JPS6340317Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an automatic gas pressurized welding device for nuclear reactor fuel rods, the interior of which is pressurized and sealed with plenum gas.

Conventionally, nuclear reactors are loaded with fuel assemblies, and fuel rods are incorporated into the fuel assemblies. To manufacture this fuel rod, as shown in FIG. 1, a plurality of fuel pellets 2 are placed in a cladding tube 1,
A spring 3 is fitted to prevent the fuel pellets 2 from moving or being damaged, and then end plugs 4 and 5 are fitted into both ends of the cladding tube 1.
and cladding tube 1, and then inject plenum gas (for example, helium gas) 6 into cladding tube 1.
is filled under pressure from one end plug having the through hole 7, and the through hole 7 portion is melt-sealed.

Conventionally, a gas pressure welding device shown in FIG. 2 has been used as an example to seal the small through hole 7. In this welding device, first, a fuel rod is inserted a predetermined amount into a welding chamber 8 through an end plug 5 having a small through hole 7 first, and then the fuel rod is held by a fuel rod holder 9.

Next, plenum gas is introduced into the welding chamber 8 from the pipe 10 and the gas pressure in the chamber is increased to a predetermined pressure, and the electrode 11 is energized to open the through hole 7.
The parts are melt-sealed. This melt sealing (TIG welding) requires an arc (start) to ensure sufficient penetration.
The current is large, and therefore the electrodes are rapidly consumed. Depending on the shape of the electrodes after consumption, the arc start may be defective or the penetration position of the small through hole 7 may be deviated from the center. For this reason, it was necessary to frequently adjust the gap between the electrode and the welding part and replace the electrode.

In addition, a tungsten electrode rod with a high melting point is used for this welding, but if the distance between the end of the fuel rod and the electrode is too large, a large current will flow, which will melt the tungsten electrode rod and cause the end plug made of Zircaloy to melt. The problem arose that it got caught in the seal.

Furthermore, since the gap adjustment and electrode replacement have conventionally been performed manually, there has been a problem in that welding quality varies depending on the operator.

This idea was made in view of the above circumstances,
By providing an electrode positioning mechanism, an electrode exchange mechanism, etc., it is possible to prevent the tungsten electrode rod from melting and entering the welding area, and it is also possible to avoid arc start failures due to changes in the electrode shape. It is an object of the present invention to provide an automatic gas pressure welding device for nuclear reactor fuel rods, which can eliminate variations in welding quality between workers and further reduce costs through automation.

An embodiment of this invention will be described below with reference to FIGS. 3 to 5. Reference numeral 21 in FIG. 3 is a base, and a welding chamber main body 23 having a welding chamber 22 is fixedly attached to the upper surface of this base 21 via a connecting member 24.

Through holes 25 and 26 are formed in both left and right end walls in FIG. 3 of the welding chamber main body 23 so as to be located on the same axis parallel to the base 21.

A gasket receiver 27 provided in the welding chamber 22 is fitted into the through hole 25 and is airtightly attached. There is a gasket 28 inside the gasket receiver 27.
are fitted in a tightly fitted state, and the flange 29
A packing presser 30 having a sealing pad 30 is inserted in a loosely fitted manner so as to be movable. The flange 29 projects outside the welding chamber main body 23. A through hole for inserting a fuel rod 31 is formed at the center of each of the packing receiver 27, the packing 28, and the packing holder 30.

A pressing mechanism 32 is provided on the left side of the packing presser 30 in FIG. 3. This pressing mechanism 32
is a bracket provided on the base 21 (not shown)
a shaft 33 attached to the shaft 33; a lever 34 rotatably attached to the shaft 33;
The base 21 is rotatably attached to one end of the base 21.
The cylinder mechanism 35 is rotatably attached to a bracket (not shown) provided in the cylinder mechanism 35. A through hole into which the fuel rod 31 can be loosely inserted is formed at the other end of the lever 34 .

