JP2969434B2 - Welding method of outer joint of water channel square tube in boiling water reactor fuel assembly and its welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel assembly for a boiling water reactor, which has been adopted for high burn-up, and which includes a water channel end plug and the like. A welding method for welding the outer peripheral surface of a square or hexagonal water channel square tube with a TIG or laser welding means or the like, and providing a welding method for performing the same. It relates to a welding device to be obtained.

[0002]

2. Description of the Related Art As is known, as shown in FIG. 6, a fuel assembly a for a boiling water reactor has a large number of fuel elements d and a water channel between an upper tie plate b and a lower tie plate c. e is vertically mounted and held apart by a plurality of required spacers f. Here, the above water channel e, those called conventional round is used, which is the upper end plug e ₁ and the lower end plug e ₂
Preparative butt up and down each end of the respective water channel round tube e _3, in which is communicated deposited by welding means in this state.

In the case of the conventional round type, when performing welding, the position of a welding head in a welding torch, an optical processing head, or the like is adjusted after fine adjustment and fixed. _After mounting the outer peripheral surface of the weld formed by butting the ₁ and the water channel round tube e ₃ ,
And the upper end plug e ₁ and the water channel round tube e ₃ so as to be integrated, and so as to rotate about the axis thereof. By doing so, the welding interval, which is the distance between the welding head and the outer peripheral surface of the welding during the rotation, is naturally kept constant. As long as the rotation is performed, satisfactory welding results will be obtained.

However, with the increase in burnup of this kind of fuel assembly, in recent years, a rectangular water channel 1 as shown in FIG.
In this case, the connection round pipe 4 is first round-welded to the upper end plug 2 at the upper welding portion 3a as shown in FIG. The upper end of the connecting member 5 is round-welded at the lower welding portion 3b,
The lower end corner of the connection member 5 is configured to be square-welded to the upper end corner of a square or hexagonal water channel square tube 6 at an upper square mouth welding portion 6a. The lower end corner of the lower end plug 7 is square-welded with the upper end corner of the lower end plug 7 at the lower corner mouth welding portion 6b.

Therefore, in the rectangular water channel 1, TIG or laser welding is performed at the two places of the upper square mouth weld 6a and the lower square mouth weld 6b as described above. In the case of the square pipe shown in FIG. 7B, the conventional welding means of this kind is used for each side face composed of the flat portion 6c and the left and right circular arc-shaped corner portions 6d. A welding operation is performed, and the operation is repeated four times.

[0006]

Therefore, according to the above-mentioned conventional example, continuous welding work cannot be performed, so that not only the workability is extremely poor, but also the arc-shaped corner portion 6 described above.
In the case of d, etc., an overlapped portion of the welding work is inevitably generated, and as a result, excessive heat input to the water channel square pipe 6, the connecting member 5, and the lower end plug 7 is unnecessarily given. This increases the undesirable thermal effect, which is likely to cause welding defects and the like, and, depending on the welding location, the welding depth and the like become non-uniform. Not only problems but also quality problems have been pointed out.

The present invention has been made in view of the above-mentioned disadvantages of the prior art, and in the welding method according to the first aspect, the water channel square tube and the welding member are integrally rotated while being kept in contact with each other. In this case, instead of rotating at a uniform rotation speed, the welding outer peripheral surface is divided into a required number of welding zones such as a plane portion and an arc-shaped corner portion,
The rotation speed is set in advance for each welding zone. And, corresponding to each of these rotational speed setting values,
By using the vector control central processing unit for the welding head described above, the vector is set so that the welding interval, the swing angle with respect to the welding outer peripheral surface, and also the relative speed with respect to the welding outer peripheral surface are always kept constant. By performing the adjustment displacement by control, and by providing predetermined program software to the vector control central processing unit, high-precision high-speed welding can be automatically performed by continuous rotation of the water channel square tube. It is an object of the present invention to provide a welded product having extremely excellent quality while also solving the problem of the overlap portion and the like.

Further, in the case of the welding apparatus according to the second aspect, as described by the above welding method, the vector control central processing for inputting the respective rotation speed set values for each of the required number of divided welding zones. A chucking driven rotation mechanism for holding the welding member is provided by the device, and a chucking rotation drive mechanism for the work that rotatably holds the water channel square tube, and a welding head that can be freely moved from the outer peripheral surface of the welding. By controlling the welding interval adjustment mechanism that can be changed to the above and the welding head swing angle adjustment mechanism that enables the welding head to swing freely by a predetermined angle along the welding outer peripheral surface, The aim is to carry out the welding method smoothly without hindrance.

[0009]

According to the present invention, in order to achieve the above object, according to the first aspect, the water channel square tube and the welding member are coaxially arranged, and each of the welding ends is provided. The welding outer peripheral surface is formed so as to be held in an abutting state, and the vector control central processing unit performs the welding of the water channel square tube by making a single rotation continuously in a predetermined direction with the axis as a rotation axis. For each welding zone obtained by dividing the outer peripheral surface into a required number, while rotating based on the rotational speed set value inputted respectively, and for the welding head of the welding machine mounted on the welding outer peripheral surface. The vector control central processing unit controls the welding head so that it can be displaced in the perspective direction from the welding outer peripheral surface in accordance with each of the rotation speed setting values, and the rotation axis and the rotation axis. By controlling to be able to swing freely along the welding outer peripheral surface in the intersecting direction, the welding head is always kept at a welding interval from the welding outer peripheral surface and a swing angle with respect to the welding outer peripheral surface. And a method of welding a water channel square tube outer peripheral joint in a fuel assembly for a boiling water reactor, wherein the relative speed with respect to the water channel is maintained constant.

[0010] Further, according to claim 2, the base includes:
A chucking rotary drive mechanism for a work in which a water channel square tube is rotatably held by a first power source with its axis as a rotation axis; and a water channel square tube on the same axis as the water channel square tube. A chucking driven rotation mechanism that holds the welding member so that a welding outer peripheral surface is formed by abutting against the welding end of the square pipe,
A welding interval adjusting mechanism for driving a welding head of a welding machine mounted on the outer peripheral surface of the welding machine so as to be movable by a second power source in a perspective direction from the outer peripheral surface of the welding, and the welding head; In the direction perpendicular to the rotation axis of the chucking rotation drive mechanism for the workpiece, and
The water channel angle is connected to the welding head swing angle adjusting mechanism, which can be swung by a power source, the chucking rotation drive mechanism for work, the welding interval adjusting mechanism, and the welding head swing angle adjusting mechanism. Each rotation speed of the water channel square tube is set for each welding zone obtained by dividing the welding outer peripheral surface of the pipe into a required number, and the welding head is always set to the welding outer circumference in accordance with the rotation speed. A fuel assembly for a boiling water reactor, comprising: a vector control central processing unit to which a welding interval with respect to a surface, and a calculation formula for keeping a swing angle and a relative speed constant are provided. To provide a welding device for a water channel square tube outer peripheral joint in the above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the welding method according to the first aspect of the present invention, a welding apparatus according to a second aspect will be described in detail with reference to FIGS. Drive mechanism 11, chucking driven rotation mechanism 1
2, a welding interval adjusting mechanism 13, and a welding head swing angle adjusting mechanism 14 are provided, and the remaining three mechanisms 11, 1 excluding the chucking driven rotation mechanism 12 are provided.
Numerals 3 and 14 are connected to a vector control central processing unit 15 provided at a desired place, and are configured to be controlled by outputs thereof as described later.

First, the work chucking rotation drive mechanism 11 will be described in detail. The work chucking rotation drive mechanism 11 includes a first power source 11a such as a motor shown in FIG. 2 and a chucking section 11b rotated by the first power source 11a. The water channel square tube 6 has its axis lined in the Y-axis direction in the example of FIG.
The chucking portion 11b is detachably held by the chucking portion 11b, and can be rotationally driven by the first power source 11a about the axis as the rotation axis 11c. In FIG. 2, 11d denotes the first power source. 11a motor cable, 11e reduction gear, 11f transmission pulley, 11g
Is a transmission belt, the rotation of which is transmitted to the chucking portion 11b by these transmission members, and 11h is the chucking portion 1b.
Reference numeral 1b denotes a rotation receiving bearing, and 11i denotes a chucking air introduction pipe.

The water channel square tube 6 loaded in the above-mentioned chucking rotary drive mechanism 11 for a workpiece has its welding end extended to a welding space 16, and through the welding space 16, The chucking driven rotation mechanism 12 for holding the connection member 5 and the welding member 17 serving as the lower end plug 7 is provided in a fixed manner. The connecting member 17 which is loaded so as to be detachable therefrom is connected to the rotation axis 11c.
By operating the illustrated transfer air cylinder 12a, the welding member 17 can be moved back and forth in the Y-axis direction.
Can be brought into contact with the welding end of the water channel square tube 6 held by the chucking portion 11b. As a result, the first power source 11a is operated, so that the welding member 17 Is a water channel square tube 6
Can rotate with it.

In the illustrated example, the welding space 16 is formed in a welding chamber 18, which is located on the upper wall side and includes a welding torch, an optical processing head, and the like. An opening 18a is opened so that the welding head 14a described later can be inserted. As a specific example, the upper wall and the front wall of the welding chamber 18 are transparent with acrylic resin. Are formed so as to be detachable by slide grooves (not shown), and both side walls are formed of stainless steel. Further, in the welding space 16 in the welding chamber 18, Ar gas and He gas are filled with a shielding gas introduction pipe 18 as shown in the figure.
By b, it blows in from below and improves the quality of a welding product.

Next, the welding interval adjusting mechanism 13 and the welding head swing angle adjusting mechanism 14 will be described. These adjusting mechanisms 13 and 14 are arranged in the left-right direction (Y-axis direction) in FIG. First handle 19a and first clamp 1
9b, the slide adjustment can be performed to a predetermined position with respect to the base 10, and the welding head swing angle adjusting mechanism 14 can also be adjusted to the position shown in FIG. 2 by the second handle 20a and the second clamp 20b. In addition, slide adjustment can be performed to a predetermined position with respect to the welding interval adjusting mechanism 13 in the vertical direction (X-axis direction), and by such adjustment, the welding head 14a can be moved to the water channel as described above. The welding end of the square tube 6 and the welding end of the welding member 17 are caused to collide with each other so that the welding outer peripheral surface 21 formed by the collision can be oriented and mounted.

The welding interval adjusting mechanism 13 is
By operating the second power source 13a by the servo motor or the like, the elevating rotary shaft 1 in the Z-axis direction in the standing state is operated.
3b is rotated so that the welding head swinging angle adjustment mechanism 14 is controlled to be able to move up and down. Accordingly, the welding head 14a is configured as described above. With respect to the welding outer peripheral surface 21, it can be changed in the distance direction. Here, 13c in the figure indicates a motor cable connected to the second power source 13a.

The above-described welding head swing angle adjusting mechanism 1
As shown in FIG. 3, the lifting base 14b, which is configured to be movable up and down by rotation of the lifting rotary shaft 13b, is shown in FIG. 1 and FIG. A drive transmission shaft 14e that is rotated by a third power source 14c such as a motor via a speed reducer 14d is provided. A first link 14f disclosed in FIG. 3 is axially mounted on the drive transmission shaft 14e.
The second transmission shaft 14g pivotally attached to the free end of the first transmission shaft 4f has the second transmission shaft 14g.
The base end of the link 14h is axially mounted. Further, the free end of the second link 14h has a second transmission shaft 14i.
The welding head 14a is fixed downward to the second transmission shaft 14i in a direction perpendicular to the second transmission shaft 14i. In the figure, reference numeral 14j denotes a motor cable connected to the third power source 14c.

Further, a chain (not shown) is tightly wound around the drive transmission shaft 14e, the first transmission shaft 14g, and the second transmission shaft 14i. When the drive transmission shaft 14e is rotated by the driving of the power source 14c, the rotation is transmitted to the first transmission shaft 14g and the second transmission shaft 14i as shown in FIG. 3, and as described later in detail. As shown in FIGS. 3 (A), 3 (B), and 3 (C), the welding head 14 a
1, the head can be swung in a direction orthogonal to the rotation axis 11 c, and the swing angle θr with respect to the welding outer peripheral surface 21 can be adjusted to a desired angle. Here, FIG. 3D shows a lifting base 14 which moves up and down by the operation of the second power source 13a.
4B shows the vertical movement stroke.

Therefore, when the welding method according to claim 1 is to be carried out by using the above welding apparatus, the water channel square pipe 6 and the welding member 17 are each driven by a chucking rotary drive mechanism for work. 11 and the chucking driven rotation mechanism 12, and the welding object is brought into an abutting state by the operation of the transfer air cylinder 12 a to form a welding outer peripheral surface 21. Source 1
By the operation of 1a, the two members 6 and 17 are integrally rotated once around the rotation axis 11c. In the present invention, prior to the rotation, the welding outer peripheral surface 21 of the water channel square tube 6 is divided into a required number of welding zones 21a as shown in FIG. 2
1b, 21c, the vector control central processing unit 1
By using 5, the desired rotational speed set value is input to this.

That is, in FIG. 1B, a water channel square tube 6 which is a square tube is exemplified, and a welding outer peripheral surface 21 defines a welding start point S as a bisecting point of the plane portion 6c. The half plane portion is defined as a first welding zone 21a,
The arc-shaped corner portion 6d continuing to this is set as the second welding zone 21b, and the subsequent 1/2 plane portion is set as the third welding zone 21b.
Is defined as the welding zone 21c of the first,
By repeating the 90 ° rotation over the second and third welding zones four times in total, 1
The rotation will end.

In the welding method according to the present invention, predetermined program software is set in the vector control central processing unit 15 so that the welding head 14a corresponding to each rotation speed set value is set. Is controlled so that it can be displaced in the perspective direction from the welding outer peripheral surface 21 by the operation of the second power source 13 a in the welding interval adjusting mechanism 13, and the third power in the welding head swing angle adjusting mechanism 14. By controlling the operation of the source 14c so that the head 14a can be swung freely in a direction orthogonal to the rotation axis 11c, the welding head 14a is constantly moved to the welding outer peripheral surface 2.
1 and the swing angle θr, which is preferably a right angle to the welding outer peripheral surface 21, and the welding outer peripheral surface 21
Is kept constant.

When the welding method described above is used, the torch angle θ _T of the welding head 14a is adjusted to a vertical line 0 as shown in FIG.
It is changed in the positive and negative directions around the center within a predetermined angle range, and
At the same time, with respect to the rotation amount (rotation angle θ) of the welding outer peripheral surface 21 and the welding outer peripheral surface 21 and the welding head 14 with reference to FIG.
torch height B corresponding to the welding interval, which is the distance from
Is adjusted. Then, this time, the rotational speed variation of the correction of the welding outer peripheral surface 21 is carried out by combined correction of the torch height B above the torch angle theta _T, thereby welding the outer peripheral surface 2
The relative speed of the welding head 14a with respect to 1 is made constant, and the welding interval and the swing angle θr, that is, the heat input angle, are kept constant over the entire surface of the welding outer peripheral surface 21.

Here, a specific example of the case where the above control is performed by the vector control central processing unit 15 will be described. As shown in FIG.
1b and 21c, the first welding zone 2
In the case of 1a, it is controlled by the following formula. Referring now to FIG. 5, the arrow indicates the direction of rotation of the water channel square tube 6, and A indicates the welding start point S.
, The welding angle on the welding outer peripheral surface 21, θ is the rotation angle of the water channel square tube 6, θ _T is the welding head 14
The torch angle of a, R is 1 / of the water channel square tube 6.
Two opposite side lengths, B indicates the torch height which is the distance from the axis of the water channel square tube 6 to the welding point, and Ro indicates the radius of curvature of the arc-shaped corner portion 6d. In the first welding zone 21a, θ is from 0 ° to tan ^-1 (R-Ro / R).
To the degree, A is a change from 0 to (R-Ro), where B = A / sin [tan ^-1 (A / R)] θ = sin ^-1 (A / B) θ _T = θ However, when A = O, θ = tan ⁻¹ (A / R) = 0.
0 θ = tan ^-1 (A / R) = 0.0 B = R / cos θ = R

Next, if the calculation formula in the second welding zone 21b is shown, θ is calculated from tan ^-1 (R-Ro / R) to ta.
In n ^-1 (R / R-Ro) degrees, A is (R-Ro) to (R
−Ro) + 2πR / 4.
Are as follows. β = A− (R−Ro) / Ro Y = Ro · sin β Z = Ro · cos β B = [(R−Ro) + Y] / sin [tan ⁻¹ (RR
o + Y) / (R-Ro + Z)] θ = tan ^-1 ｛[(R-Ro) + Y] / [(R-Ro)
+ Z]｝ θ _T = θ−β

The calculation formula in the third welding zone 21c is as follows. Here, θ is tan ⁻¹ (R / R−R
o) From degrees to 90 °, A is (R−Ro) + 2πRo /
4 to 2 (R−Ro) + 2πRo / 4, where B = R / sin @ tan ⁻¹ [R / ((R−Ro) −A +
(R-Ro) + 2πRo / 4)｝ θ = cos ^-1 [[(R-Ro) -A + (R-Ro) +2
πRo / 4] / B｝ θ _T = − (90 ° −θ) = θ−90 °

According to the control based on the above formulas, in the case of the water channel square tube 6 which is a square tube as shown in the figure, the welding for 1/4 turn is completed.
By repeating such control only four times, welding over the entire outer peripheral surface 21 is performed. In the illustrated welding apparatus, the welding outer peripheral surface 21
Is arranged in a shielding gas atmosphere in the welding chamber 18 instead of being disposed in the welding space 16 in the air, thereby improving the quality of the welded portion.

[0027]

Since the present invention is constructed as described above, when the welding method according to the first aspect is used, the water channel square pipe is separately provided for each welding zone such as a flat portion or an arc-shaped corner portion. In addition to setting by the vector control central processing unit to rotate at the rotation speed of the welding head, vector control is performed on the welding head, the welding interval and the swing angle with respect to the welding outer peripheral surface are always constant, and the welding outer peripheral surface is Since the welding head is controlled so that the welding speed is constant, the welding by rotating the welding outer peripheral surface continuously can be performed on the water channel square tube, and high-speed welding can be performed. Can be. Moreover, the weld does not have any heat-affected parts as in the conventional method,
Since welding under uniform thermal conditions over the entire circumference can be performed with high precision, the quality can be remarkably improved.

Further, in the case of using the welding apparatus according to the second aspect, the vector control central processing unit can use not only the chucking rotation drive mechanism for the workpiece and the chucking driven rotation mechanism but also the welding interval adjustment mechanism and the welding head swing angle. Since the adjusting mechanism is connected so as to be controllable, the welding method according to claim 1 can be performed with high precision, and it is possible to use not only a polygonal tube including a square tube but also a conventional round tube. The water channel can be easily handled by changing the program software in the vector control central processing unit.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a front view of a partially cut-out front view of a welding device for a water channel square pipe outer peripheral joint according to a second embodiment of the present invention, and FIG. It is explanatory drawing of the welding zone which divided | segmented this about the welding outer peripheral surface of required number.

FIG. 2 is an explanatory plan view illustrating a configuration of the welding apparatus of FIG. 1;

FIGS. 3A, 3B, and 3C respectively show an adjustment state of a swing angle according to a welding head swing angle adjusting mechanism of the welding apparatus of the above welding apparatus, at the start of welding, and at the first arc-shaped corner portion; It is each right side structural explanatory view at the time of welding and at the time of the last arc-shaped corner part welding.

FIG. 4 is an explanatory view showing a torch angle adjustment range of a welding head in the welding apparatus.

FIG. 5 is an explanatory diagram for a welding zone for illustrating a calculation formula of program software set in the vector control central processing unit when welding a water channel square pipe by the welding apparatus in the first embodiment.

FIG. 6 is a front view schematically showing a longitudinal section of a fuel assembly for a boiling water reactor using a round water channel.

FIG. 7 (A) is a front view of a partially cutout relating to a square water channel, and FIG. 7 (B) is a cross-sectional plan view showing the water channel square tube.

[Explanation of symbols]

 Reference Signs List 6 water channel square tube 10 base 11 chucking rotation drive mechanism for work 11a first power source 11c rotation axis 12 chucking driven rotation mechanism 13 welding interval adjustment mechanism 14 welding head swing angle adjustment mechanism 14a welding head 17 Welding member 21 Weld outer peripheral surface 21a Weld zone 21b Weld zone 21c Weld zone

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁶ , DB name) G21C 3/32 GDB B23K 9/00 501 B23K 9/12 331 B23K 37/00 G21C 21/00

Claims (2)

(57) [Claims] A water channel square tube and a welding member are formed on the same axis to form a welding outer peripheral surface such that respective welding ends are held in an abutting state, and the axis is a rotating shaft. As the center, when making one continuous rotation in a predetermined direction, the vector control central processing unit divides the welding outer peripheral surface of the water channel square tube into required numbers, for each welding zone obtained by dividing the welding outer peripheral surface into a required number. With the rotational drive based on the speed set value, for the welding head of the welding machine mounted on the welding outer peripheral surface, by the above-described vector control central processing unit, corresponding to each of the rotational speed set values, The welding head is controlled so that it can be displaced in the near and far directions from the welding outer peripheral surface, and the head can be swung freely along the welding outer peripheral surface in a direction orthogonal to the rotation axis. The head for welding, always the welding interval from the welding outer peripheral surface, the swing angle with respect to the welding outer peripheral surface,
A method of welding a water channel square pipe outer peripheral joint in a fuel assembly for a boiling water reactor, wherein a relative speed with respect to a welding outer peripheral surface is also kept constant. 2. A water channel square tube is provided on a base,
A chucking rotation drive mechanism for a work held rotatably by a first power source with its axis as a rotation axis; and a coaxial axis with the water channel square tube and a welding end of the water channel square tube. By abutting, the chucking driven rotation mechanism that holds the welding member so that the welding outer peripheral surface is formed, and the welding head of the welding machine mounted on the welding outer peripheral surface is moved away from the welding outer peripheral surface. A welding interval adjusting mechanism that is driven so as to be movable in a direction by a second power source, and the welding head is arranged in a direction orthogonal to the rotation axis of the workpiece chucking rotation drive mechanism, and along the welding outer peripheral surface. A welding head swing angle adjusting mechanism that can swing freely by three power sources, the above-described chucking rotation drive mechanism for work, a welding interval adjusting mechanism, and a welding head swing angle. The rotation speed of the water channel square tube is set for each welding zone obtained by dividing the welding outer peripheral surface of the water channel square tube into a required number, and the rotation speed of the water channel square tube is set to the rotation speed. Correspondingly, the welding head is provided with a vector control central processing unit to which a calculation formula for keeping the welding interval with respect to the welding outer peripheral surface, the swing angle and the relative speed constant is always provided. A welding device for a water channel square pipe outer peripheral joint in a fuel assembly for a boiling water reactor.