KR20000059966A - PHWR Fuel Bundle Assembling and Welding Machine - Google Patents

Abstract

PURPOSE: An assembly welding device of CANFLEX fuel bundle is provided so that a new CANFLEX can be achieved with high productivity compared to the conventional CANFLEX bundle welder(10 bundles per time) by effectiveness of welding device. CONSTITUTION: The assembly welding device of CANFLEX fuel bundle includes several devices. A mechanism of a rotary arm type is constructed by combining a base frame(1), a column(2), an upper frame(3) and a transfer arm(5) on a column(2). The base frame(1) is constructed by four working positioned. A welding head(6) and an assembly rotation motor(10) are mounted to the upper frame(3). The transfer arm(5) are inserted to the column(2), rotated at the axis with a column(2) by using a rotation motor(10) and a timing belt(7) and transfers the CANFLEX to other working position. An upper frame(3), a base frame(1) and a transfer arm(5) are a combined structure on a column(2).

Description

PHWR Fuel Bundle Assembling and Welding Machine}

The present invention relates to a nuclear fuel bundle assembly welder for heavy water reactors, and more particularly, to the dimensional integrity and bond strength of nuclear fuel bundles for assembly and welding of CANFLEX fuel bundles consisting of two kinds of fuel rods of different diameters. It can be used for assembly and welding of nuclear fuel bundles for CANDU fuel, which is currently in operation, and can have up to 2 times higher production capacity than existing welding machines including current welding equipment. It relates to a bundle welder.

Until now, weld nuclear fuel bundles in the order of forward → welding → retraction → welding face conversion → forward → welding → retraction based on the welding head.

In the case of the nuclear fuel bundle welding machine currently used in Canada, since a heavy welding jig and a method of moving the fuel bundle are adopted, there is a high possibility of an error in the welding position control due to the rotational inertia of the fuel bundle.

In addition, the existing welding machine uses a welding electrode supported by a fixed shaft core, so even if the fuel rod and the welding electrode shaft are slightly misaligned, only one of the two ground electrode surfaces is in contact with the fuel rod or the welding strength is lowered due to incomplete contact. A problem occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and satisfies the dimensional integrity and joint strength regulation values of nuclear fuel bundles during assembly and welding of CANFLEX fuel bundles consisting of two types of nuclear fuel rods of different diameters. It can be used for assembling and welding nuclear fuel cell bundles of commercially available heavy water reactors, and can provide up to 2 times higher production capacity than existing welding machines including current welding equipment. The purpose is to make a bundle welding machine.

In the automatic welding device for producing a nuclear fuel bundle to achieve the above object;

High productivity of 20 ~ 24 bundles per hour, consisting of a rotary arm type transfer mechanism for moving the fuel bundle to the next process, a welding electrode drive device for driving the electrode to the welding position, and a welding electrode guide device for preventing the welding electrode from tilting. To provide an improvement in welding quality.

1 is a front view of a nuclear fuel bundle welder for the present invention heavy water reactor

2 is a plan view of the nuclear fuel bundle welder for the present invention heavy water reactor

Figure 3 is a block diagram of the present invention nuclear fuel bundle welding machine base frame

Figure 4 is a schematic view of the welding machine welding electrode drive device of the present invention

5 is a configuration diagram of the welding electrode guide device of the present invention

<Description of the code | symbol about the principal part of drawing>

(1): base frame (2): pillar

(3): top frame (4): cylinder

(5): transfer arm (6): welding head

(7): Timing belt (8): Aggregate presence or absence sensor

(9): detection sensor on the top and bottom of the assembly (10): motor for assembly rotation

11: X axis motor 12: Y axis motor

(13): motor for electrode rotation 14: ball screw

(15): X-axis guide table (16): Y-axis guide table

(17): rotational and linear motion shaft 18: sensor

19: welding electrode surface 20: spherical bearing

21: spring 22: head drive shaft

(23) Fixture jig

Referring to the configuration and operation of the present invention in detail based on the accompanying drawings as follows.

1 is a front view of the nuclear fuel bundle welding machine for the present invention,

2 is a plan view of the nuclear fuel bundle welding machine for the present invention;

3 is a configuration diagram of the present invention nuclear fuel bundle welder base frame,

4 is a configuration diagram of a welding electrode welding device of the present invention;

Figure 5 shows the configuration of the welding electrode guide device of the present invention.

An automatic welding device for producing a nuclear fuel bundle;

It consists of a rotary arm type transfer mechanism for moving the fuel bundle to the next process, a welding electrode drive device for driving the electrode to the welding position, and a welding electrode guide device for preventing the welding electrode from tilting.

Rotary arm type transfer mechanism (mechanism) is a structure in which the base frame (1) and the pillar (2), the upper plate frame (3) and the transfer arm (5) on one pillar (2) The base frame 1 is composed of four work positions, the upper frame 3 is equipped with a welding head 6 and an assembly rotation motor 10, and a transfer arm 5 ) Is a device for moving the nuclear fuel bundle to the next work position while rotating the pillar 2 in the axis by using the rotating motor 10 and the timing belt 7 while being fitted to the pillar 2.

In this case, the upper frame 3, the base frame 1, and the transfer arm 5 are coupled to the pillar 2, and the transfer arm 5 is a rotating motor on the base frame 1. It is comprised by the structure which rotates using the 10 and the timing belt 7. As shown in FIG.

The structure is excellent in work efficiency and work because welding preparation work (nuclear fuel rod visual inspection and assembly) can be carried out simultaneously with welding in two spaces except two that are welded out of four work positions. It's fast and you can use your workspace efficiently.

The welding electrode drive device includes three X-axis and Y-axis electrode rotating motors 11, 12, 13 and two ball screws 14, which cause longitudinal and axial symmetric rotational movements of both welding heads 6. It consists of one timing belt (7) and receives the control signal corresponding to the welding position from the PC to drive the X-axis, Y-axis electrode rotation motors 11, 12, 13 and the ball screw connected to each motor ( 14) and the apparatus as shown in FIG. 4 for vertical and horizontal movement of the electrode by the timing belt 7.

4, the X-axis, Y-axis electrode rotation motor 11, 12, 13, the ball screw 14, the X-axis guide table 15, the Y-axis guide table 16, the rotary and linear motion shaft ( 17) and the guide table is much lighter than the nuclear fuel bundle because the welding electrode is transverse, vertical and rotational movement has the advantage of minimizing the occurrence of errors and rapid position movement when welding position control.

The welding electrode guide device is composed of a spherical bearing 20 journal, a shaft and a spring 21 and a welding electrode surface 19, and when the welding electrode comes down to the welding portion during welding, the electrode surface is placed on the upper inclined surface of the end cap. It is a device to adjust the inclination angle according to the amount of eccentricity of the electrode from the end cap shaft axis so as to apply pressure by uniform contact.

The guide device includes a welding head 6 having a spherical journal bearing 20, a shaft, a spring 21, a welding electrode surface 19, and the like, when the welding head 6 descends toward the nuclear fuel bundle. When the ball is moved in the direction of the arrow to contact the fuel bundles by the action of the spherical bearing (20) journal it can act to prevent the bending moment that can be applied to the shaft by the difference between the welding electrode surface 19 and the fuel rod inclination angle. .

When the nuclear fuel bundle automatic welding machine of the present invention is examined in detail, it is a device for resistance welding of nuclear fuel rods in which sintered body loading and end cap welding have been completed with two end plates. It is a dedicated machine and is used in the process which is very important in obtaining the designed power in the reactor by maintaining the dimensional integrity and bonding strength by maintaining a constant interval between each fuel rod.

The newly developed welder has a base frame (1) having four work positions, a pole (2) having a rotary type transport arm (5), a welding electrode (19) and a power supply. , Top plate frame (1) on which various parts such as assembly rotation motor (10), assembly presence, detection sensor (8) and assembly upper and lower detection sensors (9) are mounted. Compared to the conventional welding machine of the structure or the straight flow work structure, the work is easy in the narrow space and the working speed is more than twice as fast.

The base frame (1) is divided into two welding work positions and two welding preparation work positions, and in the welding work position, the nuclear fuel transferred to the welding work position by the nuclear fuel bundle transfer arm (5) fixed to the column (2). Positioning projections and the presence or absence of fuel bundles, and the top and bottom of the fuel bundles, which serve to allow the bundle fixing jig to be positioned at a position where the center of the welding electrode 19 and the center of the nuclear fuel bundle can be exactly matched. There are sensors 8, 9 which can be identified.

The sensor 18 detects the nuclear fuel bundle fixing jig 23 until it stops above the positioning projection, and the rotary transfer arm 5 rotates the X- and Y-axis electrodes. After rotation by (12) (13), the cylinder (4) connected to the column (2) retreats and the welding is made after the transfer arm (5) holding the fixing jig (23) is lowered.

Welding is performed after the base electrode and the branch electrode part located on the upper plate frame 1 above the fixed nuclear fuel bundle are brought into contact with each other in a descending welding position.

At this time, the welding head 6 moves to the electrode position corresponding to each fuel rod through the horizontal and vertical movements and the rotational movement about the electrode axis with respect to the cross section of the nuclear fuel, and rotates the electrodes to control the position, and not the fuel bundle. It is distinguished from the conventional welder in that it drives an electrode.

Welding position control drives three X-axis and Y-axis electrode rotating motors 11, 12 and 13 with a control amount (rotation) corresponding to the welding position from a PC, and the X-axis and Y-axis electrode rotating motors. The welding head 6 is moved to the welding position by the timing belt 7 connected with (11) (12) and (13).

At this time, the welding position can be flexibly selected according to the selected welding mode, and the nuclear fuel rod and the end-bonded plate are welded as the welding variable set in the welding part after sensing the upper and lower detection sensors 9 of the nuclear fuel bundle.

When welding is completed for each fuel rod, lift the nuclear fuel bundle fixing jig 23 fixed to the transfer arm 5 by the hydraulic cylinder, rotate to the next work position, and then retract the hydraulic cylinder. Descend again. Then, the welded nuclear fuel bundle is lowered from the transfer arm 5 and the newly prepared nuclear fuel bundle fixing jig 23 is fixed to the transfer arm 5 or the upper and lower sides are reversed. This rotates again.

As shown in FIG. 3, two of the four working positions have welding electrodes, and the other two are welding workspaces for arranging nuclear fuel rods in a specially designed jig and fixing the end junction plate, and thus, a work space for inspection during manufacturing. Welding and preparatory work can be carried out at the same time. The user can freely select whether to use only one work position or two simultaneously. The welded nuclear fuel bundle can be taken out from the jig using a host and limit guide mounted with the top frame 1.

When welding is made, welding power of high frequency inverter type is used as welding power source and resistance welding is performed by using base electrode and branch electrode. After transferring to the welding position, the pressure of the welding head (6) consisting of the base electrode and the branch electrode is lowered to the end surface of the nuclear fuel bundle by the pressure of the pneumatic valve, and the current flows through the base electrode and the branch electrode. Welding is performed by generating heat of resistance at the contact point of the fuel rod and the end junction plate receiving current from each electrode.

When the welding head 6 is lowered and the electrode surface is in contact with the welding position, when the center of the fuel rod and the center of the welding head do not coincide, the inclination of the electrode is automatically generated by the spherical bearing 20 journal according to the eccentric amount. While being compensated, the contact area between the welding electrode surface 19 and the welding electrode contact point is maximized.

After the electrode touches the welding part, the pressing force transmits the pressing force corresponding to each welding position from the PC to the controller and pressurizes through the valve by this control amount. Thus, welding variables such as pressing force, current, and energization time at each fuel rod welding position Can be set freely, it is possible to obtain better welding quality (bond strength and dimensional integrity) than conventional nuclear fuel bundles.

Therefore, the present invention adopts an inverter type power supply that can satisfy the welding strength while minimizing the amount of heat input, and at the same time, the welding machine can be used efficiently by making the welding machine small and light. In addition, because welding current is stable and concentrated, welding defects such as indentation (pressed traces) and socho (burning of heat) are prevented to improve welding quality, and thermal efficiency is high, resulting in reduced welding cycle time and productivity.

In addition, unlike the welding machine used in Canadian fuel producers, the electrodes are positioned using three micro stepping motors, encoders, and sensors to prevent errors in the welding position of each fuel rod. Minimized.

The structure of the welding head is designed to automatically adjust the inclination when the inclined surface and the branch electrode of the end cap are eccentric so that uniform pressure can be applied to both electrode surfaces, thereby improving welding quality (bond strength and dimensional integrity). .

In addition, the base and the frame are fixed to one pillar, and the work is performed while rotating around the pillar, which facilitates access and monitoring during operation, as well as welding and welding at four working positions on the base. The work efficiency was maximized by simultaneously performing assembling work.

In addition, by directly controlling the stepping motor, sensors, and welding parameters using a PC, and freely changing the welding mode, it is possible to arbitrarily select the top and bottom of the nuclear fuel bundle using the same welding head as well as the welding parameters for each position. The selection of (current, energization time and welding pressure) is much more flexible than existing equipment.

Due to the above control method, characteristics of welding power source and efficiency of welder structure, the new fuel bundle welding machine can achieve higher productivity (20 to 24 bundles per hour) and welding quality than the existing fuel bundle welding machine (about 10 bundles per hour). will be.

Claims (7)

An automatic welding device for producing a nuclear fuel bundle; Assembly of nuclear fuel bundles for heavy water reactors comprising a rotary arm type transfer mechanism for moving the fuel bundle to the next process, a welding electrode driving device for driving the electrode to the welding position, and a welding electrode guide device for preventing the welding electrode from tilting welding machine. The method of claim 1; In the rotary arm type (mechanism), the base frame (1) and the pillar (2), the upper plate frame (3) and the transfer arm (5) are combined on one pillar (2), and the base Four work positions exist in the frame 1, and a welding head 6 and an assembly rotation motor 10 are mounted on the upper frame 3, and the transfer arm 5 has a pillar ( 2) the device is configured to move the nuclear fuel bundle to the next work position while rotating the column 2 in the axis by using the rotary motor 10 and the timing belt 7 while being fitted in the step 2). A nuclear fuel bundle assembly welder for heavy water reactors. The method of claim 1; The upper frame 3, the base frame 1, and the transfer arm 5 are coupled to the pillar 2, and the transfer arm 5 is timingd with the rotating motor 10 on the base frame 1. A nuclear fuel bundle assembly welding machine characterized in that it is configured to rotate using a belt (7). The method of claim 1; The welding electrode drive device includes three X-axis and Y-axis electrode rotating motors 11, 12, 13 and two ball screws 14, which cause longitudinal and axial symmetric rotational movements of both welding heads 6. Receiving a control signal corresponding to the welding position from one timing belt 7 and a PC, the X and Y axis electrode rotating motors 11, 12 and 13 are driven and connected to each motor. And a nuclear fuel bundle assembly welder configured to vertically and horizontally rotate the electrode by a timing belt (7). The method of claim 1; X-axis, Y-axis electrode rotation motors 11, 12, 13, ball screws 14, X-axis guide table 15, Y-axis guide table 16, rotary and linear motion shafts 17, A nuclear fuel bundle assembly welder according to claim 1, wherein the welding electrode is configured to perform horizontal, vertical and rotational movements by the guide table. The method of claim 1; The welding electrode guide device is composed of a spherical bearing 20 journal, a shaft and a spring 21, a welding electrode surface 19, an electrode frame 18, and the like. A fuel cell assembly welding machine for heavy water reactors, characterized in that it is configured to adjust the inclination angle according to the amount of eccentricity of the electrode from the end cap shaft axis so that the electrode surface contacts the inclined surface uniformly. The method of claim 1; When the welding head 6 descends toward the nuclear fuel bundle, that is, the welding head 6 portion composed of the spherical journal bearing 20, the shaft, the spring 21, the welding electrode surface 19, and the like moves in the direction of the arrow. By the action of the spherical bearing (20) journal when in contact with the fuel bundle is characterized in that it is configured to prevent the bending moment that can be applied to the shaft by the difference between the inclined angle of the welding electrode surface 19 and the fuel rod A nuclear fuel bundle assembly welder for heavy water reactors.