JPS6262319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cask bagging device.

When spent nuclear fuel used in a nuclear reactor or the like is subsequently transferred to a reprocessing plant, a special transport container called a cask is used to prevent environmental exposure. The operation of storing spent nuclear fuel in casks is carried out in a fuel pool to ensure radioactivity protection, but at this time the outer surface of the cask becomes contaminated with pool water. Therefore, it is necessary to decontaminate it after work. However, decontamination work is extremely troublesome due to the shape of the cask, etc., and it is a good idea to omit this work as much as possible. Therefore, when dipping the cask into the pool water,
Attempts have been made to prevent staining by placing only the fuel insertion port in a watertight container and immersing it in pool water.

In other words, in the past, for example, Japanese Patent Application Laid-Open No. 54-148999
As seen in the publication, a bottomed box body is provided in the fuel pool that is guided so as to be raised and lowered via a guide body, and a lid body is connected to a trunnion integrated with the cask via a wire or a hanging ring. The cask is inserted into a box with a bottom by lifting it with a crane and suspending it. After that, the engaging piece on the lid side is engaged with the engaging claw on the bottomed box side to integrate the two, and then the lifting force by the crane is released. The bottom box body is sinking.

According to such a conventional method, during lifting or hanging, the lid is likely to swing relative to the crane body, and the cask is also likely to swing relative to the lid due to wires or the like.
Therefore, in the lifting path between the crane and the cask, there are two structures that are susceptible to swinging in their respective free directions, making it difficult to control the posture of the cask during lifting or hanging. Furthermore, since the bottomed box body is freely movable in the vertical direction, the lid cannot be stably fixed to or released from the bottomed box body.

An object of the present invention is to provide a cask bagging device that can easily control the posture of a cask during lifting or hanging, and can stably fix and release the fixation between a bottomed tank and a lid. .

In order to achieve the above object, the cask bagging device of the present invention includes a bottomed tank that can freely accommodate a cask through an opening formed on the top surface, and a lid body that can close the opening of the bottomed tank in a watertight state, The cask is formed by a cask body and a removable opening/closing lid on the top side of the cask body,
The lid body includes a mantle part that can freely accommodate a cask trunnion provided on the upper outer periphery of the cask body, a fitting part that hangs from the mantle side and can be inserted into and removed from the opening, and an inward part from the top of the mantle part. and a flange formed with a through hole in the center that allows the passage of the opening/closing lid, and a part of the mantle facing the cask trunnion that is inserted into and removed from the cask trunnion from the axial direction thereof. A flexible external trunnion insertion hole is provided, and the external trunnion inserted into the insertion hole is provided between the external trunnion and the mantle, between the bottomed tank opening and the insertion part, and between the upper surface of the cask body and the outer trunnion. A sealing material is provided to make the space between the flange and the lower surface watertight, and the bottomed tank is further supported on the base plate via a cylinder device for raising and lowering.

According to this structure of the present invention, the lid body is fitted into the upper part of the cask body through its outer part, and after aligning the insertion hole with respect to the cask trunnion, the external trunnion is inserted into the insertion hole and the cask trunnion is inserted. By fitting externally, the lid body and the cask are integrated (fixed) via this external trunnion. Therefore, lifting or hanging using a crane or the like can be performed via the external trunnion. Furthermore, since the bottomed tank is fixed in the raised position by the cylinder device, the lid is fixed and unfixed to a stable bottomed tank.

An embodiment of the present invention will be described below based on the drawings.

