High-burn-up spent fuel storage and transportation dual-purpose sealed container

Abstract

The invention provides a high-burn-up spent fuel storage and transportation dual-purpose sealed container which comprises a barrel and a fuel basket, and a limiting supporting assembly is arranged on the inner wall of the barrel in the axial direction of the barrel; the fuel basket is arranged in the barrel in a penetrating mode in the axial direction of the barrel and matched with the limiting and supporting assembly. The outer peripheral side of the fuel basket and the inner wall of the barrel are in clearance fit and communicated with each other. According to the dual-purpose sealed container for storage and transportation of the high-fuel-consumption spent fuel, the fuel basket is integrally arranged, the cylinder supports the fuel basket through the axial limiting supporting assembly instead of being provided with a plurality of supporting plates in the axial direction of the fuel basket, and therefore the maximum capacity of the fuel basket is facilitated in the storage stage; a single sealed container can be used for loading more fuel assemblies so as to improve the economical efficiency and meet the transportation requirement; the peripheral side of the fuel basket is in clearance fit with the inner wall of the barrel, so that good natural circulation convection heat transfer performance of the sealed container is guaranteed, decay heat of high-burn-up spent fuel can be effectively transferred to the outer wall of the sealed container, and it is guaranteed that the temperature of a fuel cladding is below a limit value.

Description

Technical Field

[0001] The invention relates to the technical field of spent fuel storage and transportation, and in particular to a sealed container for storing and transporting high-burnup spent fuel. Background Art

[0002] Pressurized water reactor nuclear power plants use the heat generated by the fission of nuclear fuel assemblies to generate nuclear power. As the fission elements in the fuel assemblies are consumed, the reactor needs to be refueled at regular intervals.

[0003] The common refueling cycle is 12 to 18 months. During each refueling operation, about 1 / 3 of the fuel assemblies will be unloaded from the reactor as spent fuel and transferred to the spent fuel pool of the nuclear power unit for storage.

[0004] The conventional design life of a pressurized water reactor nuclear power plant is 40 to 60 years, but the capacity of the spent fuel pool is limited and can generally only meet the spent fuel storage needs for more than 10 years. Problems related to the full capacity of the spent fuel pool are bound to arise during the life of the nuclear power plant.

[0005] In this context, the existing technical measures to alleviate the problem of spent pool fullness in nuclear power plants mainly include:

[0006] 1. Increase the storage capacity of the spent fuel pool.

[0007] The main technical solutions include using the surplus space in the spent fuel pool to add spent fuel storage racks; or replacing the existing spent fuel storage racks, replacing non-intensive storage racks with intensive storage racks, so as to achieve the purpose of storing more spent fuel assemblies per unit area.

[0008] 2. Transfer of spent fuel between units.

[0009] A nuclear power plant often has multiple nuclear power units, and each nuclear power unit is often built in batches. The time for completion, commissioning and grid-connected power generation varies. The spent fuel of the old unit can be introduced into the spent fuel storage pool of the new unit to alleviate the problem of the old unit's spent fuel pool being full.

[0010] 3. Construct intermediate storage facilities.

[0011] Although improving the storage capacity of the spent fuel pool and transferring spent fuel between units can alleviate the problem of spent fuel pool fullness to a certain extent, the degree of relief is limited and can only delay the time when the spent fuel pool is full, but cannot completely solve the problem.

[0012] In this case, building an intermediate storage facility is a safe, economical, efficient and flexible option to solve the problem of full capacity of spent pools. There are two technical routes for intermediate storage facilities: metal container type and sealed container with concrete module / concrete container. The two are equally safe, but the latter has more advantages in terms of economy. Currently, intermediate storage facilities at home and abroad generally adopt the technical route of sealed container with concrete module or concrete container.

[0013] At present, the fuel closed cycle strategy is generally implemented. The spent fuel assemblies of pressurized water reactor nuclear power plants will be transported to spent fuel reprocessing plants to extract useful nuclides in the spent fuel assemblies for secondary utilization. Therefore, if the sealed containers used in the spent fuel intermediate storage facilities can have both storage and off-site transportation functions, it will greatly improve the convenience of subsequent operations related to the outbound transportation to the spent fuel processing plant, avoiding the cumbersome process operations such as the spent fuel re-entering the water, opening the cans to take out the materials, and then re-canning and sealing. However, the transportation of spent fuel outside the plant must comply with standards such as GB 11806 "Regulations on the Transportation of Radioactive Materials", and must be able to withstand the superposition of accident conditions such as 9m drop, 1m puncture, 800℃ fire for 30min, and maintain structural safety, criticality safety, shielding safety, thermal safety, tolerance of radioactive materials, and the retrievability of spent fuel contents. Its design requirements are much higher than those of spent fuel sealed containers that only need to meet the storage function.

