1E-grade cable for nuclear power device

Abstract

The utility model relates to the technical field of cables, in particular to a 1E-grade cable for a nuclear power device, which comprises at least one conductor, a heterogeneous double-layer co-extrusion insulating layer is extruded on the outer wall of each conductor, a wrapping tape is lapped on the outer wall of each heterogeneous double-layer co-extrusion insulating layer to form an insulating wire core, and the insulating wire cores are arranged in a filling body. Two kinds of heterogeneous wrapping tapes, a shielding layer, an inner sheath layer, an armor layer and an outer sheath layer are sequentially wrapped outside the filling body, and the heterogeneous double-layer co-extrusion insulating layer comprises an inner insulating layer and an outer insulating layer. The cable is compact in structure and good in stability, the sheath layer is made of halogen-free low-smoke radiation-resistant cross-linked polyolefin, and the radiation-resistant performance and the mechanical performance are excellent.

Description

TECHNICAL FIELD

[0001] The utility model relates to cable technical field, concretely is 1E grade cable for nuclear power device. BACKGROUND

[0002] The statements in this part only provide the background technical information related to the utility model, and do not necessarily constitute prior art.

[0003] 1E grade cable in nuclear power device refers to the safety grade cable of electrical system equipment that completes the functions such as reactor emergency shutdown, containment isolation, core emergency cooling, reactor residual heat export, reactor containment heat export and prevention of radioactive material discharge to the surrounding environment. The 1E grade cable in the prior art has the shortcomings of unsatisfactory performance in aspects such as flame retardation, radiation resistance and service life. CONTENT OF UTILITY MODEL

[0004] In order to solve the technical problems in the background art, the utility model provides a 1E grade cable for nuclear power device, which has the characteristics of halogen-free low-smoke flame retardation, low toxicity, corrosion resistance, mold resistance, salt mist resistance, weather resistance, excellent electrical performance, strong radiation resistance and long service life, and can effectively meet the use environment of the 1E grade cable for nuclear power device.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] The utility model discloses a first aspect provides a kind of 1E grade cable for nuclear power device, including at least one conductor, each conductor outer wall extrusion package hetero double-layer co-extrusion insulation layer, hetero double-layer co-extrusion insulation layer outer wall is wrapped with wrapping tape to form insulated core, insulated core is placed in filler, filler is successively wrapped with two kinds of hetero wrapping tape, shielding layer, inner sheath layer, armoring layer and outer sheath layer, hetero double-layer co-extrusion insulation layer includes inner insulation layer and outer insulation layer, and the material of inner insulation layer and outer insulation layer is different.

[0007] As some possible implementation modes, the conductor is twisted by tinned copper wire.

[0008] As further limitation, the twist pitch is 16-20 times the outer diameter of the conductor, and the twist direction of the outermost layer is left, and the twist directions of adjacent layers are opposite.

[0009] As some possible implementation modes, the double-layer co-extrusion hetero insulation layer is formed by stacking irradiation cross-linked polyethylene inner insulation layer and irradiation cross-linked halogen-free low-smoke flame-retardant polyolefin outer insulation layer.

[0010] As some possible implementation modes, the outer wrapping tape of extrusion package hetero double-layer co-extrusion insulation layer is polyimide film.

[0011] As possible implementation, two kinds of heterogeneous tape is low smoke halogen-free flame-retardant tape and polyester tape.

[0012] As possible implementation, the shielding layer is tinned copper wire.

[0013] As possible implementation, the inner sheath layer and the outer sheath layer are made of the same material, but the extrusion method is different.

[0014] As possible implementation, the inner sheath layer and the outer sheath layer of the cable are made of radiation crosslinking halogen-free low smoke retardant polyolefin sheath material.

[0015] As possible implementation, the armor layer is tinned copper wire.

[0016] As possible implementation, the thickness ratio of the inner insulation layer and the outer insulation layer is 1:3.

[0017] As possible implementation, the filling is low smoke halogen-free flame-retardant material.

[0018] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0019] 1. The structure of the cable is compact and stable, the sheath layer is made of halogen-free low smoke and radiation crosslinking polyolefin, and the radiation resistance and mechanical properties are excellent; the outer wall of the conductor is provided with inner and outer double-layer insulation, which improves the insulation of the cable and ensures reliable electrical properties, and the cable is more stable during use.

