A vertical non-destructive sample preserving spent fuel storage tank and storage system and method of operation

Abstract

The application provides a vertical non-destructive sample-remaining spent fuel storage tank and a storage system and an operating method. An independent through isolation bin is constructed in the inside of a welded sealing container body. The bottom of the through isolation bin is welded and sealed with a bottom cover, and the top is fixed to an inner top cover. The inside space is completely isolated from the radioactive sealing environment in the container, but is open to the outside atmosphere. A sampling cylinder containing a test sample is hung and placed in the isolation bin through the opening of the through isolation bin for long-term sample remaining, and is radiologically shielded by a detachable plugging assembly. When aging analysis sampling is performed, the plugging assembly only needs to be removed, and the sampling cylinder can be taken out. The whole process does not need to be taken back or cut the container, realizes true non-destructive sampling, and does not occupy the effective loading space of the spent fuel.

Description

Technical Field

[0001] This invention relates to the field of spent fuel storage technology in nuclear power plants, and in particular to a vertical non-destructive sampling tank for spent fuel, a storage system, and an operating method. Background Technology

[0002] Due to the limited storage capacity of water pools, dry storage technology is widely used internationally as an intermediate storage solution for spent fuel assemblies unloaded from nuclear power plants. Existing dry storage containers for spent fuel generally employ a welded, sealed structure design. Internal fuel baskets are used to store spent fuel assemblies, and after loading, the entire assembly is welded and sealed inside the container for long-term storage. An external concrete silo provides structural protection and radiation shielding. According to nuclear safety regulations, aging analysis and periodic safety assessments of key components and materials of the storage container must be conducted every ten years. However, the existing welded, sealed structure completely encloses the materials of critical functional components inside the container. If sampling and analysis are required, the container must be destructively cut open for retrieval, resulting in complex operations, high safety risks, and the non-reusability of the container. If monitoring samples are only placed on the outer surface of the container, the external ambient temperature and radiation dose levels are far lower than the actual internal operating conditions, making it difficult to accurately reflect the aging effects of the materials and providing an inaccurate and reliable basis for aging analysis and life prediction. Summary of the Invention

[0003] This invention provides a vertical non-destructive sampling spent fuel storage tank and storage system and operation method to solve the technical problems of spent fuel storage containers where internal material samples cannot be safely and conveniently removed due to the welded sealing structure, where sampling analysis requires damage to the container body structure, and where external monitoring sample data cannot accurately reflect the material aging effect under the internal high temperature and high radiation environment.

[0004] The vertical non-destructive sampling spent fuel storage tank provided by the present invention includes: The container body is a vertical cylindrical structure with a sealed enclosing cavity inside for accommodating spent fuel assemblies, and an opening is provided at the top of the container body. A through-isolation chamber is vertically disposed inside the container body along the axial direction of the container body, with its two ends sealed to the bottom and top of the container body, respectively. A sample retention chamber is formed inside the through-isolation chamber, which is isolated from the sealed enclosure and communicates with the external atmospheric environment only through the opening. A sampling tube, housed within the sample retention cavity, is used to store test samples; A sealing assembly is installed at the opening to seal the sample retention chamber.

[0005] In an optional embodiment of the present invention, the container body includes a shell, a bottom cover, a top inner cover plate, and a top outer cover plate, and the sealed enclosure cavity is formed by the shell, the bottom cover, the top inner cover plate, and the top outer cover plate. The bottom end of the through-isolation chamber is sealed and welded to the bottom cover, and the top end passes through the inner top cover plate and the outer top cover plate in sequence and is sealed and welded to them respectively.

[0006] In an optional embodiment of the present invention, the through-hole isolation chamber includes a main chamber cylinder, which is a hollow cylindrical structure with a thick upper wall and a thin lower wall, and its bottom inner and outer sides are welded to the bottom cover to form a double seal.

[0007] In one optional embodiment of the present invention, the top inner wall of the main chamber is provided with a tapered surface with a narrowing diameter for supporting and positioning the sealing assembly.

[0008] In an optional embodiment of the present invention, a threaded sealing surface is provided on the inner top side of the main chamber above the conical surface, for use in conjunction with the sealing assembly to achieve threaded sealing.

[0009] In an optional embodiment of the present invention, the through-hole isolation chamber further includes a protective collar, which is nested around the top outer periphery of the main chamber cylinder and welded and fixed to the upper annular region of the main chamber cylinder.

[0010] In an optional embodiment of the present invention, the top inner cover plate is a metal cover plate with a first through hole in the center. The first through hole is nested around the outer periphery of the through isolation chamber. The outer edge of the top inner cover plate is sealed to the shell by a first circumferential weld. The edge of the first through hole is sealed to the through isolation chamber by a second circumferential weld.

[0011] In an optional embodiment of the present invention, the top outer cover plate is a metal cover plate with a second through hole in the center. The second through hole is nested around the outer periphery of the through isolation chamber. The edge of the second through hole is sealed to the through isolation chamber by a third circumferential weld. The outer edge of the top outer cover plate is sealed to the shell by a fourth circumferential weld.

[0012] In an optional embodiment of the present invention, the top inner cover plate is further provided with an inflation hole, a drainage hole, and quick connectors and drainage pipes that are matched with the inflation hole and drainage hole, for realizing the inflation and drainage, vacuum drying and helium filling operations of the sealed cavity.

[0013] In an optional embodiment of the present invention, the sampling cylinder includes: A sampling housing is disposed within the sample retention chamber; A conical plug is installed at one end of the sampling housing; A sample retention unit is housed inside the sampling housing.

[0014] In an optional embodiment of the present invention, the sample retention unit includes: A support rod is installed inside the sampling housing; A lifting handle is provided at the top of the support rod; A base is located at the bottom end of the supporting rod; The storage bag is fixed to the support rod. A stop plate is fixed to the upper part of the support rod and located at the lower end of the conical plug. The diameter of the stop plate is larger than the diameter of the central through hole of the conical plug, so that when the lifting handle is lifted, the conical plug is supported by the stop plate, thereby removing the entire sampling cylinder from the sample retention chamber.

[0015] In an optional embodiment of the present invention, the storage bags are arranged in layers along the axial direction of the supporting rod, and each layer has a plurality of storage bags evenly distributed circumferentially. Each storage bag is a hollow bag with an opening at the top and sealed at the bottom and around the perimeter, used to store test samples.

[0016] In an optional embodiment of the present invention, the storage bag is made of a low-activation material.

