Method for determining thorium-234 concentration in seawater
SUBSTANCE: invention refers to radiation ecology and biogeochemistry, and aims at Th concentrating from seawater and determining its concentration. The method for thorium-234 concentration in seawater is implemented in series connected absorbers containing manganese dioxide that is followed by direct radiometric measurements of absorbed 234Th as shown by its primary β-emission. Each absorber works in the radially accurate regimen, which is generated by placing the disk absorber between diaphragms. The analysed water sample is supplied into the central portion of the absorber by means of a diaphragm with a central opening, then migrates to the periphery of the sorbed surface with using the diaphragm with peripheral openings.
EFFECT: varying the sedimentation process rate in the marine reservoirs.
The invention relates to the field of radiation ecology and biogeochemistry, intended for concentration234Th from seawater and the definition of its content that can be used to measure the velocity of sedimentation processes in marine waters.
Thorium-234, which is formed by the decay of uranium-238, is widely used as a natural radiotracer to measure the velocity of the sedimentation processes in the marine environment . Unlike238U, he manifests sorption reactivity and accumulated suspended matter to higher levels. As a result, and also due to the large differences in half-lives of238U (4.5 billion years) and234Th (24.1 d), gravitational removal of biogenic and lithogenic sediment from the upper layer of the water column causes a noticeable deviation of the content of thorium-234 from the equilibrium with uranium-238. This allows us to estimate the rate of sedimentation of the transfer of the various elements in the marine environment [2-4].
In modern Oceanography apply two basic methods of concentration234Th from seawater for subsequent determination of its content radiometric methods: flow-through sorption adsorption and coprecipitation using, in both cases, manganese dioxide as a highly absorptive material .
Method coprecipitation Toria manganese dioxide based on the formation of finely dispersed suspension of microcrystals Mno 2directly in the treated sample of sea water due to chemical reaction between potassium permanganate and douglasites manganese, after which a suspension together with adsorbed on the thorium-234 filtered on membrane filters, and the resulting thin-layer preparations are direct radiometry β-radiation234Th . This allows you to define the content of the234Th relatively small amounts of sea water (20 or less liters), which is the main advantage of this method. However, the coprecipitation no direct control efficiency of extraction of thorium in each sample, which often leads to poor reproducibility of the results obtained . Authors ' methods of such control, atomic-absorption measurements of the amount of manganese dioxide remaining in the tanks for co-precipitation , or by adding samples radiochemical tracer yield, for example,229Th or230Th , are indirect, or require additional radiochemical processing of the received precipitation and concurrent use not only β-, and α-detectors (and sometimes mass spectrometers) to determine the activity of these tracers .
Closest to the claimed method is a method flow-through sorption (see Buesseler K. O., Cochran J. K., Bacon M. P., Livingston, H. D., S. A. Casso, Hirchberg D., Hartman, M. C., A. P. Fleer Determination of thorium isotopes in seawater by non-destructive and radiochemical procedures // Deep-Sea Research. - 1992. - Vol. 39, No. 7/8. - P. 1103-1114). The known method involves pumping water through two serially connected adsorber, made of fibrous material impregnated with micro-crystals of manganese dioxide. The activity of adsorbed234Th is determined by the method of direct counting in his gamma radiation without prior radiochemical extraction of the sorbent, which is the main advantage of this method, along with the possibility of monitoring the efficiency of the sorption of thorium on the difference in activity in the first and second adsorber. It should, however, note that for thorium-234 main is gamma, and beta radiation. Moreover, the output γ-ray234Th energy 63.3 and 92.6 Kev is only 3.8 and 5.4%, respectively. This determines the necessity of handling large volumes of sea water (> 1000 l) for reliable detection of thorium-234 in his gamma radiation, which significantly limits the performance of this method, since the sampling of water supplies, especially from great depths is a time - consuming operation, requiring the use of special samplers, including Autonomous submersible pumps [2, 5]. The time required to process each sample, can be quite value is positive, because the rate of pumping of water through the adsorbers is usually no more than 3-5 l/min . Furthermore, this method requires relatively large adsorbers with an effective volume of 500 cm3. This amount of sorbent cannot be subjected to direct radiometry in most modern γ-detectors without compaction by ashing or pressing under high pressure [2, 5].
