JP2000056069A - Refueling machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of the efficiency of the inserting/removing work of a fuel rod. SOLUTION: A J-shaped pawl 1A is suspended from the lower section of a leg 11b on the side of a bridge guide rail 6B via a pin 3A and a bush. The screw section of a bearing 2 is screwed to the lower end of the pawl 1A and fixed by a nut. A steel ball at the tip of the bearing 2 is kept in contact with the side face of the intermediate section of the guide rail 6B. A proximity sensor 5 is fitted to the lower end of the leg 11b to detect an increase of the interval between the guide rails 6B caused by the remaining heat of the operation of a reactor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel exchanger used for inserting and removing fuel rods of a boiling water reactor.

[0002]

2. Description of the Related Art FIG. 7 is a plan view showing an example of a conventional fuel exchanger, and FIG. 8 is a right side view of FIG. 7 and 8, the floor 10 on which the containment vessel 18 of the nuclear reactor is installed has
A refueling machine 9B that can travel freely via rails 6A and 6B installed on 10 is installed. The rail 6A at the rear of the drawing is the reference side, and the rail 6B at the front is installed parallel to the rail 6A.

The refueling machine 9B has a bridge 11 made of a large girder in the shape of a girder in FIG. 7 and a truss in FIG. 8, and legs 11a, 11a provided on the rail side of the bridge 11. 11b and a trolley 13 mounted on the upper part of the bridge 11 via a trolley rail 6C, 6D so as to be freely movable.

FIGS. 9 and 9 show enlarged details of the lower ends of both sides of the legs 11a and 11b.
A wheel 7 shown by a chain line in FIG. 10 showing a right side view of FIG. Therefore, the refueling machine 9B is positioned at a predetermined position for inserting and removing the fuel rod at each position (address) of the storage container 18 by moving the bridge 11 right and left in FIG. 7 and the trolley 13 back and forth in FIG. You.

[0005] For this purpose, a rack 27 is installed on the floor 10 on the right side of the front rail 6B in FIG. 8 on the paper surface, and a pinion gear (not shown) for meshing with the rack 27 and rotating the synchro oscillator is provided on the leg 11b. Built in.

Further, a rack 15 for position detection is installed inside the trolley rail 6C shown in FIG.
A pinion gear (not shown) meshing with 15 and a synchro transmitter are incorporated in the trolley 13.

In FIG. 7, a trolley is provided at the center on the left side.
A pair of cable reels 22 for supplying electric power to devices described below mounted on the trolley 13 are shown, and a fuel gripper 14 shown in FIG.

A wire (center line) for restricting the position of the lower gripping tool at the lower end of the gripping tool 14 and a power supply to the drum and the gripping tool at the lower end of the gripping tool are provided in front of the gripping tool 14 in the drawing. Cable (center line) and its drum 23
It is shown.

FIG. 9 shows the rail 6 shown on the rear right side of FIG.
FIG. 10 is an enlarged view of the right side of FIG. 9 and 10, the leg 11a of the bridge includes:
Bolts 24 and 25 are formed on the outside of the wheel 7 indicated by the dashed line with bolts 24 and 25 formed in a substantially T shape from a thick mild steel plate of 80 mm to 100 mm and having a pair of claw tips 19 a formed symmetrically at the lower end. It is tightened.

A roller support 21 made by welding in a U-shape in FIG. 9 is welded to the outer surface side of the claw 19A, and a pair of roller shafts 26 are vertically mounted on the roller support 21. The guide rollers 20 are inserted into the lower ends of these roller shafts 26, and the opposing surfaces of these guide rollers 20 correspond to the rails 6A.
Touching both sides of the head.

The above-mentioned claw 19A opposes the claw tip 19a with a gap close to the side and lower surface of the head of the rail, and the gap between the side of the head of the rail is about 3 mm.
It has become. On the other hand, the rail 6A is installed with an accuracy of ± 1 mm in linearity and parallelism with respect to a reference value.

FIG. 11 shows a claw 19B in which the rail 6B shown on the front right side of FIG. 8 is loosely fitted to the claw tip, and corresponds to FIG. 9, and FIG. 12 is a right side view of FIG. FIG. 11 is a diagram corresponding to FIG.

FIG. 11 shows only the middle part to the lower part of the claw 19B due to the restriction on the paper surface, but the shape and mounting structure from the middle part to the upper end are the same as those of the claw 19A shown in FIGS. 9 and 10. It is.

