Primary neutron source rod mounting structure and method of mounting

Abstract

The application relates to the technical field of nuclear power plants, in particular to a primary neutron source rod mounting structure and a mounting method. The primary neutron source rod mounting structure comprises a connecting plate, a connecting plate rib is fixedly arranged on the connecting plate, and a mounting hole is arranged on the upper end surface of the connecting plate rib; a primary neutron source rod body is inserted into the mounting hole, the primary neutron source rod body comprises a californium-252 neutron source and a cladding tube, the californium-252 neutron source is arranged in the cladding tube; and a fixed connection assembly is arranged between the primary neutron source rod body and the upper end surface of the connecting plate and used for fixing the primary neutron source rod body on the upper end surface of the connecting plate. The application simplifies the installation operation process of the primary neutron source rod, shortens the operation time and the radioactive exposure time of personnel, and reduces the risk of introduction of foreign matters.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear power plants, in particular to a primary neutron source rod mounting structure and a mounting method. BACKGROUND

[0002] The primary neutron source used for starting up the RFA-2 type fuel assembly is used as the fuel of the nuclear reaction. The primary neutron source is made into a primary neutron source rod, and the primary neutron source rod is mounted in a specified connecting hole on a connecting plate of a primary neutron source assembly. During assembly, the fuel assembly and the primary neutron source assembly need to be hoisted for multiple times, and in addition to the normal required tools, positioning funnels, source rod protection sleeves, auxiliary support rods, neutron source connecting pieces, neutron source positioning plates, positioning pins, absorbent cotton, multifunctional toolboxes, torque wrenches, lubricating grease, magnifying glasses, guide combs, rainproof cloth and the like are also used.

[0003] The operation process is as follows: first, the primary neutron source assembly without the primary neutron source rod is hoisted out from the fuel assembly to be inserted, the primary neutron source rod containing californium-252 is hoisted and inserted into the guide pipe reserved in the fuel assembly and fixed, and then the primary neutron source assembly without the primary neutron source rod is hoisted and inserted back into the fuel assembly containing the primary neutron source rod. The upper end plug of the primary neutron source rod is inserted into the connecting hole of the connecting plate of the primary neutron source assembly, a locking nut is installed and flattened. This installation has the following problems: first, the operation time is long, and 1-2 or more operation rehearsals are required before installation, and the entire time is about 3-5 days; second, the personnel exposure time to radioactive irradiation is long, and the personnel dose is increased; and third, many tools are brought into the fuel plant for operation, and there is a risk of introducing foreign objects or tools.

[0004] Therefore, there is a need for a primary neutron source rod mounting structure and a mounting method to solve the above problems. SUMMARY

[0005] The present application aims to provide a primary neutron source rod mounting structure and a mounting method, which simplifies the installation operation process of the primary neutron source rod, shortens the operation time and the personnel exposure time to radioactive irradiation, and reduces the risk of introducing foreign objects.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The primary neutron source rod mounting structure comprises:

[0008] A connecting plate is fixedly provided with a connecting plate rib, and an installation hole is formed in the upper end face of the connecting plate rib;

[0009] A primary neutron source rod body is inserted into the installation hole, and the primary neutron source rod body comprises a californium-252 neutron source and a cladding tube, and the californium-252 neutron source is arranged in the cladding tube;

[0010] A fixed connection assembly is disposed between the primary neutron source rod body and the upper end face of the connecting plate, and is used to fix the primary neutron source rod body to the upper end face of the connecting plate.

[0011] Furthermore, the fixed connection assembly includes a positioning plate and a fastener. The positioning plate is fixedly connected to the upper end of the casing tube. The positioning plate has a first connection hole, and the upper end face of the connecting plate rib has a second connection hole opposite to the first connection hole. The fastener passes through the first connection hole and the second connection hole.