The basis of the invention a Method of determining the concentration of thorium-234 in seawater tasked by improving technology, enhance the efficiency of extraction of thorium-234 and the performance of the method.
This object is achieved in that the concentration of thorium-234, dissolved in seawater, perform in the series connected adsorbers containing manganese dioxide and carry out direct radiometry adsorbed234Th his primary β-radiation.
For the practical implementation of this approach must be considered that β-radiation has far less penetrating power compared to γ-quanta. In this regard, for direct β-radiometric determination of thorium234Th in the adsorbers, their shape and dimensions must be chosen in such a way as to minimize the effect of self-absorption of β-particles in the thickness of Sorbi the existing material and to ensure that thus, a sufficiently high efficiency of sorption of thorium from sea water. To solve the first problem, the most acceptable are the adsorbers in the form of thin disks, which provides optimal geometry accounts β-particles accumulated in them thorium-234 using gas discharge, gas flow and liquid-scintillation detectors, the most commonly used in Oceanographic practice. However, the disk shape of the adsorbers is not optimal to ensure high efficiency of sorption in flow regime due to the small residence time of the recoverable element in a thin layer of sorbent material. To eliminate this disadvantage it is proposed to use the disk adsorbers are not straight and radially precise mode in which the processed sample arrives not on the entire surface of the disk adsorber, and only in its Central part and then flows to the periphery of the absorbing layer, greatly increasing the contact time with it dissolved thorium. Structurally, this is achieved by using the input and output apertures, the first of which has a hole in the Central part of the water, and the second slits along the edges to discharge treated leachate (Fig. 1).
The invention is illustrated by illustrations. In Fig. 1 shows a Scheme for determining the concentration of the emission of thorium-234 (, Bq/l) in sea water; Fig. 2 - Installation for the extraction of thorium-234 in seawater.
To implement the method, the authors have improved disk adsorber for the implementation of sorption in accurate radial mode. The adsorber contains (see Fig. 1) the upper part of the housing 1, the input aperture with a Central hole 2, disc adsorber 3, impregnated with manganese dioxide; output aperture 4 with the slots on the periphery of the lower part of the housing 5. White dotted arrows show the direction of radial water flow through the disk canister.
An example implementation of the method.
Samples of surface waters from the waters of the Sevastopol Bay with a capacity of 20 l were collected in plastic containers. For the extraction of thorium-234 in seawater was used by the installation (see Fig. 2) containing the peristaltic pump, connected in series prefilter adsorbers 1 and 2, 3. The arrows indicate the direction of water movement. In the foreground: disk sorbent impregnated Mno2(in the Cup on the left) and the polypropylene-based sorbent before impregnation (Cup on the right), used as prefilter. At the bottom of the insert is shown the body of the absorber disassembled. Using a peristaltic pump water was pumped through the disk prefilter for separation of suspended fraction of thorium, then through two successively the United States is x disk adsorber, impregnated with manganese dioxide intended for concentration of dissolved thorium. Prefilter and adsorbers have the same diameter (25 mm) and thick (3-4 mm), and were made of extruded polypropylene fiber material density of 0.33 Pol3. The nominal pore size of this material was about 0.5 μm. For impregnation of adsorbers, manganese dioxide them maintained in a saturated solution of potassium permanganate, pre-adding 25% aqueous ammonia solution as an alkaline buffer. For better impregnation of the fibrous material of the adsorbers, the solution was heated to 30-40°C. and maintained for 2-3 hours. After this was added concentrated aqueous solution douglasthe manganese rate of 1 volume part nl22 parts KMPO4. At the same time, the thickness of the polypropylene disk was accompanied by the formation of micro-crystals of manganese dioxide by the reaction:
After purchasing the disk dark brown (the color of the manganese dioxide), they were washed with distilled water, kept at room temperature for up to drip-dry and were placed in a Plexiglas housing adsorbers, consisting of two cone-shaped parts with threaded connection (see Fig. 1). Each part of the body is provided with nozzles for the evaluation of the Yes water or drainage of the filtrate. The tightness of the threaded connection is achieved by a sealing ring made of chemically resistant rubber. In the input part of the body is fixed to the diaphragm with a Central hole, and in the output panel aperture with a peripheral slots. Between the two diaphragms placed the disk canister.