[0017] In an optional embodiment of the present invention, the sealing assembly includes a sealing plug and a shielding plug. The shielding plug is freely located inside the top of the through-hole isolation chamber to provide radiation shielding. The sealing plug is installed above the shielding plug and seals against the inner wall of the top of the through-hole isolation chamber to provide structural protection and top sealing.

[0018] In an optional embodiment of the present invention, the shielding plug is a columnar structure with a gradually decreasing diameter, and its outer wall matches the conical surface that penetrates the inner wall of the isolation chamber; The top of the shielding plug is provided with a first screwing operation part and a first positioning hole, which are used to cooperate with external operating tools to achieve remote picking and placing.

[0019] In an optional embodiment of the present invention, the sealing plug is a cylindrical threaded sealing structure with external threads on its outer periphery for engaging with the threaded sealing surface that penetrates the inner wall of the top of the isolation chamber. The top of the sealing plug is provided with a second screwing operation part and a second positioning hole, which are used to cooperate with external operating tools to achieve remote disassembly and assembly.

[0020] In an optional embodiment of the present invention, a fuel basket is provided inside the sealed containment cavity. The fuel basket consists of multiple fuel storage units, each of which is used to store a set of spent fuel assemblies. The through-barrier compartment occupies the position of one fuel storage unit in the fuel basket adjacent to the axial region.

[0021] The present invention also proposes a spent fuel storage system, comprising a spent fuel storage container as described in any of the above embodiments, and a vertical concrete silo for housing the spent fuel storage container.

[0022] This invention also proposes an operation method for a vertical non-destructive sampling spent fuel storage tank, comprising: After the container body and the through-isolation chamber are welded together, the sampling tube containing the test sample is hoisted into the sample retention chamber through the opening of the through-isolation chamber. Install the shielding plug and the sealing plug in sequence to seal the sample retention chamber; After the spent fuel assembly is loaded, the inner and outer top cover plates of the container body are welded and sealed. When it is necessary to remove the test sample, first remove the sealing plug and the shielding plug in sequence, and then lift the sampling tube out of the sample retention cavity through the opening.

[0023] The beneficial effects of this invention are as follows: The vertical non-destructive sampling spent fuel storage tank, storage system, and operation method proposed in this invention, by constructing a through-isolation chamber on the sealed boundary of the container and placing the sampling tube outside the sealed boundary, enables sampling from the top without cutting the container or damaging the sealing structure, significantly improving operational safety and economy; by arranging the through-isolation chamber at the fuel unit position near the axial region of the fuel basket, the monitoring sample in the sampling tube is subjected to the real aging environment with the highest temperature and strongest radiation dose, ensuring the representativeness and accuracy of the aging analysis data; by adopting a double-layer sealing structure of shielding plug and sealing plug, which respectively undertake the functions of radiation shielding and structural protection, the sealing safety of the sampling chamber is ensured during long-term storage; through the layered circumferential arrangement of the sampling unit, precise staged monitoring of different positions of the axial active section of spent fuel is achieved, providing systematic data support for conducting periodic safety assessments. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0025] In the attached diagram: Figure 1 This is a schematic diagram of a non-destructive sampling and storage system for spent fuel provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a sampling operation provided in one embodiment of the present invention; Figure 3 This is a schematic diagram (1 / 4 section) of the structure of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 4 This is a top view of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention (with the cover plate removed). Figure 5 This is a schematic diagram of the structure of the cylinder and the through-isolation chamber of the vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 6 This is a schematic diagram of the through-isolation compartment of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 7 This is a schematic diagram (1 / 4 section) of the sealing structure of the through-isolation compartment of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 8 This is a cross-sectional view of the top inner cover plate of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 9 This is a top view of the inner top cover of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 10 This is a cross-sectional view of the top outer cover plate of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 11 This is a schematic diagram (1 / 4 section) of the sealing structure of the container body and the through-isolation chamber of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 12 This is a schematic diagram of the sampling cylinder retrieval operation structure provided in one embodiment of the present invention (section 1 / 4). Figure 13 This is a schematic diagram of the shielding plug of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 14 This is a schematic diagram of the sealing plug of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 15 This is a schematic diagram (1 / 4 section) of the sampling cylinder of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 16 This is a schematic diagram of the sampling unit of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 17 This is a schematic diagram illustrating the function of the conical plug and stop plate in a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention. Figure 18 This is a schematic diagram of the sample collection bag unit of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 19 This is a schematic diagram illustrating the loading and retrieval of the sampling unit of a vertical non-destructive sampling spent fuel storage tank according to an embodiment of the present invention; Figure 20 This is a schematic diagram of the structure of the fuel basket of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 21 This is a schematic diagram of the square tube structure of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 22 This is a structural grid plate of a vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention; Figure 23 This is a schematic diagram of the structure of the heat transfer grid plate of the vertical non-destructive sampling spent fuel storage tank provided in one embodiment of the present invention.

[0026] The attached figures are labeled as follows: 100. Container body; 200. Penetrating isolation chamber; 300. Sampling tube; 400. Sealing assembly; 500. Fuel basket; 600. Vertical concrete silo; 700. Concrete cover plate; 110. Shell; 120. Bottom cover; 130. Inner top cover plate; 140. Outer top cover plate; 131. First through hole; 132. Welded surface of the first isolation chamber; 133. Welded surface of the first cylinder; 134. Inflation port; 135. Drainage port; 136. Quick connector for inflation port; 137. Quick connector for drainage port; 138. Drain pipe; 141. Second through hole; 142. Welded surface of the second isolation chamber; 143. Welded surface of the second cylinder; 210. Main chamber cylinder; 220. Protective collar; 230. Inner cover welding surface; 240. Outer cover welding surface; 250. Tapered surface; 260. Threaded sealing surface; 310. Sampling housing; 320. Base plate; 330. Support; 340. Conical plug; 350. Sample retention unit; 341. Cone; 342. Third through hole; 343. Plug sealing surface; 351. Lifting handle; 352. Support rod; 353. Base; 354. Storage bag; 355. Stop plate; 410. Shielding plug; 420. Sealing plug; 411. Filling section; 412. Fitting section; 413. First positioning hole; 414. First screwing groove; 415. First stop plate; 421. External thread surface; 422. Second positioning hole; 423. Second screwing groove; 424. Second stop plate; 510. Square tube; 520. Structural grid plate; 530. Heat transfer grid plate. Detailed Implementation

[0027] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0028] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0029] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0030] Spent fuel assemblies discharged from nuclear power plants are typically temporarily stored in water pools. However, due to the limited storage capacity of these pools and insufficient reprocessing capabilities, dry storage technology is widely adopted internationally as an intermediate storage solution. Taking vertical dry storage technology as an example, its core equipment, the spent fuel storage container, employs a welded, sealed structure. Internally, fuel baskets are installed, with each basket holding one set of spent fuel assemblies. Neutron absorber plates surround the fuel baskets, providing critical safety control functions throughout their lifespan. After the spent fuel assemblies are loaded into the fuel baskets, they are welded and sealed inside the storage container for long-term storage. A concrete silo is located outside the spent fuel storage container, providing structural protection and radiation shielding. According to nuclear safety regulatory requirements, aging analysis and periodic safety assessments must be conducted every ten years on key components and materials of the spent fuel storage container.