1 is a cask bagging device, 2 is a cask that can be freely accommodated in the cask bagging device 1, 3 is a hanging tool, 4
is a wire with a hanging tool 3 fixed to its lower end and suspended from a crane or the like (not shown). The cask 2 consists of a main body 5 and an opening/closing lid 6 that is attached to and removed from a fuel insertion hole (not shown in the figure) formed on the upper surface side of the main body 5. Fins 7 are provided at equal pitches over the entire height, and a pair of left and right cask trunnions 8 are provided laterally projecting from the upper outer periphery of the fins.
The cask trunnion 8 has a collar 9 at its tip. On the other hand, the cask bagging device 1 includes a bottomed tank 10 with an open top and a lid 12 that is attached to and removed from an opening 11 of the bottomed tank 10. The bottomed tank 10 is a rigid body reinforced by a plurality of ring stiffeners 13 on the upper and lower sides provided on its inner periphery, and has a plurality of brackets 14, 1 on its upper outer periphery.
It has 4. Reference numeral 15 designates a fairly heavy base plate, and cylinder devices 16, 16 for lifting and lowering are installed upright at multiple locations on the outer periphery of this base plate 15, and the ends of the rods are connected to the brackets 14, 14 through metal fittings 17, 17. Concatenated. The lid body 12 includes an annular flange portion 19 whose outer peripheral portion contacts the opening edge of the bottomed tank 10 via an inclined surface 18, and a ring-shaped flange portion 19 that protrudes downward from the lower portion of the outer edge of the flange portion 19 and contacts the opening edge of the bottomed tank 10. Insertion part 2 that can be freely inserted into and removed from 11
0 and erected from the center (upper inner edge) of the flange portion 19 and whose inner diameter is connected to the collar 9 of the cask trunnion 8.
A mantle portion 21 formed to be larger than the distance between the end faces of the
It is comprised of a flange part 28 that extends inwardly from the top of the mantle part 21 and has a through hole 37 formed in the center through which the opening/closing lid 6 passes. The mantle part 21 is
It is configured in a cylindrical shape having an inner diameter large enough to accommodate the cask trunnion 8 provided on the upper outer periphery of the large-diameter cask body 5 inside, and in a portion of the outer mantle 21 facing the cask trunnion 8, An insertion hole 23 is bored into which a separately provided external trunnion 22 can be inserted and removed. The external trunnion 22
The shaft portion 25 has a fitting hole 24 for the cask trunnion 8 with the inner end open, and the outer end of the shaft portion 25 has a collar 26. The fitting hole 24 has a diameter large enough to receive the collar 9 of the cask trunnion 8 without a gap, and is split into two to ensure that both trunnions 8 and 22 are fitted. A cylindrical spacer 38 is configured to be detachable from the ring of the cask trunnion 8. In the lid body 12, annular grooves are formed on the outer surface of the fitting portion 20, the inner surface of the external trunnion insertion hole 23, and the lower surface of the flange portion 28 facing the upper surface 27 of the cask body 5, and a sealing material 29 is formed in these annular grooves. , 30, 31 are retained. Seal material 2
For 9, 30, and 31, generally known O-rings may be used, but preferably tube-shaped elastic inflates that expand and contract by air supply and exhaust are used. Note that 32 is a fuel pool, and 33 is a water surface of the pool. It has a shallow bottom part 35 for carrying out a watertight test of the seal part.

Attachment and detachment of the cask 2 and the lid body 12 are performed outside the fuel pool 32. That is, after the spacer 38 in the form of a split cylinder is attached to the ring part of the cask trunnion 8, the lid body 12 is fitted into the upper part of the cask body 5 via the outer mantle part 21 thereof. At this time, the opening/closing lid 6 projects outward through the through hole 37, and the lower surface of the flange 28 comes into contact with the upper surface 27 of the cask body 5. Then, the insertion hole 23 is aligned with the cask trunnion 8, and then the external trunnion 22 is fitted onto the cask trunnion 8 through the insertion hole 23.
When O-rings are used as the sealing materials 30 and 31, this operation completes the attachment of the lid 12 to the upper part of the cask body 5, ensuring a watertight state of the seal portion. In this case, although there are various types of cask 2 (diameter and length of the main body), by making the shape of both cask trunnions 8 and the distance between the end faces of both collars 9 the same, it is possible to make any type of cask 2. A common lid body 12 can be attached even if the lid body 12 is used. Note that when inflates are used as the sealing materials 30 and 31, the inside of the inflates are evacuated to contract before the lid body 12 is attached, and air is supplied to the insides of the inflates after the attachment by the external trunnion 22 is completed. This is expanded and sealed. After the lid 12 is attached to the cask 2 in this manner, the hanging tool 3 is locked to the external trunnion 22 and then lifted to lower the cask 2 into the bottomed tank 10. In this case, the bottomed tank 10 has a cylinder device 16 in an extended state on a base plate 15 placed on the shallow bottom 35 of the fuel pool 32.
As a result, the opening 11 is on standby in a state projected above the pool water surface 33, and the cask 2 is suspended through this opening 11. By suspending the cask 2, the fitting portion 20 of the lid body 12 is easily fitted into the opening 11. Next, after fixing the bottomed tank 10 and the lid 12, the same operation as described above is performed on the sealing material 29 to apply a watertight seal to this part. This state is shown by the imaginary line X in FIG. Next, move on to the watertight test of the seal part. That is, in the watertight test, the cylinder device 16 is retracted and the seal portion is submerged in water as shown by the imaginary line Y in FIG. 1 and the solid line in FIG. protrude upwards,
This is to check for water intrusion. In this case, since both the cask 2 and its bagging device 1 are hollow, they will not completely collapse unless pushed in by a forced external force. Therefore, the base plate 15 and the cylinder device 16 are necessary to solve this problem. After confirming that the seal is secure, the cask bagging device 1 is moved to the deep bottom part 34 by a crane as shown by the solid line Z in FIG. 1, and the spent nuclear fuel storage operation begins.

According to the present invention having the above configuration, the lid body is fitted into the upper part of the cask through the outer part thereof, and after aligning the insertion hole with the cask trunnion, the external trunnion is passed through the insertion hole and inserted into the cask trunnion. By fitting externally, the lid body and cask can be integrated (fixed) via this external trunnion, and lifting and hanging using a crane etc. can be performed via the external trunnion. . Therefore, when lifting or suspending, you only need to be careful of the shaking that is likely to occur between the crane, etc. and the external trunnion, and the posture of the cask can be easily controlled, and the position of the cask relative to the bottomed tank can be easily controlled. can be inserted and removed safely. In addition, the bottomed tank is
Since the cylinder device allows the lid to be fixed in the raised position, the lid can be safely and reliably fixed and unfixed to a bottomed tank that is in a stable position. Furthermore, the external trunnion fixes the cask and the lid, and by adjusting the amount of insertion thereof, it is possible to provide a lid that is compatible with casks of different diameters.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, with FIG. 1 being a side view of the device in use, and FIG. 2 being a longitudinal sectional view. 1... Cask bagging device, 2... Cask, 5
...Main body, 6.Opening/closing lid, 8.Cast trunnion,
10...bottomed tank, 11...opening, 12...lid, 1
5... Base plate, 16... Cylinder device, 20... Fitting part, 21... Mantle part, 22... External trunnion, 23
... External trunnion insertion hole, 24 ... Cask trunnion insertion hole, 27 ... Cask main body upper surface, 28 ... Flange section, 29, 30, 31 ... Seal material, 32 ... Fuel pool, 33 ... Pool water surface, 37 ... Through hole.

Claims (1)

[Claims] 1. The cask has a bottomed tank that can freely accommodate a cask through an opening formed on the top surface, and a lid body that can close the opening of the bottomed tank in a watertight state, and the cask has a cask body and an upper surface of this cask body. A cask trunnion is formed on the side of the cask body and a cask trunnion is provided on the outer periphery of the upper part of the cask body. a fitting part, and a flange part which is connected inward from the top of the mantle part and has a through hole formed in the center through which the opening/closing lid passes, and in a part of the mantle part facing the cask trunnion. , the cask trunnion is provided with an insertion hole for an external trunnion that can be freely inserted and removed from the axial direction thereof, and between the external trunnion fitted in the insertion hole and the mantle, and between the opening of the bottomed tank and the insertion hole. A sealing material is provided to make watertight between the cask body and the upper surface of the cask body and the lower surface of the flange portion, and the bottomed tank is further supported on a base plate via a cylinder device for lifting and lowering. A cask bagging device featuring: