JP2593174B2 - Filter fitting extraction device used for end plug welding device of nuclear fuel rod - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of the Invention The present invention relates to an apparatus for extracting a filter fitting used in an end plug welding apparatus for a nuclear fuel rod.

B. Prior Art A nuclear fuel rod used in a nuclear reactor is composed of a plurality of nuclear fuel rod elements 10 shown in FIG. Each element 10 has a cladding tube 12 of zirconium alloy or stainless steel plugged at one end with an end plug 11, in which the required number of pellets 13
After inserting a spring 14, the inside of the tube is replaced with an inert gas, and the other end of the cladding tube 12 is sealed with an end plug 15 to press and place the pellet 13 at the tube end with a spring force. You. Generally, the end plug 15 is welded to the pipe end by TIG (tungsten inert gas welding) welding or laser welding (see, for example,
-113198 or JP-B-53-38396).

In welding the end plug 15, a step of inserting one end of the cladding tube 12 into which the filter fitting is lightly press-fitted into the welding chamber and pulling out the filter fitting first is essential. Therefore, in the conventional drawing device, a gripper for holding the filter fitting is inserted and arranged in the welding chamber, and a mechanism for moving the gripper forward and backward and opening and closing is installed outside the chamber. Sealing.

C. Problems to be Solved by the Invention In the case of manufacturing a fuel rod element in which a high-pressure (for example, 30 atm) inert gas is sealed inside the nuclear fuel rod element 10, the inside of the welding chamber is pressurized to, for example, about 30 atm. End plug welding is performed. For this reason, in the conventional filter fitting removing device using a telescopic bellows, a large thrust load acts via the telescopic bellows, and the mounting mechanism must be strengthened. Another problem is that the gripping force of the gripper is insufficient in the conventional device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a filter fitting extracting device for use in a nuclear fuel rod end plug welding device which solves such a problem.

D. Means for Solving the Problems The filter fitting removal device according to the present invention is a filter fitting removal device that pulls out the filter fitting lightly pressed into the tip of the cladding tube having one end inserted into the chamber, A pair of gripping members for gripping the filter fitting, one end is inserted into the chamber, and a gripping member is attached to a tip thereof, and the other end is extended and retracted shaft extending outside the chamber. Reciprocating axis driving means installed outside the chamber for driving and reciprocating the gripping member with respect to the cladding tube entrance path, and the gripping member is provided coaxially with the advancing and retreating shaft, and at the tip inserted into the chamber. A control member that opens and closes by a wedge action is provided, and the other end extends outside the chamber, and the holding member is driven by the control member by driving the open / close axis in the axial direction. An opening / closing shaft driving means installed outside the chamber to be closed and driven; a swing bearing provided in the chamber for swingably supporting the advance / retreat shaft and the opening / closing shaft; and an opening / closing shaft provided outside the chamber. And swing means for swinging the opening / closing shaft about the swing bearing, and sealing means for individually sealing gaps communicating between the inside and outside of the chamber between these respective components. Solve the problem.

E. Action Advance the reciprocating shaft into the chamber and position the filter bracket between the gripping members. By driving the opening / closing shaft, the filter member is firmly gripped by the gripping member by the wedge action of the control member and the gripping member. The holding member is rocked by the rocking means, and the filter fitting is pulled out. The reciprocating shaft and the opening / closing shaft are coaxially provided through the swing bearing, and the respective gaps are individually sealed by sealing means such as O-rings to maintain the airtightness in the chamber. Since a conventional bellows having a large pressure receiving area does not collectively maintain the airtightness, a thrust load acting on the extracting device can be reduced.

F. Embodiment An embodiment will be described with reference to FIGS. The same parts as those in FIG. 4 are denoted by the same reference numerals.

The end plug welding device in which the filter fitting removal device according to the present invention is implemented includes, for example, a main chamber 10 into which the end of the cladding tube 12 is inserted for welding the end plug 15 in helium gas.
The main chamber 100 is provided with the following devices (1) to (8).

(1) Welding machine 110: As shown in FIG.
The laser beam emitted from the laser head 111 through the quartz window 101 attached to the main chamber 100 is composed of a laser head 111 and a laser power supply / control unit 112.
Then, the end plug 15 is circumferentially welded. The laser head 111 is controlled by a laser power supply / control unit 112.

(2) Filter fitting removing device 130: A device for removing the filter fitting 16 (FIG. 3) temporarily fixed to the tip of the cladding tube 12. This filter fitting removal device 130
As shown in FIGS. 1 to 3, a gripper driving device which is swingably supported by a spherical seat 102 attached to the main chamber 100 and moves forward and backward and opens and closes a tip gripper 131 inserted into the chamber 100. 130, the drive unit 130 is swung, and the filter fitting 16 gripped by the gripper 131 is placed in the cladding tube 1.
And a rocking device 150 that is withdrawn from 2.

The swing device 150 includes a pneumatic cylinder 151 whose base end is supported by a bracket 103 attached to the main chamber 100,
The output rod 152 includes a lever 153 having one end connected to the output rod 152 and the other end connected to the driving device 130, respectively.

The driving device 130 is a sectional view taken along a line II in FIG.
As shown in the figure, the device has a swing bearing 132 for swingably holding the entire device, and is screwed to the main chamber 100 while being pinched by a pair of fixed cracks 133A and 133B of a half-split type. . The outer cylinder 134a of the pneumatic cylinder 134 is fitted and supported on the swing bearing 132. A piston 134 of the pneumatic cylinder 134 is provided in the outer cylinder 134a.
Hollow output shaft 1 connected to c via snap ring 134d
34b is inserted, the tip of which is inserted into the main chamber 100, where the gripper 131 is attached. Gripper 131
Has a pair of gripping members 131A and 131B,
A pair of control plates 135A and 135B connected by pins 136 are slidably provided on the inclined outer surfaces of A and 131B. The pair of gripping members 131A and 131B are urged by a spring 144 in a release direction.

On the other hand, one end of the opening / closing drive shaft 137 penetrating through the hollow output shaft 134b extends into the main chamber 100, and a pin 136 is provided at the end thereof to hold the control plates 135A and 135B, and the other end is connected to the main chamber 100.
Externally, it is screwed to the output shaft 138a of the pneumatic cylinder 138. The pneumatic cylinder 138 is integrally connected to the hollow output shaft 134b by a holding frame 139.

The airtightness inside and outside the chamber when the drive device 130 is mounted on the main chamber 100 is maintained as follows.

An O-ring 140 is provided between the swing bearing 132 and the main chamber 100.
O-rings 141A and 141B are provided between the swing bearing 132 and the outer cylinder 134a.
An O-ring 142A, 1 is provided between the outer cylinder 134a and the hollow output shaft 134b.
At 42B, the space between the hollow output shaft 134b and the opening / closing drive shaft 137 is individually sealed by O-rings 143A and 143B, respectively.

(3) Filter fitting discharging device 160: The filter fitting discharging device 160 discharges the filter fitting 16 extracted by the filter fitting removing device 130 to the outside of the main chamber 100, and is attached to a lower portion of the main chamber 100. As shown in FIG. 3, the discharge device 160 includes a cylinder 161 that receives the extracted filter fitting 16, and a pneumatic cylinder 163 that moves the cylinder 161 to the discharge port 162. The filter fitting 16 is discharged.

(4) Cooling and twisting device 170: This is the main chamber 100
Is provided coaxially in the inside, and rotatably supports the tip of the inserted cladding tube 12, and cools the welded portion. That is,
As shown in FIG. 3, the collet chuck 172 is clamped by the clamping holder 171 rotatably supported in the main chamber 100 to hold the cladding tube 12. The collet chuck 172 is tightened by rotating the drill chucks 173a and 173b by a driver (not shown). The collet chuck 172 has a cooling capacity to function as a chill when the end plug 15 is circumferentially welded to the tip of the cladding tube 12.

(5) Positioning device 190: As shown in FIG. 3, a positioning member 191 which is attached to the lower part of the main chamber 100 and moves back and forth in a direction orthogonal to the insertion direction of the cladding tube 12, and a pneumatic cylinder 192 for driving the same. The positioning member 191 is advanced to the insertion path of the cladding tube 12 and the tip of the cladding tube 12 is brought into contact with the positioning member 191 to perform positioning at the time of welding.

(6) Supply device 200: A device that is attached to the right end of the main chamber 100, inserts the spring 14 into the cladding tube 12 inserted into the main chamber 100, and press-fits the end plug 15 into the end of the cladding tube 12. .

(7) Rotary seal device 300: attached to the left end of main chamber 100, inserts cladding tube 12 into main chamber 100, seals between cladding tube 12 that rotates during welding and main chamber 100, and vacuums. Main chamber 10 that varies from to 30 bar
Seal inside 0 securely. Therefore, as shown in FIG. 3, a Wilson seal 301, a mechanical seal 302, and a molded seal 303 are provided in this order from the inside of the chamber. The Wilson seal 301 and the mechanical seal 302
Is disposed on the outer periphery of the sealing cylinder 304 to be coaxially inserted, seals between the outer peripheral surface of the sealing cylinder 304 and the main chamber 100, and the molded seal 303 is formed of the sealing cylinder 304. It is held by a holding tube 305 provided at the left end, and seals the space between the outer peripheral surface of the cladding tube 12 and the sealing tube 304. A gear 305 is attached to the left end of the sealing cylinder 304. As shown in FIG. 2, a rotating force is transmitted from a motor 450 constituting the holding / rotating device 400 via a timing gear 453 and a timing belt 454, It is rotated in synchronization with the cladding tube 12. Molded seal 303
Is pressed by a pressing device 320 to ensure the sealing performance. The pressing device 302 includes a pneumatic cylinder 321 attached to the main chamber 100, a cylinder rod 322 thereof, a lever 323 having one end connected to the cylinder rod 322,
And a pressing member 324 for pressing the molded seal 303 by the lever 323.

(8) Further, as shown in FIG. 2, the welding apparatus includes a gripping / rotating device 400 for gripping and rotating the cladding tube 12 and a vacuum / evacuation device for evacuating the interior of the main chamber 100 and the supply device 200.
Helium gas pressurizing device that pressurizes and seals helium gas inside the exhaust device 500 and the main chamber 100 and the supply device 200
With 600.

With the above configuration, the end plug 15 is welded to the cladding tube 12 as follows.

Now, in the previous step, the pellet 13 is filled in the cladding tube 12 one end of which is closed by the end plug 11, and the other end of the cladding tube 12 is sealed with the filter fitting 16 (FIG. 3). And Such a cladding tube 12 is processed as follows.

First, the pneumatic cylinder 321 of the pressing device 320 is contracted, and the pressing member 324 is moved to the left in the drawing to loosen the molded seal 303. Is inserted into the main chamber 100 only on the filter fitting side. At this time, the tip of the cladding tube 12 does not reach the filter fitting removing device 170 as shown in FIG. 3, but is supported in a state where it slightly protrudes from the sealing cylinder 304 of the rotary sealing device 300.

Main chamber 100 and supply device 20 by vacuum / evacuation device 500
The inside of 0 is evacuated.

Thereafter, the main chamber 100 is replaced with a low-pressure helium gas higher than the atmospheric pressure by the helium gas pressurizing device 600.

Filter bracket 16 with filter bracket removal device 130
After the welding, the extracted filter fitting is discharged out of the main chamber 100 by the filter fitting discharging device 160.

That is, first, the opening / closing drive shaft 137 is driven by the pneumatic cylinder 138.
Is contracted to move the control plates 135A and 135B above the position shown in FIG. 1, and the springs 144 fully open the gripping members 131A and 131B. Next, the piston 134c of the pneumatic cylinder 134 is driven to the position shown in FIG. 1 to extend the output shaft 134b. At this time, the opening / closing drive shaft 137 is also driven together with the pneumatic cylinder 138, and the gripper 131 advances to the entrance passage of the cladding tube 12, and the filter fitting 16 is located between the gripping members 131A and 131B.

When the opening / closing drive shaft 137 is extended by the pneumatic cylinder 138, the gripping members 131A, 131B are formed by the wedge action of the control plates 135A, 135B.
Is closed, and the filter fitting 1 is held between the two gripping members 131A and 131B.
6 is gripped strongly. Next, the output shaft 152 is expanded and contracted by the pneumatic cylinder 151 to swing the lever 153 alternately in the clockwise and counterclockwise directions. This allows the extraction device 130
The whole swings about the swing bearing 132 as shown by the arrow A in FIG. 3, and the filter bracket 16 can be removed.