[0031] However, existing technologies face significant challenges in conducting aging analysis. First, current spent fuel storage containers all employ a welded, sealed design, with spent fuel, fuel baskets, and key functional components all welded and sealed inside. Sampling requires cutting the container, which, under high temperature and irradiation conditions, presents complex operational challenges, high safety risks, and the risk of structural damage that renders the container unusable. Second, even considering placing monitoring samples on the outer surface of the container, the external ambient temperature and radiation dose levels are far lower than the actual levels inside the container, making it difficult to accurately reflect the long-term effects of high temperature and irradiation on the aging of core functional components. This fails to provide accurate and reliable data for aging analysis and lifespan prediction. Therefore, there is an urgent need for a vertical, non-destructive sampling spent fuel storage tank that offers accurate sampling data, convenient operation and maintenance, and is safe and economical.

[0032] Please see Figures 1 to 23This invention proposes a vertical non-destructive sampling spent fuel storage tank. The storage container mainly includes a container body 100, a through-isolation chamber 200, a sampling cylinder 300, a sealing assembly 400, and a fuel basket 500. The container body 100 is a vertical cylindrical structure with a sealed containment cavity inside for accommodating spent fuel assemblies. The fuel basket 500 for loading and securing the spent fuel assemblies is disposed within the sealed containment cavity. An opening is provided at the top of the container body 100. The container body 100 can be made of stainless steel or other metal materials suitable for containing radioactive materials, possessing sufficient structural strength and radiation shielding capability. The through-isolation chamber 200 is vertically disposed inside the container body 100 along its axial direction, with its two ends sealed to the bottom and top of the container body 100, respectively. A sampling cavity is formed inside the through-isolation chamber 200, which is isolated from the sealed containment cavity and communicates with the external atmosphere only through the opening. The sampling cylinder 300 is housed within the sampling cavity and is used to store test samples. The sampling tube 300 can be removed or inserted entirely from the sample retention chamber without any cutting or welding of the container body 100 or the through-isolation chamber 200 during removal and insertion. A sealing assembly 400 is installed at the opening to seal the sample retention chamber. During routine storage, the sealing assembly 400 seals and protects the sample retention chamber while reducing the radiation dose level from the top area to the surrounding environment. Because the sampling chamber is physically located outside the sealed enclosure boundary of the entire spent fuel storage container and inside the through-isolation chamber 200, it is completely isolated from the spent fuel assemblies and radioactive atmosphere. During periodic sampling and safety analysis and evaluation, it is only necessary to remove the concrete cover plate 700 of the vertical concrete silo 600 and disassemble the sealing assembly 400 from the top of the container body 100. The sampling tube 300 can then be hoisted out of the sampling chamber, and the various key material samples pre-installed and fixed inside the sampling tube 300 can be taken out for testing. The entire process does not require any damage to the sealed enclosure, achieving truly non-destructive sampling and solving the technical problem of difficult sampling of existing welded sealed containers.

[0033] Please see Figures 1 to 5In an optional embodiment of the present invention, the container body 100 is a vertical cylindrical metal cylinder structure, comprising a shell 110, a bottom cover 120, a top inner cover plate 130, and a top outer cover plate 140. The shell 110, bottom cover 120, top inner cover plate 130, and top outer cover plate 140 are all made of metal, collectively defining the aforementioned sealed containment cavity, constituting the containment boundary of the entire spent fuel storage container. The sealed containment cavity houses spent fuel assemblies and a matching fuel basket 500. The opening of the container body 100 is located at its top, specifically penetrating the central area of ​​the top inner cover plate 130 and the top outer cover plate 140, for engagement with the top end of the penetration isolation chamber 200. The bottom end of the penetration isolation chamber 200 is sealed and welded to the bottom cover 120, and the top end sequentially penetrates the top inner cover plate 130 and the top outer cover plate 140 and is sealed and welded to both respectively. During the factory manufacturing stage, the annular metal shell 110 and the bottom cover 120 are first welded together to form the basic structure of the main cylinder. Then, the inner and outer sides of the bottom of the cylinder that penetrates the isolation chamber 200 are welded to the upper axis periphery of the bottom cover 120 to form the sealed containment boundary of the bottom area of ​​the container and the core structure of the non-destructive sampling spent fuel storage container cylinder. Finally, the fuel basket 500 is hoisted into the spent fuel storage container cylinder.

[0034] Please see Figures 1 to 7 In an optional embodiment of the present invention, the through-isolation chamber 200 is disposed in the axial region of the container body 100 to achieve sample monitoring and rapid retrieval from the representative high-temperature, high-irradiation area in the central region. The through-isolation chamber 200 is welded and sealed to the bottom of the container body 100, and completely penetrates and is welded in layers to the top cover plate. Specifically, the through-isolation chamber 200 includes a main chamber cylinder 210 and a protective collar 220, and forms an inner cover welding surface 230 and an outer cover welding surface 240. The main chamber cylinder 210 is a hollow cylindrical structure with a thick upper wall and a thin lower wall, for example, it can be a cylindrical cylinder. The inner and outer sides of the bottom end of the main chamber cylinder 210 are completely welded to the bottom cover 120 to achieve double redundant sealing. The internal space of the main chamber cylinder 210 constitutes the sample retention chamber. It should be noted that the shape of the main chamber 210 is not limited. In other embodiments, the main chamber 210 may also adopt a hollow cylindrical structure with a polygonal body or other cross-sectional shape, as long as it can form an independent sample retention cavity isolated from the sealed containment cavity.

