JPH0364826B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an apparatus for visual inspection of nuclear fuel pellets formed in a cylindrical shape.

``Prior art'' For example, nuclear fuel pellets for light water-cooled nuclear reactors are produced by molding low-enrichment uranium dioxide powder in a mold to form cylindrical green pellets (also called compacts). Green pellets are sintered at high temperatures to produce dense sintered pellets, and the outer diameter of the sintered pellets is polished to improve dimensional accuracy, which is used as nuclear fuel pellets by filling them into fuel cladding tubes. The fuel pellets are cylindrical bodies with an outer diameter of 9 mm to 13 mm and a length of 5 mm to 15 mm.

These nuclear fuel pellets must be free from defects such as cracks and chips on their outer surfaces (including both end and side surfaces). For this reason, the quality of nuclear fuel pellets is guaranteed by visually inspecting all nuclear fuel pellets before use.

Conventionally, this visual inspection method is
The nuclear fuel pellets are placed on a tray and carried to the inspection table.
A method in which the nuclear fuel pellets are picked up one by one with tweezers or the like and a complete visual inspection is performed; the nuclear fuel pellets are placed directly or via a tray on a conveyor in an upright or lying position, and while being moved; Nuclear fuel pellets are visually inspected by picking them up one by one with tweezers, etc. A number of grooves with an arcuate cross section are provided on the bottom of the tray, nuclear fuel pellets are arranged in a lying position in these grooves, and the tray is vibrated with a vibrator. A method is used in which the outer circumferential surface of the vibrating nuclear fuel pellets is visually inspected, and if necessary, the nuclear fuel pellets are picked up one by one with tweezers and the end surfaces are inspected.

However, in the conventional visual inspection method described above, from the standpoint of protecting the hands from local exposure to radiation, one is forced to wear radiation shielding gloves that significantly impair work efficiency. It is inefficient, difficult to inspect, and places a heavy burden on workers. In addition, although the above method improves the inspection speed slightly, it is not sufficient.
It is still difficult to inspect, and the burden on workers remains high. Furthermore, although the inspection speed is further improved in the above method, the equipment is insufficient, such as the fact that the nuclear fuel pellets on the tray cannot be rotated evenly with only vibration by the vibrator, resulting in significant eye and hand fatigue for the operator. Therefore, there were problems such as unavoidable inspection errors such as uneven inspection.

Therefore, in order to solve the above problems, the present applicant has proposed a new nuclear fuel pellet visual inspection device (Japanese Patent Laid-Open No. 57-93238). This visual inspection device is
As shown in FIGS. 11 and 12, the base 1
is positioned and fixed at a predetermined location on this base 1, and a plurality of nuclear fuel pellets P are placed on top of it.
a tray 2 on which nuclear fuel is placed; a rotating roller group 4 provided adjacent to the tray 2 which is positioned and fixed on the base 1 and rotated in the same direction by a drive mechanism 3; It is comprised of a transfer mechanism 5 for transferring pellets P from either the tray 2 or the rotating roller group 4 to the other.

In the above visual inspection apparatus, nuclear fuel pellets P regularly arranged on a tray 2 are transferred onto a group of rotating rollers 4 by a transfer mechanism 5, and a large number of pellets P are transferred between both rollers 4a. are simultaneously rotated in a predetermined direction at a constant speed, thereby achieving highly efficient inspection. According to the above-mentioned inspection device, the inspection speed is increased, the work burden on the operator is reduced, and the nuclear fuel pellet P has no rotational unevenness, thereby eliminating inspection errors such as unevenness of inspection. I am getting the same effect as I could.

``Problems to be Solved by the Invention'' However, although the pellet appearance inspection apparatus described above can reliably inspect the side surfaces of the pellets P, the pellets There was a problem in that the end face of the pellet could not be inspected when it was transferred upward.

The present invention was made in view of the above circumstances, and
The purpose is to provide a nuclear fuel pellet visual inspection device that can reliably inspect not only the side surfaces but also the end surfaces of nuclear fuel pellets, and that can efficiently carry out highly reliable visual inspections. .

"Means for Solving the Problems" In order to achieve the above object, the present invention includes a base, a cylindrical nuclear fuel pellet positioned and fixed at a predetermined location on the base, and a cylindrical nuclear fuel pellet lying on the top of the base. A plurality of trays arranged in series in the axial direction, a group of rotating rollers for rolling pellets provided on both sides of the position on the base where the trays are positioned and fixed, and a group of rotating rollers that are positioned and fixed on the base. a first transfer mechanism that adsorbs only every other pellet in the length direction of the plurality of pellets placed on the tray and transfers the pellets to either one of the left and right rotating roller groups; , the plurality of pellets left on the tray are transferred in parallel and placed on the other group of rotating rollers, and the pellets on the group of rotating rollers are transferred in parallel and placed on the tray again. The configuration includes a second transfer mechanism.

"Operation" Of the nuclear fuel pellets regularly arranged on the tray, only those located every other in the length direction are adsorbed by the first transfer mechanism and transferred to either the left or right rotating roller adjacent to the tray. transferred to one side of the group. The nuclear fuel pellets remaining on the tray are subjected to an end face inspection on this tray, and then transferred to the other group of rotating rollers by a second transfer mechanism, and then forcibly rolled by the rotating rollers. A side inspection is performed. Next, the pellets transferred to the one group of rotating rollers are forcibly rolled by each rotating roller, and the end and side surfaces are simultaneously inspected.

In this manner, both the end and side surfaces of each pellet are inspected. After the inspection is completed,
The pellets placed on the left and right rotating roller groups are again transferred onto the tray by the second transfer mechanism and returned to their original arrangement.

"Embodiment" Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the configuration of the main parts of the device according to the present invention. As shown in the figure, the general configuration of this device includes a base 11 and a fixed position positioned at a predetermined location on the base 11. and a tray 12 on which cylindrical nuclear fuel pellets P are regularly arranged vertically and horizontally (in the figure, the direction A is defined as vertical and the direction B is defined as horizontal), and the base 11. Tray 1
A group of rotating rollers 13 and 14 for rolling the pellet P are provided adjacent to both sides of the position where the pellet P is positioned and fixed, and a tray 12 is placed on the tray 12 which is positioned and fixed on the base 11. Among the plurality of pellets P, only the pellets P located every other column (row) in the vertical direction are adsorbed and transferred onto the left rotating roller group 13 (either the left or right rotating roller groups 13, 14). However, in this case, it is above the left rotating roller group 13)
A transport mechanism 15 is used to transport the plurality of pellets P left on the tray 12 in parallel and place them on the other rotating roller group 14, and to transfer the pellets P on the rotating roller groups 13 and 14. A second transfer mechanism 16 is provided which transfers the paper in parallel and places it on the tray 12 again after the inspection is completed.

Next, to describe these details, a tray transfer processing mechanism (not shown) is attached to the base 11, which moves the tray 12 from the tray transport path connected to the pellet processing device in the previous stage to a predetermined location on the base 11. operation, transfer tray 1 at that position.
2 by a clamp mechanism, and
After the visual inspection of the pellets P is completed, the entire operation of returning the tray 12 to the original tray transport path is automatically performed.

Further, the base 11 is provided with a vibrator (not shown), which vibrates the tray 12 set on the base 11 so that the pellets P arranged on the top thereof can be spaced a little apart from each other. It's getting old.

The rotating roller groups 13 and 14 are bilaterally symmetrical, and only the rotating roller group 13 will be explained here, and the same reference numerals will be used for the rotating roller group 14 on the other side, and the explanation thereof will be omitted.

The individual rotating rollers 13a, . It is designed so that

As shown in FIG. 2, one end of the rotating rollers 13a, . , 21a, and is rotatably supported by a bearing 22 sandwiched between the bearings 21a and 21a. Further, a roller gear 23 is connected to a nut 2 at one end of each rotating roller 13a, .
3a, and these roller gears 23 are each connected via an idle gear 24 to
It is connected to a pair of drive gears 25. and,
These drive gears 25 are connected to a pair of motors 27 via a torque tender 26, and by operating these motors 27, the drive gears 25, 25, an idle gear 24, and a roller gear 23 are connected to each other. , each rotating roller 13a,...
are arranged to rotate simultaneously in the same direction and at the same speed. The roller rotation drive mechanism 19 is comprised of these gears 23, 24, 25, a torque tender 26, and a motor 27.

On the other hand, the other end of the rotating rollers 13a,...
As shown in the figure, the roller support 18 is rotatably supported by a bearing 29 that is removably fitted into an arcuate groove 28 formed on the upper surface of the roller support 18 .

The first transfer mechanism 15 will be explained as follows.
As shown in FIG. 1, the base 11 has two supports 3.
0 are erected on the left side of the left rotating roller group 13 and on the right side of the tray 12 set in the center of both the rotating roller groups 13 and 14, with a predetermined interval between them. . Guide rods 31, 31 extending in the left-right direction are provided vertically and in parallel at predetermined intervals on these columns 30, 30.
1 and 31, a vertical movable table 32 assembled in a rectangular shape is moved in the left-right direction by a slider 32a integrally fixed to this movable table 32 being inserted through a guide rod 31 and guided. They are arranged freely. Further, a threaded rod 33 is rotatably provided between the guide rods 31, 31 and parallel to the guide rods 31, 31 on the pillars 30, 30, and this threaded rod 33 is rotated by a motor 34 fixed to the pillar 30. While being operated, it is screwed into a female screw member 35 that is integrally fixed to the vertically movable table 32.

Further, guide rods 36 extending in the vertical direction are fixed to the vertical moving table 32 in parallel at predetermined intervals.
A horizontal movable table 37 assembled in a T-shape when viewed from above is attached to the guide bars 36, 36.
A slider 37a, which is integrally fixed to the slider 7, is inserted through and guided by the guide rod 36, thereby being supported so as to be movable in the vertical direction. Further, a screw rod 38 is rotatably attached to the vertically movable table 32 parallel to the guide rods 36, and the screw rod 38 is rotatably operated by a motor 39 fixed to the vertically movable table 32. At the same time, it is screwed into a female screw member 40 that is integrally attached to the horizontal moving table 37.

That is, by operating the motor 34, the horizontal moving table 37 is moved in the left and right direction integrally with the vertical moving table 32, and by operating the motor 39, the horizontal moving table 37 is moved. is operated independently to move up and down.

Attached to the horizontal movement table 37 is an adsorber 41 for adsorbing only every other pellet (row) in the length direction of the nuclear fuel pellets P placed on the tray 12. ing. As shown in FIG. 3 and FIG.
and a box body 43 forming a sealed space between the box body 4 and the box body 43.
It is connected to a vacuum pump (not shown) via a flexible tube 44 connected to the upper center of the tube 3 (see FIG. 1). A plurality of arc-shaped grooves 45 corresponding to the pellets P arranged on the tray 12 are formed in parallel on the lower surface of the bottom plate 42,
Holes 46 communicating with the internal space of the suction device 41 are provided at appropriate intervals in the inner parts of these grooves 45 . The distance between the holes 46 is determined by the length of the pellet P.
When it is set to almost 2L.

The second transfer mechanism 16 will be explained as follows.
As shown in FIG. 1, a pair of guide rods 50, 50 are arranged parallel to each other on the sides of the rotating roller groups 13, 14 and the tray 12 set between them. A pair of left and right pellet feeding supports 52A and 52B are provided along the linear motion bearing 51 so as to be movable in the left and right direction (direction A in the figure). These pellet feeding supports 52A, 52B are connected to each other by a connecting member 53, and each pair of connecting plates 54 is attached to each pellet feeding support 52A, 52B in a hanging manner. A claw holding arm 55 is rotatably attached to the lower part of the connecting plate 54, as shown in FIG. The claw holding arm 55 is
A plurality of (for example, 25) claw retaining rings 58 are attached around each of the claw support shafts 57, and claws 59 are attached to each claw retaining ring 58 in a row by welding. Also,
As shown in FIG. 6a, the insertion holes 60 formed in each claw retaining ring 58 are normally fitted with slip pins 62 that are fitted into grooves 61 formed in the axial direction of the claw support shaft 57. , this slip pin 62 is attached to the pawl retaining ring 58 (claw support shaft 57).
A spring 63 is inserted and pressed from above by a spring force adjustment screw 64. As described above, the claw support shaft 57 of the claw holding arm 55 is rotatably supported by the connecting plate 54 and is rotated by the rotating mechanism 65 attached to one of the connecting plates 54. It has become.

This second transfer mechanism 16 allows the pellets P arranged on the tray 12 to be transferred onto either the left or right rotating roller groups 13, 14, or vice versa. When transferring onto the tray 12, first, as shown in FIG. 6b, the claw support shaft 57, on which the claw 59 is normally inclined, is rotated counterclockwise by the rotation mechanism 65. Claw 59 as shown in a
so that it faces straight down. At this time, the tip of the claw 59 is in a state where it can engage with the pellet P.

The tip of the claw 59 is brought into a state where it can engage with the pellet P, and then the pair of left and right pellet feeding supports 52A, 52B is moved in any direction in the A direction in FIG. 1 by a drive mechanism (not shown). The pellet P is moved as desired.

When transferring the pellets P, for example, if the leading pellet P in the transfer direction gets caught on the tray 12 or the rotating rollers 13a, 14a, the slip pin 62 rides on the edge of the groove 61 and the biasing force of the spring 63 is released. The claw support ring 58 and the claw support shaft 57 are disengaged from each other, and the claw support ring 58 is freed.
9 and pellets P are prevented from being damaged.

Further, the rotary roller groups 13 and 14 have their end portions facing the tray 12 connected to the tray 12.
A rotating roller transfer mechanism 71 for bringing the tray into contact with the tray 12 or separating it from the tray 12.
is provided.

This rotary roller transfer mechanism 71 is installed below the end of the rotary roller groups 13 and 14 on the side facing the tray 12, and as shown in FIGS. 7 to 9, each rotary roller 13a , 14a, a roller push-up fitting 72 for pushing up the ends of
, a roller push-up stand 73 that supports the push-up fitting 72 movably in the vertical direction, a spring 74 provided between the roller push-up fitting 72 and the roller push-up stand 73, and the roller push-up stand 73.
and a cylinder device 76 to which a piston rod 75 is connected. Further, on the upper surface of the rotating roller push-up fitting 72, a rotating roller 13 is provided.
An arcuate groove 77 for supporting one end of the rotating rollers 13a, 14a is formed to correspond to the installation location of each roller 3, 4, and the radius of curvature of the groove 77 is set to support one end of the rotating rollers 13a, 14a. (supporting part). Furthermore, a tapered surface 78 is formed on the rotating rollers 13a, 14a near the contact portion between one end of the rotating rollers 13a, 14a and the tray 12.

The rotating roller transfer mechanism 71 transfers pellets P between the rotating roller groups 13 and 14 and the tray 12.
Used when transferring. That is, when transferring the pellet P to the other side, the piston rod 75 of the cylinder device 76 is raised.
Then, the corrugated plate 12A of the tray 12 comes into contact with one end of the rotating rollers 13a, 14a, and the roller push-up fitting 7 of the roller transfer mechanism 71
By setting the radius of curvature of the groove 77 formed in the groove 2 to be larger than the radius of curvature of one end (supporting part) of the rotating rollers 13a, 14a, it is possible to temporarily connect one end of the rotating rollers 13a, 14a with the tray. Even if some horizontal deviation occurs between the corrugated plates 12A and 12, it is smoothly absorbed, and one end of the rotating rollers 13a, 14a and the corrugated plates 12A are firmly attached. Therefore, the level difference between the tray 12 and one end of the rotating rollers 13a, 14a can be minimized, and the pellets P can be transferred smoothly.

Next, the operation of the visual inspection apparatus configured as described above will be explained.

(1) First, the tray 12 sent from a transport path (not shown) is transported to a predetermined location on the base 11 via a tray transfer mechanism (not shown), and set at that position via a clamp mechanism. Then, the set tray 12 is vibrated with a vibrator (not shown) to cause the pellets P arranged on the tray to be spaced apart from each other by a very small amount.

(2) Next, among the plurality of pellets P arranged on the tray 12, every other pellet (row) in the lengthwise direction of the pellets P is adsorbed by an adsorber 41 using a vacuum, and then the motor 34 , 39, the suction device 41 is moved onto the rotating roller group 13 on the left side in FIG. 1, the vacuum is released there, and the pellet P is placed on the rotating roller group.

(3) For every other pellet (row) P remaining on the tray 12, both left and right end faces are inspected.