[0014] That is, the traditional storage and transportation of spent fuel has the following problems:

[0015] 1. The connection between the intermediate storage and off-site transportation of spent fuel has not been fully considered.

[0016] According to the current nuclear fuel closed cycle strategy, all spent fuel must eventually be shipped to the reprocessing plant, and the intermediate storage of spent fuel is only an intermediate transition state. The spent fuel retrieval of some dry storage technologies requires the sealed container to be opened, and the fuel assembly to be transported back to the spent pool, and then loaded into off-site transport containers for external transportation. This technical route is cumbersome to operate, and requires the spent fuel pool to be decommissioned only after the intermediate storage facility is decommissioned, which greatly increases the operation and maintenance costs of the spent fuel pool of the nuclear power plant and affects the overall decommissioning of the nuclear power unit.

[0017] 2. Poor economic efficiency.

[0018] Some spent fuel storage and transportation technical routes adopt the technical solution of dual-purpose metal storage and transportation containers, that is, the spent fuel is stored in metal storage and transportation containers, and is sealed with a bolt compression structure and a metal sealing ring; when the intermediate storage is carried out in the plant, the loaded dual-purpose metal storage and transportation containers can be placed in the plant for intermediate storage. When it is necessary to transport it outside the plant, shock absorbers can be installed at both ends of the container for transportation outside the plant. This technical solution has good operational convenience, but the metal storage and transportation dual-purpose containers are expensive and will impose a very high economic burden on nuclear power owners. At the same time, it is necessary to consider the lightweight of the sealed container. When the lifting capacity of the fuel plant hoisting equipment is fixed, the lightweight of the sealed container is conducive to improving its loading capacity, thereby improving the economy of the technical solution.

[0019] 3. Unable to meet the requirements of high burnup spent fuel assemblies.

[0020] The future development trend is to make full use of the value of fuel and unload the nuclear fuel assembly after the fuel has been burned up to a sufficient depth. The current mainstream third-generation nuclear power technology is high-burnup spent fuel assembly. However, many current spent fuel storage and transportation technologies can only meet the storage and transportation needs of medium-burnup assemblies or low-burnup assemblies, but it is difficult to meet the storage and transportation needs of high-burnup assemblies. High-burnup assemblies have the characteristics of large radiation doses and high decay heat power, and have more stringent restrictions on safety limits such as thermal engineering.

[0021] Based on this, the inventor of the present application proposes a sealed container for storing and transporting high-burnup spent fuel, in order to solve at least one of the above-mentioned technical problems. Summary of the invention

[0022] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the connection between intermediate storage and off-site transportation of spent fuel is not fully considered, and to provide a high-burnup spent fuel storage and transportation dual-purpose sealed container.

[0023] The present invention solves the above technical problems through the following technical solutions:

[0024] The present invention provides a high-burnup spent fuel storage and transportation dual-purpose sealed container, which is characterized in that it includes:

[0025] The inner wall of the cylinder is provided with a limited support assembly along its axial direction;

[0026] The fuel basket is arranged inside the cylinder along the axial direction of the cylinder and cooperates with the limit support assembly; wherein,

[0027] The outer peripheral side of the fuel basket and the inner wall of the cylinder are gap-matched and communicated with each other.

[0028] According to one embodiment of the present invention, the limit support assembly includes a plurality of angle limit supports and a plurality of line limit supports;

[0029] The angular limit supports and the linear limit supports are both extended along the axial direction of the cylinder, and a plurality of the angular limit supports and a plurality of the linear limit supports are arranged at intervals.

[0030] According to an embodiment of the present invention, ventilation holes are respectively formed on the top and the bottom of the fuel basket, and the ventilation holes extend radially along the cylinder.

[0031] According to one embodiment of the present invention, the fuel basket includes a plurality of spliced ​​storage cavity assemblies, and the storage cavity assemblies are welded via connecting plates.

[0032] According to one embodiment of the present invention, the storage cavity assembly is divided into a plurality of first storage cavity assemblies, a plurality of second storage cavity assemblies and a plurality of third storage cavity assemblies;

[0033] A plurality of the first storage cavity components are arranged in a cross shape, a plurality of the second storage cavity components are arranged around the first storage cavity component, and a plurality of the third storage cavity components are arranged around the second storage cavity component;

[0034] The fuel basket is formed by sequentially welding the first storage cavity assembly, the second storage cavity assembly, and the third storage cavity assembly.