After pumping the entire sample volume, the prefilter and the adsorbers were removed from buildings and transferred into 20-ml polyethylene vials for liquid scintillation spectrometry. Vials with adsorbers added 1-2 ml of 6M hydrochloric acid and was heated to 50-60°C. Under these conditions, the manganese dioxide was completely transformed into dissolved chloride of manganese and thorium were desorbable. Then in the vials was added 15 ml of scintillation fluid Optiphase-III (UK) and carried out measurements of the concentration of thorium-234 using a liquid scintillation analyzer QUANTULUS-1220 (LKB Wallac, Finland). The efficiency of sorption of thorium disk adsorbers was calculated by the formula:
where RAand Rb - activity234Th in the first and second adsorbers (Bq). The initial concentration of thorium-234 in seawater (Bq/l) was determined by the equation:
where V - volume of sample (l).
Testing of the proposed Method of determining the concentration of thorium-234 in Mor is some water was performed in the waters of the Sevastopol Bay in different seasons 2009 This gave the opportunity to carry out measurements234Th at different levels of suspended matter due to seasonal dynamics of phytoplankton and receipt of terrigenous sediment to the coastal runoff. Tests showed that when using disk adsorbers of these dimensions is quite high (>65 %) the degree of extraction of thorium-234 from 20-liter samples of surface waters of the Black sea when the initial concentration of 1.6·10-3up to 2.2·10-2Bq/l, i.e., in the whole range of values of the content of the234Th, known for this reservoir.
The advantages of the proposed method lies in the fact that by using a relatively small sample volumes (about 20 l) you can control the efficiency of extraction of thorium-234 without the use of expensive radiochemical tracer yield and additional instrumentation.
Sources of information:
1. U.S. GOFS. Sediment trap technology and sampling // U. S. Global Ocean Flux Study. Planning Report No. 10 of the Working Group on Sediment Trap Technology and Sampling / Eds. G. Knauer, V. Asper. - Woods Hole (USA): WHOI, 1989. - 94 p.
2. Buesseler K. O., Cochran J. K., Bacon M. P., Livingston, H. D., S. A. Casso, D. Hirschberg, M. C. Hartman, A. P. Fleer Determination of thorium isotopes in seawater by nondestructive and radiochemical procedures // Deep-Sea Research. - 1992. - Vol. 39, No. 7/8.-P. 1103-1114.
3. Gulin S. B. Seasonal changes of234Th scavenging in surface water across the western Black Sea: an Memorandum of the cyclonic circulation patterns // Journal of Environmental Radioactivity. - 2000. - Vol. 51, No. 3. - P. 7-19.
4. Waples, J. T., Bnitez-Nelson C, Savoye N., Rutgers van der Loeff M, Baskaran M, Gustafsson 0. An introduction to the application and future use of234Th in aquatic systems // Marine Chemistry. - 2006. - Vol. 100. - P. 166-189.
5. Rutgers van der Loeff M., Sarin M. M., Baskaran, M., Benitez-Nelson C, Buesseler K. O., Charette M., Dai, M., Gustafsson O., P. Masque, P. J. Morris, K. Orlandini, Rodriguez y Baena Α., Savoye N., Schmidt, S., R. Turnewitsch, V6ge I., Waples, J. T. A review of present techniques and methodological advances in analyzing234Th in aquatic systems // Marine Chemistry. - 2006. - Vol. 100. - P. 190-212.
6. Buesseler K. O., Benitez-Nelson C, Rutgers van der Loeff M, J. Andrews, L. Ball, G. Crossin, M. A. Charette An intercomparison of small - and large-volume techniques for thorium-234 in seawater // Marine Chemistry. - 2001. - Vol. 74. - P. 15-28.