[0035] Please see Figures 1 to 7In an optional embodiment of the present invention, the top inner wall of the main chamber 210 is provided with a tapered surface 250 with a tapered diameter that tapers. This tapered surface 250 is used to support and position the sealing assembly 400. By hoisting the sealing assembly 400 to the tapered surface 250, the tapered fitting surface of its outer wall matches the tapered surface 250, achieving automatic centering, positioning, and fixation of the sealing assembly 400. A threaded sealing surface 260 is also provided on the top inner side of the main chamber 210 above the tapered surface 250. This threaded sealing surface 260 is used to cooperate with the sealing assembly 400 to achieve a threaded seal. After the sealing assembly 400 is installed, the threaded sealing surface 260 provides structural protection for the sampling cylinder 300.

[0036] Please see Figures 1 to 7 In an optional embodiment of the present invention, the protective collar 220 is nested around the top outer periphery of the main compartment 210 and is welded and fixed to the entire upper annular area of ​​the main compartment 210. The protective collar 220 serves two purposes: firstly, it prevents interference between the welding head structure and the top cover of the spent fuel storage container and the through-isolator 200 during welding operations; secondly, it prevents potential welding deformation of the isolation compartment, ensuring the welding quality and sealing reliability of the top area.

[0037] Please see Figure 4 In an optional embodiment of the present invention, the through-isolator 200 occupies the position of one fuel storage unit in the fuel basket 500 adjacent to the central axis. Based on analysis of existing spent fuel loading schemes, the central area is the region with the highest temperature and strongest radiation. Therefore, the through-isolator 200 is arranged as one of the fuel units around the central axis to ensure the representativeness and accuracy of the aging effect detection data of the sampled specimens (including neutron absorber material specimens, metal material specimens, etc.). Simultaneously, this arrangement does not require any structural adjustments to the existing fuel basket 500 design, exhibiting good compatibility and economy.

[0038] Please see Figures 1 to 9In an optional embodiment of the present invention, the top inner cover plate 130 is a thick cylindrical metal cover plate with a first through hole 131 at its center, and has a first isolation chamber welding surface 132 and a first cylindrical body welding surface 133. The first through hole 131 is matched with the through isolation chamber 200. When the spent fuel assembly is loaded, the first through hole 131 of the top inner cover plate 130 is nested into the outer periphery of the through isolation chamber 200 and installed in place. The outer edge of the top inner cover plate 130 is provided with the first cylindrical body welding surface 133, which is welded and sealed with the storage container shell 110 by a first circumferential weld. The first isolation chamber welding surface 132 is formed at the edge of the first through hole 131, which matches the corresponding welding surface of the through isolation chamber 200. By applying annular welding in this area, a second circumferential weld is formed, achieving a seal between the through hole area of ​​the top inner cover plate 130 and the through isolation chamber 200. Through the above two welds, a sealed enclosure between the top inner cover plate 130, the through isolation chamber 200, and the shell 110 is achieved.

[0039] Please see Figures 1 to 9 In an optional embodiment of the present invention, the top inner cover plate 130 is further provided with an inflation port 134, a drainage port 135, and quick-connect fittings 136 and 137 for the inflation port 134 and drainage port 135, and a drainage pipe 138. The drainage pipe 138 extends from the inside of the container to the bottom region. The function of these process interfaces is to enable the inflation and drainage, vacuum drying, and helium filling operations of the spent fuel storage container, ensuring that the interior of the container reaches the required inert gas protection environment before final welding and sealing.

[0040] Please see Figures 1 to 10 In one optional embodiment, the top outer cover plate 140 is a circular metal cover plate with a second through hole 141 at its center, and has a second isolation chamber welding surface 142 and a second cylinder welding surface 143. After the welding of the top inner cover plate 130 is completed, the top outer cover plate 140 is installed on top of the top inner cover plate 130. The second through hole 141 is nested around the outer periphery of the through isolation chamber 200, and the second isolation chamber welding surface 142 is provided at the edge of the second through hole 141, which matches the corresponding welding surface of the through isolation chamber 200 to form a welding bevel. By applying an annular area weld in this area, a third annular weld is formed, thereby achieving a seal between the through hole area of ​​the top outer cover plate 140 and the through isolation chamber 200. The outer edge of the top outer cover plate 140 is provided with a second cylinder welding surface 143, which is sealed to the storage container shell 110 by a fourth annular weld. The two welds mentioned above achieve redundant sealing between the top outer cover plate 140 and the through-isolation chamber 200 and shell 110, which together with the two welds of the top inner cover plate 130 form a double-layer redundant sealing boundary in the top area.

[0041] Please see Figures 1 to 11It should be noted that the container body 100 undertakes important functions such as sealing and containing spent fuel, criticality control, radiation shielding, and thermal safety. The sealing of the container body 100 is achieved through multiple key welds. Among them, the sealing and containing boundary of the bottom region includes: a circumferential weld between the shell 110 and the bottom cover 120, forming an outer bottom seal; and welds between the inner and outer sides of the bottom of the cylinder penetrating the isolation chamber 200 and the bottom cover 120, forming a double redundant seal on the inner bottom side. The sealing and containing boundary of the top region consists of four welds: the inner top cover plate 130 and the penetrating isolation chamber 200, the inner top cover plate 130 and the shell 110, the outer top cover plate 140 and the penetrating isolation chamber 200, and the outer top cover plate 140 and the shell 110. Specifically, the first through hole 131 of the top inner cover plate 130 matches the outer cover welding surface 240 of the protective sleeve 220, and a V-groove weld is provided between them; the second through hole 141 of the top outer cover plate 140 matches the top inner cover welding surface 230 of the main silo 210, and a V-groove weld is provided between them. These welds together constitute a complete sealed boundary for the periphery of the shaft, penetrating the hollow cylindrical structure and the spent fuel storage container, ensuring that radioactive materials are firmly contained within the space defined by the welds, while the sample retention chamber remains outside these sealed boundaries.

[0042] Please see Figures 1 to 12 In one specific embodiment, after fuel loading is completed at the nuclear power plant site, welding and sealing of four areas are required to establish a double-layer redundant sealed containment boundary for the top area of ​​the spent fuel storage container. Specifically, firstly, the top inner cover plate 130 is installed, and the first zone weld (i.e., the first circumferential weld) between the first through hole 131 and the outer cover welding surface 240 of the through-isolation chamber 200 is completed; then, the second zone circumferential weld (i.e., the second circumferential weld) between the inner cover plate and the cylinder is completed; then, the top outer cover plate 140 is installed, and the third zone weld (i.e., the third circumferential weld) between the through hole of the outer cover plate and the inner cover welding surface 230 of the through-isolation chamber 200 is completed; finally, the fourth zone circumferential weld (i.e., the fourth circumferential weld) between the outer cover plate and the cylinder is completed. Combining the two bottom welds during the manufacturing stage (the fifth ring weld between the shell 110 and the bottom cover 120, and the sixth ring weld between the inner and outer sides of the bottom of the penetrating isolation chamber 200 and the bottom cover 120), the entire container body 100 forms a complete sealed enclosure boundary through six welded areas (four on top and two on the bottom). Based on this sealed enclosure boundary and the hollow penetrating isolation chamber in the axial center, after the spent fuel loading and sealing are completed, the sampling tube 300 is hoisted and installed inside the penetrating isolation chamber 200, and sealed using the sealing assembly 400. During the installation and retrieval of the sampling tube 300, the spent fuel storage container remains in a safe, sealed enclosure state without any leakage of radioactive materials, achieving non-destructive sampling and preservation of the core area of ​​the spent fuel storage container's axial center.

