Optical fiber transmission assembly for underwater laser welding of nuclear power station reactor

Abstract

The invention discloses an optical fiber transmission assembly for underwater laser welding of a nuclear power station reactor, and relates to the technical field of nuclear power station equipment maintenance. Comprising an optical fiber output assembly with an optical fiber connector at one end, a laser optical fiber with one end welded with the end part of the optical fiber connector, and a radiation-resistant composite structure radiation-resistant protective sleeve which sleeves the outer side of the laser optical fiber and is provided with a sealing connector close to the end part of the optical fiber output assembly, the connector is arranged outside the optical fiber connector in a sleeving mode and used for being connected with the sealing connector in a sealed mode, the annular elastic sealing piece is arranged on the optical fiber connector in a sleeving mode and located in the connector, and the waterproof sealant is filled in an annular gap between the end, away from the sealing connector, of the connector and the optical fiber connector. Wherein the connector in a state of being connected with the sealing joint can apply an axial compression load to the annular elastic sealing element, so that the annular elastic sealing element is forced to elastically deform and cling to the outer surface of the optical fiber joint to form sealing with the inner surface of the connector. High-radiation protection and high-water-pressure sealing can be achieved.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant equipment maintenance technology, and in particular to an optical fiber transmission component for underwater laser welding of nuclear power plant reactors. Background Technology

[0002] Nuclear power plant reactor internal components are subjected to extreme environments of high radiation and high water pressure for extended periods, making them prone to defects that require underwater welding repair. While underwater laser welding technology is suitable for confined spaces, its core beam transmission components (fiber optics and QBH output devices) face severe challenges in this environment. High-energy radiation degrades the performance of quartz optical fibers, leading to increased optical loss, material aging, and even breakage. Simultaneously, the high water pressure and potential water molecule infiltration in deep water environments further impact laser transmission quality and equipment lifespan.

[0003] Existing underwater welding technologies mostly employ sealed chamber solutions with inert gas drainage or resist water flow disturbance through mechanical structures, but none of them are specifically designed for nuclear radiation environments. Summary of the Invention

[0004] The purpose of this invention is to provide an optical fiber transmission assembly for underwater laser welding of nuclear power plant reactors, so as to solve the problems existing in the prior art and achieve high radiation protection and high water pressure sealing.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides an optical fiber transmission assembly for underwater laser welding of nuclear power plant reactors, comprising: an optical fiber output assembly having an optical fiber connector at one end; a laser optical fiber having one end fused to the end of the optical fiber connector; a radiation-resistant protective sleeve, which is a radiation-resistant composite structure, fitted onto the outside of the laser optical fiber; and a sealing connector provided at the end of the radiation-resistant protective sleeve near the end of the optical fiber output assembly; a connector fitted onto the outside of the optical fiber connector and used for sealing connection with the sealing connector; an annular elastic seal fitted onto the optical fiber connector and located inside the connector; the connector, in the state of connection with the sealing connector, can apply an axial compressive load to the annular elastic seal, forcing the annular elastic seal to undergo elastic deformation and tightly adhere to the outer surface of the optical fiber connector and the inner surface of the connector; and a waterproof sealant filling the circumferential gap between the end of the connector away from the sealing connector and the optical fiber connector.

[0006] Preferably, it further includes a contour-following protective clamp; the contour-following protective clamp includes at least two combinable clamp bodies; each clamp body, after being combinated, has a first limiting cavity, a connecting cavity, and a second limiting cavity arranged sequentially in its internal cavity; the first limiting cavity can accommodate the integral connection structure of the connector and the sealing joint; the second limiting cavity can accommodate the external protrusion structure on the optical fiber output assembly; the inner diameter of both the first limiting cavity and the second limiting cavity is different from that of the connecting cavity.

[0007] Preferably, the sealing joint has a limiting part and an external thread section at one end near the connector, the external thread section being fixedly connected to the limiting part; the internal thread hole of the connector is threadedly connected to the external thread section; and a sealing rubber gasket is fitted on the external thread section.

[0008] Preferably, the radiation-resistant protective sleeve includes an inner metal protective tube and an outer radiation-resistant polymer protective layer; the outer radiation-resistant polymer protective layer is tightly fitted to the inner metal protective tube, and the inner metal protective tube has a flexible corrugated tubular structure.

[0009] Preferably, each of the clamps is fixedly connected by a plurality of fasteners, the fasteners being inserted into the corresponding connecting portions of the clamps.

[0010] Preferably, the laser fiber is a step-index fiber with a fluorine-doped silica cladding and a pure silicon core.

[0011] Preferably, the connector is a stainless steel waterproof and explosion-proof sealing gland with internal threads.

[0012] Preferably, the material of the annular elastic seal is EPDM rubber.

