JPS62287182A - Upper nozzle assembly device for fuel aggregate - 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 3. Detailed Description of the Invention "Field of Industrial Application" The present invention relates to an upper nozzle assembly device for attaching a leaf spring to the upper nozzle of a fuel assembly by tightening it with a screw.

"Prior Art" Generally, a leaf spring is attached to the upper nozzle of a fuel assembly to suppress and support the fuel assembly downward in a nuclear reactor.

FIG. 6 shows an example of the upper nozzle, and the symbol l in the figure shows an example of the upper nozzle.
2 is a nozzle body, 2 is a leaf spring attached to the top surface of the nozzle body l, and 3 is a clamp.

The leaf spring 2 has a shape 17I2.5 at one end.
A through hole 4 formed on the upper surface of the nozzle body L or the hook portion 2a
Since it is hooked on the periphery of , it is elastically deformed downward, and a strong 1jiii force is applied upward.

The installation work of this kind of life spring 2...
Conventionally, this is done as follows.

First, as shown in FIG. 7, the hook portion 2a of the leaf spring 2 is inserted into the through hole 4 of the nozzle body l, and the hook portion 2a is hooked on the periphery of the through hole 4. Next, the fixed part 2b of the leaf spring 2 is positioned at a predetermined position on the nozzle body 1, the clamp 3 is placed there, and the screw 5 is lightly screwed into the hole in the nozzle body 1 through the hole in the clamp 3 and the fixed part 2b. Then, use a torque wrench to tighten the screws 5 to the specified torque, and tighten each screw 5.
- Fastening force in the axial direction (hereinafter referred to as tightening axial force)
are made to be approximately constant.

"Problem to be Solved by the Invention" By the way, since the torque required to rotate the screw 5 involves the frictional force between the screw 5 and each part and the elastic force of the leaf spring 2, this tightening torque is , does not correspond accurately to the tightening axial force of the screw 5, and there is considerable variation depending on each screw 5.

Further, since the torque wrench itself is not a highly accurate tool, it is not always possible to tighten the screw 5 with accurate torque.

Due to the accumulation of errors as described below, in the conventional leaf spring installation method, which only sets the tightening torque of the screws 5 with a torque wrench, the tightening torque of each screw 5.
The cone was used to maintain uniform and accurate tightening axial force. Therefore, it is strongly desired to further improve the reliability of tightening.

In addition, in the conventional method, the screw 5 is tightened while deforming the leaf spring 2, which has a strong elastic force, which requires labor to use a torque wrench, which places a heavy burden on the worker and takes time. There were also problems.

``Object of the present invention'' The present invention improves the tightening reliability of the screw by tightening the screw for fixing the leaf spring to the upper nozzle of the fuel assembly so as to obtain a highly accurate tightening axial force. It is an object of the present invention to provide an upper nozzle assembly device that can perform this tightening work simply and quickly.

"Means for Achieving the Object" The upper nozzle mounting device for a fuel assembly of the present invention includes a plurality of fixing mechanisms for pressing and fixing a fixed part of a leaf spring to a predetermined position of the upper nozzle, and a fixed part of the leaf spring. A tightening mechanism that screws and tightens the screw into the upper nozzle through the fixing part, an axial force measurement sensor that measures the internal stress of the screw generated by this tightening, and a torque measurement sensor that measures the tightening torque by the tightening means. It is characterized by having the following.

"Operation" In the present invention, first, l&
The fixed part of the leaf spring which has been subjected to γt is pressed down by the splinter fixing mechanism and brought into pressure contact with the upper surface of the two-part nozzle. Next, the screw that passes through the leaf spring fixing part and is screwed into the upper nozzle is tightened.

At that time, the axial force L! +++ A constant sensor measures the internal stress of the screw caused by tightening, calculates the tightening axial force from that value, and informs the operator of this. At the same time, a torque measurement sensor measures the tightening torque and detects an abnormal tightening of the screw, thereby preventing abnormalities such as screw seizure.

``Example'' Please refer to the lower 7M surface of L and 1 in 1977, and explain the example of water content t'+H in detail in this note.

FIG. 1 is a side sectional view of an upper nozzle assembly device for a fuel assembly according to one embodiment, and FIG. 2 is a front view of the same device.

First, to explain the general configuration of the entire device, reference numeral 11 in the figure
is a pedestal installed on the floor, and on this pedestal ll,
A disk-shaped rotary table I2 for holding the nozzle body I is installed on the part to be assembled. Further, in the vicinity of the rotary table I2, a spring fixing mechanism 13 is provided on the pedestal Ii for pressing and fixing the fixing part 2a of the leaf spring 2 against the two-part nozzle body l. Furthermore, a frame I4 is installed upright on the pedestal Ill2, and this frame 14 is provided with a tightening mechanism 15 for tightening the screw 5 to the upper nozzle body 1.

The rotary table 12 is rotatably mounted on a table support 16 mounted on a pedestal Il. In addition, the rotary table 12 and the table support stand 16
A positioning mechanism (not shown) is provided between them.
The table 12 is adapted to be locked in a sea that rotates 180°.

As shown in FIG. 3 (plan view), a pair of nozzle fixtures 18a and 18b are mounted on the upper surface of the rotary table 12, facing each other and spaced apart by 180 degrees. These nozzle fixtures 18a and 8b are grooves for sandwiching and fixing the four βJ corners of the upper nozzle body 1,
One nozzle fixed! 118a is fixed on the rotary table 12, and the other nozzle fixture +8b is attached to a clamp lever.
By rotating 19, 19, they can be moved toward and away from each other.

The spring fixing mechanism 13, as shown in FIG.
It is composed of a knolling stand 20 fixed on a pedestal Il, a swing touring stand 2I mounted upward on this knolling stand 20, and an arm 22 fixed to the rod end of this swing touring stand 21. There is.

The swing tool ring 21 is different from a normal hydraulic glue knob in that when hydraulic pressure is supplied, the protruding rod is rotated approximately 90 degrees and retracted.

Further, the arm 22 is fixed so as to face the center of the rotary table 12 when the swing tour cylinder 2I is operated and retracts the rod, and when the swing tour cylinder 21 is not operated, the arm 22 is fixed so as to face the center direction of the rotary table 12 when the swing tour cylinder 2I is operated and the rod is retracted. As shown by the middle two-dot chain line, it is located in a place where it does not interfere with the attachment and detachment of the upper nozzle body I. The tip of this arm 22 has a spring attachment hole 24.2 formed in the upper nozzle body 1.
Circular through holes 23.23 are formed at positions corresponding to 4, and these through holes 23.23 are inner holes into which a tightening tool, which will be described later, can be inserted.

Next, the frame 11 and the tightening mechanism 15 will be explained.

The frame Ill is composed of a lower frame 14a and an upper frame +4b. As shown in FIG. 1, the lower frame 14a can be moved in the front and rear directions (left and right directions in FIG. 1) on the pedestal 11 by operating a handle 25. Further, the upper frame 14b is attached to the lower frame 14a via a slide base 26, and by loosening the clamp lever 27, a stopper 28.28 (see FIG. 2) is attached to the lower frame 14a. The lower frame l 4 a can float in a direction perpendicular to the moving direction of the lower frame l 4 a.

A vertically extending screw shaft 29 is attached to the side surfaces of the upper frames l, ib and is supported by bearings 30, 30 at both ends. These two screw shafts are
A cap gear 31 is attached to the upper end thereof, and a cap gear 3 is pivotally supported by a bracket 32 at the upper end of the upper frame 14b.
3, and can be rotated by a handle 34.

Further, a post 35 is screwed onto the screw shaft 29, and a base plate 36 is attached to the post 35, and this base plate 36 moves up and down in accordance with the rotation of the two screw shafts. It has become. And, on this base plate 36, there is a reduction hole l'll'! 77 1-Fl”
L-1h Eihan 55suQ fortune 1] τ? -; City service 1 and attached (t).

The acid 3i2 decelerator 37 has a handle/IO attached to its human power shaft, and when the handle 40 is rotated, the rotation speed is reduced and transmitted to the torque converter 38.

On the other hand, the torque converter 38 transmits the rotation from the reducer 37 to the three connecting members attached to the lower end output shaft, so the first one is equipped with a strain gauge (torque measuring sensor). It is configured to convert distortion occurring in the internal rotating shaft into an electrical signal and transmit it to a display panel (not shown). This display panel is configured to convert the electrical signal into a torque value and display it as a work sound.

On the other hand, a bracket/I
A screw shaft 42 is attached vertically via I. This screw shaft 42 is rotatably operated by a handle 45 via a cap gear 13 and a cap gear 44 attached to the lower end thereof. Further, a tool support part it 11.7 is attached to the screw shaft 42 via a post 46, and when the handle 45 is turned, this tool support member 47 moves up and down.

The tool support member 47 includes rod-shaped tightening tools 48L, 4
8R are each mounted downward so as to be rotatable and slidable a certain distance.

Since these tightening tools 48L and 48fl have the same diameter, splines 49 and 49 are formed at the upper ends of each of them. Then, use one of the tightening tools (48L in the figure).
) is engaged with the spline connection 39 attached to the output shaft of the torque converter 38, so that the rotation from the reducer 37 is transferred to the tightening tool 48.
It is designed to be transmitted to L.

The tightening tool/18L (481) consists of a long support rod 50 and a single tool body 51 attached to its lower end. Below, regarding this tool body 5I, Fig. 4(a),
Please explain with reference to (b) and (c).

In the figure, the reference numeral 60 is a cylindrical outer cylinder, and the lower end of this outer cylinder 60 has an engaging part 60 that engages with the upper end of the screw 5.
a is formed. An axial force measurement sensor 61, a spring 62, and a spring retainer 63 are fitted inside this outer cylinder 60, and the axial force measurement sensor 61 is
It is biased downward by a spring 63 and slightly protrudes from the lower end of the outer cylinder 60.

The shaft horn measurement sensor 61 is 5M from its lower end! 4
It not only emits ultrasonic pulses of about z, but also receives the reflected waves and converts them into electrical signals, and is operated by a conopiuter (not shown). This computer measures the return time required from the transmission of the ultrasonic pulse to the reception of the reflected wave, calculates the tightening axial force from this return time, and displays it to the operator on a display (not shown). It is composed of

Here, the principle of measuring the tightening axial force of the screw 5 will be explained.

When the screw 5 is tightened to the upper nozzle body 1, tensile stress is generated inside the screw 5, causing elastic elongation. When the ultrasonic pulse reciprocates between the upper end and the lower end of the screw 5 (see FIG. 5), the speed change slows down due to the increase in stress within the screw 5.

At the same time, the extension of the screw 5 extends the propagation distance of the ultrasonic waves, which further delays the return time of the ultrasonic waves. Due to these two effects, the return time of the ultrasonic pulse becomes longer as the tightening axial force of the screw 5 increases. The screw 5 in the tightened state as shown in FIG. 5(b) serves as the base thread.
By measuring the increase in return time at , the tightening axial force can be calculated.

Next, how to use this upper nozzle assembly device will be explained.

First of all, leaf spring 2... and clamp 3
・Set in a predetermined position on the upper nozzle main body 1, and lightly screw in the screw 5 by hand to temporarily assemble it into the state shown in FIG.

Then, this temporarily assembled upper nozzle l is inserted between the nozzle fixtures 18a and 18b on the rotary table 12, and is fixed by tightening the clamp levers 19 and 19 of the nozzle fixture +8b.

Next, the swing-in ring 21 is operated to swing the arm 22.
Lower the clamp 3, press down the fixed part 2b of the leaf spring 2 from above the clamp 3, make it elastic and tightly contact the upper surface of the upper nozzle 1.

Next, operate the handle 25 as necessary to move the lower frame +4a back and forth to position it, and then turn the handle 45 to lower the tightening tools 48L and 48R, respectively. Fit the lower end of 18R to the screws 5, 5 temporarily assembled on the upper nozzle l, respectively. Then, the axial force measuring sensors 61, 61 at the lower end of each tightening tool 48L, 481 are pressed against the upper end surface of the screw 5.5 by the biasing force of the spring 62, 62, as shown in FIG. 5(a). .

First, in this pre-tightening state, the axial force measurement sensor 61 is activated, and the return time for the ultrasonic pulse to reciprocate from the upper end to the lower end of the screw 5 is measured and stored in the computer.

Next, the handle 40 is rotated, and the tightening tool 48L is rotated via the decelerator 37 and the torque converter 38 to tighten the screw 5.

At this time, the axial force measurement sensor 61 is activated again, and the return time of the ultrasonic pulse is measured by the computer. The measured regression time is then compared with the regression time before tightening, and the tightening axial force is calculated and displayed on the display. Thereby, the worker performs the tightening work while directly checking the tightening axial force of the screw 5, and stops the tightening work when the predetermined axial force value is reached.

In addition, in parallel with the measurement of the sleeve horn, the strain gauge inside the torque converter 38 is operated to measure the tightening torque, and the value is displayed on the display panel.

After tightening one screw 5 in this way,
Rotate the handle 34 to raise the three spline connectors and disengage the splines 49 of the tightening tool 48L. Then, operate the clamp lever 27 to move the upper frame 14b to the right in FIG.
to engage the spline connector 39 and the spline 49 of the other tightening tool 48R. and,
Similarly to the above, the tightening tool 118R is rotated to tighten the screw 5.

