JP2002181988A - Fuel assembly assembling equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel assembly assembling equipment capable of automation of screwing work of screws and nuts and fully automating attaching work of end fixing members to the both ends of a temporary assembly. SOLUTION: In the automatic assembling equipment for fuel assembly for a light water reactor, an upper treatment device and a lower treatment device are provided for attaching an upper and a lower fixing members of individual structures to the upper and lower ends of the temporary assembly fixed and held in laid state on an assembling stage and for fitting both the ends of the fixing objective element to penetration socket holes of each of the upper and the lower end fixing members. Also the upper treatment device and the lower treatment device are provided with a screwing device for screwing screws, nuts and the like in the tip end of the fixing objective element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel assembly assembly for a light water reactor, and more particularly to a BWR.
Automatically mounting the upper tie plate and lower tie plate in assembling the fuel assembly for (boiling water reactor) or automatically mounting the upper nozzle and lower nozzle in assembling the fuel assembly for PWR (pressurized water reactor) The present invention relates to a device for screwing screws and nuts at the time.

[0002]

2. Description of the Related Art In assembling a fuel assembly for BWR,
Fuel is provided by a plurality of spacers to be arranged at intervals in the height direction of the fuel assembly and one to several water pipe elements (water rods or water channels) arranged at positions corresponding to several cells in the spacers. A skeleton for an assembly is formed, and fuel rods are inserted into a plurality of fuel rod storage cells in the skeleton, and the fuel rods are bundled together with the water pipe elements in a square lattice arrangement at intervals substantially parallel to each other. A temporary assembly is formed, and an upper tie plate and a lower tie plate as end fixing members having a unique structure are manually aligned and fixed to one end and the other end of the temporary assembly, respectively. The whole outer periphery is surrounded by a channel box, and the assembly is completed.

In this case, the element to be fixed on the temporary assembly side to the upper and lower end fixing members such as the upper tie plate and the lower tie plate is a water pipe element such as a water rod or a water channel or one or several fuel rods as a tie rod. Correction of misalignment based on error factors such as dimensional tolerances of both the temporary assembly and the end fixing element so that the ends of these fixing target elements are securely fitted into the through socket holes on the end fixing member side. I was doing it by hand.

[0004] The same applies to the assembly of a fuel assembly for a PWR. In this case, a plurality of support grids to be arranged at intervals in the height direction of the fuel assembly and a part of the support grid within the support grid are provided. A fuel assembly skeleton is constituted by a plurality of control rods and in-furnace instrumentation guide thimble tubes arranged at the cell position, and fuel rods are inserted into a plurality of fuel rod storage cells in the skeleton. These fuel rods and the respective guide thimble tubes are spaced apart substantially in parallel to each other to form a bundled temporary assembly in accordance with a square lattice arrangement, and each end of the temporary assembly has an end fixing member having a unique structure, that is, one end. The upper nozzle was fixed on the side and the lower nozzle was fixed on the other end by manual alignment and mounting.

In this case, the upper and lower end fixing members such as the upper nozzle and the lower nozzle are attached to the temporary assembly by using each of the guide thimble tubes in the temporary assembly as a fixing target element and a plurality of through-holes on the end fixing member side. In order to ensure that the ends of the plurality of corresponding elements to be fixed on the temporary assembly side are completely fitted into all of the socket holes, a positional shift based on error factors such as dimensional tolerances of both the temporary assembly and the end fixing element is performed. It was done manually with individual corrections.

However, when attaching the end fixing members to both ends of the temporary assembly of the fuel assembly in this manner, each fixing target element on the temporary assembly side is individually manually inserted into each through socket hole on the end fixing member side. If the fitting is performed while correcting the misalignment, it takes time and effort, and particularly in the case of assembling a uranium-plutonium mixed oxide (MOX) fuel assembly, a long manual work is required. There is a need for a shift to automation not only from the perspective of improving efficiency but also from the need to reduce radiation exposure.

Therefore, an automatic assembling apparatus for mechanically assembling a fuel assembly has been considered. As a procedure for assembling a fuel assembly by such an automatic assembling apparatus, first, a skeleton including a spacer and a guide thimble tube or a tie rod is formed, and a fuel rod is drawn into each lattice opening in the skeleton to temporarily assemble the temporary assembly. After that, a general method is to attach end fixing members such as upper and lower tie plates or upper and lower nozzles to the upper and lower ends of the temporary assembly.

In order to mount such an end fixing member, the tips of a plurality of fuel rods held in a square lattice arrangement must be fitted almost simultaneously with the corresponding through-holes of the end fixing member. Normally, however, in mechanical assembly by a device, the temporary assembly is fixed and held sideways, and the end fixing members are inserted and fitted to the upper and lower ends by horizontal movement from the left and right directions. Will be done.

In such a fitting method, the position of the tip end of the fuel rod is not always on the center axis of the through socket hole of the end fixing member positioned in the horizontal direction. Guide means are provided for guiding each fuel rod while automatically correcting the positional deviation from the through socket hole of the end fixing member.

[0010]

However, in assembling the fuel assembly, the fixing of the end fixing member may require not only fitting the tip of each fuel rod into the through socket hole but also screwing work. . For example, in the BWR type, the tie rod fuel rods protrude from the upper tie plate by an amount corresponding to the longer length of the upper end plug as compared with the standard fuel rods, and the fixing operation is completed by screwing a lock nut into this protruding part.

