Large-current glass-metal sealing electrical penetration assembly of nuclear power reactor

Abstract

The invention belongs to the technical field of nuclear reaction safety, and particularly relates to a nuclear power reactor high-current glass-metal sealing electrical penetration assembly, which comprises a metal shell with two through ends and a metal pin arranged in the metal shell in a penetrating manner, and the metal pin is in sealing connection with the metal shell through sealing glass; the two ends of the metal pin are respectively provided with a cavity, internal threads for connection are arranged in the cavities, and the cavities at the two ends of the metal pin are not communicated. One end of the metal pin is in threaded connection with an adapter, and the adapter can be in tight conductive connection with the copper conductor. Through the arrangement of the adapter, the direct contact between the copper conductor and the metal pin is avoided, and the phenomenon that the connection part of the copper conductor and the Kovar pin is burnt out due to overlarge heat productivity in a rated short-circuit heat capacity test is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear reaction safety, and in particular relates to a high-current glass-metal sealed electrical penetration piece for a nuclear power reactor. Background Art

[0002] Electrical penetrations are special electrical equipment installed on the reactor containment for cables to pass through the containment. Under normal and various accident conditions, electrical penetrations should be able to ensure the integrity of the containment, prevent the leakage of radioactive materials, and maintain the continuity of electricity and signals in the containment. The main functional components of electrical penetrations include conductor components and cylinder components. The conductor components penetrate the entire cylinder component to achieve physical connection of various cables inside and outside the containment. While achieving electrical connection and signal transmission functions, they work together with the penetration cylinder component to achieve the integrity of the containment pressure boundary.

[0003] The conductor assembly of electrical penetrations is mainly composed of a metal shell, a metal conductor and a sealing material, wherein the types of sealing materials mainly include polymers, glass and ceramics. The metal shell and the metal conductor are sealed by the sealing material, so the selection of the sealing material determines the performance of the conductor assembly of the electrical penetration. Currently, polymer sealing materials are the most widely used in electrical penetrations.

[0004] Although polymer sealing materials can meet the strict standards of electrical penetrations in all aspects of performance, polymer materials are inevitably prone to aging phenomena such as embrittlement and creep during long-term operation and extended life operation. After aging, there is a risk of losing sealing and insulation functions in the event of high temperature, high humidity, or high radiation accidents. Using glass-metal sealing materials to replace polymer sealing materials used in electrical penetration conductor assemblies can improve the sealing performance of pressure boundaries under extreme working conditions and reduce the risk of radioactive leakage after an accident. Therefore, glass-metal sealed electrical penetration conductor assemblies have become a safer and more reliable choice.

[0005] The conductor assembly of the electrical penetration needs to meet the rated short-circuit heat capacity test. For the polymer sealed conductor assembly, its structure is that the whole copper conductor is forged by polymer material. The copper conductor connection structure is reliable, there is no bad contact point, and there is no obvious heat generation during the rated short-circuit heat capacity test. At the same time, as a good insulating material, polymer has good high temperature resistance and can withstand the heat generated during the test. Therefore, the polymer sealed conductor assembly can pass the test. For the glass-metal sealed conductor assembly, due to the immature technology of glass sealing metal copper, the mature glass sealing Kovar alloy technology is selected to ensure the high requirements of the electrical penetration for airtight performance. The metal stainless steel shell and the Kovar pin are glass-sealed as the joints at both ends of the conductor assembly. The copper conductor inside the conductor assembly is connected to the sealing assembly. Since the resistivity of Kovar is 25 to 30 times that of oxygen-free copper, and considering that the contact resistance is affected by factors such as contact method, contact area, and contact surface roughness during the actual connection process, the conductor assembly using conventional connection methods often burns out at the connection between the copper conductor and the Kovar pin due to excessive heat generation during the rated short-circuit heat capacity test.

[0006] Chinese patent application CN202210088324 discloses an electrical penetration component and a preparation method thereof, wherein the structure comprises an outer shell and a cylinder connected by glass sealing, and two guide needles are passed through the cylinder, wherein the first part of the guide needle is fixedly connected to the cylinder, and a certain gap is left between the second part of the guide needle and the cylinder.

[0007] This structure achieves good sealing through glass and reduces the stress of the sealed glass, avoiding cracks in the sealed glass due to stress concentration. However, since the guide pin (the guide pin is made of copper, equivalent to a copper conductor) is directly connected to the cylinder (the material used is Kovar metal, equivalent to a metal pin), there is still a possibility that the first part of the guide pin and the Kovar pin connection will burn out due to excessive heat generation during the rated short-circuit thermal capacity test. Summary of the invention

[0008] The object of the present invention is to provide a high-current glass-metal sealed electrical penetration for a nuclear power reactor. The adapter is set to avoid direct connection between the copper conductor and the metal pin, thereby avoiding the burning phenomenon at the connection between the copper conductor and the Kovar pin due to excessive heat generation during rated short-circuit thermal capacity measurement. The structure of the present invention is relatively simple, easy to process, and has high product quality consistency. The electrical penetration prepared with this structure solves the electrical performance defects of the conductor assembly after the sealing material is replaced. By using this structure, the sealing material of the conductor assembly of the electrical penetration is replaced from polymer to inorganic glass, which meets the various identification test requirements of the electrical penetration of the nuclear power reactor and improves the service life of the electrical penetration. In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is

[0009] A high-current glass-metal sealed electrical penetration piece for a nuclear power reactor comprises a metal shell with two ends passing through and a metal pin inserted into the metal shell, wherein the metal pin is sealed and connected to the metal shell through sealing glass; cavities are respectively arranged at both ends of the metal pin, the cavities at both ends of the metal pin are not connected, and a connecting thread structure is arranged in the cavity at at least one end of the metal pin; an adapter is threadedly connected to at least one end of the metal pin, and the adapter can be tightly conductively connected to a copper conductor.

[0010] Preferably, the thread depth of the adapter is less than or equal to the thread depth of the metal pin.

[0011] Preferably, a threaded structure is provided on the outer periphery of one end of the adapter, and a connecting socket is provided on the other end; the end with the threaded structure is threadedly connected to the metal pin, and the end with the connecting socket is provided for inserting a copper conductor, and the copper conductor is crimped and connected in the connecting socket.

[0012] Preferably, the end of the copper conductor is in complete contact with the bottom of the connecting socket, and the outer peripheral surface of the copper conductor and the end of the copper conductor located in the connecting socket are in conductive contact with the contact surface of the connecting socket.

[0013] Preferably, a separation wall for blocking communication is provided between the bottoms of the cavities opened at both ends of the metal pin.

[0014] Preferably, the metal shell is made of 06Cr19Ni10 stainless steel, the metal pin is made of 4J29 Kovar metal, and the adapter is made of red copper.

[0015] Preferably, the copper conductor is made of oxygen-free copper.

[0016] Preferably, a heat shrink tubing is provided on the periphery of the metal pin located on one side of the adapter and starting from the sealing glass side and the periphery of the adapter.

[0017] Preferably, the heat shrink tubing is nuclear power K1 grade.

[0018] Preferably, the electrical penetration member is capable of withstanding a short-circuit current peak of 50 kA for an application time of 0.3 s.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The present invention avoids direct contact between the copper conductor and the metal pin by providing an adapter, and avoids the burning phenomenon of the connection between the copper conductor and the Kovar pin due to excessive heat generation in the rated short-circuit thermal capacity test.

[0021] Through the threaded connection with the metal pin, during the rated short-circuit thermal capacity current test, the threaded connection between the metal pin and the adapter expands due to heat, forming a completely tight contact, reducing poor contact phenomena such as false connection.

[0022] The copper conductor and the adapter are connected by crimping to ensure the connection strength.

[0023] The metal pins and adapters are easy to process. During the sealing assembly, the metal pins, metal shell and glass only need to be placed in a packaging mold for high-temperature sealing, which makes the assembly simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the cross-sectional structure of the electrical penetration member of the present invention.

[0025] Figure 2 It is a schematic diagram of the structure of the metal pin in the present invention.

[0026] Figure 3 It is a schematic diagram of the structure of the transfer joint in the present invention.

[0027] Figure 4 It is a schematic diagram of the structure after the insulation layer is removed from one end of the copper conductor connected to the adapter in the present invention.

[0028] Figure 5 It is a schematic diagram of the sealing component structure in the present invention.

[0029] Wherein: metal shell 1, sealing glass 2, metal pin 3, cavity 31, isolation wall 32, adapter 4, heat shrink sleeve 5, copper conductor 6. DETAILED DESCRIPTION

[0030] The above technical solution is described in detail with reference to preferred embodiments and drawings. The directional words involved in the present invention, such as up, down, left, right, front, back, top, bottom, etc., are only used to assist understanding and do not limit the technical solution of the present invention.

[0031] The glass-to-metal sealed electrical penetration of the present invention is shown in Figure 1 , including a metal shell 1, a sealing glass 2, a metal pin 3, an adapter 4, a heat shrink tubing 5, and a copper conductor 6. Among them:

[0032] The metal shell 1 is a cylindrical structure with two ends penetrating the hollow part, and its material is 06Cr19Ni10 stainless steel.

[0033] The metal pin 3 is made of 4J29 Kovar alloy, and the cross-section along its length shows an I-shaped structure, see Figure 2A cavity 31 with a certain depth is respectively provided at both ends of the metal pin 3 along its length direction. The cavities 31 at both ends of the metal pin 3 are separated by a partition wall 32, so that the cavities 31 at both ends of the metal pin 3 are not connected. The partition wall 32 and the tube wall at the cavities at both ends of the metal pin 3 are an integral structure. A threaded structure is respectively provided in the cavities 31 at both ends of the metal pin 3, which is an internal thread in this embodiment.

[0034] The metal pin 3 is inserted into the metal shell 1, and both ends of the metal pin 3 extend out of the ends of the metal shell 1. The metal pin 3 and the metal shell 1 are sealed and fixed by the sealing glass 2 under high temperature conditions. The sealing glass 2 is located in the hollow part with a smaller inner diameter on one side of the step structure in the metal shell 1.

[0035] The gap between the metal pin 3 and the metal housing 1 is sealed by the sealing glass 2. A gap is retained between the metal housing 1 and the metal pin 3 on both sides of the sealing glass 2. The sealing glass 2 and the isolation wall in the metal pin 3 realize the overall sealing of the electrical penetration component to prevent the leakage of radiation substances from the electrical penetration component.

[0036] Adapter 4, made of copper, see Figure 3 , one end is a connection end 41 conductively connected to the metal pin 3, and the other end is a connection end 42 conductively connected to the copper conductor 6. A threaded structure is provided on the outer peripheral surface of the connection end 41, which is an external thread in this embodiment, and can be threadedly connected to the threaded structure of the cavity of the metal pin 3. The connection end 41 is threadedly connected to the cavity 31 at one end of the metal pin 3. The depth of the external thread of the connection end 41 of the adapter 4 should be less than or equal to the depth of the internal thread in the cavity 31 of the metal pin 3 to ensure that the adapter and the metal pin are threadedly connected tightly without looseness. The connection end 42 is provided with a connection socket 421 on the end face of the connection end 42 along the length direction of the adapter 4, and the bottom of the connection socket 421 is a conical structure.

[0037] A heat shrink tube 5 is provided on the outer periphery of the metal pin 3 on one side of the sealing glass 2 and the outer periphery of the adapter 4 connected thereto, so as to insulate the metal pin 3 and the outer periphery of the adapter 4 exposed outside the sealing glass 2. The material of the heat shrink tube 5 is nuclear power K1 grade.

[0038] The copper conductor 6 is made of oxygen-free copper and is a multi-stranded wire structure. An insulating layer is provided on the outside of the copper conductor 6. The copper conductor 6 generally adopts a multi-stranded wire structure with a diameter of φ30mm. The insulation layer is removed from one end of the copper conductor 6 connected to the adapter 4 to expose the multi-stranded wire structure. Figure 4The exposed length needs to be greater than the depth of the connection hole 421 to ensure that the connection end of the copper conductor 6 can be inserted into the bottom of the connection hole 421. The connection end of the copper conductor 6 is inserted into the connection hole 421 of the adapter 4, and the copper conductor 6 is crimped and fixed in the connection hole 421 by the crimping device, so as to achieve a conductive and tight connection between the copper conductor 6 and the adapter 4.

[0039] When assembling electrical penetration parts, the metal shell 1 and the metal pin 3 are first sintered at high temperature through the sealing glass 2 to form a sealing component. The sealing component is then subjected to performance testing, surface treatment, and gold plating processes in sequence. Figure 5 The sealing component structure shown.

[0040] Then the adapter is threadedly connected to the metal guide pin 3, and the copper conductor is crimped and connected to the connecting socket of the adapter.

[0041] The glass-metal sealed electrical penetration component of the present invention meets the conditions of withstanding a short-circuit current peak value of 50 kA and an application time of 0.3 s.

[0042] The glass-to-metal sealed electrical penetration of the present invention connects the copper conductor and the metal guide pin through an adapter, thereby avoiding the phenomenon that when the copper conductor is directly connected to the metal guide pin, the connection between the copper conductor and the Kovar pin is often burned out due to excessive heat generation in the rated short-circuit thermal capacity test.

[0043] The invention has a relatively simple structure, is easy to control in processing technology and has good product consistency.

Claims

1. A high current glass-metal sealed electrical penetration for a nuclear power reactor, characterized in that: It comprises a metal shell with two ends through and a metal pin inserted in the metal shell, wherein the metal pin is sealed and connected to the metal shell by sealing glass; cavities are respectively provided at both ends of the metal pin, the cavities at both ends of the metal pin are not connected, and a connecting thread structure is provided in the cavity at at least one end of the metal pin; an adapter is threadedly connected to at least one end of the metal pin, and the adapter can be tightly conductively connected to a copper conductor.

2. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 1, characterized in that: The thread depth of the adapter is less than or equal to the thread depth of the metal pin.

3. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 2, characterized in that: A threaded structure is provided on the outer periphery of one end of the adapter, and a connecting socket is provided on the other end; the end with the threaded structure is threadedly connected to the metal pin, and the end with the connecting socket is provided for inserting a copper conductor, and the copper conductor is crimped and connected in the connecting socket.

4. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 3, characterized in that: The end of the copper conductor is in full contact with the bottom of the connecting socket, and the outer peripheral surface of the copper conductor and the end located in the connecting socket are in conductive contact with the contact surface of the connecting socket.

5. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 1, characterized in that: An isolation wall for blocking communication is arranged between the bottoms of the cavities opened at both ends of the metal pin.

6. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 1, characterized in that: The metal shell is made of 06Cr19Ni10 stainless steel, the metal pin is made of 4J29 Kovar metal, and the adapter is made of red copper.

7. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 1, characterized in that: The copper conductor is made of oxygen-free copper.

8. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 1, characterized in that: A heat shrink tubing is provided on the outer periphery of the metal pin located on one side of the adapter and starting from the sealing glass side and the outer periphery of the adapter.

9. The nuclear power reactor high current glass-metal sealed electrical penetration according to claim 8, characterized in that: The heat shrink tubing is nuclear power K1 grade.

10. The nuclear power reactor high current glass-to-metal sealed electrical penetration according to any one of claims 1 to 9, characterized in that: The electrical penetration piece is capable of withstanding a short-circuit current peak of 50 kA and an application time of 0.3 s.

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