JPH0228593A - Fitting device for lower nozzle - Google Patents

Abstract

PURPOSE:To make lower nozzle fitting operation unmanned and to reduce the possibility of exposure in the operation more by providing a pressing and fixing mechanism which presses an insertion guide plate against a lower support base. CONSTITUTION:The lower support base 5 having an opening part which is large enough to pass the insertion guide plate 7 and a lower nozzle N is provided below a lower nozzle fixation position. Then the pressing and fixing mechanism (pressing cylinder 30) which can press the insertion guide plate 7 against the lower support base 5 is added movably between the pressing position of the guide plate 7 and a position behind the opening part. Further, a carrying mechanism 40 is provided which displaces a holding mechanism 47 for conveyance capable of engaging both the fixation hole of the lower nozzle N and an engagement hole formed in the guide plate 7 selectively to the position where it can engage only either of the fixation hole and engagement hole. Consequently, the lower nozzle fitting operation is made unmanned and the possibility of exposure in the operation is reduced more.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a guide plate used in assembling a control rod guide tube, etc., which is inserted and fixed through a plurality of support grids arranged on an assembly jig. This invention relates to a lower nozzle mounting device for automatically fixing the lower nozzle to the lower end of each control rod guide tube.

"Prior Art" Conventionally, the above-mentioned fuel assembly has been assembled in the following manner.

First, a plurality of support grids are placed parallel to each other at regular intervals on an elongated rectangular fuel assembly assembly jig, and a guide plate is placed at a position below the lowest support grid. This guide plate has a large number of guide holes formed in correspondence with each grid space of the support grid, and through these guide holes, the fuel rods are inserted and fixed into predetermined grid spaces by a fuel rod insertion device. .

Next, the worker manually removes the guide plate from the assembly jig, applies the lower nozzle to the lower end of the control rod guide tube, positions it, and then passes the lower nozzle through the hole in the control rod guide tube to the lower end of the control rod guide tube. A screw was screwed into the threaded hole in the stopper to secure the lower nozzle.

``Problem to be Solved by the Invention'' However, the above-mentioned manual method has the problem that it takes time and effort to assemble the fuel assembly, and the work efficiency is low. In addition, in order to sufficiently meet safety standards that are expected to further increase in the future, it is desired to make the lower nozzle installation work unmanned and to further reduce the possibility of exposure to radiation during the work.

Therefore, it is conceivable that the guide plate and the lower nozzle are sandwiched between a pair of locking arms, etc., to transport and hold them down. The relative position of the conveyed object and the arm had to be maintained accurately. In addition, since the guide plate is larger than the lower nozzle, it is difficult to convey them using the same locking claw, and it is necessary to convey the lower nozzle and the guide plate using separate conveyance mechanisms. This has led to the problem that the configuration of the device has become complicated and the equipment cost has increased.

"Means for Solving the Problems" The present invention has been made to solve the above problems, and includes a lower support base having an opening large enough to allow the insertion guide plate and the lower nozzle to pass through, at the lower nozzle fixing position. a pressing fixing mechanism capable of pressing the insertion guide plate etc. is attached to the lower support base so as to be movable between a position where the guide plate etc. is pressed and a position evacuated from the opening; A conveying holding mechanism capable of engaging with either the fixing hole of the nozzle or the engagement hole formed in the guide plate is selectively placed in a position where it can engage only with either the fixing hole or the engagement hole. It is characterized by comprising a conveying mechanism for displacing the object.

Embodiment FIG. 1 is a plan view showing a fuel assembly assembly system equipped with an embodiment of the lower nozzle attachment device according to the present invention. For convenience of explanation, the left side in Figure 1 is the front side,
The right side is called the rear side.

Reference numeral l in the figure is a rectangular fuel assembly assembly jig.
..., a lower nozzle fixing frame 4 and a lower support stand 5 are provided.

The support grid fixing frames 3 are used to fix support grids, respectively, and are similar to conventional devices.

As shown in FIG. 2 (longitudinal cross-sectional view) and FIG. 3 (right side view), the lower nozzle fixing frame 4 has an upwardly open U-shape that accommodates the lower nozzle N in a horizontally erected state. and
A reference face plate 6 for positioning the housed lower nozzle N is fixed to the lower surface and one side surface of the inner surface, respectively. Further, on the rear surface of the lower nozzle fixing frame 4, there is formed a stepped portion 8 (see FIG. 9) into which the guide plate 7 (see FIG. 6) or the screw holder (51) is fitted.

Further, the lower nozzle fixing frame 4 has nozzle fixing mechanisms 9, 9 for pressing the lower nozzle N against the two reference face plates 6 when screwing the lower nozzle N into the control rod guide tube.
is installed. These nozzle fixing mechanisms 9 consist of a cylinder 10 attached to the nozzle fixing frame 4 as shown in FIG. Arm 12 and this arm 1
When the rod of the cylinder 10.10 is retracted, the arm 12.12 connects to the lower nozzle N.
When the rod is pressed down and brought into contact with the positioning plate 6.6 (as shown), and the rod is pushed out, the arm 12.12 rotates to release the lower nozzle N. Further, a nozzle fixing mechanism (only the mounting position is shown) 14 similar to the above is provided on the rear surface of the nozzle fixing frame 4, and is configured to press the lower nozzle N against the lower end of the control rod guide tube. .

On the other hand, as shown in FIG. 4, a plurality of screws 20 are passed through the guide plate 7 in a forward direction at locations corresponding to the control rod guide tubes, and these screws 20 are covered on the front side of the guide plate 7. A support cylinder 22 housing a spring 21 is fixed in this manner. and each screw 2
0 is urged in the backward direction by a spring 21.

Next, the lower support stand 5 has an opening 23 large enough for the guide plate 7 to pass through, as shown in FIG. 24
...is formed horizontally.

Further, on the front side of the lower support stand 5, a pair of press support plates 25 are provided.
are arranged vertically, and sliding bearings 26.26 at both ends of these suppression support plates 25 are connected to the sliding shaft 24.2.
4 so as to be horizontally slidable. Furthermore, opening/closing cylinders 2 are provided at the upper and lower parts of the lower support base 5 in opposite directions.
7.27 are fixed horizontally, and the rod tips of these opening/closing cylinders 27 are respectively fixed to the pressure support plates 25, and the pressure support plates 25.25 approach on both sides along the sliding shafts 24... They are now separated.

Also, in the vicinity of the rod passage position, there is a stop pin 29 that stops the pressing support plate 25 at the position where the guide plate 7 is pushed (the opening in the figure).
is buried in the lower support base 5.

On the other hand, a pressing cylinder 30 is fixed to the rear surface of the central portion of each pressing support plate 25 so as to face forward, as shown in FIG.

The negative ends of arms 31 are connected upwardly and downwardly to the rod tips of these cylinders 30, and the other ends of these arms 31 are connected to a pair of arms 31 with one end tiltably attached to the press support plate 25. is connected to the other end of the tilting plate 32. Further, a press plate 33 is attached to the support plate 25 so as to face forward while being biased rearward by a spring (as shown).

A pressing plate 33 is fixed to each of these tilting plates 32 toward the front side. As a result, each pressing cylinder 30
When the rod is moved forward, the arm 31.
When the rod 2.32 is pushed open, the pressure plate 33.33 is moved back, and when the rod is moved backward, the tilting plate 32.32 is closed and the pressure plate 33.33 is moved forward.

On the other hand, at the rear of the fuel assembly assembly jig 1, a linear conveyance device 40, such as a linear motor type, is installed perpendicularly thereto. This transport device 40 has two transport tables 41 and 42.
, and these can be operated individually on opposite sides.

A two-axis NC drive machine 44 equipped with a horizontal main shaft 43 facing in the front-rear direction is installed on one of the conveyor tables 41.
The main shaft 43 is moved back and forth and rotated around the axis.

