Cask and operational facility thereof

Abstract

To provide a cask capable of reducing construction costs for storage facilities while preventing damage to a lid due to external loads such as earthquakes during storage, and an operational facility thereof.SOLUTION: A cask 1 includes: a frame 2; a lid 3 placed on an upper face 2a of the frame 2, on which a basket 4 storing radioactive material R is installed; a cylindrical body portion 5 that has a bottom end opening 5c to which the lid portion 3 is attached, in which the lid portion 3 is attached with the bottom end opening 5c facing downward; and a fixing member 6 for fixing the body portion 5 to the frame 2. An underside 3c of the lid 3 is arranged to be flush with a rim 5e of the bottom end opening 5c or to protrude downward from the rim 5e towards the frame 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cask and its operating facilities. [Background technology]

[0002] Casks for storing radioactive materials that can be used for transporting or storing radioactive materials have been known. The cask includes a body with an opening at the top and a lid that closes the opening of the body. The radioactive material is placed into the body through the opening, and the lid is attached to the opening, sealing the material within the body. In this case, a storage method has been proposed in which the cask itself is submerged in a spent fuel pool in a reactor building, the spent fuel is stored in the cask underwater, and the cask is then transported from the spent fuel pool to the floor of the reactor building using a crane or other lifting device, and finally the lid is attached and sealed. The cask is then stored with the lid facing up, secured to the floor of the storage facility.

[0003] If an excessive load is applied to the cask during storage due to an earthquake or the like, the cask may tip over, causing the lid to collide with the floor or other equipment, potentially resulting in a large impact force being applied to the lid. Also, if the storage facility is damaged by an earthquake or the like, broken pieces or structures may become heavy objects and fall onto the cask, potentially resulting in a large impact force being applied to the lid. Generally, if a large impact force is applied to the lid, the damage to the lid may impair its sealing function, potentially resulting in the leakage of radioactive materials.

[0004] To address this issue, measures have traditionally been taken to firmly secure casks to the floor to prevent them from tipping over due to loads from earthquakes, etc. In addition, measures have been planned to ensure that the floor and ground have sufficient bearing capacity to prevent casks from tipping over, and that storage facilities are designed with sufficient earthquake resistance.

[0005] Meanwhile, a storage method using a buffer attached to the cask lid is also being considered. With this storage method, even if the cask were to tip over, the cask lid would not collide directly with the floor, preventing a large impact force from acting on the lid. This has the advantage that the floor of the storage facility does not need to have sufficient support to withstand the cask tipping over. In addition, because the lid is protected by the buffer, there is no need to design the storage facility with sufficient earthquake resistance to withstand the fall of heavy objects in the event of damage to the storage facility.

[0006] Additionally, a technique has been proposed in which a cask containing radioactive material is stored upside down with the lid facing downwards (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-291960 Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, measures such as firmly fixing the casks to the floor and designing the storage facility to have sufficient earthquake resistance would likely require large-scale design and construction, which would increase the construction costs of the storage facility.

[0009] Furthermore, the method of storing fuel by attaching buffers to the lids of casks requires preparing buffers with sufficient buffering capacity for all casks, which increases storage costs. In addition, the spacing between casks must be increased by the size of the buffers, which requires a large storage site, which increases construction costs.

[0010] Furthermore, in Patent Document 1, the cask containing the radioactive material must be turned upside down, which poses a risk of accidentally dropping the cask when changing its position.Furthermore, the radioactive material stored inside the cask may shift when the position is changed, and the resulting impact may damage the lid.

[0011] The present invention aims to solve the above-mentioned problems and provide a cask and its operating equipment that can prevent damage to the lid due to external loads such as earthquakes during storage and reduce the construction costs of storage facilities. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a cask comprising: a base, a lid placed on the top surface of the base and equipped with a basket for storing radioactive material, a cylindrical body having a bottom and a lower opening to which the lid is attached and to which the lid is attached with the lower opening facing downward, and a fixing member for fixing the body to the base. The lower surface of the lid is flush with the rim of the lower opening or protrudes downward beyond the rim toward the base.