A chuck mechanism 36 is provided on the left side of the pressing mechanism 32 in FIG. 3, slightly spaced apart from the pressing mechanism 32, and is attached to the base 21 by suitable means not shown. And the packing receiver 2
7, the packing 28, the packing presser 30, the pressing mechanism 32, and the chuck mechanism 36 constitute a holding mechanism that holds the fuel rod 31 in the welding chamber main body 23 in a tightly fitted state.

Further, on the left side of the chuck mechanism 36 in FIG.
8 are provided vertically and spaced apart from each other. The fuel rod 31 can be inserted between the fuel rod feed roller 37 and the fuel rod press roller 38, and the fuel rod 31 can be freely moved in the directions of arrows A and B in FIG. 3 by rotation of the fuel rod feed roller 37. ing.

Furthermore, a window 39 and a light source 40 are provided on the upper and lower walls of the welding chamber main body 23, respectively, and are located on the same vertical line. The window 39 has a transparent window glass 41
is installed.

A linear image sensor 42 is provided above the window 39. This linear image sensor 42
is supported by a bracket 43 provided on the base 21.

On the right side of the welding chamber main body 23 in FIG.
4 is fixedly provided on the base 21. stand 44
A torch body 45 is provided on the top in a slidable and insulated manner. The torch body 45 is attached to the base 2
Connecting rod 4 of cylinder mechanism 46 attached to 1
This cylinder mechanism 46 is insulated and connected to
Therefore, it is movable in the directions of arrows A and B in FIG.

A through hole 48 is formed in the center of the torch body 45, and a sleeve (electrode holding portion) 49 is slidably fitted into the through hole 48 with a slight right end remaining. This sleeve 49 is the torch main body 45
It protrudes slightly from the end surface on the welding chamber main body 23 side.
An insulating plate 50 is fitted into this protruding portion and attached to the torch body 45. A hole 51 is formed in the peripheral wall of the sleeve 49, as shown in FIG. Further, a leaf spring 52 is attached to the side wall of the sleeve 49.
is buried. The leaf spring 52 passes through the hole 51 and projects into the inner hole 53 of the sleeve 49 under pressure. Further, a female threaded portion is formed at the right end portion of the sleeve 49 in FIG. Further, a notch 54 is formed at the upper right end of the sleeve 49 in the same figure.

Further, a pulse motor 55 is slidably provided on the table 44. An adjusting screw 56 is connected to the rotating shaft 55a of the pulse motor 55 via an insulating joint. The adjustment screw 56 is screwed into a female threaded portion of the sleeve 49.

Further, a stepped hole 57 is formed in the torch body 45 , and a pin 58 is fitted into the stepped hole 57 , and this pin 58 is fitted into the notch 54 .
The tip of the pin 58 does not reach the adjustment screw 56.

On the other hand, an electrode stock mechanism 61 is provided in the vicinity of the torch body 45 and supported by a column 62 provided on the base 21 .

In the electrode stock mechanism 61, a large number of electrodes (tungsten electrodes) 63 are detachably attached to one side of a disk at predetermined intervals in the circumferential direction, and these electrodes 63 are rotatably held together with the disk. It is what was done.

Further, an electrode exchange mechanism 64 is provided opposite the electrode stock mechanism 61. As shown in FIGS. 3 and 5, this electrode exchange mechanism 64 includes a cylinder mechanism 65 connected to the base 21, and an arm 66 rotatably attached to a piston rod 65a of the cylinder mechanism 65. , this arm 6
6 and a chuck 67 provided at the tip. The chuck 67 has holding claws 67a, 67b,
It consists of a cylinder mechanism 68 connected to holding claws 67a and 67b. The piston rod 65a of the cylinder mechanism 65 can move forward and backward into and out of the cylinder of the cylinder mechanism 65, and can also rotate.