An elongated mounting member 45 is fixed in a T-shape to the front end of the main shaft 43, and a television camera 46 is embedded through the center of the mounting member 45.

Furthermore, conveyance holding mechanisms 47 are attached to both ends of the attachment member 45, respectively.

As shown in FIG. 6 and FIG.
A flexible cylindrical ring 49 made of urethane rubber or the like is passed through the tips of these rods 48A, and a cap 5 with a round tip is attached to the tip of the rod 48A.
0 is attached, and when the rod 48A is retreated,
When the cap 50 is retracted, the ring 49 is crushed in the axial direction between it and the mounting member 45, and is expanded evenly in the radial direction.

On the other hand, in front of the conveyance table 41, along the conveyance device 40,
A mounting table 52 is provided on which the guide plate 7 and the lower nozzle N1 screw holder 51 can be placed, respectively.

As shown in FIGS. 8 and 9, the screw holder 51 has the same external shape as the guide plate 7, and has a pair of holding holes 53 formed in the same locations as the guide plate 7, while the legs of the lower nozzle N Holes 54, into which the lower ends of the legs K, are fitted, are formed at locations corresponding to the legs K, respectively.

Furthermore, a screw storage cylinder 55 is vertically penetrated and fixed to the screw holder 51 in correspondence with the control rod guide pipe connection hole (as shown) of the lower nozzle N. As shown in FIG. 8, a hexagonal wrench 56 is housed inside each of these storage cylinders 55 facing forward, and the hexagonal wrench 56 is biased backward by a spring 58 via a stopper 57. At the front end of the housing *55, one screw 59 with a hexagonal hole for fixing the nozzle is housed facing forward. Note that the reference numeral 60 in the figure indicates the position pressed by the pressing plates 33 of the lower support base 5.

On the other hand, a screw tightening/crimping mechanism 66 is installed on the other conveyance table 42 via an NC lifting/lowering drive machine 65. This mechanism 66 includes an automatic screw fastener 67, an automatic caulking tool 68, and a television camera 69. The automatic screw tightener 67 operates the driver 70 to move back and forth and rotate based on the signal from the control panel (the path shown in the figure), while the automatic screw tightener 68 controls the tightened screw etc. based on the instructions from the control panel. Tighten and secure.

Further, at a position opposite to the fuel assembly assembly jig 1 with the conveyance device 40 in between, there is a fuel rod etc. retracting and loading device (a path shown in the figure).
is provided. This device is the same as the conventional product, and the extraction rod that engages the rear end of the fuel rod is passed through a guide plate 7 and a support grid for aligning the axis of the extraction rod.
After extending the fuel rods to the fuel rod magazine rack (path shown in the figure) arranged on the front side of the assembly jig 1 and connecting them to fuel rods, etc. therein, the pulling rods are retreated to be inserted into each grid space of the support grid. It is configured to sequentially load fuel rods, etc.

Next, a method of using the above-mentioned lower nozzle mounting device will be explained in order.

It is now assumed that fuel rods have been loaded into each support grid using the fuel rod retracting and loading device. At this point, the guide plate 7 is arranged on the rear surface of the lower nozzle fixing frame 4, and the guide plate 7 is fixed to the control rod guide tube with a screw, and the press support plates 25 and 25 of the lower support stand 5 are mutually connected. The guide plate 7 is pressed from behind at the position A in FIG.

In order to attach the lower nozzle N from this state, the carrier 42 is moved to the rear of the lower support stand j, and the automatic screw tightener 67 is activated to fix the guide plate 7 to the control rod guide tube. Loosen the screws 20 one after another and return to the transport platform 4.
Return 2 to its original position.

Then, the conveyance table 41 is moved to the rear of the lower support stand 5, and the cap 50 and ring 4 of the conveyance holding mechanism 47.47 are moved.
9 into the holding hole 7A of the guide plate 7, and then
8 to inflate the ring 49 in the radial direction and fix the inner surface of the holding hole 7A.