[0020] 2. The adjacent layers of the insulated core are twisted in opposite directions, which can prevent the action force between the inner and outer layers from being offset.

[0021] 3. The gap between the insulated cores is filled with non-hygroscopic inorganic paper rope to round the cable, which significantly improves the flame retardant performance of the cable and meets the roundness requirement of the cable.

[0022] 4. The inner and outer insulation layers are processed by double-layer co-extrusion process, which is efficient and low in energy consumption, and avoids defects such as layering, wrinkling, delamination between the sheath layer and the insulation layer, and poor combination of the core and the insulation.

[0023] 5. The inner insulation layer, outer insulation layer, and sheath layer are extruded using irradiation crosslinking. During the irradiation crosslinking process, the insulation layer does not come into contact with moisture, reducing the probability of electrical performance problems caused by moisture ingress. Irradiation crosslinking is suitable for the production of special cables. High-energy electron beams modify the insulation material, breaking the original linear CH bonds, and then the molecular structure is recombined to form a random network molecular structure, improving the material's mechanical and physical properties, temperature resistance, and electrical properties. At the same time, because this material is made by irradiating organic thermoplastic materials with high-energy electron beams, transforming them from linear polymers into a three-dimensional network crosslinked structure, that is, converting thermoplastics into infusible hot solid substances, improving and enhancing physical and mechanical properties, and the irradiation crosslinking method avoids the destruction of low-smoke and halogen-free characteristics by chemical crosslinking. Attached Figure Description

[0024] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0025] Figure 1 This is a schematic diagram of the cross-sectional structure of a Class 1E cable for a nuclear power plant provided by this utility model.

[0026] In the diagram: 1. Conductor; 2. Inner insulation; 3. Outer insulation; 4. First wrapping tape; 5. Second wrapping tape; 6. Shielding layer; 7. Inner sheath; 8. Armor layer; 9. Outer sheath. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Terminology Explanation:

[0031] 1E class cable refers to the safety class cable of the electrical system equipment which can complete the functions of reactor emergency shutdown, containment isolation, reactor core emergency cooling, reactor residual heat removal, reactor containment heat removal and prevention of radioactive material discharge to the surrounding environment, etc.

[0032] According to the safety level and cable laying occasion, the 1E class cable for nuclear power plants can be divided into different categories, such as 1E class K1, K2 and K3. Among them, K3 class cable refers to the cable which can perform its specified functions outside the containment under normal conditions and seismic load.

[0033] The following examples give a kind of 1E class cable for nuclear power plants, which has the characteristics of halogen-free low smoke retardant, low toxicity, corrosion resistance, mold resistance, salt spray resistance, weather resistance, excellent electrical performance, strong radiation resistance and long service life, etc., which can effectively meet the use environment of 1E class cable for nuclear power plants.

[0034] Example one:

[0035] A kind of 1E class cable for nuclear power plants, comprising one or more conductors, the outer wall of the conductor is extruded with a heterogeneous double-layer co-extrusion insulation layer and wrapped with a tape, forming an insulated core and placed in a filler, the filler is wrapped with two kinds of heterogeneous tapes, a shielding layer, an inner sheath layer, an armor layer and an outer sheath layer in sequence, the heterogeneous double-layer co-extrusion insulation layer comprises an inner insulation layer and an outer insulation layer, and the inner insulation layer and the outer insulation layer are different in material.

[0036] As a possible implementation, the conductor is twisted by tinned copper wire.

[0037] As a further limitation, the twist pitch is 16-20 times the outer diameter of the conductor, and the twist direction of the outermost layer is left, and the twist direction of adjacent layers is opposite.

[0038] As a possible implementation, the double-layer co-extrusion heterogeneous insulation layer is composed of an irradiation cross-linked polyethylene inner insulation layer and an irradiation cross-linked halogen-free low smoke retardant polyolefin outer insulation layer.

[0039] As a possible implementation, the outer tape of the extruded heterogeneous double-layer co-extrusion insulation layer is a polyimide film.