In the PWR type fuel assembly, a screw is screwed into the lower end of the control rod guide thimble pipe fitted into the through-hole of the lower nozzle from the bottom side of the nozzle to thereby control the control rod guide thimble pipe. The fixing to the lower nozzle is completed.

As described above, various screwing operations are required for assembling the temporary assembly on the upper and lower sides. Therefore, in order to automate the assembly of the fuel assembly, it is necessary to automate the screwing work of the various screws and nuts as described above.

In view of the above problems, an object of the present invention is to provide a fuel assembly assembling apparatus capable of completely automating an operation of attaching an end fixing member to both ends of a temporary assembly of a light water reactor fuel assembly. In particular, an object of the present invention is to provide a fuel assembly assembling apparatus capable of automating a screwing operation of screws and nuts.

[0014]

According to a first aspect of the present invention, there is provided a fuel assembly assembling apparatus according to the first aspect of the present invention, wherein a plurality of fuel rods are arranged substantially in parallel with each other in a square lattice arrangement. An automatic assembling apparatus for a fuel assembly for a light water reactor for attaching upper and lower end fixing members having a unique structure to upper and lower ends of a temporary assembly held in the temporary assembly, respectively, such that an axis of the temporary assembly is substantially horizontal. And an upper end fixing member which can be arranged and arranged on the assembling table in the direction of extension of the axis, and which is to be attached to one end corresponding to the upper end of the temporary assembly. An upper handling device for fitting an end of the element to be fixed, which is exposed at one end of the temporary assembly, to a through-hole in the upper end fixing member, and aligned with the assembly table in the direction in which the axis extends. Possible, corresponding to the lower end of the temporary assembly A lower handling device for holding a lower end fixing member to be attached to the end side and fitting an end of a fixing target element exposed at the other end of the temporary assembly to a through socket hole of the lower end fixing member, When the fitting of the end of the element to be fixed includes completion of screwing and fixing screws and nuts to a tip end penetrating a corresponding through-hole and protruding from the fixing member, the upper handling The device and the lower handling device each include a screwing device for screwing a screw or a nut to a tip portion of the element to be fixed, on a side opposite to the temporary assembly of a fixing member to be held.

According to a second aspect of the present invention, there is provided a fuel assembly assembling apparatus according to the first aspect, wherein the screwing device includes a fixing target element to which a screw and a nut are screwed. A holding unit that is releasably held toward the tip of the unit, a rotation mechanism that rotates the holding unit in a direction that is screwed around a central axis of the fixation target element, and at least the holding unit and the rotation mechanism in a temporary assembly. And a drive mechanism for horizontally moving so as to be able to approach and separate from the temporary assembly. With the rotation of the holding mechanism holding the screws and nuts by the rotation mechanism, the holding mechanism is moved to the temporary assembly by the drive mechanism. The screws and nuts are screwed into the front ends of the corresponding elements to be fixed by horizontally moving in the approaching direction.

The present invention can be applied to any assembly of a fuel assembly for BWR and a fuel assembly for PWR. The "temporary assembly" referred to in the present invention is a fuel assembly for BWR. A plurality of spacers to be arranged at intervals in the height direction of the fuel assembly and one to several water pipe elements such as water rods or water channels arranged at positions corresponding to several cells in the spacers. By inserting tie rod fuel rods and standard fuel rods into the storage cells of the skeletons thus formed, these fuel rods are bundled together with the water pipe element at intervals substantially parallel to each other to form a bundle-like structure according to a square lattice arrangement. Means something, also PW
In the case of the R fuel assembly, a plurality of support grids to be arranged at intervals in the height direction of the fuel assembly and a plurality of control rods and furnaces arranged at some cell positions in the support grid. By inserting fuel rods into the storage cells of the skeleton constituted by the internal instrumentation guide thimble pipes, the fuel rods are bundled together with the respective guide thimble pipes at intervals substantially parallel to each other and in accordance with a square lattice arrangement. Means a structure in the shape of a circle.

The term "end fixing member" as used in the present invention means an upper tie plate and a lower tie plate in the case of a BWR fuel assembly, and an upper nozzle and a lower nozzle in the case of a PWR fuel assembly. In other words, these tie plates and nozzles have a unique structure on the upper side and the lower side of the temporary assembly for BWR or PWR, respectively.

The term "element to be fixed" as used in the present invention refers to a component on the temporary assembly side to be inserted into a through socket hole of the end fixing member. In the case of a BWR fuel assembly, a water rod or a water channel is used. One or several fuel rods and standard fuel rods as water pipe elements and tie rods,
In the case of the PWR fuel assembly, the control rod guide thimble tube and the in-furnace instrumentation guide thimble tube which constitute the skeleton correspond to this.

In assembling a fuel assembly by the fuel assembly assembling apparatus according to the present invention, a temporary assembly prepared in a previous process is present on an assembly table, and a plurality of fuel rods are spaced substantially parallel to each other. The temporary assembly, which is held in a square lattice array, is fixed on an assembly table in a sideways state so that its axis is substantially horizontal.

In the present invention, one end of the temporary assembly is attached to the tip of the upper end handling device arranged in the extension direction of the axis of the temporary assembly with respect to the assembly table, and A lower end fixing member to be mounted on the other end side of the temporary assembly is attached to a tip end of a lower end handling device arranged in a direction opposite to the upper end handling device in the extension direction of the axis, and The fixing members are provided with through socket holes for receiving and fixing the ends of the elements to be fixed exposed at both ends of the temporary assembly, respectively. The upper and lower end fixing members are mechanically attached to the temporary assembly by moving the upper and lower end fixing members toward the temporary assembly while fitting the ends of the fixation target elements corresponding to the through socket holes to be inserted into the fuel assembly. The body can be assembled automatically, It is possible to improve the reduction and work efficiency of exposure of personnel.