The linear image sensor 42 is located directly above the window 39 and accurately measures the distance between the tip of the fuel rod 31 inserted into the welding chamber main body 23 and the tip of the electrode 63 through the window 39. It is made so that it can be measured.

Further, a pipe 69 for introducing plenum gas into the welding chamber 22 is airtightly provided on the upper wall of the welding chamber main body 23.

Next, the operation of the welding apparatus configured as described above will be explained.

(1) A large number of electrodes 63 whose tips are ground and formed are set in the electrode stock mechanism 61.

(2) Insert the fuel rod 31 whose through hole formed in the end plug is to be melt-sealed between the fuel rod press roller 38 and the fuel rod feed roller 37 with the through hole first, and The feed roller 37 is rotated in the direction of arrow C in FIG. Then, fuel rod 31
The tip of the end plug side passes through the open chuck mechanism 36, passes through the through holes of the lever 34, the packing holder 30, the packing 28, and the packing receiver 27, and enters the welding chamber 22 at a predetermined position.

(3) Next, the cylinder mechanism 35 operates and its piston rod advances from the cylinder, and the lever 34
rotates and presses the seal presser 30 in the direction of arrow B in FIG. Then, the packing presser 30 crushes the packing 28, so that the packing 28 maintains the airtightness of the left end wall of the welding chamber 22 in FIG.

(4) Next, the chuck mechanism 36 operates and the fuel rod 3
Hold 1.

(5) Next, the cylinder mechanism 46 operates and the connecting rod 4
7, the torch body 45 is moved in the direction of arrow B in FIG. At this time, the pulse motor 55 also moves in the same direction together with the torch body 45.

(6) Next, with the electrode exchanging mechanism 64 separated from the electrode 63 of the electrode stocking mechanism 61, the electrode stocking mechanism 61 rotates so that the new electrode 63 faces the chuck 67.

(7) Next, the cylinder mechanism 68 is activated to open the chuck 67, and then the cylinder mechanism 65 is activated to move the arm 66 toward the electrode stock mechanism 61, positioning the electrode 63 between the holding claws 67a and 67b. Then, the cylinder mechanism 68 operates to close the holding claws 67a, 67b, and the holding claws 67a, 67
The electrode 63 is held between b.

(8) Next, the cylinder mechanism 65 operates and the arm 6
6 moves away from the electrode stock mechanism 61. Then, the electrode 63 is pulled out from the electrode storage mechanism 61 while being held by the chuck 67.

(9) Next, the cylinder mechanism 65 operates and the arm 6
6 is rotated by 90 degrees to a horizontal state, and the electrode 63 is positioned between the welding chamber main body 23 and the insulating plate 50 of the torch main body 45.

(10) Next, the cylinder mechanism 65 operates and the arm 6
6 moves toward the torch body 45 side. Then, the electrode 63 held by the chuck 67 is attached to the sleeve 4.
9, stops at a predetermined position, and removes the sleeve 4.
It is set to 9. At this time, the recess 63a of the electrode 63 reaches the tip of the leaf spring 52 shown in FIG.
Since the electrode 63 is engaged with and pressed against the sleeve 49, the electrode 63 is prevented from coming off from the sleeve 49.

(11) Next, the cylinder mechanism 68 is activated to open the chuck 67, releasing the electrode 63 set in the sleeve 49, and then the cylinder mechanism 65 is activated to move the arm 66 in the direction of arrow A in FIG. After that, rotate it 90 degrees and stand it upright.

(12) Next, the cylinder mechanism 46 operates and the connecting rod 4
7, the torch body 45 moves in the direction of arrow A in FIG. Then, the electrode 63 set in the sleeve 49 fits into the welding chamber 22, and
The tip of the electrode 63 faces the tip of the fuel rod 31 in the welding chamber 22, and the electrode 63 stops at a position slightly separated from the tip. Further, at this time, the insulating plate 50 comes into pressure contact with the end wall of the welding chamber main body 23 and closes the through hole 26 portion.

