Spent fuel wet transportation container

Abstract

The invention relates to the technical field of nuclear, in particular to a spent fuel wet transport container which comprises a containing cavity used for containing a spent fuel assembly, a pressure cavity is formed in the wall of the spent fuel wet transport container, protective gas with preset pressure is contained in the pressure cavity, and a partition wall part is arranged between the pressure cavity and the containing cavity. And the one-way pressure valve is arranged on the partition wall part, can be opened when the internal pressure of the accommodating cavity is higher than the preset pressure, and is communicated with the accommodating cavity and the pressure cavity. The spent fuel wet transportation container is suitable for wet transportation of spent fuel assemblies, the pressure cavity and the one-way pressure valve can play a role in pressure relief, the internal pressure of the containing cavity is reduced, and the structural safety of the spent fuel wet transportation container is guaranteed; and for the high-fuel-consumption spent fuel assembly, vacuum drying does not need to be carried out, fuel cladding performance degradation caused by rapid temperature rise and cold and hot circulation after secondary water entry is avoided, and the technical problem of secondary water entry of the high-fuel-consumption spent fuel assembly is solved.

Description

Technical Field

[0001] This application relates to the field of nuclear technology, and particularly to a wet transportation container for spent fuel. Background Art

[0002] Currently, the transportation containers for spent fuel are generally dry transportation containers. Dry transportation means that the spent fuel assemblies need to be vacuum dried, and the transportation is carried out after the liquid in the container is removed. For high burnup spent fuel assemblies, the temperature of high burnup spent fuel assemblies will rise sharply during the vacuum drying process. After re - immersion in water, due to the thermal cycling, the cladding performance of high burnup spent fuel assemblies will deteriorate, resulting in the destruction of structural integrity and even the leakage of radioactive gases.

[0003] Therefore, how to solve the technical problem of re - immersion in water of high burnup spent fuel assemblies has become an urgent technical problem for those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a wet transportation container for spent fuel to solve the technical problem of re - immersion in water of high burnup spent fuel assemblies.

[0005] To solve the above - mentioned technical problem, this application provides a wet transportation container for spent fuel. The wet transportation container for spent fuel includes a receiving cavity for accommodating spent fuel assemblies. A pressure cavity is arranged inside the wall of the wet transportation container for spent fuel. The inside of the pressure cavity contains a protective gas with a preset pressure. There is a partition wall portion between the pressure cavity and the receiving cavity. The wet transportation container for spent fuel further includes a one - way pressure valve. The one - way pressure valve is arranged on the partition wall portion. The one - way pressure valve can be opened when the internal pressure of the receiving cavity is higher than the preset pressure, and it connects the receiving cavity and the pressure cavity.

[0006] The wet transportation container for spent fuel of this application is applicable to the wet transportation of spent fuel assemblies. Wet transportation means that the spent fuel assemblies are not vacuum dried, and the spent fuel assemblies and liquid are transported together. During the transportation process, the spent fuel assemblies will continuously release heat, and the liquid will vaporize under the heating of the spent fuel assemblies, causing the internal pressure of the receiving cavity to rise. However, in the wet transportation container for spent fuel of this application, a pressure cavity is arranged inside the wall. The inside of the pressure cavity contains a protective gas with a preset pressure. There is a partition wall portion between the pressure cavity and the receiving cavity. The one - way pressure valve is arranged on the partition wall portion. When the internal pressure of the receiving cavity is higher than the preset pressure, the one - way pressure valve can be opened to connect the receiving cavity and the pressure cavity, playing a role in pressure relief, reducing the internal pressure of the receiving cavity, and ensuring the structural safety of the wet transportation container for spent fuel.

[0007] The spent fuel wet transportation container of the present application can be used for the wet transportation of high burn-up spent fuel assemblies and low burn-up spent fuel assemblies. Especially for high burn-up spent fuel assemblies, wet transportation means that there is no need to perform vacuum drying on high burn-up spent fuel assemblies, which can effectively avoid the sharp temperature rise during the vacuum drying of high burn-up spent fuel assemblies and the deterioration of the fuel cladding performance caused by the thermal cycling after re-immersion in water, thus solving the technical problem of re-immersion of high burn-up spent fuel assemblies.

[0008] Optionally, the spent fuel wet transportation container includes an inner cover, the pressure chamber is arranged in the inner cover, and the wall portion of the inner cover located inside the pressure chamber forms the partition wall portion.

[0009] Optionally, the value range of the preset pressure is: 0.1 bar - 1 bar.

[0010] Optionally, a neutron shielding layer is arranged inside the wall of the peripheral wall of the spent fuel wet transportation container, and the neutron shielding layer is an annular structure surrounding the accommodation chamber;

[0011] Or, the neutron shielding layer includes a plurality of neutron shielding rods, the neutron shielding rods extend along the axial direction of the spent fuel wet transportation container, part of the neutron shielding rods are distributed along the circumferential direction of the spent fuel wet transportation container and enclose an inner shielding ring, part of the neutron shielding rods are distributed along the circumferential direction of the spent fuel wet transportation container to enclose an outer shielding ring, the inner shielding ring is located inside the outer shielding ring, and any one of the neutron shielding rods in the outer shielding ring is located between two adjacent neutron shielding rods in the inner shielding ring.

