CA3062368C - Method for processing radioactive waste cocktails - Google Patents
Method for processing radioactive waste cocktails Download PDFInfo
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- CA3062368C CA3062368C CA3062368A CA3062368A CA3062368C CA 3062368 C CA3062368 C CA 3062368C CA 3062368 A CA3062368 A CA 3062368A CA 3062368 A CA3062368 A CA 3062368A CA 3062368 C CA3062368 C CA 3062368C
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- cocktails
- tritiated water
- waste
- residual liquid
- radioactive
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- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000002901 radioactive waste Substances 0.000 title claims abstract description 15
- 238000012545 processing Methods 0.000 title claims abstract description 14
- XLYOFNOQVPJJNP-PWCQTSIFSA-N Tritiated water Chemical compound [3H]O[3H] XLYOFNOQVPJJNP-PWCQTSIFSA-N 0.000 claims abstract description 56
- 239000003960 organic solvent Substances 0.000 claims abstract description 56
- 239000002699 waste material Substances 0.000 claims abstract description 43
- 239000007788 liquid Substances 0.000 claims abstract description 34
- 238000009835 boiling Methods 0.000 claims abstract description 24
- 230000002285 radioactive effect Effects 0.000 claims abstract description 21
- 238000000926 separation method Methods 0.000 claims abstract description 21
- 239000004094 surface-active agent Substances 0.000 claims abstract description 16
- 230000005484 gravity Effects 0.000 claims abstract description 12
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- 238000001704 evaporation Methods 0.000 claims abstract description 9
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 8
- 238000005259 measurement Methods 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 239000012857 radioactive material Substances 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 15
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 6
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 239000007850 fluorescent dye Substances 0.000 description 5
- 239000010808 liquid waste Substances 0.000 description 5
- -1 aromatic carbon compound Chemical class 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 3
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 description 3
- IAUKWGFWINVWKS-UHFFFAOYSA-N 1,2-di(propan-2-yl)naphthalene Chemical compound C1=CC=CC2=C(C(C)C)C(C(C)C)=CC=C21 IAUKWGFWINVWKS-UHFFFAOYSA-N 0.000 description 2
- QKLPIYTUUFFRLV-YTEMWHBBSA-N 1,4-bis[(e)-2-(2-methylphenyl)ethenyl]benzene Chemical compound CC1=CC=CC=C1\C=C\C(C=C1)=CC=C1\C=C\C1=CC=CC=C1C QKLPIYTUUFFRLV-YTEMWHBBSA-N 0.000 description 2
- DYBIGIADVHIODH-UHFFFAOYSA-N 2-nonylphenol;oxirane Chemical compound C1CO1.CCCCCCCCCC1=CC=CC=C1O DYBIGIADVHIODH-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- XLYOFNOQVPJJNP-ZSJDYOACSA-N Heavy water Chemical compound [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 235000019329 dioctyl sodium sulphosuccinate Nutrition 0.000 description 2
- YHAIUSTWZPMYGG-UHFFFAOYSA-L disodium;2,2-dioctyl-3-sulfobutanedioate Chemical compound [Na+].[Na+].CCCCCCCCC(C([O-])=O)(C(C([O-])=O)S(O)(=O)=O)CCCCCCCC YHAIUSTWZPMYGG-UHFFFAOYSA-L 0.000 description 2
- 238000005567 liquid scintillation counting Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002123 temporal effect Effects 0.000 description 2
- LJKDOMVGKKPJBH-UHFFFAOYSA-L 2-ethylhexyl phosphate Chemical compound CCCCC(CC)COP([O-])([O-])=O LJKDOMVGKKPJBH-UHFFFAOYSA-L 0.000 description 1
- LJQGHMGOXZTLDS-UHFFFAOYSA-N C(C)(C)C1=C(C2=CC=CC=C2C=C1)C(C)C.N(CCO)CCO Chemical compound C(C)(C)C1=C(C2=CC=CC=C2C=C1)C(C)C.N(CCO)CCO LJQGHMGOXZTLDS-UHFFFAOYSA-N 0.000 description 1
- YZCKVEUIGOORGS-NJFSPNSNSA-N Tritium Chemical compound [3H] YZCKVEUIGOORGS-NJFSPNSNSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 150000001555 benzenes Chemical class 0.000 description 1
- 238000010549 co-Evaporation Methods 0.000 description 1
- 230000019771 cognition Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910052722 tritium Inorganic materials 0.000 description 1
- 210000002700 urine Anatomy 0.000 description 1
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/04—Treating liquids
- G21F9/06—Processing
- G21F9/08—Processing by evaporation; by distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/02—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/048—Purification of waste water by evaporation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/24—Treatment of water, waste water, or sewage by flotation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Measurement Of Radiation (AREA)
Abstract
A method for processing radioactive waste cocktails includes: evaporating tritiated water and a part of organic solvents, having boiling points no higher than the tritiated water, among components constituting the waste cocktails by heating the waste cocktails having been used for radioactive concentration measurement at step 1; facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the organic solvents in a separation tank at step 2; accommodating separately the tritiated water and the part of the organic solvents in first and second storage tanks, respectively, at step 3; and accommodating residual liquid consisting of the residual organic solvent, surfactant, and fluorescent agent, having boiling points higher than tritiated water in a third storage tank at step 4.