[0035] According to one embodiment of the present invention, the connecting plate comprises a plurality of first connecting plates, a plurality of second connecting plates, a plurality of third connecting plates and a plurality of fourth connecting plates;

[0036] Adjacent first storage cavity components are connected via the first connecting plate, the first storage cavity component and the second storage cavity component are connected via the first connecting plate and the second connecting plate, the third storage cavity component and the first storage cavity component are connected via the second connecting plate and the third connecting plate, and the third storage cavity component and the second storage cavity component are connected via the second connecting plate and the fourth connecting plate; wherein,

[0037] The first connecting plate is welded to the first storage cavity assembly along the axial direction of the storage cavity assembly, the second connecting plate is welded to the adjacent storage cavity assemblies at both ends of the adjacent storage cavity assemblies, and the third connecting plate and the fourth connecting plate are welded to the adjacent storage cavity assemblies along the axial direction of the storage cavity assembly.

[0038] According to one embodiment of the present invention, the first connecting plate is connected to the storage chamber assembly by laser welding, the second connecting plate is connected to the storage chamber assembly by argon arc welding, and the third connecting plate and the fourth connecting plate are connected to the storage chamber assembly by profile welding or argon arc welding; wherein,

[0039] The fourth connecting plate is flush with the outer end surface of the storage chamber assembly, and the first connecting plate, the second connecting plate and the third connecting plate are recessed in the plane of the adjacent outer end surface of the storage chamber assembly.

[0040] According to one embodiment of the present invention, the storage chamber assembly includes a tube body, a neutron absorption plate and a cladding;

[0041] The neutron absorption plate is arranged on the outer peripheral side of the tube body, the cladding cover is arranged on the outer side of the neutron absorption plate, and the cladding is provided with anti-impact blocks at both ends along the axial direction of the tube body, and an expansion gap is left between the cladding and the anti-impact blocks.

[0042] According to one embodiment of the present invention, the cylinder and the cladding are made of 316 stainless steel;

[0043] The material of the neutron absorption plate is aluminum-based boron carbide.

[0044] According to one embodiment of the present invention, a top cover is further provided on the top of the cylinder, a ventilation channel and a drainage channel are provided on the top cover, and sealing rings are provided on the tops of the ventilation channel and the drainage channel;

[0045] The ventilation channel and the drainage channel are provided with shielding blocks facing the cylinder.

[0046] According to an embodiment of the present invention, the ventilation channel and the drainage channel are both ventilated and drained through quick connectors, and the top cover is used to seal the ventilation channel and the drainage channel after ventilation and drainage.

[0047] According to an embodiment of the present invention, the ventilation channel and the drainage channel are disposed through the shielding block, and the middle portions of the ventilation channel and the drainage channel are bent.

[0048] According to one embodiment of the present invention, a single fault protection lug is also provided on the top cover.

[0049] According to an embodiment of the present invention, a drainage groove is provided at the bottom of the cylinder.

[0050] The positive and progressive effects of the present invention are:

[0051] In the high-burnup spent fuel storage and transportation dual-purpose sealed container of the present invention, the fuel basket is arranged in an integrated manner, and the cylinder supports the fuel basket with an axial limit support assembly, rather than arranging multiple support plates along the axial direction of the fuel basket. This is conducive to maximizing the capacity of the fuel basket during the storage stage, and a single sealed container can load more fuel assemblies to improve economy and meet transportation requirements;

[0052] In addition, the gap between the outer peripheral side of the fuel basket and the inner wall of the cylinder ensures good natural circulation convection heat transfer performance of the sealed container, which can effectively transfer the decay heat of high-burnup spent fuel to the outer wall of the sealed container, ensuring that the temperature of the fuel cladding is below the limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0054] Figure 1 It is a cross-sectional view of the sealed container for storage and transportation of high-burnup spent fuel of the present invention;

[0055] Figure 2 for Figure 1 sectional view of;

[0056] Figure 3 This is a front view of the sealed container for storing and transporting high-burnup spent fuel according to the present invention;

[0057] Figure 4 is a cross-sectional view of the cylinder of the present invention;

[0058] Figure 5 This is a front view of the sealed container for storing and transporting high-burnup spent fuel according to the present invention;

[0059] Figure 6 It is a schematic diagram of the arrangement of the fuel basket of the present invention;

[0060] Figure 7 It is a structural schematic diagram of a state of the storage chamber assembly of the fuel basket of the present invention;

[0061] Figure 8 It is a structural schematic diagram of another state of the storage chamber assembly of the fuel basket of the present invention;

[0062] Fig. 9 is a cross-sectional view of a storage chamber assembly of the present invention;

[0063] Fig.10 It is a schematic diagram of the structure of the top cover of the present invention;

[0064] Fig.11 is a top view of the top cover of the present invention;

[0065] Fig.12 for Fig.11 Sectional view of AA in the middle;

[0066] Fig.13 for Fig.12 Cross-sectional view of BB.