Next, each pressure cylinder 30 of the lower support stand 5 is activated,
The pressing plates 33... are moved back to release the guide plate 7, and the pressing support plates 25 and 25 are retracted from the opening 23,
Then, the main shaft 43 of the two-axis NC drive machine 44 is moved back, and the guide plate 7 fixed by the conveyance holder is removed t4, and the guide plate of the mounting table 52 is removed. Placement position 52A
Then, the guide plate 7 is placed on top of the guide plate 7 and released.

Furthermore, the conveyance platform 41 is moved to the lower nozzle mounting position 52B, and the main shaft 43 is rotated and advanced to move each conveyance holding mechanism 47 to the 1 formed on the lower surface of the leg K... of the lower nozzle N.
It is inserted into the pair of holes KA, the lower nozzle N is locked in the same manner as described above, and the lower nozzle N is carried to the rear of the lower support stand 5.

Next, the lower nozzle N is pushed into the lower nozzle fixing frame 4 through the opening 23 of the lower support base 5, and the nozzle fixing mechanisms 9, 9, 14, etc. of the nozzle fixing frame 4 are activated, and the lower nozzle N is pressed against the lower end of the control rod guide tube and the reference face plates 6, 6 to position the lower nozzle N.

Next, the transport holding mechanism 47.47 is extracted from the lower nozzle N, the transport table 41 is moved, the screw holder 51 is carried from the mounting table 52, and the screw holder 51 is passed through the opening 23 of the lower support table 5 to the step of the lower nozzle fixing frame 4. 8, and in this state move the pressing support plate 25.25 to the guide plate pressing position A, and actuate the pressing cylinder 30.30 to press the pressing plate 3.
3. Attach the screw holder 51 to the lower nozzle fixing frame 4.
to press against.

Next, the conveyance table 41 is evacuated, and the conveyance table 42 is moved to the rear of the lower support stand 5.1. Insert the automatic screw tightener 67 into the screw storage cylinder 55 of the screw holder 51, rotate the internal hexagonal wrench 56, and tighten the screw 59 loosely at first to the lower end of the control rod guide tube through the connecting hole of the lower nozzle N. It's crowded.

This operation is repeated in sequence to temporarily secure all control rod guide tubes and lower nozzles N.

Then, operate the automatic screw tightener 67 again and tighten each screw 59 that connects the lower nozzle N and the control rod guide tube one after another to the specified torque, completing the process for all screws 59... let

Next, release the fixation of the screw holder 51 by the lower support stand S, and remove the screw holder 51! When returned to position 52C, each screw 59 is tightened by automatic tightening tool 68.
is crimped and fixed to the lower nozzle N, and the conveyor table 42 is returned to its original position.

According to the lower nozzle mounting device having the above configuration, the lower nozzle mounting work, which was conventionally done manually, can be
C control allows unmanned operation, significantly improving work efficiency and eliminating the risk of exposure to radiation.

Furthermore, the transport holding mechanism 47 of this device has a structure in which the holding holes of each member are locked from the inner surface by compressing and expanding the diameter of the ring 49.
A holding mechanism including the main shaft 43, a holding hole 53 of the guide plate 7,
Hole KA of the lower nozzle and holding hole 5 of the screw holder 51
The positioning accuracy with 3 may be rough, and the lower nozzle N
There are no locking scratches on the body, and the configuration is simple.

In addition, this conveyance holding mechanism 47 can fix three parts, the guide plate 7 with holding holes in different positions, and the lower nozzle N1 screw holder 51 by rotating the main shaft 47. The configuration can also be simplified.

Furthermore, with this device, one screw is passed through the opening 23 of the lower support stand 5, and then the guide plate 7, the lower nozzle N1 screw holder 5
1 can be conveyed, and the press support plate 25.25 is provided so as to be retractable from this opening 23, so the operating speed is faster and the configuration can be simplified compared to a configuration in which the entire press fixing mechanism is retracted. This has the advantage that less energy is required for operation.

