JPS63278765A - Identification marking device for nuclear fuel rod - Google Patents

Abstract

PURPOSE:To enable the efficient marking of an identification sign by blasting abrasives such as beads to the sheathed pipes of nuclear fuel rods via the masking members of projected form corresponding to the identification sign to be marked. CONSTITUTION:Feed rollers 3 for a sheathed pipe drawing mechanism are made in contact with the upper and lower sides of corresponding sheathed pipes 2, and inserted and positioned in the groove 5 of a pedestal 6. And a control signal from the computer wherein an identification sign to be marked is preliminarily stored, is applied for causing the rotation of plate sheathed rollers 8A-8D independently with each roller turning mechanism 9. And the through-hole patterns 11 of each plate 10A-10D are so aligned as to make a 4-digit number and a blasting mechanism and an abrasive recovery mechanism are actuated. Furthermore, abrasives such as beads are blasted from a projection nozzle 13 and an identification sign is thereby marked on the sheathed pipes 2. The same processes as aforementioned are repeated for marking the sign on each sheathed pipe 2 on a belt conveyor 1. According to the aforementioned system, the identification sign can be efficiently marked and the sheathed pipe 2 can be inserted in a reactor core without removing a label as different from the conventional system.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an identification code writing device for writing identification codes such as serial numbers on nuclear fuel rods.

``Prior Art'' Nuclear fuel rods are marked with identification codes such as production numbers or loft numbers so that the manufacturing process can be traced in the event that a problem occurs.

Common methods for writing this type of identification code include laser marking, corrosion, marking with a punch, and marking with a vibrating pen, but all of these methods damage the surface of the cladding. Due to the thin wall thickness of the cladding tube, it cannot be used for nuclear fuel rods for safety reasons. Furthermore, since impurities are strictly controlled within the reactor core, marking methods using paint or the like cannot be implemented.

Due to the above constraints, the current method is to attach labels with printed numbers to the cladding tubes when manufacturing nuclear fuel rods, and then remove these labels when assembling nuclear fuel assemblies. There is.

``Problems to be solved by the invention'' However, in the method using the above-mentioned labels, labels must be attached and peeled off manually to each of the several hundred or more nuclear fuel rods in a nuclear fuel assembly. The drawbacks are that it takes a lot of time and effort to do this, and costs such as disposable labels and labor costs are also high.

"Means for Solving the Problems" The present invention is intended to solve the above problems, and includes a blasting mechanism that projects an abrasive material such as beads onto a nuclear fuel rod, and a part of the nuclear fuel rod that is to be projected. The present invention is characterized by comprising a mask mechanism covered with a mask member having a projected shape corresponding to an identification code.

"Operation" This device projects abrasive onto the surface of the cladding tube using the blast mechanism, and partially blocks the projection of the abrasive using the mask member of the mask mechanism.
A finely uneven surface having a shape corresponding to the identification code to be written is formed. Since such an uneven surface diffusely reflects incident light, the identification code stands out on the surface of the cladding tube, which has metallic luster.

"Embodiments" Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of an identification code writing device according to an embodiment.

Reference numeral I in the figure is a belt conveyor that moves intermittently by a fixed distance, and a large number of nuclear fuel rod cladding tubes 2 are placed in parallel on this belt conveyor l at intervals equal to the moving distance. It has become.

A cladding tube extraction mechanism (path shown) is provided on the side of the belt conveyor 1 and includes a pair of upper and lower feed rollers 3, 3, and is controlled by a computer (not shown). As a result, when the cladding tube 2 is transferred to the position corresponding to the roller 3°3, it is moved from above and below by the rollers 3,
3, and the cladding tube 2 is pulled out laterally by rotating the rollers 3.3.

A belt conveyor l is installed on the side from which the cladding tube 2 is extracted.
A pedestal 4 is arranged parallel to the. A pedestal 6 having a groove 5 with a V-shaped cross section is arranged in the center of the pedestal 4, and the cladding tube 2 is positioned so as to slide along the groove 5 of the pedestal 6. ing.

Further, a mask mechanism 7 is installed on the pedestal 4. The mask mechanism 7 includes four plate winding rollers 8A to 8D arranged on each side of the pedestal 6, and a stepping motor that coaxially supports these rollers 8A to 8D and rotates them individually. A roller rotation mechanism 9 equipped with
．． These roller rotation mechanisms 9.9 are connected to the computer.

Rollers 8A, 8A (~8
Both ends of a long and thin strip-shaped license plate (mask member) IOA (~10D) are wound around D, 8D), and the central part of each license plate IOA~10D is wrapped around the cladding tube 2 on the pedestal 6. are positioned so that they abut on the outer circumferential surfaces of the two without any gaps. These license plates IOA to IOD are made of a thin material strong enough to withstand the projection of abrasives, and have through holes 1 to 9 in the shape of numbers "θ to 9". Many are formed in a row. Also, for the two license plates IOA and IOD on both sides, the abrasive is applied to the cladding tube 2.
It is wider than the others to avoid hitting unnecessary parts of the body.

Above the contact area between the license plate IOA~lOD and the cladding tube 2, there is a plate surrounding this! A box-shaped cover 12 is provided to moderately hold down 0A-10D, and a bead projection nozzle 13 is fixed through the upper wall surface of this cover 12. The projection nozzle 13 is connected to a blasting mechanism (not shown), and is configured to project abrasives such as glass beads and SiC beads toward the contact portion. Further, a dust collection mechanism (path shown) is arranged around the pedestal 6 to collect the abrasive scattered inside the cover 12 and around the pedestal 6 by suction and return it to the blasting mechanism.

