JPS6342240B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a welding device for welding a cladding tube and an end plug of a nuclear fuel rod for a nuclear reactor.

[Technical background of the invention and its problems]

Generally, in a nuclear fuel rod for a nuclear reactor, a unique symbol of the nuclear fuel rod is engraved on the outer peripheral surface of the end plug. By the way, the above-mentioned unique symbol is stamped on the end plug of the nuclear fuel rod before it is welded to the cladding tube.

Therefore, in manufacturing nuclear fuel rods, in addition to the end plug welding process, an end plug stamping process is also required, and after stamping, it is also necessary to manage the identification of each end plug. Furthermore, conventionally, stamping has been performed using a punch method, so there are problems such as impact being applied to the end plug during stamping, which may cause distortion and deformation, and that it is difficult to adjust the depth of the stamp, etc.

[Purpose of the invention]

In view of these points, the present invention is a nuclear fuel that reduces the number of steps by performing end plug welding and end plug stamping in a welding chamber in one process, and also avoids impacting the end plug during marking. The purpose is to obtain stick welding equipment.

[Summary of the invention]

The present invention corresponds to the position of the end plug attached to the open end of the cladding tube, in the wall part perpendicular to the side wall in which the cladding tube insertion opening is drilled in the welding chamber where the cladding tube and the end plug are welded. At the same time, a laser beam introduction window is provided on the outside of the welding chamber, and a laser beam generated by the laser beam generation device is irradiated onto the outer surface of the end plug through the laser beam introduction window. However, the end plug is characterized by being provided with an end plug stamping head for stamping an identification symbol on the outer circumferential surface of the end plug.

[Embodiments of the invention]

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

In FIG. 1, reference numeral 1 denotes a sealed welding chamber, and one side wall of the welding chamber 1 is provided with an opening 3 into which the end of the cladding tube 2 can be inserted. The outer surface of the end plug 4 attached to the end of the cladding tube inserted into the welding chamber 1 and a position corresponding to the joint a of the end plug 4 of the cladding tube 2 are provided on the wall perpendicular to the welding chamber 1. To,
A window 5 for introducing laser light is provided.

On the other hand, a laser beam generator 6 is provided on the outside of the welding chamber 1, and the laser beam generated by the laser beam generator 6 is transmitted to the end plug welding head via a laser beam branching device 7. 8 and end plug marking head 9. By the way, the laser beam transmitted to the end plug welding head 8 passes through the laser beam introduction window 5 and is focused on the joint a of the cladding tube 2 and the end plug 4, welds that part, and also welds the end plug. The laser beam transmitted to the marking head 9 passes through the laser beam introduction window 5 and is irradiated onto the outer circumferential surface of the end plug 4 attached to the end of the cladding tube 2, and an identification mark is marked on the outer circumferential surface of the end plug 4. is engraved on it. That is, the above identification symbol consists of a number composed of alphabetic letters and numbers, for example,
Marking is carried out by controlling the laser beam emitted from the end plug marking head 9 by a signal sent to the end plug marking head 9 from the outside.

Therefore, when welding the end plug 4 to the cladding tube 2, the open end side of the cladding tube 2 is inserted into the welding chamber 1 through the opening 3, and the end plug 4 is welded to the cladding tube 2 by an end plug press-fitting mechanism (not shown). The laser beam from the end plug welding head 8 is focused on the joint between the end plug 4 and the cladding tube 2 through the laser beam introduction window, and the cladding tube 2 is rotated. The joints are welded.

On the other hand, the laser beam emitted from the end plug marking head 9 is transmitted to the outer surface of the end plug 4 through the laser beam introduction window 5, and a predetermined identification symbol is engraved by the transmitted laser light.

In this way, the identification symbol can be engraved at the same time as the end plug 4 is welded. In this case, the end plug welding and the end plug stamping may not be performed simultaneously but sequentially.

FIG. 2 is a diagram showing the appearance of the nuclear fuel rod obtained in the above example after welding and stamping an identification symbol, and a symbol 10 consisting of alphanumeric characters and numbers consecutive in the circumferential direction is stamped on the outer periphery of the end plug 4. has been done.

In the above embodiment, the welding of the cladding tube and the end plug is performed using a laser beam, but the end plug welding described above may also be performed by other methods such as gas tungsten arc welding. good.

〔Effect of the invention〕

As explained above, according to the present invention, the identification symbol is engraved by irradiating the end plug in the welding chamber with a laser beam, so that the identification symbol is engraved on the end plug. This process can be performed in the same process as the plug welding process, and the number of nuclear fuel rod manufacturing processes can be reduced by one compared to the conventional method. Furthermore, since no identification symbol is engraved on the end plug before the end plug welding process, it becomes unnecessary to manage the identification of each end plug in the process before the end plug welding process, and it is possible to reduce the cost of manufacturing nuclear fuel rods. Furthermore, since the identification symbol is engraved with a laser beam, there is no impact on the end plug during marking, and the depth of the marking can be freely adjusted by adjusting the laser beam. Moreover, when the laser light source for end plug welding and the laser light source for end plug marking are shared as in the embodiment described above, the effect of reducing equipment costs can also be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a nuclear fuel rod welding apparatus of the present invention, and FIG. 2 is an external view of the fuel rod after welding and marking of an identification symbol. 1... Welding chamber, 2... Cladding tube, 3...
Opening, 4...End plug, 5...Laser light introduction window, 6
...Laser beam generator, 7...Laser beam branching device, 8...End plug welding head, 9...End plug stamping head.

Claims (1)

[Scope of Claims] 1. An end plug attached to the open end of the cladding tube on a wall perpendicular to the side wall in which the cladding tube insertion opening is bored in the welding chamber in which the cladding tube and the end plug are welded. A laser beam introduction window is provided corresponding to the position, and a laser beam generator is provided on the outside of the welding chamber, and the laser beam generated by the laser beam generator is passed through the laser beam introduction window to the outside of the end plug. A nuclear fuel rod welding device characterized by being provided with an end plug marking head that irradiates the surface and stamps an identification symbol on the outer peripheral surface of the end plug. 2. The nuclear fuel rod welding apparatus according to claim 1, wherein the laser beam generator is configured to transmit laser light to the end plug welding head together with the end plug marking head.