[0012] Furthermore, a plurality of first connecting holes are spaced apart on the positioning plate, and a plurality of second connecting holes are spaced apart on the connecting plate rib. The first connecting holes and the second connecting holes are arranged in a one-to-one correspondence, and the fasteners are provided in each set of the oppositely arranged first connecting holes and second connecting holes.

[0013] Furthermore, the first connecting hole and the second connecting hole are threaded holes, and the fastener is a bolt.

[0014] Furthermore, a positioning groove is provided on the upper end face of the connecting plate rib, the positioning groove is located at the mounting hole, and the positioning plate is located in the positioning groove.

[0015] Furthermore, an elastic washer is fitted onto the fastener, and the elastic washer is sandwiched between the end of the fastener and the connecting rib.

[0016] Furthermore, both the positioning groove and the positioning plate are elongated.

[0017] Furthermore, the edge of the positioning groove is chamfered.

[0018] Furthermore, the positioning plate and the casing tube are an integrated structure.

[0019] The installation method, using the primary neutron source rod installation structure described above, involves installing the primary neutron source rod body, and includes the following steps:

[0020] S1. The californium-252 neutron source is loaded into a cladding tube and encapsulated to form the primary neutron source rod body;

[0021] S2. Hoist the primary neutron source rod body to the mounting hole of the connecting plate, and insert the primary neutron source rod body into the mounting hole;

[0022] S3. Connect the primary neutron source rod body to the upper end face of the connecting plate using a fixed connection assembly.

[0023] The beneficial effects of this invention are:

[0024] The present invention provides a primary neutron source rod installation structure, in which a connecting rib is fixedly provided on a connecting plate, and an installation hole is opened on the upper end face of the connecting rib. The primary neutron source rod body is inserted into the installation hole, and then the primary neutron source rod body is fixed to the upper end face of the connecting plate by a fixing connection assembly provided between the primary neutron source rod body and the upper end face of the connecting plate. During the installation of the primary neutron source rod body, it is not necessary to lift the connecting plate out of the mating fuel assembly; the primary neutron source rod body only needs to be lifted to the installation hole, inserted, and fixed to the connecting plate by the fixing connection assembly. This process only requires a positioning funnel and tools for installing the fixing connection assembly, reducing tool usage, lowering the risk of foreign object introduction, simplifying the installation operation process of the primary neutron source rod, and shortening the installation operation time and the time personnel are exposed to radioactive radiation.

[0025] The installation method provided by this invention uses the primary neutron source rod installation structure as described above to install the primary neutron source rod body, which simplifies the installation operation process of the primary neutron source rod, shortens the installation operation time and the time personnel are exposed to radioactive radiation, and reduces the risk of introducing foreign objects. Attached Figure Description

[0026] Fig. 1 This is a schematic diagram of a primary neutron source rod mounting structure according to the present invention;

[0027] Fig. 2 This is a schematic diagram of the connecting plate in a primary neutron source rod mounting structure of the present invention;

[0028] Fig. 3 This is a schematic diagram of the primary neutron source rod body in a primary neutron source rod mounting structure of the present invention.

[0029] In the picture:

[0030] 1. Connecting plate; 11. Connecting plate rib; 12. Mounting hole; 13. Positioning groove; 14. Second connecting hole; 2. Primary neutron source rod body; 21. Sheath tube; 3. Fixed connection assembly; 31. Positioning plate; 311. First connecting hole; 32. Fastener. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, not all of them.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] During the installation of the primary neutron source rod, in order to simplify the installation process, shorten the installation time and the time personnel are exposed to radioactive radiation, and reduce the risk of introducing foreign objects, such as... Figs. 1-3 As shown, the present invention provides a primary neutron source rod mounting structure. The primary neutron source rod mounting structure includes a connecting plate 1, a primary neutron source rod body 2, and a fixing connection assembly 3.

[0035] The connecting plate 1 is fixedly provided with a connecting plate rib 11, and a mounting hole 12 is provided on the upper end face of the connecting plate rib 11; the primary neutron source rod body 2 is inserted into the mounting hole 12, the primary neutron source rod body 2 includes a californium-252 neutron source and a cladding tube 21, the californium-252 neutron source is disposed in the cladding tube 21; the fixed connection assembly 3 is disposed between the primary neutron source rod body 2 and the upper end face of the connecting plate 1, and is used to fix the primary neutron source rod body 2 to the upper end face of the connecting plate 1.

[0036] During the installation of the primary neutron source rod body 2, it is not necessary to lift the connecting plate 1 out of the mating fuel assembly. The primary neutron source rod body 2 is simply lifted to the mounting hole 12, inserted, and then fixed to the connecting plate 1 using the fixing connection assembly 3. This process only requires a positioning funnel and tools for installing the fixing connection assembly, reducing tool usage, lowering the risk of foreign object introduction, simplifying the installation process of the primary neutron source rod, and shortening the installation time and the time personnel are exposed to radioactive radiation.

[0037] Furthermore, the fixed connection assembly 3 includes a positioning plate 31 and a fastener 32. The positioning plate 31 is fixedly connected to the upper end of the cladding tube 21. The positioning plate 31 has a first connecting hole 311, and the upper end face of the connecting rib 11 has a second connecting hole 14 opposite to the first connecting hole 311. The fastener 32 passes through the first connecting hole 311 and the second connecting hole 14. During installation, the primary neutron source rod body 2 is inserted into the mounting hole 12, the positioning plate 31 abuts against the upper end face of the connecting rib 11, and then the position of the positioning plate 31 is fixed by the fastener 32, thus realizing the installation and fixation of the primary neutron source rod body 2.

[0038] Furthermore, a plurality of first connecting holes 311 are spaced apart on the positioning plate 31, and a plurality of second connecting holes 14 are spaced apart on the connecting rib 11. The first connecting holes 311 and the second connecting holes 14 are arranged in a one-to-one correspondence. A fastener 32 is provided in each set of oppositely arranged first connecting holes 311 and second connecting holes 14. Specifically, in this embodiment, two of each of the first connecting holes 311 and the second connecting holes 14 are provided. In other embodiments, the design can be modified according to actual needs, and no further restrictions are imposed here. Through the above arrangement, the connection strength between the positioning plate 31 and the connecting rib 11 can be improved.

[0039] Furthermore, the first connecting hole 311 and the second connecting hole 14 are threaded holes, and the fastener 32 is a bolt. By adopting a threaded connection, the installation and removal of the fastener 32 are facilitated, thereby facilitating the installation and removal of the primary neutron source rod body 2.

[0040] Furthermore, a positioning groove 13 is provided on the upper end face of the connecting rib 11. The positioning groove 13 is located at the mounting hole 12, and the positioning plate 31 is located in the positioning groove 13. By providing the positioning groove 13, it is convenient to position the positioning plate 31, thereby facilitating the positioning of the primary neutron source rod body 2 and accelerating the installation speed of the primary neutron source rod body 2.

[0041] Furthermore, both the positioning groove 13 and the positioning plate 31 are elongated. By adopting an elongated structure, the positioning plate 31, after being installed in the positioning groove 13, serves to prevent rotation.

[0042] Furthermore, the edge of the positioning groove 13 is chamfered. By providing the chamfer, the opening of the positioning groove 13 is enlarged, making it easier to install the positioning plate 31 into the positioning groove 13 during the installation process.

[0043] Furthermore, a flexible washer is fitted onto the fastener 32, and the flexible washer is sandwiched between the end of the fastener 32 and the connecting rib 11. By setting the flexible washer, a tight clamping effect can be achieved, thus preventing loosening after the fastener 32 is installed in place.

[0044] Furthermore, the positioning plate 31 and the casing tube 21 are an integrated structure. In this embodiment, the positioning plate 31 and the casing tube 21 are fully welded to form an integrated structure. In other embodiments, the positioning plate 31 and the casing tube 21 can be integrally formed, which facilitates manufacturing while ensuring the connection strength between the positioning plate 31 and the casing tube 21.