7. Pike, S. M., Buesseler K. O., Andrews J., Savoye N. Quantification of Th-234 recovery in small volume seawater samples by inductively coupled plasma-mass spectrometry // Journal of Radioanalytical and Nuclear Chemistry. - 2005. - Vol. 263 - P. 355 to 360 above.
The method of determining the concentration of thorium-234 in seawater, comprising pumping a measured sample of water through two serially connected disk adsorbers, impregnated with manganese dioxide, and the control efficiency of extraction of thorium-234, characterized in that exercise radiometric determination of thorium-234 by default ß-radiation in the adsorbers, each adsorber operates in accurate radial mode, which provides by placing the disk adsorber between the diaphragms with slits, and the sample water flows in the Central part of the adsorber using a diaphragm with a Central hole, then it is served to the periphery soubirou the it layer by using a diaphragm with a peripheral slots.
SUBSTANCE: method comprises removing tritium from irradiated beryllium, dissolving beryllium in acid, adding a complexing agent (preferably diethylenetriaminepentaacetic acid (DTPA) or ethylendiaminetetraacetic acid (EDTA)), adding ammonia to precipitate beryllium hydroxide, converting the amorphous form of the beryllium hydroxide precipitate to a crystalline form, e.g., by prolonged heating in ammonia solution, separating the ammonia solution from the beryllium hydroxide precipitate by centrifuging or filtering. The separated beryllium hydroxide precipitate can be re-dissolved in acid and subjected to said treatment steps until the required degree of purity is achieved.
EFFECT: low radioactivity of highly active beryllium wastes, which enables re-fabrication and recycling thereof.
FIELD: engines and pumps.
SUBSTANCE: proposed pump comprises housing with intake ball valve, pulse duct, pressure pipe with discharge ball valve, air pressure control valve and control system. Housing is communicated with lower nozzles via pipe and lower nozzle chamber accommodating the shaft with cone connected thereto over small diameter. Cone is connected over large diameter to the shaft hollow part with nozzles. Flange is made at the cone large diameter to interact with chamber seat at the shaft top position. Said shaft is engaged via moving bearing assembly and gear with nozzle turn sand penetration drives.
EFFECT: control over flow rates of fluid fed simultaneously into lower nozzle chamber and pressure line.
3 cl, 5 dwg
FIELD: engines and pumps.
SUBSTANCE: invention relates to nuclear industry in part of nuclear wastes processing, namely, to devices for more complete discharge of radioactive residue from storage reservoirs, and may be applied in chemical, petrochemical and other industries. A pump comprises a body, an air distributor, comprising valves of compressed air supply, spent air discharge and underpressure supply into a body, a pulse line, an injection pipeline with an outlet ball valve, a control system and an inlet valve. The inlet valve is equipped with a slide valve interacting with the end of a seat made in the form of a pipe and connected by a shaft with a pneumatic cylinder stem. Suction nozzles are connected to bottoms of bodies along the perimeter, at the end of which there are slots that expand inside, and plugs are fixed to the ends. According to one of the versions, the pneumatic cylinder is installed in the service zone and is connected to a control system, electric pneumatic distributors of which that control operation of the underpressure supply valve and the pneumatic cylinder of double-sided action are connected in parallel. According to the second version, the pneumatic cylinder is installed on the pump body, and the upper cavity of the pneumatic cylinder is connected by a pipeline to the pulse line. In the lower cavity of the pneumatic cylinder there is a return spring installed, the force of which is less than the force of the pneumatic cylinder at working pressure and makes at upper and lower positions of the pneumatic cylinder pistons of accordingly 0.4 and 0.6 of the pneumatic cylinder force.
EFFECT: development of a device for more complete discharge of radioactive residue from storage reservoirs.
6 cl, 3 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to processing of radioactive wastes and can be used for cleaning of secondary platinum with radioactive plutonium contamination. Proposed method comprises heating of secondary platinum scrap contaminated with plutonium over its entire volume and with metallic impurities in surface layer in amount larger than that of plutonium. Prior to scrap heating, impurities are removed by hydrometallurgy processes, not destructing the platinum surface. Scrap is heated to its fusion with formation of radioactive condensed plutonium oxide and subjected to inductive melting of the platinum to its separation from plutonium oxide. Melting is carried out in the presence of fluxing additives with the formation of melt and slag containing plutonium oxide at melt heel area-to-melt volume ratio of 0.20-0.50, electromagnetic field frequency of 20-66 kHz and air blowing to melt surface at 2049-2073 K for 1.0-1.3 h. Then, slag is removed from platinum.
EFFECT: facilitated plutonium oxide formation, preservation of platinum.
7 cl, 1 tbl
SUBSTANCE: invention relates to nuclear industry and can be used to decontaminate inner and outer surfaces of equipment. In the present invention, the equipment to be decontaminated is placed in a decontaminating solution and then exposed to ultrasonic vibrations, wherein the vibrations are excited in the entire volume of the equipment by providing hard acoustic contact of the surface of the equipment with acoustic ultrasonic radiators, wherein the vibrations are excited in form of pulses with filling frequency which corresponds to resonance frequency of radiators mounted on the equipment. The apparatus for realising the disclosed method comprises a container with the decontaminating solution, supports placed in the container for mounting the equipment to be decontaminated, an electric generator whose output is connected to the acoustic ultrasonic radiators, partially immersed in the solution; the radiators are equipped with waveguide-concentrators and are mounted on the back side in a clamp cover, which, through a weight load, provides hard acoustic contact of the waveguide-concentrators with the surface of the equipment.
EFFECT: enabling decontamination of objects with an inner cavity.
2 cl, 1 dwg
SUBSTANCE: method involves immersing at least one heat-dissipating capsule into a well formed in geologic formations. A heat-conducting array saturated with radionuclides is placed inside the capsule with an airtight casing. The average density of the capsule with radioactive wastes is higher than the density of the rocks under the capsule. The melting point of the refractory material from which the airtight casing of the capsule is made is higher than that of the rocks under the capsule. The quantitative composition of the mixture of radionuclides inside the casing is selected based on the condition that, the power of volumetric heat release of the radioactive wastes should be higher than the heat power needed to melt the rocks under the capsule. Content of the highly active isotope in the mixture of radionuclides filling the capsule is selected based on the condition: qmin≥1.2 W/cm3, where qmin is the minimum power density of volumetric heat release of the mixture of radionuclides 10 years after immersing the capsule.
EFFECT: enabling relatively fast disposal of the entire range of radioactive wastes, including long-lived radionuclides, irreversible dissolution of radionuclides.
20 cl, 1 dwg
FIELD: power industry.
SUBSTANCE: invention refers to a deactivation area of solid radioactive wastes, processing of liquid radioactive wastes and fixation of radioactive elements in a stable solid medium. Deactivation of inner surfaces of tubes is performed by means of a suspension with humidity of not less than 50%, which contains an abrasive component of up to 20% of clay weight, diatomite of up to 25% of clay weight and phosphoric acid in the amount of (20-25)% of clay weight.
EFFECT: invention allows simplifying deactivation.
SUBSTANCE: decontamination is performed in two steps: at the first step, steam activated with chemical reagents is fed into a decontamination chamber with contaminated materials heated to 110°C; at the second step, the decontamination chamber is cooled and the decontaminated material is treated with solutions of organic solvents and complexing agents in a medium of liquefied gases or low-boiling solvents. The method may involve successively using multiple treatment cycles, alternating the first and second steps.
EFFECT: high decontamination efficiency, increasing the decontamination factor 4-30 fold compared to a single-step decontamination method in supercritical fluids, low operating pressure and volume of liquid radioactive wastes and shorter decontamination time.
3 cl, 1 dwg
SUBSTANCE: method of treating spent Petryanov fabric-based filters involves contact thereof with an organic liquid which dissolves filter material, separating solid aerosol particles accumulated on the filter, from the formed Petryanov fabric solution, depositing filter material followed by separation thereof from the solution and regenerating the solvent. The accumulated solid aerosol particles are industrially recycled substances. The organic liquids which dissolve filter material are preferably butyl cellosolve, methylene chloride and xylenes. The filter material precipitant used is in form of liquids which are infinitely miscible with the solvent and do not dissolve filter material, preferably water, alcohols and saturated hydrocarbons. The solvent is regenerated by low pressure distillation.