[0012] Optionally, heat dissipation fins are arranged on the outer side of the peripheral wall of the spent fuel wet transportation container.

[0013] Optionally, the heat dissipation fins extend along the axial direction of the spent fuel wet transportation container and are distributed along the circumferential direction of the spent fuel wet transportation container;

[0014] Or, the heat dissipation fins extend along the circumferential direction of the spent fuel wet transportation container and are distributed along the axial direction of the spent fuel wet transportation container.

[0015] Optionally, the spent fuel wet transportation container includes:

[0016] A container body, the container body is a hollow structure with one end open;

[0017] An inner cover, connected to the open end of the container body, and the container body and the inner cover enclose the accommodation chamber;

[0018] An outer cover, connected to the open end of the container body and located outside the inner cover;

[0019] The materials of the container body, the inner cover and the outer cover are forged steel.

[0020] Optionally, the spent fuel wet transportation container includes:

[0021] A hanging basket, which is arranged inside the accommodating cavity. The hanging basket includes fuel pipes, and the material of the fuel pipes is boron steel.

[0022] Optionally, the spent fuel wet transportation container further includes shock absorbers located at both axial ends. In the cross-section of the shock absorbers, the outer contour of the shock absorbers is circular or square.

[0023] Optionally, the spent fuel wet transportation container further includes shock absorbers located at both axial ends. The shock absorbers include main shock-absorbing parts, and the material of the main shock-absorbing parts is honeycomb aluminum.

[0024] Optionally, the spent fuel wet transportation container further includes shock absorbers located at both axial ends. The shock absorbers include main shock-absorbing parts, and the material of the main shock-absorbing parts is wood.

[0025] Optionally, the shock absorbers further include:

[0026] An outer ring part. The main shock-absorbing part of the outer ring part includes a first shock-absorbing part, a second shock-absorbing part and a third shock-absorbing part that are sequentially connected along the axial direction;

[0027] A column part, which is connected to the middle of the outer ring part. A cavity structure with an inner end opening is formed between the column part and the outer ring part. The column part protrudes from the outer surface of the outer ring part. The main shock-absorbing part of the column part includes a fourth shock-absorbing part, a fifth shock-absorbing part and a sixth shock-absorbing part that are sequentially connected along the axial direction;

[0028] The axial dimensions of the first shock-absorbing part, the second shock-absorbing part and the third shock-absorbing part gradually decrease. The wood grain direction of the first shock-absorbing part is perpendicular to the axial direction of the spent fuel wet transportation container;

[0029] The wood grain directions of the fourth shock-absorbing part and the fifth shock-absorbing part are parallel to the axial direction of the spent fuel wet transportation container;

[0030] The wood grain directions of the third shock-absorbing part and the sixth shock-absorbing part are arranged at an acute angle to the axial direction of the spent fuel wet transportation container;

[0031] The wood grain direction of the second shock-absorbing part is perpendicular to the axial direction of the spent fuel wet transportation container, or the wood grain direction of the second shock-absorbing part is parallel to the axial direction of the spent fuel wet transportation container. Description of the Drawings

[0032] Figure 1Subassembly drawing of a specific embodiment of the spent fuel wet transportation container provided by this application;

[0033] Figure 2 is Figure 1 Cross-sectional view of the inner cover in the spent fuel wet transportation container;

[0034] Figure 3 is Figure 1 Schematic structural diagram of the container body of the spent fuel wet transportation container with a partial cutaway;

[0035] Figure 4 Schematic structural diagram of the container body with a partial cutaway in another specific embodiment of the spent fuel wet transportation container provided by this application;

[0036] Figure 5 is Figure 4 Cross-sectional view of the container body;

[0037] Figure 6 is Figure 1 Schematic structural diagram of the outer cover of the spent fuel wet transportation container;

[0038] Figure 7 is Figure 6 Cross-sectional view of the outer cover;

[0039] Figure 8 is Figure 1 Schematic structural diagram of the shock absorber in the spent fuel wet transportation container;

[0040] Figure 9 is Figure 8 Cross-sectional view of the shock absorber;

[0041] Figure 10 Schematic structural diagram of the shock absorber in another specific embodiment of the spent fuel wet transportation container provided by this application;

[0042] Figure 11 is Figure 10 Cross-sectional view of the shock absorber;

[0043] Among them, Figures 1 - 11 the reference signs in the

[0044] 1 - One - way pressure valve; 2 - Container body; 2 - 1 - Step wall part; 2 - 1a - Second connection hole; 2 - 2 - Closed end wall; 2 - 3 - Open end wall; 2 - 3a - Fourth connection hole; 3 - Inner cover; 3a - First connection hole; 4 - Neutron shielding layer; 4 - 1 - Shielding rod; 5 - Hoisting grab head; 6 - Heat dissipation fins; 7 - Outer cover; 7a - Third connection hole; 7 - 1 - Thick section; 7 - 2 - Thin section; 7 - 3 - Step part; 8 - Suspension basket; 9 - 1 - Upper trunnion; 9 - 2 - Lower trunnion; 10 - Shock absorber; 10 - 1 - Main shock - absorbing part; 10 - 11 - First shock - absorbing part; 10 - 12 - Second shock - absorbing part; 10 - 13 - Third shock - absorbing part; 10 - 14 - Fourth shock - absorbing part; 10 - 15 - Fifth shock - absorbing part; 10 - 16 - Sixth shock - absorbing part; 10 - 2 - Housing part; 10 - A Outer ring part; 10 - B - Column part; 10 - C - Sleeve

[0045] A - Accommodation cavity; B - Pressure cavity; 1A - Partition wall part. Detailed implementation mode

[0046] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts.