[0013] Preferably, the fastener includes a bolt and a nut, wherein the bolt passes through the connecting portion of the clamp and is threadedly connected to the nut.

[0014] Preferably, the inner metal protective tube is a stainless steel corrugated tube; the outer radiation-resistant polymer protective layer is an EPDM heat shrink tubing.

[0015] The present invention achieves the following technical effects compared to the prior art: The fiber optic transmission assembly for underwater laser welding in nuclear power plant reactors provided by this invention employs a radiation-resistant protective sleeve. Its radiation-resistant composite structure shields against high-energy radiation, preventing increased optical loss, aging, or breakage of the laser fiber. The connector and sealing joint work together, forcing the annular elastic seal to deform under pressure and tightly adhere to the fiber optic connector and the inner wall of the connector, forming a mechanical seal to block high-pressure water seepage. Waterproof sealant fills the circumferential gaps, providing secondary protection. Through multi-dimensional synergy of radiation shielding, mechanical compression, and gap filling, the components solve the existing problems of lack of nuclear radiation compatibility and deep-water sealing failure, ensuring stable transmission and long-life operation of the assembly in extreme environments. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the optical fiber transmission assembly for underwater laser welding of nuclear power plant reactors provided by the present invention. Figure 2 This is a schematic diagram of the optical fiber output component in the optical fiber transmission assembly for underwater laser welding of nuclear power plant reactors provided by the present invention.

[0018] In the diagram: 1-Outer radiation-resistant polymer protective layer; 2-Inner metal protective tube; 3-Sealing rubber gasket; 4-Laser fiber optic cable; 5-Bolt; 6-Contouring protective clamp; 7-Annular elastic sealant; 8-Connector; 9-Waterproof sealant; 10-Fiber optic output assembly; 11-Nut; 12-Sealing joint; 13-First limiting cavity; 14-Connecting cavity; 15-Second limiting cavity. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide an optical fiber transmission assembly for underwater laser welding of nuclear power plant reactors, in order to solve the problems existing in the prior art and achieve high radiation protection and high water pressure sealing.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 This embodiment provides an optical fiber transmission component for underwater laser welding of nuclear power plant reactors, such as... Figures 1-2 As shown, it includes: The fiber optic output assembly 10 has a fiber optic connector at one end. Laser fiber 4, one end of which is fused to the end of the fiber optic connector; The radiation-resistant protective sleeve is a radiation-resistant composite structure and is sleeved on the outside of the laser fiber 4; and the end of the radiation-resistant protective sleeve near the fiber output assembly 10 is provided with a sealing joint 12. Connector 8 is fitted over the fiber optic connector and is used for a sealed connection with sealing connector 12; The annular elastic seal 7 is fitted onto the fiber optic connector and located inside the connector 8. When connected to the sealing connector 12, the connector 8 can apply an axial compressive load to the annular elastic seal 7, forcing the annular elastic seal 7 to undergo elastic deformation and tightly adhere to the outer surface of the fiber optic connector and the inner surface of the connector 8. Waterproof sealant 9 is filled in the circumferential gap between the end of connector 8 away from sealing connector 12 and the fiber optic connector.

[0023] By employing a radiation-resistant protective sleeve, the high-energy radiation is shielded by its radiation-resistant composite structure, preventing increased optical loss, aging, or breakage of the laser fiber 4. The connector 8 and the sealing joint 12 cooperate to force the annular elastic seal 7 to deform under pressure and fit tightly against the inner wall of the fiber optic connector and the connector 8, forming a mechanical seal to block the high-pressure water seepage channel. The waterproof sealant 9 fills the circumferential gap to form secondary protection. Through the multi-dimensional synergy of radiation shielding, mechanical compression, and gap filling, the components solve the existing problems of lack of nuclear radiation compatibility and deep-water sealing failure, ensuring stable transmission and long-life operation of the components in extreme environments.

[0024] The following are the settings instructions for the fiber optic output component 10: Specifically, the fiber optic output component 10, or Quartz Block Head (QBH), is a quartz post for fiber optic splicing, combining a fiber end cap and mechanical encapsulation. Its function is to expand the beam of the output fiber, reducing the optical power density and thus protecting the fiber end face from damage. The mechanical encapsulation provides protection for the fiber core, damage monitoring, and external cooling, ensuring stable laser transmission between the fiber and the laser head.

[0025] The following are the settings instructions for laser fiber 4: In the optional schemes of this embodiment, the laser fiber 4 is preferably a step-index fiber with a fluorine-doped silica cladding and a pure silicon core.