[0043] Please see Figures 1 to 14 In an optional embodiment of the present invention, the sealing assembly 400 includes a shielding plug 410 and a sealing plug 420, which are arranged in a double-layered manner. The shielding plug 410 is freely located inside the top of the penetrating isolation chamber 200, at the bottom; the sealing plug 420 is installed above the shielding plug 410 and seals against the inner wall of the top of the penetrating isolation chamber 200. The shielding plug 410 provides radiation shielding for the top cover area, and the sealing plug 420 provides structural protection for the sampling cylinder 300. When periodically sampling for aging analysis, the sealing plug 420 and the shielding plug 410 are first removed, and then the sampling cylinder 300 installed inside the penetrating isolation chamber 200 is taken out. The material sample in the sampling cylinder 300 can then be taken out for testing, realizing non-destructive sampling and aging analysis of the structure of the spent fuel storage container body 100.

[0044] Please see Figures 1 to 14 In an optional embodiment of the present invention, the shielding plug 410 is a cylindrical structural unit with a gradually decreasing diameter and is made of metals such as steel and lead or metal composite base shielding materials, serving as the radiation shielding function for the entire top of the isolation penetration chamber. The outer wall of the shielding plug 410 is provided with a gradually decreasing fitting surface that matches the conical surface 250 of the inner wall of the penetration isolation chamber 200. By hoisting the shielding plug 410 to the constricting conical surface 250 at the top of the isolation chamber, the shielding plug 410 is automatically centered, positioned, and fixed. The shielding plug 410 includes a filling section 411 at the bottom and a fitting section 412 at the top, and the top of the shielding plug 410 is provided with a first screwing operation part and a first positioning hole 413 for use with external operating tools to achieve remote placement and removal. Specifically, the first screwing operation part may include, for example, an annular first screwing groove 414 and a first stop plate 415 structure evenly distributed at the top. In specific operation, firstly, the long-handled tool is inserted into the first positioning hole 413 to achieve positioning and centering. Then, the gripper is inserted into the first screwing groove 414. The long-handled tool is then rotated so that the gripper enters the bottom of the first stop plate 415. Then, the long-handled tool is lifted, and the entire shielding plug 410 is removed from the through isolation chamber 200 by the action of the stop plate.

[0045] Please see Figures 1 to 14In an optional embodiment of the present invention, the sealing plug 420 is a thin-walled, lightweight cylindrical threaded sealing structure unit. The outer periphery of the sealing plug 420 is provided with an external threaded surface 421, which mates with the threaded sealing surface 260 penetrating the inner wall of the top of the isolation chamber 200. The top of the sealing plug 420 is provided with a second screwing operation part and a second positioning hole 422, which are used to cooperate with external operating tools to achieve remote assembly and disassembly. The second screwing operation part can also be an annular second screwing groove 423 and a second stop plate 424 evenly distributed on the top. In specific operation, firstly, a screwing long rod tool is inserted into the second positioning hole 422 for positioning and centering. Then, a gripper is inserted into the second screwing groove 423, and the long rod tool is rotated so that the gripper enters the bottom of the second stop plate 424. Then, the long rod tool is continuously screwed until the external threaded surface 421 of the sealing plug 420 corresponds one-to-one with the threaded sealing surface 260 penetrating the top of the isolation chamber 200, thereby achieving structural protection of the sampling cylinder 300 and top sealing of the sample retention chamber. When it is necessary to retrieve the sampling cylinder 300, the reverse operation can be performed.

[0046] It should be noted that the specific structural form of the sealing component 400 is not limited. In other embodiments, the shielding plug 410 and the sealing plug 420 may also adopt other forms of remote operation interfaces, or the two may be integrated into a sealing component that has both shielding and sealing functions, as long as the sample retention cavity can be detachably sealed from the top.

[0047] Please see Figures 1 to 19 In an optional embodiment of the present invention, the sampling cylinder 300 performs the function of sampling and retention. It is a long and hollow cylindrical metal unit. The sampling cylinder 300 is located outside the sealed enclosure boundary of the entire spent fuel storage container and inside the isolation chamber 200.

[0048] For details, please refer to Figures 15 to 19The sampling cylinder 300 includes a sampling housing 310, a base plate 320, a support 330, a conical plug 340, and a sample retention unit 350. The sampling housing 310, base plate 320, and support 330 constitute the main structure of the sampling cylinder 300. The sample retention unit 350 is housed inside the sampling housing 310. The conical plug 340 is a conical structural unit with a through vertical hole at its center, installed at the top of the sampling housing 310, and penetrated by a long rod in the middle of the sample retention unit 350. The conical plug 340 and the sampling housing 310 are sealed by screwing. During the sample retention stage, various sample pieces are first fixed in layers on the sample retention unit 350, then the sample retention unit 350 is placed inside the sampling cylinder 300, and then the conical plug 340 and the sampling housing 310 are sealed by screwing, and finally the sampling cylinder 300 is placed inside the through isolation chamber 200. During the sampling stage, the sampling cylinder 300 is first removed from the through-isolation chamber 200, and then the conical plug 340 is loosened and removed from the sampling housing 310 by screwing it in. Next, the retention unit 350 is removed from the sampling cylinder 300, and finally, the various sample pieces that are fixed in layers on the retention unit 350 are extracted for testing and aging analysis.