Description
METHOD FOR PROCESSING RADIOACTIVE WASTE COCKTAILS
BACKGROUND
Field The present disclosure relates to a method for processing radioactive waste cocktails and, more particularly, to a method for processing waste cocktails, which are generated after radioactive concentration measurement and have a risk of radioactive contamination.
Description of the Related Art Generally, a liquid scintillation counting method is widely used as a method for finding a radioactive concentration.
The liquid scintillation counting method is a method of determining the radioactivity concentration in a sample by measuring the scintillation generated by the interaction between beta (p) particles in the radioactive sample and a scintillator.
In the method, since radionuclides are all dissolved in fluorescent solution in a vial, the fluorescent solution acts as a detector. Accordingly, in whatever direction it is emitted, the p may be detected, thereby resulting in very high geometrical efficiency. Accordingly, a liquid scintillation counter (LSC) is generally used mainly for radioisotope handling agencies or nuclear power plants to measure 3-ray concentrations.
Therefore, waste cocktails are inevitably generated through operations of the LSC, and the waste cocktails consist of aromatic carbon compound which has a benzene nucleus. The generation of these waste cocktails occurs mainly in the measurement of low-concentration p-rays in urine samples, air samples, system water, and discharged liquid waste, which is performed when evaluating the presence of internal exposure by H-3 to workers in heavy water reactors.
Table 1 shows components and contents of the fluorescent solution as an example. Considering the domestic reality that nuclear power plants have been operating for about 30 years, it is estimated that a great amount of waste cocktails are being stored in waste storage warehouses. As shown in the table below, these waste cocktails are composed of highly volatile substances.
Therefore, when not properly managed, these waste cocktails may be a major cause of fire in the waste storage warehouses.
Nevertheless, a technology to deal with the waste cocktails has not been developed yet, requiring an urgent need for countermeasures.
BACKGROUND
Field The present disclosure relates to a method for processing radioactive waste cocktails and, more particularly, to a method for processing waste cocktails, which are generated after radioactive concentration measurement and have a risk of radioactive contamination.
Description of the Related Art Generally, a liquid scintillation counting method is widely used as a method for finding a radioactive concentration.
The liquid scintillation counting method is a method of determining the radioactivity concentration in a sample by measuring the scintillation generated by the interaction between beta (p) particles in the radioactive sample and a scintillator.
In the method, since radionuclides are all dissolved in fluorescent solution in a vial, the fluorescent solution acts as a detector. Accordingly, in whatever direction it is emitted, the p may be detected, thereby resulting in very high geometrical efficiency. Accordingly, a liquid scintillation counter (LSC) is generally used mainly for radioisotope handling agencies or nuclear power plants to measure 3-ray concentrations.
Therefore, waste cocktails are inevitably generated through operations of the LSC, and the waste cocktails consist of aromatic carbon compound which has a benzene nucleus. The generation of these waste cocktails occurs mainly in the measurement of low-concentration p-rays in urine samples, air samples, system water, and discharged liquid waste, which is performed when evaluating the presence of internal exposure by H-3 to workers in heavy water reactors.
Table 1 shows components and contents of the fluorescent solution as an example. Considering the domestic reality that nuclear power plants have been operating for about 30 years, it is estimated that a great amount of waste cocktails are being stored in waste storage warehouses. As shown in the table below, these waste cocktails are composed of highly volatile substances.
Therefore, when not properly managed, these waste cocktails may be a major cause of fire in the waste storage warehouses.
Nevertheless, a technology to deal with the waste cocktails has not been developed yet, requiring an urgent need for countermeasures.
2 [Table 1]
Component of fluorescent solution CAS No. Content (%) Triethyl phosphate 78-40-0 1 - 2.5 P-bis (o- methylstyryl)benzene 13280-61-0 1 - 2.5 Sodium dioctyl sulfosuccinate 577-11-7 1 - 2.5 Ethylene oxide-nonylphenol polymer 9016-45-9 10 - 20 2,5-Diaphenoloxazole 92-71-7 1 - 2.5 Diisopropylnaphthalene 38640-62-9 60 - 80 Phosphoric acid, 2-ethylhexyl ester, compound with 73070-48-1 10 - 20 2,2'-iminobis (Ethanol) Meanwhile, waste cocktails generated during operations of the LSC in domestic light water reactors have been reported to be contaminated with 1-1-3, and the radioactive concentration of H-3 contained therein was investigated at levels of 1,893.5 to 2,447.5 Bq/g.
Currently, for domestic nuclear power plants, the treatment technology for the waste cocktails generated during operations of the LSC has not been developed and the waste cocktails have been stored in the waste storage warehouses for a long time.
Therefore, a fire hazard is also high due to highly volatile alcohol contained in the waste cocktails.
Therefore, the development of stable technology is necessary to overcome temporal and spatial limitations for disposal of
Component of fluorescent solution CAS No. Content (%) Triethyl phosphate 78-40-0 1 - 2.5 P-bis (o- methylstyryl)benzene 13280-61-0 1 - 2.5 Sodium dioctyl sulfosuccinate 577-11-7 1 - 2.5 Ethylene oxide-nonylphenol polymer 9016-45-9 10 - 20 2,5-Diaphenoloxazole 92-71-7 1 - 2.5 Diisopropylnaphthalene 38640-62-9 60 - 80 Phosphoric acid, 2-ethylhexyl ester, compound with 73070-48-1 10 - 20 2,2'-iminobis (Ethanol) Meanwhile, waste cocktails generated during operations of the LSC in domestic light water reactors have been reported to be contaminated with 1-1-3, and the radioactive concentration of H-3 contained therein was investigated at levels of 1,893.5 to 2,447.5 Bq/g.
Currently, for domestic nuclear power plants, the treatment technology for the waste cocktails generated during operations of the LSC has not been developed and the waste cocktails have been stored in the waste storage warehouses for a long time.
Therefore, a fire hazard is also high due to highly volatile alcohol contained in the waste cocktails.
Therefore, the development of stable technology is necessary to overcome temporal and spatial limitations for disposal of
3 liquid wastes containing low and medium level beta-nuclides such as waste cocktails, to reduce the fire hazard, and to meet public sentiment in an environment that the domestic nuclear power plants are facing.
A perfect oxidation process through incineration may be the only way to apply to the treatment of waste cocktails generated during the operations of the LSC equipment, but incineration is likely to release radioactive contaminants into the atmosphere.
Therefore, incineration is difficult to apply to the treatment of waste cocktails due to unpreferable cognition of public and the potential to raise other environmental problems. At present, domestic nuclear power plants and radioisotope handling agencies are storing tens of tons of the LSC radioactive organic liquid wastes generated therefrom. In this regard, the Nuclear Safety and Security Commission (Korea) has warned of the fire hazard.
Therefore, there is an urgent need to secure safe disposal of the radioactive waste cocktails.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.
A perfect oxidation process through incineration may be the only way to apply to the treatment of waste cocktails generated during the operations of the LSC equipment, but incineration is likely to release radioactive contaminants into the atmosphere.
Therefore, incineration is difficult to apply to the treatment of waste cocktails due to unpreferable cognition of public and the potential to raise other environmental problems. At present, domestic nuclear power plants and radioisotope handling agencies are storing tens of tons of the LSC radioactive organic liquid wastes generated therefrom. In this regard, the Nuclear Safety and Security Commission (Korea) has warned of the fire hazard.
Therefore, there is an urgent need to secure safe disposal of the radioactive waste cocktails.
The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.
4 SUMMARY
Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art. With facts taken into consideration that the main components of waste cocktails consist of organic solvents, tritiated water, surfactants, and fluorescent agents, and boiling points and specific gravities of the components are different, the present disclosure is intended to propose a method for processing radioactive waste cocktails, wherein the method can safely separate the tritiated water contained in the waste cocktails.
In order to achieve the above objective according to one aspect of the present disclosure, there is provided a method for processing radioactive waste cocktails, the method comprising:
evaporating tritiated water and a part of organic solvent, having a boiling point no higher than the tritiated water, among components constituting waste cocktails by heating the waste cocktails having been used for radioactive concentration measurement, accommodated in a heating tank; facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the
Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art. With facts taken into consideration that the main components of waste cocktails consist of organic solvents, tritiated water, surfactants, and fluorescent agents, and boiling points and specific gravities of the components are different, the present disclosure is intended to propose a method for processing radioactive waste cocktails, wherein the method can safely separate the tritiated water contained in the waste cocktails.
In order to achieve the above objective according to one aspect of the present disclosure, there is provided a method for processing radioactive waste cocktails, the method comprising:
evaporating tritiated water and a part of organic solvent, having a boiling point no higher than the tritiated water, among components constituting waste cocktails by heating the waste cocktails having been used for radioactive concentration measurement, accommodated in a heating tank; facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the
5 organic solvent in a separation tank; accommodating separately the tritiated water and the part of the organic solvent, separated in the separation tank, in a first storage tank and in a second storage tank, respectively; and accommodating residual liquid consisting of residual organic solvent, surfactant, and fluorescent agent, having boiling points higher than the tritiated water, among the components constituting the waste cocktails at the evaporating the tritiated water and the part of the organic solvent in a third storage tank.
In addition, the separation tank may be provided with a transparent pipe for checking a water level, thereby checking a boundary point where the tritiated water and "some organic solvents" are separated into layers, and the transparent pipe for checking the water level may be provided with a buoy therein, the buoy having a specific gravity lighter than the tritiated water and heavier than the "some organic solvents".
In addition, the method may further comprises: separating particulate radioactive materials and non-radioactive solids contained in the residual liquid by feeding the residual liquid accommodated in the third storage tank to a filter unit; and, by measuring radioactivity of the residual liquid passed through the filter unit in a radioactivity meter, feeding the residual liquid
In addition, the separation tank may be provided with a transparent pipe for checking a water level, thereby checking a boundary point where the tritiated water and "some organic solvents" are separated into layers, and the transparent pipe for checking the water level may be provided with a buoy therein, the buoy having a specific gravity lighter than the tritiated water and heavier than the "some organic solvents".
In addition, the method may further comprises: separating particulate radioactive materials and non-radioactive solids contained in the residual liquid by feeding the residual liquid accommodated in the third storage tank to a filter unit; and, by measuring radioactivity of the residual liquid passed through the filter unit in a radioactivity meter, feeding the residual liquid
6 back to the filter unit when measured radioactivity thereof is above a reference value and discharging the residual liquid when the measured radioactivity thereof is below the reference value.
As described above, according to the method for processing the radioactive waste cocktails, the waste cocktails are separated into tritiated water containing H-3, which is a radioactive contaminant, and non-radioactive materials, whereby the tritium water is retrieved to the liquid waste treatment system of nuclear power plants, and non-radioactive materials can be disposed of as general wastes. As a result, the throughput of the radioactive wastes is reduced, thereby solving a problem of spatial limitations for the long-term storage of the radioactive wastes in a storage warehouse. Furthermore, it is effective in solving a fire hazard problem caused by highly volatile alcohol contained in the waste cocktails.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawing, in which:
As described above, according to the method for processing the radioactive waste cocktails, the waste cocktails are separated into tritiated water containing H-3, which is a radioactive contaminant, and non-radioactive materials, whereby the tritium water is retrieved to the liquid waste treatment system of nuclear power plants, and non-radioactive materials can be disposed of as general wastes. As a result, the throughput of the radioactive wastes is reduced, thereby solving a problem of spatial limitations for the long-term storage of the radioactive wastes in a storage warehouse. Furthermore, it is effective in solving a fire hazard problem caused by highly volatile alcohol contained in the waste cocktails.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawing, in which:
7 FIG. 1 is a schematic view showing a processing apparatus for explaining a method for processing radioactive waste cocktails according to the present disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
Hereinbelow, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
M FIG. 1 is a schematic view showing a processing apparatus for explaining a method for processing radioactive waste cocktails according to the present disclosure. As shown in the drawing, the method for processing radioactive waste cocktails of the present disclosure comprises: evaporating tritiated water and a part of organic solvent, which has a boiling point no higher than the tritiated water, among components constituting the waste cocktails by heating the waste cocktails, which have been used for radioactive concentration measurement, accommodated in a heating tank 10, by a heater 11 at step 1; facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the organic solvent in
DETAILED DESCRIPTION OF THE DISCLOSURE
Hereinbelow, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
M FIG. 1 is a schematic view showing a processing apparatus for explaining a method for processing radioactive waste cocktails according to the present disclosure. As shown in the drawing, the method for processing radioactive waste cocktails of the present disclosure comprises: evaporating tritiated water and a part of organic solvent, which has a boiling point no higher than the tritiated water, among components constituting the waste cocktails by heating the waste cocktails, which have been used for radioactive concentration measurement, accommodated in a heating tank 10, by a heater 11 at step 1; facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the organic solvent in
8 a separation tank 20 at step 2; accommodating separately the tritiated water and the part of the organic solvent, which are separated in the separation tank 20, in a first storage tank 30 and in a second storage tank 40, respectively, at step 3; and accommodating residual liquid consisting of the residual organic solvent, surfactant, and fluorescent agent, which have boiling points higher than tritiated water, among the components constituting the waste cocktails at step 1 in a third storage tank 50 at step 4.
First, in step 1, the components of the waste cocktails used for the radioactive concentration measurement are composed of tritiated water, organic solvents, surfactants, and fluorescent agents as shown in Table 2 below, and the boiling point of the tritiated water generally known is 100r.
In organic solvents, acetone, which has a boiling point of 56r, is an organic solvent having a boiling point lower than the tritiated water (hereinafter referred to as "some organic solvents" ); diisopropylnaphthalene and toluene, which are organic solvents, have boiling points of 251 C and 290 C, respectively, and are organic solvents having higher boiling points than tritiated water (hereinafter referred to as "residual organic solvents" ); surfactant generally has a high boiling point of 173
First, in step 1, the components of the waste cocktails used for the radioactive concentration measurement are composed of tritiated water, organic solvents, surfactants, and fluorescent agents as shown in Table 2 below, and the boiling point of the tritiated water generally known is 100r.
In organic solvents, acetone, which has a boiling point of 56r, is an organic solvent having a boiling point lower than the tritiated water (hereinafter referred to as "some organic solvents" ); diisopropylnaphthalene and toluene, which are organic solvents, have boiling points of 251 C and 290 C, respectively, and are organic solvents having higher boiling points than tritiated water (hereinafter referred to as "residual organic solvents" ); surfactant generally has a high boiling point of 173
9 to 215r; and fluorescent agent has a boiling point of 80 to 359 C. As described above, there are wide differences in boiling points depending on types of organic solvents.
[Table 2]
Component name Component Boiling point (melting point) Triethyl phosphate Surfactant 215 C
Sodium dioctyl sulfosuccinate Anionic 173 C
surfactant Ethylene oxide-nonylphenol Nonionic 200 C
polymer surfactant Phosphoric acid, 2-ethylhexyl Anionic ester, compound with surfactant 321 C
2,2'-iminobis (Ethanol) Diisopropylnaphthalene Organic solvent 290 C
Toluene Organic solvent 251 C
Acetone Organic solvent 56 C
P-bis (o- methylstyryl) Fluorescent 80 C
benzene agent 2,5-Diaphenoloxazole Fluorescent 359 C
agent Tritiated water 100 C
However, when tritiated water is combined with a fluorescent agent and an organic solvent, which are benzene-based, by surfactant, the tritiated water is evaporated at about 85 C by a co-evaporation effect, and "some organic solvents" (acetone) having a low boiling point are evaporated together therewith. In addition, benzene has a relatively low boiling point among fluorescent agents but may or may not evaporate at about 85 C depending on the component coupled therewith.
As such, when the tritiated water and the "some organic solvents" evaporate, the surfactant whose bonding force is weak is separated from the waste cocktails. Therefore, since there is no surfactant, the evaporated tritiated water is also separated from the evaporated benzene or organic solvent.
Therefore, when the waste cocktails are accommodated in the heating tank 10 and maintained at the temperature of 85 C by being heated, the tritiated water and "some organic solvents" or benzene, which have relatively low boiling points, among the components consisting the waste cocktails are evaporated and thus may be discharged from the heating tank 10. Meanwhile, "residual organic solvents", namely surfactants and fluorescent agents having a higher boiling point than 85 C, may remain in the heating tank 10.
At this time, the amount of residual liquid and the amount of evaporation, which remain after being heated in the waste cocktails supplied to the heating tank 10, are different depending on the amount of the organic solvent component, fluorescent solution, and the water, wherein the amount of residual liquid is about 60 to 90%, and the amount of evaporation is 10 to 40%. In addition, in the amount of evaporation, the tritiated water is 50 to 60%, and "some organic solvents" occupy the remaining 40 to 50%.
Subsequently, in step 2, the tritiated water and "some organic solvents" evaporated in a heating chamber are condensed passing through a condenser 23 and then stored in the separation tank 20. In the separation tank 20, the tritiated water in a liquid state and "some organic solvents" are separated. At this time, a specific gravity of the tritiated water is 1 g/cd and specific gravities of "some organic solvents" are 0.3 to 0.8 g/cd.
Because "some organic solvents" have specific gravities lower than the tritiated water, the tritiated water forms a lower layer in a separation chamber, and "some organic solvents" form an upper layer, thereby causing a layer separation in a vertical direction.
Subsequently, in step 3, the tritiated water formed in the lower layer by being separated in the separation tank 20 is separately accommodated in the first storage tank 30, and the "some organic solvents" foLmed in the upper layer by being separated in the separation tank 20 are separately accommodated in the second storage tank 40, thereby allowing the tritiated water and the "some organic solvents" to be separately stored.
At this time, the tritiated water in the lower layer and the "some organic solvents" in the upper layer should be discharged so as not to mix with each other when separately discharged. To this end, the separation tank 20 may be provided with a transparent pipe 21 for checking the water level, thereby checking the boundary point where the tritiated water and the "some organic solvents" are separated into layers. In addition, a buoy 22 which has a specific gravity lighter than the tritiated water and heavier than the "some organic solvents" is provided inside the transparent pipe 21 for checking the water level, wherein the buoy 22 is located at the boundary point where the tritiated water and the "some organic solvents" are separated into layers.
Accordingly, a manager may check the separation location of the layers, thereby controlling the amount of the tritiated water and the "some organic solvents", which are discharged. Further, a color of the buoy 22 is set to be clearly distinguishable from the colors of the tritiated water and the "some organic solvents" , whereby the manager may easily check the location of the buoy 22 with a naked eye.
Subsequently, in step 4, among the components constituting the waste cocktails in step 1, substances having higher boiling points than tritiated water, that is, the "residual organic solvents", the surfactants, and the fluorescent agents are not evaporated and remain as the residual liquid as they are in the liquid state. Then the residual liquid is accommodated in the third storage tank 50.
In addition, the present disclosure further comprises:
separating particulate radioactive materials and non-radioactive solids contained in the residual liquid by feeding the residual liquid accommodated in the third storage tank 50 to a filter unit 60 at step 5; and, by measuring radioactivity of the residual liquid passed through the filter unit 60 in a radioactivity meter 70, feeding the residual liquid back to the filter unit 60 when measured radioactivity thereof is above a reference value and discharging the residual liquid when the measured radioactivity thereof is below the reference value at step 6.
First, in step 5, the particulate radioactive materials contained in the residual liquid are Co-58, Co-60, Sr-90, and Cs-137, and the diameter thereof is approximately 0.3 gm.
Accordingly, radioactive particles or non-radioactive solids no less than 0.1 gm are removed from the residual liquid through the filter unit 60 and disposed of in accordance with the radioactive waste treatment standards.
Subsequently, in step 6, the residual liquid having passed through the filter unit 60 is passed through the radioactivity meter 70 to measure radioactivity thereof. At this time, a contamination reference value is set to 100 becquerel (Bq)/a, for example, and when the measured value is higher than the reference value, it is determined that the particulate radioactive material is not completely removed from the residual liquid. Accordingly, the residual liquid is transferred back to the filter unit 60 and then passed through the filter unit 60 again. In addition, when the measured radioactivity value is lower than 100 Bq/11-e, the residual liquid is determined to have no radioactive risk and may be treated as general waste.
As described above, the present disclosure separates safely the tritiated water from the waste cocktails by using the boiling point and the specific gravity of the components constituting the waste cocktails. Therefore, the present disclosure may solve a fire hazard by storing the tritiated water and the residual liquids in reservoirs at the nuclear power plant or the isotope-using institution, and the radioactive liquid. In addition, temporal and spatial limitations for radioactive liquid waste disposal may be overcome and a stable treatment technology that meets the public sentiment may be provided.
As used herein, the terms, "comprises" and "comprising" are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms, "comprises" and "comprising" and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components.
The embodiments described so far are merely illustrative of the exemplary embodiments of the present disclosure, and the scope of the present disclosure is not limited to the described embodiments. In addition, various changes, modifications, or substitutions may be made by those skilled in the art.
[Table 2]
Component name Component Boiling point (melting point) Triethyl phosphate Surfactant 215 C
Sodium dioctyl sulfosuccinate Anionic 173 C
surfactant Ethylene oxide-nonylphenol Nonionic 200 C
polymer surfactant Phosphoric acid, 2-ethylhexyl Anionic ester, compound with surfactant 321 C
2,2'-iminobis (Ethanol) Diisopropylnaphthalene Organic solvent 290 C
Toluene Organic solvent 251 C
Acetone Organic solvent 56 C
P-bis (o- methylstyryl) Fluorescent 80 C
benzene agent 2,5-Diaphenoloxazole Fluorescent 359 C
agent Tritiated water 100 C
However, when tritiated water is combined with a fluorescent agent and an organic solvent, which are benzene-based, by surfactant, the tritiated water is evaporated at about 85 C by a co-evaporation effect, and "some organic solvents" (acetone) having a low boiling point are evaporated together therewith. In addition, benzene has a relatively low boiling point among fluorescent agents but may or may not evaporate at about 85 C depending on the component coupled therewith.
As such, when the tritiated water and the "some organic solvents" evaporate, the surfactant whose bonding force is weak is separated from the waste cocktails. Therefore, since there is no surfactant, the evaporated tritiated water is also separated from the evaporated benzene or organic solvent.
Therefore, when the waste cocktails are accommodated in the heating tank 10 and maintained at the temperature of 85 C by being heated, the tritiated water and "some organic solvents" or benzene, which have relatively low boiling points, among the components consisting the waste cocktails are evaporated and thus may be discharged from the heating tank 10. Meanwhile, "residual organic solvents", namely surfactants and fluorescent agents having a higher boiling point than 85 C, may remain in the heating tank 10.
At this time, the amount of residual liquid and the amount of evaporation, which remain after being heated in the waste cocktails supplied to the heating tank 10, are different depending on the amount of the organic solvent component, fluorescent solution, and the water, wherein the amount of residual liquid is about 60 to 90%, and the amount of evaporation is 10 to 40%. In addition, in the amount of evaporation, the tritiated water is 50 to 60%, and "some organic solvents" occupy the remaining 40 to 50%.
Subsequently, in step 2, the tritiated water and "some organic solvents" evaporated in a heating chamber are condensed passing through a condenser 23 and then stored in the separation tank 20. In the separation tank 20, the tritiated water in a liquid state and "some organic solvents" are separated. At this time, a specific gravity of the tritiated water is 1 g/cd and specific gravities of "some organic solvents" are 0.3 to 0.8 g/cd.
Because "some organic solvents" have specific gravities lower than the tritiated water, the tritiated water forms a lower layer in a separation chamber, and "some organic solvents" form an upper layer, thereby causing a layer separation in a vertical direction.
Subsequently, in step 3, the tritiated water formed in the lower layer by being separated in the separation tank 20 is separately accommodated in the first storage tank 30, and the "some organic solvents" foLmed in the upper layer by being separated in the separation tank 20 are separately accommodated in the second storage tank 40, thereby allowing the tritiated water and the "some organic solvents" to be separately stored.
At this time, the tritiated water in the lower layer and the "some organic solvents" in the upper layer should be discharged so as not to mix with each other when separately discharged. To this end, the separation tank 20 may be provided with a transparent pipe 21 for checking the water level, thereby checking the boundary point where the tritiated water and the "some organic solvents" are separated into layers. In addition, a buoy 22 which has a specific gravity lighter than the tritiated water and heavier than the "some organic solvents" is provided inside the transparent pipe 21 for checking the water level, wherein the buoy 22 is located at the boundary point where the tritiated water and the "some organic solvents" are separated into layers.
Accordingly, a manager may check the separation location of the layers, thereby controlling the amount of the tritiated water and the "some organic solvents", which are discharged. Further, a color of the buoy 22 is set to be clearly distinguishable from the colors of the tritiated water and the "some organic solvents" , whereby the manager may easily check the location of the buoy 22 with a naked eye.
Subsequently, in step 4, among the components constituting the waste cocktails in step 1, substances having higher boiling points than tritiated water, that is, the "residual organic solvents", the surfactants, and the fluorescent agents are not evaporated and remain as the residual liquid as they are in the liquid state. Then the residual liquid is accommodated in the third storage tank 50.
In addition, the present disclosure further comprises:
separating particulate radioactive materials and non-radioactive solids contained in the residual liquid by feeding the residual liquid accommodated in the third storage tank 50 to a filter unit 60 at step 5; and, by measuring radioactivity of the residual liquid passed through the filter unit 60 in a radioactivity meter 70, feeding the residual liquid back to the filter unit 60 when measured radioactivity thereof is above a reference value and discharging the residual liquid when the measured radioactivity thereof is below the reference value at step 6.
