Nuclear power station cable end sealing structure and welding leak detection device for nuclear power station cable end sealing structure

Abstract

The invention relates to the technical field of sealing welding of cables, in particular to a nuclear power station cable end sealing structure and a welding leak detection device for the nuclear power station cable end sealing structure, the sealing structure comprises a cable assembly, a copper sheath, a metal clamping sleeve, a sleeve and a connector, the cable assembly comprises a copper corrugated pipe, an organic cable and an armored cable, the copper corrugated pipe is arranged at one end of the organic cable, and the other end of the organic cable is connected with the armored cable through the connector; the copper sheath is welded on the copper corrugated pipe; the sleeve is of a cylindrical cavity structure, one end of the sleeve is buckled on the cylindrical surface of the periphery of the copper sheath through the metal clamping sleeve, and the other end of the sleeve is buckled on the cylindrical surface of the connector through the metal clamping sleeve. According to the invention, the cable end of the nuclear power station can be effectively sealed in severe environments such as high temperature, high humidity and high radioactivity, and the problem caused by sealing by using a heat shrink tube is solved.

Description

Technical Field

[0001] The present application relates to the technical field of cable sealing welding, and in particular to a sealing structure of a cable end of a nuclear power plant and a welding leak detection device therefor. Background Art

[0002] The ex-core nuclear measurement system is an important nuclear measurement instrument system for measuring reactor power in nuclear power plants. The detector part of the system is installed around the reactor of the nuclear power plant to monitor the neutron flux level around the reactor in real time, provide the reactor protection system with the reactor power level and change cycle, and is used for nuclear power plant reactor nuclear power monitoring and accident shutdown protection; the detector of the ex-core nuclear measurement system transmits the weak signal generated by the detector to the outside of the containment through the integrated three-coaxial mineral armored cable welded to the detector and the four-coaxial special organic cable to transmit the signal, and the electrical penetration feedthrough line to transmit the weak signal generated by the detector to the outside of the containment.

[0003] The related cable connectors in the shell of the out-of-reactor nuclear measurement system should withstand the design benchmark accident conditions and the environmental conditions of the primary circuit main steam pipeline rupture and water loss accident. They can still work normally under high-temperature steam and post-accident conditions, and the use environment is relatively harsh. The integrated three-coaxial mineral armored cable, electrical penetration feedthrough and connector in the shell of the system are integrated into a full metal welding structure, so it can meet the requirements of its use environment. For the four-coaxial special cable, its internal electrical performance structure is that of an ordinary three-coaxial organic cable. The internal insulation layer of the cable insulates its inner core and inner shielding layer, and the external insulation insulates the inner shielding layer and the outer shielding layer, and finally wrapped with a flame-retardant organic outer sheath.

[0004] However, if it is to be used in such harsh environments, the outer sheath of the organic material is easily deformed by the impact of high-temperature steam and thus penetrated, causing the electrical performance of the cable to deteriorate and thus affecting the transmission of the signal; the four-coaxial special cable adds a layer of metal sheath that is resistant to high-temperature steam on the basis of the ordinary three-coaxial organic cable, and the cable end integrated connector realizes sealing in harsh environments; the metal sheath of the four-coaxial special cable is usually designed as a metal copper bellows structure, made of oxygen-free copper, and has excellent sealing performance. After the special cable end is integrated, on the one hand, it must meet the signal transmission function of the system, and on the other hand, the armored cable and electrical penetration feed-through line connected to it need to be fully sealed to ensure that the signal link is protected from steam erosion under high temperature and high pressure; therefore, the cable end integration requires higher sealing performance, and the sealed end needs to be leak-checked.

[0005] At present, the common sealing form of nuclear power plant cables and connector ends after integration is to directly use nuclear-grade heat shrink tubing for direct heat shrinkage, and heat shrink the outer copper corrugated tube of the cable, the male connector, and the female connector into a whole to ensure its sealing. However, due to the high heat and high radiation conditions in the containment, the heat shrink tubing will have a reduced service life due to rapid aging, thereby affecting the sealing effect. In addition, since the copper metal sheath is a corrugated structure, the heat shrink tubing usually has a thinner wall. It has an excellent sealing effect for smooth cylindrical structures, but it cannot fully and effectively fill the corrugated concave-convex structure during heat shrinkage, and it is easy to have loose bonding after long-term use, thereby reducing the sealing effect and affecting the performance of the equipment. In addition, after sealing with heat shrink tubing, it is impossible to effectively detect its sealing effect, and there is currently no leak detection tooling. Summary of the invention

[0006] The present application provides a nuclear power plant cable end sealing structure and a welding leak detection device therefor, which can achieve effective sealing of the cable end in harsh environments such as high temperature, high humidity, and high radioactivity.

[0007] In order to achieve the above-mentioned purpose, the present application provides a nuclear power plant cable end sealing structure, including a cable assembly, a copper sheath, a metal ferrule, a sleeve and a connector, wherein: the cable assembly includes a copper bellows, an organic cable and an armored cable, the copper bellows is arranged at one end of the organic cable, and the other end of the organic cable is connected to the armored cable through a connector; the copper sheath is welded on the copper bellows; the sleeve is a cylindrical cavity structure, one end of which is buckled on the cylindrical surface of the outer periphery of the copper sheath through a metal ferrule, and the other end is buckled on the cylindrical surface of the connector through a metal ferrule; the sleeve encloses the organic cable, the connector, the connection between the copper bellows and the organic cable, and the connection between the armored cable and the connector as a whole inside the cavity.

[0008] Furthermore, the copper sheath is a two-section cylinder with a groove structure arranged in the middle.

[0009] Furthermore, the connector includes a male connector and a female connector, one end of the male connector is connected to the organic cable, the other end is connected to one end of the female connector, and the other end of the female connector is connected to the armored cable.

[0010] Furthermore, the metal ferrule at the front end is fixedly arranged on the cylindrical surface of the copper sheath, and the metal ferrule at the rear end is fixedly arranged on the cylindrical surface of the connector female head.

[0011] In addition, the present application also provides a welding leak detection device for the sealing structure of the cable end of a nuclear power plant, including an intelligent refrigeration water tank, a high-frequency welding machine, an eddy current high-frequency welding ring, a spiral cooling structure and a cable fixing bracket, wherein: the cable assembly is fixed by the cable fixing bracket; the spiral cooling structure and the eddy current high-frequency welding ring are sequentially sleeved on the cable assembly and are concentric with the cable assembly; the high-frequency welding machine is connected to the eddy current high-frequency welding ring; the intelligent refrigeration water tank is connected to the water inlet of the spiral cooling structure through a water inlet pipe, and is connected to the water outlet of the spiral cooling structure through a return water pipe.

[0012] Furthermore, during welding, the copper sheath is straightened on the outside of the cable assembly and then passes through the eddy current high-frequency welding ring and the spiral cooling structure in sequence.

[0013] Furthermore, it also includes a sealing cavity, a sealing ring and a sealing plug, wherein: an air inlet is provided on the sealing cavity; the sealing ring is arranged at the front end of the sealing cavity, used for sealing between the copper sheath and the sealing cavity; the sealing plug is arranged at the rear end of the sealing cavity, used for sealing between the copper bellows and the sealing cavity.

[0014] Furthermore, the sealing ring is an O-ring; and the sealing plug is a conical silicone rubber sealing plug.

[0015] Furthermore, when checking for leaks, the welded copper sheath and cable assembly are passed through the sealing ring and the sealing plug in turn so that the whole is arranged inside the sealed cavity, and the welding point between the copper sheath and the copper bellows is exposed outside the sealed cavity, and air is inflated into the sealed cavity through the air inlet.

[0016] The present application provides a nuclear power plant cable end sealing structure and a welding leak detection device therefor, which have the following beneficial effects:

[0017] The present application can achieve effective sealing of the cable ends of nuclear power plants in harsh environments such as high temperature, high humidity, and high radioactivity, overcoming the problems caused by using heat shrink tubes for sealing, and also provides a corresponding welding leak detection device, overcoming the problems of traditional electric soldering irons with unconcentrated heating energy, slow heating speed, insufficient welding, and damage to internal organic cables, and can also detect the sealing effect to ensure the effectiveness and reliability of the sealing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0019] Figure 1 is a schematic diagram of a cable end sealing structure for a nuclear power plant provided according to an embodiment of the present application;

[0020] Figure 2 It is a schematic diagram of a welding device for a sealing structure of a cable end of a nuclear power plant provided in accordance with an embodiment of the present application;

[0021] Figure 3 It is a schematic diagram of a leakage detection device for a sealing structure of a cable end of a nuclear power plant provided according to an embodiment of the present application;

[0022] In the figure: 1-copper bellows, 2-organic cable, 3-armored cable, 4-copper sheath, 5-casing, 6-metal ferrule, 7-connector male head, 8-connector female head, 9-intelligent refrigeration water tank, 10-high frequency welding machine, 11-eddy current high frequency welding ring, 12-spiral cooling structure, 13-cable fixing bracket, 14-water inlet pipe, 15-return water pipe, 16-sealing cavity, 17-sealing ring, 18-sealing plug, 19-air inlet, 20-weld. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0026] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0027] In addition, the term "plurality" shall mean two or more.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] like Figure 1 As shown, the present application provides a nuclear power plant cable end sealing structure, including a cable assembly, a copper sheath 4, a metal ferrule 6, a sleeve 5 and a connector, wherein: the cable assembly includes a copper bellows 1, an organic cable 2 and an armored cable 3, the copper bellows 1 is arranged at one end of the organic cable 2, and the other end of the organic cable 2 is connected to the armored cable 3 through a connector; the copper sheath 4 is welded on the copper bellows 1; the sleeve 5 is a cylindrical cavity structure, one end of which is buckled on the cylindrical surface of the outer periphery of the copper sheath 4 through a metal ferrule 6, and the other end is buckled on the cylindrical surface of the connector through a metal ferrule 6; the sleeve 5 encloses the organic cable 2, the connector, the connection between the copper bellows 1 and the organic cable 2, and the connection between the armored cable 3 and the connector as a whole inside the cavity.

[0030] Specifically, the nuclear power plant cable end sealing structure provided in the embodiment of the present application is mainly used for sealing the end structure of the four-coaxial special cable in the nuclear power plant, ensuring that it has good signal transmission function and is protected from corrosion by high-temperature and high-pressure steam. Among them, the entire cable assembly is composed of a copper bellows 1 at the front end, an organic cable 2 in the middle section, and an armored cable 3 at the rear end; the embodiment of the present application mainly utilizes the copper sheath 4 to weld with the copper bellows 1, and utilizes the sleeve 5 to seal the organic cable 2 and the connector structure, thereby achieving the sealing of the end structure of the entire cable assembly. The sleeve 5 is made of metal material and has a cylindrical cavity structure as a whole. The interior is used to place the organic cable 2 and the connector to provide a sealed space for them; the front end of the sleeve 5 is fixed to the copper sheath 4 by a metal ferrule 6, and the copper sheath 4 is welded and fixed to the copper corrugated tube 1 as a whole, thereby realizing the metal sealing of the front end of the sleeve 5; the rear end of the sleeve 5 is fixed to the connector by a metal ferrule 6, and the connector fork is connected to the armored cable 3, thereby realizing the metal sealing of the rear end of the sleeve 5; the organic cable 2 and the connector are arranged in the internal sealed chamber space through the sleeve 5, and the copper sheath 4 and the metal ferrule 6 are used to realize the sealing of the two ends of the sleeve 5, thereby realizing the overall effective sealing of the cable assembly end structure.

[0031] Furthermore, the copper sheath 4 is a two-stage cylinder with a groove structure in the middle. The copper sheath 4 is mainly used for welding with the copper bellows 1 to ensure the sealing effect of the front end of the sleeve 5. In the embodiment of the present application, the copper sheath 4 is preferably designed with a two-stage structure, wherein the middle part of the copper sheath 4 is provided with a groove structure, which can effectively slow down the conduction speed of the temperature during welding and avoid the temperature conduction being too fast to affect the heat concentration at the welding point.

[0032] Further, the connector includes a male connector 7 and a female connector 8, one end of the male connector 7 is connected to the organic cable 2, and the other end is connected to one end of the female connector 8, and the other end of the female connector 8 is connected to the armored cable 3. The connector is mainly used for connecting the organic cable 2 and the armored cable 3, and is also used for signal transmission, so the connector is disposed as a whole in the closed cavity inside the sleeve 5 to ensure its sealing effect.

[0033] Furthermore, the front metal ferrule 6 is fixedly arranged on the cylindrical surface of the copper sheath 4, and the rear metal ferrule 6 is fixedly arranged on the cylindrical surface of the connector female head 8. The metal ferrule 6 is arranged at the front and rear ends of the sleeve 5, and is used for fixing and sealing the front and rear ends of the sleeve 5, respectively, to ensure the sealing effect of the internal cavity of the sleeve 5.

[0034] In addition, if Figure 2 As shown, the present application also provides a welding leak detection device for the sealing structure of the cable end of a nuclear power plant, including an intelligent refrigeration water tank 9, a high-frequency welding machine 10, an eddy current high-frequency welding ring 11, a spiral cooling structure 12 and a cable fixing bracket 13, wherein: the cable assembly is fixed by the cable fixing bracket 13; the spiral cooling structure 12 and the eddy current high-frequency welding ring 11 are sequentially sleeved on the cable assembly and are concentric with the cable assembly; the high-frequency welding machine 10 is connected to the eddy current high-frequency welding ring 11; the intelligent refrigeration water tank 9 is connected to the water inlet of the spiral cooling structure 12 through the water inlet pipe 14, and is connected to the water outlet of the spiral cooling structure 12 through the return water pipe 15.

[0035] Furthermore, during welding, the copper sheath 4 is straightened on the outside of the cable assembly and then passes through the eddy current high-frequency welding ring 11 and the spiral cooling structure 12 in sequence.

[0036] Specifically, the welding leak detection device for the sealing structure of the cable end of a nuclear power plant provided in the embodiment of the present application is mainly used for welding between the copper sheath 4 and the copper bellows 1, and leak detection of the effect after welding. Among them, the welding device adopts a high-frequency welding method, and an intelligent refrigeration water tank 9 and a spiral cooling structure 12 are set to automatically cool the parts outside the welding point to protect the cable. When the copper sheath 4 and the copper bellows 1 are welded using the embodiment of the present application, the copper sheath 4 is firstly put on the outer side of the cable assembly to be welded, and after a straightening treatment, it is passed through the eddy current high-frequency welding ring 11 and the spiral cooling structure 12 in turn, and the direction of the cable assembly is adjusted with a cable fixing bracket 13, so that the cable assembly is concentric with the eddy current high-frequency welding ring 11 and the spiral cooling structure 12; then, an intelligent refrigeration water tank 9 is configured, and the intelligent refrigeration water tank 9 can be set with a high-temperature start-up water circulation function and perform temperature monitoring on the pipeline water; the high-frequency welding machine 10 is started to generate a local concentrated high temperature inside the eddy current high-frequency welding ring 11, and a special welding wire is used to evenly coat the cable assembly. It is applied to the gap between the copper sheath 4 and the copper bellows 1 until the welding surface groove is filled, and the welding surface solder is round and full. Since the high welding temperature may affect the internal performance of the cable due to excessive heat transfer of the copper sheath 4, during the welding process, when the intelligent refrigeration water tank 9 detects the water temperature setting threshold in the pipeline, it will trigger the water circulation. The water inside the intelligent refrigeration water tank 9 flows into the spiral cooling structure 12 through the water inlet pipe 14. The cooling structure adopts a spiral form, which can increase the cooling efficiency and take away the heat outside the welding point in time to protect the inside of the cable from burns. The subsequent cooling water will flow back to the water tank through the return pipe 15 to achieve circulating cooling.

[0037] Further, such as Figure 3 As shown, it also includes a sealing cavity 16, a sealing ring 17 and a sealing plug 18, wherein: an air inlet 19 is provided on the sealing cavity 16; the sealing ring 17 is provided at the front end of the sealing cavity 16, and is used for sealing between the copper sheath 4 and the sealing cavity 16; the sealing plug 18 is provided at the rear end of the sealing cavity 16, and is used for sealing between the copper bellows 1 and the sealing cavity 16.

[0038] Furthermore, the sealing ring 17 is an O-type sealing ring; and the sealing plug 18 is a conical silicone rubber sealing plug.

[0039] Furthermore, when checking for leaks, the welded copper sheath 4 and cable assembly are passed through the sealing ring 17 and the sealing plug 18 in turn, so that the whole is arranged inside the sealed cavity 16, and the welding point between the copper sheath 4 and the copper bellows 1 is exposed outside the sealed cavity 16, and air is inflated into the sealed cavity 16 through the air inlet 19.

[0040] Specifically, after the copper sheath 4 and the copper bellows 1 are welded, in order to ensure the reliability of the welding and the subsequent sealing performance of the entire section, the embodiment of the present application can also detect the sealing of the welding of the copper sheath 4. The leak detection device as a whole adopts a sealed cavity 16 structure, and a front sealing end and a rear sealing end are arranged inside the sealed cavity 16. When leak detection is performed, the welded copper sheath 4 and the cable assembly are inserted into the sealed cavity 16 as a whole, wherein the copper sheath 4 is placed at the front sealing end, so an O-ring 17 is adopted for sealing, and the copper bellows 1 is placed at the rear sealing end, so a customized conical silicone rubber sealing plug 18 is adopted for sealing. The sealing plug 18 can produce axial and radial deformation under the extrusion of the end face sealing end, and fill the concave part of the copper bellows 1 to achieve a sealing effect, thereby realizing the front and rear sealing of the sealed cavity 16; at this time, the welding part between the copper sheath 4 and the copper bellows 1 is exposed outside the sealed cavity 16, and the sealed cavity 16 is inflated and pressurized through the air inlet 19, and the weld 20 is leak-detected with a leak detection liquid, so as to judge the welding effect and reliability of the copper sheath 4.

[0041] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. 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 cable end sealing structure for a nuclear power plant, characterized in that: It includes cable assemblies, copper sheaths, metal ferrules, sleeves and connectors, including: The cable assembly comprises a copper corrugated tube, an organic cable and an armored cable, wherein the copper corrugated tube is arranged at one end of the organic cable, and the other end of the organic cable is connected to the armored cable through a connector; The copper sheath is welded on the copper bellows; The sleeve is a cylindrical cavity structure, one end of which is buckled on the cylindrical surface of the outer periphery of the copper sleeve through the metal ferrule, and the other end is buckled on the cylindrical surface of the connector through the metal ferrule; The sleeve integrally encloses the organic cable, the connector, the connection between the copper corrugated tube and the organic cable, and the connection between the armored cable and the connector in the cavity.

2. The nuclear power plant cable end sealing structure according to claim 1, characterized in that: The copper sheath is a two-section cylinder with a groove structure arranged in the middle.

3. The cable end sealing structure for a nuclear power plant according to claim 2, characterized in that: The connector includes a male connector and a female connector, one end of the male connector is connected to the organic cable, and the other end is connected to one end of the female connector, and the other end of the female connector is connected to the armored cable.

4. The cable end sealing structure for a nuclear power plant according to claim 3, characterized in that: The metal ferrule at the front end is fixedly arranged on the cylindrical surface of the copper sheath, and the metal ferrule at the rear end is fixedly arranged on the cylindrical surface of the connector female head.

5. A welding leak detection device for the sealing structure of the cable end of a nuclear power plant according to claim 4, characterized in that: It includes intelligent cooling water tank, high frequency welding machine, eddy current high frequency welding ring, spiral cooling structure and cable fixing bracket, among which: The cable assembly is fixed by a cable fixing bracket; The spiral cooling structure and the eddy current high-frequency welding ring are sequentially sleeved on the cable assembly and are concentric with the cable assembly; The high-frequency welding machine is connected to the eddy-current high-frequency welding ring; The intelligent refrigeration water tank is connected to the water inlet of the spiral cooling structure through a water inlet pipe, and is connected to the water outlet of the spiral cooling structure through a water return pipe.

6. The welding leak detection device according to claim 5, characterized in that: During welding, the copper sheath is straightened on the outside of the cable assembly and then passes through the eddy current high-frequency welding ring and the spiral cooling structure in sequence.

7. The welding leak detection device according to claim 6, characterized in that: It also includes a sealing cavity, a sealing ring and a sealing plug, wherein: The sealed cavity is provided with an air inlet; The sealing ring is arranged at the front end of the sealing cavity and is used for sealing between the copper sheath and the sealing cavity; The sealing plug is arranged at the rear end of the sealing cavity and is used for sealing between the copper bellows and the sealing cavity.

8. The welding leak detection device according to claim 7, characterized in that: The sealing ring is an O-type sealing ring; the sealing plug is a conical silicone rubber sealing plug.

9. The welding leak detection device according to claim 8, characterized in that: When checking for leaks, the welded copper sheath and the cable assembly are passed through the sealing ring and the sealing plug in turn so that they are arranged as a whole inside the sealed cavity, and the welding point between the copper sheath and the copper bellows is exposed outside the sealed cavity, and air is inflated into the sealed cavity through the air inlet.

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