JPH0530159Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application" The present invention relates to a decontamination device developed for decontaminating the side walls of closed cells installed in nuclear thermal processing facilities and the like.

"Prior Art" The sealed cell is a device provided to safely perform processes such as cutting, dissolving, and transferring highly radioactive materials such as spent nuclear fuel into containers for transportation. The structure is such that a manipulator that handles radioactive materials contained in the room or an in-cell crane that transports items is installed in a sealed room surrounded by a radiation shielding wall.

``Problem that the invention aims to solve'' By the way, when work such as transferring radioactive materials from one container to another in the above-mentioned closed cell is carried out, radioactive dust, etc. is scattered around, and the walls of the closed cell, the floor, etc. It tends to gradually adhere to the If radioactive dust, etc. accumulates over a long period of time and the dose inside the cell becomes extremely high, for example, if a worker needs to enter the cell for maintenance or inspection, the radioactive material So-called decontamination work will be required to remove such substances.

Conventionally, for the purpose of decontamination, cleaning equipment has been used that sprays water on the cell walls to wash away radioactive dust, etc., but there are limits to physical cleaning using the kinetic energy of the fluid. There is.

Therefore, it is conceivable to have a manipulator installed in the cell hold an instrument such as a brush to scrub the inner surface of the cell, but there is a limit to the operating range of the manipulator. For example, although it is possible to clean the surface facing the wall to which the manipulator is attached, it is difficult to clean the wall to which the manipulator is attached.

This idea was proposed in view of the above circumstances.
It is an object of the present invention to provide a cleaning device capable of cleaning the wall surface of a cell that handles radioactive materials, particularly the wall outside the operating range of a manipulator.

"Means for Solving Problems" In order to achieve the above object, the present invention provides a horizontal arm in the suspension mechanism of an in-cell crane installed in a sealed cell that handles radioactive materials, etc., and attaches a horizontal arm to one end of the horizontal arm. An electrode that is brought into contact with the wall surface of the cell through an electrolyte holding layer and a wiping tool that absorbs the electrolyte supplied to the wall surface from the electrolyte holding layer are protrudingly provided on the supported frame, and the horizontal A counterweight is provided at the other end of the arm to apply a rotational moment to the horizontal arm and press the electrode and wiping tool toward the wall surface, and the suspension mechanism is moved vertically or horizontally to electrolyze the wall surface. It is designed to perform polishing.

"Embodiment of the invention" Hereinafter, an embodiment of the invention will be described with reference to FIGS. 1 to 6.

Reference numeral 1 in FIG. 1 is a suspension mechanism. This lifting mechanism 1 is a so-called in-cell crane (or hoist), and is supported by a crane beam 2 provided within the cell and moves in the horizontal direction (in the direction perpendicular to the plane of the paper in Fig. 1 and in the left-right direction). It also has the function of lifting the article by moving the hook 3 up and down.

A horizontal arm 4 is supported by the suspension mechanism 1, and a frame 5 is attached to one end of the horizontal arm 4.
is provided vertically downward. A polishing mechanism 6 is attached to the lower end of the frame 5, and the polishing mechanism 6 moves integrally with the frame 5 while in contact with the cell wall surface W to perform polishing.

The polishing mechanism 6 includes an electrode 7, a wiping tool 8, and a guide ring 9.

As shown in FIGS. 2 and 3, the electrode 7 includes an electrode plate 10 made of a conductor (for example, stainless steel) that is connected to a power supply (not shown), and a distal end of the electrode plate 10 that covers the electrode plate 10. The electrolyte holding layer 11 is provided along with the electrolyte holding layer 11. The electrolyte holding layer 11 is composed of a water-containing body 12 made of a material such as cotton cloth or sponge, and a cover 13 that covers the water-containing body 12. The cover 13 prevents the electrolyte from generating heat during electrolytic polishing. It is made of a material that protects the holding layer 11 and allows the electrolyte to pass therethrough, such as glass fiber cloth. Further, the electrolyte electrode plate 10 is vertically rotatably supported by the frame 6 via a shaft 14, and is connected to a power supply device (not shown) via a connection cable 15. A stopper (not shown) is provided at the base end of the electrode plate 10 to support the electrode plate 10 from below and direct it diagonally upward as shown in FIG.

The wiping tool 8 has a shaft 1 attached to the lower end of the frame 5.
Support bar 1 supported vertically rotatably via 6
7 and a water absorption layer 18 provided at the tip of the support bar 17.
is formed of an electrically insulating material such as wood, while the water-absorbing layer 18 is formed by covering a water-containing body 19 made of a material such as sponge with a cover 20 such as cotton cloth, and sewing the cover 20 into a bag shape. It has a structure. Further, the support bar 17 is also provided with a stopper (not shown), and is adapted to be directed diagonally upward as shown in FIG.

Furthermore, the frame 5 has a structure that can be divided via a joint 21 provided in the middle thereof,
Furthermore, a joint 22 is also provided between the horizontal arm 4 and the frame 5 so that they can be separated. Further, both the joints 21 and 22 are provided with handles 23 in consideration of operability by a manipulator, and are adapted to be attached and detached by operating the handles 23.

On the other hand, a counterweight 24 is provided at the other end of the horizontal arm 4. The counterweight 24 is composed of a support part 25 and a weight body 26 that is detachably attached to the support part 25.
5, the horizontal arm resists the rotational moment (counterclockwise rotational moment about the fulcrum 0 in FIG. 1) applied to the horizontal arm 4 from the frame 5, electrode 7, wiping tool 8, etc. The arm 4 is biased in the opposite direction to achieve balance.

The electrolytic polishing apparatus configured as described above performs electrolytic polishing of the wall surface W in the following manner.

(i) The horizontal arm 4 is suspended from the suspension mechanism 1 at a position away from the wall surface W, and the counterweight 24 is adjusted so as to balance the horizontal arm 4 horizontally.

(ii) Move the suspension mechanism 1 to the left side in FIG. 1, and bring the electrode 7 and the wiping tool 8 into contact with the wall surface W. At this time, the guide ring 9 comes into contact with the wall surface W, so that the distance between the frame 5 and the wall surface W is maintained.
Furthermore, the electrode 7 and the wiping tool 8 are pressed against the wall surface W by the gravity acting on each. In addition, the electrode 7 and the wiping tool 8 are removed from the wall surface W.
If these tend to separate from the wall surface W due to a reaction acting on the counterweight 2,
What is necessary is to add No. 4 weight body 26.

(iii) When the wall W and the electrode 7 are connected to the anode and cathode of a power source (not shown), and the frame 5 is moved up and down by the suspension mechanism 1, the electrode plate 10 and the wall W hold the electrolyte. Electricity is applied through the layer 11, and the surface of the wall W is electrolytically polished, and the electrolytic solution adhering to the wall W is absorbed by the water absorption layer 18 of the wiping tool 8. Furthermore, after the wall surface W is electrolytically polished in the vertical direction, the suspension mechanism 1 is moved in the horizontal direction (direction perpendicular to the paper plane of FIG. 1), and the above-mentioned electrolytic polishing is repeated. Note that the electrolytic solution is replenished into the electrolytic solution holding layer 11 as necessary.

(iv) After the electrolytic polishing over the entire surface of the wall W is completed, water is sprinkled on the wall W to wash away the remaining electrolyte.

In the electrolytic polishing apparatus described above, since the polishing mechanism 6 is provided at a position protruding from the suspension mechanism 1 in the horizontal direction, a so-called overhang portion (indicated by reference numeral 27 in FIG. 1) is formed on the wall surface W. Even if the electrode 7 and the wiping tool 8 are present, the electrode 7 and the wiping tool 8 can be brought close to the wall surface W. Therefore, the structure of the cell (presence or absence of overhang, size of protrusion)
It is necessary to set the length of the horizontal arm 4 as appropriate.

Note that by adding weight to the electrode 7 and the wiping tool 8, the contact pressure of these against the wall surface W can be increased. Further, the contact pressure against the wall surface W may be reduced by providing a counterweight to these.

Furthermore, the division locations of the electrolytic polishing apparatus are not limited to the one embodiment described above, but may be structured so that it can be divided into a larger number of parts depending on the volume and shape of the container used for disposal.

"Effects of the invention" As is clear from the above explanation, the invention provides a horizontal arm to the lifting mechanism of an in-cell crane or the like installed in a closed cell that handles radioactive materials, etc.
An electrode that is brought into contact with the wall surface of the cell through an electrolyte holding layer and a wiping tool that absorbs the electrolyte supplied to the wall surface from the electrolyte holding layer are horizontally protruded on the horizontal arm. Since a counterweight is provided at the other end of the horizontal arm to apply a rotational moment to the horizontal arm and press the electrode and wiping tool toward the wall surface, the operating range of the manipulator installed in the cell can be reduced. It is possible to decontaminate the wall surface that exists in the area that is crossed, and it also uses a suspension mechanism such as a crane installed inside the cell, and utilizes the linear movement function that this suspension mechanism inherently has. Since decontamination is carried out while moving, compared to using a manipulator,
This has the effect that decontamination work can be carried out quickly and efficiently.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is an overall side view, Fig. 2 is a perspective view showing the external appearance of the electrode plate, Fig. 3 is a vertical cross-sectional view of the electrode, and Fig. 4 is a support. FIG. 5 is a perspective view showing the appearance of the bar, FIG. 5 is a perspective view showing the appearance of the wiping tool, and FIG. 6 is a longitudinal sectional view of the wiping tool. DESCRIPTION OF SYMBOLS 1... Hanging mechanism, 4... Horizontal arm, 5... Frame, 6... Polishing mechanism, 7... Electrode, 8... Wiping tool, 9... Guide ring, 10... Electrode plate, 11...
... Electrolyte holding layer, 12 ... Water-containing body, 13 ... Cover, 14 ... Shaft, 16 ... Shaft, 17 ... Support bar, 18 ... Water-absorbing layer, 19 ... Water-containing body, 20 ...
Cover, 24...Counterweight.

Claims (1)

[Scope of utility model registration request] A vertically movable suspension mechanism is provided in a closed cell that handles radioactive materials, etc., a horizontal arm is provided on the suspension mechanism, and an electrolyte retaining layer is attached to the wall of the cell on a frame provided at one end of the horizontal arm. A wiping tool is provided protrudingly to absorb the electrolyte supplied from the electrolyte holding layer to the wall surface, and the other end of the horizontal arm is
A decontamination device for a side wall of a closed cell, characterized in that a counterweight is provided that applies a rotational moment to the horizontal arm and presses the electrode and the wiping tool toward the wall surface.