JP2015059870A - Radioactive waste liquid treatment method and radioactive waste liquid treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioactive waste liquid treatment method capable of adjusting a final pH of radioactive waste liquid to a neutral region (pH 4 to 9) while suppressing addition of treatment processes and increase of radioactive waste.SOLUTION: A filtration device 2 is connected to a colloid removal device 3. A most upstream adsorption tower 6 in an adsorption device 5 is connected to the colloid removal device 3. The colloid removal device 3 includes electrostatic filters 4. The adsorption towers 6 in the adsorption device 5 are sequentially connected. An adsorption tower 21 loaded with oxine-impregnated activated carbon is arranged downstream of the adsorption device 5. A discharge pipe 14 is connected to the adsorption tower 21. Not less than 1 μm of particles contained in radioactive waste liquid are filtered out by the filtration device 2 and negatively charged colloids are filtered out by the positively charged electrostatic filters 4. Radionuclides are removed by the adsorption device 5. Heavy metal ions contained in the radioactive waste liquid from the adsorption device 5 are removed by the adsorption tower 21. Furthermore, a pH of the radioactive waste liquid is adjusted to fall within a range of 4 to 9.

Description

  The present invention relates to a radioactive waste liquid treatment method and a radioactive waste liquid treatment apparatus, and more particularly to a radioactive waste liquid treatment method and a radioactive waste liquid treatment apparatus suitable for separating and removing a radionuclide from a radioactive waste liquid containing a radionuclide.

  As one of the processing methods for radioactive liquid waste containing radioactive nuclides generated in nuclear facilities, for example, nuclear power plants, there is an adsorption processing method for removing the radioactive nuclides from the radioactive liquid waste using an ion exchange resin or the like. This adsorption treatment method is a treatment method in which ionic radionuclides are adsorbed and removed by an inorganic or organic adsorbent or an ion exchange resin.

  Various properties (including components and pH) are assumed for the radioactive liquid waste generated in nuclear facilities. For example, acidic radioactive liquid waste and alkaline radioactive liquid waste are conceivable. In addition, depending on the adsorbent, there is an appropriate pH range for exerting the adsorption performance. When selecting such an adsorbent, the pH of the radioactive liquid waste is adjusted to acidic or alkaline according to the adsorbent, and then In some cases, the radionuclide contained in the radioactive liquid waste is adsorbed on the adsorbent. In any case, the radioactive liquid waste after the adsorption treatment is considered to have various pHs depending on the properties at the time of generation or the contained radionuclide and the selected adsorbent.

  The treatment of the radioactive liquid waste after the removal of the radionuclide has various options such as concentration reduction, storage, solidification, or release outside the system (for example, to the environment). In any case, these are carried out after adjusting the pH of the radioactive liquid waste to near neutrality. Therefore, when the pH of the radioactive liquid waste after the radionuclide adsorption treatment is out of the neutral region (for example, pH 4 to 9), a step of adjusting the pH of the radioactive liquid waste is necessary. If the radioactive liquid waste is acidic, it is necessary to carry out alkali addition or deoxidation treatment, and if the radioactive liquid waste is alkaline, it is necessary to neutralize it by adding an acid.

  An example of a treatment method for adsorbing and removing radionuclides from radioactive liquid waste is described in, for example, Ikeda et al., Proceedings of GLOBAL 2011, Dec.11-16, 2011, Makuhari, Japan, USA, Paper No. 524705 (2011). Has been. In this radionuclide adsorption / removal treatment method, radioactive waste liquid is passed through a container filled with an adsorbent, and ionic radionuclides contained in the radioactive waste liquid are adsorbed on the adsorbent and removed. In addition, before supplying a radioactive waste liquid in the container filled with the adsorbent, the particulate matter contained in the radioactive waste liquid is removed by a filtration device.

  In the radioactive waste liquid treatment method described in JP 2013-108808 A, the colloidal component contained in the radioactive waste liquid is removed by a filtration device (for example, an ultrafiltration membrane). The radioactive waste liquid is supplied to the filtration device after sodium hydroxide is added to the radioactive waste liquid and the pH of the radioactive waste liquid is adjusted to a predetermined value. The radioactive waste liquid from which the colloid has been removed by the filtration device is supplied to an adsorption tower packed with a titanate adsorbent. Since the titanate adsorbent easily adsorbs strontium, strontium contained in the radioactive waste liquid is removed in the adsorption tower.