The difference is that there is no roller support 21 and roller 20 shown in FIGS. 9 and 10, and the shape of the claw tip is slightly different. The gap between the claw tip 19b and the rail 6B is the same as in FIG.

In the refueling machine constructed as described above, in the event of an earthquake, the head of the rail is loosely fitted to the lower end of the nail so that the nail fitted with the rail does not come off and the bridge does not fall. A substantially T-shaped recess is formed.

Further, by minimizing the gap between the width of the recess and the side surface of the head of the rail, the accuracy of the repetitive position of the bridge running on the rail is increased, and the fuel gripper 14 shown in FIGS. The efficiency of the fuel rod insertion / removal operation has been improved by increasing the accuracy of the position reproduction.

The address at which the fuel rod is inserted / removed (for example,
Before the reactor is installed and operated (power generation), the bridge 11 and the trolley 13 are driven in the X and Y directions and detected by the synchro transmitter. Is input to a control device mounted on the trolley 13.

The floor 10 on which the rails are installed is constructed on a pedestal made of a large channel steel or the like in order to improve earthquake resistance. The length of the rails 6A and 6B reaches 50 m when it is long, and the distance between the rails 6A and 6B is 20 m.
In some cases.

[0019]

However, in the fuel exchanger constructed as described above, after starting operation, when the fuel rod is lifted or inserted in order to replace the fuel rod on a predetermined replacement date, the heat capacity is increased. There is a temperature difference between the gantry and the bridge with a large floor due to the difference in cooling rate.

That is, since the distance between the rails 6A and 6B is wider than that before operation due to thermal expansion, the distance between the claws 6A and 6B incorporated in the bridge having a lower temperature than the floor is relatively large. There is a possibility that the side surface of the head of the rail 6B may come into contact with the claw 19b on one side.

Further, since the relative position between the fuel rod accommodated in the nuclear reactor and the gripper of the bridge also changes, it may take time to insert and remove the fuel rod. Therefore, an object of the present invention is to provide a refueling machine that can prevent a decrease in efficiency of fuel rod insertion / removal work.

[0022]

According to a first aspect of the present invention, there is provided a trolley, in which a bridge runs on a rail over a reactor pressure vessel and moves vertically on the bridge. And a J-shaped claw having one end rotatably mounted on the upper part of the rail of the bridge and a guide member attached to the other side of the rail, and the rotation of the claw. And a detector attached to the bridge for detecting the relative position with respect to the rail, and a correction control unit for correcting the position of the refueling machine according to the output of the detector. .

In the fuel exchanger according to the present invention, the rotation center of one end of the pawl is offset from the position of the center of gravity of the pawl, and the other end of the pawl is urged toward the rail by gravity. It is characterized by the following.

A fuel exchanger according to a third aspect of the present invention is characterized in that the detector detects the rotational displacement of the pawl instead of detecting the relative position with respect to the rail.

According to the first aspect of the present invention, the stopper and the tip of the claw prevent the upward movement of the bridge at the time of the occurrence of the earthquake and correct the change in the relative position between the bridge and the rail due to thermal expansion. It is corrected by the control unit.

In the invention according to the second aspect, the tip of the claw from the rail head during the occurrence of an earthquake is prevented from being released from the rail head by the pressing force applied to the rail by gravity applied to the claw. The detector detects the opposing relationship between the tip of the nail and the head of the rail.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the fuel exchanger according to the present invention will be described below with reference to the drawings. FIG. 1 is a partially enlarged detailed view showing a first embodiment of a refueling machine according to the present invention, and is a view corresponding to FIG. 11 shown in the prior art, and FIG. 2 is a right side view of FIG. FIG. 3 is a schematic plan view showing the operation of the first embodiment of the fuel exchanger according to the present invention.

First, FIGS. 1 and 2 are different from FIGS. 11 and 12 shown in the prior art in that the shape and mounting structure of the pawl, and a guide is attached to the pawl, and the relative position between the bridge and the rail is different. That is, a proximity sensor for detecting the position is provided.

That is, the nail 1A is connected to the leg 11b of the bridge.
In contrast to this, it is swingably provided vertically via a pin 3A and a bush 8, and has a substantially J-shape in FIG. A circular counterbore is formed on the right side surface of the claw 1A in FIG.

The pin 3A is positioned above the right end of the claw 1A.
A stopper pin 3B having the same shape as the above is fixed to the leg 11b, and the lower surface is opposed to the upper end surface of the claw 1A with a slight gap. leg
The upper end of a spring seat 11c is welded to the lower end of 11b, and a circular counterbore is formed on the left side surface of the spring seat 11c in FIG.

