JPS60181699A - Method of controlling cutting of high radioactive solid waste volume reducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for controlling cutting of a highly radioactive solid waste volume reduction apparatus using a water jet cutting method using an electrode.

[Background of the invention]

The conventional water jet cutting method uses a constant voltage control method that keeps the wire feeding speed and cutting speed constant.
JP-A-50-78549 “Consumable electrode type arc cutting method”
Also known by. The cutting principle will be explained with reference to FIG. In the figure, 1 is a feeding roller, 2 is an electrode wire, 3 is a power source, 4 is a contact tip, 5 is a material to be cut,
6 is a nozzle, 7 is a water supply port, 8 is a feed motor, and 9 is a wire reel. The electrode wire 2 melts the cut portion of the workpiece 5 by arc discharge, and the molten metal is blown off by the high-pressure water jetted from the nozzle 6, thus causing the workpiece 5 to melt.
will be severed. However, in the constant voltage cutting control method in which the feeding speed and cutting speed of the electrode wire 2 are constant, for example, there may be cases where variations in the thickness of the material to be cut 5 cannot be adequately followed and cutting becomes impossible. Also, nozzle 6
Stable cutting performance may not necessarily be obtained in response to variations in various cutting conditions due to the shape specifications of the material to be cut, such as variations in the distance (standoff) between the material to be cut and the material to be cut. That thing is a cone.

In this case, the conventional cutting control system has the disadvantage that uncut portions are left on the material to be cut during the cutting operation.

[Purpose of the invention]

The present invention has been made in view of the above circumstances.
FJ? The purpose of this invention is to provide a cutting control method for a highly radioactive solid waste volume reduction device that can cut smoothly even if the material has deformed shape or the like and reduces the number of work steps.

[Summary of the invention]

The cutting control method of a highly radioactive solid waste volume reduction device according to the present invention includes a highly radioactive solid waste material to be cut that is moved in a predetermined direction, and a material that is arranged laterally with respect to the moving direction of the material to be cut. A welding type quarter that generates an arc discharge between the electrode wire and the electrode wire that is sent out sequentially through a feeding roller, and blows and cuts the melted part of the material to be cut by the arc discharge using high-pressure water jetted from a nozzle. In the case of jet arc cutting, the current during the arc discharge is detected, and when the current reaches zero or a predetermined current value or less for a predetermined time, the cutting operation is temporarily stopped and the material to be cut is This is a method in which the electrode wire position is moved backward relative to the direction of movement at the time of cutting, and discharge is started again, and these operations are controlled so that they are performed automatically.

The molten water jet cutting method converts electrical energy into thermal energy to melt and cut the material to be cut. In stable cutting conditions, constant voltage cutting control is possible and the cutting current is relatively stable. It was experimentally confirmed that the cutting current fluctuates greatly under unstable cutting conditions. Figure 4 shows the results of this experiment.

The person in Figure 4 shows a time of 10 m5ec. In the figure, in a state of stable cutting, the current value appears to fluctuate greatly due to the characteristics of the arc discharge phenomenon, but this is a phenomenon of about several rleo in time.

On the other hand, in the case of an unstable cutting state, a phenomenon was confirmed in which the current value lasted for more than several tens of m6'ec with almost zero value. Therefore, it can be said that it is possible to confirm that a reliable cut shape of the material to be cut has been obtained by detecting and determining the cutting current during cutting. In the present invention, by detecting and evaluating the state in which the current value continues for several tens of m8 during cutting, the cutting state of the material to be cut can be confirmed, and if a state in which cutting is not possible occurs, the device automatically This is a control method to automatically stop the cutting conditions, repair the cutting conditions, and start cutting again.

[Embodiments of the invention]

Hereinafter, an embodiment of the cutting control method of the highly radioactive solid waste volume reduction device of the present invention will be described. The same parts as in FIG.
The explanation of No. 4 construction will be omitted and will be explained with reference to FIGS. 2 and 3.

FIG. 2 is an overall perspective view, and FIG. 3 is a sectional view taken along the line -■ in FIG. 2.

Highly radioactive solid waste generated from nuclear reactors can be efficiently stored and reduced in the limited space inside the reactor building.
Since the waste is highly radioactive, a highly radioactive solid waste volume reduction device using a water-jet cutting method is used to carry out remote cropping underwater. In the figure, 10 is a cutting torch, 11 is a jet water supply nozzle, 12 is a wire guide, 13 is a cart drive shaft, and 14
is a ball screw, 15 is a guide, and 16 is an upper and lower cart connected by several guides 15, etc.)2
0.21, and is driven to move vertically by a cart drive shaft 19. 17 is a dross collection box, and 1B is an operation panel. In this embodiment, the material 5 to be cut is a square tube, and in order to eliminate the space inside the square pipe and reduce its volume when stored, the opposing corners are connected to the cutting torch 10, respectively, as shown in FIG. This is a material that is cut into many angles.