[0013] The present invention also provides an operating facility for storing radioactive material in a cask, the operating facility including a pit formed in the floor of a building and in which the lid can be placed, and an elevator device for raising and lowering the lid within the pit, the body can be placed in the pit with the lower end opening corresponding to the floor opening, and the lid is raised within the pit by the elevator device and attached to the lower end opening through the floor opening. [Effects of the Invention]

[0014] The cask and its operating equipment according to the present invention can prevent damage to the lid due to external loads such as earthquakes during storage, and can reduce the construction costs of storage facilities. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a partially cross-sectional front view showing a cask according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a partially sectional front view showing another form of the cask according to the first embodiment. [Figure 3] FIG. 10 is a partial cross-sectional explanatory view showing the cask operating equipment according to the first embodiment. [Figure 4] FIG. 10 is a partial cross-sectional explanatory view showing how radioactive materials are stored in the basket of the cask according to the first embodiment. [Figure 5] This is also a partial cross-sectional explanatory diagram showing how radioactive material is stored in the body using the cask operation equipment related to the first embodiment. [Figure 6] FIG. 4 is a partial cross-sectional explanatory view showing the cask operation equipment according to the second embodiment of the present invention. [Figure 7] This is also a partial cross-sectional explanatory diagram showing how radioactive material is stored in the body of the cask using the cask operation equipment related to the second embodiment. [Figure 8] FIG. 4 is a partial cross-sectional front view showing a cask according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a partially sectional front view showing another form of the cask according to the third embodiment. [Figure 10] FIG. 10 is a partial cross-sectional front view showing a cask according to a fourth embodiment of the present invention. [Figure 11] FIG. 10 is a partial cross-sectional explanatory view showing the cask operating equipment according to the fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments, the same parts are designated by the same reference numerals, and redundant description will be omitted.

[0017] (First embodiment) As shown in Fig. 1, cask 1 is a container for storing, transporting, and storing radioactive material R. Cask 1 comprises a base 2, a lid 3, a body 5, and a fixing member 6. Cask 1 is configured such that body 5, sealed with lid 3, is fixed onto base 2 with lid 3 facing vertically downward.

[0018] The pedestal 2 functions as a base for the cask 1 and has a predetermined strength. The pedestal 2 is plate-shaped and is made of, for example, steel. The top surface 2a of the pedestal 2 is flat so that the lid 3 can be placed on it in a stable manner. The pedestal 2 is formed to be wider than the outer diameter of the body 5. This makes the cask 1 less likely to tip over.

[0019] The lid 3 is a member that seals the body 5. The lid 3 is attached by being pressed from below into the lower end opening 5c ​​of the body 5 via a gasket 3b using a fastening member such as a bolt (not shown). Note that, although one lid 3 is shown fixed to the lower end opening 5c, this is not limiting, and a structure using multiple lids may be used for purposes such as redundancy of the sealing function or monitoring of the sealing function. The dimensions of the lid portion 3 are adjusted so that, when attached to the lower end opening 5c, its lower surface 3c is flush with the lower end surface 5e of the tubular portion 5b, which forms the rim of the lower end opening 5c.

[0020] A basket 4 is mounted on the upper surface 3a of the lid portion 3. The basket 4 is a storage device for storing radioactive material R, and is fixed to the upper surface 3a of the lid portion 3 so as not to tip over. The basket 4 has a size (capacity) that allows it to be inserted into the interior space of the body portion 5. The basket 4 may have any shape as long as it can store the radioactive material R. Note that a basket plate (not shown) that can store the radioactive material R in a compartment may be provided inside the basket 4.

[0021] The body 5 has a cylindrical shape with a bottom that can store the radioactive material R (basket 4) inside. The body 5 has a bottom 5a, a cylindrical portion 5b that is continuous with the bottom 5a, and a bottom opening 5c ​​that is provided at the bottom end of the cylindrical portion 5b and to which the lid 3 is attached. The body 5 is positioned with the bottom 5a facing up and the bottom opening 5c ​​facing down both during storage and transportation of the cask 1. The lid 3 is attached to the bottom opening 5c ​​with the bottom opening 5c ​​facing downward.

[0022] The bottom 5a is formed with a vent hole 5d that communicates with the interior space of the body 5. The vent hole 5d releases gas generated from the radioactive material R to the outside of the cask 1. Note that the vent hole 5d is not necessarily provided and may be provided as needed. A plurality of trunnions 7 (two shown in FIG. 1) used for lifting and fixing are provided on the outer periphery of the lower part of the cylindrical portion 5b. Each trunnion 7 protrudes to the side of the cylindrical portion 5b.

[0023] The fixing member 6 is a member for fixing the body 5 (tubular portion 5b) to the pedestal 2 via a trunnion 7. The body 5 is fixed on the pedestal 2 by the fixing member 6 in an orientation in which the lower end opening 5c ​​faces downward.

[0024] When the body 5 is fixed on the pedestal 2, the underside 3c of the lid 3 comes into tight contact with the upper side 2a of the pedestal 2. That is, during normal storage, the weight of the lid 3 due to gravitational acceleration acting on the basket 4 and the radioactive material R stored therein acts vertically downward. Furthermore, during an earthquake, the load generated by the vertical acceleration caused by the earthquake acts vertically downward on the lid 3, superimposed on the weight. As a result, these vertically downward loads act as reaction forces from the pedestal 2 directly on the lid 3, resulting in the lid 3 being pressed against the lower end opening 5c ​​(body 5). This improves the sealing function of the lid 3B provided by the gasket 3b.

[0025] FIG. 2 is a partial cross-sectional front view showing another embodiment of the cask according to the first embodiment. As shown in Fig. 2, this cask 1A has a flange 8 at the lower end of the cylindrical portion 5b, and the barrel 5 is fixed to the pedestal 2 using fixing bolts 9 (fixing members) inserted into the flange 8. The number of fixing bolts 9 can be set as appropriate.

[0026] In this case as well, the dimensions of the lid portion 3 are adjusted so that its lower surface 3c is flush with the rim 8e of the flange portion 8 (the lower end surface of the tubular portion 5b) when attached to the lower end opening 5c.

[0027] In this cask 1A, when the body 5 is fixed on the pedestal 2, the lower surface 3c of the lid 3 comes into tight contact with the upper surface 2a of the pedestal 2. As a result, the vertically downward load acting on the lid 3 acts as a reaction force from the pedestal 2 directly on the lid 3, resulting in the lid 3 being pressed against the lower end opening 5c ​​(body 5). This improves the sealing function of the lid 3 by the gasket 3b.

[0028] Next, an operation facility 10 for storing radioactive material R in the cask 1 will be described with reference to Fig. 3. Fig. 3 is a partial cross-sectional explanatory view showing the operation facility for the cask according to the first embodiment.

[0029] The operational facility 10 comprises a pit P formed in the floor GL of a reinforced concrete structure of a building (not shown), and an elevator device 11 provided within the pit P. The pit P is large enough to accommodate the lid 3 and basket 4 of the cask 1, and has a capacity for temporarily storing the amount of radioactive material R that can be stored in one cask 1.

[0030] The lifting device 11 includes a lifting platform 12, ball screws 13, 13 for raising and lowering the lifting platform 12, and a drive mechanism 14 for driving the ball screws 13. The lifting platform 12 is configured to rise and fall within the pit P along the ball screws 13, 13 that are rotationally driven by the drive mechanism 14. The number of ball screws 13 can be set as appropriate. The lid 3, on which the basket 4 is mounted, is placed on the upper surface 12a of the lifting platform 12. A gasket 3b is fixed to the upper surface 3a of the lid 3. The lifting platform 12 is provided with a bolt tightening mechanism (not shown) for bolting the lid 3 to the lower end opening 5c ​​of the body 5. Such a lift platform 12 is usually kept on standby at the bottom surface P1 of the pit P. The drive mechanism 14 is disposed at the floor opening of the pit P, for example.

[0031] In such an operating facility 10, the body 5 of the cask 1 is placed on the floor opening of the pit P with its lower end opening 5c ​​facing the floor opening of the pit P, that is, with its lower end opening 5c ​​facing vertically downward. In this case, the lower end surface 5e of the cylindrical portion 5b of the body 5 is placed on the rim of the floor opening of the pit P, and the body 5 is installed on the floor opening of the pit P by aligning the lid 3 installed in the pit P so that it is in a position corresponding to the lower end opening 5c.

[0032] Here, when storing the radioactive material R in the basket 4 in the pit P, for example, as shown in FIG. 4 , the lifting platform 12 is raised by the lifting device 11 so that the top of the basket 4 is positioned at the floor opening of the pit P. This makes it easier to store the radioactive material R. The radioactive material R is temporarily stored in the pit P until an amount that can be stored in one cask 1 is accumulated in the basket 4. When the radioactive material R is temporarily stored in the pit P in an unsealed state, it is necessary to appropriately manage the compartments for radiation protection in consideration of radioactive contamination in the area around the pit P. Therefore, until the radioactive material R is accumulated in the basket 4, an appropriate lid structure or the like is provided at the floor opening of the pit P so that the inside of the pit P can be sealed.

[0033] Then, when the maximum amount of radioactive material R has accumulated in the basket 4, the trunk 5 is installed at the floor opening of the pit P using a lifting machine such as a crane (not shown), as described above. Then, as shown in FIG. 5, the lifting platform 12 is raised by the lifting device 11. This causes the basket 4 to enter the trunk 5 through the floor opening of the pit P. The lifting platform 12 is then further raised by the lifting device 11, thereby attaching the lid 3 to the lower opening 5c ​​of the trunk 5. Once the lid 3 has been attached to the lower opening 5c, the lid 3 is bolted to the lower opening 5c ​​using a bolt tightening mechanism (not shown). Alternatively, a hole or a notch may be provided in the lifting platform 12 so that an operator can access the lid 3 from below through the hole or the notch and manually operate the bolt tightening mechanism.

[0034] Thereafter, the body 5 with the lid 3 fixed thereto is lifted using a lifting machine such as a crane and placed on the stand 2 placed in a separate location, and the trunnion 7 is fixed using a fixing member 6. As a result, the lower surface 3c of the lid 3 abuts against the upper surface 2a of the stand 2, and the cask 1 is assembled with the body 5 sealed with the lid 3 fixed on the stand 2. The cask 1 can be fixed to the floor of the storage facility as appropriate. That is, either a method of storing the cask 1 by fixing the frame 2 to the floor of the storage facility, or a method of storing the cask 1 without fixing the frame 2 to the floor of the storage facility can be adopted.

[0035] In this operational facility 10, the basket 4 is shown mounted on the lid 3, but this is not limiting, and the basket 4 may be installed in another location without being mounted on the lid 3 from the beginning, and the radioactive material R may be stored in that location before being moved into the pit P and mounted on the lid 3. In this case, since the basket 4 contains the radioactive material R, it is advisable to provide a shield to sufficiently reduce the amount of radiation in the surrounding area when moving it from another location to the pit P.

[0036] According to the cask 1 of this embodiment described above, the lower surface 3c of the lid 3 abuts against the upper surface 2a of the pedestal 2, and the body 5 sealed by the lid 3 is fixed to the pedestal 2, so that the lid 3 is protected by the pedestal 2 and the body 5. As a result, even if the cask 1 were to tip over due to an external load such as an earthquake, there is no risk of the lid 3 colliding with the floor or other equipment, and damage to the lid 3 can be prevented. Furthermore, even if the storage facility is damaged by an earthquake or the like, and broken pieces or structures become heavy objects and fall onto the cask 1, damage to the lid 3 can be prevented. Therefore, a deterioration in the sealing function due to damage to the lid 3 can be prevented in advance. Furthermore, the possibility of radioactive materials leaking into the environment can be eliminated.

[0037] Furthermore, because damage to the lid 3 can be prevented, there is no need to design the floor of the storage facility to have sufficient support strength to withstand the tipping over of the cask 1. Also, there is no need to design the storage facility to have sufficient earthquake resistance to take into account the possibility of heavy objects falling if the storage facility is damaged. Therefore, the construction costs of the storage facility can be reduced.

[0038] Furthermore, the cask 1 is configured so that the lid 3 is attached to the lower opening 5c ​​with the body 5 positioned with the lower opening 5c ​​facing downward, so there is no need to change the position of the cask 1 containing the radioactive material R to an upside-down position, and there is no need to worry about the cask 1 falling or the lid 3 being damaged when the position is changed.

[0039] Furthermore, the weight of the basket 4 and the radioactive material R stored therein acts vertically downward on the lid 3 due to gravitational acceleration. During an earthquake, a load generated by vertical acceleration due to the earthquake acts vertically downward on the lid 3, superimposed on the weight of the basket 4 and the radioactive material R stored therein. These vertically downward loads act as reaction forces from the base 2, which act directly on the lid 3. This presses the lid 3 against the lower end opening 5c ​​(body 5), improving the sealing function of the lid 3 by the gasket 3b.

[0040] Furthermore, even if the generation rate or frequency of radioactive material R is low, the radioactive material R can be stored in the cask 1 once one cask 1's worth of radioactive material R has accumulated in the pit P. This allows the radioactive material R to be stored in a storage facility rationally using a large cask 1, regardless of the generation rate or frequency of the radioactive material R to be stored in the cask 1.

[0041] Furthermore, according to the operating equipment 10 of this embodiment, a pit P is formed on the floor GL of the building and a lifting device 11 is provided in the pit P, which is a simple configuration that makes it possible to easily assemble a cask 1 in which the lid portion 3 is attached from below to the lower end opening 5c ​​of the body portion 5. Therefore, damage to the lid portion 3 due to external loads such as earthquakes during storage can be prevented, and the construction costs of storage facilities can be reduced.

[0042] Furthermore, since the pit P is installed by forming a hole in the floor GL, even if radioactive material R falls during storage work, the area into which the radioactive material R scatters can be limited to within the pit P. Furthermore, since there is already shielding around the pit P, such as soil and the foundation of the storage facility, the radiation dose around the pit P and in the work area is sufficiently low, and there is no need to install new shielding. Therefore, the construction costs of the storage facility can be reduced.

[0043] (Second embodiment) Next, cask operation equipment according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a partial cross-sectional explanatory view showing the cask operation equipment according to the second embodiment. This embodiment differs from the first embodiment in that a transport vehicle 15 for transporting the trunk section 5 is provided.

[0044] As shown in FIG. 6, the transporting vehicle 15 can move on its own on the floor GL with the trunk 5 placed thereon. The transporting vehicle 15 is equipped with a drive mechanism 16 for driving running wheels (not shown). A through-hole 17 that passes through the transporting vehicle 15 in the vertical direction is formed in the center of the transporting vehicle 15. The through-hole 17 is large enough to allow the lid 3 to pass through, and allows the lid 3 placed on the lifting platform 12 to pass through when the lid 3 is attached to the lower end opening 5c ​​of the trunk 5.

[0045] A fixing member 6 for fixing the body 5 (tubular portion 5b) via a trunnion 7 is provided on the upper surface 15a of the transporting vehicle 15. The body 5 is fixed by the fixing member 6 so that it straddles the rim of the through-hole 17 with the lower end opening 5c ​​facing downward. Above the pit P, the floor opening of the pit P and the lower end opening 5c ​​of the body 5 are in communication via the through-hole 17. The body 5 is moved onto the transporting vehicle 15 using a lifting machine such as a crane (not shown).

[0046] In such an operational facility 10, when storing radioactive material R in the trunk 5, first, the transport vehicle 15 to which the trunk 5 is fixed is driven toward the pit P and stopped on the pit P so as to straddle the floor opening of the pit P. In this case, the transport vehicle 15 is positioned so that the through-hole 17 of the transport vehicle 15 is in a position corresponding to the floor opening, i.e., so that the center of the through-hole 17 is on the central axis (not shown) of the cask 1 and on a trajectory (not shown) that is passed by the centers of the lid 3 and the basket 4 when the transport vehicle 15 is raised or lowered by the lifting platform 12.

[0047] 7, the lifting device 11 raises the lifting platform 12. This allows the basket 4 to enter the body 5 through the floor opening of the pit P and the through-hole 17 of the transport cart 15, and then the lid 3 is attached to the lower end opening 5c ​​of the body 5. Thereafter, the lid 3 is bolted in place using a bolt tightening mechanism (not shown).

[0048] Thereafter, the transport vehicle 15 is driven to the location where the shell 5 will be placed on the pedestal 2, and the shell 5 is released from its attachment to the transport vehicle 15. Then, using a lifting machine such as a crane, the shell 5 with the lid 3 fixed thereto is lifted up and transferred onto the pedestal 2 and fixed thereto. As a result, the lower surface 3c of the lid 3 abuts against the upper surface 2a of the pedestal 2, and the cask 1 is assembled, with the shell 5 sealed with the lid 3 fixed on the pedestal 2.

[0049] The cask 1 and operating facility 10 of this embodiment described above provide the same effects as those of the first embodiment. In addition, in this embodiment, the barrel section 5 can be transported using the transport vehicle 15, so that the barrel section 5 can be smoothly installed on the pit P. This increases the degree of freedom in installing the barrel section 5 in the pit P and in setting the location where the barrel section 5 is placed on the cradle 2.

[0050] The transport vehicle 15 can be moved by various methods, such as by tires, by wheels mounted on rails, or by floating the vehicle by blowing compressed air from the underside of the transport vehicle 15. In this case, the most appropriate means is selected taking into consideration the restrictions of the temporary storage area where the radioactive material R is temporarily stored and the pit P.

[0051] (Third embodiment) Next, a cask according to a third embodiment will be described with reference to Fig. 8. Fig. 8 is a partial cross-sectional front view showing a cask according to the third embodiment. The cask 1B of this embodiment differs from the cask 1 of the first embodiment in that the lower surface 3c of the lid portion 3B protrudes toward the pedestal 2.

[0052] As shown in Fig. 8, the dimensions of the lid portion 3B are adjusted so that it is thicker than the lid portion 3 of the first embodiment (see Fig. 1). As a result, the lower surface 3c of the lid portion 3B is not flush with the lower end surface 5e (rim) of the lower end opening 5c, but protrudes downward, forming a step between it and the lower end surface 5e of the lower end opening 5c. Meanwhile, the lower end surface 5e of the lower end opening 5c ​​faces the upper surface 2a of the base 2, with a gap formed between it and the lower end surface 5e.

[0053] In the cask 1B of this embodiment, when the body 5 is fixed on the pedestal 2, the lower surface 3c of the lid 3B comes into tight contact with the upper surface 2a of the pedestal 2. As a result, the vertically downward load acting on the lid 3B acts as a reaction force from the pedestal 2 directly on the lid 3B, resulting in the lid 3B being pressed against the lower end opening 5c ​​(body 5). This improves the sealing function of the lid 3B provided by the gasket 3b.

[0054] FIG. 9 is a partial cross-sectional front view showing another form of the cask according to the third embodiment. As shown in Figure 9, this cask 1C, like the other forms described in the first embodiment, has a flange portion 8 at the lower end of the cylindrical portion 5b, and the body portion 5 is fixed to the frame 2 using a fixing bolt 9 inserted into the flange portion 8.

[0055] In the cask 1C of this embodiment, when the body 5 is fixed on the pedestal 2, the lower surface 3c of the lid 3B comes into tight contact with the upper surface 2a of the pedestal 2. As a result, the vertically downward load acting on the lid 3B acts as a reaction force from the pedestal 2 directly on the lid 3B, resulting in the lid 3B being pressed against the lower end opening 5c ​​(body 5). This improves the sealing function of the lid 3B provided by the gasket 3b.

[0056] (Fourth embodiment) Next, a cask according to a fourth embodiment will be described with reference to Fig. 10. Fig. 10 is a partial cross-sectional front view showing a cask according to the fourth embodiment. A cask 1D of this embodiment differs from the casks 1, 1A to 1D of the first to third embodiments in that the fitting of the lid portion 3D with the lower end opening 5c ​​is achieved by an abutting structure using tapered surfaces.

[0057] 10, the lower end opening 5c ​​has a tapered inner circumferential surface 5f that narrows in diameter from the opening end toward the inside of the body 5. Meanwhile, the lid portion 3D has a tapered outer circumferential surface 3e that corresponds to the inner circumferential surface 5f of the lower end opening 5c. The lid portion 3D is attached to the lower end opening 5c ​​by abutting the outer circumferential surface 3e of the lid portion 3D against the inner circumferential surface 5f of the lower end opening 5c.

[0058] According to this cask 1D, when the lid portion 3D is attached to the lower end opening 5c, the outer peripheral surface 3e of the lid portion 3D comes into contact with the inner peripheral surface 5f of the lower end opening 5c, thereby providing an alignment action, and the lid portion 3D is smoothly attached to the lower end opening 5c. Note that such an abutment structure using tapered surfaces is effective when it is not possible to set a large gap between the lower end opening 5c ​​and the lid portion 3D when they are fitted together.

[0059] (Fifth embodiment) Next, an operating facility according to the fifth embodiment will be described with reference to Fig. 11. Fig. 11 is a partial cross-sectional explanatory view showing the operating facility according to the fifth embodiment. The operation facility 10A of this embodiment differs from the operation facility 10 described above in that the lifting device 11 is provided with a position adjustment mechanism 18.

[0060] The position adjustment mechanism 18 is provided on the lifting platform 12 of the lifting device 11. The position adjustment mechanism 18 is a mechanism for adjusting the position of the lid 3 relative to the lower end opening 5c ​​of the body 5, and is capable of moving the lifting platform 12 horizontally relative to the ball screws 13. Between both sides of the lifting platform 12 and both inner surfaces of the pit P, movement spaces S1, S1 are formed to allow horizontal movement of the lifting platform 12. Note that a sensor (not shown) is provided within the pit P that can detect misalignment of the lid 3 relative to the lower end opening 5c ​​of the body 5.

[0061] According to this operating facility 10A, when the lid 3 is misaligned with respect to the bottom opening 5c ​​of the body 5, the position adjustment mechanism 18 can move the lifting platform 12 in the horizontal direction based on the value detected by the sensor, thereby eliminating the misalignment of the lid 3. This allows the lid 3 to be smoothly attached to the bottom opening 5c ​​of the body 5. Therefore, the time required for the storage operation of the radioactive material R can be shortened, and costs can be reduced.

[0062] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and each component can be appropriately modified within the scope of the invention. For example, the lifting device 11 is shown as using the ball screw 13, but is not limited to this, and may be configured to lift the lifting platform 12 by, for example, a hydraulic cylinder, a scissor lift, or the like.

[0063] Furthermore, although the configuration has been shown in which the lower surfaces 3c of the lid portions 3, 3B, and 3D directly contact the upper surface 2a of the stand 2, the present invention is not limited to this, and a member may be interposed between the lower surfaces 3c and the upper surface 2a so that they indirectly contact each other. In this case, the interposed member may be, for example, a disk-shaped member having the same diameter as the lid portions 3, 3B, and 3D or a member such as a shim, having a smaller diameter than the lid portions 3, 3B, and 3D.

[0064] Furthermore, an insertion recess for lifting may be formed on the underside of the pedestal 2. By forming such a recess in the pedestal 2, the casks 1, 1A to 1D can be lifted and moved by a lifting device or the like, improving the convenience of movement, etc. [Explanation of symbols]

[0065] 1, 1A-1D casks 2 Mounting stand 2a Top surface (mounting) 3, 3B, 3D lid part 3a Top surface (lid) 3e Outer surface (lid) 4 Basket 5. Torso 5c Bottom opening 5f Inner surface (bottom opening) 6 Fixing member 5e, 8e Lower end surface (rim) 10, 10A operating equipment 11 Lifting device 15 Transport cart 17 Through hole 18 Position adjustment mechanism GL floor P Pit R Radioactive material

Claims

1. A cask for storing radioactive material, A stand and a lid portion placed on the top surface of the stand and equipped with a basket for storing radioactive materials; a cylindrical body portion having a bottom and a lower end opening to which the lid portion is attached, the lid portion being attached in a state where the lower end opening is directed downward; a fixing member that fixes the trunk portion to the mount, A cask characterized in that the lower surface of the lid portion is flush with the rim of the lower end opening or protrudes downward beyond the rim toward the base.

2. the lower end opening has a tapered inner circumferential surface that narrows toward the inside of the body portion, 2. The cask according to claim 1, wherein the lid portion has a tapered outer peripheral surface that corresponds to the inner peripheral surface of the lower end opening.

3. An operation facility for storing radioactive materials in the cask according to claim 1 or 2, a pit formed on the floor of a building and in which the lid portion can be placed; a lifting device that lifts and lowers the lid portion in the pit, The pit is capable of disposing the trunk portion in a state in which the lower end opening corresponds to a floor opening of the pit, An operational facility characterized in that the lid portion is raised within the pit by the lifting device and attached to the lower end opening through the floor opening.

4. a transport vehicle that can move on the floor with the trunk portion placed thereon; The transport vehicle is movable onto the pit so as to straddle the floor opening, 4. The operation facility according to claim 3, wherein the transport vehicle has a through-hole through which the lid portion raised within the pit by the lifting device can pass.

5. The operation facility according to claim 3 , wherein the lifting device has a position adjustment mechanism that can adjust the position of the lid portion relative to the lower end opening.

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