JP 2013-108808 A

Ikeda et al., Proceedings of GLOBAL 2011, Dec.11-16, 2011, Makuhari, Japan, USA, Paper No. 524705 (2011)

  When chemicals such as acids and alkalis are added to the radioactive waste liquid after adsorption treatment and pH adjustment is performed, the process steps of the radioactive waste liquid increase accordingly, and the salt concentration in the radioactive waste liquid increases. There arises a problem that the amount of final radioactive waste generated increases.

  An object of the present invention is to provide a radioactive waste liquid treatment method and a radioactive waste liquid treatment apparatus capable of adjusting the final pH of a radioactive waste liquid to a neutral region (pH 4 to 9) while suppressing the addition of a treatment process and an increase in radioactive waste. It is to provide.

  A feature of the present invention that achieves the above object is that a colloidal substance, a particulate matter having a particle size larger than the colloidal substance, and a radioactive waste liquid containing the radioactive substance are supplied to the filtration device, and the particulate matter is filtered. The colloidal substance contained in the radioactive waste liquid discharged from the filtration device is removed, the radioactive waste liquid from which the colloidal substance has been removed is supplied to the first adsorption device, and the radionuclide contained in the radioactive waste liquid is first removed. The radioactive waste liquid removed by the adsorption device and discharged from the first adsorption device is supplied to the second adsorption device which is arranged downstream of the first adsorption device and is filled with an adsorbent carrying an oxine group on the surface. There is.

  The second adsorber, which is located downstream of the first adsorber and is filled with an adsorbent carrying an oxine group on the surface, rescues radioactive waste liquid discharged from the first adsorber, so the pH is adjusted. Without introducing the chemical to be added into the radioactive liquid waste, the pH of the radioactive liquid waste can be adjusted to a range of 4 to 9, and the amount of radioactive waste generated can be reduced.

  Preferably, at least one of an oxidizing agent, a pH adjusting agent and a reducing agent is injected into the radioactive liquid waste from which radionuclide ions have been removed by the first adsorption device, and the oxidizing agent, the pH adjusting agent and the reducing agent are injected. The radionuclide ions generated in the radioactive waste liquid by the injection of at least one of the above are removed by the adsorbent in the third adsorption device, and the radioactive waste liquid discharged from the third adsorption device is supplied to the second adsorption device. Is desirable.

  Accordingly, at least one of the oxidizing agent, the pH adjusting agent, and the reducing agent is injected into the radioactive waste liquid from which the ions have been removed by the first adsorption device, and at least one of the oxidizing agent, the pH adjusting agent, and the reducing agent. Since the radionuclide ions generated in the radioactive liquid waste by one injection are removed by the adsorbent in the second adsorption device, the removal efficiency of the radionuclide contained in the radioactive liquid waste can be further improved.

  According to the present invention, it is possible to adjust the pH of a radioactive waste liquid from a radioactive waste liquid to near neutrality with a simple apparatus configuration while reducing the amount of generated radioactive waste.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the radioactive waste liquid processing apparatus used for the processing method of the radioactive waste liquid of Example 1 which is one suitable Example of this invention. It is a block diagram of the radioactive waste liquid processing apparatus used for the processing method of the radioactive waste liquid of Example 2 which is another suitable Example of this invention. It is explanatory drawing which shows the removal rate for every chemical form of radioactive ruthenium contained in each radioactive waste liquid from which pH differs, and the chemical form of radioactive ruthenium.

  The inventors conducted a test to investigate the change in pH of the radioactive liquid waste accompanying the adsorption of the radionuclide in the course of developing a process for adsorbing various radionuclide ions. This is done with the assumption that depending on the combination of the adsorbents, the adsorption process of the radionuclide with one adsorbent in the previous stage may affect the adsorption performance of another radionuclide with another adsorbent in the subsequent stage. It was a test. As a result, regardless of whether the radioactive liquid waste is acidic or alkaline, the radioactive liquid waste is passed through a packed bed of oxine-impregnated activated carbon known to adsorb transition element ions so that the pH of the radioactive liquid waste is 4 to 4. Found to be adjusted within the range of 9.

  Based on the new findings obtained based on the above test results by the inventors, the inventors have adopted an adsorption device that adsorbs and removes radionuclides contained in radioactive waste liquid from an adsorption tower packed with activated carbon impregnated with oxine. It has been found that the pH of the radioactive liquid waste from which the radionuclide has been removed can be adjusted within the range of 4 to 9 by disposing it downstream of the radionuclide, leading to the creation of the present invention.

  The treatment of the radioactive waste liquid was assumed to treat a radioactive waste liquid containing a cation such as radioactive cesium or strontium, an anion such as radioactive antimony, and a transition metal ion such as radioactive cobalt. In order to selectively adsorb radioactive cesium and radioactive strontium, for example, natural zeolite, artificial zeolite or silicotitanate is used. In order to selectively adsorb radioactive antimony and the like, for example, using a cerium hydroxide-containing adsorbent, for selectively adsorbing radioactive heavy metals (for example, transition metal and rare earth ions), for example, oxine-impregnated activated carbon Is used.

  Table 1 shows adsorbents that can be used when the above radioactive ions are removed by adsorption, and the pH of each test water before and after passing through the packed bed of the adsorbent. Test water-1, test water-2 and test water-3 are all simulated water of radioactive liquid waste. Numerical values in parentheses () at the inlet indicate the respective pH values of test water-1, test water-2 and test water-3 at the inlet of the packed bed of the adsorbent. Each numerical value in () in each column of “Cs, Sr removal”, “anion removal” and “heavy metal removal” is a pH value after each test water passes through the adsorbent packed bed. In any case, the pH of each test water can be adjusted to a range of 4 to 9 by disposing the oxine-impregnated coal packed bed in the final stage of the radionuclide adsorption.

  Furthermore, the inventors examined the problems and countermeasures not only from the basic examination described above but also from the viewpoint of the equipment system. Simply by arranging the adsorption tower filled with activated carbon impregnated with oxine, the pH of the radioactive liquid waste became neutral in the adsorption tower, so that dissolved components contained in the radioactive liquid waste were deposited in the adsorption tower and blocked. There is concern about waking up. As a countermeasure, it is necessary to arrange a filtration device and a colloid removal device before the adsorption step so that the system configuration can reduce the solids precipitation potential as much as possible.

  Examples of the present invention reflecting the above examination results will be described below.

  A method for treating the radioactive liquid waste of Example 1, which is a preferred example of the present invention based on the above knowledge, will be described with reference to FIG. Furthermore, the radioactive waste liquid processing apparatus used for the processing method of this radioactive waste liquid is demonstrated using FIG.

  The radioactive liquid waste treatment apparatus 1 used in this embodiment includes a filtration device 2, a colloid removal device 3, an adsorption device (first adsorption device) 5, and an adsorption tower (second adsorption device) 21. The filtration device 2 is a device for physically filtering the particle components contained in the radioactive waste liquid, and has a cartridge filter (or pleat filter) filled with a filter material inside. The filtration device 2 removes particles of about 1 μm or more contained in the radioactive liquid waste. The colloid removing device 3 has a plurality of electrostatic filters 4 installed in the casing. The adsorption device 5 has a plurality of adsorption towers 6. Adsorbents selected according to the type of radionuclide contained in the radioactive liquid waste are packed in each adsorption tower 6 separately. A radioactive waste liquid supply pipe 7 is connected to the filtration device 2. The filtration device 2 and the colloid removal device 3 are connected by a connection pipe 8. Among the plurality of adsorption towers 6 in the adsorption apparatus 5, the adsorption tower 6 located on the most upstream side is connected to the colloid removing apparatus 3 by a connection pipe 9. Each adsorption tower 6 in the adsorption device 5 is sequentially connected by a pipe 10. An adsorption tower 21 disposed downstream of the adsorption device 5 and filled with activated carbon impregnated with oxine is connected to the adsorption tower 6 located most downstream in the adsorption device 5 by the pipe 11. Oxin-impregnated activated carbon is an adsorbent supported on the surface of activated carbon having an oxine group as a carrier.

  As an adsorbent to be packed in each adsorption tower 6 of the adsorption device 5, for example, natural zeolite, artificial zeolite and silicic titanic acid are selectively used to selectively adsorb radioactive cesium and radioactive strontium. In order to adsorb, for example, a hydrous cerium-containing adsorbent is used, and in order to selectively adsorb radioactive heavy metals, for example, oxine-impregnated activated carbon is used. These adsorbents are packed in each adsorption tower 6 separately. At least one of zeolite, ferrocyanide, titanate compound, titanate compound, ion exchange resin, chelate resin, activated carbon and impregnated activated carbon is selected as the adsorbent for adsorbing the radionuclide used in the adsorption device 5. . Here, in the present embodiment, as described above, the adsorption tower 21 filled with oxine-impregnated activated carbon is disposed downstream of the adsorption device 5.

  The processing method of the radioactive waste liquid of a present Example using the radioactive waste liquid processing apparatus 1 is demonstrated.

  Particles of 1 μm or more contained in the radioactive liquid waste are removed by the cartridge filter in the filtration device 2. The radioactive waste liquid discharged from the filtration device 2 is supplied to the colloid removal device 3 through the connection pipe 8.

  The colloid contained in the radioactive liquid waste is removed by the electrostatic filter 4 in the colloid removing device 3. Fine particles of less than 1 μm are called colloids. The colloid contains a radionuclide (such as radiocesium, radiostrontium and radioantimony), and the removal of the colloid by the electrostatic filter 4 also removes the radionuclide contained in the colloid. The surface of the colloid is positively or negatively charged. Whether the colloid is positively or negatively charged depends on the material forming the colloid and the surface structure. For example, colloids derived from soil components are often negatively charged. In the present embodiment, a positively charged electrostatic filter 4 in the colloid removing device 3 is used, and the negatively charged colloid contained in the radioactive waste liquid is attached to the surface of the electrostatic filter 4 and removed. Is done. It is not necessary to adjust the pH of the radioactive liquid waste supplied to the colloid removing device 3. In the electrostatic filter 4, colloidal particles having a particle size in the range of about 1 nm or more and less than 1 μm are removed.

  The radioactive liquid waste from which the colloidal particles have been removed is supplied to the adsorption tower 6 of the adsorption device 5 through the connection pipe 9. The radioactive liquid waste supplied to the adsorption device 5 does not contain particle components and colloids. For example, radioactive nuclides such as radioactive cesium, radioactive strontium and radioactive antimony contained in the radioactive liquid waste are ions. Each time the radioactive liquid waste passes through the plurality of adsorption towers 6, each radionuclide such as radioactive cesium, radioactive strontium, and radioactive iodine contained in the radioactive liquid waste is separately adsorbed and removed by the adsorbent in each adsorption tower 6.

  Transition metal ions such as cobalt remaining in the radioactive waste liquid discharged from the adsorbing device 5 and rare earth metal element ions such as balustrade and cesium are adsorbed and removed by the oxine-impregnated activated carbon in the adsorption tower 21. In the adsorption tower 21, the pH of the radioactive liquid waste is adjusted to neutral (pH 4 to 9). The pH of the treated water discharged from the adsorption tower 21 to the discharge pipe 14 is adjusted to (range 4 to 9). Each adsorption tower 6 of the adsorption device 5 is filled with a corresponding adsorbent in an amount capable of sufficiently adsorbing the total amount of each radionuclide contained in the radioactive liquid waste. For this reason, the density | concentration of each radionuclide contained in the treated water discharged | emitted from the adsorption tower 21 to the discharge pipe 14 becomes below a measurement lower limit. The treated water discharged from the adsorption device 5 is supplied to and stored in a storage tank (not shown) through the discharge pipe 14.

  According to the present embodiment, the amount of radioactive waste generated can be reduced with a simple device configuration including the filtration device 2, the colloid removal device 3 using the electrostatic filter 4, and the adsorption device 5. It can be removed up to the lower limit of measurement. Furthermore, by arranging the adsorption tower 21 filled with oxine-impregnated activated carbon downstream of the adsorption device 5, the pH of the radioactive liquid waste is adjusted to 4 to 9 without introducing the chemical for adjusting the pH into the radioactive liquid waste. Can be adjusted to the range.

  For the removal of the radionuclide from the radioactive liquid waste using the adsorbent, a cation exchange resin, a chelate resin, an anion exchange resin, or the like is used. These adsorbents have a high removal performance for ions having a positive charge, ions having a negative charge, and ions forming a complex. However, the adsorbent has relatively low removal performance for colloids and neutral dissolved species.

  For this reason, in order to efficiently remove the radionuclide contained in the radioactive liquid waste, it is desirable to adjust the chemical form of the radionuclide contained in the radioactive liquid waste using an oxidizing agent, a reducing agent or a pH adjuster. However, in reality, many radionuclides take multiple chemical forms, so even if the state of the radioactive liquid waste (such as pH) is adjusted to a certain condition, all the radionuclides contained in the radioactive liquid are completely removed. It is difficult to do.

  Therefore, the inventors diligently studied a method capable of efficiently removing the radionuclide from the radioactive liquid waste using the adsorbent even when the type and concentration of the radionuclide and the composition of the radioactive liquid waste are unknown. As a result of this examination, the radionuclide contained in the radioactive liquid waste is passed through the adsorbent layer and removed by the adsorbent in the adsorbent layer, and then, at least one of the oxidizing agent, the reducing agent, and the pH adjusting agent. It is effective to remove the radioactive nuclides contained in the radioactive waste liquid by adding the chemical to the radioactive waste liquid and passing the radioactive waste liquid containing the chemical through the adsorbent layer again to remove the radionuclide contained in the radioactive waste liquid. The inventors have further found that this is a method for removing nuclides.

  An explanation will be given by taking ruthenium, which is one of radionuclides, as an example. It is known that a ruthenium radioisotope, for example, Ru-106, takes a plurality of oxidation numbers and takes a plurality of chemical forms depending on the properties of the radioactive liquid waste.

  The inventors changed the pH of seawater containing ruthenium to acidic (pH 2), neutral (pH 7), and alkaline (pH 12), and the removal rate by the adsorbent of each ruthenium having different chemical forms contained in sea water at each pH. Asked. As a result, the typical chemical forms of ruthenium contained in the seawater of each pH described above and the removal rate of the ruthenium of each chemical form contained in the seawater of each pH by the adsorbent are shown in FIG.

In neutral seawater, ruthenium exists mainly as cations (Ru (OH) ₂ ^{+ and the} like) and neutral dissolved species (Ru (OH) _{4 and the} like) and is difficult to remove due to the adsorbent. The proportion of dissolved species is about 74%. On the other hand, in acidic (pH 2) seawater, about 58% of ruthenium is present as a cation (such as RuCl ₂ ⁺ ) and about 12% as an anion (such as RuCl ₄ ⁻ ). ₃ ) is about 30%. In alkaline seawater, almost 100% are ruthenium neutral dissolved species (Ru (OH) ₄ ).

  Therefore, in order to remove ruthenium contained in the radioactive liquid waste with the adsorbent, it is desirable to remove the ruthenium by adsorbing with the adsorbent after adjusting the radioactive liquid waste to be acidic. In this case, about 30% of the neutral dissolved species contained in the acidic radioactive liquid waste cannot be removed by the adsorbent.

Therefore, for example, when ruthenium adsorption treatment is first performed with an adsorbent on a neutral radioactive liquid waste, 26% of ruthenium cations (Ru (OH) ₂ ⁺ ) are removed. After that, when the radioactive liquid waste is adjusted to acidic (for example, pH 2) and the ruthenium is adsorbed, the ratio of neutral dissolved species remaining in the radioactive liquid waste is reduced to about 22% (= 74% × 30%). be able to. Therefore, before adjusting the pH of the radioactive liquid waste, the ruthenium that can be removed from the radioactive liquid waste is adsorbed and removed, and then the pH of the radioactive liquid waste is adjusted to acidic (for example, pH 2) and the ruthenium adsorption process is performed again. Thus, it is possible to reduce neutral dissolved species that are difficult to remove with an adsorbent contained in the radioactive liquid waste.

  For example, when the pH of the radioactive liquid waste is 2, when the adsorption treatment of ruthenium contained in the radioactive liquid waste is performed, about 30% of the neutral dissolved species remains in the radioactive liquid waste. When the pH of the radioactive liquid waste is adjusted to pH 2 again and the adsorption treatment with the adsorbent is performed, the ratio of the neutral dissolved species remaining in the radioactive liquid waste is 9% (= 30% × 30%). Reduced.

  As described above, according to the method for treating a radioactive waste liquid newly created by the inventors, the radionuclide contained in the radioactive waste liquid can be efficiently removed by the adsorbent.

  Examples of the adsorbent include at least one of ion exchange resin (cation exchange resin, anion exchange resin), chelate resin, activated carbon, oxine-impregnated activated carbon, zeolite, titanate compound, titanate compound, and ferrocyanide. Used. These adsorbents are appropriately selected and used according to the type of radionuclide to be adsorbed. Examples of usable oxidizing agents include aqueous solutions of hydrogen peroxide, ozone, permanganic acid and salts thereof, and aqueous solutions of hypochlorous acid and salts thereof.

  Examples of the reducing agent that can be used include ascorbic acid, hydrazine, and oxalic acid. Examples of the pH adjuster include acid solutions such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid, and alkaline solutions such as sodium hydrogen carbonate, sodium carbonate, sodium hydroxide, and potassium hydroxide.

  The method for treating the radioactive liquid waste of Example 2, which is another preferred example of the present invention, reflecting the above-mentioned new knowledge obtained by the inventors in the above-mentioned Example 1, will be described with reference to FIG. To do.

  The radioactive waste liquid treatment apparatus 1B used in the radioactive waste liquid treatment method of the present embodiment is the same as the adjustment tank (liquidity adjustment unit) 4 and pH adjuster in the radioactive waste liquid treatment apparatus 1 used in the radioactive waste liquid treatment method of Example 1. It has the structure which added the supply apparatus and the adsorption | suction apparatus 5B. Other configurations of the radioactive liquid waste treatment apparatus 1B are the same as those of the radioactive liquid waste treatment apparatus 1.

  The structure different from the radioactive waste liquid processing apparatus 1 of the radioactive waste liquid processing apparatus 1B is demonstrated. The adjustment tank 15 is connected to the adsorption tower 2 </ b> A located most downstream in the adsorption device 2 by the pipe 12. The pH adjusting agent supply device has a pH adjusting agent tank 16 and a pH adjusting agent supply pipe 17, and the pH adjusting agent tank 16 is connected to the adjustment tank 15 by a pH adjusting agent supply pipe 17 provided with an on-off valve (not shown). Is done. In this embodiment, the pH adjusting agent tank 16 is filled with a hydrochloric acid aqueous solution that is a pH adjusting agent.

  The adsorption device 5B has a plurality of adsorption towers 6B. The adsorbent selected according to the type of radionuclide contained in the radioactive liquid waste is separately packed in each adsorption tower 6B. The pipe 13 connected to the adjustment tank 15 is connected to the adsorption tower 6B located most upstream in the adsorption device 5B. Each adsorption tower 6B in the adsorption device 5B is sequentially connected by a pipe 10B.

  The adsorption tower 21 filled with oxine-impregnated activated carbon is disposed downstream of the adsorption device 5B, and is connected to the adsorption tower 6B located most downstream in the adsorption device 5B by the pipe 11. A discharge pipe 14 is connected to the adsorption tower 21.

  Each adsorbent layer in each adsorption tower 6B is separately filled with an adsorbent selected according to the radionuclide to be removed by adsorption. In order to selectively adsorb radioactive cesium and radioactive strontium, for example, natural zeolite, artificial zeolite and silicic titanic acid are used, and in order to selectively adsorb radioactive antimony and the like, for example, a hydrous cerium-containing adsorbent is used. Use. In addition, an adsorbent layer of a certain adsorption tower 2A is filled with ion exchange resins (cation exchange resin and anion exchange resin).

  The processing method of the radioactive waste liquid of a present Example using the radioactive waste liquid processing apparatus 1B is demonstrated. In the method for treating the radioactive liquid waste of the present embodiment, the radioactive liquid waste generated in the boiling water nuclear power plant is processed. The radioactive liquid waste includes, for example, transition metals such as ruthenium, technetium and niobium, alkali metals such as cesium, alkaline earth metals such as strontium, rare earth elements such as cerium, halogens such as antimony, tellurium and iodine, and carbon, Contains one or more radionuclide of non-metallic elements such as boron.