Next, the operation of this device will be explained.

First, the feed rollers 3゜3 of the cladding tube extraction mechanism are brought into contact with the cladding tube 2 at the corresponding positions from above and below, and these rollers 3,
3 and insert the cladding tube 2 into the groove 5 of the pedestal 6 to position it.

Next, the roller rotation mechanism 9.9 is activated in response to a control signal from a computer in which the identification code to be entered is stored in advance.
The plate winding rollers 8A to 8D are individually rotated, and the through holes 11 of each plate IOA to 10D are arranged so that a predetermined four-digit number is formed at the contact portion.

Next, activate the blast mechanism and abrasive recovery mechanism,
The abrasive is projected from the projection nozzle 13 onto the contact portion for a certain period of time. Then, the abrasive collides with the surface of the cladding tube 2 through the through holes 11, and a very slight uneven surface in the shape of the numbers is formed.

Next, the feed rollers 3, 3 of the cladding tube extraction mechanism are rotated again to return the cladding tube 2 onto the belt conveyor 1, the belt conveyor 1 is advanced by one section, and the above operation is repeated from the beginning.

According to the nuclear fuel rod identification code writing device of the present invention having such a configuration, it is possible to automatically write identification codes on a large number of cladding tubes 2. Compared to the traditional method of applying labels manually, it is much more efficient and has improved reliability. In addition, since impurities such as paint do not adhere to the cladding tube 2 after entering the number,
... can be loaded into the reactor core as is, there is no need to remove it like a label, and there is also the advantage that the processing cost per cladding tube is low.

Furthermore, since the identification number written by this device is made up of extremely fine uneven surfaces, there is no risk of affecting the wall thickness of the cladding tube 2 or causing a decrease in strength. Furthermore, despite these extremely minute irregularities, the identification number stands out clearly in contrast with the other parts of the cladding, which have a nearly mirror-like luster, making them easy to identify. No less than a label.

3 and 4 are graphs of the depth from the surface and the surface roughness at the coded portion when the code is written on the cladding tube 2 using the same device as described above. Both graphs show the results of measurement by sliding the stylus T of the surface roughness meter along the numbered portions as shown in FIG.

(A), (B), (C), (D), (B) in Figure 3
) are bead blasts for 1 second, 2 seconds, 3 seconds, and 4 seconds, respectively.
The graph shows the cases where the test was carried out for 4 seconds and 4 seconds, and it was not possible to detect the amount of dent in the numbered part with the resolution of these graphs.

Also, Fig. 4 (A), (B), (C), (D'')
Similarly, 1 second.

The surface roughness is shown when bead blasting is performed for 2 seconds, 3 seconds, and 4 seconds, and even when the blasting time is the longest, 4 seconds, the surface roughness remains at only 1.5μ. I used it. Incidentally, even when the blasting process was for 1 second, the codes written on the cladding tubes were sharp enough to be clearly identified.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and various modifications such as those described below are possible.

For example, in the apparatus of the above embodiment, the code was written only on a part of the outer circumferential surface of the cladding tube 2, but a rotation mechanism for rotating the cladding tube 2 after blast projection by a predetermined angle around the axis is provided on the - side. By attaching the beads and projecting the beads again onto the rotated cladding tube, codes can be written in two or more places on the outer circumferential surface.

Also, instead of blasting one tube at a time as in the above device, a license plate is arranged to cover the ends of multiple cladding tubes lined up in parallel, and the nozzle of the blast mechanism is placed along the plate. It is also possible to have a configuration in which the abrasive is scanned and the abrasive is projected onto the plurality of cladding tubes one after another,
In that case, it becomes possible to further improve processing efficiency.

Further, the shape of the mask member is not limited to the belt shape as described above, but may be a rotating plate shape or the like.

Further, although the above embodiment shows a configuration in which a four-digit number is entered, it goes without saying that the number is not limited to four digits.

"Effects of the Invention" As explained above, according to the nuclear fuel rod identification code writing device of the present invention, identification codes can be automatically written on a large number of cladding tubes. Compared to the traditional method of manually applying labels to objects, it is much more efficient and highly reliable.

Furthermore, since the cladding tube with the identification code written on it can be directly inserted into the reactor core, there is no need to remove it like a label, and the processing cost can be reduced.

Furthermore, since the identification code written by this device is composed of extremely fine irregularities, there is no risk of affecting the wall thickness of the cladding tube or causing a decrease in the strength of the cladding tube.

Moreover, even though this identification code has extremely minute irregularities as mentioned above, it stands out clearly in contrast with the other parts of the cladding tube, which has a near-mirror gloss, so it is easy to identify. No less than a label.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a nuclear fuel rod identification code writing device according to an embodiment of the present invention, FIG. 2 is a front view showing a measuring method for explaining the present invention in detail, and FIGS. (E) and FIGS. 4(A) to (D) are graphs showing the effects of the present invention. l... Belt conveyor, 2... Nuclear fuel rod cladding tube,
3... Roller of cladding tube extraction mechanism, 4... Frame, 6... Rest, 7... Mask mechanism, 8A to 8D... Plate winding roller, 9...
Roller rotation mechanism, 10A to IOD... License plate (mask member) 11... Through hole corresponding to identification code, 12... Cover, Summer 3... Bead projection nozzle.

Claims (1)

[Claims] A nuclear fuel rod comprising: a blasting mechanism for projecting an abrasive material onto a nuclear fuel rod; and a masking mechanism for covering a projected portion of the nuclear fuel rod with a mask member having a projected shape corresponding to an identification code to be written. identification code entry device.