Thus, the screw 5.5 on the same side on the upper nozzle 1
When the tightening is completed, operate the handle 34 to remove the spline connector 39 from the tightening tool 48R, stop the oil rE supply to the swing cylinder 21, release the hold by the arm 22, and then remove the rotary table. 12 to 1
Rotate 80 degrees and screw the screw 5 on the other side of the upper nozzle 1.
．． Perform tightening in step 5.

According to the fuel assembly upper nozzle assembly device having such a configuration, the tightening axial force of the screw 5 can be directly and accurately measured by the axial force measurement sensor 61 at the lower end of the tightening tools 9↑8L, , 18R. Therefore, tightening work can be performed. Therefore, compared to the conventional case where the screw tightening torque is set using a torque wrench, it is possible to significantly improve the tightening reliability of the screw 5, and in turn, it is possible to improve the quality of the upper nozzle. It is.

In addition, since the screw 5 is tightened without measuring the tightening torque using the strain gauge in the torque converter 38, in the unlikely event that the screw 5 is repeatedly tightened, the tightening torque can be measured. It is possible to notify the operator immediately and prevent the screw from burning out.

In addition, since the screw 5 is tightened after the strong elastic force is applied to the spring spring 2 by pressing it in advance with the hydraulic pressure of the swing cylinder 21 and deforming it elastically, the spring 2 is deformed. Does not require the power of
Force required for tightening (force required to rotate the handle 40)
It is possible to reduce the amount of labor required by the operator.

Also, at the same time, the handle 4 is compared to the torque wrench operation.
Since the operation of turning 0 is easy, quick tightening operation is possible.
481 are fitted into the respective screws 5.5 at the same time, and then the screws 5 are tightened, so compared to the case where one tightening tool is replaced with each screw 5 and tightened, the time and effort required for replacement is reduced. It also has the advantage of being halved.

Furthermore, with this device, you can manually turn the handle 10 to finely adjust the tightening axial force when tightening.

In addition, instead of manual tightening, it is possible to use a motor or the like as a driving source for tightening, and to configure this motor to be controlled by a combiator. In that case, the screw 5
It is possible to automatically stop tightening when the tightening axial force reaches a predetermined value.

In addition, the above-mentioned device was configured to display the tightening axial force and torque using a display, but instead of using a display, it may be configured to notify the operator with a buzzer or the like when the value reaches a certain level. good.

"Effects of the Invention" According to the fuel assembly upper nozzle assembly apparatus of the present invention, the following effects can be obtained.

■Since the axial force measurement sensor allows you to perform tightening work while directly and accurately measuring the tightening axial force of the screw, it is possible to perform tightening work while directly and accurately measuring the tightening axial force of the screw. Tightening reliability can be significantly improved, and the quality of the upper nozzle can also be improved.

■The screw is tightened while checking the tightening torque using a torque measuring sensor, so if
Even if an abnormality in tightening occurs in the screw, this can be immediately notified to the operator, and it is possible to prevent the screw from seizing.

■The leaf spring, which has a strong elastic force, is held in place by the spring fixing mechanism before the screw is tightened, so no force is required to deform the spring, and the effort required for tightening is minimal. As a result, work speed can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an upper nozzle assembly device for a fuel assembly according to an embodiment of the present invention, FIG. 2 is a front view of the device, and FIG. 3 is a plan view showing the main parts of the device. Figure 4 (a) is a top view showing the tightening tool of the same device, (b) is a sectional view of the same tool, (c
) is a view of the same tool from below, and Figures 5(a) and (b)
) is a sectional view for explaining the action of the tool. Further, FIG. 6 is a perspective view of the upper nozzle, and FIG. 7 is a sectional view showing a conventional screw attachment method. ■... Upper nozzle body 2... Leaf spring 2a
・Spring fixing part 3・・Clap 5・Screw
I2 ・Rotary table 13... Spring fixing mechanism 14... Frame 15 Tightening mechanism 38...
Torque converter (torque measurement sensor) 48L, 48R/tightening tool 61 Axial force measurement sensor

Claims (1)

[Claims] A fixing mechanism that presses and fixes the fixed part of the leaf spring in a predetermined position of the upper nozzle, a tightening mechanism that screws and tightens a screw into the upper nozzle through the fixed part of the leaf spring, and internal stress of the screw caused by tightening. 1. An upper nozzle assembly device for a fuel assembly, comprising: an axial force measurement sensor that measures the torque of the tightening mechanism; and a torque measurement sensor that measures the tightening torque of the tightening mechanism.