Special simulation device for underwater repair of nuclear fuel assemblies

Abstract

The application discloses a special simulation device for underwater repair of nuclear fuel assemblies, which comprises an upper pipe base, a lower pipe base, a connecting pipe, an upper support plate and a sleeve screw; the upper pipe base and the lower pipe base are arranged at two ends of the connecting pipe respectively, the upper pipe base is connected with one end of the connecting pipe through the upper support plate, and the other end of the connecting pipe is connected with the lower pipe base; a plurality of guide pipes are further arranged, the side of the upper support plate, which is away from the connecting pipe, is provided with the guide pipes, a plurality of through holes are arranged on the upper pipe base, and the sleeve screw is arranged to pass through the through holes and be screwed with the inner cavities of the guide pipes. The guide pipes are arranged on the upper support plate and have small length dimensions, so that the overall structure of the device is relatively simple, the guide pipes are not easy to be damaged and abraded, even if some guide pipes are damaged and abraded, the replacement cost or the maintenance cost is relatively low, and then the working efficiency of underwater repair of defective fuel assemblies of nuclear power plants can be improved, the construction period can be shortened, the safety risk and the labor intensity can be reduced, and the fuel operation precision and safety can be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear power, in particular to a simulation device special for underwater repair of nuclear fuel assemblies. BACKGROUND

[0002] Before underwater repair of defective fuel assemblies in a nuclear power plant, full-process operation rehearsal and re-qualification tests are performed on the repair equipment to determine that the functions of the repair equipment meet the requirements for underwater repair of defective fuel assemblies, which requires hoisting a group of simulated nuclear fuel assemblies from a spent fuel pool to a new fuel hoist, performing underwater disassembly and assembly of the upper nozzle, and replacing the fuel rods, and then hoisting the simulated nuclear fuel assemblies back to the spent fuel pool.

[0003] As shown in Figure 1 , the structure of the simulated nuclear fuel assembly 100 in the related art is the same as or similar to that of a real nuclear fuel assembly, and both include a compression spring 101, an upper nozzle 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 guard 109, and a lower nozzle 110. The guide tube 108 is similar in size to the guide tube of a real nuclear fuel assembly, and has a length close to 4 meters, making the entire simulated nuclear fuel assembly 100 complex in structure, and the breakage and wear of the guide tube 108 affecting the overall service life of the simulated nuclear fuel assembly 100. In addition, as shown in Figure 2 , the guide tube 108 and the sleeve screw 111 are interference-fitted through an expansion tube 112, and if used for verification of the functions of the repair equipment, the simulated nuclear fuel assembly cannot be used after repeated use due to jamming of the guide tube 108 and the sleeve screw 111, which makes the sleeve screw 111 unable to be disassembled (as shown in Figure 2 ), and in turn causes the simulated nuclear fuel assembly to be unusable. The simulated nuclear fuel assembly needs to be treated out of water to eliminate the jamming problem of the sleeve screw 111, which also poses a risk of radioactive contamination during the out-of-water treatment. In addition, at least one set of simulated nuclear fuel assembly is provided for each unit, and when one or more sets of simulated nuclear fuel assemblies are jammed and unusable, it directly affects the preventive maintenance of the refueling equipment, and easily delays the maintenance period. SUMMARY

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

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows: constructing 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. Several 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 being detachably connected to the upper support plate; the first cylindrical portion is disposed on a side of the first main body facing away from the upper support plate, and the upper end of the connecting tube 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 through a second fastener; the second cylindrical portion is arranged on the 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, wherein 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 both ends of the first sub-connecting pipe are connected to the first flange and the third flange respectively;

[0015] The second sub-connection pipe is arranged between the fourth flange and the second flange, and two ends of the second sub-connection pipe are connected with the fourth flange and the second flange respectively.

[0016] In some embodiments, the third flange comprises a third main body part, a third cylindrical part and a fourth cylindrical part, the third cylindrical part and the fourth cylindrical part are arranged on two surfaces of the third main body part respectively;

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

[0018] The third main body part and the fourth main body part are connected by a third fastener, the third cylindrical part is threadedly connected with the lower end of the first sub-connection pipe, the fourth cylindrical part is axially connected with the fifth cylindrical part, and the sixth cylindrical part is threadedly connected with the upper end of the second sub-connection pipe.