[0047] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same type, and the number of objects is not limited. For example, the first object can be one or multiple. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0048] It should be understood that "some embodiments" mentioned throughout the specification means that specific features, structures, or characteristics related to the embodiments are included in at least one embodiment of the present application. Therefore, "in some embodiments" appearing throughout the specification does not necessarily refer to the same embodiments. In addition, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0049] In the description of this article, unless otherwise clearly specified and defined, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this article can be understood according to specific circumstances.

[0050] Please refer to Figures 1 - 3 , Figure 1 which is a sectional view of a specific embodiment of the spent fuel wet transportation container provided by this application; Figure 2 is Figure 1 a cross-sectional view of the inner cover in the spent fuel wet transportation container; Figure 3 is Figure 1 a schematic structural view of a partially cut-open container body in the spent fuel wet transportation container.

[0051] Currently, domestic spent fuel wet transportation containers are all dry transportation containers. Dry transportation means that the spent fuel assemblies need to be vacuum dried, and the transportation is carried out after the liquid in the container is removed. Especially for high burnup spent fuel assemblies, the temperature of high burnup spent fuel assemblies will rise sharply during the vacuum drying process. After re-entering water, the cladding performance of high burnup spent fuel assemblies will deteriorate due to thermal cycling, resulting in the destruction of structural integrity and even the leakage of radioactive gas.

[0052] To solve the technical problem of the re-entry of high burnup spent fuel assemblies into water, the embodiments of this application provide a spent fuel wet transportation container. The spent fuel wet transportation container includes an accommodation cavity A for accommodating the spent fuel assemblies. A pressure cavity B is provided inside the wall of the spent fuel wet transportation container. The pressure cavity B contains a protective gas with a preset pressure inside. There is a partition part 1A between the pressure cavity B and the accommodation cavity A. The spent fuel wet transportation container further includes a one-way pressure valve 1. The one-way pressure valve 1 is provided on the partition part 1A. The one-way pressure valve 1 can be opened when the internal pressure of the accommodation cavity A is higher than the preset pressure to connect the accommodation cavity A and the pressure cavity B.

[0053] The spent fuel wet transportation container of the embodiment of the present application is applicable to the wet transportation of spent fuel assemblies. Wet transportation means that the spent fuel assemblies are not vacuum-dried, and the spent fuel assemblies and liquid are transported together. During the transportation process, the spent fuel assemblies will continuously release heat, and the liquid will vaporize under the heating of the spent fuel assemblies, causing the pressure inside the accommodation chamber A to rise. And there is a pressure chamber B provided in the wall of the spent fuel wet transportation container of the present application. The inside of the pressure chamber B contains a protective gas with a preset pressure. There is a partition wall part 1A between the pressure chamber B and the accommodation chamber A. A one-way pressure valve 1 is provided on the partition wall part 1A. When the pressure inside the accommodation chamber A is higher than the preset pressure, the one-way pressure valve 1 can be opened to connect the pressure chamber B and the accommodation chamber A, playing a role in pressure relief, reducing the pressure inside the accommodation chamber A, and ensuring the structural safety of the spent fuel wet transportation container.

[0054] The spent fuel wet transportation container of the embodiment of the present application can be used for the wet transportation of high burnup spent fuel assemblies and can also be used for the wet transportation of low burnup spent fuel assemblies. Especially for high burnup spent fuel assemblies, wet transportation means that there is no need to vacuum-dry the high burnup spent fuel assemblies, which can effectively avoid the sharp temperature rise during the vacuum drying of high burnup spent fuel assemblies and the deterioration of the fuel cladding performance caused by the thermal cycling after re-immersion in water, thus solving the technical problem of re-immersion in water of high burnup spent fuel assemblies.

[0055] Among them, a high burnup assembly refers to a spent fuel assembly with a burnup higher than 45000 MWD / tU, and a low burnup assembly refers to a spent fuel assembly with a burnup lower than 45000 MWD / tU.

[0056] Among them, the protective gas inside the pressure chamber B can be an inert gas, such as argon, helium, etc.

[0057] As Figure 1 shown, the spent fuel wet transportation container of the embodiment of the present application includes:

[0058] A container body 2, and the container body 2 is a hollow structure with one end open;

[0059] An inner cover 3, which is connected to the open end of the container body 2, and the container body 2 and the inner cover 3 enclose an accommodation chamber A for accommodating the spent fuel assemblies.

[0060] As Figure 2 shown, in some embodiments of the present application, the pressure chamber B is provided in the inner cover 3, and the wall part of the inner cover 3 located inside the pressure chamber B forms the partition wall part 1A; among them, the side close to the accommodation chamber A is the inner side.

[0061] Compared with the container body 2, the inner cover 3 has a simpler structure. The pressure chamber B is arranged in the inner cover 3, which is more convenient for the forming of the pressure chamber B. The one-way pressure valve 1 is connected to the inner cover 3, which is convenient for the assembly, detection, replacement and maintenance of the one-way pressure valve 1. The inner cover 3 integrates the pressure relief function as an independent module, which is convenient for standardized production and quick replacement.

[0062] In some embodiments of the present application, the value range of the preset pressure is: 0.1 bar - 1 bar.

[0063] It has been verified that if the preset pressure is lower than 0.1 bar, the pressure inside the pressure chamber B is too low, and the pressure chamber B part of the inner cover 3 is in a large negative pressure state for a long time, and the amount of protective gas is insufficient, resulting in the deformation, rust and even performance degradation of the inner cover 3. When the spent fuel assembly is loaded into the spent fuel wet transportation container, the pressure inside the accommodation chamber A is about 1 bar. If the preset pressure is higher than 1 bar, since the inside of the pressure chamber B already contains a large pressure, the pressure relief amount of the high-pressure gas inside the accommodation chamber A will be reduced, and the pressure relief efficiency will be lowered. Based on this, in some embodiments of the present application, the preset pressure has the above value range, and the preset pressure can specifically take values such as 0.1 bar, 0.3 bar, 0.5 bar, 0.7 bar, 1 bar, etc., which can not only ensure the pressure relief efficiency, but also avoid the inner cover 3 being in a large negative pressure for a long time and ensure the structural stability of the inner cover 3.

[0064] From Figure 2 It can be seen that a neutron shielding layer 4 is further arranged on the inner wall of the inner cover 3 outside the accommodation chamber A to achieve the shielding protection of the neutrons of the spent fuel; wherein, the side away from the accommodation chamber A is the outside.

[0065] From Figure 2 It can be seen that a lifting hook gripper 5 is connected to the outer wall of the inner cover 3, and the lifting hook gripper 5 is used for the lifting tool to apply force when opening the inner cover 3.

[0066] From Figure 1 And Figure 2 It can be seen that a first connection hole 3a is arranged at the edge of the inner cover 3, and the inner part of the container body 2 has a stepped wall part 2-1 near the open end. A second connection hole 2-1a is arranged at the corresponding position of the stepped wall part 2-1 and the first connection hole 3a. The connecting piece passes through the corresponding first connection hole 3a and second connection hole 2-1a to realize the connection between the inner cover 3 and the container body 2. The number of the first connection holes 3a and the second connection holes 2-1a is multiple and distributed circumferentially to ensure the reliable connection between the inner cover 3 and the container body 2.

[0067] Please continue to refer to Figure 3, in some embodiments of the present application, a neutron shielding layer 4 is provided inside the wall of the peripheral wall of the spent fuel wet transportation container, that is, inside the wall of the peripheral wall of the container body 2. The neutron shielding layer 4 includes a plurality of neutron shielding rods 4-1. The neutron shielding rods 4-1 extend along the axial direction of the spent fuel wet transportation container. Some of the neutron shielding rods 4-1 are distributed circumferentially along the spent fuel wet transportation container and enclose an inner shielding ring. Some of the neutron shielding rods 4-1 are distributed circumferentially along the spent fuel wet transportation container to enclose an outer shielding ring. The inner shielding ring is located inside the outer shielding ring. Any one of the neutron shielding rods 4-1 in the outer shielding ring is located between two adjacent neutron shielding rods 4-1 in the inner shielding ring.

[0068] Wherein, the axial direction of the spent fuel wet transportation container is the length direction of the spent fuel wet transportation container.

[0069] With the above arrangement, the neutron shielding layer 4 is used to absorb and attenuate the neutron radiation released by the spent fuel assembly, reducing the radiation hazard to the environment and personnel; the neutron shielding layer 4 adopts the structural form of a plurality of neutron shielding rods 4-1. Any one of the neutron shielding rods 4-1 in the outer shielding ring is located between two adjacent neutron shielding rods 4-1 in the inner shielding ring, that is, any one of the neutron shielding rods 4-1 in the outer shielding ring can fill the gap between two adjacent neutron shielding rods 4-1 in the inner shielding ring. Thus, the plurality of neutron shielding rods 4-1 are circumferentially wrapped around the outer periphery of the accommodation cavity A, providing a uniform shielding effect and avoiding the occurrence of shielding weak points. In addition, the neutron shielding rods 4-1 can be prefabricated in advance and their performance measured, improving the manufacturing progress of the spent fuel wet transportation container.

[0070] Please continue to refer to Figure 4 and Figure 5 , Figure 4 Figure 1 Another schematic structural diagram of a partial cross-section of the container body in the spent fuel wet transportation container; Figure 5 is Figure 4 a cross-sectional view of the container body.

[0071] In some embodiments of the present application, a neutron shielding layer 4 is provided inside the wall of the peripheral wall of the spent fuel wet transportation container. The neutron shielding layer 4 is an annular structure surrounding the accommodation cavity A.