(13) Next, plenum gas (helium gas) is fed into the welding chamber 22 from the pipe 69, and the fuel rod 3
The inside of the cladding tube 31a of the fuel rod 31 is pressurized and filled with helium gas at a specified pressure (approximately 30 atmospheres) through the small through hole formed in the end plug 1.

(14) Next, with the light source 40 turned on, the linear image sensor 42 measures the distance between the tip of the electrode 63 and the tip of the fuel rod 31, and the pulse motor 55 is operated to adjust the movement of the electrode 63 in the direction of arrow A or B in FIG. Here, when the pulse motor 55 is operated, the adjustment screw 56 rotates together with its rotating shaft 55a. Then, since the sleeve 49 is screwed onto this adjustment screw 56 and the pin 58 is fitted into the notch 54 of this sleeve 49, the sleeve 49 cannot rotate.
It moves in the direction of arrow A or B in FIG. Since the electrode 63 is set in the sleeve 49, this electrode 63 also moves together with the sleeve 49, and the distance between the tip of the fuel rod 31 and the tip of the electrode 63 is adjusted.

(15) Next, while the fuel rods and the welding chamber 22 are pressurized with plenum gas, the electrode 63 is energized by an energizing means (not shown). As a result, the electrode 63
As a result, an arc is generated, and the small through hole of the end plug of the fuel rod 31 is melt-sealed.

(16) When the small through hole is melt-sealed, the plenum gas pressurization is released from the piping 69 and the cylinder mechanism 3
5 is activated, and the lever 34 presses the seal presser 3.
The pressure of 0 is released. As a result, fuel rod 3
1 is released, the chuck mechanism 36 opens, and the fuel rod feed roller 37 rotates in the direction of arrow D in FIG. 3 to move the fuel rod 31 in the direction of arrow A in FIG. 3. Welding chamber main body 23, pressing mechanism 32,
The fuel rods are taken out from between the chuck mechanism 36, the fuel rod holding roller 38, and the fuel rod feeding roller 37.

(17) Next, the operations (2), (3), and (4) above are performed.

(18) Next, the operations (13) and (15) above are performed.

(19) Next, the operations (16) to (18) above are repeated.

(20) When the small through hole is melt-sealed, the electrode 63 is consumed due to the flow of a large current, and when the arc cannot be started with the current within the specified range, the cylinder mechanism 46 is automatically operated and the torch body is connected via the connecting rod 47. 45 moves in the direction of arrow B in FIG. As a result, the electrode 63 is removed from the welding chamber main body 23, and the torch main body 45 stops.

(21) Next, the cylinder mechanism 65 of the electrode exchange mechanism 64, which stands upright with the chuck 67 open, is actuated, and the arm 66 rotates 90 degrees to become horizontal. Next, the cylinder mechanism 65 is actuated to move the arm 66 in the direction of arrow B in FIG.
A chuck 67 is fitted into the used electrode 63. Then, the cylinder mechanism 68 is actuated, the chuck 67 closes, and the used electrode 63 is gripped.

(22) Next, the cylinder mechanism 65 is activated and the arm 66 moves in the direction of arrow A in FIG.
As a result, the used electrode 63 is removed from the sleeve 49.
is extracted.

(23) Next, the cylinder mechanism 65 rotates, and the arm 66 rotates 90 degrees and stands upright. Then, the electrode stock mechanism 61 rotates so that its electrode insertion cavity faces the used electrode 63 held by the chuck 67, and the electrode stock mechanism 61 stops rotating.

(24) Next, the cylinder mechanism 65 is activated, and the arm 66 moves in the direction of arrow B in FIG.
As a result, the used electrode 63 is inserted into the cavity of the electrode storage mechanism 61 and held there.

(25) Next, the cylinder mechanism 68 is activated to open the chuck 67, and then the cylinder mechanism 65 is activated, and the arm 66 moves in the direction of arrow A in FIG. 3 and stops at a predetermined position.