[0040] As a possible implementation, the two kinds of heterogeneous tapes are low smoke halogen-free flame retardant tapes and polyester tapes.

[0041] As a possible implementation, the shielding layer is tinned copper wire.

[0042] As a possible implementation, the inner sheath layer and the outer sheath layer are the same in material but different in extrusion method.

[0043] As a possible implementation, the inner sheath layer and the outer sheath layer of the cable are made of irradiation cross-linked halogen-free low smoke retardant polyolefin sheath material.

[0044] As some possible implementations, the armor layer is tinned copper wire.

[0045] As some possible implementations, the inner insulation layer and the outer insulation layer thickness ratio is 1:3.

[0046] As some possible implementations, the filling is low-smoke halogen-free flame-retardant material.

[0047] The production method of the 1E grade cable described above, comprising the following steps: extruding the inner insulation layer and the outer insulation layer outside the conductor, irradiation cross-linking treatment of the inner insulation layer and the outer insulation layer, forming the insulated core, winding the insulated core, forming the cable core with multiple insulated cores, filling (if necessary) the cable core, after the cable winding, tinned copper wire braided shielding, then extruding the inner sheath layer and irradiation cross-linking treatment of the inner sheath layer, then using tinned copper wire braided armor, and finally extruding the outer sheath layer and irradiation cross-linking treatment of the outer sheath layer.

[0048] The inner insulation layer extrusion adopts double-thread screw rod, the outer insulation layer extrusion adopts low compression ratio screw rod, the conductor should be preheated to 90-100℃ before the insulation layer extrusion, the insulation material should be baked at 60±10℃ for 1-2 hours, the insulated core adopts segmented cooling, the first segment cooling water temperature is 60℃±10℃, and the second segment cooling water temperature is normal temperature; The inner sheath layer adopts low compression ratio screw rod on the extruder set and is extruded by extrusion mold, the material should be preheated at 60±10℃ for 1-2 hours before extrusion, and segmented cooling is adopted after extrusion, the first segment cooling water temperature is 60±10℃, and the second segment cooling water temperature is normal temperature; The outer sheath layer adopts low compression ratio screw rod on the extruder set and is extruded by semi-extrusion mold, the material should be preheated at 60±10℃ for 1-2 hours before extrusion, and segmented cooling is adopted after extrusion, the first segment cooling water temperature is 60±10℃, and the second segment cooling water temperature is normal temperature.

[0049] Specifically, as shown in Figure 1 A 1E grade cable for nuclear power device, comprising 61 conductors 1, the outer wall of the conductor 1 is extruded with a heterogeneous double-layer co-extrusion insulation layer, the heterogeneous double-layer co-extrusion insulation layer has a first wrapping tape 4 outside to form an insulated core, 61 insulated cores are cabled, a second wrapping tape 5, a shielding layer 6, an inner sheath layer 7, an armor layer 8, and an outer sheath 9.

[0050] The heterogeneous double-layer co-extrusion insulation layer comprises an inner insulation layer 2 and an outer insulation layer 3, and the inner insulation layer 2 and the outer insulation layer 3 are made of different materials, the material of the inner insulation layer 2 is cross-linked polyethylene material, the material of the outer insulation layer 3 is cross-linked halogen-free low-smoke flame-retardant polyolefin material, the materials of the first wrapping tape 4 and the second wrapping tape 6 are different, the material of the first wrapping tape 4 is polyimide film, and the material of the second wrapping tape 6 is low-smoke halogen-free flame-retardant wrapping tape + polyester tape, the shielding layer 6 adopts a tinned copper wire braided shield, the material of the inner sheath layer 7 is low-smoke halogen-free flame-retardant polyolefin, the material of the armor layer 8 is a tinned copper wire braided armor, and the material of the outer sheath layer 9 is low-smoke halogen-free flame-retardant polyolefin.

[0051] The cable structure of the embodiment is compact and stable, the sheath layer adopts halogen-free low-smoke and radiation-resistant cross-linked polyolefin, and the radiation-resistant performance and mechanical performance are excellent.

[0052] In the embodiment, the outer wall of the conductor adopts double-layer insulation, the insulation of the cable is improved, reliable electrical performance is ensured, and the cable is more stable in use.