Further, in the present invention, the fitting of the end portion of the element to be fixed includes one which is completed by screwing and fixing screws and nuts to the tip end protruding from the fixing member through the corresponding through socket hole. At this time, each of the upper and lower handling devices is provided with a screwing device for screwing screws and nuts into the distal end portion of the element to be fixed on the side opposite to the temporary assembly of the fixing member to be held, so that manual operation has been performed so far. It is possible to automate even the screwing work, which has been performed, and the fuel assembly assembly work can be more fully automated.

As a specific configuration of the screwing device, as described in claim 2, screws and nuts are held by the holding portion so as to be openable toward the tip of the element to be screwed. The holding unit is rotated by a rotation mechanism in a direction in which the holding unit is screwed around the central axis of the fixed target element to be screwed in, and the driving mechanism can move at least the holding unit and the rotation mechanism horizontally in a direction toward and away from the temporary assembly. With this configuration, the driving mechanism moves the holding section horizontally in the direction of approaching the temporary assembly with the screwing rotation of the holding section holding the target screw / nuts by the driving mechanism, thereby obtaining the screw / nut. The nuts can be screwed into the tip of the corresponding element to be fixed.

In such a screwing device, if the holding portion can be replaced with a screw or nut which is actually held, the same screwing device structure can be used to change the shape of the fuel assembly and the fixing member. It is possible to cope with different types. In addition, the configuration of the holding portion may be appropriately prepared corresponding to the target screw / nuts.However, the screw / nuts can maintain a sufficient holding force until the screwing operation is completed, and after the screwing operation is completed. And a mechanism that can easily release the holding state of the screw / nut.

For example, in a BWR fuel assembly, when an upper tie plate is attached to one end of a temporary assembly by an upper handling device, a lock nut is screwed into a tip end of a tie rod fuel rod protruding from the upper tie plate. As the holding portion of the screwing device installed in the upper handling device, a device capable of holding the lock nut from the outer periphery and easily releasing the holding state by retreating by the drive mechanism after the screwing work is attached, and a fuel for PWR. In the assembly, when the lower nozzle is attached to the other end of the temporary assembly by the lower handling device, a thimble screw screw is screwed into the lower tube end of the control rod guide thimble tube from below the through socket hole of the lower nozzle. In some cases, the thimble screw screw is used as a holder for the screwing device installed in the lower handling device. Parts may be configured to mount what may easily release the locking state retracted by screwing work after the end of the drive mechanism and is possible to be capable of transmitting the locking retention of the rotational movement.

In the screwing device of the present invention, at least the holding portion and the rotating mechanism are horizontally moved by the driving mechanism so that the screws and nuts held by the holding portion are brought close to the front end of the target fixing element. However, the design of the drive mechanism for horizontally moving the entire screwing device is simple in design.

However, the screw-and-nuts and the like can be further advanced by horizontal movement of the entire device by the drive mechanism, while the screw-and-nuts are in contact with the tip of the fixing element and rotated for screwing. If it is difficult to finely control the horizontal movement of the screwing device, a mechanism for partially moving only the holding portion in the screwing direction may be provided separately from the overall movement of the screwing device.

For example, there is a device in which a spring mechanism is incorporated between the holding unit and the rotation mechanism. In other words, even after the screws and nuts of the holding part have come into contact with the tip of the fixed element, if the entire device is further advanced by the drive mechanism for the horizontal movement required until screwing is completed, the spring mechanism is contracted, The screws and nuts of the holding portion are pushed in the screwing direction while maintaining the contact position by the urging force generated by the force. Therefore, if the screw and nuts are screwed and rotated through the rotation of the holding portion by the rotation mechanism, the urging force of the spring mechanism becomes a propulsive force with the rotation, and the screws and nuts are screwed to a predetermined position. Lead screwing can be completed.

Further, in such a screwing device, the screw and nuts need to be aligned with the tip of the target fixing element at the start of screwing. It is desirable to provide a position detector for confirming that the vehicle has come to the location.
Such a position detector can be widely used as long as it can confirm the positions of the holding portion or the screws and nuts, but a device design which occupies as small an area as possible and is simple is preferable. For example, a sensor using an optical sensor and a sensor using a proximity sensor can be used.

Further, it is preferable that the position detector can be used to confirm that the screws and nuts are screwed in a predetermined amount. For example, since the screwing of the nut proceeds by a certain stroke, if the detection target is provided at the holding portion position corresponding to the stroke, the completion of the screwing can be confirmed by the detection.

Further, it is desirable to provide a means for confirming the completion of the screwing in addition to the position detector. For example, if the thread pitch of the threaded portion into which the nut is screwed is known, the number of rotations of the nut until the screwing is completed can be calculated by the stroke / pitch. By installing a rotation detector for monitoring the number, it is possible to confirm that the required number of rotations has been performed and the screwing has been completed, and it is also possible to detect when unintended biting of the screw has occurred. For example, a device using a microphotosensor and a slit plate, a device using a rotary encoder, and the like can be used.