A coil spring 4 is inserted in a slightly compressed state between the counterbore and the counterbore on the right side of the above-described claw 1A. A shaft portion of a bearing 2 having a steel ball incorporated at a tip thereof is screwed into a projection formed at the lower end of the claw 1A, and after adjusting a protruding position, it is fixed with a nut.

Further, a mounting plate 28 formed in an L-shape in FIG. 2 is vertically provided on the lower end surface of the leg 11b.
The proximity sensor 5 is attached to 28 so that the detection unit is opposed to the rail 6B.

In the refueling machine constructed as described above, the steel ball at the tip of the bearing 2 is always pressed by the rail 6B by the claw 1A on which the clockwise moment acts in FIG.

Furthermore, a counterclockwise moment acting on the claw 1A due to an earthquake can be dealt with by the return force of the coil spring 4 and the upper stopper pin 3B. Can be eliminated.

The relative position of the rail and the leg in the horizontal direction is detected by the proximity sensor 5, and this detection signal is output to a control device for positioning the trolley of the refueling machine in the X and Y directions, and By correcting the position in the direction orthogonal to
The position of the gripper can be made even more precise.

FIG. 3 is a schematic plan view of the refueling machine for explaining a correction method for correcting the position of the gripper based on the result of detection by the proximity sensor 5. In FIG. 3, the dashed-dotted circle indicates the outer periphery of the containment vessel 18 of the reactor into which the fuel rod is inserted and withdrawn, and the trolley 13 of the refueling machine 9A is located above the central part of the containment vessel 18. Is shown.

At the right end of the storage container 18, a part of the address 17 of the fuel rod insertion portion is shown, and at the center of the bridge, a detection rack 15 shown in FIG. A synchro transmitter 16 connected to a pinion gear meshing with the central portion of the transmission is shown. The proximity sensor 5 is shown on both sides of the middle part of the left rail 6B, and the guide rollers 20 shown in FIGS. 9 and 10 are shown on both sides of the middle part of the right rail 6A.

In FIG. 3, the distance between the opposed rails 6A and 6B before the equipment is operated is _denoted by L _0, and the distance corrected by the control device with the value detected by the proximity sensor 5 is denoted by L. Further, when the distance portion and the jaws 14 of the insertion portion of the address 17 of the fuel rods measured before operation and L _x0, position L _x of the address 17 of the insertion portion of the fuel rod during replacement, L _x = By calculating and correcting L _x0 × L / L ₀ by the control device, the fuel rod insertion / removal operation can be performed smoothly regardless of the temperature difference between the gantry and the bridge.

In the above embodiment, the length of the pin 3A is increased, and a claw having the same shape as the right claw 1A is provided symmetrically on the left side as shown by a chain line in the figure. 4, the proximity sensor 5, and the stopper pin 3B may also be incorporated symmetrically. Further, instead of the coil spring 4,
A spiral spring may be inserted into the pin 3A to apply a moment force to the claw.

Next, FIG. 4 shows a second embodiment of the fuel exchanger according to the present invention.
1 is a partially enlarged detailed view showing the embodiment, and corresponds to FIG. 1 shown in the above-described embodiment, and is different from FIG. 1 in that the position of the center of gravity of the nail 1A shown in FIG. 1 is specified. In FIG.
The center of gravity position 12 of the claw 1A is located above the right end of the upper right end of the rail 6B because a portion facing the stopper pin 3B is formed at the upper right end.

As described above, by setting the shape of the claw 1A so that the center of gravity comes as far as possible from the line connecting the center of the pin 3A and the rail 6B, for example, due to location restrictions, FIG.
When the maintenance and inspection of the coil spring 4 becomes difficult, the pressing force of the steel ball at the tip of the bearing 2 on the rail 6B can be obtained even if the coil spring 4 is omitted.

FIG. 5 is a partially enlarged detailed view showing a third embodiment of a refueling machine according to the present invention, and corresponds to FIGS. 1 and 4 shown in the aforementioned embodiment. FIG. 6 is a right side view of FIG. 5 and also corresponds to FIG.

FIGS. 5 and 6 differ from FIGS. 1, 2 and 4 described above in the mounting position of the proximity sensor 5A, and are otherwise the same as FIGS. 1, 2 and 4. That is, as shown in FIGS. 5 and 6, the leg 11b of the bridge is adjacent to the stopper pin 3B on the right side in FIG.
In FIG. 6, a Z-shaped mounting plate 28B is fixed, and the proximity sensor 5 is fixed to the lower front surface of the mounting plate 28B. The detection unit of the proximity sensor 5 is opposed to the upper right surface of the claw 1a. ing.

In this case, even if a scratch or a dent or the like is formed on the side surface of the head of the rail 6B in the installation work or the subsequent maintenance / inspection work, the proximity sensor 5 is not affected. There is an advantage that detection accuracy can be prevented from lowering.

[0045]

As described above, according to the invention corresponding to the first aspect, the bridge runs on the rail over the reactor pressure vessel, and the fuel holding means is provided on the trolley moving vertically on the bridge on the rail. And a J-shaped claw having one end rotatably mounted on the upper part of the rail of the bridge and a guide member attached to the other side of the rail, and the rotation of the claw. A stopper attached to the bridge, which detects the relative position with respect to the rail, and a correction control unit that corrects the position of the refueling machine in accordance with the output of the detector. At the tip of the bridge, the upward movement of the bridge in the event of an earthquake was prevented, and the change in the relative position between the bridge and the rail due to thermal expansion was corrected by the correction control unit, thereby preventing the efficiency of fuel rod insertion / removal work from lowering. That fuel exchange can be obtained.

In particular, according to the invention corresponding to claim 2, the rotation center of one end of the pawl is offset from the center of gravity of the pawl,
By configuring the other end of the claw to be biased toward the rail by gravity, the tip of the claw from the rail head during the occurrence of an earthquake is prevented by the pressing force on the rail due to gravity applied to the claw. In addition, it is possible to obtain a refueling machine which can reduce the efficiency of fuel rod insertion / removal work and prevent a fall due to an earthquake.

According to the invention corresponding to claim 3,
Since the displacement of the claw is detected by the detector to improve the measurement accuracy of the relative position between the rail and the bridge, a fuel exchanger that can reduce the efficiency of fuel rod insertion / removal work and prevent falling due to an earthquake is obtained. be able to.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view showing a first embodiment of a refueling machine according to the present invention.

FIG. 2 is a right side view of FIG.

FIG. 3 is a schematic plan view showing the operation of the first embodiment of the refueling machine of the present invention.

FIG. 4 is a partially enlarged view showing a second embodiment of the refueling machine of the present invention.

FIG. 5 is a partially enlarged view showing a third embodiment of the refueling machine of the present invention.

FIG. 6 is a right side view of FIG.

FIG. 7 is a plan view showing an example of a conventional refueling machine.

FIG. 8 is a right side view of FIG. 7;

FIG. 9 is a partially enlarged view showing an example of a conventional fuel exchanger.

FIG. 10 is a right side view of FIG. 9;

FIG. 11 is a partially enlarged view showing an example of a conventional fuel exchanger different from FIG. 9;

FIG. 12 is a right side view of FIG. 11;

[Explanation of symbols]

1A: Claw, 2: Bearing, 3A: Pin, 3B: Stopper pin, 4: Coil spring, 5: Proximity sensor, 6A, 6B: Rail, 7: Wheel, 8: Bush, 9A, 9B: Refueling machine, 10: Floor, 11 Bridge, 11a, 11b Leg, 12 Center of gravity of claw, 13 Trolley, 14 Gripping tool, 15 Rack, 16 Synchro transmitter, 17 Address of fuel rod insertion part, 18 Storage Containers, 19A, 19B: claws, 20: guide rollers, 21: roller supports, 22: cable reels, 23: drums, 24, 25: bolts.

Claims (3)

[Claims] 1. A refueling machine comprising: a bridge running on a rail over a reactor pressure vessel; and a trolley moving on the bridge in a direction perpendicular to the rail, wherein a fuel holding means is mounted on the trolley. A j-shaped pawl having one end rotatably mounted on the upper part of the rail of the bridge and a guide member mounted on the other end for contacting the side surface of the rail; a stopper for restricting the rotation of the pawl; A detector attached to the detector for detecting a relative position to the rail,
And a correction control unit for correcting the position of the refueling machine in accordance with the output of the detector. 2. The apparatus according to claim 1, wherein the center of rotation of one end of the claw is offset from the center of gravity of the claw, and the other end of the claw is urged toward the rail by gravity. 2. The refueling machine according to 1. 3. The refueling machine according to claim 1, wherein the detector detects a rotational displacement of the claw instead of detecting a relative position with respect to the rail.