EFFECT: providing dust-free dismantling of filters, multifold reduction of the amount of wastes to be buried.
5 cl, 6 ex
FIELD: power industry.
SUBSTANCE: wastes are stored in a warehouse, cavities in the warehouse are filled with quartz sand, and then, outside the warehouse there erected is a protective shelter of mount type from different materials; at that, as the warehouse there used is a reactor building; wastes and building structures are stocked in the rooms of the building; sand is supplied simultaneously outside and inside the building, outside till natural angle of slope is formed and inside, starting from lower floor till all cavities in each room are filled. Besides, sand is also simultaneously supplied to all rooms of each floor at least with two jets at radial speed till they touch each wall of each room; at that, jets are rotated in one and the same horizontal plane at the ceiling in the centre of each room.
EFFECT: invention allows obtaining radiation safe object of continuous disposal at considerable reduction of labour and material costs and completely restoring the environment of the object location area.
SUBSTANCE: claimed invention relates to system for purification of wastes flow, mainly liquid or water radioactive wastes, for their safe utilisation and converting them into one or two forms, including water form for safe discharge into the environment and hardening form for safe utilisation. Realisation of claimed invention includes realisation of five steps, designated as I-V. Synchronisation of selection of sorbent substances and multirecycle option for separation of target substances from wastes flow is included as stage of step II (sorption and isotopic recovery by means of powder sorbent). Other steps correlate with sorption step (II), including oxidation (I) to deactivate or destruct existing chelating agents, solid-liquid separation (III) and selective ion exchange (IV) to achieve final desirable result of wastes flow processing. Final step consists in final processing (V).
EFFECT: possibility of obtaining predetermined specific strategy for target element by means of synchronisation of selection of sorbent substances ad multicycle option for removal of target substances from flow of radioactive wastes.
28 cl, 1 dwg
SUBSTANCE: invention relates to field of recycling of radioactive solutions. Composition of extraction chromatographic material for selective separation of U(VI), Th(IV), Np(IV) and Pu(IV) from nitric acid solutions contains three components. As complexants composition contains 33% of methyltrioctylammonium nitrate (MTOAN) and 1-16% of phosphoryl podand. As matrix composition contains macroporous spherical granulated copolymer of styrene with divinylbenzene. As phosphoryl podand used are derivatives of 1,5-bis[2-(oxyethoxyphosphoryl)-4-(alkyl)phenoxy-3-oxapentane of general formula I , where Alk is alkyl C1-C12.
EFFECT: extension of spectrum of highly efficient selective sorbents for extraction of U(VI), Th(IV), Np(IV) and Pu(IV) from nitric acid solutions.
SUBSTANCE: invention relates to radio analytical chemistry and can be used to monitor content of radionuclides in fresh and sea water, in urine of individuals exposed to radiation and in samples of different process solutions. The method of extracting radionuclides from aqueous solutions includes filtering the solution through a selective sorbent placed in the drip chamber of an apparatus used for intravenous transfusion of infusion solutions and preparing an agent suitable for gamma-ray spectrometry.
EFFECT: faster method while maintaining high efficiency and reducing measurement errors and distortion of results due to absorption of the measured gamma-radiation by filters.
2 cl, 3 dwg
SUBSTANCE: invention relates to sorption extraction of caesium radionuclides from aqueous solutions. The method of extracting caesium radionuclides includes filtering an aqueous solution through a selective sorbent which is iron-potassium ferrocyanide on a support, desorption of caesium from the sorbent with an alkaline solution containing Trilon B and potassium oxalate. The eluate obtained from desorption is further filtered through a sorbent which is nickel-potassium ferrocyanide.
EFFECT: faster caesium extraction and minimal volume of obtained concentrate containing caesium radionuclides.
1 tbl, 2 ex
SUBSTANCE: invention relates to sorbents produced on the basis of fly grit microspheres of thermal electric power stations and can be used for removal of radio nuclides from liquid wastes. Synthesis of sorbent comprises deposition of active component on the surface of microspheres by mixing the latter with alkaline metal ferrocyanide solution (arrester), removal of excess arrester solution whereby arrester volume retained by microspheres is defined. Transition metal salt solution is added to the mix of microspheres and arrester to hold the mix to phase separation. Thereafter liquid phase is removed while obtained sorbent is dried. In compliance with second version, sorbent synthesis comprises processing of microspheres with the solution of vanadium, or zirconium or tungsten salts and removal of excess solution whereby salt solution volume retained by microspheres is defined. Thereafter, alkaline metal ferrocyanide solution (arrester) is added thereto, excess arrester solution is removed to hold the mix to phase separation. Thereafter liquid phase is removed while obtained sorbent is dried. In compliance with both versions, sorbent is dried at 60-80°C for 1-2 hours or at a room temperature for 15-20 hours.
EFFECT: efficient removal of cesium, cobalt, cerium, europium, etc.
11 cl, 6 dwg, 6 ex, 1 tbl
SUBSTANCE: invention relates to safe operation of nuclear power plants. Content of uranium in process media of nuclear power plants is controlled as follows: collecting a sample of the process medium, alkanising said sample to pH 9-11 by adding ammonia, filtering through a cellulose acetate membrane with freshly deposited manganese dioxide, dissolving the membrane with manganese dioxide in hydrochloric acid while boiling, reducing uranium with ascorbic acid and zinc metal to oxidation state IV, and then determining content of uranium in the solution using a photometric method using arsenazo III in a chloride medium.
EFFECT: simple and faster control, lowering the uranium detection limit 40-fold.
SUBSTANCE: radionuclides and toxic metal ions are removed from water using sorbents in form of gaize crumbs with diameter of 20-50 mm.
EFFECT: invention enables to avoid intermediate operations and use of deactivating substances.
FIELD: power engineering.
SUBSTANCE: method to decontaminate liquid wastes containing one or several radioactive chemical elements to be removed, including the following stages: the stage of putting in contact the liquid wastes with the solid particles in the first reactor; the stage of suspension settling in the second reactor, as a result of which the solid phase is produced, and the liquid phase; the stage of separation of the specified solid phase and the specified liquid phase, a part of the specified solid phase produced after the stage of settling is repeatedly sent into the first reactor for realisation of the stage of putting in contact.
EFFECT: invention makes it possible to improve efficiency of decontamination.
6 cl, 1 dwg
FIELD: power engineering.
SUBSTANCE: invention relates to the technology of handling liquid radioactive wastes (LRW) of nuclear power plants (NPP) and may be used in process of recycling of floor drains and still bottoms of NPP LRW for removal of the radio nuclide 60Co with its concentration in the solid phase. The method to extract the radionuclide 60Co from liquid radioactive wastes of the NPP includes introduction of iron cations (III) and nickel cations (II) into the solution at the mole ratio of 1:1 and potassium ferrocyanide at the mole ratio with iron cations (III) from 2:1 to 4:1.
EFFECT: invention makes it possible to simpligy the process of extraction of radionuclide 60Co from NPP LRW, to reduce time of its performance.
SUBSTANCE: disclosed is material which contains polyazacycloalkane which is grafted on polypropylene fibre, a method of producing said material and a method of removing metal cations from a liquid by bringing said liquid into contact with said material.
EFFECT: disclosed material combines excellent selectivity of binding heavy metals, lanthanides or actinides with excellent operational characteristics.
55 cl, 6 dwg, 9 tbl, 8 ex
FIELD: recovery of liquid radioactive wastes.
SUBSTANCE: proposed method includes bringing liquid radioactive wastes in contact with matrix saturated with selective ion-exchange material (solid extracting agent). Glass-crystal material with open porous structure is used as matrix for the purpose. Matrix material is produced from hollow glass-crystal cene spheres formed from mineral particles of volatile ash produced as result of black coal combustion and saturated with selective ion-exchange material.
EFFECT: facilitated procedure of radionuclide extraction.
5 cl, 1 tbl, 5 ex