[0049] Please see Figures 15 to 19 In an optional embodiment of the present invention, the sample retention unit 350 includes a lifting handle 351, a supporting rod 352, a base 353, a storage bag 354, and a stop plate 355. The supporting rod 352 is disposed inside the sampling housing 310, with a spherical crown-shaped lifting handle 351 at its upper end and a disc-shaped base 353 at its lower end. The storage bag 354 is fixed to the supporting rod 352 and is used to store test samples. The conical plug 340 includes a cone 341, a third through hole 342, and a plug sealing surface 343. The stop plate 355 is a disc welded and fixed to the upper part of the support rod 352. It is located at the lower end of the through hole of the conical plug 340, and its diameter is larger than the diameter of the central through hole of the conical plug 340. The stop plate 355 serves as a stop force-bearing unit to lift the entire sampling cylinder 300. The conical plug 340 and the sampling housing 310 are connected by screw threads to form a structural whole. When the sampling cylinder 300 is lifted by gripping the spherical lifting handle 351 and the support rod 352, the entire sampling cylinder 300 is taken out from the through isolation chamber 200 by the lifting action of the stop plate 355 on the entire conical plug 340.

[0050] Please see Figures 15 to 19In one specific embodiment, the storage bags 354 are arranged in layers along the axial direction of the supporting rod 352, for example, in six layers, and fixed around the supporting rod 352. Each layer has multiple storage bags 354 evenly distributed circumferentially, for example, six storage bags 354 per layer. Each storage bag 354 is a hollow cuboid pocket with an open top and sealed bottom and perimeter, used to store test samples. The storage bags 354 are made of low-activation materials, such as low-activation steel, tungsten alloys, and silicon carbide. The central cavity inside the storage bag 354 is a cuboid chamber used to store neutron absorber material samples, stainless steel, or other material samples that characterize the aging effects of key components of the cylinder. Each layer of storage bags 354 is distributed in the active section region corresponding to the spent fuel assembly to ensure accurate analysis and evaluation of the aging effects of spent fuel temperature and irradiation on the samples.

[0051] Please see Figures 15 to 19 When loading the sample retention unit 350, thin-walled cuboid material samples of specified structural dimensions are first pre-processed. These samples are then inserted one by one into the cavity of the storage bag 354 along the direction of the support rod 352 and marked, until each layer of storage bag 354 is filled from bottom to top. When it is necessary to retrieve the sample from the sample retention unit 350 every ten years for aging analysis, the conical plug 340 is first unscrewed from the sampling cylinder 300, and then the sample retention unit 350 is directly removed from the cylinder. Then, a single sample from each layer is taken out for analysis. In a specific embodiment, based on the sixty-year lifespan design of the spent fuel storage container, samples are retrieved every ten years. Correspondingly, every ten years, a complete row of samples can be retrieved from six layers from top to bottom for analysis. This allows for a detailed assessment of the aging effects of the temperature field and radiation dose field at different locations in the axial active section region of the spent fuel on the samples, providing accurate data support for conducting periodic safety assessments.

[0052] It should be noted that the number of sample retention layers and the number of storage bags 354 are not limited. In other embodiments, actual users can also set other numbers of sample retention layers and the number of storage bags 354 per layer according to the needs of aging analysis. The material of the storage bags 354 can also be selected from other low-activation materials as needed. The method of fixing the sample is not limited to the storage bags 354; other fixing methods such as clamping plates and elastic buckles can also be used.

[0053] Please see Figures 1 to 23In an optional embodiment of the present invention, a fuel basket 500 for loading and fixing spent fuel assemblies is provided within a sealed enclosure. The fuel basket 500 consists of multiple fuel storage units, each used to store a set of spent fuel assemblies. The fuel basket 500 includes three parts: a square tube 510, a structural grid plate 520, and a heat transfer grid plate 530. The square tube 510 is an independently machined, hollow, thin-walled, rectangular stainless steel structural unit with a square cross-section, and neutron absorber material is welded and coated on each side of the square tube 510. The structural grid plate 520 is a stainless steel structural frame unit with through holes matching the shape of the square tube 510, which provides structural protection for the entire fuel basket 500 unit. The heat transfer grid plate 530 is an aluminum heat transfer structural unit with through holes matching the shape of the square tube 510, which conducts heat for the decay heat of spent fuel.

[0054] Please see Figures 1 to 23 During on-site assembly, the initial grid plates are first positioned, stacked, and fixed. Then, square tubes 510 are inserted, and finally, the grid plates are installed layer by layer, ultimately forming the overall structure of the fuel basket 500. After the through-isolator 200 is pre-welded to the bottom of the spent fuel storage container, the assembled fuel basket 500 structure is hoisted into the cylinder of the spent fuel storage container. The through-isolator 200 occupies the position of one fuel storage unit in the adjacent axial region of the fuel basket 500, thus forming the main structure of the non-destructive sampling spent fuel storage container. Since the through-isolator sampling core design scheme of this invention requires one storage unit in the fuel basket 500, it can be applied to different types of spent fuel storage containers.

[0055] Please see Figures 1 to 23 The present invention also provides a spent fuel storage system, which includes a vertical non-destructive sampling spent fuel storage tank as described in any of the above embodiments, and a vertical concrete silo 600 for accommodating the spent fuel storage container. The vertical concrete silo 600 is a vertical structural unit with a cylindrical hollow cavity, and is provided with air outlets and air inlets at the top and bottom to provide structural protection and radiation shielding for the spent fuel storage container, and to discharge the decay heat released by the spent fuel to the atmosphere through natural air convection.

[0056] Please see Figures 1 to 23During operation, after the container body 100 and the through-isolation chamber 200 are welded together, test samples are first inserted into the storage bags 354 of the retention unit 350. Then, the retention unit 350 is placed inside the sampling cylinder 300, and the sampling cylinder 300 is sealed with a conical plug 340. The entire sampling cylinder 300 is then hoisted into the retention cavity of the through-isolation chamber 200, and then the shielding plug 410 and sealing plug 420 are installed in sequence for sealing. Then, the spent fuel assembly is loaded, and the top inner cover plate 130 and the top outer cover plate 140 are welded and sealed. Finally, the spent fuel storage container is hoisted into the vertical concrete silo 600 for long-term storage. When it is necessary to retrieve test samples for a ten-year periodic safety evaluation, the concrete cover plate 700 of the vertical concrete silo 600 is first hoisted and removed. Then, the sealing plug 420 and the shielding plug 410 are disassembled in sequence. Next, the sampling cylinder 300 is hoisted out of the sampling chamber. Finally, the samples on the sampling unit 350 are taken out for testing and aging analysis. The retrieval frequency is one set of samples every ten years. This invention enables the monitoring and rapid retrieval of samples from the high-temperature, high-irradiation representative area in the central region without damaging any part of the spent fuel storage container's structure or performing any operations on the storage container. It solves the international problem of sampling and aging analysis of welded sealed spent fuel storage containers.