[0053] In the embodiment, the insulation wire cores are twisted in opposite directions according to adjacent layers. The action force between the inner and outer layers can be offset when the cable is pulled.

[0054] In the embodiment, the conductor is composed of tinned copper wires, which effectively improves the use temperature of the cable and has excellent oxidation resistance.

[0055] In the embodiment, the gap between the insulation wire cores is filled with non-hygroscopic inorganic paper rope, which can significantly improve the flame-retardant performance of the cable and maintain the roundness requirement of the cable.

[0056] In the embodiment, the radiation cross-linked polyethylene inner insulation layer is resistant to high temperature and aging, halogen-free and low-smoke environmentally friendly, protects the insulation wire core from damage and prolongs the service life of the cable, and the radiation cross-linked halogen-free low-smoke polyolefin outer insulation layer has excellent mechanical properties and radiation resistance.

[0057] In the embodiment, a radiation cross-linked halogen-free low-smoke polyolefin sheath material is used, which forms a thermosetting material after radiation cross-linking, ensuring the service life and radiation resistance of the cable.

[0058] In the embodiment, the inner and outer insulation layers are processed by a double-layer co-extrusion process, which is efficient, low in energy consumption, avoids defects such as layering, wrinkling, delamination between the sheath layer and the insulation layer, and poor combination of the wire core and the insulation.

[0059] In the embodiment, the inner insulation layer, the outer insulation layer and the sheath layer in the production step are irradiation cross-linked halogen-free low smoke, and the insulation is not contacted with moisture in the irradiation cross-linking process, thereby reducing the probability of the electrical performance problem of the cable caused by the incorporation of moisture; the irradiation cross-linking is particularly suitable for the production of special cables, the insulation material is modified by high-energy electron beams, the original linear C-H bond is destroyed by high-energy rays, and then the molecular structure is recombined to form a random network molecular structure, thereby improving the mechanical physical properties and temperature resistance of the material, and the electrical performance is also improved to a certain extent; meanwhile, the material is irradiated by high-energy electron beams on the organic thermoplastic material to convert the linear polymer into a three-dimensional network cross-linked structure; that is, the thermoplastic is converted into a non-soluble and non-melting thermosetting material, thereby improving and enhancing the physical and mechanical properties, and the irradiation cross-linking method can avoid the destruction of the low smoke and halogen characteristics by chemical cross-linking.

[0060] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can be variously changed and modified. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A 1E cable for nuclear power plants, characterized in that, The insulating cable comprises at least one conductor, an outer wall of each conductor is extruded with a heterogeneous double-layer co-extruded insulation layer, the outer wall of the heterogeneous double-layer co-extruded insulation layer is wrapped with a wrapping tape to form an insulating cable core, the insulating cable core is arranged in a filling body, and the filling body is sequentially wrapped with two kinds of heterogeneous wrapping tapes, a shielding layer, an inner sheath layer, an armor layer and an outer sheath layer; the heterogeneous double-layer co-extruded insulation layer comprises an inner insulation layer and an outer insulation layer.

2. A 1E cable for nuclear power plant applications as defined in claim 1, characterized in that, The conductors are twisted by a conductive material.

3. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The twisting pitch is 16-20 times the outer diameter of the conductor.

4. A nuclear power plant 1E cable as claimed in claim 3, characterised in that, The twisting direction of the outermost layer is left, and the twisting directions of adjacent layers are opposite.

5. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The double-layer co-extruded heterogeneous insulation layer comprises an irradiation cross-linked polyethylene inner insulation layer and an irradiation cross-linked halogen-free low-smoke flame-retardant polyolefin outer insulation layer which are superimposed.

6. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The thickness ratio of the inner insulation layer to the outer insulation layer is 1:

3.

7. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The inner sheath layer and the outer sheath layer are extruded in different ways.

8. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The materials of the inner insulation layer and the outer insulation layer are different.

9. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The materials of the two kinds of heterogeneous wrapping tapes are different.

10. A nuclear power plant 1E cable as claimed in claim 1, characterised in that, The gaps between the insulating cable cores are filled with non-hygroscopic inorganic paper ropes.

Images