(4) After the end face inspection, the pellets P remaining on the tray 12 are transferred by the second transfer mechanism 16 onto the rotating roller group 14 on the right side in FIG. The pellet P is forcibly rotated at the same speed and in the same direction, and the side surface of the pellet P is inspected.

(5) The pellet P transferred onto the left rotating roller group 13 is forcibly rotated at the same speed and in the same direction via each rotating roller 13a, so that both the side and end faces of the pellet P are rotated. Tests are performed at the same time.

Both the end and side surfaces of all pellets P are inspected as described above, but if there are any defective pellets P (chips, cracks, etc.) during the inspection,
Each time, the defective pellet is taken out using a gripping means such as tweezers.

(6) When the above-mentioned inspection is completed, first, the pellets P on the left rotating roller group 13 are returned onto the tray 12 by the second transfer mechanism 16.

(7) Next, the pellets P on the right rotating roller group 14 are transferred to the tray 12 by the second transfer mechanism 16.
Return to top.

(8) Next, the normal pellets P collected on the tray 12 after the inspection are automatically returned to the original conveyance path along with the tray 12 by a tray conveyance mechanism (not shown), and the tray 12 is taken out.

In the above embodiment, a vacuum suction means is used as a means for transferring every other pellet in the length direction of the pellets P on the tray 12 onto the rotating roller group 13.
This is because this means has the advantage that the pellets P are less likely to be damaged.

"Effects of the Invention" As explained above, according to the present invention, the base and
a tray that is positioned and fixed at a predetermined location on the base, and on the top of which a plurality of cylindrical nuclear fuel pellets are arranged in a lying state and connected in the axial direction;
A group of rotating rollers for rolling the pellets, which are provided on both sides of the position where the tray of the base is positioned and fixed; A first transfer mechanism that sucks only every other pellet in the length direction and transfers it to either one of the left and right rotating roller groups; and a first transfer mechanism that transfers the plurality of pellets left on the tray in parallel. The structure includes a second transfer mechanism that transfers the pellets on the other group of rotating rollers in parallel and places them on the tray again. Not only the side surfaces but also the end surfaces of the pellets can be reliably inspected, and highly reliable external appearance inspections can be carried out efficiently.

[Brief explanation of drawings]

1 to 10 show an embodiment of the present invention, FIG. 1 is a perspective view showing the configuration of the main parts, FIG. 2 is a perspective view showing the drive mechanism of the rotating roller, and FIG. 3 is a suction device. FIG. 4 is an explanatory view of the operation of the adsorber, FIG. 5 is a perspective view of the second transfer mechanism, and FIG.
Figures a and b are explanatory diagrams of its operation, Figure 7 is a sectional view showing the support part of one end of the rotating roller, Figure 8 is a sectional view taken along the - line in Figure 7, and Figure 9 is the same as that in Figure 7. −
10 is an explanatory diagram of the operation of a rotating roller, FIGS. 11 and 12 show a conventional example of a pellet appearance inspection device, and FIG. 11 is a side view.
FIG. 12 is a plan view. 11... Base, 12... Tray, 13, 14...
...Rotating roller group, 13a, 14a...Rotating roller, 15...First transfer mechanism, 16...Second transfer mechanism, 32...Vertical moving table, 34...Motor,
37...Horizontal moving table, 39...Motor, 41...
Adsorption device, 42...bottom plate, 43...box body, 44...
...Flexible tube, 46...holes.

Claims (1)

[Claims] 1. A base, a tray positioned and fixed at a predetermined location on the base, and on the top of which a plurality of cylindrical nuclear fuel pellets are lined up in a lying state in the axial direction, and the tray of the base is A group of rotating rollers that roll the pellets are provided on both sides of the position where the pellets are positioned and fixed, and one of the plurality of pellets placed on the tray that is positioned and fixed on the base. a first transfer mechanism that sucks only individual pellets and transfers them to one of the left and right rotating roller groups; and a first transfer mechanism that transfers a plurality of pellets left on the tray in parallel to rotate the other roller group. Appearance inspection of nuclear fuel pellets, comprising: a second transfer mechanism for placing the pellets on a group of rollers, transferring the pellets on the group of rotating rollers in parallel, and placing the pellets on the tray again. Device.