(26) On the other hand, after the sealing of the through hole is completed, the electrode 63
is removed from the welding chamber main body 23 ((16) above)
When activated) The cylinder mechanism 35 operates and the lever 3
The pressure on the packing presser 30 by 4 is released. As a result, the packing 28 to the fuel rod 31
is also released, the chuck mechanism 36 opens, and the fuel rod feed roller 37 rotates in the direction of arrow D in FIG.
is moved in the direction of arrow A in FIG.
6. Take out the fuel rods outward from between the fuel rod holding roller 38 and the fuel rod feeding roller 37.

(27) Thereafter, the operations (1) to (26) above are repeated to automatically fill the fuel rod 31 with helium gas and melt-seal the through hole of the end plug.
Further, when the electrode 63 is worn down to the point where arc starting is no longer possible, the electrode 63 is automatically replaced.

Note that each of the above operations is automatically performed by an automatic control device (not shown) attached to the apparatus of this embodiment.

As explained above, according to this invention, a fuel rod is inserted into a predetermined position in the welding chamber main body, and an electrode that is removably supplied to the torch main body, which can be moved into and out of the welding chamber main body, is inserted into the welding chamber main body. The fuel rod is inserted into the main body facing the tip of the fuel rod, plenum gas is supplied to the welding chamber, and the distance between the tip of the fuel rod and the electrode is adjusted to reduce the penetration of the end plug of the fuel rod. Since the hole is melt-sealed and the consumable electrode is replaced at the limit of its use, the distance between the tip of the fuel rod and the tip of the electrode is constant, which prevents melted electrode material from entering the welding area. It is also possible to avoid arc start failures caused by changes in the electrode shape, and it can be automated, which eliminates variations in welding quality due to workers, and saves labor and costs. can be reduced.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view showing an example of a fuel rod, Figure 2 is a schematic side sectional view of a conventional gas pressure welding device, and Figure 3 is a schematic side sectional view of a conventional gas pressure welding device.
The figure is a schematic side sectional view showing an embodiment of this invention, FIG. 4 is a sectional view of the main part thereof, and FIG. 5 is a perspective view thereof. 21... Base, 22... Welding chamber, 23... Welding chamber main body, 27... Packing holder, 28... Packing holder, 30... Packing holder, 31... Fuel rod, 3
2... Pressing mechanism, 35, 46, 65, 68... Cylinder mechanism, 36... Chack mechanism, 37... Fuel rod feeding roller, 38... Fuel rod pressing roller, 4
2... Linear image sensor, 45... Torch body, 49... Sleeve (electrode holding part), 61...
Electrode storage mechanism, 63...electrode, 64...electrode exchange mechanism, 66...arm, 69...piping.

Claims (1)

[Scope of utility model registration request] A welding device that pressurizes and fills a plenum gas into a fuel rod cladding tube and then melts and seals an inlet for the plenum gas, which includes a base, a welding chamber main body that has a welding chamber and is provided on the base, and the welding device. a holding mechanism provided in a chamber body to hold a fuel rod inserted into the welding chamber body in a tightly fitted state with the welding chamber body; and an electrode holding portion provided adjacent to the welding chamber body; a torch body that can be moved into and out of contact with the welding chamber body and that removably holds a supplied electrode on the same axis as the fuel rod; an electrode storage mechanism provided near the torch body;
It has an electrode holding mechanism, is provided so as to be able to move forward and backward with respect to the electrode stocking mechanism, and is rotatable around a predetermined fulcrum, takes out and holds the electrode from the electrode stocking mechanism, and supplies this electrode to the torch main body. and a linear image sensor that is provided in the welding chamber main body and detects the distance between one end of the fuel rod and the tip of the electrode inserted into the welding chamber opposite to this one end. An automatic gas pressure welding device for nuclear reactor fuel rods, which is characterized by: