JPH0651097A - Method and device for washing internal wall surface of isolation space - Google Patents

Abstract

PURPOSE:To simply and safely wash the inner wall surface of an isolated space using a liquid which less influences the criticality. CONSTITUTION:The bottom surface 2 of a globe box 1 is provided with a taper so that the detergent flows easily. The detergent is spouted from a nozzle 7 on a pipe 6 toward the panel surface of the globe box 1. The inside of the globe box 1 is always exhausted, and the exhaust air flows through filters 8, 8' to the exhausting facility 9 of the equipment concerned. The dust and dirt scraped off from the panel surface by the detergent is carried thereby as creeping over the bottom surface 2 of the globe box and gathers at its lowest part. In this process, the detergent is gasified, passes through the filters 8, 8' together with the exhaust air, and is liquefied by a liquefying/collecting device 12. A vacuum pump 17 is started after the detergent is completely evaporated, and the dust and dirt are collected into a dust container 16.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a nuclear fuel facility,
Cleaning method and device for removing dirt adhering to the inner wall surface that partitions the space isolated from the outside, such as glove boxes, tower tanks, sampling boxes, etc. used in nuclear facilities such as nuclear fuel reprocessing facilities Regarding

[0002]

2. Description of the Related Art For example, a glove box is used when performing various operations in nuclear facilities such as nuclear fuel facilities and nuclear fuel reprocessing facilities. This glove box is used for handling nuclear fuel materials and the like in a sealed state isolated from the outside world, is a box-shaped container, and has a ceiling surface,
The bottom is made of stainless steel and the sides are made of transparent resin panels. Rubber gloves are attached to various parts of the panel, and hands are inserted into the gloves to operate internal devices and equipment. For example, in order to process a nuclear fuel material into a nuclear power plant fuel, it is necessary to perform melting, preparation, drying, granulation, roasting reduction, polishing shaping, measurement, assembly, etc., but these devices and equipment are required. It is provided in this glove box accordingly. As a result, oil dust such as processing dust, dust, powder, and grease is generated with the operation, and the panel surface is gradually clouded and the visibility is obstructed. Therefore,
The panel surface must be cleaned from time to time to ensure visibility within the glove box.

Further, among these devices and equipment, nuclear fuel substances and the like may adhere to column tanks such as cyclone dust collectors and powder mixers that handle nuclear fuel substances, or inner wall surfaces of sampling boxes and the like. In order to ensure the functions of these devices, it becomes necessary to remove the deposits on the inner wall. Conventionally, the dirt adhering to the panel surface of the glove box is manually wiped off with a glove. Further, tower tanks and sampling boxes are opened or disassembled, and manually wiped or washed.

[0004]

However, the work of wiping the glove box takes a long time, and there is a risk of exposure of the worker. Moreover, since the waste cloth used after the cleaning becomes radioactive waste, there is a drawback that a large amount of radioactive waste is generated. It is possible to use pure water, alcoholic water, or the like for the wiping, but since the influence of the nuclear material on the criticality becomes a problem, it is desirable to use a cleaning liquid that does not affect the criticality. Also, due to the use of the towers and sampling boxes used in the nuclear fuel reprocessing facility, nuclear fission products as well as nuclear fuel materials are accumulated inside. This fission product emits beta rays and gamma rays, raises the external dose, and increases the external exposure of humans during operation.Therefore, decontamination work will be performed from time to time to reduce the external dose. However, this decontamination work has a drawback that it causes exposure and generation of waste.

Therefore, in view of the problems of the conventional technique for cleaning the inner wall surface of the isolated space, the present invention cleans the inner wall surface of the isolated space simply, safely, and using a cleaning liquid that has little effect on the criticality of the nuclear material. The purpose is to enable.

[0006]

That is, according to the present invention,
In order to achieve the above-mentioned object, in a cleaning method for removing dirt adhering to an inner wall surface that divides a space isolated from the outside used in a nuclear facility, a cleaning liquid having a small influence on the inner wall surface is injected. Provided is a method for cleaning an inner wall surface of an isolated space, characterized in that the dust and dirt removed together with the cleaning liquid are collected at a low position on the bottom surface of the space, and the collected dust and dirt are separated from the cleaning liquid and collected. Furthermore, in a cleaning device used in a nuclear facility for removing dirt adhering to an inner wall surface that separates an isolated space from the outside, a cleaning liquid having a small influence on criticality is sprayed toward the outer wall toward the inner wall surface. And a bottom wall surface of the space where a low portion is formed to collect the cleaning liquid at a predetermined location, and a means for separating dust and dirt collected on the bottom wall surface from the cleaning liquid. An apparatus for cleaning an inner wall surface of an isolated space, comprising: a cleaning liquid and means for collecting separated dust and dirt.

[0007]

For example, the part of the glove box or the like which is isolated from the outside and needs to remove dirt is mainly the panel part. Although it depends on the device and equipment installed in the space, this dirt and dust scatter from the device and equipment, rise up and adhere to the inner wall surface. Therefore, these dusts and dirts are not firmly adhered, and can be washed with an appropriate washing liquid, for example, to the extent that the visibility of the panel is secured. In the present invention, the cleaning liquid is sprayed onto the inner surface of the panel of the glove box, and an injection nozzle is provided in the glove box toward the panel surface so that the cleaning can be performed.

