JPH0228119B2 - HOSHASEIHAIYOBAINOKOKASHORIHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for disposing of radioactive waste solvents. One of the important issues related to the use of nuclear power is the disposal of radioactive waste. For example, nuclear fuel reprocessing facilities, plutonium fuel processing facilities, and facilities that handle nuclear fuel and radioactive isotopes generate various radioactive solvents and waste liquids, such as tributyl phosphate.
Until now, there has been no established treatment method for these radioactive waste solvents, and in many cases they have been stored untreated within facilities, but this method of storing them in a liquid state does not allow them to be stored safely for long periods of time. That is difficult. For this reason, various methods for treating these radioactive waste solvents have been researched. Treatment methods have been proposed. However, the absorption treatment method requires a large amount of absorbent relative to the amount of radioactive waste solvent, resulting in an increase in waste volume, and has drawbacks such as leaching of the absorbed waste solvent at high temperatures. Furthermore, since the sintering method handles liquid materials, the equipment and operations are complicated, and there are also problems such as the need for treatment facilities for the waste gas generated during sintering. I couldn't say it was the right way to handle it. As a result of intensive research into a method for solidifying liquid radioactive waste solvent using simple equipment and operations, the inventors of the present invention have solved the shortcomings of these conventional techniques, and have found that it is possible to absorb a specific amount of epoxy resin and waste solvent. The inventors have discovered that a solidified product with excellent physical properties can be obtained by a simple operation of mixing a polymer and optionally an inorganic filler with a radioactive waste solvent and curing the mixture, leading to the present invention. That is, in the present invention, 15 to 300 parts by weight of the epoxy resin (B) is added to 100 parts by weight of the radioactive waste solvent (A).
2 or 2 polymers (C) that can absorb radioactive waste solvent
The present invention relates to a method for solidifying a radioactive waste solvent, which comprises mixing 200 parts by weight and an inorganic filler (D) in a ratio of 0 to 2000 parts by weight, and curing the mixture. The radioactive waste solvent treated in the present invention is:
For example, it refers to various radioactive waste solvents generated from various nuclear power-related facilities such as nuclear fuel reprocessing facilities and plutonium fuel processing facilities, and facilities that handle radioactive isotopes, or waste liquids containing these solvents as their main components. Types of radioactive waste solvents generated from nuclear power-related facilities and facilities that handle radioactive isotopes include, for example, phosphate esters such as monobutyl phosphate, dibutyl phosphate, tributyl phosphate, di-2-ethylhexyl phosphoric acid, and mono-2-ethylhexyl phosphoric acid; Aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as kerosene, hexane, decane, and dodecane, halogenated hydrocarbons such as trichlene and percrene, mineral oil, trilaurylamine, water, or mixtures of two or more of these. There is a lot of waste solvent. Further, the epoxy resin used as the solidifying resin in the present invention is a compound having two or more epoxy groups in one molecule. Specifically, such epoxy resins include glycidyl ether-based epoxy resins of polyphenol compounds such as bisphenol A, bisphenol F, and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane. ; Glycidyl ether type epoxy resin of nuclear hydride of the polyphenol compound; Glycidyl ether type epoxy resin of polyvalent phenols such as catechol, resorcinol, hydroquinone, phloroglucin; ethylene glycol, butanediol, glycerol, erythritol, polyoxyalkylene Glycidyl ether type epoxy resin of polyhydric alcohols such as glycol; Novolac type epoxy resin; Alicyclic type epoxy resin such as vinyl cyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide; Phthalic acid, cyclohexane-1,2 - Polyglycidyl ester type epoxy resins of ester condensates of polycarboxylic acids such as dicarboxylic acids; polyglycidylamine type epoxy resins; methyl epichloro type epoxy resins, and the like. Among these epoxy resins, polyphenols such as bisphenol A, bisphenol F, and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane are used from the viewpoint of reactivity when solidifying radioactive waste solvents. Particularly preferred are glycidyl ether-based epoxy resins, novolac-based epoxy resins, and polyglycidyl ether-based epoxy resins. Further, in the present invention, it is important that the amount of epoxy resin mixed with the radioactive waste solvent is 15 to 300 parts by weight per 100 parts by weight of the radioactive waste solvent. Mixed amount of epoxy resin is radioactive waste solvent 100%
If it is less than 15 parts by weight, not only will it not be possible to obtain a solidified material with practical strength, but the ability to trap radioactive substances will not be sufficient, and if it exceeds 300 parts by weight, volume reduction will be insufficient. , both are unfavorable. The amount of epoxy resin mixed in the present invention is preferably 25 to 200 parts by weight, particularly preferably 25 to 90 parts by weight, per 100 parts by weight of the radioactive waste solvent. Further, the polymer capable of absorbing radioactive waste solvent used in the present invention is a polymer having the property of partially or completely absorbing various solvents,
Specifically, polyolefins such as vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate copolymer, natural rubber, polypropylene, poly-4-methyl-1-pentene, Polymers of styrene derivatives such as tertiary-butylstyrene Styrene-butadiene copolymers; Rubbery ethylene-α-olefin copolymers such as ethylene-propylene copolymers and ethylene-1-butene copolymers; Rubbery ethylene-α -maleic anhydride modified product of olefin copolymer, chlorinated ethylene-α-olefin copolymer; ethylene-propylene-ethylidene norbornene copolymer, ethylene-propylene-
Dicyclopentadiene copolymer, ethylene-1-
Rubbery ethylene-α-olefin-diene copolymers such as butene-ethylidenenorbornene copolymers; maleic anhydride modified products of ethylene-α-olefin-diene copolymers, chlorinated ethylene-α-
Examples include olefin-diene copolymer, thiocol, and butadiene-based liquid rubber. Among these, particularly preferred polymers are vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, and ethylene-vinyl acetate copolymer. Furthermore, polymers capable of absorbing these radioactive waste solvents may be either solid or liquid, and in the case of solids, they may be in the form of powder, pellets, or fine particles from the viewpoint of operation and absorption speed when absorbing waste solvents. It is preferable to mix it in pieces. In the present invention, by mixing 2 parts by weight or more of the polymer to 100 parts by weight of the radioactive waste solvent, the mechanical strength of the resulting solidified product is further improved, and if it exceeds 200 parts by weight, the solubility reduction property is insufficient. Therefore, the amount of mixed polymer that can absorb radioactive waste solvent is
2 to 200 parts by weight, especially 10 to 100 parts by weight per 100 parts by weight are preferred. In addition, in the present invention, when solidifying radioactive waste solvent with epoxy resin, a specific amount of inorganic filler is further mixed in addition to the epoxy resin and cured, thereby increasing the mechanical strength of the solidified material and improving the confinement of radioactive substances. In the present invention, it is more preferable to mix an inorganic filler because the effect is further improved. Inorganic fillers used in the present invention include calcium carbonate, magnesium carbonate, silica, and silica.
Alumina, alumina, glass powder, glass beads, glass fiber, asbestos, mica, graphite, carbon fiber, titanium oxide, molybdenum disulfide, beryllium oxide, barium sulfate, magnesium oxide, calcium oxide, magnesium hydroxide, calcium hydroxide, Examples include clay and clay minerals such as talc, kaolin, acid clay, activated clay, atableite, grandite, generalite, bentonite, diatomaceous earth, montmorillonite, dolomite, waxite, vermiculite, activated carbon, metal powder, metal fiber, etc. . Among these, particularly preferred inorganic fillers are calcium carbonate, talc, dolomite, and bentonite. The blending amount of the inorganic filler is 2000 parts by weight or less per 100 parts by weight of the radioactive waste solvent. If the blending amount exceeds 2000 parts by weight, uniform mixing properties will be poor and volume reduction will be insufficient, which is not preferable. In the present invention, the blending amount of the inorganic filler is 20 to 400 parts by weight per 100 parts by weight of the radioactive waste solvent in terms of mixing workability with the waste solvent and epoxy resin and physical properties of the obtained solidified material, especially mechanical strength.
A range of parts by weight is particularly preferred. Further, in the present invention, these inorganic fillers may not only be non-radioactive but also radioactive themselves. In the present invention, to solidify the radioactive waste solvent,
First, the radioactive waste solvent mentioned above and the radioactive waste solvent 100
15 to 300 parts by weight, preferably
25 to 200 parts by weight of epoxy resin, 2 to 200 parts by weight
Stir in parts by weight, preferably 10 to 100 parts by weight of a polymer capable of absorbing radioactive waste solvent, and 0 to 2000 parts by weight, preferably 20 to 400 parts by weight of an inorganic filler, and further a curing agent for curing the epoxy resin. Mix uniformly using a mixer such as a mixer with blades or a static mixer. The amount of curing agent used is suitably 0.5 to 2 times the theoretical amount required to cure the epoxy resin. There is no particular restriction on the mixing order of each component, but in general, the radioactive waste solvent and epoxy resin are mixed first, and then a polymer curing agent that can absorb the radioactive waste solvent and, if necessary, an inorganic filler are added and mixed. is preferred. In the present invention, any compound known as a curing agent for epoxy resins can be used as the curing agent blended for curing the epoxy resin. Specifically, chain aliphatic polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylene diamine, and diethylaminopropylamine; cycloaliphatic polyamines; aliphatic polyamine adducts; ketoimines; modified aliphatic polyamines Polyamine; polyamide amine; aromatic amine; aromatic modified amine; aromatic modified polyamine; tertiary amine curing agent; mercaptan curing agent; acid anhydride curing agent; ethylene-maleic anhydride copolymer copolymers having acid anhydride groups such as; compounds having phenolic hydroxyl groups such as novolac type or resol type phenolic resin initial condensates;
Compounds such as dicyandiamide and melamine can be mentioned. Further, in the present invention, in addition to these components, compounding agents such as a curing accelerator may be added as necessary. Next, in order to solidify this mixture, the reaction rate between the epoxy resin and the curing agent is usually at least 65%, preferably at least 70%, to such an extent that the resulting solidified epoxy resin has sufficient strength. Let it harden until it becomes. Curing conditions are 5°C or higher, preferably 15°C to 80°C, for 5 minutes or more, usually 5 minutes to 80°C.
Just leave it for 10 hours. In the present invention, a radioactive waste solvent is blended with a polymer and an inorganic filler that can absorb a specific amount of radioactive waste solvent,
By solidifying this with a specific amount of epoxy resin, it has the advantage of converting radioactive waste solvent into a stable solid mass with excellent physical properties, particularly mechanical strength and the ability to trap radioactive substances. Furthermore, the present invention has the advantage that liquid radioactive waste solvent can be economically solidified using simple equipment and operations. Next, the present invention will be explained in more detail with reference to Examples. Example 1 As a simulated radioactive waste, 100 parts by weight of a mixture consisting of 86% by weight of tributyl phosphate, 9% by weight of n-dodecane, and 5% by weight of water and bisphenol A type epoxy resin (manufactured by Mitsui Petrochemical Epoxy Co., Ltd., product) were used. Epomic R-140, epoxy equivalent 185-195) 32 parts by weight and aliphatic polyamine curing agent ZS-2 (Fuji Kasei Co., Ltd.)
Co., Ltd., amine value 480) was uniformly mixed with a stirrer equipped with a stirring blade, and this was mixed with 43 parts by weight of talc and powdered vinyl chloride-vinyl acetate copolymer (Nippon Zeon Co., Ltd.). 43 parts by weight (manufactured by Zeon, trade name: 400 x 110A, average degree of polymerization 400) was added little by little while stirring, and after being left at room temperature for 15 hours, it was cured at 80°C for 3 hours. Table 1 shows the physical properties of the obtained solid mass. Example 2 Example 1 except that the amount of vinyl chloride-vinyl acetate copolymer was changed to 64 parts by weight.
A solid mass was obtained in the same manner as above. The physical properties of this solid mass are shown in Table 1. Example 3 In Example 1, powdered polyvinyl chloride (manufactured by Nippon Zeon Co., Ltd., trade name Zeon 43A, average degree of polymerization 1800) was used instead of the vinyl chloride-vinyl acetate copolymer.
A solid lump was obtained in the same manner as in Example 1 except that the weight parts were blended. Table 1 shows the physical properties of the obtained solid mass. Example 4 A solid lump was obtained in the same manner as in Example 1 except that 43 parts by weight of liquid polyvinyl acetate having an average degree of polymerization of 1500 was blended instead of the vinyl chloride-vinyl acetate copolymer. The physical properties of the obtained solid mass are
Shown in the table. Example 5 In Example 1, instead of the vinyl chloride-vinyl acetate copolymer, pelletized ethylene-vinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd., trade name: Evaflex-40, vinyl acetate content 40% by weight) was used. ) A solid lump was obtained in the same manner as in Example 1, except that 43 parts by weight was blended. Table 1 shows the physical properties of the obtained solid mass. 【table】

Claims (1)

[Claims] 1. For 100 parts by weight of radioactive waste solvent (A), 15 to 300 parts by weight of epoxy resin (B), 2 to 200 parts by weight of polymer (C) capable of absorbing radioactive waste solvent, and inorganic A method for solidifying a radioactive waste solvent, which comprises mixing a filler (D) in a proportion of 0 to 2000 parts by weight and curing the mixture. 2. The radioactive waste solvent contains at least one waste solvent selected from aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, mineral oil, phosphoric acid esters, trilaurylamine, and water, or these waste solvents as a main component. The method according to claim 1, wherein the waste liquid is a waste liquid. 3. The polymer according to claim 1 or 2, wherein the polymer capable of absorbing radioactive waste solvent is vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinyl acetate, or ethylene-vinyl acetate copolymer. Method. 4 Mixed amount of epoxy resin (B) is radioactive waste solvent (A)
4. The method according to claim 1, wherein the amount is 25 to 200 parts by weight per 100 parts by weight. 5 Mixed amount of inorganic filler (D) is 100% of radioactive waste solvent (A)
The method according to any one of claims 1 to 4, wherein the amount is 20 to 400 parts by weight. 6. The method according to any one of claims 1 to 5, wherein the inorganic filler (D) is radioactive. 7. The method according to any one of claims 1 to 6, wherein the inorganic filler (D) is calcium carbonate, talc, dolomite, or bentonite.