the service life of the cable.

[0023] In this embodiment, the corrosion-resistant filler 4 is preferably made of fiberglass rope. Fiberglass rope has the characteristics of not absorbing water, has good corrosion resistance, does not contain halogen elements, and has excellent aging resistance. In addition, it has high strength, a smooth appearance, and is easy to use in combination with polyester tape 5. Both polyester tape 5 and fiberglass rope are excellent cable product accessories. This combination design can greatly improve the chemical corrosion resistance of this product.

[0024] Furthermore, in this embodiment, the inner sheath 6 is preferably made of ethylene-vinyl acetate copolymer. The copolymer of ethylene and vinyl acetate has excellent radiation resistance, chemical resistance, good mechanical and processing properties, high temperature resistance, and is less prone to dripping during combustion. Its operating temperature range can reach -70℃ to 125℃, and its low-temperature performance is also greatly improved. It can withstand temperatures as low as -70℃ and as high as 125℃, extending its service life under the same cable load capacity or load conditions.

[0025] In this embodiment, the outer sheath 8 can be made of polyetherimide special plastic. This material is halogen-free, non-toxic, and flame-retardant. It also has good radiation resistance, high and low temperature resistance, and wear resistance. It can be used at -160℃ to 180℃, making it more suitable for nuclear power plant environments.

[0026] Between the inner sheath 6 and the outer sheath 8, this embodiment provides a buffer layer 7. The buffer layer 7 is preferably made of leaded brass strip with a wavy embossing, and the thickness of the leaded brass strip is preferably 0.5 mm, with a lead content ≤3%. In actual production, the buffer layer 7 is manufactured using a 0.5 mm leaded brass strip embossing process. This leaded brass strip has good wear resistance and corrosion resistance, and lead can effectively block the passage of gamma rays and X-rays, reducing the impact of nuclear radiation on the internal components of the cable, thereby improving the cable's service life. The embossing process uses a special embossing mold to press the flat leaded brass strip into a wavy pattern. The inner side of the buffer layer 7 is flat and tightly pressed onto the inner sheath 6, while the outer side is wavy. This provides cushioning when the cable is subjected to external impact, improving the cable's compressive strength and preventing rodent bites.

[0027] 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 to this. 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 flame-retardant cable for a 1E class nuclear power plant, characterized by, The device includes a core assembly consisting of at least three conductors (1), each conductor (1) having a first insulating layer (2) on its outer side, and each first insulating layer (2) having a second insulating layer (3) on its outer side; the core assembly is surrounded by a corrosion-resistant filler (4), and the core assembly and the corrosion-resistant filler (4) are bound together as a whole by a polyester tape (5), the polyester tape (5) having an inner sheath (6) on its outer side, the inner sheath (6) having an outer sheath (8) on its outer side, and a buffer layer (7) being provided between the inner sheath (6) and the outer sheath (8); The first insulation layer (2) is made of halogen-free, low-smoke flame-retardant polyolefin insulation material irradiated at 125°C, and the second insulation layer (3) is made of flame-retardant EVA elastomer insulation material.

2. The flame-retardant cable for a Class 1E nuclear power plant according to claim 1, characterized in that, The inner protective layer (6) is made of ethylene-vinyl acetate copolymer.

3. The flame-retardant cable for a 1E class nuclear power plant according to claim 1, characterized by, The outer protective layer (8) is made of polyetherimide special plastic.

4. The flame-retardant cable for a 1E class nuclear power plant according to claim 1, characterized by, The buffer layer (7) is made of leaded brass strip.

5. A flame-retardant cable for a 1E class nuclear power plant according to claim 4, characterized in that, The thickness of the leaded brass strip is 0.3mm-0.8mm.

6. The flame-retardant cable for a 1E class nuclear power plant according to claim 4, characterized by The leaded brass strip is a leaded brass strip with a wavy embossed pattern.

7. The flame-retardant cable for a 1E class nuclear power plant according to claim 1, characterized by, The corrosion-resistant filler (4) is made of glass fiber rope.

8. The flame-retardant cable for a 1E class nuclear power plant according to claim 1, characterized by, The conductor (1) is a tin-plated copper wire conductor.

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