The dust and dirt washed with the washing liquid is deposited on the bottom of the space. After the cleaning liquid for cleaning evaporates and the dust and dirt are dried, the deposit is sucked and collected by a vacuum cleaner or the like provided in the glove box. In order to facilitate this recovery, a part of the bottom surface is formed to be low so that the deposits gather at one place on the bottom surface. For example, the bottom surface of the glove box may be inclined so that the cleaning liquid is collected at one place, or a rain-dough-like groove is provided under the panel of the glove box. Further, the vaporized gas of the cleaning liquid used can prevent environmental pollution and can economically use this cleaning liquid, so that it is possible to attach a liquefaction recovery device.

Washing of dust and dirt of radioactive materials such as nuclear fuel materials and fission products in tower tanks and sampling boxes,
The removal can be performed by the same method as in the case of the glove box, but in this case, it is not for ensuring the visibility but for preventing the deterioration of the function of the device and equipment due to the adhesion of dust and dirt of these radioactive substances, and the radioactive substances. The purpose is to prevent an increase in external dose due to the accumulation of It is also possible to separate the cleaning liquid and the dust and dirt by separating the cleaning liquid as a drain together with the cleaning liquid without separating from the cleaning liquid in the tower tanks and the sampling box, and then evaporating and vaporizing the cleaning liquid.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. A glove box, which is a typical example of a space that is isolated from the outside world,
It can be roughly divided into two types according to the devices and equipment handled inside. One is a glove box for dissolution, preparation, drying, and granulation processes, the inside of which is an aqueous solution (nitric acid) atmosphere (hereinafter referred to as "wet glove box"), and the other is roasting reduction, polishing shaping, The glove box used in the measurement and assembly process has a dry atmosphere or an atmosphere of oil stains such as grease (hereinafter referred to as "dry glove box"). In cleaning the panel surface, the inside of the wet glove box is first dehumidified and dried with dry warm air or the like. The dry glove box does not require such a drying step, and thereafter, the wet and dry processes are similarly performed.

In FIG. 1, 1 is a glove box,
A slope is formed on the bottom surface 2 so that the cleaning liquid can easily flow, and a part thereof is lowered. 3 is a container for containing the cleaning liquid 4, and 5 is a pump for transferring the cleaning liquid 4. Reference numeral 6 is a pipe for injecting the cleaning liquid into the glove box, and the nozzles 7 are opened at appropriate intervals toward the side panel surface. The glove box 1 needs to be maintained at a negative pressure at all times so as not to leak nuclear fuel substances to the outside, and therefore the inside of the glove box 1 is constantly exhausted. This exhaust gas flows to the exhaust equipment 9 (not shown) of the facility through the filters 8 and 8 '. The cleaning liquid sprayed into the glove box 1 is evaporated and vaporized in the box 1, and the exhaust flows together with the exhaust through the filters 8 and 8'to the exhaust equipment 9 side of the facility. Reference numeral 12 is a liquefaction recovery device that recovers the cleaning liquid 14 on the way, and 13 is a decomposition and detoxification device.

On the other hand, outside air enters the glove box 1 through the filter 10. In the case of a wet glove box, the dry hot air generator 11 for dehumidifying and drying the inside as described above is added. Further, the liquefaction recovery device 12 for the vaporized gas of the cleaning liquid is inserted and installed between the exhaust filter 8'and the exhaust equipment 9 of the facility. However, even if a liquefaction recovery device is used, it is difficult to complete recovery,
A device 13 for decomposing and detoxifying vaporized gas is also installed. The cleaning liquid 14 is recovered by liquefaction and can be used again as the cleaning liquid of 4. Denoted at 15 is dust and dirt collected as a result of cleaning, which is collected in the dust container 16. Reference numeral 17 is a vacuum pump used for dust collection.

Because of the above structure, in order to collect dust and dirt in the glove box 1, first, in the case of a wet glove box, the dry hot air generator 11 is operated for an appropriate time, and the inside To dry. Note that this is not necessary for dry glove boxes. Next, the cleaning liquid 4 is put into the container of 3, the transfer pump 5 is operated, and the injection pipe 6
Spray the cleaning liquid 4 from the nozzle 7 to the panel surface through
To wash. At the same time, the liquefaction recovery device 12 and the vaporized gas decomposition / detoxification device 13 are activated. The dust and dirt is carried by the cleaning liquid, flows through the bottom surface 2 of the glove box 1, and collects at the lowest portion thereof. In this process, the cleaning liquid is vaporized and passes through the filters 8 and 8 ′ together with the exhaust gas, and most of it is liquefied in the liquefaction recovery device 12. The vaporized gas that could not be collected here is removed by the decomposing / detoxifying device 13 and the exhaust gas flows to the exhaust equipment 9. Cleaning solution is glove box 1
After completely evaporating from the inside, the vacuum pump 17 is activated to collect dust and dirt in the dust container 16.

