JPH0760447A - Welding equipment under airtight condition - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide welding of pipes and rods, especially fuel rods filled with nuclear fuel pellets, easily, highly accurately and economically in an airtight state. [Structure] There is a support (3, 4) that rotatably and detachably supports a cladding (1) of a fuel rod and an end plug (2), and the cladding (1) is provided between the opposing mounts. ) And the end plug (2) are provided with an airtight chamber (17) that keeps the periphery of the welded part in a sealed state. Further, a magnetic fluid seal (15) is provided at the joint between the airtight chamber and the rotating part of the table (3, 4), while the covering pipe (1) of the table (3, 4) is provided.
The O-ring (25) and the member (3
2) is provided, and the O-rig (25) is crushed by the member and pressure-bonded to the outer peripheral surface of the cladding tube (1) to maintain an airtight state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for welding pipes and rods, particularly fuel rods filled with nuclear fuel pallets, in an airtight state.

[0002]

2. Description of the Related Art In a nuclear fuel rod, a cladding tube is filled with fuel pellets, and end plugs are welded at both ends of the cladding tube to seal the cladding. In this case, helium or argon is used to prevent welding failure. Welding under an atmosphere of an inert gas such as gas, the entire welding device is provided in a special large airtight chamber to form the atmosphere, and the air in the airtight chamber is replaced with the above inert gas. We are welding.

[0003]

Since the conventional welding apparatus is constructed such that the entire apparatus is covered with the airtight chamber as described above, the airtight chamber becomes large in size, and the inert gas sealed in the airtight chamber is removed. The consumption was high, the cost was high, and there were many problems in terms of maintenance. An object of the present invention is to solve the above-mentioned drawbacks and to provide a welding apparatus which is economical, easy to handle, and has high accuracy.

[0004]

SUMMARY OF THE INVENTION The present invention is designed to mainly cover the periphery of a welded part without covering the entire welding device in an airtight chamber. Further, in order to maintain the airtightness in the airtight chamber, a magnetic fluid seal and an O-ring are provided on a table for supporting a member involved in welding, and the O-ring is pressed to be crimped to the outer periphery of the member.

[0005]

1 to 3 show a case where a cladding tube (1) and an end plug (2) of a nuclear fuel rod are welded. The cladding tube (1) and the end plug (2) are the bases (3) and (4), respectively.
It is rotatably supported by and is detachable by chucks (5) and (6).

To open and close the chuck (5), an opening and closing screw (8) provided at the end of the spindle (7) is rotated, and the chuck is slid through a drawbar (9) screwed to the screw. It will be performed by guiding you inside the bu (10). After opening and closing, the lever (11) of the opening and closing screw (8) is hooked on the pawl (12) at the end of the spindle to prevent its rotation.

A housing (13) is provided on the outer circumference of the chuck (5) side end of the spindle (7), and a bearing (14) and a magnetic fluid seal (15) are mounted in the housing. .

An airtight chamber (17) is provided between the housing (13) and the housing (16) similarly formed on the chuck (6) side.
Is provided, when the cladding pipe (1) and the end plug (2) are welded, the air in the airtight chamber is discharged from the air supply / exhaust passage (18), and helium, argon gas, etc. are discharged into the airtight chamber. Inert gas is introduced.

At the time of welding, the stepped portion (19) of the end plug (2) is pushed (press-fitted) into the end portion of the cladding tube (1), and the gear (20) on the cladding tube side and the end are driven by a driving device (not shown). While rotating the fuel rods (1, 2) with a spindle (7) (end plug side spindle not shown) which is rotated synchronously via a gear on the plug side (not shown), the periphery of the joint (21) is rotated. Weld with the welder (22).

In the illustrated case, the spindle (7)
Is supported by the base (3) via a bearing (23), but the base and the housing (13) may be integrally formed, or the housing may be configured as a base.

The airtight chamber (17) is kept airtight as follows. Since the covering pipe shown in the drawing is formed in a hollow shape, a blind plug (24) is attached to the end of the pipe at the time of welding (it is not necessary when one end plug is already welded to the end).
The ferrofluid seal (15) is provided at a portion that is rotated relative to each other, such as between the spindle (7) and the housing (13).