Normally, a screwing operation is often required for a plurality of fixing elements in one temporary assembly. Therefore, the screwing device includes a set of screwing operation parts of a holding unit and a rotating mechanism. The present invention is not limited to a configuration having only a plurality of fixing elements, and a plurality of sets may be provided to simultaneously perform a screwing operation on a plurality of fixing elements.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel assembly assembling apparatus according to an embodiment of the present invention will be described below together with an embodiment shown in the drawings, taking as an example the assembly of a fuel assembly for BWR. FIG.
1 is an overall configuration diagram of a fuel assembly assembly device of the present embodiment,
FIG. 2 is a schematic configuration diagram of an upper handling device provided with a screwing device of the assembling device. FIG. 3 is a partially enlarged view showing a shape of a holding portion. FIG. 4 is each operation for explaining a screwing operation by the screwing device. It is a partial schematic diagram in a process.

In this embodiment, as shown in the side sectional view of FIG. 8, the water channel 3 is arranged in a cell occupying an area corresponding to the center 3 × 3 fuel rods of a plurality of spacers 4 to be arranged at intervals. 9x9 skeleton composed
In the temporary assembly 10 in which eight tie rod fuel rods 2 and 64 standard fuel rods are inserted into the storage cells of the square lattice arrangement, the tip of each fuel rod is inserted into the through-hole of the upper tie plate 6. 7 and the upper extension 8 of the tie rod fuel rod 2 protruding through the through hole socket hole 7.
A description will be given of an assembling apparatus which is intended to complete the fixing of the upper tie plate 6 to the temporary assembly 10 by screwing the lock nut 9 into the assembling apparatus.

The present assembly apparatus for mounting the upper tie plate 6 and the lower tie plate 5, which are end fixing members, to the BWR temporary assembly 10 mainly includes a BWR temporary assembly, as shown in the schematic configuration diagram of the entire apparatus in FIG. An assembling table 40 fixedly held in a horizontal position so that the axis of the assembly 10 is substantially horizontal; and an upper tie plate 6 arranged on both sides of the assembling table 40 in the direction in which the axis of the assembling table 40 extends. Handling device 30 for lower and lower handling device 5 for lower tie plate 5
0.

As shown in FIG. 2, the upper handling device 30 supports the upper tie plate 6 at the tip end facing the assembly table 40, moves close to the temporary assembly 10, and moves to one end of the temporary assembly 10. The upper end of each fuel rod exposed to the
The upper fixing member mounting device 31 that fits into the through socket holes 7 of the upper tie plate 6 while being guided by 1 and the upper end extension portion 8 of the tie rod fuel rod 2 after being fitted into the through socket holes 7 of all the fuel rod tips. A screwing device 32 for screwing the lock nut 9 and fixing it with a washer is provided.

The horizontal (approaching) movement of the upper fixing member mounting device 31 to the temporary assembly 10 for mounting the upper tie plate 6 (fitting the tip of the fuel rod into the through socket hole) is performed by the entire upper handling device 30. The screwing device 32 can be moved horizontally independently by a dedicated drive mechanism (not shown) in the upper handling device 30 if the screwing device 32 is configured to be able to move horizontally in order to start screwing work. The detachment movement after the screwing operation can be easily controlled as a separate step from the fitting operation of the upper tie plate 6.

The screwing device 32 performs a screwing operation by rotating the lock nut 9 with respect to the upper end extension 8 of the tie rod and pushing it into the temporary assembly 10 while rotating the lock nut 9, and a rotating mechanism for giving a screwing rotary motion. A torque motor 33 is provided, and the rotational motion of the torque motor 33 is transmitted via a joint 34 to a threaded rod 35 whose tip is a holding portion 36 for holding the lock nut 9.

The threaded rod 35 of this embodiment has a spring mechanism 37 inside and can be expanded and contracted in the horizontal direction. In this case, the urging force generated when the spring mechanism 37 is contracted is used as a driving force for screwing the lock nut 9.

In the present embodiment, the lock nut 9 is held by the holding portion 36 so that the lock nut 9 does not come off and fall due to vibrations when moving close to the temporary assembly 10. Although a mechanism capable of maintaining a sufficient holding force is required, it is assumed that the holding state of the lock nut 9 can be easily released after the screwing is completed. For example,
As shown in the partially enlarged view of FIG. 3, if the holding mechanism using the ball plunger 22 is used, the lock nut 9 can be moved only by the retreat of the holding unit 36 due to the detachment movement of the screwing device from the temporary assembly 10 after the screwing is completed. It can be easily released without damaging the surface.

The screwing operation of the lock nut 9 into the upper end extension 8 of one tie rod fuel rod 2 by a set of screwing operation parts from the torque motor 33 to the joint part 34, the screw rod 35, and the holding part 36 as described above. However, the present invention is not limited to the configuration in which the screwing operation units provided in the upper handling device 30 are provided as one set, and a configuration in which a plurality of sets of screwing operation units are provided to simultaneously screw the lock nut 9 into a plurality of tie rods. Is also good. In the BWR fuel assembly assembled in the present embodiment, eight tie rod fuel rods 2 are arranged, and if the screwing device 32 has eight sets of screwing operation parts, the lock nuts 9 for all the tie rod fuel rods 2 can be used. Screwing work can be performed at once.