A solution of a mixture of kerosene and a fluorescent paint was applied to a metal test piece and dried, and it was considered that dust and dirt such as a glove box adhered, and the nozzle diameter:
0.5 mm, injection shape: fan-shaped with an opening angle of 15 degrees, injection pressure: 60-80 kg / cm ² Amount of cleaning liquid used: about 1 liter per minute, and the panel surface of the glove box was subjected to the above method. Washed. As a result of performing this test twice, the stainless steel surface buffed
Almost no fluorescent paint remained on the metal test piece as confirmed by UV irradiation. This is in agreement with the metal part of the glove box, other tower tanks, the material of the sampling box, and the surface finish condition, and the effect is judged to be great. Further, the panel surface can be regarded as being equivalent to the above surface finish, and the same effect can be expected.
The cleaning liquid used here was Freon 113 (trichlorotrifluoroethane). Since the use of specific CFCs will be prohibited in the very near future, an alternative CFC for cleaning has been developed to replace it, but in the present invention, this CFC alternative can be used.

Next, FIG. 2 shows an example in which the present invention is applied to tower tanks. In the figure, 18 is a tower tank main body, and an annular cleaning liquid transfer pipe 22 is installed inside thereof, and nozzles 2 are provided on both sides thereof toward the inner wall surface of the tower tank main body 18.
3, 23 are open. 19 is a container for containing the cleaning liquid 20, and 21 is the cleaning liquid 2 to the cleaning liquid transfer pipe 22.
It is a transfer pump that sends out 0. Reference numeral 24 is a cleaning liquid discharge valve containing dust and dirt, and 25 is a dust and dirt collection container.
The exhaust system 26 connected to the dust and waste collection container 25 is the same as that of the exhaust filter 8 and the subsequent parts in FIG. 1, and the illustration thereof is omitted. This embodiment is different from that of FIG. 1 in that the cleaning liquid containing dust and dirt is once received by the recovery container 25, and the dust and dirt are separated from the cleaning liquid here.

Next, FIG. 3 shows an example in which the present invention is applied to a sampling box. In the figure, 27 is the sampling box body (shielding structure), and 28 is its internal observation window. 29 is a sampling box body 27
Reference numeral 30 is a sampling pipe introduced therein, and 30 is a sampling valve thereof. 31 is a sampling pipe 29
Is a sample sampling container for receiving a sample from, and 32 is a lid of the sampling container 31. Further, an annular cleaning liquid transfer pipe 36 is installed inside the sampling box main body 27, and nozzles 37, 37 are opened on both sides thereof toward the inner wall surface of the sampling box 27. 33 is a container for containing the cleaning liquid 34,
Reference numeral 5 denotes a transfer pump for sending the cleaning liquid 37 to the cleaning liquid transfer pipe 36. Numeral 38 is a cleaning liquid discharge valve containing a radioactive substance and the like, and 39 is a container for collecting the radioactive substance and the like. The exhaust system 40 connected to the radioactive substance recovery container 39 is the same as that of the exhaust filter 8 and subsequent parts in FIG. 1, and the illustration thereof is omitted.

[0017]

As described above, according to the present invention, the inner wall surface of the isolated space can be cleaned easily, safely, and with the use of the cleaning liquid which has a small influence on the criticality of the nuclear material.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example in which the present invention is applied to cleaning a panel surface of a glove box.

FIG. 2 is a schematic view showing an example in which the present invention is applied to cleaning inner wall surfaces of tower tanks.

FIG. 3 is a schematic view showing an example in which the present invention is applied to cleaning the inner wall surface of a sampling box.

[Explanation of symbols]

 1 glove box 2 bottom of glove box 3 container for containing cleaning liquid 5 cleaning liquid transfer pump 6 cleaning liquid transfer pipe 7 injection nozzle 8 exhaust filter 8'exhaust filter 12 cleaning liquid liquefaction recovery device 16 dust and dirt recovery container 17 vacuum pump

Claims (2)

[Reference number] 0920108-02 [Claims] 1. In a cleaning method for removing dirt adhering to an inner wall surface for partitioning a space isolated from the outside used in a nuclear facility, a cleaning liquid having a less critical effect on the inner wall surface is sprayed, and together with the cleaning liquid. A method for cleaning the inner wall surface of an isolated space, characterized in that the removed dust and dirt are collected at a low position on the bottom of the space, and the collected dust and dirt are separated from the cleaning liquid and collected. 2. A cleaning device used in a nuclear facility for removing dirt adhering to an inner wall surface that separates a space isolated from the outside, so that a cleaning liquid having a less critical effect on the inner wall surface is injected. A nozzle installed in a space isolated from the outside, a bottom wall surface of the space where a low portion is formed to collect the cleaning liquid at a predetermined location, and dust and dirt collected on the bottom wall surface are separated from the cleaning liquid. Means to do
An inner wall surface cleaning device for an isolated space, comprising: a cleaning liquid and a means for collecting separated dust and dirt.