JPS58208700A - Method and device for processing radioactive liquid waste - 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] [Technical Field of the Invention] The present invention relates to a method and apparatus for treating radioactive waste liquid, and in particular to a method and apparatus for treating radioactive waste liquid, in particular a method for bringing radioactive substances attached to metal surfaces such as piping in an atomic couplant into contact with an electrolytic solution. As a result, the decontamination work that involves dissolving and removing the material will end! It concerns methods and equipment for processing radioactive decontamination waste fluid generated.

[Technical Background of the Invention II] Radioactive materials used in decontamination work to dissolve and remove radioactive materials attached to the fully curved surface of piping in nuclear facilities such as nuclear power plants by contacting them with an electrolyte. Generally, the electrolytic waste liquid is treated by neutralizing it and concentrating it from τ11.
``It was treated by concentrating it, separating it into water and a condensed waste liquid, and solidifying the concentrated waste liquid with cement or asphalt. When the above electrolytic waste liquid is neutralized using, for example, caustic soda, Na25O+ is generated according to the following reaction formula.

After the neutralization process, the reaction product is usually concentrated using an evaporative concentrator to separate the condensed water to be recovered or released into the environment and the IIIKB waste liquid containing the main part of the waste liquid. Na 2804 is contained in the concentrated waste liquid side. Other methods used for condensation in this field include reverse osmosis membrane method and electrodialysis method, but in either method, the concentrated waste liquid side contains Na25O*.

Therefore, decontamination waste liquid generated from decontamination work in which IJJ-emitting substances adhering to metal surfaces such as piping connected to an atomic h plant, etc. is dissolved and removed by contacting with an electrolyte, has a hII control level. In many cases, the waste liquid is in a relatively commercial condition, and if this waste liquid is treated with normal neutralization and concentration equipment, there is a high risk of exposure of workers due to increased radioactivity levels. [Purpose] The present invention has been made in order to eliminate the drawbacks of the conventional technology, and its purpose is to provide an improved radioactive waste liquid treatment technology, and particularly to reduce the risk of neutralization by 1 m. It is an object of the present invention to provide a processing method and apparatus for reducing removal lines.

[Summary of the Invention] The method for treating radioactive waste liquid of the present invention is a method for treating radioactive waste liquid that is produced by condensation during decontamination work, etc., in which radioactive substances attached to the metal surface of an atomic couplant, etc. are brought into contact with an electrolytic solution and removed by dissolution. Electricity W containing matter? Adding a chelating agent that forms a water-insoluble or slightly water-soluble chelate compound to the liquid waste liquid from C=-1! Then, the IC radioactive compound is extracted from the electrolytic waste solution into a solvent by the above treatment by intermittent or then mixed with an organic solvent, and then the radioactive compound is removed from the electrolytic waste solution. By separating 11 solvents and radioactive chelate/compound into 9 pieces while separating it into water and lll condensate liquid, it is made! ! The purpose of the present invention is to provide a treatment method and device that eliminates danger to personnel.

In the above-mentioned conventional neutralization and concentration method for concentrating radioactive decontamination waste liquid, it is relatively rare for one person to continue continuous work in practice, and the decondensed liquid at the unrestricted level is Bamboo is at risk of radiation exposure because it is processed in batches each time.
! However, according to the treatment method and apparatus of the present invention, by combining the treatment with a specific chelating agent and solvent extraction, the treatment operation can be carried out continuously and without fear of exposure to radiation. As the rooting agent, all chelating agents except polyaminocarboxylic acids such as EDTA, dicarboxylic acids such as citric acid, and condensed phosphates can be used. In particular, dimethylglyph I Ishim, oxine, dithizone, fluoro[]acetylatone (Ce H5,02SF3) [1' A△] and chelate resins, such as copolymers of chloromethylated styrene and divinylbenzene, are treated with T Cf. -1p'N
(CH2C00H) /W-introduced resin, 3-oxyphinylthiourea, (NH'2 C3NHC6H40
Condensate resins of H-3) and 71/-l, resins produced by co-condensation of gallic acid, resorcinol, and formaldehyde give good results. Polyaminocarboxylic acids such as EDTA, A-oxycarboxylic acids such as citric acid, and condensed phosphates are not preferred because they form a water-soluble chelate compound with the radioactive waste liquid. Trifluoroacetyl acetate gives particularly good results.

As the solvent in the present invention, any organic solvent that does not substantially dissolve in water can be used. Particularly preferred are organic solvents with a low boiling point, and among them, low-boiling halogenated hydrocarbon solvents such as trichlorotrifluorototane and dichlorodifluoroethane are particularly suitable.

[Embodiment 1 of the Invention An embodiment of the present invention will be explained in detail below with reference to the drawings.

The drawing shows the 98 method of removing radioactive substances according to the present invention.

1 is a schematic diagram illustrating an example of an apparatus.

The radioactive waste liquid 98311+ equipment shown in the drawing is a rigid electrolytic waste liquid storage 4! i1, an addition device for the organic solvent in which the chelating agent is dissolved (hereinafter referred to as the addition device) 2, and 1゛・liquid (
A radioactive substance chelate compound formation tank and solvent extraction tank (hereinafter referred to as extraction tank) 3, which connects a solvent phase) lead-out pipe 3a and a light liquid (aqueous phase) lead-out pipe 31) of electrolytic waste liquid, and a light liquid lead-out pipe 3
1) The receiver disposed at the other end is composed of an evaporation concentration device 5 connected via a tank 4 and a distillation device 6 connected to the other end of the φ liquid outlet pipe 3a. , the extraction tank 3 is connected to the rigid electrolytic waste liquid storage tank 1 and the addition device 2 by pipes 1a, 3c, and 2a, the tip of the pipe 3C is inserted into the bottom of the extraction tank 3, and the tip of the pipe 3C is expanded into a trumpet shape. The open end face (J multi-hole nozzle 3 (1) is fixedly installed. 7 is a pump.

The evaporator IIl condenser 5 consists of a heating unit 5a, an evaporator 5b, and a condenser 5C, and includes an upper pipe 5d and a pump 8.
A circulation path is formed by the ten-piece pipe 5e. The heating tank 5a is connected to the receiving tank 4 by a pipe 5':lf with a pump 9. A pipe 5q branches off from the pipe 5f, and the end of the pipe 59 opens into a receiving tank (not shown).

10.11 is an on-off valve. Condenser 5C is evaporator 5
It is connected to the upper part of the pipe 5h by a pipe 5h, and the condensed water generated here is discharged to the sample tank 12 by a pipe 5i=.

The distillation apparatus 6 is composed of a distiller 6a equipped with a heater 13 and a condenser/sparder 6C connected to the top of the distiller 6a by a pipe 6b. Condenser 6Cr: The condensed organic solvent is sent from piping 6d to a collection tank (not shown), while the raw sludge is discharged from piping 6e. 1
4.15 is an on-off valve.

In this device, for example, in the radioactive waste liquid storage tank 1, there are
The radioactive waste liquid 16 stored in the radioactive waste liquid storage tank 1 is stored at The pump 7 connects the pipes 1a and 3c to the extraction tank 3, and the porous nozzle 3d connects the pipes 1a and 3c to the extraction tank 3.
It is ejected from the bottom upwards. On the other hand, additive
The organic solvent 17 in which the chemical agent is dissolved is injected from the upper part of the extraction tank 3 through the pipe 2a, and
It is mixed with the internal C release resistant waste liquid using a stirring device W (not shown). In these mixed solutions, the radioactive substance reacts with the chelate, 1, and other agents to form a water-insoluble or 1-soluble chelate compound, and this chelate compound is dissolved in the chelate solvent. After the chelate compound is dissolved in the organic solvent, the mixture is allowed to stand and [! After being separated into ψ liquid and ψ liquid, the heavy liquid is polished to distillation unit 0, where it is distilled. When (-lichlorotrifluoro)thane is used as the organic solvent, its boiling point is low, only 47.6°C at 1 atm, and it easily separates into sludge and solvent vapor by distillation, and the sludge flows through pipe 6e. The vapor is condensed in the condenser 6C and then discharged from the pipe 6d to be reused.On the other hand, the light liquid passes through the light liquid outlet pipe 3b, and the light liquid is transferred to the tank/tank. l c = stored.

The liquid in the receiving tank 4 is sent to the evaporative concentrator 5 by the pump 9, where it is evaporated and concentrated and discharged into the sample tank 12. If the state of the light oil in the receiving tank 4 is such that it can be reused or released into the environment, the light liquid is recovered or released into the environment through the pipe 5g. Trichlorotrifluoroethane solvent has a density of 1,565! ] /'c i(
Since it is relatively large (25°C), separation from the aqueous phase due to the difference in specific gravity occurs relatively quickly, and its boiling point is low, so it can be distilled and produced at a lower temperature than water, making it unbeatable from an energy-saving perspective. It can be said that. In addition, TTA (1-lifluoroacetyl azetone) used as a chelating agent has a boiling point of 103 to 107°C, and even if the trichlorotrifluoroethane phase, which is a solvent, is distilled at 50°C, the solvent side remains It has the advantage that it remains in the water and can be reused repeatedly.

In this example, the electrolytic contaminated waste liquid was prepared in advance to form a compound with the radiation bamboo glume at a relatively low ρF1-Δ of the cleaning agent.
The need for H adjustment is relatively small. Note that the evaporative concentrator described in this embodiment is only an example of a concentrator, and it is of course possible to replace the evaporator section with an electric device.

(Effects of the invention) As is clear from the above explanation, according to the present invention, (7) M-emitting impurities (!111co, 60co) in decontamination waste liquid
etc. can be selectively removed and covered, and since the control level is reduced in the treatment after the removal of dead copper, it is possible to treat it with a simple waste treatment equipment, and it is possible to eliminate synthetic contaminants. It becomes concentrated and assimilated dust, and the effect of its production is young.

[Brief explanation of the drawing]

The drawings are schematic diagrams showing an embodiment of the tll@ waste liquid treatment method and apparatus of the present invention. 1... Radioactive electrolyte waste liquid storage tank 2...
・・・・・・・・・Ai solvent addition device 3...
......4 layers 1 to compound formation tank and solvent extraction tank J a...Liquid outlet pipe 3b...Light liquid outlet pipe 4・・・・・・・・・・・・Receiving tank 5・・・・・・・・・Evaporation concentrator F) a...
...Heating color 5tl... Evaporator 5C... Condenser 6... Distillation device 6a...・・・・・・・・・Distiller 6G・・・・・・・・・Condenser 16・・・・・・Radioactive waste liquid] 7・・・・・・・・・Organic solvent

Claims (1)

[Scope of Claims] (1) Decontamination by dissolving and removing radioactive substances on various waste liquids, including recycled waste liquid from desalination equipment, which is frequently generated in nuclear couplants, etc., or on metal surfaces. The electrolytic waste solution containing radioactive substances generated as a result of the work is treated by adding other agents to the radioactive substances and water-insoluble materials, which form a compound into the water-soluble ↓ray-1. and simultaneously or subsequently mixed with an organic solvent to extract the radioactive JIT 4.-u-ray 1 ~ compounds that have been absorbed by the treatment from the electrolytic waste solution into the organic solvent, and then the electrolytic waste solution from which radioactive chelate compounds have been removed. A method for treating radioactive waste liquid characterized by adding 1 l l l to water and IF degenerate waste liquid, while adding 1 l l l to the organic solvent and the radioactive chemical compound for 1 ll l l. The method for treating radioactive waste liquid according to claim 1, characterized in that the agent is added when forming a chelate compound and/or when concentrating the electrolytic waste liquid. (3) As the organic solvent, a low boiling point , and a method for treating radioactive fi waste liquid according to claim 1, which uses an organic solvent having a large difference in specific gravity from water. (4) Claim 1, which uses a halogenated hydrocarbon as the Pi-containing solvent. The method for treating radioactive waste liquid according to claim 3. (5) The method for treating radioactive waste liquid according to claim 4, using trichlorotrifluoroethane as the organic solvent. (6) The method for treating radioactive waste liquid according to claim 4. The method for treating a radioactive waste liquid according to claim 1, characterized in that the concentration is carried out by evaporative concentration. (7) The radioactive electrolyte waste liquid is concentrated by a reverse osmosis membrane or electrodialysis. 9. A method for treating radioactive waste liquid according to claim 1, which is a symptom of this. (8) A solution containing a radioactive chelate compound is distilled to produce a radioactive distillation residue and an unaccompanied 4-rating agent. A method for treating radioactive waste liquid according to claim 1, characterized in that the radioactive waste liquid is separated into a recovered solvent containing Next to the radioactive substance chelation content formation tank/solvent extraction, in which the chelating agent and organic solvent addition device are connected by an inlet pipe, the aqueous phase impulse pipe and organic solvent phase outgoing pipe are spaced apart below. Each end is connected, and the other end of the aqueous layer outlet pipe is connected to the lft of electrolytic ml solution.
1. A radioactive waste liquid processing apparatus, characterized in that the other end of the solvent extraction tank is connected to a distillation purification apparatus. (10) The radioactive waste liquid treatment apparatus according to claim 9, wherein the horizontal compression chamber is an evaporation concentration tank equipped with a heating can. (11) The radioactive waste liquid treatment device according to claim 9, wherein the gear device is a reverse osmosis concentration device. (12) The radioactive waste liquid treatment device according to claim 9, wherein the concentration device is an electrodialysis concentration device.