First, in step 5, the particulate radioactive materials contained in the residual liquid are Co-58, Co-60, Sr-90, and Cs-137, and the diameter thereof is approximately 0.3 gm.
Accordingly, radioactive particles or non-radioactive solids no less than 0.1 gm are removed from the residual liquid through the filter unit 60 and disposed of in accordance with the radioactive waste treatment standards.
Subsequently, in step 6, the residual liquid having passed through the filter unit 60 is passed through the radioactivity meter 70 to measure radioactivity thereof. At this time, a contamination reference value is set to 100 becquerel (Bq)/a, for example, and when the measured value is higher than the reference value, it is determined that the particulate radioactive material is not completely removed from the residual liquid. Accordingly, the residual liquid is transferred back to the filter unit 60 and then passed through the filter unit 60 again. In addition, when the measured radioactivity value is lower than 100 Bq/11-e, the residual liquid is determined to have no radioactive risk and may be treated as general waste.
As described above, the present disclosure separates safely the tritiated water from the waste cocktails by using the boiling point and the specific gravity of the components constituting the waste cocktails. Therefore, the present disclosure may solve a fire hazard by storing the tritiated water and the residual liquids in reservoirs at the nuclear power plant or the isotope-using institution, and the radioactive liquid. In addition, temporal and spatial limitations for radioactive liquid waste disposal may be overcome and a stable treatment technology that meets the public sentiment may be provided.
As used herein, the terms, "comprises" and "comprising" are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms, "comprises" and "comprising" and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components.
The embodiments described so far are merely illustrative of the exemplary embodiments of the present disclosure, and the scope of the present disclosure is not limited to the described embodiments. In addition, various changes, modifications, or substitutions may be made by those skilled in the art.
Claims (3)
1. A method for processing radioactive waste cocktails, the method comprising:
evaporating tritiated water and a part of organic solvent, having a boiling point no higher than the tritiated water, among components constituting waste cocktails by heating the waste cocktails having been used for radioactive concentration measurement, accommodated in a heating tank;
facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the organic solvent in a separation tank;
accommodating separately the tritiated water and the part of the organic solvent, separated in the separation tank, in a first storage tank and in a second storage tank, respectively; and accommodating residual liquid consisting of residual organic solvent, surfactant, and fluorescent agent, having boiling points higher than the tritiated water, among the components constituting the waste cocktails at the evaporating the tritiated water and the part of the organic solvent in a third storage tank.
evaporating tritiated water and a part of organic solvent, having a boiling point no higher than the tritiated water, among components constituting waste cocktails by heating the waste cocktails having been used for radioactive concentration measurement, accommodated in a heating tank;
facilitating layer separation of two components to occur in a vertical direction by a difference in specific gravities of the two components by condensing the evaporated tritiated water and the part of the organic solvent in a separation tank;
accommodating separately the tritiated water and the part of the organic solvent, separated in the separation tank, in a first storage tank and in a second storage tank, respectively; and accommodating residual liquid consisting of residual organic solvent, surfactant, and fluorescent agent, having boiling points higher than the tritiated water, among the components constituting the waste cocktails at the evaporating the tritiated water and the part of the organic solvent in a third storage tank.
2. The method of claim 1, wherein the separation tank is provided with a transparent pipe for checking a water level, thereby checking a boundary point where the tritiated water and "some organic solvents" are separated into layers, and the transparent pipe for checking the water level is provided with a buoy therein, the buoy having a specific gravity lighter than the tritiated water and heavier than the "some organic solvents".
3. The method of claim 1, further comprising:
separating particulate radioactive materials and non-radioactive solids contained in the residual liquid by feeding the residual liquid accommodated in the third storage tank to a filter unit; and, by measuring radioactivity of the residual liquid passed through the filter unit in a radioactivity meter, feeding the residual liquid back to the filter unit when measured radioactivity thereof is above a reference value and discharging the residual liquid when the measured radioactivity thereof is below the reference value.
separating particulate radioactive materials and non-radioactive solids contained in the residual liquid by feeding the residual liquid accommodated in the third storage tank to a filter unit; and, by measuring radioactivity of the residual liquid passed through the filter unit in a radioactivity meter, feeding the residual liquid back to the filter unit when measured radioactivity thereof is above a reference value and discharging the residual liquid when the measured radioactivity thereof is below the reference value.
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