In order to start the screwing operation, the holding portion 36 must reach a position where the lock nut 9 contacts the tip of the upper end extension 8 of the target tie rod fuel rod 2. The alignment of the position of the holding portion 36 with respect to the upper end extension portion 8 of each tie rod fuel rod 2 is preliminarily set together with the corresponding through socket hole 7 of the upper tie plate 6 in accordance with the arrangement position of the tie rod fuel 2 in the temporary assembly 10. The position adjustment in a plane orthogonal to the central axis of the three-dimensional object 10 may be performed by a method using an imaging device such as an industrial television camera. Thus, the positioning of the holding portion 36 may be performed only by confirming the position of the horizontal movement on the tie rod fuel rod axis.

Therefore, in the present embodiment, the screwing device 3
2 is a position detector 38 for confirming the position of the holding unit 36.
Was provided. As the position detector 38, the screwing device 32
It can be confirmed that the holding portion 36 has reached the predetermined position by the horizontal movement of the temporary assembly 10 in the approaching direction.

For example, it is simple to characterize a specific portion of the holding portion 36 when the lock nut 9 comes into the screwing start position where the lock nut 9 comes into contact with the tip of the upper end extension portion 8 of the tie rod fuel rod 2 and detect this characteristic portion. is there. As a detection method, a method using a distance measuring device using an optical sensor may be used. That is, the stepped portion 36 of the holding portion 36 on the threaded rod 35 side
Since the distance from the position detector 38 to the side surface of the holding unit 36 changes at x, if the position detector 38 is installed vertically above the stepped portion 36x when the holding unit 36 reaches the screwing start position, horizontal With the movement, the sensor 36
The distance to the side surface was measured over time, and the step 3
If a change in the measured value is detected at 6x, it can be determined that the holding portion 36 and the lock nut 9 have reached the screwing start position.

In the present embodiment, from the time when the holding portion 36 reaches the screwing start position, at least the stroke for the lock nut 9 to advance the upper end extension portion 8 of the tie rod fuel rod 2 toward the assembly table 40 by screwing. Is moved horizontally further. Thereby, the holding portion 36
The spring mechanism 37 in the threaded rod 35 contracts in a position where the lock nut 9 is in contact with the tip end of the upper end extension 8 of the tie rod fuel rod 2 to generate an urging force that becomes a propulsive force necessary for subsequent screwing. .

The position detector 38 is also used for confirming the completion of screwing. In the present embodiment, a depression 36y is formed at a position of the screwing rod 35 which comes to a position immediately below the position detector 38 when the predetermined screwing is completed, and the lock nut 9 is formed when the position detector 38 detects the depression 36y. Is determined to be completed.

In the present embodiment, the screwing device 32
In addition, a rotation detector 39 was installed separately from the position detector 38 as a detector for confirming completion of screwing. The rotation detector 39 determines the number of rotations of the lock nut 9 required for screwing in advance from the thread pitch of the upper end extension portion 8 of the tie rod fuel rod 2 and the stroke of the screwing movement. Monitor the rotation of
If the predetermined number of rotations can be detected, it is determined that the screwing of the lock nut 9 has been completed. By confirming screwing by such a detector, screwing failure due to biting of the lock nut 9 can also be detected.

The operation of screwing the lock nut 9 by the screwing device 32 of the assembling apparatus having the above-described configuration proceeds as shown in FIG. Here, for simplicity of explanation,
The operation by a set of screwing operation units will be described.

First, the lock nut 9 is attached to each holding portion 36 in advance.
And the temporary assembly 1 together with the upper tie plate 6
Positioning is performed in a plane orthogonal to the center axis of zero. Next, by moving the upper handling device 30 close to the temporary assembly 10, the tips of the fuel rods exposed on one end side of the temporary assembly 10 are fitted into the through socket holes 7, and the upper tie plate 6 is fitted. . When the insertion of the tips of all the fuel rods into the through socket holes 7 is completed, the upper end extensions 8 of the tie rod fuel rods 2 pass through the through socket holes 7 and protrude from the upper surface of the upper tie plate 6.

Therefore, while the position detector 38 is operated while the holding state of the upper tie plate 6 by the upper fixing member attaching device 31 is maintained, the screwing device 32 is attached to the temporary assembly 10 by a driving mechanism (not shown). It is horizontally moved in a direction approaching the same (FIG. 4A). This movement causes the holding portion 36 holding the lock nut 9 to approach the tip of the tie rod fuel rod 2, but moves until the position detector 38 detects that the holding portion 36 has reached the predetermined screwing start position as described above. to continue.

When it is confirmed that the holding portion 36 has reached the screwing start position, the screwing device 32 is further advanced at least by a distance corresponding to a stroke necessary for actual screwing. Thereby, the spring mechanism 3 in the screw-in rod 35
7 is contracted, and the urging force of the restoring force of the spring mechanism 27 acts on the holding portion 36 in the screwing direction (FIG. 4B).

As described above, the torque motor 33 is driven in a state where the holding portion 36 has obtained the urging force in the screwing direction at the screwing start position. The rotational movement of the torque motor 33 is transmitted to a threaded rod 35 via a joint part 34 connected to the motor rotating shaft, the holding part 36 starts rotating in the screwing direction, and the lock nut 9 moves with the tie rod fuel. The rod 2 is screwed into the thread of the upper end extension 8. The screwing of the lock nut 9 is advanced by the rotational force and the propulsive force of the urging force of the spring mechanism 37 (FIG. 4C).

The progress of the screwing is monitored by the position detector 38 and the rotation detector 39, and by the detection of the position detector 38, it is confirmed that the holding unit 36 has reached the screwing completion position, and the rotation detector 39 By threaded rod 3
Confirm that 5 has rotated the number of turns required for screwing.

When it is confirmed by these detectors that the screwing of the lock nut 9 into the tie rod fuel rod 2 is completed, the driving of the torque motor 33 is stopped and the screwing device 32 is moved horizontally in a direction away from the temporary assembly 10. . With this movement, the holding portion 36 also releases the lock nut 9 and retreats from the upper end extension portion 8 of the tie rod fuel rod 2. Further, by retreating the entire upper handling device 30, the fixing of the upper tie plate 6 to the temporary assembly 10 is completed.

In the assembly of the fuel assembly for BWR, the provision of the upper tie plate 6 on the upper end of the temporary assembly 10 as described above is performed by the lower handling device 50. It is more convenient to carry out the process after the attachment to the lower end is completed. This is the lower tie plate 5
Is fixed to the temporary assembly 10 by screwing the male screwed lower end of the tie rod fuel rod 2 into the female screwed through socket hole of the lower tie plate 5.

That is, in the lower handling device 50, only the tie rod fuel rods 2 are clamped separately from the standard fuel rods 2 in which the lower ends are simply inserted into the through socket holes of the lower tie plate 5 in a bottomed state. Must be fitted into the through socket hole while rotating the shaft, but if the upper end of the tie rod fuel rod 2 is not fixed, the tie rod fuel rod 2 itself can be easily screwed in and fixed at the lower end side. This is because the screwing operation of the lock nut 9 on the upper end side can be stably performed if it is performed.

Therefore, the lower handling device 50 of the present assembling apparatus does not require the screwing device 32 for screwing the screws and nuts, unlike the upper handling device 30, and the lower fixing member mounting device 51 is provided with the tie rod fuel rod 2 What is necessary is just to provide the mechanism for screwing in.

Next, a fuel assembly assembling apparatus according to another embodiment of the present invention will be described below together with the illustrated embodiment, taking as an example the assembly of a PWR fuel assembly. FIG. 5 is a schematic configuration diagram of a lower handling device of the fuel assembly assembling apparatus of the present embodiment. FIG. 6A is a partial view showing a configuration of one set of a screwing operation unit, and FIG. FIG. 7 is a partially enlarged view illustrating a configuration of a holding unit of the operation unit, and FIG. 7 is an explanatory diagram illustrating a process of a screwing operation by the screwing device of the present embodiment.

In the present embodiment, as shown in the side sectional view of FIG. 9, 24 control rod guide thimble tubes 12 are provided at some cell positions in a plurality of support grids 14 to be arranged at intervals.
And 264 fuel rods, and one in-core instrumentation thimble tube 13 in the center with 264 fuel rods inserted in a 17 × 17 square lattice array of skeletons constructed by arranging and joining. For the assembly 20, the lower end of each thimble tube 12 is fitted into the through-hole 17 of the lower nozzle 16, and the thimble screw thread is inserted through the through-hole 17 into the lower tube end 18 of the control rod guide thimble 12. A description will be given of an assembling apparatus intended to complete the fixing of the lower nozzle 16 to the temporary assembly 20 by screwing the 19.

As an assembling apparatus for mounting the upper nozzle 15 and the lower nozzle 16 which are end fixing members to the PWR temporary assembly 20, mainly the PW
An assembling table 40 for fixing and holding the R temporary assembly 20 sideways so that the axis of the R temporary assembly 20 is substantially horizontal, and upper handling units arranged on both sides of the assembling table 40 in the direction in which the axis of the assembling table 40 extends. It comprises a device 30 and a lower handling device 50.

However, the upper handling device 30 is provided with an upper fixing member attaching device 31 having a unique structure for attaching the upper nozzle 15, and the lower handling device 50 is equipped with a unique structure for attaching the lower nozzle 16. The lower fixing member mounting device 51 provided with

As shown in FIG. 5, the lower handling device 50 supports the lower nozzle 16 at the tip end facing the assembling table 40, moves close to the temporary assembly 20, and moves to the one end side of the temporary assembly 20. A lower fixing member mounting device 51 for fitting the exposed lower end of each thimble pipe (12, 13) into each through socket hole 17 of the lower nozzle 16 while guiding the lower end of the thimble pipe (12, 13) with a guide means (not shown); , 13) A screwing device 52 for screwing the thimble screw 19 into the lower end 18 of the control rod guide thimble tube 12 after the lower end is fitted into the through socket hole 17 is provided.

The close movement of the lower fixing member mounting device 51 to the temporary assembly 20 for mounting the lower nozzle 16 (fitting the lower end of the thimble tube into the through socket hole) involves horizontally moving the entire lower handling device 50. In order to start the screwing operation, the screwing device 52 is installed on the support table T which moves independently and horizontally in the lower handling device 50 by a dedicated driving mechanism (not shown). The approach movement and the separation movement after the screwing operation can be easily controlled as a separate step from the fitting operation of the lower nozzle 16.

The screwing device 52 rotates the thimble screw 19 from the bottom side of the through-hole 17 into the lower end 18 of the control rod guide thimble tube 12 fitted in the through-hole 17 of the lower nozzle 16. A screwing operation is performed by pushing it into the temporary assembly 10 while the torque motor 5 is used as a rotating mechanism for giving a screwing rotary motion as shown in FIGS. 5 and 6A.
3 and is configured to transmit the rotational motion of the torque motor 53 to the screwing rod 55 whose distal end serves as the holding portion 56 of the thimble screw 19 via the joint 54.

Also, in the screwing device 52 of the present embodiment, the spring mechanism 57 is incorporated in the screwing rod 55 so as to be able to expand and contract in the horizontal direction. It can be used as a driving force for screwing the screw 19.

In the present embodiment, the holding section 56
As shown in FIG. 6 (b), a driver structure is provided in which the tip of the thimble screw 19 is inserted into the head of the thimble screw 19 and the thimble screw 19 can be locked and supported so that the rotational movement from the screw rod 56 can be transmitted. And The structure of the holding portion 56 not only can maintain a sufficient holding force so that the thimble screw screw 19 does not come off and fall down due to vibration when moving close to the temporary assembly 20 or the like. Hold the holding portion 56 to the temporary assembly 2
The driver structure can be easily separated from the head of the thimble screw screw 19 by simply retreating in the direction away from 0.

In the present embodiment, the joint portion 54, the threaded rod 55,
Twenty-four sets of screwing operation parts up to the holding part 56 are provided for the number of the control rod guide thimble pipes 12 into which the thimble screw screws 19 are to be screwed, and at the same time, the thimble screw into the lower pipe end 18 of all the control rod guide thimble pipes 12 is provided. Screw 19
Can be screwed in.

The screwing operation of the thimble screw 19 by the screwing device 52 of the assembling apparatus having the above-described structure proceeds as shown in FIG. Here, for the sake of simplicity of explanation, an operation by a set of screwing operation units will be described.

First, the thimble screw screw 19 is inserted into each holding portion 56 from the head in advance to be in a support state, and the lower nozzle 16 is aligned with the temporary assembly 20 in a plane perpendicular to the central axis. . Next, the lower handling device 5
0 to the temporary assembly 20, the temporary assembly 20
The lower nozzle 16 is fitted by fitting the lower end of each thimble tube (12, 13) exposed to the other end of the lower nozzle 16. The fitting of all the thimble tubes into the through socket hole 17 is completed. At this time, the lower end 18 of the control rod guide thimble tube 12 is connected to the lower nozzle 1 through the through-hole 17.
6 is exposed on the bottom side.

Therefore, while the holding state of the lower nozzle 16 by the lower fixing member attaching device 51 is maintained, the screwing device 52 is moved together with the support table T in a direction approaching the temporary assembly 20 by a drive mechanism (not shown). Move horizontally. With this movement, the holding portion 56 approaches the bottom surface of the lower nozzle 16, and the thimble screw 19 is inserted into the through-hole 17 in which the lower end of the control rod guide thimble tube 12 is fitted from the bottom surface side to the upper surface side of the lower nozzle 16. Then, the tip of the thimble screw 19 reaches the lower pipe end 18 of the control rod guide thimble pipe 12 (FIG. 7A).

The insertion of the tip of the thimble screw 19 is advanced, and the male thread portion is inserted into the control rod guide thimble tube 12.
When the screw thread 19 is caught in the internal thread in the lower pipe end 18, further horizontal movement of the screw screw 19 is restricted, but this is set as the screwing start position, and the screw screw 19 is further moved at least by the distance required for the actual screwing. Screwing device 52
To move forward. As a result, the spring mechanism 27 of the threaded rod 55 contracts, and the urging force of the restoring force of the spring mechanism 57 acts on the holding portion 56 in the screwing direction.

When the torque motor 53 is driven in the state where the holding portion 56 has obtained the urging force in the screwing direction at the screwing start position, the rotational motion of the torque motor 53 is controlled by the joint connected to the motor rotating shaft. Is transmitted to the threaded rod 55 via the portion 54, the holding portion 56 starts to rotate in the screwing direction, and accordingly, the thimble screw 19 is screwed into the thread in the lower pipe end 18 of the control rod guide thimble tube 12. I will do it. The screwing of the screw screw 19 is advanced by the rotational force and the propulsive force of the urging force of the spring mechanism 57 (FIG. 7B).

The progress of the screwing is monitored by a detecting means such as a rotation detector (not shown) which can confirm that the screwing rod 55 has rotated by the number of rotations required for screwing.
Check that the screwing has been completed.

When the completion of the screwing of the thimble screw 19 into the lower end 18 of the control rod guide thimble tube 12 is confirmed, the driving of the torque motor 53 is stopped and the screwing device 52 is temporarily moved by the support table T. It is horizontally moved in a direction away from the assembly 20 (FIG. 7).
(C)). With this movement, the driver-like chuck portion separates from the head of the screw screw 19 and separates therefrom.
6 retreats. Further, if the entire lower handling device 50 is retracted, the fixing of the upper tie plate 6 to the temporary assembly 20 is completed.

In assembling the PWR fuel assembly, the lower nosle 19 is attached to the lower end of the temporary assembly 20 as described above by the upper handling device 30 using the upper nozzle 15.
It is more convenient to complete the mounting after the temporary assembly 20 is attached to the upper end. This is the temporary assembly 2 of the upper nozzle 15
This is because fixing to zero is performed by welding and fixing after fitting the upper end of the control rod guide thimble tube 19 into the through socket hole of the upper nozzle 15. That is, after the mounting of the upper nozzle 15 is completed, the control rod guide thimble pipe 19 is fixed at the upper end, and the screwing work at the lower pipe end 18 can be performed in a stable state.

As shown in the above embodiments, the screwing device for mounting the upper tie plate by the upper handling device when assembling the BWR fuel assembly, and the lowering device by the lower handling device when assembling the PWR fuel assembly. The screwing device for mounting the nozzle can be of a common configuration except for the configuration of the holding portion. Therefore, as the screwing device, the holding portion can be replaced with a device corresponding to the target screw / nut. With this configuration, the device design is simple.For example, in addition to the case shown in the above embodiment, a screw for a ring nut or a guide for temporary screwing into a tip when a thimble tube is inserted into a support lattice. It can be used for various screwing operations such as removal of thimble tube cap and temporary screwing of thimble tube.

[0076]

As described above, according to the fuel assembly assembling apparatus of the present invention, the screwing operation of various screws and nuts can be automated, and the ends of the fuel assembly for a light water reactor with respect to both ends of the temporary assembly. There is an effect that the automation of the mounting operation of the part fixing member is made more complete, the exposure of the worker is reduced, and the assembly speed of the fuel assembly can be secured at a constant level.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an entire assembly apparatus for a BWR fuel assembly as a fuel assembly assembly apparatus according to an embodiment of the present invention.

FIG. 2 is a partial side view illustrating a schematic configuration of an upper handling device and a screwing device of the fuel assembly assembly device of FIG. 1;

FIG. 3 is a partially enlarged view illustrating a configuration of a holding unit of the screwing device of FIG. 2;

4A to 4C are explanatory diagrams showing a screwing operation by the screwing device in FIG. 2, and FIGS. 4A to 4C are partial schematic views in respective operation processes.

FIG. 5 is a partial side view illustrating a schematic configuration of a lower handling device of a fuel assembly assembly for PWR as a fuel assembly assembly device according to another embodiment of the present invention.

6 is a schematic configuration diagram of the screwing device of FIG. 5,
FIG. 3A is a partially enlarged view illustrating a configuration of one set of a screwing operation unit, and FIG. 3B is a partially enlarged view illustrating a configuration of a holding unit.

FIGS. 7A to 7C are explanatory diagrams showing a screwing operation by the screwing device of FIG. 6, and FIGS. 7A to 7C are partial schematic views in respective operation processes.

FIG. 8 is a schematic side sectional view illustrating a configuration of a general BWR fuel assembly.

FIG. 9 is a schematic side sectional view illustrating the configuration of a general PWR fuel assembly.

[Explanation of symbols]

 1: BWR standard fuel rod 2: Tie rod fuel rod 3: Water channel 4: Spacer 5: Lower tie plate 6: Upper tie plate 7: Through-hole socket 8: Upper end extension (of tie rod fuel rod) 9: Lock nut 10: BWR temporary assembly 11: PWR fuel rod 12: control rod guide thimble tube 13: furnace guide instrumentation thimble tube 14: support grid 15: upper nozzle 16: lower nozzle 17: through socket hole 18: (control rod guide thimble tube Lower tube end 19: thimble screw screw 20: PWR temporary assembly 21: guide means 22: ball plunger 30: upper handling device 31: upper fixing member mounting device 32, 52: screwing device 33, 53: torque motor 34, 54: Joint part 35, 55: Threaded rod 36, 56: Holding part 36x: Holding part step Part 36y: recess 37, 57: spring mechanism 38: the position detector 39: rotation detector 40: assembling table 50: lower handling device 51: lower fixing member mounting device T: screwing device support table

Claims (2)

[Claims] 1. A fuel assembly for a light water reactor for attaching upper and lower end fixing members having a unique structure to upper and lower ends of a temporary assembly in which a plurality of fuel rods are held in a square lattice arrangement at substantially parallel intervals. An automatic assembling apparatus for a body, comprising: an assembling table for fixedly holding the temporary assembly in a sideways state so that its axis is substantially horizontal; and ,
Holding the upper end fixing member to be mounted on one end side corresponding to the upper end of the temporary assembly, fit the end of the fixing target element exposed at one end of the temporary assembly into the through socket hole of the upper end fixing member. An upper handling device for causing the assembly table to be aligned with the assembly table in the direction in which the axis extends.
Holding the lower end fixing member to be attached to the other end corresponding to the lower end of the temporary assembly, and holding the end of the fixing target element exposed at the other end of the temporary assembly to the through socket hole of the lower end fixing member. A lower handling device for fitting, wherein the fitting of the end of the fixing target element is performed by screwing and fixing screws and nuts to the tip protruding from the fixing member through the corresponding through socket hole. When including the one to be completed, the upper handling device and the lower handling device each include a screwing device for screwing screws and nuts to the tip of the element to be fixed on the opposite side of the temporary assembly of the holding member to be held. A fuel assembly assembly device, comprising: 2. The screwing device according to claim 1, further comprising: a holding unit that holds the screws and nuts in a releasable manner toward a tip end of the fixing target element to be screwed in; and the screwing unit is screwed around the central axis of the fixing target element. A rotation mechanism for rotating in the direction, and a drive mechanism for horizontally moving at least the holding unit and the rotation mechanism so as to be able to approach and separate from the temporary assembly,
As the holding mechanism holding the screws and nuts is screwed in by the rotation mechanism and rotated by the drive mechanism, the holding mechanism is horizontally moved in the direction of approaching the temporary assembly, thereby supporting the screws and nuts. The fuel assembly assembling apparatus according to claim 1, wherein the fuel assembly is screwed into a tip end of the fixing target element to be fixed.