[0026] Specifically, the fiber must be at least 30 meters long and must be inserted into deep water for welding. This type of optical fiber was chosen for its excellent radiation resistance and low refractive index. Fluorine doping can significantly reduce the refractive index of the quartz glass while avoiding increased fiber substrate loss, making it particularly suitable for underwater laser welding repair operations in nuclear power plant reactors.

[0027] The following are the relevant instructions regarding the installation of radiation protection sleeves: Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1 As shown, the radiation protection sleeve includes an inner metal protective tube 2 and an outer radiation-resistant polymer protective layer 1; the outer radiation-resistant polymer protective layer 1 is tightly fitted with the inner metal protective tube 2, and the inner metal protective tube 2 is a flexible corrugated tubular structure.

[0028] In the optional schemes of this embodiment, it is more preferred that the inner metal protective tube 2 is a stainless steel corrugated tube; and the outer radiation-resistant polymer protective layer 1 is an EPDM heat shrink tubing.

[0029] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1 As shown, the sealing joint 12 is provided with a limiting part and an external thread section at one end near the connector 8, and the external thread section is fixedly connected to the limiting part; the internal thread hole of the connector 8 is threadedly connected to the external thread section; and a sealing rubber gasket 3 is sleeved on the external thread section.

[0030] Specifically, the sealing rubber gasket 3 is located near the limiting part of the external thread section of the sealing joint 12 at the end of the radiation protection sleeve, and the material is also EPDM rubber.

[0031] The following are the settings instructions for connector 8: In the optional solutions of this embodiment, the connector 8 is preferably a stainless steel waterproof and explosion-proof sealing gland with internal threads.

[0032] Specifically, the gland uses an internally threaded stainless steel waterproof and explosion-proof sealing gland FT25-M32F-SS, with a thread size of M32×1.5, a thread length of 12.5mm, and a compatible diameter of 18~25mm. Its internal annular elastic seal 7 is made of EPDM rubber with good radiation resistance.

[0033] The following are the relevant specifications for the annular elastic seal 7: In the optional solutions of this embodiment, the material of the annular elastic seal 7 is preferably EPDM rubber.

[0034] The following are the settings instructions for waterproof sealant 9: Specifically, waterproof sealant 9 is a waterproof gel.

[0035] The following are the settings instructions for the contour protection fixture 6: Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1 As shown, it also includes a contour-following protective clamp 6; the contour-following protective clamp 6 includes at least two combinable clamp bodies; the internal cavity of each clamp body after being combinated has a first limiting cavity 13, a connecting cavity 14 and a second limiting cavity 15 arranged sequentially; the first limiting cavity 13 can accommodate the overall connection structure of the connector 8 and the sealing connector 12; the second limiting cavity 15 can accommodate the external protrusion structure on the optical fiber output assembly 10; the inner diameter of the first limiting cavity 13 and the second limiting cavity 15 is different from that of the connecting cavity 14.

[0036] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1 As shown, the clamps are fixedly connected by multiple fasteners, which are inserted into the corresponding connecting parts of the clamps.

[0037] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1 As shown, the fasteners include bolt 5 and nut 11. Bolt 5 passes through the connecting part of the clamp body and is threadedly connected to nut 11. Bolt 5 and nut 11 are standard parts used to fix each clamp body to form a contour-following protective clamp 6.

[0038] Specifically, the contour-following protective clamp 6 is made of stainless steel, and its internal cavity matches the external shape of the sealed structure, which can effectively protect the internal waterproof structure from loosening during repeated movement and pulling of the optical fiber.

[0039] Regarding other related settings: Specifically, the fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors provided in this embodiment, with its unique fiber optic protective sleeve design, sealed structure design, and enhanced dynamic stability during the welding process, has higher reliability and adaptability in complex underwater environments. It is particularly suitable for application scenarios that require high radiation protection and dynamic stability and have structural size limitations.

[0040] Specifically, multiple sealing measures (gland head, rubber ring (annular elastic seal 7, sealing rubber gasket 3), and waterproof gel) are used to ensure that water does not seep into the optical fiber under high water pressure.

[0041] Specifically, the design of the contour-following protective clamp 6 effectively solves the problem of sealing structure failure caused by dynamic tensile force, and significantly improves the long-term reliability of the device.

[0042] Specifically, the fiber optic sheath (i.e., radiation-resistant protective sheath) is a composite structure of stainless steel corrugated pipe and EPDM rubber, which can meet the flexibility requirements of underwater welding of optical fibers and the requirements of use in high radiation dose environments. The outer layer of EPDM rubber also improves the wear resistance of the protective sheath and facilitates cleaning after use.

[0043] Specifically, regarding the instructions for use: During the assembly of the sealing structure, EPDM heat shrink tubing is first fitted onto a stainless steel corrugated pipe and heated with a hot air gun to ensure a tight seal, forming an anti-radiation protective sleeve. Before the laser fiber 4 and the fiber output assembly 10 are fused, the anti-radiation protective sleeve is fitted onto the laser fiber 4. Then, an annular elastic seal 7 is placed inside the end of the anti-radiation protective sleeve, ensuring its outer surface is tightly fitted against the inner surface of the external thread at the end of the anti-radiation protective sleeve. Simultaneously, a sealing rubber gasket 3 is placed at the bottom of the external thread at the end of the anti-radiation protective sleeve.

[0044] Next, connector 8 is inserted from the bottom of the fiber optic output assembly 10. At this point, the laser fiber 4 is fused with the fiber inside the fiber optic output assembly 10. After cooling, the internal thread of connector 8 engages with the external thread of the radiation-resistant protective sleeve end and is tightened. When connector 8 is tightened, the annular elastic seal 7 deforms elastically under pressure, tightly fitting against the surface of the fiber optic output assembly 10 and the inner wall of connector 8, forming a mechanical seal. Simultaneously, the sealing rubber gasket 3 also deforms elastically due to the pressure of the tightened threads, forming a seal. Finally, waterproof gel is applied to the top of connector 8 and allowed to dry. This sealing structure effectively prevents water from the reactor from seeping into the fiber optic cable through the connection.

[0045] After assembly, the contoured protective clamps 6 are installed on both sides of the sealed structure, respectively, and clipped onto the top of the connector 8 and the end of the radiation-resistant protective sleeve, serving as a limiting device. The contoured protective clamps 6 are fixed by bolts 5 and nuts 11, ensuring that they fit tightly against the outside of the sealed structure. This ensures that repeated movement of the optical fiber during welding will not cause the sealed structure to be stretched and loosened, thus preventing the waterproof structure from failing.

[0046] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An optical fiber transmission assembly for underwater laser welding of nuclear power plant reactors, characterized in that: include: An optical fiber output assembly, one end of which has an optical fiber connector; A laser fiber, one end of which is fused to the end of the fiber optic connector; A radiation-resistant protective sleeve, which is a radiation-resistant composite structure, is fitted onto the outside of the laser fiber; and the end of the radiation-resistant protective sleeve near the fiber output assembly is provided with a sealing joint. A connector is fitted over the outside of the optical fiber connector and is used for a sealed connection with the sealing connector; An annular elastic seal is fitted onto the optical fiber connector and located inside the connector. When connected to the sealing connector, the connector can apply an axial compressive load to the annular elastic seal, forcing the annular elastic seal to undergo elastic deformation and fit tightly against the outer surface of the optical fiber connector and the inner surface of the connector. A waterproof sealant is applied to the circumferential gap between the end of the connector furthest from the sealing joint and the fiber optic connector.

2. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 1, characterized in that: It also includes contour-following protective clamps; The contour-following protective clamp includes at least two combinable clamp bodies; each clamp body, after being combinated, has a first limiting cavity, a connecting cavity, and a second limiting cavity arranged sequentially in its internal cavity; The first limiting cavity can accommodate the integral connection structure of the connector and the sealing joint; the second limiting cavity can accommodate the external protrusion structure on the optical fiber output assembly; the inner diameter of both the first limiting cavity and the second limiting cavity is different from that of the connecting cavity.

3. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 1, characterized in that: The sealing joint is provided with a limiting part and an external thread section at one end near the connector, and the external thread section is fixedly connected to the limiting part. The internal threaded hole of the connector is threaded onto the external threaded section; and a sealing rubber gasket is fitted onto the external threaded section.

4. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 1, characterized in that: The radiation-resistant protective sleeve includes an inner metal protective tube and an outer radiation-resistant polymer protective layer; the outer radiation-resistant polymer protective layer is tightly fitted to the inner metal protective tube, and the inner metal protective tube has a flexible corrugated tubular structure.

5. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 2, characterized in that: Each of the clamps is fixedly connected by a plurality of fasteners, which are inserted into the corresponding connecting parts of the clamps.

6. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 1, characterized in that: The laser fiber is a step-index fiber with a fluorine-doped silica cladding and a pure silicon core.

7. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 1, characterized in that: The connector is a stainless steel waterproof and explosion-proof sealing gland with internal threads.

8. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 1, characterized in that: The material of the annular elastic seal is EPDM rubber.

9. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 5, characterized in that: The fastener includes a bolt and a nut, the bolt being threaded onto the nut after passing through the connecting portion of the clamp.

10. The fiber optic transmission assembly for underwater laser welding of nuclear power plant reactors according to claim 4, characterized in that: The inner metal protective tube is a stainless steel corrugated pipe; the outer radiation-resistant polymer protective layer is an EPDM heat shrink tubing.

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