[0067] 1. Cylinder; 11. Limit support assembly; 12. Angle limit support; 13. Line limit support; 14. Top cover; 141. Ventilation channel; 142. Drainage channel; 143. Sealing ring; 144. Shielding block; 145. Single fault protection lifting lug;

[0068] 2. Fuel basket; 21. Ventilation hole; 22. Storage chamber assembly; 221. First storage chamber assembly; 222. Second storage chamber assembly; 223. Third storage chamber assembly; 23. Connecting plate; 231. First connecting plate; 232. Second connecting plate; 233. Third connecting plate; 234. Fourth connecting plate; 24. Tube; 25. Neutron absorption plate; 26. Cladding; 27. Anti-impact stopper; 28. Expansion gap. DETAILED DESCRIPTION

[0069] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0071] Figures 1 to 13 The present invention proposes a sealed container for storage and transportation of high-burnup spent fuel, comprising a cylinder 1 and a fuel basket 2. A limited support assembly 11 is arranged on the inner wall of the cylinder 1 along its axial direction; the fuel basket 2 is penetrated into the cylinder 1 along the axial direction of the cylinder 1 and cooperates with the limited support assembly 11; wherein the outer peripheral side of the fuel basket 2 is gap-matched with the inner wall of the cylinder 1 and is connected to each other.

[0072] The traditional fuel basket 2 is connected to the cylinder 1 along its axial direction through multiple support plates, and the fuel assemblies are inserted through the holes on the support plates. The support plates themselves occupy too much space and the fuel basket is easily deformed during transportation. This method is not conducive to heat dissipation and maximum loading.

[0073] In the present invention, the fuel basket 2 is integrally arranged and axially penetrates the cylinder 1, and the limit support assembly 11 is arranged on the cylinder 1 to support the fuel assembly. In this way, on the one hand, the traditional support plate is eliminated, and the amount of fuel basket 2 that can be loaded is increased; on the other hand, the fuel basket 2 has a stronger integrity, and can still maintain the storage cavity spacing under accident transportation conditions such as a 9m drop during off-site transportation, thereby improving the transportation stability of the sealed container.

[0074] At the same time, the outer peripheral side of the fuel basket 2 is gap-matched with the inner wall of the cylinder 1 and is connected to each other, forming a connected heat dissipation space on the outer peripheral side of the fuel basket 2, which is conducive to conducting the heat generated by the fuel in the fuel basket 2 to the cylinder 1, and then from the cylinder 1 to the outside.

[0075] Please refer to Figures 1 to 4 The limiting support assembly 11 includes a plurality of angular limiting supports 12 and a plurality of linear limiting supports 13; the angular limiting supports 12 and the linear limiting supports 13 are both axially extending along the cylinder 1 and the plurality of angular limiting supports 12 and the plurality of linear limiting supports 13 are spaced apart.

[0076] The corner limit supports 12 and the line limit supports 13 can prevent the fuel basket 2 from rotating and translating during transportation, thereby ensuring the stability of transportation.

[0077] Because the cross-sectional shape of the cylinder 1 along its axial direction is circular, and the cross-sectional shape of the storage cavity of the fuel basket 2 along its axial direction is rectangular. Therefore, the outer periphery of the fuel basket 2 has an angle between a plane and an adjacent surface. In order to ensure the support stability of the cylinder 1 to the fuel basket 2, the limiting support assembly 11 is divided into an angle limiting support 12 and a line limiting support 13. The angle limiting support 12 is used to clamp the angle of the outer periphery of the fuel basket 2, and the line limiting support 13 is used to abut the surface of the outer periphery of the fuel basket 2. Therefore, the angle limiting support 12 and the line limiting support 13 cooperate with each other to ensure the support stability of the fuel basket 2.

[0078] The sealed container of the present invention eliminates the traditional support plate, thereby expanding the available space in the cylinder 1 and further increasing the capacity of the fuel basket 2.

[0079] Moreover, the support plate will hinder the heat conduction between the fuel basket 2 and the cylinder 1. In the present invention, the outer peripheral side of the fuel basket 2 and the inner wall of the cylinder 1 are gap-matched and connected to each other, so a connected space is formed at the periphery of the fuel basket 2, thereby effectively transferring the decay heat of the high-burnup spent fuel to the outer wall of the sealed container, ensuring that the temperature of the spent fuel shell is below the limit.