  The radioactive liquid waste containing a plurality of radionuclides is sequentially supplied to the filtration device 2 and the colloid removal device 3 as in the first embodiment. Particles of 1 μm or more contained in the radioactive liquid waste are removed by the filtration device 2. Then, when the radioactive waste liquid discharged | emitted from the filtration apparatus 2 flows in each adsorption tower 6 of the adsorption apparatus 5, the adsorbent in each adsorption tower 6 is the radioactive according to the kind of adsorbent in an adsorbent layer. It adsorbs and removes cations and anions of radionuclides such as ruthenium contained in the waste liquid. The radionuclide that has not been adsorbed and removed by the adsorbent in each adsorption tower 6 flows through the pipe 12 together with the radioactive waste liquid and is guided to the adjustment tank 15.

When the pH of the radioactive liquid waste supplied to the adsorption device 5 is 7, ruthenium, which is a kind of radionuclide, is a cation (such as Ru (OH) ₂ ⁺ ) and neutral dissolved species (Ru) in the radioactive liquid waste. (OH) ₄ etc.). Ruthenium cations (Ru (OH) ₂ ^{+ and the} like) are adsorbed and removed in the corresponding adsorption tower 6 while the radioactive liquid waste flows through the adsorption device 5. Ruthenium neutral dissolved species (such as Ru (OH) ₄ ) flow into the adjustment tank 15 without being removed by the adsorption device 5.

The aqueous hydrochloric acid solution in the pH adjusting agent tank 16 is injected into the radioactive waste liquid in the adjusting tank 15 through the pH adjusting agent supply pipe 17. The radioactive waste liquid in which ozone is dissolved and the hydrochloric acid aqueous solution are mixed in the adjustment tank 15 by the stirring device. Ruthenium neutral dissolved species (Ru (OH) ₄ ), which was not converted to ruthenium cations by ozone gas injection, adjusts the radioactive liquid waste to acidic (for example, pH 2) by injection of hydrochloric acid aqueous solution. To cations (such as RuCl ₂ ⁺ ), ruthenium anions (such as RuCl ₄ ⁻ ), and neutral dissolved species of ruthenium (such as RuCl ₃ ). Radionuclides other than ruthenium contained in the radioactive liquid waste are also converted into cations and anions.

Ruthenium cations (such as RuCl ₂ ⁺ ), ruthenium anions (such as RuCl ₄ ⁻ ) and neutral dissolved species of ruthenium (such as RuCl ₃ ) generated in the adjustment tank 15, and radionuclides other than ruthenium A radioactive liquid waste containing cations, anions and neutral dissolved species is supplied through the pipe 13 to the adsorption tower 6B located at the uppermost stream of the adsorption device 5B. And this radioactive waste liquid is sequentially supplied to each other adsorption tower 6B of the adsorption device through the pipe 12. Trivalent ruthenium cations (such as RuCl ₂ ⁺ ), ruthenium anions (such as RuCl ₄ ⁻ ), and radionuclide cations and anions other than ruthenium are adsorbed by the adsorbent in the corresponding adsorption tower 6B. Removed. Radioactive waste liquid containing neutral dissolved species of ruthenium (such as RuCl ₃ ) and radionuclides other than ruthenium that have not been removed by each adsorption tower 6B of the adsorption device 5B is discharged from the adsorption device 5B to the exhaust pipe 14.

  The aqueous pH adjuster solution may or may not be added to the radioactive waste liquid in the adjustment tank 15 as necessary.

  In the present embodiment, an example in which a pH adjuster is added to the radioactive liquid waste has been described. However, as the chemical agent to be added to the radioactive liquid waste, at least one of an oxidizing agent, a reducing agent, and a pH adjuster may be used. For example, when an oxidizing agent and a reducing agent are further added to the radioactive liquid waste in the adjustment tank 15, an oxidizing agent supply having an oxidizing agent tank and an oxidizing agent supply pipe provided with an on-off valve is provided in the same manner as the pH adjusting agent. What is necessary is just to connect the reducing agent supply apparatus which has a reducing agent supply piping which provided the apparatus, the reducing agent tank, and the on-off valve to the adjustment tank 15, respectively.

