CN111095435B

CN111095435B - Fuel assembly transport container and bottom sealing device thereof

Info

Publication number: CN111095435B
Application number: CN201880058240.3A
Authority: CN
Inventors: 吴腾; 于久州; 刘广; 吴涛; 王超; 李其朋; 王弟东; 张春艳; 许骏翔
Original assignee: China General Nuclear Power Corp; China Nuclear Power Technology Research Institute Co Ltd; CGN Power Co Ltd
Current assignee: China General Nuclear Power Corp; China Nuclear Power Technology Research Institute Co Ltd; CGN Power Co Ltd
Priority date: 2018-11-26
Filing date: 2018-11-26
Publication date: 2023-08-25
Anticipated expiration: 2038-11-26
Also published as: WO2020107183A1; CN111095435A

Abstract

A fuel assembly (3) transport container and bottom seal (225) therefor, the bottom seal (225) comprising a lower cover (2251) for closing over the bottom of the transport container, and a clamping device (2252) mounted on the lower cover (2251). The clamping device (2252) comprises a clamping mechanism (2253) and an operating mechanism (2254), wherein the clamping mechanism (2253) comprises at least one clamping piece (2255) which is positioned on the inner side of the lower cover body (2251) and can reciprocate along the side surface of the lower cover body (2251) at a clamping position and a loosening position. The operating mechanism (2254) comprises an operating part (2260) for driving the clamping member (2255) to move towards a clamping position, when the clamping member (2255) is in the clamping position, the lower tube seat of the fuel assembly (3) in the transport container is clamped. The clamping device (2252) is arranged on the lower cover body (2251), so that the integrity of the edge of the lower cover body (2251) is ensured, the sealing problem of the cabin of the fuel assembly (3) is solved, and the tightness of the cabin of the fuel assembly (3) in the transportation process is ensured. The arc-shaped structure of the outer edge of the lower cover body (2251) improves safety, the fastening device is simple to operate, reliability is improved, the fastening of the base of the fuel assembly (3) is guaranteed, and the lower cover body (2251) is stressed more uniformly when impacted.

Description

Fuel assembly transport container and bottom sealing device thereof

Technical Field

The invention relates to the field of nuclear power, in particular to a fuel assembly transport container and a bottom sealing device thereof.

Background

The cabin bottom closing plate of the transport container of the related art nuclear fuel assembly has a recess on an outer edge thereof, into which the door and the boss pin are inserted in a closed position of the end plate of the door;

the bottom closing plate closes the end face of the fuel assembly compartment, the closing plate having an adjustable member holding the fuel assembly in the longitudinal direction of the container.

The disadvantages of the above product structure or technique are as follows:

1. the outer end of the sealing plate is provided with an oblong through hole, so that the strength of the sealing plate is weakened;

2. the outer end of the sealing plate is provided with a sunk groove surface, the processing technology is complex, and the processing precision is difficult to ensure;

3. the inner side of the sealing plate is provided with a plurality of locking sliding blocks and fastening screws, so that the operation time is long and the operation is complex in the locking process;

4. the outer edge of the sealing plate is a straight edge section, and under the impact working condition, the stress is uneven.

Disclosure of Invention

The invention aims to provide a fuel assembly transport container and a bottom sealing device thereof.

The technical scheme adopted for solving the technical problems is as follows: constructing a bottom sealing device of a fuel assembly transport container, comprising a lower cover body for sealing on the bottom of the transport container and a clamping device arranged on the lower cover body;

the clamping device comprises a clamping mechanism and an operating mechanism, wherein the clamping mechanism comprises at least one clamping piece which is positioned on the inner side of the lower cover body and can reciprocate along the side surface of the lower cover body at a clamping position and a loosening position;

the operating mechanism comprises an operating part for driving the clamping piece to move towards the clamping position, and the clamping piece clamps the fuel assembly lower tube seat in the transport container when in the clamping position.

Preferably, the operating mechanism includes a cam plate rotatably provided at one side of the lower cover, and the cam plate and the chucking member are located at the same side of the lower cover;

the cam disc edge is provided with an outwards protruding bulge, and the clamping piece is located the cam disc outer ring, so that when the operating part drives the cam disc to rotate, the bulge drives the clamping piece to move towards the clamping position.

Preferably, the edge of the cam disc is circumferentially provided with a plurality of protrusions, and the clamping pieces are circumferentially distributed on the outer ring of the cam piece and correspond to the positions of the protrusions;

the clamping device further comprises a plurality of reset pieces which are respectively propped against the clamping pieces, and the reset pieces provide elastic force for the clamping pieces to move towards the loosening position.

Preferably, the operating mechanism comprises an operating rod rotatably penetrating through the lower cover body, and the cam disc is arranged at one end of the operating rod;

the other end of the operating lever is provided with the operating part which is used for driving the operating lever to rotate after the tool is installed, and the cam disc is driven to rotate when the operating lever is rotated.

Preferably, a key groove is arranged at one end of the operating rod, which is used for installing the cam disc, a key is installed in the key groove, and a clamping groove clamped on the key is arranged on the cam disc.

