Simulation device special for underwater repair of nuclear fuel assembly

Abstract

The invention discloses a special simulation device for underwater repair of a nuclear fuel assembly. The special simulation device comprises an upper pipe seat, a lower pipe seat, a connecting pipe, an upper supporting plate and a sleeve screw, the upper tube seat and the lower tube seat are respectively arranged at two ends of the connecting tube, the upper tube seat is connected with one end of the connecting tube through the upper supporting plate, and the other end of the connecting tube is connected with the lower tube seat; a plurality of guide pipes are further included, the guide pipes are arranged on the side, away from the connecting pipe, of the upper supporting plate, a plurality of through holes are formed in the upper pipe base, and the sleeve screws are used for penetrating through the through holes to be in threaded connection with inner cavities of the guide pipes. The guide pipe is arranged on the upper supporting plate and is small in length size, so that the overall structure of the device is relatively simple, the guide pipe is not prone to being damaged and abraded, the replacement cost or the maintenance cost is relatively low even if a certain part of the guide pipe is damaged and abraded, and then the underwater repairing work efficiency of the defective fuel assembly of the nuclear power station can be improved, and the construction period is shortened; the safety risk and the labor intensity are reduced, and the fuel operation precision and safety are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power, and in particular to a special simulation device for underwater repair of nuclear fuel components. Background Art

[0002] Before underwater repair of defective fuel assemblies in a nuclear power plant, the repair equipment must be subjected to full-process operation drills and re-identification tests to determine that the various functions of the repair equipment meet the requirements for underwater repair of defective fuel assemblies. This process requires hoisting a set of simulated nuclear fuel assemblies from the spent fuel pool to the new fuel elevator, performing underwater disassembly and assembly of the upper tube seat and replacement of the fuel rods, and then hoisting the simulated nuclear fuel assembly back to the spent fuel pool.

[0003] like Figure 1 As shown, the structure of the simulated nuclear fuel assembly 100 of the related art is the same as or similar to that of the real nuclear fuel assembly, and includes a compression spring 101, an upper tube seat 102, a top positioning grid 103, an intermediate mixing grid 104, a positioning grid 105, a fuel rod 106, a bottom positioning grid 107, a guide tube 108, a chip prevention plate 109, and a lower tube seat 110. The guide tube 108 is similar in size to that of a real nuclear fuel assembly, and its length is close to 4 meters, which makes the structure of the entire simulated nuclear fuel assembly 100 complex, and the damage and wear of the guide tube 108 will affect the overall service life of the simulated nuclear fuel assembly 100. In addition, as Figure 2 As shown, the guide tube 108 and the sleeve screw 111 are interference-fitted by the expansion tube 112. If the simulated nuclear fuel assembly is used for functional verification of the repair equipment, the sleeve screw 111 cannot be disassembled or assembled due to the jamming of the guide tube 108 and the sleeve screw 111 after repeated use (e.g. Figure 2 As shown in the figure, the simulated nuclear fuel assembly is unusable. The simulated nuclear fuel assembly needs to be repaired by water outlet to eliminate the jamming problem of the sleeve screw 111. The water outlet treatment of the simulated nuclear fuel assembly will also generate the risk of radioactive contamination. In addition, each unit is currently equipped with at least one set of simulated nuclear fuel assemblies. When one or more sets of simulated nuclear fuel assemblies are jammed and unusable, it will have a direct impact on the preventive maintenance of the overhaul and refueling equipment, which is easy to delay the maintenance period. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a special simulation device for underwater repair of nuclear fuel components.

[0005] The technical solution adopted by the present invention to solve the technical problem is: construct a special simulation device for underwater repair of nuclear fuel assemblies, including an upper tube seat, a lower tube seat, a connecting tube, an upper support plate and a sleeve screw; the upper tube seat and the lower tube seat are respectively arranged at both ends of the connecting tube, the upper tube seat is connected to one end of the connecting tube through the upper support plate, and the other end of the connecting tube is connected to the lower tube seat;

[0006] The special simulation device for underwater repair of nuclear fuel assemblies also includes multiple guide tubes. The guide tubes are arranged on the side of the upper support plate away from the connecting tube. A plurality of through holes are provided on the upper tube seat. The positions of the through holes correspond to the positions of the guide tubes. The sleeve screws are used to penetrate the through holes to be threadedly connected to the inner cavity of the guide tubes.

[0007] In some embodiments, the length of the guide tube is 60-80 mm.

[0008] In some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies includes a first flange and a second flange;

[0009] The first flange is detachably connected to the upper support plate and the axial upper end of the connecting pipe respectively;

[0010] The second flange is detachably connected to the axial lower end of the connecting pipe and the lower pipe seat respectively.

[0011] In some embodiments, the first flange includes a first main body and a first cylindrical portion, the first main body is detachably connected to the upper support plate; the first cylindrical portion is arranged on a side of the first main body away from the upper support plate, and the upper end of the connecting pipe is threadedly connected to the inner cavity of the first cylindrical portion;

[0012] The second flange includes a second main body and a second cylindrical portion, and the second main body is detachably connected to the lower tube seat via a second fastener; the second cylindrical portion is arranged on a side of the second main body away from the lower tube seat, and the lower end of the connecting pipe is threadedly connected to the inner cavity of the second cylindrical portion.

[0013] In some embodiments, the dedicated underwater repair simulation device for nuclear fuel assemblies further comprises a third flange and a fourth flange, and the third flange and the fourth flange are detachably connected;

[0014] The connecting pipe includes a first sub-connecting pipe and a second sub-connecting pipe, the first sub-connecting pipe is arranged between the first flange and the third flange, and two ends of the first sub-connecting pipe are respectively connected to the first flange and the third flange;

[0015] The second sub-connecting pipe is disposed between the fourth flange and the second flange, and two ends of the second sub-connecting pipe are respectively connected to the fourth flange and the second flange.