[0080] Furthermore, ventilation holes 21 are respectively formed at the top and the bottom of the fuel basket 2 , and the ventilation holes 21 extend radially along the cylinder 1 .

[0081] The provision of the ventilation holes 21 is conducive to further increasing the space between the top and bottom of the fuel basket 2 and the cylinder 1, thereby increasing the air circulation space between the fuel basket 2 and the cylinder 1, improving the natural circulation convection heat transfer performance of the fuel basket 2, and effectively transferring the decay heat of high-burnup spent fuel to the outer wall of the sealed container.

[0082] In one embodiment, the fuel basket 2 includes a plurality of spliced ​​storage cavity assemblies 22 , and the storage cavity assemblies 22 are welded via connecting plates 23 .

[0083] In the conventional cylinder 1, a plurality of support plates are arranged at intervals along the axial direction thereof, and a plurality of holes are opened on the support plates, and the storage cavity assembly 22 is penetrated in the holes. On the one hand, the overall structural strength of the fuel basket 2 is poor, which is not conducive to transportation. On the other hand, the efficiency is very low when assembling with the cylinder 1, and the storage cavity spacing cannot be guaranteed under accidental transportation conditions such as a 9m drop during transportation outside the factory.

[0084] The fuel basket 2 of the present invention is integrally arranged and is welded from a plurality of storage cavity assemblies 22, and adjacent storage cavity assemblies 22 are welded via connecting plates 23, so that the fuel basket 2 can be separately processed and formed on the outside of the cylinder 1, and then integrally loaded into the cylinder 1, thereby improving the loading efficiency and greatly improving the connection stability between the fuel basket 2 and the cylinder 1, thereby meeting the transportation requirements.

[0085] Please refer to Figure 5 and Figure 6 The storage chamber assembly 22 is divided into a plurality of first storage chamber assemblies 221, a plurality of second storage chamber assemblies 222, and a plurality of third storage chamber assemblies 223; the plurality of first storage chamber assemblies 221 are arranged in a cross shape, the plurality of second storage chamber assemblies 222 are arranged around the first storage chamber assemblies 221, and the plurality of third storage chamber assemblies 223 are arranged around the second storage chamber assemblies 222. The fuel basket 2 is formed by welding the first storage chamber assembly 221, the second storage chamber assembly 222, and the third storage chamber assembly 223 in sequence.

[0086] The fuel basket 2 of the present invention is processed and formed from the inside out, and a plurality of storage cavity components 22 are processed and formed in advance, thereby facilitating assembly and disassembly with the cylinder 1 and improving the assembly and disassembly efficiency of the fuel basket 2 and the cylinder 1 .

[0087] Further, the connecting plate 23 includes a plurality of first connecting plates 231, a plurality of second connecting plates 232, a plurality of third connecting plates 233 and a plurality of fourth connecting plates 234; adjacent first storage cavity components 221 are connected via the first connecting plate 231, the first storage cavity component 221 and the second storage cavity component 222 are connected via the first connecting plate 231 and the second connecting plate 232, the third storage cavity component 223 and the first storage cavity component 221 are connected via the second connecting plate 232 and the third connecting plate 233, and the third storage cavity component 223 and the second storage cavity component 222 are connected via the second connecting plate 232 and the fourth connecting plate 234; wherein, the first connecting plate 231 and the first storage cavity component 221 are welded axially along the storage cavity component 22, the second connecting plate 232 is welded to the adjacent storage cavity component 22 at both ends of the adjacent storage cavity component 22, and the third connecting plate 233 and the fourth connecting plate 234 are welded to the adjacent storage cavity component 22 along the axial direction of the storage cavity component 22.

[0088] Reference Figure 2 and Figure 6 The present invention adopts a 3-5-5-5-3 type fuel basket 2 arrangement structure, corresponding to the numbers 1-21 in the figure.

[0089] Specifically, numbers 2, 6, 9, 10, 11, 12, 13, 16, and 20 are first storage chamber assemblies 221 , numbers 5, 7, 15, and 17 are second storage chamber assemblies 222 , and numbers 1, 3, 4, 8, 14, 18, 19, and 21 are third storage chamber assemblies 223 .

[0090] The connecting plate 23 corresponds to type a, type b, type c, and type d in the figure.

[0091] That is, adjacent first storage cavity assemblies 221 are connected by a type A first connecting plate 231, and there is sufficient space at the opposite ends of the first connecting plate 231, so the two ends of the first connecting plate 231 are laser welded along the axial direction of the first storage cavity assembly 221, thereby improving the connection stability between the first storage cavity assemblies 221.

[0092] After the first storage cavity assembly 221 is welded, the second storage cavity assembly 222 is welded to the first storage cavity assembly 221 , and is specifically connected to the first storage cavity assembly 221 through the first connecting plate 231 and the second connecting plate 232 .

[0093] Specifically, the outer side of the second storage cavity assembly 222 is connected to the first storage cavity assembly 221 through the first connecting plate 231 , and the position near the middle of the second storage cavity assembly 222 is connected to the first storage cavity assembly 221 through the second connecting plate 232 .

[0094] For example, in the connection method between the second storage cavity assembly 222 marked 5 and the second storage cavity assembly 6, the second storage cavity assembly 222 close to the side marked 11 is connected through the second connecting plate 232, and there is no space restriction on the outside of the second storage cavity assembly 222 away from the side marked 11, so the first connecting plate 231 is used to connect with the first storage cavity assembly 221.

[0095] The connection between the third storage cavity assembly 223 and the first storage cavity assembly 221 is achieved by using a second connecting plate 232 and a third connecting plate 233 . The third connecting plate 233 is located on the outside of the third storage cavity assembly 223 , and the second connecting plate 232 is located on the inside of the third storage cavity assembly 223 .

[0096] A second connecting plate 232 and a fourth connecting plate 234 are used between the third storage cavity assembly 223 and the second storage cavity unit. The second connecting plate 232 is located on the inner side of the third storage cavity assembly 223 , and the fourth connecting plate 234 is located on the outer side of the third storage cavity assembly 223 .

[0097] It should be noted that the inner side refers to the side closer to the middle of the fuel basket 2 , that is, closer to the position of the first storage cavity assembly 221 marked with number 11 .

[0098] Furthermore, the first connecting plate 231 is connected to the storage cavity assembly 22 by laser welding, the second connecting plate 232 is connected to the storage cavity assembly 22 by argon arc welding, and the third connecting plate 233 and the fourth connecting plate 234 are connected to the storage cavity assembly 22 by profile welding or argon arc welding; wherein, the fourth connecting plate 234 is flush with the outer end surface of the storage cavity assembly 22, and the first connecting plate 231, the second connecting plate 232 and the third connecting plate 233 are recessed in the plane of the outer end surface of the adjacent storage cavity assembly 22.

[0099] The first storage cavity component 221 is laser welded to ensure the welding quality and efficiency of the basic frame, and the integrity of the first storage cavity component 221 is also stronger after welding.

[0100] The second connecting plate 232 adopts short welding. Due to the small welding space, it is impossible to weld along the axial direction of the storage cavity assembly 22. Therefore, short welding at the end is adopted. At the same time, in order to ensure the welding quality of the first storage cavity assembly 221 and the second storage cavity assembly 222, argon arc welding is used to weld the position where there is operating space outside the first storage cavity assembly 221 and the second storage cavity unit.

[0101] A combination of short welding and argon arc welding is also used between the third storage cavity assembly 223 and the second storage cavity assembly 222 as well as between the third storage cavity assembly 223 and the first storage cavity assembly 221, which meets the requirements of overall welding while also ensuring welding quality.

[0102] Please refer to Figures 7 to 9The storage chamber assembly 22 includes a tube body 24, a neutron absorption plate 25 and a cladding 26; the neutron absorption plate 25 is arranged on the outer peripheral side of the tube body 24, the cladding 26 is covered on the outer side of the neutron absorption plate 25, and the cladding 26 is provided with anti-impact blocks 27 at both ends of the axial direction of the tube body 24, and an expansion gap 28 is left between the cladding 26 and the anti-impact block 27.

[0103] The neutron absorption plate 25 is fixed to the outer wall of the storage chamber assembly 22 by means of the cladding 26. The cladding 26 and the cylinder 1 are both made of 316 stainless steel. The cladding 26 and the outer wall of the storage chamber assembly 22 are connected by intermittent welding.

[0104] The anti-impact stopper 27 is used to limit the neutron absorption plate 25 in the axial direction to prevent the neutron absorption plate 25 from falling off during the transportation of the sealed container.

[0105] Specifically, the material of the neutron absorption plate 25 is aluminum-based boron carbide.

[0106] Please refer to Figures 10 to 13 A top cover 14 is also provided on the top of the cylinder 1, and a ventilation channel 141 and a drainage channel 142 are provided on the top cover 14. A sealing ring 143 is provided on the top of the ventilation channel 141 and the drainage channel 142; a shielding block 144 is provided on the ventilation channel 141 and the drainage channel 142 facing the cylinder 1.

[0107] A complete radioactive material containment boundary is formed between the cylinder 1 and the top cover 14, which can prevent the radioactive material in the cylinder 1 from escaping and polluting the external environment.

[0108] The ventilation channel 141 and the drainage channel 142 provide interfaces for connecting with a multifunctional stand to facilitate the execution of process operations such as water filling and exhaust, pressure testing, air filling and drainage, drying, and helium flushing.

[0109] Furthermore, the ventilation channel 141 and the drainage channel 142 penetrate the shielding block 144 , and the middle portions of the ventilation channel 141 and the drainage channel 142 are bent.

[0110] The shielding block 144 is used to compensate for the shielding capability of the top cover 14 at the openings of the ventilation channel 141 and the drainage channel 142 .

[0111] In one embodiment, a single-failure protection lug 145 is further provided on the top cover 14 .

[0112] The single fault protection lifting lug 145 is used to provide a lifting interface, and can carry the fuel basket 2 and the sealed container cylinder 1.

[0113] Furthermore, a drainage groove is provided at the bottom of the cylinder 1 .

[0114] The drain pipe on the top cover 14 can be directly inserted into the drain groove, thereby draining the residual water in the cylinder body 1 to the maximum extent.

[0115] In summary, the high burnup spent fuel storage and transportation dual-purpose sealed container provided by the present invention has the following advantages:

[0116] 1. Ensure the balance between storage and transportation.

[0117] The fuel basket 2 of the present invention adopts a 3-5-5-5-3 fuel basket 2 layout structure and improves the supporting structure, which makes the fuel basket 2 structure have better strength and rigidity, and can still maintain the arrangement array and spacing of the fuel even in extreme accidents such as falling and impact, thereby meeting the large-capacity requirements of storage and transportation while also meeting the safety of transportation.

[0118] 2. The sealed container has good corrosion resistance.

[0119] The cylinder 1 of the sealed container of the present invention is made of 316LN stainless steel, which has better corrosion resistance. After the spent fuel assembly is loaded, it can meet the requirements of intermediate storage for decades in the offshore smog corrosive environment and has good corrosion resistance.

[0120] 3. Good critical safety performance.

[0121] The fuel basket 2 is welded with a full-length connecting plate 23, so that the fuel basket 2 has good structural performance, and can still maintain the spacing between the storage chambers under accident transportation conditions such as a 9m drop during off-site transportation. Each storage chamber assembly 22 in the fuel basket 2 is surrounded by a neutron absorption plate 25. In this way, even if the sealed container is flooded, the spent fuel assembly therein can still be kept in a subcritical state, ensuring criticality safety under extreme accident conditions.

[0122] 4. Good natural circulation convection heat transfer performance.

[0123] Ventilation holes 21 are provided at the top and bottom of each storage cavity of the fuel basket 2, and a certain gap is left between the top and bottom of the fuel basket 2 and the cylinder 1, so that the sealed container can be guaranteed to have good natural circulation convection heat transfer performance, and the decay heat of high-burnup spent fuel can be effectively transferred to the outer wall of the cylinder 1, ensuring that the temperature of the spent fuel shell is below the limit.

[0124] 5. Good radiation safety characteristics.

[0125] During the process operation of the sealed container, the operator may approach from the top of the container. In order to reduce the radiation exposure of the operator to the high-burnup spent fuel, the top cover 14 of the sealed container is thickened. At the same time, a ventilation channel 141 and a drainage channel 142 are opened on the top cover 14, and a shielding block 144 with a bend is added at the ventilation channel 141 and the drainage channel 142, thereby ensuring the radiation safety of the operator.

[0126] 6. Good operating performance.

[0127] The key operations of the sealed container include the processes of filling the sealed container with water, exhausting, drying and filling with helium, and welding operations of the top cover 14 and the sealing ring 143.

[0128] The connecting welds of the top cover 14 or the sealing ring 143 are all complete annular welds, which facilitates the realization of automatic welding.

[0129] The processes of water filling, exhaust, drying and helium filling can be performed by connecting the sealed container to the multi-functional stand through the quick connectors of the ventilation channel 141 and the drainage channel 142. The design of the drainage pipe and the water collection tank in the sealed container also facilitates the drainage of residual water, thereby saving time for subsequent drying operations.

[0130] 7. Good retrievability.

[0131] When an operational failure occurs and needs to be corrected, the sealed container needs to be opened and the spent fuel needs to be retrieved.

[0132] The sealed container top cover 14 and the sealing ring 143 of the present invention adopt a complete annular weld, and a mounting interface for an automatic cutting machine is provided on the top of the top cover 14, thereby ensuring the retrievability of the spent fuel.

[0133] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "connect", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0134] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0135] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A sealed container for storage and transportation of high-burnup spent fuel, characterized in that: include: The inner wall of the cylinder is provided with a limited support assembly along its axial direction; The fuel basket is arranged inside the cylinder along the axial direction of the cylinder and cooperates with the limit support assembly; wherein, The outer peripheral side of the fuel basket and the inner wall of the cylinder are gap-matched and communicated with each other.

2. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 1 is characterized in that: The limit support assembly includes a plurality of angle limit supports and a plurality of line limit supports; The angular limit supports and the linear limit supports are both extended along the axial direction of the cylinder, and a plurality of the angular limit supports and a plurality of the linear limit supports are arranged at intervals.

3. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 1 is characterized in that: The top and the bottom of the fuel basket are respectively provided with ventilation holes, and the ventilation holes extend radially along the cylinder.

4. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 1, characterized in that: The fuel basket includes a plurality of spliced ​​storage cavity assemblies, and the storage cavity assemblies are welded via connecting plates.

5. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 4 is characterized in that: The storage cavity assembly is divided into a plurality of first storage cavity assemblies, a plurality of second storage cavity assemblies and a plurality of third storage cavity assemblies; A plurality of the first storage cavity components are arranged in a cross shape, a plurality of the second storage cavity components are arranged around the first storage cavity component, and a plurality of the third storage cavity components are arranged around the second storage cavity component; The fuel basket is formed by sequentially welding the first storage cavity assembly, the second storage cavity assembly, and the third storage cavity assembly.

6. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 5, characterized in that: The connecting plates include a plurality of first connecting plates, a plurality of second connecting plates, a plurality of third connecting plates and a plurality of fourth connecting plates; Adjacent first storage cavity components are connected via the first connecting plate, the first storage cavity component and the second storage cavity component are connected via the first connecting plate and the second connecting plate, the third storage cavity component and the first storage cavity component are connected via the second connecting plate and the third connecting plate, and the third storage cavity component and the second storage cavity component are connected via the second connecting plate and the fourth connecting plate; wherein, The first connecting plate is welded to the first storage cavity assembly along the axial direction of the storage cavity assembly, the second connecting plate is welded to the adjacent storage cavity assemblies at both ends of the adjacent storage cavity assemblies, and the third connecting plate and the fourth connecting plate are welded to the adjacent storage cavity assemblies along the axial direction of the storage cavity assembly.

7. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 6, characterized in that: The first connecting plate is connected to the storage chamber assembly by laser welding, the second connecting plate is connected to the storage chamber assembly by argon arc welding, and the third connecting plate and the fourth connecting plate are connected to the storage chamber assembly by profile welding or argon arc welding; wherein, The fourth connecting plate is flush with the outer end surface of the storage chamber assembly, and the first connecting plate, the second connecting plate and the third connecting plate are recessed in the plane of the adjacent outer end surface of the storage chamber assembly.

8. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 4, characterized in that: The storage chamber assembly includes a tube body, a neutron absorption plate and a cladding; The neutron absorption plate is arranged on the outer peripheral side of the tube body, the cladding cover is arranged on the outer side of the neutron absorption plate, and the cladding is provided with anti-impact blocks at both ends along the axial direction of the tube body, and an expansion gap is left between the cladding and the anti-impact blocks.

9. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 8, characterized in that: The cylinder and the cladding are made of 316 stainless steel; The material of the neutron absorption plate is aluminum-based boron carbide.

10. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 1, characterized in that: The top of the cylinder is also provided with a top cover, on which a ventilation channel and a drainage channel are provided, and sealing rings are provided on the tops of the ventilation channel and the drainage channel; The ventilation channel and the drainage channel are provided with shielding blocks facing the cylinder.

11. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 10, characterized in that: The ventilation channel and the drainage channel are both ventilated and drained through quick joints, and the top cover is used to seal the ventilation channel and the drainage channel after ventilation and drainage.

12. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 11, characterized in that: The ventilation channel and the drainage channel are arranged through the shielding block, and the middle parts of the ventilation channel and the drainage channel are bent.

13. The high burnup spent fuel storage and transportation dual-purpose sealed container according to claim 10, characterized in that: The top cover is also provided with a single fault protection lifting lug.

14. The sealed container for storage and transportation of high burnup spent fuel according to any one of claims 1 to 13, characterized in that: A drainage groove is provided at the bottom of the cylinder.

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