Preferably, the operating mechanism further comprises a base plate, the clamping piece and the cam disc are arranged on one side, opposite to the lower cover body, of the base plate, and the base plate can move close to or far away from the lower cover body.

Preferably, the operating mechanism further comprises a fastening screw rod, the fastening screw rod is of a hollow structure, the fastening screw rod is in threaded connection with the lower cover body, and the operating rod penetrates through the fastening screw rod;

the base plate is arranged at the end part of the fastening screw, the fastening screw rotates on the lower cover body, the axial position is adjusted, and the base plate and the clamping piece are driven to be close to or far away from the lower cover body.

Preferably, the clamping mechanism further comprises a baffle plate covered on the clamping piece, and a bayonet which is used for the clamping piece to extend out after moving towards the clamping position is arranged on the baffle plate.

Preferably, the baffle is connected with the backing plate, and the clamping piece is positioned in a space formed by assembling the baffle and the backing plate.

A fuel assembly transport container comprising said bottom seal.

The fuel assembly transport container and the bottom sealing device thereof have the following beneficial effects: the clamping device is arranged on the lower cover body, so that the integrity of the edge of the lower cover body is ensured, the sealing problem of the cabin of the fuel assembly is solved, and the tightness of the cabin of the fuel assembly in the transportation process is ensured. The arc structure of the outer edge of the lower cover body improves safety, the fastening device is simple to operate, reliability is improved, fastening of the fuel assembly base is guaranteed, and the lower cover body is more uniformly stressed under the condition of being impacted. The clamping device can clamp the lower tube seat of the loaded fuel assembly, so that the fuel assembly is more stable in the transportation process.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic perspective view of a fuel assembly transport container in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of the support assembly of the fuel assembly transport container of FIG. 1 in an erected configuration;

FIG. 3 is a schematic view of the upper housing of FIG. 1 after being opened;

FIG. 4 is an exploded view of the fuel assembly transport container of FIG. 1;

FIG. 5 is a schematic cross-sectional view of the support assembly of FIG. 1;

FIG. 6 is a schematic cross-sectional view of a cushioning member of the cushioning structure of FIG. 5;

FIG. 7 is a schematic view of the support assembly of FIG. 4 with a cover plate flipped open;

FIG. 8 is a schematic cross-sectional view of the support assembly of FIG. 4;

FIG. 9 is a schematic cross-sectional view of the outer cover plate and the assembly on the outer cover plate of FIG. 8;

FIG. 10 is a schematic perspective view of the lower end cap of FIG. 4;

FIG. 11 is a schematic cross-sectional view of the lower end cap of FIG. 10;

FIG. 12 is a schematic perspective view of the flapper of FIG. 11 when opened;

fig. 13 is a perspective view of the upper end cap of fig. 4.

Detailed Description

For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings.

As shown in fig. 1 to 4, the fuel assembly transport container in a preferred embodiment of the present invention includes a housing 1 and a support structure 2 provided within the housing 1, the support structure 2 including a carrier 21, a support assembly 22.

The carrier 21 is mounted on the inner side of the housing 1, the support assembly 22 is mounted on the carrier 21, and two cavities 4 for accommodating and fixing the fuel assemblies 3 are formed in the support assembly 22, and the fuel assemblies 3 are generally in a columnar structure. The support assembly 22 can drive the fuel assembly 3 within the cavity 4 to be placed horizontally or to stand up.

The other end of the support member 22 is provided with a loading/unloading port, which is located at the upper end of the cavity 4 when the support member 22 is erected, and from which the fuel assembly 3 is inserted into the cavity 4 in the axial direction or removed from the cavity 4 in the axial direction.

A lower end cap 225 for positioning the fuel assembly 3 circumferentially is arranged at the end of the accommodating cavity 4 opposite to the loading and unloading port, and an upper end cap 222 for sealing the accommodating cavity 4 and positioning the fuel assembly 3 in the accommodating cavity 4 axially is arranged on the loading and unloading port.

The support assembly 22 can rotate under the action of the crane in a horizontal state and a vertical state, and when the support assembly 22 is in the vertical state, the fuel assembly 3 is conveniently vertically lifted into the accommodating cavity 4, and the support assembly 22 with the fuel assembly 3 is also conveniently rotated to the horizontal state. The loading process of the fuel assembly 3 is simpler and quicker, the loading efficiency is improved, and the fuel assembly 3 can be conveniently transported after the support assembly 22 and the fuel assembly 3 are placed horizontally at the same time and are contained in the transport container.

After the fuel assembly 3 is placed into the cavity 4, and prior to capping the upper end cap 222, the fuel assembly 3 is already positioned circumferentially to prevent rotation within the cavity 4. After the upper end cover 222 is covered, the fuel assembly 3 can be axially positioned, so that the longitudinal movement of the containing cavity 4 is prevented, the full constraint of the fuel assembly 3 is realized, the shaking in the containing cavity 4 in the transportation process is prevented, and the transportation safety and stability are improved.