  In the present embodiment, the effects produced in the first embodiment can be obtained. Furthermore, in the present embodiment, ions (cations and anions) of the radionuclide such as ruthenium contained in the radioactive waste liquid are removed by the adsorption device 5, and the neutral dissolved species of the radionuclide such as ruthenium are contained in the adjustment tank 15. Injecting hydrochloric acid, which is a pH adjuster, into the radioactive liquid waste containing the radioactive nuclides such as ruthenium, and adjusting the pH of the radioactive liquid waste to, for example, the acidity of the radioactive nuclides such as ruthenium. Sex dissolved species can be converted into cations and anions. For this reason, cations and anions of radionuclides such as ruthenium generated from neutral dissolved species can be removed by adsorption with the adsorption device 5B. For this reason, the radionuclide contained in the radioactive liquid waste can be further reduced. In this embodiment, the removal efficiency of the radionuclide contained in the radioactive liquid waste can be further improved.

  DESCRIPTION OF SYMBOLS 1, 1B ... Radioactive waste liquid processing apparatus, 2 ... Filtration apparatus, 3 ... Colloid removal apparatus, 4 ... Electrostatic filter, 5, 5B ... Adsorption apparatus, 6, 6B, 21 ... Adsorption tower, 15 ... Adjustment tank, 16 ... pH Adjustment agent tank, 17 ... pH adjustment agent supply piping.

Claims (8)

  A colloidal material, a radioactive waste liquid containing a particulate material having a particle size larger than that of the colloidal material and a radioactive material is supplied to a filtration device, the particulate material is removed by the filtration device, and discharged from the filtration device. The colloidal substance contained in the radioactive liquid waste is removed, the radioactive liquid waste from which the colloidal substance has been removed is supplied to the first adsorption device, and the radionuclide contained in the radioactive liquid waste is removed by the first adsorption device. The radioactive waste liquid removed and discharged from the first adsorbing device is supplied to a second adsorbing device which is disposed downstream of the first adsorbing device and is filled with an adsorbent carrying an oxine group on its surface. A method for treating radioactive liquid waste.   The method for treating radioactive liquid waste according to claim 1, wherein the colloidal substance is removed by an electrostatic filter.   The method for treating a radioactive liquid waste according to claim 2, wherein the removal of the negatively charged colloidal substance is performed using the electrostatic filter that is positively charged.   At least one of an oxidizing agent, a pH adjusting agent and a reducing agent is injected into the radioactive liquid waste from which the radionuclide ions have been removed by the first adsorption device, and the oxidizing agent, the pH adjusting agent and the reducing agent are injected. The radionuclide ions generated in the radioactive liquid waste by injection of at least one of the agents are removed by the adsorbent in the third adsorption device, and the radioactive liquid waste discharged from the third adsorption device is removed. The processing method of the radioactive liquid waste of Claim 1 supplied to a 2nd adsorption | suction apparatus.   The radioactive waste liquid discharged from the first adsorption device is supplied to a liquidity adjusting unit, and injection into at least one of the oxidizing agent, the pH adjusting agent, and the reducing agent into the radioactive waste liquid is performed as the liquidity. The processing method of the radioactive liquid waste of Claim 4 performed in an adjustment part.   A filtration device that removes particulate matter having a particle size larger than the colloidal material from the radioactive liquid waste, a colloid removal device that is connected to the filtration device and removes the colloidal material, and is connected to the colloid removal device and is radioactive. A first adsorbing device having an adsorbent for adsorbing nuclides, and a second adsorbing material arranged downstream of the first adsorbing device and connected to the first adsorbing device and carrying an oxine group on the surface thereof. A radioactive waste liquid treatment device comprising an adsorption device.   The radioactive waste liquid processing apparatus according to claim 6, wherein the colloid removing apparatus has an electrostatic filter for removing the colloidal substance. An injection device for injecting at least one of an oxidizing agent, a pH adjusting agent, and a reducing agent into the radioactive liquid waste that has been removed from the first adsorption device after removal of the radionuclide, the oxidizing agent, and the pH adjustment A third adsorption device for removing ions of the radionuclide generated in the radioactive liquid waste by injection of at least one of an agent and the reducing agent;
The radioactive waste liquid treatment apparatus according to claim 6, wherein the second adsorption device is disposed downstream of the third adsorption device and connected to the third adsorption device.

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