[0016] In some embodiments, the third flange includes a third main body portion, a third cylindrical portion and a fourth cylindrical portion, and the third cylindrical portion and the fourth cylindrical portion are respectively disposed on two opposite surfaces of the third main body portion;

[0017] The fourth flange comprises a fourth main body portion, a fifth cylindrical portion and a sixth cylindrical portion, wherein the fifth cylindrical portion and the sixth cylindrical portion are respectively arranged on two opposite surfaces of the fourth main body portion;

[0018] Among them, the third main body portion is connected to the fourth main body portion by a third fastener, the third cylindrical portion is threadedly connected to the lower end of the first sub-connecting pipe, the fourth cylindrical portion is axially connected to the fifth cylindrical portion, and the sixth cylindrical portion is threadedly connected to the upper end of the second sub-connecting pipe.

[0019] In some embodiments, the dedicated underwater repair simulation device for nuclear fuel assemblies further comprises a middle support plate, the middle support plate is installed between the third main body portion and the fourth main body portion, and the middle support plate is sleeved on the outer periphery of the fourth cylindrical portion and the fifth cylindrical portion;

[0020] The third main body portion, the middle support plate and the fourth main body portion are connected by the third fastener.

[0021] In some embodiments, the dedicated underwater repair simulation device for nuclear fuel assemblies further comprises an installation tube, wherein the installation tube is used for installing the simulated fuel rod;

[0022] The mounting tube is mounted in the inner cavity of the connecting tube, and the mounting tube and the connecting tube are coaxially arranged.

[0023] In some embodiments, the first flange is provided with a first limiting groove for the upper end of the mounting tube to pass through, and the second flange is provided with a second limiting groove for the lower end of the mounting tube to pass through.

[0024] In some embodiments, the mounting tube includes a first sub-mounting tube and a second sub-mounting tube, the upper end of the first sub-mounting tube is located in the first limiting groove, and the lower end of the first sub-mounting tube is located in the inner cavity of the fourth cylindrical portion;

[0025] The upper end of the second sub-mounting tube is located in the inner cavity of the fifth cylindrical portion, and the lower end of the second sub-mounting tube is located in the second limiting groove.

[0026] In some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies further comprises:

[0027] A plurality of limit blocks, wherein the limit blocks are sleeved on the mounting tube and abut against the inner wall of the connecting tube. The implementation of the present invention has the following beneficial effects: the special simulation device for underwater repair of nuclear fuel assemblies comprises an upper tube seat, a lower tube seat, a connecting tube, an upper support plate and a sleeve screw; the upper tube seat and the lower tube seat are respectively arranged at the two ends of the connecting tube, the upper tube seat is connected to one end of the connecting tube through the upper support plate, and the other end of the connecting tube is connected to the lower tube seat; it also comprises a plurality of guide tubes, a guide tube is arranged on the side of the upper support plate away from the connecting tube, a plurality of through holes are arranged on the upper tube seat, the positions of the through holes correspond to the positions of the guide tubes, and the sleeve screws are used to penetrate the through holes to be threadedly connected with the inner cavity of the guide tube. The guide tube is arranged on the upper support plate, and its length is small, so that the overall structure of the special simulation device for underwater repair of nuclear fuel assemblies is relatively simple, and the guide tube is not easy to be damaged or worn. Even if a part of the guide tube is damaged or worn, the replacement cost or maintenance cost is relatively low. Moreover, since the guide tube structure is relatively simple, it is not easy to get stuck with the sleeve screw. Even if it gets stuck, the guide tube and / or the sleeve screw can be easily processed, thereby improving the efficiency of underwater repair of defective fuel assemblies in nuclear power plants, shortening the construction period, reducing safety risks and labor intensity, and ensuring the accuracy and safety of fuel operation. In addition, the special simulation device for underwater repair of nuclear fuel assemblies replaces the original simulated nuclear fuel assembly, and each unit of each nuclear power plant can be used interchangeably, eliminating the risk of the simulated nuclear fuel assembly of each unit being damaged and unusable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work. In the drawings:

[0029] Figure 1 It is a schematic diagram of the structure of a simulated nuclear fuel assembly of the related art;

[0030] Figure 2 It is a schematic diagram of the structure of the guide tube and sleeve screw matching in the simulation nuclear fuel assembly of the related technology;

[0031] Figure 3 It is a schematic diagram of the structure of a special simulation device for underwater repair of nuclear fuel assemblies in some embodiments of the present invention;

[0032] Figure 4 yes Figure 3 Detailed view of part A of the special simulation device for underwater repair of nuclear fuel assemblies;

[0033] Figure 5 yes Figure 3 Detailed view of part B of the special simulation device for underwater repair of nuclear fuel assemblies;

[0034] Figure 6 yes Figure 3 Detailed view of part C of the special simulation device for underwater repair of nuclear fuel assemblies;

[0035] Figure 7 yes Figure 3 Detail of Section D of the special simulation device for underwater repair of nuclear fuel assemblies. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0037] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0038] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0039] See also Figure 3 The present invention shows a special simulation device for underwater repair of nuclear fuel assemblies. The special simulation device for underwater repair of nuclear fuel assemblies is mainly suitable for underwater repair projects of defective nuclear fuel assemblies in pressurized water reactor nuclear power plants. It is used to verify whether the various functions of the fuel assembly repair equipment meet the requirements and are available. The special simulation device for underwater repair of nuclear fuel assemblies is used in conjunction with the fuel assembly repair equipment, the fuel plant crane, the new fuel elevator and the transfer pool tilting machine fuel basket, and the sizes and functions match each other.