[0057] Please see Figures 1 to 23 The present invention also proposes an operation method for a vertical non-destructive sampling spent fuel storage tank, the specific steps of which are as follows: First, after the container body 100 and the through-isolation chamber 200 are welded together, the sampling cylinder 300 containing the test sample is hoisted into the sample retention chamber through the opening of the through-isolation chamber 200. Specifically, during the factory manufacturing stage, the annular metal shell 110 and the bottom cover 120 are first welded together to form the basic structure of the main cylinder. Then, the inner and outer sides of the bottom of the hollow through-isolation chamber 200 are welded to the upper axial periphery of the bottom cover 120. Finally, the fuel basket 500 is hoisted into the container cylinder. Afterward, neutron absorber material samples, stainless steel or other material samples that can characterize the aging effect of key components of the cylinder are inserted one by one into the cavity of the storage bag 354 along the direction of the support rod 352 until each layer of storage bag 354 is filled from bottom to top. Then, the sampling unit 350 is placed inside the sampling cylinder 300, and the conical plug 340 is sealed to the sampling housing 310 by screwing on the thread. Finally, the entire sampling cylinder 300 is hoisted into the sampling cavity of the through isolation chamber 200.

[0058] Then, the shielding plug 410 and the sealing plug 420 are installed sequentially to seal the sample retention chamber. Specifically, first, the shielding plug 410 is hoisted to the constricting conical surface 250 at the top of the isolation chamber 200 using a long-handled screw-on tool. Automatic centering and fixing are achieved through the engagement of the tapered surface of the outer wall of the shielding plug 410 with the conical surface 250. Then, the sealing plug 420 is screwed into the threaded sealing surface 260 on the inner side of the top of the isolation chamber 200 using the screw-on tool. The threaded engagement achieves a seal, providing structural protection for the sampling cylinder 300.

[0059] After the spent fuel assemblies are loaded, the inner top cover plate 130 and the outer top cover plate 140 of the container body 100 are welded and sealed. Specifically, during fuel loading at the nuclear power plant site, the spent fuel assemblies are first loaded into the fuel basket 500, then the inner top cover plate 130 is installed. The first zone weld is completed between the through hole of the inner cover plate and the protective collar 220 and the outer cover welding surface 240 penetrating the isolation chamber 200. Then, the second zone circumferential weld is completed between the inner cover plate and the cylinder. After that, the outer top cover plate 140 is installed. The third zone weld is completed between the through hole of the outer cover plate and the inner cover welding surface 230 penetrating the isolation chamber 200. Finally, the fourth zone circumferential weld is completed between the outer cover plate and the cylinder. The above four top welds, combined with the two bottom welds from the manufacturing stage, form a complete sealed enclosure boundary. Finally, the inflation and drainage, vacuum drying, and helium filling operations are completed through the inflation port 134, the drainage port 135, and the matching quick-connect pipeline. The spent fuel storage container is then hoisted into the vertical concrete silo 600 for long-term storage.

[0060] When the test sample needs to be removed, first disassemble the sealing plug 420 and the shielding plug 410 in sequence, and then lift the sampling cylinder 300 out of the sample retention chamber through the opening. Specifically, first lift and remove the concrete cover plate 700 of the vertical concrete silo 600, then use a long-handled screwdriver to unscrew and remove the sealing plug 420 in reverse, and then use a tool with a grab to remove the shielding plug 410. After that, insert the lifting tool with the grab into the through-isolation chamber 200, grasp the spherical crown-shaped lifting handle 351 at the top of the sampling cylinder 300, and drive the support rod 352 through the lifting handle 351. The stop plate 355 on the support rod 352 lifts the conical plug 340, thereby lifting and removing the entire sampling cylinder 300 from the sample retention chamber. Finally, loosen the conical plug 340 from the sampling cylinder 300 by screwing it off, and directly remove the sample retention unit 350 from the cylinder. Take out a single sample from the corresponding layer for testing and aging analysis, following the method of taking out a row of samples every ten years.

[0061] In summary, the vertical non-destructive sampling spent fuel storage tank, storage system, and operation method of the present invention, by constructing a through-isolation chamber 200 on the sealed containment boundary of the container and placing the sampling cylinder 300 outside the sealed containment boundary, achieves the function of sampling from the top without cutting the container or damaging the sealing structure, significantly improving operational safety and economy; by arranging the through-isolation chamber 200 near the fuel unit location in the axial region, which is the area with the highest temperature and strongest radiation dose, the test sample is ensured to undergo the most severe environment, obtaining accurate and representative aging analysis data; by adopting a double-layer sealing structure of shielding plug 410 and sealing plug 420, which respectively undertake the functions of radiation shielding and structural protection, the sealing safety of the sampling chamber is ensured during long-term storage; by adopting a layered circumferential arrangement scheme of sampling unit 350, accurate monitoring of different positions of the axial active section of spent fuel is achieved, providing accurate data support for conducting periodic safety evaluations; by designing the protective collar 220, welding interference and cylinder deformation are effectively avoided, ensuring the welding quality and sealing reliability of the top through-area. This invention enables the monitoring and rapid retrieval of samples from representative high-temperature, high-irradiation areas in the central region without damaging any part of the spent fuel storage container's structure or performing any cutting operations. It solves the international challenge of sampling and aging analysis of welded, sealed spent fuel storage containers.

[0062] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0063] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0064] Throughout this specification, the terms "an embodiment," "embodiment," or "specific embodiment" refer to a particular feature, structure, or characteristic described in connection with an embodiment that is included in at least one embodiment of the invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the invention.

[0065] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0066] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0067] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0068] The above description of the embodiments shown in this invention (including the content set forth in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the invention to the precise forms disclosed herein. Although specific embodiments and examples of the invention have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the invention, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the invention in accordance with the above description of the embodiments described herein, and such modifications will be within the spirit and scope of the invention.

[0069] This document has generally described the systems and methods in detail to aid in understanding the invention. Furthermore, various specific details have been set forth to provide a general understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention can be practiced without one or more specific details, or using other means, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0070] Therefore, although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the scope of the foregoing disclosure, and it should be understood that in some cases, certain features of the invention may be adopted without departing from the scope and spirit of the invention and without corresponding use of other features. Thus, many modifications can be made to adapt a particular environment or material to the essential scope and spirit of the invention. The invention is not intended to be limited to the specific terminology used in the following claims and / or the specific embodiments disclosed as the best mode for carrying out the invention, but the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the invention will be defined only by the appended claims.