[0072] With the above arrangement, the neutron shielding layer 4 is used to absorb and attenuate the neutron radiation released by the spent fuel assembly, reducing the radiation hazard to the environment and personnel; the neutron shielding layer 4 is an annular structure and surrounds the entire accommodation cavity A, which can provide a uniform shielding effect and avoid the occurrence of shielding weak points.

[0073] When assembling the neutron shielding layer 4, an installation chamber can be reserved inside the wall of the circumferential wall of the wet transportation container for spent fuel, and the molten neutron shielding material can be injected into the reserved installation chamber by means of pouring. Alternatively, an installation chamber can be machined inside the wall of the circumferential wall of the wet transportation container for spent fuel, and the solid neutron shielding material can be placed into the installation chamber by means of assembly.

[0074] As Figure 5 shown, the end wall of the container body 2 opposite to the open end is a closed end wall 2-2, and a neutron shielding layer 4 is also provided inside the wall of the closed end wall 2-2 to achieve shielding protection against the neutron radiation released by the spent fuel assembly.

[0075] Among them, the material of the neutron shielding layer 4 includes but is not limited to boron-containing polyethylene.

[0076] Please continue to refer to Figures 3 - 5 , in some embodiments of the present application, heat dissipation fins 6 are provided on the outer side of the circumferential wall of the wet transportation container for spent fuel.

[0077] During the transportation process, the spent fuel assembly continuously generates heat. The provision of the heat dissipation fins 6 helps to increase the surface area of the wet transportation container for spent fuel, and quickly dissipate the heat generated by the spent fuel assembly into the surrounding environment, so as to keep the temperature inside the wet transportation container for spent fuel within a safe range.

[0078] Among them, the heat dissipation fins 6 can be arranged in a variety of ways. Specifically:

[0079] As Figure 3 shown, in some embodiments, the heat dissipation fins 6 extend along the axial direction of the wet transportation container for spent fuel and are distributed along the circumferential direction of the wet transportation container for spent fuel.

[0080] With the above arrangement, the heat dissipation fins 6 extending along the axial direction of the wet transportation container for spent fuel are conducive to the longitudinal transfer of heat, thereby enhancing the heat dissipation capacity of the wet transportation container for spent fuel in the axial direction; the heat dissipation fins 6 being distributed along the circumferential direction of the wet transportation container for spent fuel can ensure that the temperature distribution in the circumferential direction of the wet transportation container for spent fuel is more uniform and avoid local overheating.

[0081] As Figure 4 shown, in some other embodiments, the heat dissipation fins 6 extend along the circumferential direction of the wet transportation container for spent fuel and are distributed along the axial direction of the wet transportation container for spent fuel.

[0082] With the above arrangement, the heat dissipation fins 6 extending along the circumferential direction of the wet transportation container for spent fuel are conducive to the circumferential transfer of heat, thereby enhancing the heat dissipation capacity of the wet transportation container for spent fuel in the circumferential direction; the heat dissipation fins 6 being distributed along the axial direction of the wet transportation container for spent fuel can ensure that the temperature distribution in the axial direction of the wet transportation container for spent fuel is more uniform and avoid local overheating.

[0083] Among them, different setting methods of the neutron shielding layer 4 and different setting methods of the heat dissipation fins 6 can be arbitrarily combined. For example, in Figure 3 the embodiment of Figure 4 , the neutron shielding layer 4 adopts the structural form of neutron shielding rods 4-1, and the heat dissipation fins 6 extend along the axial direction of the spent fuel wet transportation container; in

[0084] Please refer to Figure 1 , Figures 6 - 7 , Figure 6 which is Figure 1 a schematic structural view of the outer cover of the spent fuel wet transportation container; Figure 7 which is Figure 6 a cross-sectional view of the outer cover.

[0085] In some embodiments of the present application, the spent fuel wet transportation container further includes:

[0086] An outer cover 7, connected to the open end of the container body 2 and located outside the inner cover 3, serving to shield the γ-rays of the spent fuel assembly.

[0087] As Figure 1 shown, a third connection hole 7a is provided at the edge of the outer cover 7, and a fourth connection hole 2-3a is correspondingly provided on the open end wall 2-3 of the container body 2. A connecting piece passes through the corresponding third connection hole 7a and fourth connection hole 2-3a to realize the connection between the outer cover 7 and the container body 2.

[0088] As Figure 7 shown, the outer cover 7 includes a thick section 7-1 and a thin section 7-2. The thin section 7-2 is connected to the inside of the thick section 7-1. A stepped portion 7-3 facing the inner end is formed between the thick section 7-1 and the thin section 7-2. The spent fuel wet transportation container further includes a sealing ring (not shown in the figure). The sealing ring is sleeved on the thin section 7-2 and pressed between the stepped portion 7-3 and the open end wall 2-3 of the container body 2 to enhance the sealing performance between the outer cover 7 and the container body 2, so that the outer cover 7 seals the container body 2 more tightly and safely. The sealing ring is provided with a through hole at the corresponding position of the third connection hole 7a for the connecting piece to pass through.

[0089] Furthermore, in some embodiments of the present application, the materials of the container body 2, the inner cover 3 and the outer cover 7 are forged steel.

[0090] With the above settings, the container body 2, the inner lid 3 and the outer lid 7 are made of forged steel to achieve the shielding of γ rays from spent fuel assemblies. Different from the existing wet transportation containers for spent fuel that adopt a layered structure of an inner cylinder + an outer shell + lead filling in the middle cavity, it can reduce the manufacturing difficulty of wet transportation containers for spent fuel, improve the manufacturing quality of wet transportation containers for spent fuel, and reduce the uncertainty in the production and manufacturing of wet transportation containers for spent fuel, especially in the lead filling process.

[0091] As Figure 5 shown, in the embodiment of the present application, the container body 2 is a split structure along the axial direction and is then welded together to form an integral structure. In this way, the forming convenience of the container body 2 is improved, and the assembly convenience of the neutron shielding layer 4 is improved.

[0092] Please continue to refer to Figure 1 , in some embodiments of the present application, the wet transportation container for spent fuel includes:

[0093] A hanging basket 8, which is arranged inside the accommodation cavity A and serves to install the spent fuel assembly. The hanging basket 8 includes a fuel tube (not shown in the figure), and the material of the fuel tube is boron steel.

[0094] Different from the sandwich structure of stainless steel + neutron absorbing material + stainless steel for the fuel tube in the existing wet transportation containers for spent fuel, the fuel tube in the embodiment of the present application is made of boron steel, which can simultaneously meet the support and neutron shielding functions of the spent fuel assembly and reduce the manufacturing difficulty of the fuel tube.

[0095] Please continue to refer to Figure 1 , the wet transportation container for spent fuel further includes:

[0096] An upper trunnion 9-1, which is connected to the outer wall of the container body 2 and is close to the open end of the container body 2;

[0097] A lower trunnion 9-2, which is connected to the outer wall of the container body 2 and is close to the closed end of the container body 2.

[0098] The upper trunnion 9-1 is used for hoisting the container body 2 and, in cooperation with the lower trunnion 9-2, for the horizontal / vertical attitude conversion of the container body 2.

[0099] Among them, the upper / lower trunnions can be connected to the container body 2 by welding or by threaded connection, and no limitation is made here.

[0100] Please continue to refer to Figure 1 , Figures 8 - 11 , Figure 8 is Figure 1 a schematic structural diagram of a shock absorber in a wet transportation container for spent fuel; Figure 9 is Figure 8 a cross-sectional view of the shock absorber; Figure 10This is a schematic structural diagram of a shock absorber in another specific embodiment of the spent fuel wet transport container provided in this application; Figure 11 for Figure 10 Cross-sectional view of a shock absorber.

[0101] In some embodiments of the present application, the spent fuel wet transport container further includes shock absorbers 10 located at both ends of the axial direction. In the cross section of the shock absorber 10, the outer contour of the shock absorber 10 is circular or square.

[0102] As configured above, the main function of the shock absorber 10 is shock absorption to reduce the impact load when falling. The outer contour of the shock absorber 10 is circular, which can better adapt to the cylindrical shape of the container body 2; the outer contour of the shock absorber 10 is square, which increases the volume of the shock absorbing material under the premise of the same inscribed diameter, and has a better shock absorption effect.

[0103] like Figure 9 As shown, in some embodiments of the present application, the shock absorber 10 includes a main shock absorbing part 10 - 1 , and the material of the main shock absorbing part 10 - 1 is honeycomb aluminum.

[0104] The main shock absorbing part 10-1 can be integrally formed by processing a honeycomb aluminum ingot. Honeycomb aluminum can effectively absorb and disperse the impact force when subjected to force, improve the shock absorbing effect, and enhance the seismic performance of the spent fuel wet transport container.

[0105] like Figure 11 As shown, in some other embodiments of the present application, the material of the main shock absorbing part 10 - 1 is wood.

[0106] As configured above, wood has good energy absorption capacity, can effectively absorb and disperse impact force, and reduce the impact of vibration and impact on spent fuel wet transport containers; moreover, wood has good structural stability and lower cost.

[0107] Among them, the optional wood materials for the main shock absorbing part 10-1 include balsa wood, mahogany, domestic fir, metasequoia, paulownia and the like.

[0108] Please continue to refer to Figure 11 In some embodiments of the present application, the shock absorber 10 includes:

[0109] The outer ring portion 10-A, the main shock absorbing portion 10-1 of the outer ring portion 10-A comprises a first shock absorbing portion 10-11, a second shock absorbing portion 10-12 and a third shock absorbing portion 10-13 which are sequentially connected along the axial direction;

[0110] The column part 10-B is connected to the middle part of the outer ring part 10-A. A cavity structure with an open inner end is formed between the column part 10-B and the outer ring part 10-A. The column part 10-B protrudes from the outer surface of the outer ring part 10-A. The main shock-absorbing part 10-1 of the column part 10-B includes a fourth shock-absorbing part 10-14, a fifth shock-absorbing part 10-15, and a sixth shock-absorbing part 10-16 that are sequentially connected along the axial direction.

[0111] The axial dimensions of the first shock-absorbing part 10-11, the second shock-absorbing part 10-12, and the third shock-absorbing part 10-13 gradually decrease. The wood grain direction of the first shock-absorbing part 10-11 is perpendicular to the axial direction of the spent fuel wet transportation container.

[0112] The wood grain directions of the fourth shock-absorbing part 10-14 and the fifth shock-absorbing part 10-15 are parallel to the axial direction of the spent fuel wet transportation container.

[0113] The wood grain directions of the third shock-absorbing part 10-13 and the sixth shock-absorbing part 10-16 are set at an acute angle to the axial direction of the spent fuel wet transportation container.

[0114] The wood grain direction of the second shock-absorbing part 10-12 is perpendicular to the axial direction of the spent fuel wet transportation container, or the wood grain direction of the second shock-absorbing part 10-12 is parallel to the axial direction of the spent fuel wet transportation container.

[0115] With the above settings, the axial dimensions of the first shock-absorbing part 10-11, the second shock-absorbing part 10-12, and the third shock-absorbing part 10-13 gradually decrease. Both the first shock-absorbing part 10-11 and the second shock-absorbing part 10-12 are used to bear the lateral impact of the spent fuel wet transportation container. The axial dimension of the first shock-absorbing part 10-11 is greater than that of the second shock-absorbing part 10-12. Compared with the second shock-absorbing part 10-12, the first shock-absorbing part 10-11 plays a major role in bearing the lateral impact. When the grain direction of the first shock-absorbing part 10-11 and the second shock-absorbing part 10-12 is perpendicular to the axis of the spent fuel wet transportation container, that is, when the grain direction of the wood is consistent with the lateral impact direction, their shock resistance and structural stability can be maximized; the second shock-absorbing part 10-12, the fourth shock-absorbing part 10-14, and the fifth shock-absorbing part 10-15 are all used to bear the axial impact of the spent fuel wet transportation container. The grain directions of the second shock-absorbing part 10-12, the fourth shock-absorbing part 10-14, and the fifth shock-absorbing part 10-15 are all parallel to the axis of the spent fuel wet transportation container, that is, when the grain direction of the wood is consistent with the axial impact direction, their shock resistance and structural stability can be maximized; the third shock-absorbing part 10-13 and the sixth shock-absorbing part 10-16 are used to bear the corner impact of the spent fuel wet transportation container. The grain directions of the third shock-absorbing part 10-13 and the sixth shock-absorbing part 10-16 are set at an acute angle to the axis of the spent fuel wet transportation container, so that the grain directions of the third shock-absorbing part 10-13 and the sixth shock-absorbing part 10-16 face the corners of the spent fuel wet transportation container, that is, when the grain direction of the wood is consistent with the angular impact direction, their shock resistance and structural stability can be maximized. Thus, it is ensured that the shock absorber 10 can better exert the shock-absorbing effect and enhance the seismic performance of the spent fuel wet transportation container.

[0116] As can be seen from the foregoing, the second shock-absorbing part 10-12 has to bear both the lateral impact and the end impact. Therefore, the grain direction of the second shock-absorbing part 10-12 can be perpendicular to the axis of the spent fuel wet transportation container or parallel to the axis of the spent fuel wet transportation container.

[0117] Among them, in some embodiments, the first shock-absorbing part 10-11, the fourth shock-absorbing part 10-14, and the fifth shock-absorbing part 10-15 are made of Chinese fir, and the second shock-absorbing part 10-12, the third shock-absorbing part 10-13, and the sixth shock-absorbing part 10-16 are made of balsa wood.

[0118] In some other embodiments, the first shock-absorbing part 10-11 is made of mahogany, and the second shock-absorbing part 10-12, the third shock-absorbing part 10-13, the fourth shock-absorbing part 10-14, the fifth shock-absorbing part 10-15, and the sixth shock-absorbing part 10-16 are made of balsa wood.

[0119] In principle, the filling wood in different regions is selected according to the requirements that the end impact meets an acceleration of 40g - 50g and the lateral impact meets an acceleration of 50g - 60g, and the longitudinal direction of the wood is kept consistent with the main impact direction. A shock absorber with the best anti-impact performance in different directions of the comprehensive end, lateral and corner parts is formed by combining wood blocks of different materials and different wood grain directions.

[0120] Among them, the adjacent shock-absorbing parts can be adhesively fixed through an adhesive, and the connection is reliable.

[0121] Such as Figure 9 and Figure 11 As shown, the shock absorber 10 further includes a housing part 10-2 wrapped outside the main shock-absorbing part 10-1. The housing part 10-2 can be made of a metal material and plays a role in structural support. The material of the housing part 10-2 includes but is not limited to stainless steel, carbon steel, etc.

[0122] Such as Figure 9 and Figure 11 As shown, the shock absorber 10 further includes a sleeve 10-C connected between the outer ring part 10-A and the column part 10-B. The sleeve 10-C is used to pass through the threaded part when the shock absorber 10 is threadedly connected to the container body 2.

[0123] The spent fuel wet transportation container of the embodiment of the present application is applicable to both the spent fuel assemblies of CPR (China Pressurized Reactor) units and the spent fuel assemblies of EPR (European Pressurized Reactor) units.

[0124] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements and retouches can still be made, and these improvements and retouches should also be regarded as the protection scope of the present application.

Claims

1. A wet transportation container for spent fuel, characterized in that, The spent fuel wet transportation container includes a receiving cavity for accommodating spent fuel assemblies. A pressure cavity is provided inside the wall of the spent fuel wet transportation container. The interior of the pressure cavity contains a protective gas with a preset pressure. There is a partition wall portion between the pressure cavity and the receiving cavity. The spent fuel wet transportation container further includes a one-way pressure valve, which is provided on the partition wall portion and can be opened when the internal pressure of the receiving cavity is higher than the preset pressure to connect the receiving cavity and the pressure cavity.

2. The spent fuel wet transportation container according to claim 1, characterized in that, The spent fuel wet transportation container includes an inner cover. The pressure cavity is provided in the inner cover, and the wall portion of the inner cover located inside the pressure cavity forms the partition wall portion.

3. The spent fuel wet transportation container according to claim 1, wherein The value range of the preset pressure is: 0.1 bar - 1 bar.

4. The spent fuel wet transportation container according to any one of claims 1-3, characterized in that A neutron shielding layer is provided inside the wall of the peripheral wall of the spent fuel wet transportation container. The neutron shielding layer is an annular structure surrounding the receiving cavity; Alternatively, the neutron shielding layer includes a plurality of neutron shielding rods. The neutron shielding rods extend along the axial direction of the spent fuel wet transportation container. Some of the neutron shielding rods are distributed circumferentially along the spent fuel wet transportation container and enclose an inner shielding ring. Some of the neutron shielding rods are distributed circumferentially along the spent fuel wet transportation container to enclose an outer shielding ring. The inner shielding ring is located inside the outer shielding ring, and any one of the neutron shielding rods in the outer shielding ring is located between two adjacent neutron shielding rods in the inner shielding ring.

5. The spent fuel wet transportation container according to any one of claims 1-3, characterized in that Heat dissipation fins are provided on the outer side of the peripheral wall of the spent fuel wet transportation container.

6. The spent fuel wet transportation container according to claim 5, characterized in that, The heat dissipation fins extend along the axial direction of the spent fuel wet transportation container and are distributed circumferentially along the spent fuel wet transportation container; Alternatively, the heat dissipation fins extend along the circumferential direction of the spent fuel wet transportation container and are distributed axially along the spent fuel wet transportation container.

7. The spent fuel wet transportation container according to claim 1, characterized in that, The spent fuel wet transportation container includes: A container body, which is a hollow structure with one end open; An inner cover, connected to the open end of the container body, and the container body and the inner cover enclose the receiving cavity; An outer cover, connected to the open end of the container body and located outside the inner cover; The materials of the container body, the inner cover and the outer cover are forged steel.

8. The spent fuel wet transportation container according to any one of claims 1-3, characterized in that, The spent fuel wet transportation container includes: A hanging basket, provided inside the receiving cavity. The hanging basket includes fuel tubes, and the material of the fuel tubes is boron steel.

9. The spent fuel wet transportation container according to any one of claims 1-3, characterized in that, The spent fuel wet transportation container further includes shock absorbers at both axial ends. In the cross-section of the shock absorbers, the outer contour of the shock absorbers is circular or square.

10. The spent fuel wet transportation container according to any one of claims 1 to 3, characterized in that, The spent fuel wet transportation container further includes shock absorbers at both axial ends. The shock absorbers include a main shock-absorbing portion, and the material of the main shock-absorbing portion is honeycomb aluminum.

11. The spent fuel wet transportation container according to any one of claims 1-3, characterized in that, The spent fuel wet transportation container further includes shock absorbers at both axial ends. The shock absorbers include a main shock-absorbing portion, and the material of the main shock-absorbing portion is wood.

12. The spent fuel wet transportation container according to claim 11, wherein, The shock absorbers further include: An outer ring portion. The main shock-absorbing portion of the outer ring portion includes a first shock-absorbing portion, a second shock-absorbing portion and a third shock-absorbing portion sequentially connected along the axial direction; The column part is connected to the middle of the outer ring part. A cavity structure with an open inner end is formed between the column part and the outer ring part. The column part protrudes from the outer surface of the outer ring part. The main shock-absorbing part of the column part includes a fourth shock-absorbing part, a fifth shock-absorbing part, and a sixth shock-absorbing part that are connected in sequence along the axial direction; The axial dimensions of the first shock-absorbing part, the second shock-absorbing part, and the third shock-absorbing part gradually decrease. The wood grain direction of the first shock-absorbing part is perpendicular to the axial direction of the spent fuel wet transportation container; The wood grain directions of the fourth shock-absorbing part and the fifth shock-absorbing part are parallel to the axial direction of the spent fuel wet transportation container; The wood grain directions of the third shock-absorbing part and the sixth shock-absorbing part are arranged at an acute angle to the axial direction of the spent fuel wet transportation container; The wood grain direction of the second shock-absorbing part is perpendicular to the axial direction of the spent fuel wet transportation container, or the wood grain direction of the second shock-absorbing part is parallel to the axial direction of the spent fuel wet transportation container.

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