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

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

[0021] In some embodiments, the simulation device for underwater repair of nuclear fuel assemblies further comprises an installation pipe, the installation pipe is used for installing a simulation fuel rod;

[0022] The installation pipe is installed in the inner cavity of the connection pipe, and the installation pipe and the connection pipe are coaxially arranged.

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

[0024] In some embodiments, the installation pipe comprises a first sub-installation pipe and a second sub-installation pipe, the upper end of the first sub-installation pipe is located in the first limiting slot, and the lower end of the first sub-installation pipe is located in the inner cavity of the fourth cylindrical part;

[0025] The upper end of the second sub-installation pipe is located in the inner cavity of the fifth cylindrical part, and the lower end of the second sub-installation pipe is located in the second limiting slot.

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

[0027] The plurality of limiting blocks are sleeved on the mounting pipe and abut against the inner wall of the connecting pipe. The nuclear fuel assembly underwater repair special simulation device has the following beneficial effects: the nuclear fuel assembly underwater repair special simulation device comprises an upper pipe seat, a lower pipe seat, a connecting pipe, an upper support plate and a sleeve screw; the upper pipe seat and the lower pipe seat are arranged at two ends of the connecting pipe respectively, the upper pipe seat is connected with one end of the connecting pipe through the upper support plate, and the other end of the connecting pipe is connected with the lower pipe seat; a plurality of guide pipes are further arranged, the side of the upper support plate away from the connecting pipe is provided with the guide pipes, a plurality of through holes are arranged on the upper pipe seat, the positions of the through holes correspond to the positions of the guide pipes, and the sleeve screw is used for penetrating the through holes to be threadedly connected with the inner cavities of the guide pipes. The guide pipes are arranged on the upper support plate and have a relatively small length size, so that the overall structure of the nuclear fuel assembly underwater repair special simulation device is relatively simple, the guide pipes are not easy to be damaged and worn, even if some of the guide pipes are damaged and worn, the replacement cost or the maintenance cost is relatively low, and since the structure of the guide pipes is relatively simple, the guide pipes are not easy to be jammed with the sleeve screw, even if the jamming occurs, the guide pipes and / or the sleeve screw can be easily processed, thereby the nuclear power plant defective fuel assembly underwater repair work efficiency can be improved, the construction period can be shortened, the safety risk and the labor intensity can be reduced, the fuel operation precision and safety can be ensured. In addition, the nuclear fuel assembly underwater repair special simulation device replaces the original simulation nuclear fuel assembly, and each nuclear power plant unit can be mutually used, so that the risk that the simulation nuclear fuel assembly of each unit is damaged and cannot be used is eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the present application, the present application will be further described below in combination with the drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0029] Figure 1 is a structural schematic diagram of a simulation nuclear fuel assembly of related art;

[0030] Figure 2 is a structural schematic diagram of a guide pipe and a sleeve screw of a simulation nuclear fuel assembly of related art;

[0031] Figure 3 is a structural schematic diagram of a nuclear fuel assembly underwater repair special simulation device in some embodiments of the present application;

[0032] Figure 4 is a detail view of part A of the nuclear fuel assembly underwater repair special simulation device of Figure 3

[0033] is a detail view of part A of the nuclear fuel assembly underwater repair special simulation device of Figure 5 yes Figure 3 Detailed view of part B of the dedicated simulation device for underwater repair of nuclear fuel assemblies;

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

[0035] Figure 7 yes Figure 3 Detail of Section D of the specialized 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 and are constructed and operated in specific directions. They are only for the convenience of describing the technical solution and do not indicate that the devices or components referred to must have specific directions. Therefore, they should not be understood as limiting the present invention.

[0037] It should also be noted that, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", "fixed", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and 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 intervening 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 the indicated technical features. Therefore, the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of such 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, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, technologies, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0039] Referring now to the drawings, and more particularly to FIG. 1, a block diagram of a nuclear fuel assembly underwater repair special simulation device is shown, which is mainly applicable to the underwater repair project of defective nuclear fuel assemblies in pressurized water reactor nuclear power plants, and is used to verify whether the functions of the fuel assembly repair equipment meet the requirements and are available. The nuclear fuel assembly underwater repair special simulation device is used in cooperation with the fuel assembly repair equipment, the fuel plant crane, the new fuel hoist, and the fuel basket of the transmission pool tipping machine, and the size and function are matched with each other. Figure 3 Specifically, before the underwater repair of the defective fuel assembly in the nuclear power plant, the fuel assembly repair equipment is subjected to full-process operation practice and re-qualification test to determine whether the functions of the fuel assembly repair equipment meet the requirements for the underwater repair of the defective fuel assembly in the nuclear power plant. In this process, a group of the nuclear fuel assembly underwater repair special simulation devices are hoisted from the spent fuel pool to the new fuel hoist, the upper tube seat 1 underwater disassembly and assembly operation of the nuclear fuel assembly underwater repair special simulation device is performed, and after the simulation fuel rod is replaced, the nuclear fuel assembly underwater repair special simulation device is hoisted back to the spent fuel pool.

[0040] The appearance size of the nuclear fuel assembly underwater repair special simulation device is similar to that of the real fuel assembly, the weight of the nuclear fuel assembly underwater repair special simulation device is similar to or consistent with that of the real fuel assembly, and the outer size of the nuclear fuel assembly underwater repair special simulation device is 214 mm x 214 mm x 4060 mm. Of course, the outer size of the nuclear fuel assembly underwater repair special simulation device can be appropriately adjusted according to different real fuel assemblies, for example, the length size can be 200-220 mm, the width size can be 200-220 mm, and the height size can be 4000-4200 mm, which are not limited here.

[0041] As shown in FIG. 1, in some embodiments, the nuclear fuel assembly underwater repair special simulation device includes an upper tube seat 1, a lower tube seat 2, a connecting tube 3, an upper support plate 4, and a sleeve screw.

[0042] Figures 3 to 7

[0043] ​​The upper tube seat 1 simulates a real upper tube seat and is roughly square in shape, with a length and width of 214 mm. It may be equipped with a compression spring and other components. The lower tube seat 2 simulates a real lower tube seat and may also be equipped with a positioning pin hole and other components. The upper support plate 4 simulates a real mounting frame.

[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, such as stainless steel 304 or stainless steel 316L, or titanium alloy, which is not specifically limited here.

[0045] In some embodiments, an upper tube seat 1 and a lower tube seat 2 are respectively disposed at both ends of a connecting tube 3. The upper tube seat 1 is connected to one end of the connecting tube 3 via an upper support plate 4, and the other end of the connecting tube 3 is connected to the lower tube seat 2. The dedicated underwater repair simulation device for nuclear fuel assemblies also includes a plurality of guide tubes 5. The guide tubes 5 are disposed on the side of the upper support plate 4 facing 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. Sleeve screws are used to penetrate the through holes 111 to threadably engage the inner cavities of the guide tubes 5.

[0046] Among them, 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 and the upper support plate 4.

[0047] like Figure 1 It can be seen that the guide tubes of the simulated nuclear fuel assembly in the prior art are similar in size to the guide tubes of the real nuclear fuel assembly, with a length of nearly 4 meters, which makes the structure of the entire simulated nuclear fuel assembly complex, and the damage and wear of the guide tubes will affect the overall service life of the simulated nuclear fuel assembly. The guide tubes 5 of the present application are arranged on the upper support plate 4, and their length is smaller, which makes the overall structure of the special simulation device for underwater repair of nuclear fuel assemblies relatively simple, and the guide tubes 5 are not easily damaged or worn. Even if a part of the guide tubes 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 is relatively long, 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 set 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 is relatively short in length, and the sleeve screw directly cooperates with the guide tube 5, which is not easy to get stuck. Even if it gets stuck, the guide tube 5 and / or the sleeve screw can be easily handled, 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 operations. In addition, this 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 each unit's simulated nuclear fuel assembly 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. 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, or 80 mm. Preferably, the length of the guide tube 5 can be 67 mm. Compared to 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 make the replacement and disassembly of the guide tube 5 more convenient.

[0051] In some embodiments, the inner lumen of the guide tube 5 is internally threaded. 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, or 20 mm. Preferably, the axial length of the internal thread can be 17 mm, and the specification of the internal thread can be 17 mm M14×1 internal thread. Understandably, the relatively short axial length of the internal thread of the guide tube 5 ensures a secure fit with the sleeve screw while minimizing the length between the two, making it less likely to cause jamming.

[0052] Preferably, the guide tube 5 can be 67 mm long, and the inner cavity of the guide tube 5 can be 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, with a pitch of 1 mm. Sleeve screws of this specification are prone to jamming and blocking, making it impossible to disassemble and assemble the two. However, the guide tube 5 of the present application can be 67 mm long, 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 threadedly connected to the inner cavity of the guide tube 5, it is easier to disassemble and assemble, and is less likely to jam or block. This allows for quick assembly and disassembly of the upper tube seat 1 and the upper support plate 4, thereby effectively reducing the rapid assembly and disassembly of the entire nuclear fuel assembly underwater repair simulation device, effectively shortening the functional re-identification test time of defective fuel assembly equipment, and improving 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 underwater repair simulation device for 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 tube 3, respectively; the second flange 32 is detachably connected to the axial lower end of the connecting tube 3 and the lower tube seat 2, respectively. Preferably, the first flange 31, upper support plate 4, connecting tube 3, second flange 32, and lower tube seat 2 are 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 comprises a first body part 311 and a first cylindrical part 312, the first body part 311 is detachably connected with the upper support plate 4; the first cylindrical part 312 is arranged on the side of the first body part 311 away from the upper support plate 4, and the upper end of the connecting pipe 3 is threadedly connected with the inner cavity of the first cylindrical part 312. Specifically, the first body part 311 is generally in a plate structure, for example, a circular plate structure or a flat cylindrical structure, the first body part 311 is detachably connected with the upper support plate 4 through the first fastener 33, for example, a plurality of first connecting holes are arranged on the first body part 311, a plurality of second connecting holes are arranged on the upper support plate 4, and the first fastener 33 is sequentially arranged in the first connecting holes and the second connecting holes to connect and fix the first body part 311 and the upper support plate 4, thereby realizing the connection of the first flange 31 and the upper support plate 4. Preferably, the first fastener 33 includes but is not limited to a bolt or a screw. The upper end of the connecting pipe 3 is threadedly connected with the inner cavity of the first cylindrical part 312, for example, the upper end of the connecting pipe 3 is provided with an external thread surface, and the inner cavity of the first cylindrical part 312 is provided with an internal thread, and the two are threadedly connected and fixed. Preferably, the cross-sectional dimension of the first cylindrical part 312 can be smaller than the cross-sectional dimension of the first body part 311, for example, when the first body part 311 is a circular plate structure or a flat cylindrical structure, the first cylindrical part 312 is generally in a cylindrical structure, and the outer diameter of the first body part 311 can be greater than the outer diameter of the first cylindrical part 312, and the part of the first body part 311 located outside the first cylindrical part 312 is detachably connected with 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, for example, the first positioning hole 41 is arranged at the central position of the upper support plate 4. One side surface of the first body part 311 is provided with a first positioning part 313 matched with the first positioning hole 41, the first positioning part 313, the first body part 311 and the first cylindrical part 312 can be coaxially arranged, and the inner cavities of the three are in communication with each other, the first positioning part 313 can be in a cylindrical structure, and the outer diameter of the first positioning part 313 is less than or equal to the outer diameter of the first cylindrical part 312.

[0058] When the first flange 31 and the upper support plate 4 are assembled together, the first positioning part 313 can be first arranged in the first positioning hole 41 to realize positioning and pre-fixing, 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 part 313 and the first positioning hole 41 limit each other, which can improve the connection stability of the first flange 31 and the upper support plate 4.

[0059] The structure of the second flange 32 is introduced below, for example, 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 through 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, a circular plate-shaped structure or a flat cylindrical structure. The second main body 321 is detachably connected to the lower tube seat 2 via a 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. The second fastener 34 sequentially penetrates the third and fourth connection holes to connect and fix the second main body 321 to the lower tube seat 2, thereby achieving 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] Furthermore, the axial lower end of the connecting tube 3 is threadedly connected to 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-like structure or a flat cylindrical structure, the second cylindrical portion 322 is roughly cylindrical in shape, 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 portion of the second main body portion 321 located outside the second cylindrical portion 322 is detachably connected to the lower tube seat 2 via a second fastener 34.

[0062] Furthermore, the lower tube base 2 is provided with a second positioning hole 21, such as the second positioning hole 21 being provided at the center of the lower tube base 2. A second positioning portion 323 is provided on one side of the second main body portion 321 to cooperate with the second positioning hole 21. The second positioning portion 323, the second main body portion 321, and the second cylindrical portion 322 may be coaxially arranged, and the inner cavities of the three are interconnected. The second positioning portion 323 may 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, 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 , thereby reducing the assembly process.

[0066] In some embodiments, the connecting pipe 3 can be a segmented structure or a split structure to facilitate assembly and transportation, and can occupy less 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, which facilitates processing and production and improves the tolerance of assembly.

[0071] The upper end of the first sub-connecting pipe 3a is connected to the aforementioned first flange 31. The first sub-connecting pipe 3a can be threadedly fixed to the first flange 31, or the first sub-connecting pipe 3a can be integrally formed with the first flange 31. The lower end of the first sub-connecting pipe 3a is connected to the third flange 35. The lower end of the first sub-connecting pipe 3a can be threadedly fixed to the third flange 35, or the first sub-connecting pipe 3a can be integrally formed 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 fixed to the fourth flange 36 or the two can be integrally formed, and the lower end of the second sub-connecting pipe 3b can be threadedly fixed to the second flange 32 or the two can be integrally formed. 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 in 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 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 351; the third cylindrical portion 352, the third main body 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 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 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. 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, while 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 351 and the fourth main body 361 are connected by the 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 and the fifth cylindrical portion 362 are axially connected, and the sixth cylindrical portion 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 tube 3a, such as by having an internal thread within the inner cavity of the third cylindrical portion 352 and an external thread within the axial 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 axial upper end of the second sub-connecting tube 3b, such as by having an internal thread within the inner cavity of the sixth cylindrical portion 363 and an external thread within the axial upper end of the second sub-connecting tube 3b. The third main portion 351 and the fourth main portion 361 are connected by a third fastener 37 to connect the third flange 35 and the fourth flange 36, thereby connecting the first sub-connecting tube 3a and the second sub-connecting tube 3b, thereby achieving a coaxial arrangement between the first and second sub-connecting tubes 3a and 3b.

[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 body portion 351 and the fourth body portion 361 and sleeved around the outer periphery of the fourth tubular portion 353 and the fifth tubular portion 362. The third body portion 351, the middle support plate 6, and the fourth body portion 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, installed between the third main body 351 and the fourth main body 361, and is sleeved around the outer periphery of the fourth cylindrical portion 353 and the fifth cylindrical portion 362.

[0080] The third main body 351, the middle support plate 6, and the fourth main body 361 are connected by third fasteners 37, which simultaneously connect the third flange 35 and the fourth flange 36 and securely clamp the middle support plate 6. Because the middle support plate 6 is larger than the third flange 35 and the fourth flange 36, this detachable mounting method facilitates transportation and storage of the middle support plate 6, as well as 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 nuclear fuel assembly repair simulator also includes simulated fuel rods to simulate the gripping and insertion operations of real fuel rods. The simulated fuel rods can have the same shape and size as real fuel rods. Furthermore, the simulated fuel rods can be made of stainless steel or titanium alloy and can be solid rods.

[0083] In some embodiments, the dedicated simulation device for underwater repair of nuclear fuel assemblies further includes an installation tube 7, which is used for installing simulated fuel rods. The installation tube 7 is installed in the inner cavity of the connecting tube 3, and the installation 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 from 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 can be an integral structure, with the first flange being provided with a first limiting groove 31a for the upper end of the mounting tube to pass through, and the second flange being 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, and the second main body 321 is provided with a second limiting groove 32a. The upper end of the mounting tube 7 is located within the first limiting groove 31a, and the lower end of the mounting tube 7 is located within the second limiting groove 32a. The inner cavity of the fourth cylindrical portion 353 and the fifth cylindrical portion 362 is passed through the middle portion of the mounting tube 7, 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 portion 353, and the inner diameter of the inner cavity of the fifth cylindrical portion 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 production costs.

[0087] The upper end of the first sub-mounting tube 7a is located within the first limiting groove 31a, and the lower end of the first sub-mounting tube 7a is located within the inner cavity of the fourth cylindrical portion 353. The upper end of the second sub-mounting tube 7b is located within the inner cavity of the fifth cylindrical portion 362 and can abut against the lower end of the first sub-mounting tube 7a. 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 more securely installed.

[0088] like Figure 5 As shown, the dedicated underwater repair simulation device for nuclear fuel assemblies may further include an end plug 38 for sealing the inner cavity of the second flange 32. For example, the end plug 38 may seal the end of the sixth cylindrical portion 363. The end plug 38 may be located in the second positioning hole 21 and connected to the end of the second flange 32 via a fourth fastener 39. For example, the end plug 38 may be connected and fixed to the sixth cylindrical portion 363. 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, a bolt or screw. Of course, in some embodiments, the end 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, several 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 several limit blocks 8 are extended at intervals along the axial direction of 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. 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. 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, which facilitates the guidance of the mounting tube 7 to smoothly pass through the inner cavity of the limit block 8. Pre-selectively, the tapered grooves 81 are provided at both ends of the axial direction of the limit block 8, 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 spaced apart 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 mounting tube 7, so as to effectively support and effectively limit the mounting 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 preventing the installation tube 7 from deflecting and making the loading and unloading of the simulated fuel rods smoother. In addition, the limit block 8 can also serve 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, these 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, extraction 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 the underwater repair of defective fuel assemblies. It is mainly used for re-identification tests of defective fuel assembly repair equipment. The operation method includes: removing the sleeve screw of the upper tube seat 1, moving the upper tube seat 1, pulling out the simulated fuel rod, inserting the replacement fuel rod, reinstalling the upper tube seat 1, and reinstalling and locking the sleeve screw.

[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 replaces 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 methods 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, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of 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 further comprises a plurality of guide tubes (5), the guide tubes (5) being provided on a side of the upper support plate (4) away from the connecting tube (3), the upper tube seat (1) being provided with a plurality of through holes (111), the positions of the through holes (111) corresponding to the positions of the guide tubes (5), and the sleeve screws being used to penetrate the through holes (111) to be threadedly connected to the inner cavities of the guide tubes (5); The length of the guide tube (5) is 60-80 mm; 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); The second flange (32) is detachably connected to the axial lower end of the connecting pipe (3) and the lower pipe seat (2), respectively; The dedicated simulation device for underwater repair of nuclear fuel assemblies further comprises 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.

2. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 1, characterized in that: The first flange (31) comprises a first main body (311) and a first cylindrical portion (312), wherein the first main body (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 (311) facing 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 (321) and a second cylindrical portion (322), wherein the second main body (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 (321) facing away from the lower tube seat (2), and the lower end of the connecting pipe (3) is threadedly connected to the inner cavity of the second cylindrical portion (322).

3. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 1, 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), wherein the first sub-connecting pipe (3a) is arranged between the first flange (31) and the third flange (35), and both 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 both ends of the second sub-connecting pipe (3b) are respectively connected to the fourth flange (36) and the second flange (32).

4. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 3, 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); The third main body portion (351) and the fourth main body portion (361) are connected via 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) and the fifth cylindrical portion (362) are axially connected, and the sixth cylindrical portion (363) is threadedly connected to the upper end of the second sub-connecting tube (3b).

5. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 4, characterized in that: The nuclear fuel assembly underwater repair dedicated simulation device further comprises a middle support plate (6), the middle support plate (6) being installed between the third main body portion (351) and the fourth main body portion (361), and the middle support plate (6) being sleeved on the outer periphery of the fourth cylindrical portion (353) and the fifth cylindrical portion (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).

6. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 5, characterized in that: The first flange (31) is provided with a first limiting groove (31a) for the upper end of the mounting tube (7) to pass through, and the second flange (32) is provided with a second limiting groove (32a) for the lower end of the mounting tube (7) to pass through.

7. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 6, 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) 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 the lower end of the second sub-mounting tube (7b) is located in the second limiting groove (32a).

8. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 1, characterized in that: The dedicated simulation device for underwater repair of nuclear fuel assemblies also includes: A plurality of limit blocks (8), wherein the limit blocks (8) are sleeved on the mounting tube (7) and abut against the inner wall of the connecting tube (3).

9. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 8, characterized in that: A tapered groove (81) is provided at least at one end in the axial direction of the limit block (8), and the inner diameter of the tapered groove (81) gradually decreases from the axial end surface of the limit block (8) toward the middle of the limit block (8) to form a guide surface (811) on the inner wall surface of the limit block (8).

10. The dedicated simulation device for underwater repair of nuclear fuel assemblies according to claim 1, characterized in that: The dedicated simulation device for underwater repair of nuclear fuel assemblies further comprises an end plug for sealing the inner cavity of the second flange (32).

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