As shown in fig. 5, in general, the housing 1 includes a lower case 11 and an upper case 12 mounted on an upper side of the lower case 11, and the lower case 11 and the upper case 12 are assembled to form a cylindrical structure with a horizontal axis, so that the housing is convenient to load and transport, and in this embodiment, the cylindrical structure is an octagon, and of course, the housing 1 may also have a square cylindrical structure with a horizontal axis.

The side walls of the lower shell 11 and the upper shell 12 are double-layer structures with hollow interlayers, so that the shell has higher impact resistance strength and excellent heat insulation, shock absorption and decontamination performances.

Preferably, the upper case 12 includes an upper outer case 122, an upper inner case 123, and upper end plates 124 provided at both ends, the upper outer case 122 and the upper inner case 123 being spaced apart from each other to form a double-layered structure with a hollow interlayer. The lower case 11 includes a lower outer case 112, a lower inner case 113, and lower end plates 114 provided at both ends, and the lower outer case 112 and the lower inner case 113 are spaced apart from each other to form a double-layered structure with a hollow interlayer.

The upper outer shell 122, the upper inner shell 123, and the lower outer shell 112 and the lower inner shell 113 are filled with heat insulating and shock absorbing materials. The heat-insulating and shock-absorbing material is filled between the double-layer structures, so that the influence of vibration and external impact generated when the container falls on the components in the container can be effectively reduced, and meanwhile, the conduction of heat to the inside of the shell during a fire working condition is reduced. The heat-insulating and shock-absorbing material can be filled into the polygonal double-layer structure of the upper shell and the lower shell after being molded, and the heat-insulating and shock-absorbing material has small volume and is easy to replace; while the container may contain multiple sets of fuel assemblies.

Further, the reinforcing ribs 13 are provided between the upper outer shell 122 and the upper inner shell 123, and between the lower outer shell 112 and the lower inner shell 113, so that the strength of the outer shell 1 can be improved, the deformation in the lifting and carrying process can be prevented, and the impact resistance can be improved.

As shown in fig. 2 to 4, in some embodiments, two ends of the upper housing 12 are respectively provided with a latch 121 protruding toward one side of the lower housing 11, and an inner side of an end surface of the lower housing 11 is provided with a slot 111 into which the latch 121 is engaged. The clamping tongue 121 comprises a steel plate and cork wrapped outside the steel plate, so that strength can be ensured, and the damping effect can be achieved.

When the upper housing 12 is mounted to the lower housing 11, the latch 121 is snapped into the catch 111, facilitating positioning therebetween. The end surfaces of the lower shell 11 and the upper shell 12 are polygonal, and after assembly, an eight-prismatic structure is formed, and flange edges for mutually locking and connecting the lower shell 11 and the upper shell 12 are respectively arranged on adjacent edges of the lower shell 11 and the upper shell 12. The edges of the upper shell 12 and the lower shell 11 are respectively provided with flange edges, so that the upper shell 12 and the lower shell 11 can be locked and fixed.

The two ends of the upper shell 12 are provided with hoisting structures for hoisting, and the hoisting structures are provided with first hoisting holes 125. The lower side of the lower housing 11 is provided with a leg, and the leg is provided with a first lifting hole 115 for lifting. The underside of the lower housing 11 is also provided with forklift apertures 116 for lifting up after insertion of the forklift. The lifting holes and the forklift holes 116 are arranged in multiple lifting modes, so that the lifting is more convenient.

As shown in fig. 2 to 6, a buffer structure 14 elastically connected to the lower case 11 is preferably provided at a side of the carrier 21, so that the carrier 21 is suspended in the lower case 11, and the suspension and elastic connection can reduce external impact to the carrier 21. The buffer structure 14 can absorb the impact transmitted from the housing 1 to the carrier 21, avoiding the impact on the fuel assembly 3.

In some embodiments, cushioning structure 14 includes a plurality of cushioning members 141 distributed across the sides of carrier 21 and connected to lower housing 11. The buffer members 141 serve as a shock absorbing device for absorbing shock of the fuel assembly to avoid the shock, and in general, the buffer members 141 are distributed on the longitudinal sides of the carrier 21, or the buffer members 141 may be distributed on each side.

The buffer 141 includes a shock absorbing body 1411 having elasticity, and top and bottom plates 1412 and 1413 provided at opposite ends of the shock absorbing body 1411. The top plate 1412 and the bottom plate 1413 are respectively provided with a first embedded part 1414 and a second embedded part 1415 embedded into the shock absorbing body 1411, and the first embedded part 1414 and the second embedded part 1415 are respectively provided with a back-off structure for preventing the shock absorbing body 1411 from falling off, so that the shock absorbing body 1411 is more firmly connected with the top plate 1412 and the bottom plate 1413.

The first embedded portion 1414 and the second embedded portion 1415 improve the shearing performance of the shock absorbing body 1411, so that the deformation of the shock absorbing body 1411 is smaller, and the service life is prolonged.

The top plate 1412 and the bottom plate 1413 are connected to the inner walls of the carrier 21 and the lower case 11, respectively, and fixedly connected to the carrier 21 and the lower case 11. The buffer body is clamped between the bearing frame 21 and the shell 1, and can play a role in buffering and preventing vibration. In other embodiments, the shock absorbing body 1411 may be a spring, a leaf spring, or the like.

The first embedded portion 1414 includes a first embedded section 1416 and a second embedded section 1417, which are sequentially connected, wherein one end of the first embedded section 1416, which is far away from the second embedded section 1417, is connected with the top plate 1412, and the second embedded section 1417 forms an inverted buckle to prevent the shock absorbing body 1411 from falling off.

In this embodiment, the first embedded section 1416 and the second embedded section 1417 are both cylindrical, and the cross-sectional shape of the second embedded section 1417 is larger than that of the first embedded section 1416, so that the step difference between the two sections forms an inverted buckle.

The shock attenuation body 1411 middle part is equipped with the connecting hole that runs through, and the connecting hole includes first hole section, second hole section, and the section size of second hole section is greater than the section size of first hole section. The first embedded section 1416 is inserted into the first hole section, and the second embedded section 1417 is positioned in the second hole section and embedded into the inner wall surface of the second hole section.

A bolt is screwed in the middle of the top plate 1412 and can be connected with the bearing frame 21 through the bolt. Preferably, the first embedded section 1416, the second embedded section 1417, the first hole section and the second hole Duan Tongzhou are arranged, so that the assembly and the positioning are facilitated, and the stress is more balanced.

The connecting hole is positioned in the middle of the shock absorption body 1411, and the connecting hole enables the middle of the shock absorption body 1411 to form a hollow structure, so that the weight of the shock absorption body 1411 is reduced, the materials are saved, and the shock absorption performance of the shock absorption body 1411 is improved.

The middle part of the bottom plate 1413 is provided with a through hole communicating with the second hole Duan Duiying, so that the connection hole communicates with the outside.

The second embedded portion 1415 comprises a third embedded section 1418 and a fourth embedded section 1419 which are sequentially connected, one end, far away from the fourth embedded section 1419, of the third embedded section 1418 is connected with the bottom plate 1413, and the fourth embedded section 1419 forms an inverted buckle to prevent the shock absorption body 1411 from falling off.

The third embedded section 1418 is cylindrical, and the fourth embedded section 1419 is conical. In other embodiments, the fourth embedded section 1419 may also be cylindrical, and have a cross-sectional dimension different from the cross-sectional dimension of the third embedded section 1418 to form the inverted buckle structure.

The first embedded portion 1414 and the second embedded portion 1415 may be distributed to include a plurality of sheet structures distributed along the circumferential direction, and the ends of the sheet structures are bent to form an inverted buckle.

The top plate 1412 and the bottom plate 1413 cover the end surfaces of the two ends of the damping body 1411 respectively, clamp the damping body 1411, and a plurality of connecting holes are distributed on the bottom plate 1413, and are connected and fixed with the shell 1 after penetrating the locking piece, so that the damping body is easy to assemble and disassemble.

The roof and the bottom plate are embedded in the shock absorption body 1411, so that the connection is firmer, the connection problem of the shock absorption body 1411 and the steel plate is solved, the shock absorption body 1411 made of steel roof, bottom plate and rubber material is firmer in connection, meanwhile, due to the fact that the steel lining plate is embedded in the shock absorption body 1411, the elasticity and the shearing performance of the shock absorption body 1411 are further improved, and the service life of the shock absorption body 1411 is prolonged.

Further, as shown in fig. 3, a supporting arm 23 is provided between the supporting member 22 and the carrier 21, so that the supporting member 22 can be supported when the supporting member 22 is vertically placed, and tilting is prevented during the process of loading the fuel assembly 3.

The support arm 23 is rotatably connected with the support assembly 22, a guide rail 211 arranged along the longitudinal direction is arranged on the bearing frame 21, the support arm 23 is in sliding fit with the guide rail 211, and one end of the guide rail 211 is provided with a clamping structure for clamping and positioning the support arm 23.

The engaging structure includes an engaging member swingably provided to the upper side of the guide rail 211, and an elastic member providing an elastic force to hold the engaging member at the upper side of the guide rail 211.

During erection of the support assembly 22, the support arm 23 moves over the rail 211 to press the catch against the rail 211. After the support assembly is erected, the support arm 23 is separated from the clamping piece, the clamping piece is reset to the upper side of the guide rail 211, and the clamping piece resists clamping of the support arm 23, so that the support assembly 22 is positioned, and the support assembly 22 is prevented from overturning downwards. After the fuel assembly 3 is assembled into the support assembly 22, the engagement members are then depressed below the rails 211, releasing the support arms 23 from the engagement members, allowing the support arms 23 to slide in opposite directions past the engagement members and into engagement with the underside of the support assembly 22.

As shown in connection with fig. 4, 5 and 7, in some embodiments, support assembly 22 includes a bracket 223 and an outer cover 224, an inner cover 227, and a lower end cap 225 that collectively define the cavity 4. Preferably, the support 223 extends in the longitudinal direction of the cavity 4, and the support 223 has a T-shaped cross section, including a bottom wall 2231 and a side wall 2232 disposed at one side of the bottom wall 2231.

The outer cover plate 224, the inner cover plate 227 and the side wall 2232 are located on the same side of the bottom wall 2231, the outer cover plate 224 and the side wall 2232 are far away from the outer edge of the bottom wall 2231 and are connected with two longitudinal edges of the bottom wall 2231, two accommodating cavities 4 for accommodating the fuel assemblies 3 are defined on two sides of the side wall 2232, and the outer cover plate 224 and the inner cover plate 227 are semi-circular in shape at the corresponding parts of the accommodating cavities 4.

The outer cover plate 224 with the arc-shaped structure can improve the stress intensity of the outer cover plate 224, is more stable when encountering rollover and falling impact, can avoid the impact, and protects the fuel assembly 3 inside. The outer cover 224 of the circular arc structure is compact and reduces the requirements for the external loading structure.

Preferably, each cavity 4 is provided with an outer cover 224, such that two sides of the outer cover 224 are connected to the side walls 2232 away from the outer edge of the bottom wall 2231 and to a longitudinal edge of the bottom wall 2231.

Meanwhile, the inner cover plate 227 is disposed in an angle formed by the bottom wall 2231 and the side wall 2232, and preferably, a pallet 228 for supporting the inner cover plate 227 is disposed in an angle formed by the bottom wall 2231 and the side wall 2232. The outer cover 224 and the inner cover 227 form a cylindrical structure, and define a cavity 4 for accommodating the fuel assembly 3 therein, and support the fuel assembly 3 from both sides.

The longitudinal edges of the outer cover 224 are rotatably connected with the bottom wall 2231 and the side walls 2232, so that the outer cover can be conveniently disassembled and assembled. Preferably, one side of the outer cover 224 is rotatably connected to the longitudinal side of the bottom wall 2231, the outer cover 224 is detachably connected to the outer side of the side wall 2232 away from the bottom wall 2231, and after the outer cover 224 is detached from the side wall 2232, the outer cover 224 is turned over to open the cavity.

The support assembly 22 has a simple structure, is convenient to assemble and disassemble and is convenient to operate. The complexity of the operation of the staff is reduced and reduced during the operation and maintenance process and during the loading and unloading of the fuel assembly.

For accommodating different numbers of fuel assemblies 3, the structure of the support 223 can be adjusted, so that the number of the cavities 4 on the support assembly 22 can be correspondingly adjusted, for example, only one group of outer cover plates 224 and inner cover plates 227 is arranged to form one cavity 4.

Referring to fig. 7, 8 and 9, the outer cover 224 is provided with a compressing structure 24 for compressing or releasing the fuel assembly in the cavity 4, after the fuel assembly is loaded into the cavity 4, the compressing structure 24 can compress the fuel assembly in the cavity 4, and when the fuel assembly needs to be taken out, the compressing structure 24 is released again, so that the fuel assembly can be taken out.

In some embodiments, the compressing structure 24 includes an adjusting member 241 penetrating the outer cover 224, and a compressing member 242 located inside the outer cover 224 and connected to the adjusting member 241, where the axial position of the adjusting member 241 is adjustable, and preferably, the adjusting member 241 is screwed with the outer cover 224 to drive the compressing member 242 to compress or loosen the fuel assembly 3. The adjusting piece 241 can also adjust the axial moving position under the drive of an external structure such as a motor.

The outer side of the outer cover 224 is provided with a semicircular arc-shaped supporting beam 2241 disposed along the circumferential direction, and the supporting beam 2241 includes one or more supporting beams for supporting the outer cover 224. When there are two or more support beams 2241, the support beams 2241 are arranged in the longitudinal direction of the chamber 4.

The inner side of the outer cover plate 224 is provided with a supporting frame for positioning and supporting the outer wall surface of the fuel assembly 3, one side of the supporting frame opposite to the accommodating cavity 4 is provided with a first supporting plate 2242, and the first supporting plate 2242 can perform pre-positioning on the fuel assembly 3 loaded in the accommodating cavity 4.

The first support plate 2242 is provided with an avoiding opening for the compressing member 242 to move toward the accommodating cavity 4, a certain space is reserved between the fuel assembly 3 and the first support plate 2242, the compressing member 242 can compress the fuel assembly 3, preferably, the width of the compressing member 242 is larger than that of the partition frame of the fuel assembly 3, so that the fuel assembly 3 can be compressed conveniently. During transportation, the transverse pressing piece 242 is in direct contact with the fuel assembly grid and presses the periphery of the fuel assembly, the main material is stainless steel, and a layer of rubber material with certain elasticity is paved on the contact surface of the pressing piece 242 and the grid.

The outer cover plate 224 is semi-circular arc, and two support frames are distributed along the circumference on the inner side of the outer cover plate 224, and each support frame extends along the longitudinal direction of the accommodating cavity 4. The inner side of the inner cover plate 227 is formed with two positioning surfaces perpendicular to each other, the positioning surfaces are provided with a second support plate 2243, and the two positioning surfaces and the two support frames form a square containing cavity 4 for positioning the two sides of the fuel assembly 3.

At least two groups of pressing structures 24 are arranged on the region of each supporting frame corresponding to the outer cover 224 along the longitudinal direction of the accommodating cavity 4. Preferably, the mounting location of the hold-down structure 24 corresponds to the location of the support beam 2241, allowing the support beam 2241 to provide support for the hold-down structure against deformation.

The first support plate 2242 includes an aluminum stainless steel plate, a rubber plate, and a base boron carbide plate, which are stacked, and at the same time, two positioning surfaces of the inner cover plate 227 are also covered with a second support plate 2243 made of the same material as the first support plate 2242. When the outer cover 224 is closed, the four aluminum-based boron carbide plates are in a cuboid shape in overall shape and are wrapped around the fuel assembly, but are not in contact with the fuel assembly, so that the whole length range of the fuel assembly is covered.

The aluminum-based boron carbide flat plate has stable irradiation resistance and excellent thermal neutron absorption performance, can maintain the subcritical state of the fuel assembly, and avoids radioactive pollution to the external environment. The aluminum-based boron carbide plate wraps the fuel assembly 3 from the periphery, and the fully-wrapped design can well absorb neutrons released by the fuel assembly 3, so that neutron escape space is reduced, and safety is guaranteed. The fully-coated design can resist high temperature and dust, is not easy to damage the fuel assembly 3, and has long service life.

The outer cover plate 224 can be turned over and opened, and the problem that the neutron absorption plate is difficult to install due to narrow space is solved, and the structure is relatively traditional, easy to clean and convenient to assemble and disassemble in the overhaul process.

Referring to fig. 10 to 12, a lower end cap 225 is mounted on the end of the support member 22 rotatably connected to the carrier 21, and covers the bottom end of the cavity 4 to serve as a bottom seal for the transport container of the fuel assembly 3.

Preferably, the lower end cap 225 includes a lower cap 2251 for capping the bottom of the shipping container, and a clamping device 2252 mounted on the lower cap 2251, the lower cap 2251 being detachably coupled to the bracket 223 and the outer cap 224.

The clamping device 2252 is mounted on the lower cover 2251, which ensures the integrity of the edge of the lower cover 2251, solves the sealing problem of the fuel assembly cabin, and ensures the tightness of the cabin during transportation of the fuel assembly. The arc-shaped structure of the outer edge of the lower cover 2251 improves safety, and the fastening device is simple to operate, improves reliability, ensures fastening of the fuel assembly base, and ensures that the lower cover 2251 is stressed more uniformly in an impacted state. The clamping device 2252 can clamp the bottom nozzle of the loaded fuel assembly so that the fuel assembly is more stable during transport. The clamping device 2252 is provided with a cam transmission mechanism, so that the simplicity and reliability of operation are further improved, and the processing is simpler.

The clamping device 2252 includes a clamping mechanism 2253 and an operating mechanism 2254, the clamping mechanism 2253 including a clamping member 2255 located inside the lower cover 2251 and reciprocally movable along the side of the lower cover 2251 between a clamped position and an undamped position.

The operating mechanism 2254 includes an operating portion 2260 for moving the clamping member 2255 to a clamping position, wherein the clamping member 2255 clamps the fuel assembly 3 down tube seat in the shipping container to prevent rotation of the fuel assembly 3 within the cavity 4.

The operating mechanism 2254 includes a lever 2256, a cam plate 2257, a backing plate 2258, and a fastening screw 2259, the lever 2256 rotatably penetrating the lower cover 2251, the cam plate 2257 being mounted at one end of the lever 2256 to rotate with the lever 2256.

The other end of the lever 2256 is provided with an operating portion 2260 for rotating the lever 2256 after the tool is installed, and for rotating the cam disk 2257 when the lever 2256 is rotated. In this embodiment, the operation portion 2260 is a square head for buckling with the operation wrench.

One end of the lever 2256, to which the cam disk 2257 is mounted, is provided with a key slot in which a key is mounted, and the cam disk 2257 is provided with a catch groove that catches on the key.

The cam plate 2257 is rotatably provided at one side of the lower cover 2251, and the cam plate 2257 and the clamping member 2255 are located at the same side of the lower cover 2251. The cam plate 2257 has protrusions 2261 protruding outward from the edge thereof, and the clamping members 2255 are located on the outer circumference of the cam plate 2257 such that when the operation part 2260 rotates the cam plate 2257, the protrusions 2261 move the clamping members 2255 to the clamping positions.

Preferably, cam disk 2257 has a plurality of protrusions 2261 circumferentially disposed about the periphery thereof, and clamping members 2255 circumferentially disposed about the outer periphery of the cam plate and corresponding to the location of each protrusion 2261. As cam disk 2257 rotates, protrusions 2261 each urge each clip member 2255 outward toward the clip position. The number of the clamping members 2255 may be one, and the lower tube holder of the fuel assembly 3 is clamped and fixed.

Further, the clamping members 2255 and the cam plate 2257 are disposed on a side of the backing plate 2258 opposite the lower cover 2251, and the backing plate 2258 is movable toward and away from the lower cover 2251, and the clamping members 2255 slidably engage the backing plate 2258. The bottom nozzle of the fuel assembly 3 may be abutted when the spacer 2258 is away from the bottom cover 2251. When the spacer 2258 approaches the lower cover 2251, it is released from the lower header of the fuel assembly 3.

Preferably, the fastening screw 2259 is a hollow structure, the fastening screw 2259 is screwed with the lower cover 2251, and the operating lever 2256 penetrates the fastening screw 2259. The backing plate 2258 is mounted at the end of the fastening screw 2259, and the fastening screw 2259 rotates on the lower cover 2251, adjusting the axial position, and driving the backing plate 2258 and the clamping member 2255 to approach or separate from the lower cover 2251.

In other embodiments, the rotation of the cam disk 2257 may be driven by a gear mechanism or the like, and the axial movement of the backing plate 2258 may be driven by a piston rod or the like.

The clamping device 2252 further includes a plurality of return members 2262 that respectively bear against each clamping member 2255, the return members 2262 providing a spring force to move the clamping members 2255 toward the release position.

The clamping mechanism 2253 further includes a catch 2263 that is capped onto the clamping member 2255, the catch 2263 having a bayonet 2264 for extending the clamping member 2255 after being moved to the clamping position. The clamping members 2255 include four members disposed at four inner corners of the baffle 2263. The baffle 2263 is connected to the spacer 2258, and the clamping member 2255 is located in a space formed by assembling the baffle 2263 and the spacer 2258. The shield 2263 may protect the clamping member 2255, the return member 2262, the backing plate 2258, etc., from damage during the clamping process.

Further, an end of the support member 22 opposite to the loading/unloading port is rotatably connected to the carrier 21 so as to enable the support member 22 to be horizontally placed or raised. Preferably, the lower cover 2251 is provided with a rotating portion 2265 for rotatably matching the support assembly 22 with the carrier 21, and the rotating portion 2265 may be a rotating shaft, a rotating hole, or both the rotating shaft and the rotating hole, so as to ensure that the lower cover 2251 can be rotatably matched with the carrier 21. In other embodiments, the bracket 223 may be rotatably engaged with the carrier 21.

In some embodiments, as shown in connection with fig. 13, the upper end cap 222 acts as a top closure for the shipping container of the fuel assembly 3, including a door panel for covering the upper end of the shipping container cavity 4, and a locking structure mounted on the door panel for axially locking the fuel assembly 3 within the shipping container.

The number of the door plates corresponds to that of the accommodating cavities 4, each door plate is detachably connected with the support 223, and each door plate covers one accommodating cavity 4. After the fuel assembly 3 is filled in one of the cavities 4, the filled fuel assembly 3 can be individually capped. Of course, the upper end cover 222 may be an integral structure, and can simultaneously open and close the loading and unloading ports corresponding to the cavities 4.

Further, each door panel is rotatably connected to the side wall 2232, and a locking structure 2222 on the door panel axially secures the installed fuel assembly 3. Meanwhile, each door plate is also rotatably connected with the bottom wall 2231, and the axial directions of the door plates, the side walls 2232 and the bottom wall 2231 are different, i.e., the door plates cannot rotate simultaneously. In other embodiments, each door panel may be rotatably coupled to only one of the side walls 2232 and the bottom wall 2231.

Preferably, the locking structure includes a first lock bar 2222 and a second lock bar 2223, the axial positions of which are adjustably mounted on the door panel, the first lock bar 2222 is located at the middle of the door panel and opposite to the central position of the upper tube seat of the fuel assembly 3, and the second lock bar 2223 includes a plurality of lock bars, and is centrally and symmetrically disposed around the first lock bar 2222. The first lock bar 2222 and the second lock bar 2223 can be respectively and independently adjusted, and can be used for pressing fuel assemblies without related assemblies and pressing fuel assemblies with related assemblies.

The first lock bar 2222 and the second lock bar 2223 are respectively screwed on the door plates, and the axial positions can be adjusted in a rotating way, so that the first lock bar 2222 and the second lock bar 2223 can tightly support and fix the lower tube seat. One end of the first lock bar 2222 and the second lock bar 2223 far away from the transport container accommodating cavity 4 is in threaded connection with an adjusting nut, and the adjusting nut is rotated to drive the first lock bar 2222 and the second lock bar 2223 to axially move to an adjusting position.

The ends of the first lock bar 2222 and the second lock bar 2223 opposite to the container holding cavity 4 are provided with soft buffer heads 2224, which can reduce the impact during fixing and prevent the damage of the lower tube seat. Preferably, the buffer head 2224 is a soft rubber pad that avoids snagging of the fuel assembly and associated assembly end surfaces during use.

Further, the ends of the first lock bar 2222 and the second lock bar 2223 opposite to the container cavity 4 are provided with the compression block 2225, which can increase the pressing area and increase the stability. The buffer head 2224 is mounted on the opposite side of the compression block 2225 from the cavity 4, and the buffer head 2224 is sleeved on the compression block 2225.

The upper tube seat of the fuel assembly 3 is provided with a pressing spring on a side opposite to the door panel, and the second lock lever 2223 is opposite to the pressing spring on the upper tube seat of the fuel assembly 3.

The top capping device comprises two mutually hinged door panels, each door panel is provided with a locking structure, and each door panel is respectively opposite to the containing cavity 4 for containing different fuel assemblies 3 in the transport container.

The locking structure 2222 comprises a locking rod which is in threaded connection with the locking hole and penetrates through the locking hole to be arranged towards the accommodating cavity 4, a baffle is usually arranged at the inner end of the locking rod, the axial position of the locking rod is adjusted, the baffle abuts against the fuel assembly 3, and therefore the fuel assembly 3 can be axially locked, and shaking in the axial direction is prevented.

In addition, if the lengths of the fuel assemblies 3 are different, after the fuel assemblies 3 are installed in the accommodating cavity 4, the fuel assemblies 3 with different lengths can be axially fixed by the lock rod.

Accordingly, a locking structure 2222 may also be provided on the lower cover 2251 to locate the ends of the fuel assembly 3.

It will be appreciated that the above technical features may be used in any combination without limitation.

The foregoing is only illustrative of the present invention and is not to be construed as limiting the scope of the invention, and all equivalent structures or equivalent flow modifications which may be made by the teachings of the present invention and the accompanying drawings or which may be directly or indirectly employed in other related art are within the scope of the invention.

Claims

1. A bottom sealing device for a fuel assembly transport container, comprising a lower cover (2251) for closing over the bottom of the transport container, and a clamping device (2252) mounted on the lower cover (2251);

the clamping device (2252) comprises a clamping mechanism (2253) and an operating mechanism (2254), wherein the clamping mechanism (2253) comprises at least one clamping piece (2255) which is positioned on the inner side of the lower cover body (2251) and can reciprocate along the side surface of the lower cover body (2251) at a clamping position and at a loosening position, and a cam disk (2257); the cam plate (2257) is rotatably disposed at one side of the lower cover (2251), and the cam plate (2257) and the retainer (2255) are located at the same side of the lower cover (2251);

the operating mechanism (2254) comprises an operating part (2260) for driving the clamping piece (2255) to move towards the clamping position, and an operating rod (2256) rotatably penetrating the lower cover body (2251), wherein the clamping piece (2255) clamps the lower tube seat of the fuel assembly (3) in the transport container when at the clamping position; -said cam disc (2257) is mounted at one end of said lever (2256); the other end of the operating rod (2256) is provided with the operating part (2260) for driving the operating rod (2256) to rotate after the tool is installed, and driving the cam disc (2257) to rotate when the operating rod (2256) is rotated;

the cam disc (2257) edge is equipped with outwards convex protruding (2261), chucking spare (2255) are located cam disc (2257) outer lane, in order when operating means (2260) drive cam disc (2257) rotate, protruding (2261) drive chucking spare (2255) to chucking position removal.

2. The bottom seal of a fuel assembly transport container of claim 1, wherein the cam plate (2257) has a plurality of protrusions (2261) circumferentially distributed around an edge thereof, and the retainer (2255) is circumferentially distributed around an outer periphery of the cam plate (2257) and corresponds to a location of each of the protrusions (2261);

the clamping device (2252) further comprises a plurality of return members (2262) respectively abutting each clamping member (2255), the return members (2262) providing an elastic force to the clamping members (2255) to move to the release position.

3. The bottom seal of a fuel assembly transport container of claim 1, wherein said lever (2256) has a keyway at an end where said cam plate (2257) is mounted, a key is mounted in said keyway, and a catch groove is provided on said cam plate (2257) that snaps onto said key.

4. The bottom seal of a fuel assembly transport container of claim 1, wherein the operating mechanism (2254) further comprises a backing plate (2258), the clamping member (2255), cam plate (2257) being disposed on a side of the backing plate (2258) opposite the lower cover (2251), the backing plate (2258) being movable toward and away from the lower cover (2251).

5. The bottom sealing device of a fuel assembly transport container according to claim 4, wherein the operating mechanism (2254) further comprises a fastening screw (2259), the fastening screw (2259) being of hollow structure, the fastening screw (2259) being screwed with the lower cover (2251), the operating lever (2256) passing through the fastening screw (2259);

the base plate (2258) is installed at the end part of the fastening screw (2259), the fastening screw (2259) rotates on the lower cover body (2251), the axial position is adjusted, and the base plate (2258) and the clamping piece (2255) are driven to be close to or far away from the lower cover body (2251).

6. The bottom seal of a fuel assembly transport container of claim 5, wherein the clamping mechanism (2253) further comprises a shield (2263) covering the clamping member (2255), the shield (2263) being provided with a bayonet (2264) for the clamping member (2255) to extend beyond the clamping position.

7. The bottom seal of a fuel assembly transport container of claim 6, wherein said baffle (2263) and said gasket (2258) are connected, and said clip (2255) is located in a space formed by assembly of said baffle (2263) and gasket (2258).

8. A fuel assembly transport container comprising the bottom sealing arrangement of any one of claims 1 to 7.