[0045] This embodiment also provides an installation method, which uses the above-described primary neutron source rod mounting structure to install the primary neutron source rod body 2, including the following steps:

[0046] S1. The californium-252 neutron source is loaded into the cladding tube 21 and encapsulated to form the primary neutron source rod body 2;

[0047] S2. Hoist the primary neutron source rod body 2 to the mounting hole 12 of the connecting plate 1, and insert the primary neutron source rod body 2 into the mounting hole 12;

[0048] S3. Use the fixed connection component 3 to connect the primary neutron source rod body 2 to the upper end face of the connecting plate 1.

[0049] In the above manner, during the installation of the primary neutron source rod body 2, it is not necessary to remove the connecting plate 1. The primary neutron source rod body 2 can be directly inserted into the mounting hole 12 and connected using the fixed connection component 3.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A primary neutron source rod mounting structure, characterized in that, include: A connecting plate (1) is fixedly provided with a connecting plate rib (11), and an installation hole (12) is provided on the upper end surface of the connecting plate rib (11); Primary neutron source rod body (2), the primary neutron source rod body (2) is inserted into the mounting hole (12), the primary neutron source rod body (2) includes a californium-252 neutron source and a cladding tube (21), the californium-252 neutron source is disposed in the cladding tube (21); A fixed connection assembly (3) is disposed between the primary neutron source rod body (2) and the upper end face of the connecting plate (1) for fixing the primary neutron source rod body (2) to the upper end face of the connecting plate (1). The fixed connection assembly (3) includes a positioning plate (31) and a fastener (32). The positioning plate (31) is fixedly connected to the upper end of the casing tube (21). A first connection hole (311) is provided on the positioning plate (31). A second connection hole (14) opposite to the first connection hole (311) is provided on the upper end face of the connecting plate rib (11). The fastener (32) passes through the first connection hole (311) and the second connection hole (14). A plurality of first connecting holes (311) are spaced apart on the positioning plate (31), and a plurality of second connecting holes (14) are spaced apart on the connecting plate rib (11). The first connecting holes (311) and the second connecting holes (14) are arranged in a one-to-one correspondence. In each set of the oppositely arranged first connecting holes (311) and second connecting holes (14), the fastener (32) is provided. The first connecting hole (311) and the second connecting hole (14) are threaded holes, and the fastener (32) is a bolt.

2. The primary neutron source rod mounting structure according to claim 1, characterized in that, The upper end face of the connecting rib (11) is provided with a positioning groove (13), the positioning groove (13) is located at the mounting hole (12), and the positioning plate (31) is located in the positioning groove (13).

3. The primary neutron source rod mounting structure according to claim 2, characterized in that, An elastic washer is fitted on the fastener (32), and the elastic washer is sandwiched between the end of the fastener (32) and the connecting rib (11).

4. The primary neutron source rod mounting structure according to claim 2, characterized in that, Both the positioning groove (13) and the positioning plate (31) are elongated.

5. The primary neutron source rod mounting structure according to claim 2, characterized in that, The positioning groove (13) has a chamfered edge.

6. The primary neutron source rod mounting structure according to claim 1, characterized in that, The positioning plate (31) and the casing tube (21) are an integrated structure.

7. Installation method, characterized in that, The installation of the primary neutron source rod body (2) using the primary neutron source rod mounting structure as described in any one of claims 1-6 includes the following steps: S1. The californium-252 neutron source is loaded into the cladding tube (21) and encapsulated to form the primary neutron source rod body (2); S2. Hoist the primary neutron source rod body (2) to the mounting hole (12) of the connecting plate (1) and insert the primary neutron source rod body (2) into the mounting hole (12); S3. Use the fixed connection assembly (3) to connect the primary neutron source rod body (2) to the upper end face of the connection plate (1).

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