JPS63196895A - End plug welder for nuclear-reactor fuel rod - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an end plug welding device for nuclear reactor fuel rods, and in particular,
The present invention relates to a reactor fuel rod end plug welding device suitable for use in a pressure tube nuclear reactor.

[Conventional technology]

Conventional nuclear reactor fuel rod end plug welding equipment uses UO to the cladding tube.
Immediately after filling with Z pellets, the plenum spring is inserted manually or by an automated device, and then the upper end plug is inserted and rotated synchronously to weld the end plug. That is, the fuel element is prepared as described in Japanese Utility Model Application Publication No. 56-17599 or Japanese Patent Publication No. 58-28033,
The end plug is fed into the chamber mouth of the end plug welding device, the chamber is evacuated, and then the end plug is inserted into the fuel element, which has been replaced with helium gas at a predetermined helium pressure by replacing the inside of the chamber with helium gas, and while rotating. The upper end plug is welded.

[Problem that the invention seeks to solve]

However, fuel elements containing highly radioactive fuel require special attention to prevent radiation exposure, and the handling is significantly different from that of UOz pellets, and full automation of welding is desired. For example, a fuel element containing highly radioactive fuel is evacuated with a temporary end stopper attached to prevent the evacuation device from being contaminated with radioactive materials when the chamber is evacuated.
After removing the temporary end plug, it is necessary to automatically insert the plenum spring, evacuate with a specified helium gas, and weld the upper end plug. Moreover, the diameter of the upper plenum spring to be handled is small at around 10 m11, and the free length is long at over 200 am. Therefore, when handling the spring and inserting the cladding tube, the tip of the spring sag, making it difficult to position and insert it automatically. It is difficult to do this, and the current situation is that this is done manually in a box that can be contained, such as a glove box. In other words, after installing the cladding containing pellets of nuclear material into the chamber of the end plug welding device, inserting a plenum spring into the cladding, replacing the inside of the fuel element with helium gas, and then Set the end plug and seal it by welding around the end plug. However, it is not possible to insert the upper plenum spring and the upper end plug into the end opening of the cladding tube from the side opposite to the cladding tube insertion side of the chamber as they are, that is, by using a hand such as a robot without using an intervening member or the like. It is difficult. In addition, it took a long time to insert the fuel rod into one position, making it unsuitable for mass production of fuel rods.

An object of the present invention is to provide a nuclear reactor fuel rod end plug welding device that can significantly reduce the number of work steps and radiation exposure.

[Means for solving problems]

In the nuclear reactor fuel rod end plug welding device of the present invention, a lower end plug is sealed at one end of a fuel cladding tube, the inside is filled with helium gas, a plurality of pellets are stacked and filled from the bottom, and the other end plug is sealed with helium gas. After inserting the upper plenum spring into the end, the upper end plug is driven to rotate in a chamber with a helium gas atmosphere inside, and is driven to rotate integrally with the cladding tube whose inside is filled with helium gas. The sealed part is welded and fixed using a welding device, the upper end plug and the upper plenum spring are built into the cylindrical dummy, and the cylindrical dummy is placed in a concentric position with respect to the cladding tube which is held with its upper end located in the chamber. a storage column having a cylindrical dummy removably attached thereto and formed to be close to and separated from the cladding tube and rotatable integrally with the cladding tube; and a storage column shaft. a pusher which is slidably installed in a center position and is formed to insert an upper plenum spring in a cylindrical dummy into the cladding tube and to maintain a press-contact state when the upper end plug is welded to the cladding tube; means; a storage column;
A control device is provided to control the operations of the pusher and the welding device so that they are automatically performed in conjunction with each other.

[Effect]

The device of the present invention can be easily positioned and installed by simply setting the upper plenum spring and upper end plug in a dummy cylinder and inserting it into the storage column, and is facilitated by the pusher that loosely fits into the shaft center of the storage column.

The upper plenum spring and upper end plug can be quickly and automatically inserted into the cladding tube and set.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The end plug welding apparatus for nuclear reactor fuel rods according to the present invention will be described below with reference to FIGS. 1 to 3 using embodiments. This end plug welding device is used as a manufacturing device for reactor fuel rods used in pressure tube nuclear reactors.

Figure 1 is an explanatory diagram of the end plug welding device, Figure 2 is a cross-sectional view of the fuel element welded by the device in Figure 1, and Figure 3 is the opening/closing mechanism opened by the chamber opening/closing mechanism of the device in Figure 1. It is an explanatory view of a state where a dummy cylinder is inserted in the state. In the figure, 1 is an upper end plug, 2 is an upper plenum spring, 3 is a pellet, 4 is a lower plenum spring, 5 is a lower end plug, 6 is a cladding tube, 7 is a chamber, 8 is a torch, 9 is a pusher, and 10 is a The pusher gas supply port 11 is a pusher spring. Further, 12 is a chamber opening/closing table, 13 is a cylindrical dummy, 14 is a bearing, 15 is a storage column, 16 is an umbrella-shaped seal, 17 is a spring, 18 is an inert gas supply port, 1
9 is a ball screw, 20a and 20b are bearing frames, 2
1 is a gear, 22 is a base, 23 is a coupling, and 24 is a motor.

