JPH0735899A - Method and facility for treating radioactive contaminated substance - Google Patents

Abstract

PURPOSE:To enhance the operating efficiency by dissolving a radioactive contaminated substance into molten glass, solidifying the glass, and subjecting the gassified components to off-gas treatment. CONSTITUTION:A radioactive contaminated substance Y is contained in an enclosed container 11A which is then carried, while being enclosed by means of a shutter plate 13a, closely to a molten glass tank 1. The container 11A is then turned over and a connecting port 12 is fitted over a throw-in port 10. Subsequently, a cover 10a is opened and the plate 13a is shifted laterally through the action of a throw-in means 13 and a contaminated substance Y is dropped freely into a molten glass X. The contaminated substance Y is dissolved and thermally decomposed with the glass fiber component melting as a material into the glass X and radioactive substance, e.g. heavy metals, and metals, e.g. iron, melting integrally into the glass X. Gas produced by thermal decomposition is discharged from the tank 1 and treated as off-gas. The glass X capturing the radioactive substance flows from a discharge port 8 through a flow down nozzle 9 into a lower glass containing vessel where it is cooled and solidified thus allowing efficient treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating radioactive contaminants and an apparatus therefor, and more particularly to a technique for melting solid contents in radioactive contaminants into molten glass.

[0002]

2. Description of the Related Art Radioactive substances or solid wastes (radioactive contaminants) contaminated with radioactive substances are subjected to volume reduction processing for storage and transportation, and then sealed in storage containers. .

When the solid waste (radioactive pollutant) is a filter or the like, as a means for compressing and reducing the volume, an actual Kaihei 6
The techniques disclosed in Japanese Patent Laid-Open No. 3-154100 and Japanese Utility Model Laid-Open No. 63-163493 are proposed.

On the other hand, when the radioactive contaminant is a high-level liquid waste, the high-level liquid waste is sent together with the glass raw material into a melting furnace to melt the radioactive substance into the molten glass and solidify it. Is performed. As such a technique, for example, glass melting furnaces of JP-A-4-161896 and JP-A-4-161897 have been proposed.

[0005]

However, in the former method of compressing and reducing the volume of solid waste, since it is a porous material, it is possible to perform sufficient compression and reduction by the amount of air. Since it is difficult and the apparent bulk becomes large, the construction cost of the storage facility separated from the living area increases. With the latter method of vitrifying,
Although it is sufficient in terms of hermeticity, the application of the glass melting furnace is mainly limited to only high-level waste liquid, and there remains a problem that operating efficiency is reduced.

The present invention effectively solves such a problem. That is, the purpose is to dramatically increase the volume reduction rate of radioactive pollutants and to improve the overall operation efficiency such as vitrification.

[0007]

[Means for Solving the Problems] Several means for solving the problems are proposed. The first means is a step of introducing the radioactive contaminant into the molten glass, a step of vitrifying the radioactive contaminant dissolved in the molten glass, and an off gas of the gasified component in the radioactive contaminant. The method for treating radioactive contaminants comprises the step of treating. The second means is a method for treating radioactive contaminants, in which the step of alkalizing the radioactive contaminants in advance is added to the first means. A third means is a closed container for containing radioactive contaminants, a connection port arranged in the closed container and connected to a glass melting tank, and a radioactive contaminant disposed in the connection port inside the glass melting tank. And a charging means for transferring the radioactive contamination to the radioactive contamination processing apparatus. A fourth means is to install a granular radioactive contaminant in a closed container which is installed in an inverted state when the radioactive contaminant is transferred into the glass melting tank and an upper opening of the sealed container. Of the radioactive contaminants having a connecting port, a hopper arranged in the opposite direction to the connecting port, and an opening / closing means arranged at the outlet of the hopper to allow passage of the radioactive contaminants when opened. It is used as a processing device. The fifth means is a device for treating radioactive contaminants, which is added to the fourth means, in which an air feeding means for transferring granular radioactive contaminants to the glass melting tank is connected to the closed container. .

[0008]

In the first means, when radioactive contaminants are introduced into the molten glass, the glass fiber components in the radioactive contaminants are melted and mixed with the molten glass, and The radioactive substance and the like inside is melted into the molten glass, and the radioactive substance can be concentrated and vitrified. That is, glass fiber and silica gel, which are radioactive contaminants, are used for vitrification, the addition of extra glass raw materials is reduced, and the total amount of radioactive waste is reduced. Then, the gasification component generated by the thermal decomposition of the radioactive contaminants is discharged as off-gas and processed. In the second means, in addition to the action of the first means, by pre-alkalizing the radioactive contaminants, the production of metal oxides is hindered and the radioactive contaminants are contained in the radioactive contaminants. The transfer of volatile substances such as ruthenium oxide to off-gas is suppressed. In the third means, the closed container containing the radioactive contaminants is connected to the glass melting tank, and the radioactive contaminants are transferred from the connection port to the inside of the glass melting tank by the operation of the charging means. However, the radioactive contaminants are dissolved and pyrolyzed. In the fourth means, when the radioactive contaminants are granular, the hopper and the connection port are arranged at the upper opening of the closed container containing the radioactive contaminants, and the sealed container is turned upside down. The connection port is attached to the glass melting tank by opening the connection port by operating the opening / closing means to allow the radioactive contaminant to flow down into the glass melting tank, whereby the radioactive contaminant is dissolved and pyrolyzed. In the fifth means, in addition to the operation of the fourth means, the radioactive contaminants are fluidized by the operation of the air feeding means and transferred to the inside of the glass melting tank to be supplied.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and apparatus for treating radioactive contaminants according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of a radioactive pollutant treating apparatus for treating radioactive pollutants.
Reference numeral 1 is a glass melting tank, 2 is a side wall, 3 is an electrode, 4 is a bottom wall, 5 is a bottom electrode, 6 is a ceiling wall, 7 is a raw material supply port, 8 is a discharge port, 9 is a downflow nozzle, and 10 is a charging port. , 11A is a closed container, 12 is a connection port, 13 is a charging means, X is a molten glass (melt), and Y is a radioactive contaminant.

The radioactive contaminant Y is, for example, a mist filter or a HEPA filter (particularly an element portion to which the radioactive substance is attached) for capturing the radioactive substance contained in the mist discharged from the concentrator, In the example of FIG. 1, it is applied to a solid and columnar one.

At the portion of the ceiling wall 6 of the glass melting tank 1, a raw material supply port 7 and an input port 10 are arranged so as to connect the inside and the outside. An opening / closing lid 10a which is opened / closed by remote control is arranged at the portion of the input port 10.

The airtight container 11A has a radioactive contaminant Y contained therein, and a connection port 12 for connecting to the charging port 10 is provided at the opening. And connection port 1
2 is provided with a charging means 13 for closing the opening to make the inside airtight and transferring the radioactive contaminant Y toward the inside of the glass melting tank 1 if necessary.

The connection port 12 is, as shown in FIG.
By setting the closed container 11A upside down and combining it with the insertion port 10, it is set to be in the engaged state.

The charging means 13 is arranged in the vicinity of the connection port 12, and is a shutter plate for preventing the free fall of the radioactive contaminant Y in a state where the opening of the closed container 11A is always closed and the top and bottom are turned upside down. 13a and the shutter plate 1
A guide portion 13b for guiding the horizontal movement of 3a, a drive motor 13c arranged near the guide portion 13b, and an intervening state arranged between the shutter plate 13a and the drive motor 13c, when the drive motor 13c operates. A rack for horizontally reciprocating the shutter plate 13a.
It has a pinion mechanism 13d.

An example of processing by such a radioactive contaminant processing apparatus will be described below.

[Sealing and Transport of Radioactive Contaminants] In a mist filter, a HEPA filter or the like, solid-state waste that has been activated by adsorbing a radioactive substance, that is, the radioactive contaminant Y is stored in the closed container 11A. It is housed inside, is held in a sealed state by the shutter plate 13 a in the charging means 13, and is conveyed to the vicinity of the glass melting tank 1.

[Connection of Glass Melting Tank and Airtight Container] FIG. 1
As shown in FIG. 5, the closed container 11A is turned upside down, and the connection port 12 is put on the insertion port 10 to be connected to each other. In this upside down state, the radioactive contaminant Y falls freely due to its own weight, but the shutter plate 1
Supported by 3a.

[Transfer Supply of Radioactive Contaminants] With the opening / closing lid 10a of the charging port 10 in the glass melting tank 1 opened as shown in FIG. 1, the shutter plate 13a is laterally displaced by the operation of the charging means 13. Then, the radioactive contaminant Y freely falls and is charged into the molten glass X in the glass melting tank 1 via the charging port 10.

[Melting and Thermal Decomposition of Radioactive Contaminant] The radioactive contaminant Y that has been put into a molten and pyrolyzed state when heat is supplied from the molten glass X. When the glass fiber component is contained in the radioactive contaminant Y, it is supplied to the molten glass X as a glass material. When a radioactive substance such as a heavy metal is adsorbed on the filter, or when a metal such as iron is mixed, the filter is melted by the heat of the molten glass and is also melted into the molten glass. Gas and volatile components generated by thermal decomposition of the radioactive contaminant Y are discharged from the glass melting tank 1 and treated as off-gas.

[Glass Solidification Treatment] The molten glass X that has been concentrated by incorporating a radioactive substance is made to flow down from the discharge port 8 through the flow-down nozzle 9 into the glass storage container that has been kept waiting below. The solidified glass is obtained by storing in a glass container and cooling.

Next, a second embodiment of the apparatus for treating radioactive contaminants according to the present invention will be described with reference to FIGS. 2 and 3. 2 and 3, reference numeral 11B indicates a closed container, 1
4 is a hopper, and 15 is an opening / closing means.

In FIGS. 2 and 3, the radioactive contaminant Y to be treated is a granular material such as silica gel. Even in this case, the connection port 12 is arranged in the closed container 11B, but the hopper 14 in the opposite state between the closed container 11B and the connection port 12 and the opening / closing of the air-operated valve or the like that can be remotely operated. Means 15 are provided.

In detail, if the silica gel adsorber (filter) 16 as shown in FIG.
6a is removed, and a filter element 16c containing silica gel having a radioactive substance adsorbed therein is contained in a container 16b.
3B, the fishing rod 16d and the mesh material 16e arranged on the filter element 16c are removed to remove the silica gel layer (radioactive contaminant) Y.
Open the upper part of the
Used as B.

That is, as shown in FIG. 3C, the connection port 12 for connecting to the charging port 10 of the glass melting tank 1 is attached to the upper part of the closed container (element case) 11B. And between the connection port 12 and FIG.
In the state shown in (c), the reverse hopper 14 and the opening / closing means 15 are attached in an interposing state, and the closed container 1
A lid, a hanger, etc. are appropriately attached to the lower portion of 1B to seal the radioactive contaminant Y.

As shown in FIG. 2, the closed container 11B and the like are placed in the glass melting tank 1 as shown in FIG. When 15 is opened, the sealed radioactive contaminant Y such as silica gel flows down into the glass melting tank 1 and is melted and thermally decomposed by the heat of the molten glass X, so that the silica content, the heavy metal, etc. are melted in the molten glass. Will be taken into account. Less than,
The molten glass X and the off gas are processed according to the first embodiment.

FIG. 4 shows a third embodiment of the apparatus for treating radioactive contaminants according to the present invention, which is applied when the radioactive contaminant Y is silica gel adsorbing a radioactive substance.

In the example of FIG. 4, reference numeral 17 is pneumatic means, 1
8 is a silica gel supply system, 19 is a mixing section, 20 is a storage hopper (closed vessel), and 21 is an offgas treatment system. Then, by the operation of the air feeding means 17, the silica gel supply system 1
The granular silica gel from No. 8 is fluidized in the mixing section 19 and sent into the storage hopper 20 for temporary storage. The gas, such as air, used for this air feeding is sent to the off-gas processing system 21 and processed.

The radioactive contaminant Y stored in the storage hopper 20 is supplied to the inside of the glass melting tank 1 by opening the opening / closing means 15 at an appropriate time according to the operating state of the glass melting tank 1. The above process is performed.

On the other hand, FIG. 5 shows an example of steps of a method for treating radioactive contaminants (objects to be treated) using a glass melting furnace. S1: Supply of an object to be processed and S2: Supply of an alkaline solution such as NaOH to add alkali to the object to be processed to make it alkaline, S4: supply to a glass melting furnace, and S5: : Dissolving and pyrolyzing an object to be treated suppresses the formation of metal oxides and reduces the amount of ruthenium (RuO ₄ ) volatilized in off-gas. S6: Hereafter, the melt is vitrified, and S
7: In the gas portion, the above-mentioned processing is performed as off gas.

[0031]

The method and apparatus for treating radioactive contaminants have the following effects. (1) Since radioactive contaminants are put into molten glass to dissolve the metal content in the molten glass, radioactive substances and solids contained in the radioactive contaminants are vitrified and stabilized. Can be locked into a state. (2) When the radioactive contaminant contains a glass material, a silica material, or the like, it can be melted or pyrolyzed by contact with molten glass, and it can be dealt with by vitrification. (3) When the radioactive contaminants contain volatile components, they can be treated with off-gas as a gas component, and a high volume reduction rate can be obtained in combination with the melting of solid components into the glass. (4) By pre-alkalizing radioactive contaminants, when ruthenium is contained, gasification due to the formation of oxides of ruthenium can be suppressed, and the confinement property in glass can be improved. it can. (5) In addition to being able to prevent the diffusion of radioactive substances during transportation by transporting radioactive contaminants in a closed container and dropping them into the glass melting tank by means of the connection port charging means, It is possible to reduce the volume of radioactive contaminants by an appropriate amount according to the operating state of the glass melting tank. (6) When the radioactive contaminants are granular, the hopper is attached to the closed container for transportation in a closed state, and the top and bottom of the closed container are turned upside down and attached to the glass melting tank so that the hopper and the connection port are connected. Thus, the radioactive contaminants can be flowed down into the glass melting tank for efficient treatment. (7) By feeding the radioactive pollutants into the glass melting tank by the air feeding means, the radioactive pollutants can be transferred while being isolated from the surroundings, and in addition, the gas fed by air can be treated as off-gas.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a first embodiment of an apparatus for treating radioactive contaminants according to the present invention.

FIG. 2 is a front sectional view of essential parts showing a second embodiment of the radioactive contaminant treatment apparatus according to the present invention.

FIG. 3 is a process explanatory view showing a processing example in the case where the radioactive contaminant to be processed by the apparatus of FIG. 2 is a granular body.

FIG. 4 is a front view showing blocks showing a third embodiment of the radioactive contaminant treatment apparatus according to the present invention.

FIG. 5 is a flowchart showing an example of a method for treating radioactive contaminants according to the present invention.

[Explanation of Codes] 1 Glass melting tank 6 Ceiling wall 7 Raw material supply port 8 Discharge port 9 Downflow nozzle 10 Input port 10a Open / close lid 11A, 11B Sealed container (element case) 12 Connection port 13 Input means 13a Shutter plate 13b Guide portion 13c Drive motor 13d Rack and pinion mechanism 14 Hopper 15 Opening / closing means 16 Silica gel adsorber (filter) 16a Lid 16b Container 16c Filter element 16d Fishing fitting 16e Mesh material 17 Air feeding means 18 Silica gel supply system 19 Mixing section 20 Storage hopper (sealed container) 21 Off-gas treatment system X Molten glass (melt) Y Radioactive contaminants

Claims (5)

[Claims] 1. A step of introducing a radioactive pollutant into a molten glass, a step of vitrifying the radioactive contaminant dissolved in the molten glass, and an off-gas treatment of a gasified component in the radioactive contaminant. The method for treating radioactive pollutants, comprising: 2. The method for treating radioactive contaminants according to claim 1, further comprising a step of alkalizing the radioactive contaminants in advance. 3. An airtight container for containing radioactive contaminants, a connection port arranged in the airtight container and connected to a glass melting tank,
An apparatus for treating radioactive contaminants, comprising: an input means arranged at the connection port for transferring the radioactive contaminants into the glass melting tank. 4. A closed container which contains granular radioactive contaminants and which is mounted upside down when the radioactive contaminants are transferred to the inside of a glass melting tank, and which is arranged at an upper opening of the sealed container. Radioactive contamination, comprising: a connection port for connecting to the connection port, a hopper arranged in the opposite direction to the connection port, and an opening / closing means arranged at the outlet of the hopper to allow passage of radioactive contaminants when opened. Object processing equipment. 5. The apparatus for treating radioactive contaminants according to claim 4, wherein the airtight means for transferring the granular radioactive contaminants to the glass melting tank is connected to the closed container.