Highly radioactive solid waste (hereinafter referred to as materials to be cut) generated in the nuclear reactor is collected by remote control from the primary storage area of the pool inside the reactor building.
The container is transported underwater in a trench (referred to as a lower volume reduction device) and fixed to an upper and lower cart 16 pushed down to the lower end of the volume reduction device. In this state, the upper and lower carts 16 are moved to the upper limit by the cart drive mechanism 19 via the ball screw 14 and the cart drive shaft 13 to set a state in which cutting of the material 5 to be cut can be started. In this state, first, high aqua regia is jetted out through the jet water supply pipe 11, and then, by driving the wire feed motor 8, the stain electrode wire 2 is passed from the cutting torch 10 through the wire guide 12 to the material to be cut 5. supply to When this electrode wire 2 comes into contact with the material to be cut 5, an arc discharge is generated between the two, and the material to be cut 5 and the electric wire 2 are simultaneously melted. Further, the material to be cut 5 is cut by blowing away the melted portion through high-pressure water supplied from the tip of the cutting torch 10 through the jet water supply pipe 11. These series of operations are performed by an operator remotely operating a control panel 18 provided at the top of the volume reduction device. The material to be cut 5 is driven to move downward together with the upper and lower carts 16 at a constant speed during cutting.

In this cutting operation, the cutting torch 10 and the material to be cut 5
Even if the distance dimension of the vertical car 116, which moves up and down with the cutting torch 10 fixed, is constant, the workpiece 5
The distance relationship between the cutting torch 10 and the material to be cut 5 may not necessarily be constant due to deformation of the cutting torch 10 and the material to be cut 5, and therefore, the cutting conditions by the electrode water jet cutting method will change somewhat. As a result, the arc discharge occurring between the electrode wire 2 and the material to be cut 5 may be temporarily interrupted or completely disappear. At this time, the upper and lower carts 16
In the conventional method in which the drive of the material 5 is continued, the cutting shape of the material 5 to be cut may be an interrupted staggered shape, or some uncut portions may remain continuously, which may result in cutting the material 5 that was not intended for the initial purpose. Therefore, it becomes impossible to efficiently reduce the volume of the material to be cut 5. In this case, it is necessary to take measures to re-cut the uncut part, but in this case, the distinction between the cut part and the uncut part is as follows:
This is technically very difficult because the part 5 to be cut is placed underwater, and therefore requires complicated work.

In the event that such a malfunction occurs, in this embodiment, based on the matters confirmed in FIG. The current value is constantly monitored, and when the current value becomes zero or below a predetermined current value for a predetermined period of, for example, several tens of m8eO, the cutting operation of the device is automatically stopped, and the upper and lower carts 16 are Once the cutting torch 10 has been returned to the position of the cutting torch 10 in the direction opposite to the direction of movement of the upper and lower carts 16 at the time of cutting, the cutting is started again. The electrode wire 2 is sent out to the position of the cutting torch 10, and arc discharge is started again. Therefore, if a cutting failure occurs, it is extremely easy to deal with it. Figure 5 shows the work flow chart in this case. That is, the arc current is constantly monitored, and when a fluctuation occurs and a cutting defect is detected, the feeding roller 1 of the electrode wire 2 is stopped, and the drive motor that drives the movement of the material to be cut 5 is stopped, and the movement of the material to be cut 5 is stopped. After the cutting is stopped and the material to be cut 5 is fed backwards, discharge cutting is started again, and thereafter this is not repeated automatically but is carried out by a device (not shown). Therefore, cutting defects caused by the shape of the material to be cut can be eliminated without bothering the operator, and the cutting operation can be performed reliably by remote control without having to be in close proximity.

As described above, it has been experimentally confirmed that the cutting control method of the highly radioactive solid waste volume reduction device of this example can detect unstable cutting conditions by checking the current fluctuation status.
When the current is detected and unstable cutting occurs, that is, there is a cutting failure, the cutting operation is temporarily stopped and the material to be cut is returned to the position of the electrode wire where the cutting failure started, so that the electric discharge is performed again. This prevents cutting defects such as uncut parts due to the shape of the material to be cut, ensuring reliable cutting, eliminating downtime, saving labor, significantly reducing work man-hours, and reducing radiation exposure. The reliability of the work can also be improved.

〔Effect of the invention〕

As described above, according to the cutting control method of the highly radioactive solid waste volume reduction apparatus of the present invention, even if the material to be cut has deformed shape or other deformation, it can be cut smoothly and efficiently, and the number of work steps can be significantly reduced. It is something that has fruit.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an apparatus for carrying out a conventional solution-type water jet cutting method, and FIG. 2 is a perspective view of an apparatus for carrying out a cutting control method for a highly radioactive solid waste volume reduction apparatus according to the present invention. Fig. 3 is a sectional view taken along the ■-m arrow in Fig. 2, Fig. 4 is a current and voltage characteristic diagram of the device shown in Fig. 2 when it is turned off, and Fig. 5 is a diagram of the current and voltage characteristics when the device shown in Fig. 2 is cut. It is a work flow chart. DESCRIPTION OF SYMBOLS 1... Feed m roller, 2... Electrode wire, 5... Broken material, 6... Nozzle. Agent Patent attorney Hiroo Nagasaki (and 1 other person) No. 1 Kokui Dan/'\ 23 Figure 1

Claims (1)

[Claims] 1. Highly radioactive solid waste material to be cut that is driven to move in a predetermined direction, and high-pressure water jetted from a nozzle to melt the part of the material to be cut by arc discharge in the moving direction of the material to be cut. In the molten-type quarter-jet arc cutting method, in which the current during the arc discharge is detected and the current becomes zero or below a predetermined current value for a predetermined period of time, the cutting operation is temporarily stopped. At the same time, the material to be cut is moved back to the position of the electrode wire relative to the cutting direction to start electric discharge again, and the highly radioactive solid is controlled so that these operations are performed automatically. Cutting control method for waste volume reduction equipment.