The cladding tube 12 is positioned by contacting the positioning member 191 of the positioning device 190. At this time, the tip of the cladding tube 12 penetrates the tightening holder 171 and the collet chuck 172 and contacts the positioning member 191. After positioning, collet chuck 1
Grab the tip of the cladding tube with 72.

After the positioning, the molded seal 303 is pressed by the pressing device 320,
The sealing property between the cladding tube 12 and the sealing cylinder 304 is enhanced.

The spring 14 is inserted into the cladding tube 12 by the supply device 200.

The supply device 200 first press-fits the end plug 15 into the other end of the cladding tube 12.

After that, the main chamber 1 is
The inside of 00 is pressurized with helium gas to, for example, about 30 atm. At this time, the inside of the cladding tube 12 is also replaced with helium gas at 30 atm. In this state, after the inside of the cladding tube is stabilized at a required pressure, the upper end plug is finally press-fitted.

Cladding tube by motor 450 constituting gripping and rotating device 400
The end plug 15 is circumferentially welded to the cladding tube 12 by the welding machine 110 while rotating the 12. At this time, the tip of the cladding tube 12 is
As a result, the cladding tube 12 is securely tightened, and the swinging caused by the rotation of the cladding tube 12 is prevented. Further, the collet chuck 172 has a sufficient cooling capacity as a chill, is transmitted from the cladding tube 12 during welding, and the penetration depth is substantially uniform over the entire circumference.

Discharge helium gas in the main chamber 100 at 30 atm,
The cladding tube 12 is withdrawn from the main chamber 100, and all operations are completed.

Thus, a nuclear fuel rod element 10 filled with helium gas at 30 atm is manufactured.

G. Effects of the Invention Since the present invention is configured as described above, an excessive thrust load does not act on the filter fitting extracting device due to the high pressure in the chamber, and it is necessary to strengthen the mounting mechanism as in the conventional example. Absent. Further, since the gripping member is closed by the wedge action, the gripping force is improved as compared with the related art.

[Brief description of the drawings]

1 to 4 illustrate one embodiment of the present invention.
FIG. 1 is a cross-sectional view taken along line II of FIG. 3 showing details of a filter fitting removing device according to the present invention. FIG. 2 is an overall schematic configuration diagram of a welding device provided with the filter fitting removing device according to the present invention. FIG. 3 is a front sectional view of the entire welding apparatus, and FIG.
The figure is a sectional view of the nuclear fuel rod element. 12: cladding tube, 13: pellet, 14: spring, 15: upper end plug 100: main chamber, 110: welding device 130: filter fitting removal device 131: gripper 131A, 131B: gripping member 132: swing bearing, 134: empty Pressure cylinder 134a: Outer cylinder, 134b: Hollow output shaft 134c: Piston 135A, 135B: Control plate 137: Opening / closing drive shaft, 138: Pneumatic cylinder 139: Holding frame 140, 141, 142, 143: O-ring 150: Oscillating device 160: Filter fitting discharge Device 190: Positioning device, 200: Parts supply device 300: Rotary seal device 400: Holding / rotating device 500: Vacuum / exhaust device 600: Helium gas pressurizing device

Claims (1)

(57) [Claims] An apparatus for removing a filter fitting lightly press-fitted into a distal end portion of a cladding tube having one end inserted into a chamber, comprising: a pair of holding members for holding the filter fitting; And a gripping member attached to the tip thereof, the other end of which extends out of the chamber; and an axially driving shaft that moves the gripping member forward and backward with respect to the cladding tube approach path. An advancing / retreating shaft driving means installed outside the chamber to be provided, a control member provided coaxially with the advancing / retreating shaft, and a control member for opening and closing the gripping member by a wedge action at a tip inserted into the chamber, and the other end is provided. An opening / closing shaft extending outside the chamber, an opening / closing shaft driving means installed outside the chamber for driving the opening / closing shaft in the axial direction and driving the holding member to open / close by the control member; A swing bearing provided in the chamber for swingably supporting the shaft and the opening / closing shaft, and swinging means provided outside the chamber and swinging the advance / retreat shaft and the opening / closing shaft about the swing bearing. And a sealing means for individually sealing gaps communicating between the inside and outside of the chamber between these constituent elements, respectively.