An O-ring (25) is used for a portion supporting the cladding tube (1), and the O-ring is crushed and pressed against the outer periphery of the cladding tube to keep the portion airtight. In the illustrated example, a fixed block (26) fixed to a table (3) or a table provided separately on the end side of the cladding tube, and a support (27) and an oil seal (28) supported on the block. The rotary block (29) is provided, and the end block (30) is provided at the end of the rotary block. A hollow portion (31) is formed in the rotation block (29), and a sliding body (32) is inserted into the hollow portion (31) to form an annular protrusion of the sliding body.
(33) can enter and leave the annular hole (34) of the end block. An O-ring (25) is inserted in the annular hole (34), and the O-ring is crushed by the annular protrusion (33) of the sliding body which is pressed by the air sent from the sending path (35), The outer circumference of the cladding tube is crimped.

As shown in the drawing, the end face of the annular hole (34) and
The end surface of the annular protrusion (33) is formed in a groove with a mountain-shaped cross section, but if it is a shape sufficient to crush the O-ring, it should be formed in a rectangular, barrel-shaped, weight-shaped or other groove shape. You can

When returning the deformed O-ring to its original state,
The air pressure is released, and the slide body (32) is pushed back by the plunger (36) provided in the end block.

The support device on the end plug side is not provided with the blind plug (24) because the end plug is solid, and since the end plug is not supported in a penetrating state, the O-ring is not supported. There is also no mechanism for deforming.

Between the spindle (7) and the sleeve (10), between the sleeve (10) and the drawbar (9), the spindle (7)
Between the housing (13) and the housing (13), between the housing (13) and the airtight chamber (17) fixed by screws (40), between the airtight chamber (17) and the welder (22)
, The O-ring (37) and the rotary block (29), the rotary block (29) and the sliding body (32), and the like, respectively, in the non-rotating parts. (38), (39), (41), (4
2), (44), (45) are provided, and the airtightness is maintained between them.

[0017]

As described above, according to the present invention, since only the periphery of the welded portion is formed in an airtight state as described above, the entire apparatus can be made compact and the amount of inert gas used during welding can be reduced, which is economical. is there. Further, since a portion for supporting the member involved in welding is provided with a magnetic fluid seal and a means for deforming the O-ring to press it against the member, a sufficient airtight state can be maintained, and the O-ring is deformed. The member can be easily attached and detached by the means. Also, in a glove box that handles nuclear fuel substances, it can be generated by filling the glove box with an inert gas or by spraying an inert gas on the welding site to create an inert gas atmosphere at the welding site. According to the present invention, the change in the atmospheric pressure or the negative pressure in the glove box, which has a certain effect, does not affect the atmospheric pressure or the negative pressure in the glove box at all, and the atmospheric pressure or the negative pressure in the facility handling the nuclear material is maintained. Can contribute to management.

[Brief description of drawings]

FIG. 1 is a partially cutaway cross section showing an embodiment of the present invention.

FIG. 2 is a partially cutaway enlarged cross-sectional view showing a state before the O-ring is pressed and deformed.

FIG. 3 is a partially cutaway enlarged cross-sectional view showing a state where the O-ring is crushed and pressure-bonded around the cladding tube in FIG.

[Explanation of symbols]

 1 Cover pipe 2 End plugs 3, 4 units 13 Housing 15 Magnetic fluid seal 17 Airtight chamber 22 Welding machine 25 O-ring 29 Rotating block 32 Sliding body

Front page continued (72) Inventor Kenji Iwai 1250 Nishikosasa, Yokaichiba, Chiba Prefecture

Claims (2)

[Claims] 1. A support for supporting members to be welded in an opposed manner and a table for rotatably and detachably supporting the members, and a space for keeping a periphery of a welded portion of the member in a hermetically sealed state between the opposed supports. An airtight welding device with a closed chamber. 2. A magnetic fluid seal is provided at the joint between the airtight chamber and the rotating portion of the base, and an O-ring and a pusher are provided at the portion of the base that supports the member, and the O-ring is provided by the pusher. The welding apparatus under an airtight state according to claim 1, wherein the welding apparatus is deformed and pressure-bonded to the outer peripheral surface of the member to maintain an airtight state.