Note that the present invention is not limited to the above-mentioned embodiments, and the configuration of each part may be changed.

"Effects of the Invention" As explained above, according to the lower nozzle mounting device of the present invention, the lower nozzle mounting work, which was conventionally done manually, can be automated by NC control etc., improving work efficiency. Not only can this be greatly improved, but also the risk of exposure to radiation can be eliminated.

In addition, the conveyance holding mechanism of this device is configured to engage with the inner surface of the fixing hole of the lower nozzle or the engagement hole of the guide plate, so compared to a configuration in which these are sandwiched with, for example, a locking claw, the mechanism of the conveyance holding mechanism of the guide plate is The positioning accuracy between the holding hole and the hole of the lower nozzle may be rough, and when the lower nozzle is locked, no locking damage is caused to the tap in the hole. Furthermore, the one-feed mechanism displaces the conveyance holding mechanism and selectively fixes the guide plate and the lower nozzle with different hole positions to be engaged, so only one type of conveyance holding mechanism is required. The configuration can be simplified and equipment costs can be reduced.

Furthermore, in this device, the guide plate and the lower nozzle can be transported through the opening of the lower support base, and the press fixing mechanism is retractable from this opening, so compared to a configuration in which the entire press fixing mechanism is retracted. The advantages of this are that the operating speed is high, the configuration can be simplified, and the energy required for operation is small.

[Brief explanation of the drawing]

Fig. 1 is an overall plan view of the lower nozzle mounting device according to the present invention, Figs. 2UgJ and 3 are longitudinal sectional views and side views showing the press fixing mechanism of the device, and Fig. 4 is a guide plate and a screen λ. FIG. 5 is a side view of the pressure fixing mechanism; FIGS. 6 and 7 are side views and partially cutaway front views showing the operation of the transport holding mechanism; FIGS. FIG. 9 is a plan view and a front view showing the screw holder. N...lower nozzle, K...lower nozzle leg, KA
...Leg holes, 1.Fuel assembly assembly jig, 3.
・・Support grid fixing frame, 4・Lower nozzle fixing frame, 5・
...Lower support stand, 7...Insertion guide plate, 9.14.
... Nozzle fixing mechanism, 23... Opening of lower support base, 25... Pressing support plate, 30... Pressing cylinder (suppression fixing mechanism) 33...
Pressing plate (pressing fixing mechanism), 40... Straight transport device, 41, 42... Transport platform, 43... Main shaft, 47...
1 holding structure for transportation, 51... screw holder, 52... mounting table, 59
... 4 screws with hexagonal holes, 66 ... Screw tightening / force 9 tightening mechanism, 67 ... Automatic screw tightener, 68 ... Automatic tightening tool.

Claims (1)

[Claims] A plurality of support grids are arranged in parallel at intervals on a fuel assembly assembly jig, and an insertion guide plate is arranged on the lower nozzle fixed side of these support grids, and this insertion guide plate After sequentially inserting the fuel rods into the grid spaces of the support grid, the insertion guide plate is removed from the assembly jig, and a lower nozzle is fixed to the lower end of each control rod guide tube supported by the support grid. The lower nozzle mounting device includes a lower support having an opening large enough to allow the insertion guide plate and the lower nozzle to pass through, and is provided below the lower nozzle fixing position, and the insertion guide plate is attached to the lower support. A pressing fixing mechanism capable of pressing the guide plate, etc. is provided so as to be movable between a pressing position of the guide plate, etc. and a position retracted from the opening, and a fixing hole of the lower nozzle or an engagement hole formed in the guide plate. A lower part characterized by comprising a conveyance mechanism that selectively displaces a conveyance holding mechanism that can engage either of the fixing hole or the engagement hole to a position that can engage only either the fixing hole or the engagement hole. Nozzle mounting device.