The lower end plug 5 and the cladding tube 6 are usually welded before the nuclear material pellets 3 are inserted, so there is generally no problem with radiation exposure or handling. The welding work for inserting the upper plenum spring 2 and the upper end plug 1 after they have been inserted into the housing and sealing the end plugs will be described.

First, the configuration of the end plug welding apparatus of this embodiment is roughly divided into a cylindrical dummy (first jig) 13, which attaches the upper end plug 1 and upper plenum spring 2 to the storage column 15, and a cylindrical dummy (first jig) Storage column that holds dummy 13 (
a second jig) 15, a pusher 9 that pushes the upper plenum spring 2 into the cladding tube 6 and presses the upper end plug 1, a welding device that welds the cladding tube 6 and the upper end plug 1 with a torch 8 in the chamber 7, etc. As shown in FIG. 4, the cylindrical dummy 13 includes an upper end plug 1 and an upper plenum spring 2, and as shown in FIG. , and is inserted into the storage column 15 which is held in a concentric position with the cladding tube 6 in a concentric position and displaced as shown by the arrow in FIG. 3, which shows the fitted state. Third
The dummy cylinder handling device 25 is not shown in the figure. Further, FIG. 3 shows a state in which the opening/closing mechanism is opened on the side of the chamber 7 opposite to the side on which the cladding tube 6 is attached.

FIG. 5 is a sectional view of the storage column 15 into which the cylindrical dummy 13 has been inserted and has come into contact with the cladding tube 6. The storage column 15 has one end of the main body of the apparatus, and the other end to which the cladding tube 6 is attached has a motor 24. The cylindrical dummy 13 is formed so as to be able to approach or separate from the cladding tube 6 side via a ball screw 19 or the like, and as shown in FIG. 3, the cylindrical dummy 13 is inserted at a separated position. The upper plenum spring 2 is inserted into the cladding tube 6, and is brought close to the cladding tube 6 side as shown in FIG. 1 when the upper end plug 1 is welded to the cladding tube 6. Further, the pusher 9 is inserted into the cladding tube 6 after the storage column 15 comes into contact with the cladding tube 6 as shown in FIG.
The upper plenum spring 2 is pushed inward, and the upper end plug 1 is brought into contact with the end surface. In the welding device, the upper end plug 1 is brought into contact with the cladding tube 6 in an inert gas atmosphere in the chamber 7, and welding is performed while both are driven to rotate integrally.

In FIG. 1, a cladding tube 6 filled with pellets 3 is fitted into one end of a chamber 7, and an upper end plug 1 is attached to the other end of the chamber 7. Cylindrical dummy 1 with built-in upper plenum spring 2
A storage column 15 is installed which holds the 3 inside.

The storage column 15 is supported by the chamber opening/closing table 12 and opens and closes the side of the chamber 7 opposite to the side on which the cladding tube 1 is attached, as described above.

The chamber opening/closing table 12 connects the power of the motor 24 to the coupling 23 . Driven via gear 21, bearing frame 20a,
Ball screw 19 supported by and rotationally driven by 20b
It is formed so that it can approach and be separated from the chamber 7 side via. A pusher 9 is loosely fitted into the axial center of the storage column 15, and the pusher 9 presses the upper end plug 1 by pressure from the pusher gas supply port 10 against the tension of the spring 11. In addition, an umbrella-shaped seal 16 is provided to seal the single cylindrical storage column 15 to the chamber 7, and the umbrella-shaped seal 16 is provided with an opening/closing spring 17 and an inert gas supply port 18 to supply inert gas. Mouth 18
When the pressure of the inert gas is released, the tension of the spring 17 releases the seal by the ♦-shaped seal 16, and the upper end of the chamber 7 is opened on the side where the plug 1 is attached. and,
Storage column 15. The pusher 9 is rotatably supported by a bearing 14 of a chamber opening/closing table 12, and has a synchronized rotation mechanism 26° gear 2.
The cladding tube 6 is rotatably driven through a gear 4, and the cladding tube 6 is synchronized with the cladding tube 6, which is rotationally driven through a gear 4.

As shown in FIG. 4, the upper plenum spring 2 and the upper end plug 1 are housed in a cylindrical dummy 13 of a first jig, and the cylindrical dummy 13 is a dummy cylindrical handling device 2 of a robot.
5, it is attached to the storage column 15 of the second jig at a position separated from the chamber 7, which is held concentrically with the cladding tube 6 attached to the chamber 7, as shown in FIG. The cylindrical dummy 13 and the dummy cylinder handling device 25 move the storage column 15 into which the cylindrical dummy 13 is inserted, forming the supply means for the upper end plug 1 and the upper plenum spring 2, by a motor 24. The cylindrical dummy 13 is moved through the ball screw 19 and the chamber opening/closing table 12 so that it comes into contact with the cladding tube 6, as shown in FIG. The cladding tube 6 is inserted with its end portion positioned from outside the chamber 7 using an optical camera (not shown). After the dummy cylinder 13 is set and the upper plenum spring 2 is inserted into the cladding tube 6, the storage column 15 is shifted away from the cladding tube 6 by about 5 to 10+w-. The amount of deviation is measured by detecting rotation with an encoder (not shown) attached to the ball screw 19.

Thereafter, the inside of the chamber 7 is evacuated through a vacuum device (not shown) and replaced with helium gas, and then the cylindrical column 15 is moved toward the cladding tube 6 again, and the upper end plug 1 is inserted by the pusher 9. . The pusher 9 moves in the direction away from the cladding tube 6 again while maintaining the pressure from the pusher gas supply port 10, and an optical camera (not shown) is used to maintain a predetermined distance between the cladding tube 6 and the cylindrical dummy 13. After checking, the cladding tube 6 and the upper end plug 1 are connected to the gear 27. The circumference is welded while rotating integrally with the gear 4 interposed. Further, the empty cylinder dummy 13 is removed from the storage column 15 by a dummy cylinder handling device 25 and taken out via a transfer device (not shown). The pusher 9 is returned to the position shown in FIG. 3 by the tension of the spring 11 when the gas pressure applied to the pusher gas supply port 10 is released. Then, the dummy cylinder handling device 25 attaches the upper end plug 1 and the upper plenum spring 2 to the storage column 15 via the cylindrical dummy 13, and the chamber 7 of the storage column 15 where the upper end plug 1 and the upper plenum spring 2 are installed. The upper plenum spring is inserted into the cladding tube 6 by the pusher 9, the upper end plug 1 is pressed into contact with the end surface of the cladding tube 6, and the upper end plug 1 is maintained in contact.

All rotating and circumferential welding operations are automatically coordinated and controlled by a controller (not shown).

In the reactor fuel rod end plug welding device of this embodiment, the upper plenum spring, which has a small diameter and a relatively long length, is housed in a cylindrical dummy and is located in the storage column, and the upper plenum spring is located at the same position as the storage column. It is inserted into the cladding tube held at Therefore,
The upper plenum spring can be easily and automatically inserted.

Therefore, the problem of the tip of the upper plenum spring hanging down and difficulty in positioning, which was the case in the past, is completely eliminated, and the number of work steps can be significantly reduced, and radiation exposure can be significantly reduced. Furthermore, since helium is replaced in a small chamber, helium gas can be saved, and the problem of incorrect insertion and positioning of the plenum spring can be prevented.

〔Effect of the invention〕

The end plug welding work for reactor fuel rods according to the present invention can significantly reduce the number of work steps and can significantly reduce radiation exposure.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view of a fuel element welded by the apparatus shown in FIG. 1, and FIG.
An explanatory diagram of the storage column shown in the figure separated from the cladding tube side, Figure 4 is a detailed view of the part ■ in Figure 3, and Figure 5 is a storage column with the cylindrical dummy attached in Figure 4 attached to the cladding tube. FIG. 6 is a perspective view of an operation in which the cylindrical dummy of FIG. 4 is mounted on a storage column.

Claims (1)

[Claims] 1. A lower end plug is sealed to one end of the fuel cladding tube, the inside is filled with helium gas, a plurality of pellets are stacked and filled from the bottom, and an upper plenum spring is attached to the other end. After insertion, the upper end plug is rotated in a chamber with a helium gas atmosphere inside, and the sealed portion is driven to rotate integrally with the fuel cladding tube, the inside of which is filled with helium gas. In the case where the upper end plug and the upper plenum spring are fixed by welding, the upper end plug and the upper plenum spring are built into an inner cylindrical dummy, and the cylindrical dummy is placed in a concentric position with respect to the fuel cladding tube which is held at an upper end in the chamber. means for mounting in the held storage column; and the cylindrical dummy is detachably mounted and formed to be integrally rotatable with respect to the fuel cladding tube. a storage column; the upper plenum spring in the cylindrical dummy is slidably installed at the axial center of the storage column; the upper plenum spring in the cylindrical dummy is inserted into the fuel cladding tube; and the upper end plug is pressed into contact with the fuel cladding tube when welded. A nuclear reactor, characterized in that it is provided with a pusher formed to be able to hold the means, the storage column, the pusher, and the welding device, and a control device that controls the operations of the means, the storage column, the pusher, and the welding device so that they are automatically performed in conjunction with each other. Fuel rod end plug welding equipment.