JP3794066B2 - Canister lid welding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a canister lid welding apparatus for welding a canister body and a canister lid for storing radioactive waste such as spent fuel.
[0002]
[Prior art]
When the fuel used in a nuclear reactor such as a nuclear power plant is used for about 3 to 4 years, fission products accumulate in the fuel, which limits combustion, and is therefore replaced with new fuel.
[0003]
Moreover, the spent fuel exchanged with the new fuel is stored in a state where it is immersed in water in a spent fuel storage pool provided in a nuclear power plant or the like.
[0004]
This spent fuel contains unburned uranium and plutonium produced by the combustion of the fuel in a state of being mixed in the fission products. Recently, the spent fuel has been recovered to recover unburned uranium from the spent fuel. It has been studied to recycle the uranium obtained as a fuel for nuclear reactors after processing.
[0005]
On the other hand, the spent fuel reprocessing operation has not been carried out in earnest at present, and is therefore stored in the spent fuel storage pool as described above.
[0006]
In view of this, it has been studied to seal the spent fuel in a storage container (canister) and store the canister in the air-cooled state until the decay heat of the spent fuel is removed in the radioactive waste storage facility.
[0007]
[Problems to be solved by the invention]
However, since spent fuel has a high radiation dose, the spent fuel is welded to the inner edge of the upper end opening of the canister cylinder containing the spent fuel and the outer peripheral edge of the canister lid fitted into the upper end of the canister cylinder. When encapsulating the canister, the operator cannot access the canister with the welding torch.
[0008]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a canister lid welding apparatus capable of welding a canister lid to a canister body while shielding radiation from radioactive waste.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, in the canister lid welding apparatus according to claim 1 of the present invention, a fixed portion that can be placed on the upper surface of the canister lid, and a virtual axis that passes vertically through the center of the fixed portion . A rotating part attached to be able to rotate coaxially, a welding torch attached to be able to move laterally to the rotating part, and attached to be able to move laterally to the rotating part A non-destructive inspection sensor and a shield attached to the rotating part so that the canister cylinder and the canister cover can be covered from above when the fixed part is placed on the upper surface of the canister cover fitted to the upper end of the canister cylinder. I have.
[0010]
In the canister lid welding apparatus according to claim 2 of the present invention, the fixing portion in the canister lid welding apparatus according to claim 1 of the present invention is formed of a gamma ray shielding material, and the shielding body is formed of a neutron shielding material. .
[0011]
In any of the canister lid welding apparatuses according to claim 1 and claim 2 of the present invention, the fixing portion of the canister lid welding apparatus is placed on the upper surface of the canister lid in a state where the canister lid is fitted into the upper end of the canister body. Then, the shield covers the canister cylinder and the canister lid from above, and shields radiation emitted upward from the inside of the canister cylinder.
[0012]
Further, by rotating the rotating portion with respect to the fixed portion and operating the welding device, the outer edge portion of the canister lid and the upper edge inner edge portion of the canister body are welded over the entire circumference.
[0013]
Further, the rotating portion is rotated with respect to the fixed portion and the nondestructive inspection sensor is operated to inspect the welded portion between the outer edge portion of the canister lid and the upper edge inner edge portion of the canister cylinder over the entire circumference.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
1 and 2 show an example of an embodiment of a canister lid welding apparatus according to the present invention. The canister lid welding apparatus is placed at the center of the upper surface of the canister lid 1 and is located with respect to the canister lid 1. A fixing part 2 that can be bolted, a rotating part 3 that is attached to the upper part of the fixing part 2 so as to be coaxially rotatable with respect to the fixing part 2, and that it can move horizontally to the rotating part 3 An attached welding torch (TIG welding torch) 4, a nondestructive inspection sensor (ultrasonic flaw detection probe) 5 attached to the rotating part 3 so as to move in the horizontal direction, and the rotating part 3 And a shield 6 attached to the upper surface of the.
[0016]
As shown in FIG. 3, the canister to be filled with spent fuel is fitted into a hollow canister cylinder 7 having a closed lower end and a circular opening at the upper end, and the upper end of the canister cylinder 7. And a disc-shaped canister lid 1 that can be formed.
[0017]
Further, the canister is accommodated in a cask which is a transport container.
[0018]
This cask is constituted by a hollow cask cylinder 20 having a closed lower end and a circular opening at the upper end, and a disk-shaped cask lid (not shown) that can be fitted into the upper end of the cask cylinder 20. .
[0019]
The fixing portion 2 of the canister lid welding apparatus is formed of carbon steel or the like that exhibits effective shielding against γ rays, and a spur gear 8 is coaxially fixed to the upper surface of the fixing portion 2.
[0020]
The rotating unit 3 includes a rotational force transmission mechanism 9 and a motor 10 for rotating the rotating unit 3 with respect to the fixed unit 2, and is provided on the fixed unit 2 on the output shaft of the rotational force transmission mechanism 9. A pinion 11 that meshes with the spur gear 8 is attached.
[0021]
The rotating portion 3 is provided with guide bars 13 and 14 that extend substantially horizontally outward in the radial direction of the fixed portion 2 and have a rack 12 on the lower surface.
[0022]
The welding torch 4 is attached to one guide bar 13 of the rotating portion 3 so as to move along the guide bar 13.
[0023]
The welding torch 4 includes a driving device 15 for moving the welding torch 4 along the guide bar 13. The driving device 15 meshes with the rack 12 of the guide bar 13. It has a pinion 16.
[0024]
The nondestructive inspection sensor 5 is attached to the other guide bar 14 of the rotating portion 3 so as to be movable along the guide bar 14.
[0025]
The non-destructive inspection sensor 5 includes a driving device 17 for moving the non-destructive inspection sensor 5 along the guide bar 14. The driving device 17 is a rack of the guide bar 14. 12 has a pinion 18 that meshes with 12.
[0026]
The shield 6 is formed of polyethylene or the like that exhibits effective shielding against neutron rays, and is placed coaxially on the upper surface of the rotating unit 3 so as to be positioned above the welding torch 4 and the nondestructive inspection sensor 5. And bolted to the rotating part 3.
[0027]
The shield 6 has a diameter that can cover the canister cylinder 7 and the canister cover 1 from above when the canister cover 1 is fitted to the upper end of the canister cylinder 7 and the fixing portion 2 is placed on the upper surface of the canister cover 1. Have.
[0028]
Reference numeral 19 denotes an eyebolt. The eyebolt 19 is attached to the center of the rotating portion 3 through the shield 6 in the vertical direction for lifting the canister lid welding device by a crane or the like (not shown). ing.
[0029]
Hereinafter, the operation of the canister lid welding apparatus shown in FIGS. 1 and 2 will be described.
[0030]
When the canister lid 1 is welded to the canister cylinder 7, the canister lid 1 is inserted into the upper end of the canister cylinder 7 inserted in the cask cylinder 20 (see FIG. 3) in advance, and then the crane is not shown. The canister lid welding device is lifted through the eyebolt 19, and the canister lid welding device is placed so that the fixing part 2 of the canister lid welding device abuts on the upper surface of the canister lid 1 and the centers of the canister lids 1 coincide with each other. The part 2 is bolted.
[0031]
Thereby, the shield 6 of the canister lid welding apparatus is inserted into the upper end portion of the cask cylinder 20 as shown by a two-dot chain line in FIG.
[0032]
Further, the canister body 7 and the canister cover 1 are covered from above by the shield 6 of the canister cover welding apparatus.
[0033]
Next, the driving device 15 of the welding torch 4 is operated, and the welding torch 4 is moved along the guide bar 13 via the pinion 16 that meshes with the rack 12, whereby the welding torch 4 is moved to the inner edge portion of the canister cylinder 7. And the outer edge of the canister lid 1.
[0034]
Further, when the welding of the canister body 7 and the canister lid 1 is completed, the driving device 17 of the nondestructive inspection sensor 5 is operated, and the nondestructive inspection sensor 5 is guided to the guide bar via the pinion 18 engaged with the rack 12. 14, the non-destructive inspection sensor 5 is positioned on the welded portion where the inner edge of the canister cylinder 7 and the outer edge of the canister lid 1 are fixed.
[0035]
In this state, the motor 10 of the rotating unit 3 is operated, and the pinion 11 is driven via the rotational force transmission mechanism 9, thereby operating the welding torch 4 while rotating the rotating unit 3 at a predetermined speed. Then, the inner edge part of the canister body 7 and the outer edge part of the canister lid 1 are fixed by welding.
[0036]
Further, by operating the motor 10 of the rotating unit 3, the nondestructive inspection sensor 5 is operated while rotating the rotating unit 3 at a predetermined speed, and the inner edge of the canister body 7 and the outer edge of the canister lid 1 are operated. The quality of the state of the welded part that adheres to the part is checked.
[0037]
As described above, in the canister lid welding apparatus shown in FIGS. 1 and 2, the fixing portion 2 made of carbon that exhibits shielding properties against γ rays and mountable on the upper surface of the canister lid 1, and the neutron beam The shield 6 is formed of polyethylene having a shielding property and can cover the canister cylinder 7 and the canister lid 1. Therefore, the radiation from the radioactive waste stored in the canister cylinder 7 is effectively shielded. be able to.
[0038]
Further, since the welding torch 4 and the non-destructive inspection sensor 5 for performing the welding between the canister cylinder 7 and the canister lid 1 and the inspection of the welded portion are arranged below the shielding body 6, While shielding the radiation emitted from the inserted radioactive waste, welding of the canister lid 1 to the canister body 7 and inspection of the welded portion can be easily performed.
[0039]
It should be noted that the canister lid welding apparatus of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.
[0040]
【The invention's effect】
As described above, according to the canister lid welding apparatus of the present invention, the following various excellent effects can be achieved.
[0041]
(1) In a state where the canister lid is fitted into the upper end of the canister cylinder, the canister cylinder and the canister lid are covered from above by the shield when the fixing portion of the canister lid welding device is placed on the upper surface of the canister lid. The radiation emitted upward from the radioactive waste stored inside the trunk can be effectively shielded.
[0042]
(2) Since the welding torch and the nondestructive inspection sensor are arranged below the shield, the canister cylinder and the canister lid are shielded while shielding the radiation emitted from the radioactive waste inserted into the canister cylinder. Inspection of welds and welds can be performed.
[0043]
(3) Since the shield, the welding torch, and the nondestructive inspection torch are attached to the rotating portion, the time required for the welding operation and the inspection operation for the welded portion can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a canister lid welding apparatus according to the present invention.
FIG. 2 is a plan view showing an example of an embodiment of a canister lid welding apparatus according to the present invention.
FIG. 3 is a conceptual diagram of a canister body and a canister lid related to FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Canister lid 2 Fixed part 3 Rotating part 4 Welding torch 5 Nondestructive inspection sensor 6 Shield 7 Canister body

Claims (2)

A fixed part that can be placed on the upper surface of the canister lid, a rotating part that is attached so as to be able to rotate coaxially with a virtual axis that passes vertically through the center of the fixed part, and moves laterally to the rotating part A welding torch attached so as to obtain, a nondestructive inspection sensor attached so as to move laterally to the rotating part, and a fixing part on the upper surface of the canister lid fitted into the upper end of the canister cylinder A canister lid welding apparatus comprising: a canister body and a shield attached to a rotating portion so that the canister body and the canister lid can be covered from above when placed. The canister lid welding apparatus according to claim 1, wherein the fixed portion is formed of a gamma ray shielding material, and the shielding body is formed of a neutron shielding material.

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