[0040] Specifically, before underwater repair of defective fuel assemblies in a nuclear power plant, the fuel assembly repair equipment must be subjected to full-process operation drills and re-identification tests to determine that the various functions of the fuel assembly repair equipment meet the requirements for underwater repair of defective fuel assemblies in nuclear power plants. In this process, a set of special simulation devices for underwater repair of nuclear fuel assemblies must be hoisted from the spent fuel pool to the new fuel elevator, and after underwater disassembly and assembly of the upper tube seat 1 of the special simulation device for underwater repair of nuclear fuel assemblies and replacement of simulated fuel rods, the special simulation device for underwater repair of nuclear fuel assemblies must be hoisted back to the spent fuel pool.

[0041] The external dimensions of the special underwater repair simulation device for nuclear fuel assemblies are similar to those of real fuel assemblies, and the weight of the special underwater repair simulation device for nuclear fuel assemblies is similar to or consistent with that of real fuel assemblies. The external dimensions of the special underwater repair simulation device for nuclear fuel assemblies are 214mm×214mm×4060mm. Of course, the external dimensions of the special underwater repair simulation device for nuclear fuel assemblies can be appropriately adjusted according to different real fuel assemblies, for example, the length dimension can be: 200-220mm, the width dimension can be: 200-220mm, the height dimension can be: 4000-4200mm, and no specific limitation is made here.

[0042] like Figures 3 to 7 As shown, in some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies includes an upper tube seat 1, a lower tube seat 2, a connecting tube 3, an upper support plate 4 and a sleeve screw.

[0043] The upper tube seat 1 simulates a real upper tube seat, which is roughly a square structure, and its length and width can be 214mm. The upper tube seat 1 can be provided with a compression spring and other components. The lower tube seat 2 simulates a real lower tube seat, and its lower part can also be provided with a positioning pin hole and the like. The upper support plate 4 simulates a real installation grid.

[0044] Furthermore, the upper tube seat 1, the lower tube seat 2, the connecting tube 3, the upper support plate 4 and the sleeve screw can be made of stainless steel material, such as stainless steel 304 or stainless steel 316L, or titanium alloy, which is not specifically limited here.

[0045] In some embodiments, the upper tube seat 1 and the lower tube seat 2 are respectively arranged at the two ends of the connecting tube 3, the upper tube seat 1 is connected to one end of the connecting tube 3 through the upper support plate 4, and the other end of the connecting tube 3 is connected to the lower tube seat 2. The dedicated simulation device for underwater repair of nuclear fuel assemblies also includes a plurality of guide tubes 5, the guide tubes 5 are arranged on the side of the upper support plate 4 away from the connecting tube 3, the upper tube seat 1 is provided with a plurality of through holes 111, the positions of the through holes 111 correspond to the positions of the guide tubes 5, and the sleeve screws are used to penetrate the through holes 111 to be threadedly connected with the inner cavity of the guide tube 5.

[0046] When it is necessary to conduct a full-process operation drill and re-identification test on the defective fuel assembly repair equipment, the upper tube seat 1 can be disassembled and assembled by rotating the disassembly sleeve screw to connect or separate the upper tube seat 1 from the upper support plate 4.

[0047] like Figure 1 It can be seen that the guide tube of the simulated nuclear fuel assembly in the prior art is similar in size to the guide tube of the real nuclear fuel assembly, and the length is close to 4 meters, which makes the structure of the entire simulated nuclear fuel assembly complicated, and the damage and wear of the guide tube will affect the overall service life of the simulated nuclear fuel assembly. The guide tube 5 of the present application is arranged on the upper support plate 4, and its length is smaller, so that the overall structure of the special simulation device for underwater repair of nuclear fuel assemblies is relatively simple, and the guide tube 5 is not easy to be damaged and worn. Even if a part of the guide tube 5 is damaged or worn, the replacement cost or maintenance cost is relatively low.

[0048] In addition, if Figure 2As shown, the guide tube of the simulated nuclear fuel assembly of the prior art has a large length, and the sleeve screw is connected to the guide tube through its thin-walled expansion tube. Once it gets stuck, it is difficult to disassemble. However, the guide tube 5 of the present application is arranged on the upper support plate 4, and the upper tube seat 1 is connected to the upper support plate 4 through the guide tube 5. The guide tube 5 has a small length, and the sleeve screw directly cooperates with the guide tube 5, so it is not easy to get stuck. Even if it gets stuck, the guide tube 5 and / or the sleeve screw can be easily processed, thereby improving the efficiency of underwater repair of defective fuel assemblies in nuclear power plants, shortening the construction period, reducing safety risks and labor intensity, and ensuring the accuracy and safety of fuel operation. In addition, the special simulation device for underwater repair of nuclear fuel assemblies replaces the original simulated nuclear fuel assembly, and each unit of each nuclear power plant can be used interchangeably, eliminating the risk of the simulated nuclear fuel assembly of each unit being damaged and unusable.

[0049] In some embodiments, the number of the guide tubes 5 is 24, and the number of the sleeve screws is also 24.

[0050] In some embodiments, the length of the guide tube 5 is 60-80 mm, and the length of the guide tube 5 can be 61 mm, 62 mm, 63 mm, 64 mm, 65 mm, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, 71 mm, 72 mm, 73 mm, 74 mm, 75 mm, 76 mm, 77 mm, 78 mm, 79 mm, 80 mm. Preferably, the length of the guide tube 5 can be 67 mm. Compared with the 4-meter length of the guide tube in the prior art, the length of the guide tube 5 of the present application is greatly reduced, which can reduce the matching size of the sleeve screw and the guide tube 5, and it is more convenient to replace and disassemble the guide tube 5.

[0051] In some embodiments, the inner cavity of the guide tube 5 is processed with an internal thread, and the axial length of the internal thread can be 15-20 mm, for example, the axial length of the internal thread can be 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm. Preferably, the axial length of the internal thread can be 17 mm, and the specification of the internal thread can be a 17 mm M14×1 internal thread. It can be understood that the axial length of the internal thread of the guide tube 5 is relatively small, and while ensuring a stable fit with the sleeve screw, the fitting length between the two is reduced, so that the two are not prone to jamming problems.

[0052] Preferably, the length of the guide tube 5 can be 67 mm, and the inner cavity of the guide tube 5 is processed with an M14×1 internal thread with a depth of 17 mm. The screw section of the sleeve screw of the simulated nuclear fuel assembly in the related art is M14×13, and the pitch is 1 mm. The sleeve screw of this specification is easy to get stuck and cause the two to be unable to be disassembled. The length of the guide tube 5 of the present application can be 67 mm, and the inner cavity of the guide tube 5 can be processed with an M14×1 internal thread with a depth of 17 mm. After the sleeve screw is connected to the inner cavity thread of the guide tube 5, it is easier to disassemble and assemble, and it is not easy to get stuck. The upper tube seat 1 and the upper support plate 4 can be quickly assembled and disassembled, and then the rapid assembly and disassembly of the entire nuclear fuel assembly underwater repair special simulation device can be effectively reduced, which can effectively shorten the time for re-identification test of the function of defective fuel assembly equipment and improve efficiency and safety.

[0053] In some embodiments, the upper end of the connecting tube 3 is detachably connected to the upper support plate 4, and the lower end of the connecting tube 3 is detachably connected to the lower tube seat 2. The components are detachably assembled to facilitate modular production and rapid transportation.

[0054] In some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies includes a first flange 31 and a second flange 32. The first flange 31 is detachably connected to the upper support plate 4 and the axial upper end of the connecting pipe 3, respectively; the second flange 32 is detachably connected to the axial lower end of the connecting pipe 3 and the lower pipe seat 2, respectively. Preferably, the first flange 31, the upper support plate 4, the connecting pipe 3, the second flange 32 and the lower pipe seat 2 can be coaxially arranged.

[0055] The structures of the first flange 31 and the second flange 32 are introduced in sequence below. The structure of the first flange 31 is introduced first.

[0056] like Figure 4As shown, in some embodiments, the first flange 31 includes a first main body 311 and a first cylindrical portion 312, and the first main body 311 is detachably connected to the upper support plate 4; the first cylindrical portion 312 is arranged on the side of the first main body 311 away from the upper support plate 4, and the upper end of the connecting pipe 3 is threadedly connected to the inner cavity of the first cylindrical portion 312. Specifically, the first main body 311 is generally a plate-shaped structure, such as a circular plate-shaped structure or a flat cylindrical structure, and the first main body 311 is detachably connected to the upper support plate 4 through a first fastener 33, for example, the first main body 311 is provided with a plurality of first connecting holes, and the upper support plate 4 is provided with a plurality of second connecting holes, and the first fastener 33 is sequentially penetrated through the first connecting holes and the second connecting holes to connect and fix the first main body 311 and the upper support plate 4, thereby realizing the connection between the first flange 31 and the upper support plate 4. Preferably, the first fastener 33 includes but is not limited to bolts or screws. The upper end of the connecting tube 3 is threadedly connected to the inner cavity of the first cylindrical portion 312. For example, if the upper end of the connecting tube 3 is provided with an external thread surface, the inner cavity of the first cylindrical portion 312 is provided with an internal thread, and the two are threadedly connected and fixed. Preferably, the cross-sectional dimension of the first cylindrical portion 312 can be smaller than the cross-sectional dimension of the first main body portion 311. For example, when the first main body portion 311 is a circular plate-shaped structure or a flat cylindrical structure, the first cylindrical portion 312 is roughly a cylindrical structure, and the outer diameter of the first main body portion 311 can be larger than the outer diameter of the first cylindrical portion 312. The portion of the first main body portion 311 located outside the first cylindrical portion 312 is detachably connected to the upper support plate 4 through the first fastener 33.

[0057] Further, the upper support plate 4 is provided with a first positioning hole 41, such as the first positioning hole 41 is provided at the center of the upper support plate 4. A first positioning portion 313 matching the first positioning hole 41 is provided on one side of the first main body portion 311, and the first positioning portion 313, the first main body portion 311 and the first cylindrical portion 312 may be coaxially arranged, and the inner cavities of the three are interconnected, and the first positioning portion 313 may be a cylindrical structure, and the outer diameter of the first positioning portion 313 is less than or equal to the outer diameter of the first cylindrical portion 312.

[0058] Among them, when the first flange 31 and the upper support plate 4 are assembled together, the first positioning portion 313 can be first inserted into the first positioning hole 41 to achieve positioning and pre-fixation, which can improve the centering of the first flange 31, and when the first flange 31 and the upper support plate 4 are assembled together, the first positioning portion 313 and the first positioning hole 41 limit each other, which can improve the connection stability between the first flange 31 and the upper support plate 4.

[0059] The structure of the second flange 32 is described below. Figure 5As shown, in some embodiments, the second flange 32 includes a second main body portion 321 and a second cylindrical portion 322, and the second main body portion 321 is detachably connected to the lower tube seat 2 via a second fastener 34; the second cylindrical portion 322 is arranged on the side of the second main body portion 321 away from the lower tube seat 2, and the lower end of the connecting tube 3 is threadedly connected to the inner cavity of the second cylindrical portion 322.

[0060] Specifically, the second main body 321 is generally a plate-shaped structure, for example, the second main body 321 can be a circular plate-shaped structure or a flat cylindrical structure, and the second main body 321 and the lower tube seat 2 are detachably connected through the second fastener 34, for example, the second main body 321 is provided with a plurality of third connection holes, and the lower tube seat 2 is provided with a plurality of fourth connection holes, and the second fastener 34 is sequentially penetrated through the third connection holes and the fourth connection holes to connect and fix the second main body 321 and the lower tube seat 2, thereby realizing the connection between the second flange 32 and the lower tube seat 2. Preferably, the second fastener 34 includes but is not limited to bolts or screws.

[0061] Further, the axial lower end of the connecting tube 3 is threadedly connected with the inner cavity of the second cylindrical portion 322. For example, the axial lower end of the connecting tube 3 is provided with an external threaded surface, and the inner cavity of the second cylindrical portion 322 is provided with an internal thread, and the two are threadedly connected and fixed. Preferably, the cross-sectional dimension of the second cylindrical portion 322 can be smaller than the cross-sectional dimension of the second main body portion 321. For example, when the second main body portion 321 is a circular plate-shaped structure or a flat cylindrical structure, the second cylindrical portion 322 is roughly a cylindrical structure, and the outer diameter of the second main body portion 321 can be larger than the outer diameter of the second cylindrical portion 322. The part of the second main body portion 321 located outside the second cylindrical portion 322 is detachably connected to the lower tube seat 2 through the second fastener 34.

[0062] Further, the lower tube seat 2 is provided with a second positioning hole 21, such as the second positioning hole 21 is provided at the center of the lower tube seat 2. A second positioning portion 323 matching the second positioning hole 21 is provided on one side of the second main body 321, and the second positioning portion 323, the second main body 321 and the second cylindrical portion 322 can be coaxially arranged, and the inner cavities of the three are interconnected, and the second positioning portion 323 can be a cylindrical structure, and the outer diameter of the second positioning portion 323 is less than or equal to the outer diameter of the second cylindrical portion 322.

[0063] Among them, when the second flange 32 and the lower tube seat 2 are assembled together, the second positioning portion 323 can be first inserted into the second positioning hole 21 to achieve positioning and pre-fixation, which can improve the centering of the second flange 32, and when the second flange 32 and the lower tube seat 2 are assembled together, the second positioning portion 323 and the second positioning hole 21 limit each other, which can improve the connection stability between the second flange 32 and the lower tube seat 2.

[0064] It can be understood that the connection pipe 3, the first flange 31 and the second flange 32 are connected by threads, which have good centering and positioning reference, thereby ensuring the overall straightness and centering of the simulation component.

[0065] Of course, in some embodiments, the first flange 31 may be an integral structure with the upper end of the connecting pipe 3, and the second flange 32 may be an integral structure with the lower end of the connecting pipe 3, which can reduce the assembly process.

[0066] In some embodiments, the connecting pipe 3 may be a segmented structure or a split structure, so as to facilitate assembly and transportation, and occupy a smaller storage space during transportation. The segmented structure and its assembly method are described in detail below.

[0067] like Figure 3 and Figure 6 As shown, in some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies further includes a third flange 35 and a fourth flange 36, and the third flange 35 and the fourth flange 36 are detachably connected;

[0068] The connecting pipe 3 includes a first sub-connecting pipe 3a and a second sub-connecting pipe 3b. The first sub-connecting pipe 3a is disposed between the first flange 31 and the third flange 35, and both ends of the first sub-connecting pipe 3a are connected to the first flange 31 and the third flange 35 respectively.

[0069] The second sub-connecting pipe 3 b is disposed between the fourth flange 36 and the second flange 32 , and both ends of the second sub-connecting pipe 3 b are connected to the fourth flange 36 and the second flange 32 , respectively.

[0070] The first sub-connecting pipe 3a and the second sub-connecting pipe 3b have the same structure and size, so as to facilitate processing and production and improve the tolerance of assembly.

[0071] The upper end of the first sub-connecting pipe 3a is connected to the aforementioned first flange 31, and the first sub-connecting pipe 3a can be threadedly connected and fixed to the first flange 31, or the first sub-connecting pipe 3a can also be an integral structure with the first flange 31. The lower end of the first sub-connecting pipe 3a is connected to the third flange 35, and the lower end of the first sub-connecting pipe 3a can be threadedly connected and fixed to the third flange 35, or the first sub-connecting pipe 3a can also be an integral structure with the third flange 35.

[0072] Similarly, the upper end of the second sub-connecting pipe 3b is connected to the fourth flange 36, and the lower end of the second sub-connecting pipe 3b is connected to the second flange 32. The upper end of the second sub-connecting pipe 3b can be threadedly connected and fixed to the fourth flange 36 or the two are an integral structure, and the lower end of the second sub-connecting pipe 3b can be threadedly connected and fixed to the second flange 32 or the two are an integral structure. The third flange 35 and the fourth flange 36 are detachably connected to connect the first sub-connecting pipe 3a and the second sub-connecting pipe 3b.

[0073] It can be understood that the connecting pipe 3 is assembled with a segmented structure. When any sub-connecting pipe is damaged, the sub-connecting pipe can be repaired or replaced as needed, which can improve the efficiency of fault repair.

[0074] In some embodiments, the third flange 35 includes a third main body portion 351, a third cylindrical portion 352 and a fourth cylindrical portion 353, and the third cylindrical portion 352 and the fourth cylindrical portion 353 are respectively arranged on two opposite surfaces of the third main body portion 351; the third cylindrical portion 352, the third main body portion 351 and the fourth cylindrical portion 353 are coaxially arranged, and the inner cavities of the three are connected, the third cylindrical portion 352, the third main body portion 351 and the fourth cylindrical portion 353 can all be roughly cylindrical, and the outer diameter of the third cylindrical portion 352 is smaller than the outer diameter of the third main body portion 351, and the outer diameter of the third cylindrical portion 352 is larger than the outer diameter of the fourth cylindrical portion 353.

[0075] Similarly, the fourth flange 36 includes a fourth main body 361, a fifth cylindrical portion 362 and a sixth cylindrical portion 363, and the fifth cylindrical portion 362 and the sixth cylindrical portion 363 are respectively arranged on two opposite surfaces of the fourth main body 361; the fifth cylindrical portion 362, the fourth main body 361 and the sixth cylindrical portion 363 are coaxially arranged, and the inner cavities of the three are connected, the fifth cylindrical portion 362, the fourth main body 361 and the sixth cylindrical portion 363 can all be roughly cylindrical, and the outer diameter of the sixth cylindrical portion 363 is smaller than the outer diameter of the fourth main body 361, and the outer diameter of the sixth cylindrical portion 363 is larger than the outer diameter of the fifth cylindrical portion 362.

[0076] Among them, the third main body part 351 and the fourth main body part 361 are connected by the third fastener 37, the third cylindrical part 352 is threadedly connected to the lower end of the first sub-connecting tube 3a, the fourth cylindrical part 353 and the fifth cylindrical part 362 are axially connected, and the sixth cylindrical part 363 is threadedly connected to the upper end of the second sub-connecting tube 3b.

[0077] Specifically, the third cylindrical portion 352 is threadedly connected to the axial lower end of the first sub-connecting pipe 3a, such as the inner cavity of the third cylindrical portion 352 is provided with an internal thread, the axial lower end of the first sub-connecting pipe 3a is provided with an external thread, and the two are threadedly connected, the fourth cylindrical portion 353 is axially connected to the fifth cylindrical portion 362, and the sixth cylindrical portion 363 is threadedly connected to the axial upper end of the second sub-connecting pipe 3b, such as the inner cavity of the sixth cylindrical portion 363 is provided with an internal thread, the axial upper end of the second sub-connecting pipe 3b is provided with an external thread, and the two are threadedly connected. The third main body 351 and the fourth main body 361 are connected by a third fastener 37 to connect the third flange 35 and the fourth flange 36, and then connect the first sub-connecting pipe 3a and the second sub-connecting pipe 3b, and the first sub-connecting pipe 3a and the second sub-connecting pipe 3b are coaxially arranged.

[0078] In some embodiments, the dedicated underwater repair simulation device for nuclear fuel assemblies further includes a middle support plate 6, which is installed between the third main body 351 and the fourth main body 361, and the middle support plate 6 is sleeved on the outer periphery of the fourth cylindrical part 353 and the fifth cylindrical part 362. The third main body 351, the middle support plate 6 and the fourth main body 361 are connected by a third fastener 37.

[0079] Specifically, the middle support plate 6 simulates the middle grid of a real fuel assembly. The middle support plate 6 can be a square plate structure, and the middle support plate 6 is installed between the third main body 351 and the fourth main body 361, and the middle support plate 6 is sleeved on the outer periphery of the fourth cylindrical part 353 and the fifth cylindrical part 362.

[0080] The third main body 351, the middle support plate 6 and the fourth main body 361 are connected by the third fastener 37, which clamps and fixes the middle support plate 6 while realizing the connection between the third flange 35 and the fourth flange 36. Since the size of the middle support plate 6 is larger than that of the third flange 35 and the fourth flange 36, the detachable installation method can facilitate the transportation and storage of the middle support plate 6, and also facilitate the disassembly and maintenance of the middle support plate 6.

[0081] Of course, in other embodiments, the middle support plate 6 may also be an integral structure with the first sub-connecting pipe 3a or the second sub-connecting pipe 3b, or, when the connecting pipe 3 is an integral structure instead of a split structure, the middle support plate 6 may also be an integral structure with the connecting pipe 3.

[0082] In some embodiments, the dedicated underwater repair simulation device for nuclear fuel assemblies further includes a simulated fuel rod to simulate the clamping and insertion operations of a real fuel rod. The shape and size of the simulated fuel rod may be the same as that of a real fuel rod. Furthermore, the simulated fuel rod may be made of stainless steel or titanium alloy, and may be a solid rod.

[0083] In some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies also includes a mounting tube 7, which is used for the installation of simulated fuel rods. The mounting tube 7 is installed in the inner cavity of the connecting tube 3, and the mounting tube 7 is coaxially arranged with the connecting tube 3.

[0084] Furthermore, the mounting tube 7 can also be defined as a "fuel rod mounting tube" or a "fuel rod casing" or a "fuel rod sleeve". The mounting tube 7 is installed in the inner cavity of the connecting tube 3, and the mounting tube 7 is coaxially arranged with the connecting tube 3. The upper end of the mounting tube 7 can be connected to the inner cavity of the first flange 31 or the first positioning hole 41 of the upper support plate 4. The simulated fuel rod can be installed in the mounting tube 7 or taken out from the mounting tube 7 through the first positioning hole 41 of the upper support plate 4 or the upper end opening of the first flange 31.

[0085] In some embodiments, the mounting tube 7 may be an integral structure, the first flange is provided with a first limiting groove 31a for the upper end of the mounting tube to pass through, and the second flange is provided with a second limiting groove 32a for the lower end of the mounting tube to pass through. Specifically, the first main body 311 is provided with a first limiting groove 31a, the second main body 321 is provided with a second limiting groove 32a, the upper end of the mounting tube 7 is located in the first limiting groove 31a, the lower end of the mounting tube 7 is located in the second limiting groove 32a, the middle part of the mounting tube 7 passes through the inner cavity of the fourth cylindrical part 353 and the fifth cylindrical part 362, and the outer diameter of the mounting tube 7 is the same as the inner diameter of the first limiting groove 31a, the inner diameter of the second limiting groove 32a, the inner diameter of the inner cavity of the fourth cylindrical part 353, and the inner diameter of the inner cavity of the fifth cylindrical part 362.

[0086] like Figures 3 to 6 As shown, in some embodiments, the mounting tube 7 can be a segmented structure or a split structure, and the mounting tube 7 includes a first sub-mounting tube 7a and a second sub-mounting tube 7b. The mounting tube 7 can include a first sub-mounting tube 7a and a second sub-mounting tube 7b, and the first sub-mounting tube 7a and the second sub-mounting tube 7b have the same structural dimensions, which can improve the assembly tolerance and effectively reduce the production cost.

[0087] The upper end of the first sub-mounting tube 7a is located in the first limiting groove 31a, and the lower end of the first sub-mounting tube 7a is located in the inner cavity of the fourth cylindrical portion 353. The upper end of the second sub-mounting tube 7b is located in the inner cavity of the fifth cylindrical portion 362, and can abut against the lower end of the first sub-mounting tube 7a, and the lower end of the second sub-mounting tube 7b is located in the second limiting groove 32a. Preferably, the outer diameter of the mounting tube 7 is the same as the inner diameter of the first limiting groove 31a, the inner diameter of the second limiting groove 32a, the inner diameter of the inner cavity of the fourth cylindrical portion 353, and the inner diameter of the inner cavity of the fifth cylindrical portion 362, so that the mounting tube 7 is installed more stably.

[0088] like Figure 5 As shown, further, the dedicated underwater repair simulation device for nuclear fuel assemblies may also include an end plug 38 for sealing the inner cavity of the second flange 32. For example, the end plug 38 may be an end portion that seals the sixth cylindrical portion 363. The end plug 38 may be located in the second positioning hole 21 and connected to the end portion of the second flange 32 through a fourth fastener 39. For example, the sixth cylindrical portion 363 may be connected and fixed, and the lower end of the mounting tube 7 or the lower end of the second sub-mounting tube 7b abuts against the end surface of the end plug 38. The fourth fastener 39 includes but is not limited to bolts or screws. Of course, in some embodiments, the end portion of the second flange 32 may be a closed structure.

[0089] In some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies further includes: a plurality of limit blocks 8 , which are sleeved on the mounting tube 7 and abut against the inner wall of the connecting tube 3 .

[0090] Among them, a number of limit blocks 8 are located between the outer wall surface of the mounting tube 7 and the inner wall surface of the connecting tube 3, and a number of limit blocks 8 are extended and arranged at axial intervals along the connecting tube 3. The limit blocks 8 can be roughly annular, and the circumferential outer side surface of the limit block 8 is provided with a first limit hole, and the tube wall of the connecting tube 3 can be provided with a second limit hole matching the first limit hole. The fifth fastener 9 passes through the second limit hole and the first limit hole to connect and fix the limit block 8, and the fifth fastener 9 includes but is not limited to bolts or screws.

[0091] Alternatively, in some embodiments, the limiting block 8 may also be fixed to the outer circumference of the mounting tube 7, and the two are an integrated structure.

[0092] Furthermore, at least one end of the limit block 8 in the axial direction is provided with a tapered groove 81, and the inner diameter of the tapered groove 81 gradually decreases from the axial end surface of the limit block 8 to the middle of the limit block 8, so as to form a guide surface 811 on the inner wall surface of the tapered groove 81, so as to facilitate the installation tube 7 to smoothly pass through the inner cavity of the limit block 8. Pre-selectively, both ends of the limit block 8 in the axial direction are provided with tapered grooves 81, so that both ends of the limit block 8 have guide surfaces, which can improve the fault tolerance of the limit block 8. Furthermore, the two tapered grooves 81 are arranged at intervals in the height direction, so that the inner cavity wall surface of the limit block 8 maintains stable contact with the outer wall surface of the installation tube 7, so as to effectively support and effectively limit the installation tube 7, and the limit block 8 maintains sufficient structural rigidity.

[0093] The limit block 8 has the following beneficial effects: it can keep the installation tube 7 and the connecting tube 3 aligned, with their axes coinciding, thus avoiding the installation tube 7 from being skewed, and making the loading and unloading of the simulated fuel rods smoother. In addition, the limit block 8 can also act as a counterweight block.

[0094] For example Figure 3As shown, in some embodiments, the height distance X1 between the upper surface of the upper support plate 4 and the bottom surface of the lower tube seat 2 can be 3970 mm, the height distance X2 between the upper surface of the upper support plate 4 and the upper surface of the middle support plate 6 can be 1910 mm, and the height distance X3 between the upper surface of the middle support plate 6 and the lower surface of the main body of the lower tube seat 2 can be 2000 mm. Of course, the height dimensions can also be selected and set according to actual needs, and are not specifically limited here.

[0095] In this embodiment, the dedicated simulation device for underwater repair of nuclear fuel assemblies can realize the disassembly and assembly operation process of the upper tube seat 1, including the disassembly and assembly of the upper tube seat 1, and the removal and installation of the sleeve screws.

[0096] In addition, the special simulation device for underwater repair of nuclear fuel assemblies is equipped with simulated fuel rods, which can realize the operation process of replacing simulated fuel rods, including simulated fuel rod grabbing, withdrawal and insertion of replacement stainless steel rods.

[0097] Specifically, the special simulation device for underwater repair of nuclear fuel assemblies is an important part of underwater repair of defective fuel assemblies. It is mainly used for re-identification test of defective fuel assembly repair equipment. The operation method includes: removing the sleeve screw of the upper tube seat 1, removing the upper tube seat 1, pulling out the simulated fuel rod, inserting the replacement fuel rod, reinstalling the upper tube seat 1, reinstalling the sleeve screw and locking it.

[0098] In this embodiment, the dedicated simulation device for underwater repair of nuclear fuel assemblies has the following technical effects:

[0099] (1) It improves the efficiency of underwater repair of defective fuel assemblies in nuclear power plants, shortens construction period, reduces safety risks and labor intensity, and ensures the accuracy and safety of fuel operations.