Claims

1. A vertical non-destructive sampling tank for spent fuel, characterized in that, include: The container body is a vertical cylindrical structure with a sealed enclosing cavity inside for accommodating spent fuel assemblies, and an opening is provided at the top of the container body. A through-isolation chamber is vertically disposed inside the container body along the axial direction of the container body, with its two ends sealed to the bottom and top of the container body, respectively. A sample retention chamber is formed inside the through-isolation chamber, which is isolated from the sealed enclosure and communicates with the external atmospheric environment only through the opening. A sampling tube, housed within the sample retention cavity, is used to store test samples; A sealing assembly is installed at the opening to seal the sample retention chamber.

2. The vertical non-destructive sampling spent fuel storage tank according to claim 1, characterized in that, The container body includes a shell, a bottom cover, an inner top cover, and an outer top cover, and the sealed enclosing cavity is defined by the shell, the bottom cover, the inner top cover, and the outer top cover. The bottom end of the through-isolation chamber is sealed and welded to the bottom cover, and the top end passes through the inner top cover plate and the outer top cover plate in sequence and is sealed and welded to them respectively.

3. The vertical non-destructive sampling spent fuel storage tank according to claim 2, characterized in that, The through-hole isolation chamber includes a main chamber cylinder, which is a hollow cylindrical structure with a thick upper wall and a thin lower wall. Its bottom end is welded to the bottom cover on both the inner and outer sides to form a double seal.

4. The vertical non-destructive sampling spent fuel storage tank according to claim 3, characterized in that, The top inner wall of the main chamber is provided with a tapered surface with a narrowing diameter, which is used to support and position the sealing assembly.

5. The vertical non-destructive sampling spent fuel storage tank according to claim 4, characterized in that, The inner top of the main chamber has a threaded sealing surface above the conical surface, which is used to cooperate with the sealing assembly to achieve a threaded seal.

6. The vertical non-destructive sampling spent fuel storage tank according to claim 3, characterized in that, The through-hole isolation chamber also includes a protective collar, which is nested around the top outer periphery of the main chamber cylinder and welded and fixed to the upper annular area of ​​the main chamber cylinder.

7. The vertical non-destructive sampling spent fuel storage tank according to claim 2, characterized in that, The top inner cover plate is a metal cover plate with a first through hole in the center. The first through hole is nested around the outer periphery of the through isolation chamber. The outer edge of the top inner cover plate is sealed to the shell by a first circumferential weld. The edge of the first through hole is sealed to the through isolation chamber by a second circumferential weld.

8. The vertical non-destructive sampling spent fuel storage tank according to claim 7, characterized in that, The top outer cover plate is a metal cover plate with a second through hole in the center. The second through hole is nested around the outer periphery of the through isolation chamber. The edge of the second through hole is sealed to the through isolation chamber by a third ring weld. The outer edge of the top outer cover plate is sealed to the shell by a fourth ring weld.

9. The vertical non-destructive sampling spent fuel storage tank according to claim 2, characterized in that, The top inner cover plate is also provided with an inflation hole, a drainage hole, and quick connectors and drainage pipes that match the inflation hole and drainage hole, for realizing the inflation and drainage, vacuum drying and helium filling operations of the sealed cavity.

10. The vertical non-destructive sampling spent fuel storage tank according to claim 1, characterized in that, The sampling tube includes: A sampling housing is disposed within the sample retention chamber; A conical plug is installed at one end of the sampling housing; A sample retention unit is housed inside the sampling housing.

11. The vertical non-destructive sampling spent fuel storage tank according to claim 10, characterized in that, The sample retention unit includes: A support rod is installed inside the sampling housing; A lifting handle is provided at the top of the support rod; A base is located at the bottom end of the supporting rod; The storage bag is fixed to the support rod. A stop plate is fixed to the upper part of the support rod and located at the lower end of the conical plug. The diameter of the stop plate is larger than the diameter of the central through hole of the conical plug, so that when the lifting handle is lifted, the conical plug is supported by the stop plate, thereby removing the entire sampling cylinder from the sample retention chamber.

12. The vertical non-destructive sampling spent fuel storage tank according to claim 11, characterized in that, The storage bags are arranged in layers along the axial direction of the support rod, and multiple storage bags are evenly distributed in each layer along the circumference. Each storage bag is a hollow bag with an opening at the top and sealed at the bottom and around the perimeter, used to store test samples.

13. The vertical non-destructive sampling spent fuel storage tank according to claim 12, characterized in that, The storage bag is made of a low-activation material.

14. The vertical non-destructive sampling spent fuel storage tank according to claim 1, characterized in that, The sealing assembly includes a sealing plug and a shielding plug. The shielding plug is freely located inside the top of the through-hole isolation chamber to provide radiation shielding. The sealing plug is installed above the shielding plug and seals against the inner wall of the top of the through-hole isolation chamber to provide structural protection and a top seal.

15. The vertical non-destructive sampling spent fuel storage tank according to claim 14, characterized in that, The shielding plug is a columnar structure with a gradually decreasing diameter, and its outer wall matches the conical surface that penetrates the inner wall of the isolation chamber. The top of the shielding plug is provided with a first screwing operation part and a first positioning hole, which are used to cooperate with external operating tools to achieve remote picking and placing.

16. The vertical non-destructive sampling spent fuel storage tank according to claim 14, characterized in that, The sealing plug is a cylindrical threaded sealing structure with external threads on its outer circumference, which are used to mate with the threaded sealing surface that penetrates the inner wall of the top of the isolation chamber. The top of the sealing plug is provided with a second screwing operation part and a second positioning hole, which are used to cooperate with external operating tools to achieve remote disassembly and assembly.

17. The vertical non-destructive sampling spent fuel storage tank according to claim 2, characterized in that, The sealed containment cavity is equipped with a fuel basket, which consists of multiple fuel storage units. Each fuel storage unit is used to store a set of spent fuel assemblies. The through-barrier compartment occupies the position of one fuel storage unit in the fuel basket adjacent to the central region.

18. A spent fuel storage system, characterized in that, It includes a spent fuel storage container as described in any one of claims 1 to 17, and a vertical concrete silo for housing the spent fuel storage container.

19. An operating method for a vertical non-destructive sampling spent fuel storage tank, characterized in that, include: After the container body and the through-isolation chamber are welded together, the sampling tube containing the test sample is hoisted into the sample retention chamber through the opening of the through-isolation chamber. Install the shielding plug and the sealing plug in sequence to seal the sample retention chamber; After the spent fuel assembly is loaded, the inner and outer top cover plates of the container body are welded and sealed. When it is necessary to remove the test sample, first remove the sealing plug and the shielding plug in sequence, and then lift the sampling tube out of the sample retention cavity through the opening.

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