[0100] (2) The special underwater repair simulation device for nuclear fuel assemblies has replaced the original simulated nuclear fuel assemblies. Each unit in each nuclear power plant can use the same device, eliminating the risk of damage and unavailability of the simulated nuclear fuel assemblies of each unit.

[0101] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope covered by the claims of the present invention.

Claims

1. A special simulation device for underwater repair of nuclear fuel assemblies, characterized in that: It comprises an upper tube seat (1), a lower tube seat (2), a connecting tube (3), an upper support plate (4) and a sleeve screw; the upper tube seat (1) and the lower tube seat (2) are respectively arranged at two ends of the connecting tube (3); the upper tube seat (1) is connected to one end of the connecting tube (3) through the upper support plate (4), and the other end of the connecting tube (3) is connected to the lower tube seat (2); The nuclear fuel assembly underwater repair special simulation device also includes a plurality of guide tubes (5), the guide tubes (5) are arranged on the side of the upper support plate (4) away from the connecting tube (3), a plurality of through holes (111) are arranged on the upper tube seat (1), the positions of the through holes (111) correspond to the positions of the guide tubes (5), and the sleeve screws are used to penetrate the through holes (111) to be threadedly connected with the inner cavity of the guide tubes (5).

2. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 1 is characterized in that: The length of the guide tube (5) is 60-80 mm.

3. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 1 or 2, characterized in that: The dedicated simulation device for underwater repair of nuclear fuel assemblies comprises a first flange (31) and a second flange (32); The first flange (31) is detachably connected to the upper support plate (4) and the axial upper end of the connecting pipe (3) respectively; The second flange (32) is detachably connected to the axial lower end of the connecting pipe (3) and the lower pipe seat (2) respectively.

4. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 3 is characterized in that: The first flange (31) comprises a first main body portion (311) and a first cylindrical portion (312), wherein the first main body portion (311) is detachably connected to the upper support plate (4); the first cylindrical portion (312) is arranged on a side of the first main body portion (311) away from the upper support plate (4), and the upper end of the connecting pipe (3) is threadedly connected to the inner cavity of the first cylindrical portion (312); The second flange (32) comprises a second main body portion (321) and a second cylindrical portion (322); the second main body portion (321) is detachably connected to the lower tube seat (2) via a second fastener (34); the second cylindrical portion is arranged on a side of the second main body portion (321) away from the lower tube seat (2), and the lower end of the connecting tube (3) is threadedly connected to the inner cavity of the second cylindrical portion (322).

5. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 3 is characterized in that: The dedicated underwater repair simulation device for nuclear fuel assemblies further comprises a third flange (35) and a fourth flange (36), wherein the third flange (35) and the fourth flange (36) are detachably connected; The connecting pipe (3) comprises a first sub-connecting pipe (3a) and a second sub-connecting pipe (3b); the first sub-connecting pipe (3a) is arranged between the first flange (31) and the third flange (35), and two ends of the first sub-connecting pipe (3a) are respectively connected to the first flange (31) and the third flange (35); The second sub-connecting pipe (3b) is arranged between the fourth flange (36) and the second flange (32), and two ends of the second sub-connecting pipe (3b) are respectively connected to the fourth flange (36) and the second flange (32).

6. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 5 is characterized in that: The third flange (35) comprises a third main body portion (351), a third cylindrical portion (352) and a fourth cylindrical portion (353), wherein the third cylindrical portion (352) and the fourth cylindrical portion (353) are respectively arranged on two opposite surfaces of the third main body portion (351); The fourth flange (36) comprises a fourth main body portion (361), a fifth cylindrical portion (362) and a sixth cylindrical portion (363), wherein the fifth cylindrical portion (362) and the sixth cylindrical portion (363) are respectively arranged on two opposite surfaces of the fourth main body portion (361); Among them, the third main body portion (351) is connected to the fourth main body portion (361) through a third fastener (37), the third cylindrical portion (352) is threadedly connected to the lower end of the first sub-connecting tube (3a), the fourth cylindrical portion (353) is axially connected to the fifth cylindrical portion (362), and the sixth cylindrical portion (363) is threadedly connected to the upper end of the second sub-connecting tube (3b).

7. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 6, characterized in that: The nuclear fuel assembly underwater repair special simulation device also includes a middle support plate (6), the middle support plate (6) is installed between the third main body (351) and the fourth main body (361), and the middle support plate (6) is sleeved on the outer periphery of the fourth cylindrical part (353) and the fifth cylindrical part (362); The third main body portion (351), the middle support plate (6) and the fourth main body portion (361) are connected via the third fastener (37).

8. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 6, characterized in that: The dedicated underwater repair simulation device for nuclear fuel assemblies also includes a mounting tube (7), wherein the mounting tube (7) is used for mounting the simulated fuel rod; The mounting tube (7) is installed in the inner cavity of the connecting tube (3), and the mounting tube (7) and the connecting tube (3) are coaxially arranged.

9. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 8, characterized in that: The first flange is provided with a first limiting groove (31a) for the upper end of the mounting pipe to pass through, and the second flange is provided with a second limiting groove (32a) for the lower end of the mounting pipe to pass through.

10. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 9, characterized in that: The mounting tube (7) comprises a first sub-mounting tube (7a) and a second sub-mounting tube (7b), the upper end of the first sub-mounting tube (7a) being located in the first limiting groove (31a), and the lower end of the first sub-mounting tube (7a) being located in the inner cavity of the fourth cylindrical portion (353); The upper end of the second sub-mounting tube (7b) is located in the inner cavity of the fifth cylindrical portion (362), and the lower end of the second sub-mounting tube (7b) is located in the second limiting groove (32a).

11. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 8, characterized in that: The dedicated simulation device for underwater repair of nuclear fuel assemblies also includes: A plurality of limit blocks (8) are sleeved on the mounting tube (7) and abut against the inner wall of the connecting tube (3).

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