Method of decontamination of liquid radioactive waste
(57) Abstract:The invention relates to the field of processing of intermediate level liquid waste from nuclear power plants, nuclear power plants, reprocessing plants, nuclear research centers. The inventive solution srednekraevyh liquid radioactive waste (LRW) adjust the pH to a value of 8-12, create salt content of the sum of inorganic and organic substances is not more than 25 g/l, is introduced into the prepared solution LRW selected fractions of natural sorbent and implement the sorption of radionuclides by mixing the solution of LRW with the sorbent. Then separate the produced radioactive sorbent from the solution by the method of filtration under pressure through ultra - or micro-porous membrane filter with a chemical coating, dropping the sorbent into the drive and cement in Geochemistry stone. Advantages of the method are that it allows you to simplify and reduce the cost of technological process of processing of LRW and facilitates handling of water-salt solutions. 9 C.p. f-crystals. The invention relates to the field of nuclear energy and technology, in particular to the processing liquid intermediate level waste from nuclear power plants, nuclear energy ustanak radioactive waste (LRW) by LRW purification on selective sorbents after pre-treatment of various oxidants and subsequent cementation of radioactive sorbent (Lifanov F. A., Savkin, A. E., Slastnikov Y. T. Purification of high salt liquid radioactive waste by the method of selective sorption. In Proc. of "Radioactive waste. Storage, transportation, processing. The impact on humans and the environment. Abstracts". Proceedings of the international conference, October 14-18, 1996, S.-Petersburg: Administration of S.-Petersburg, CRISM "Prometey", report of the S-21, 1996.). The disadvantages of this method include the need to use special equipment, additional reagents and materials for the oxidation of liquid and recovery of radionuclides released from the oxidation products. Moreover, by implementing the use of expensive synthetic sorbents, the result is a cement compounds with relatively low resistance.The closest technical solution is a method of treatment of liquid radioactive waste, including sorption of radionuclides on natural zeolites and cementing received radioactive zeolites using a knitting system containing granulated blast furnace slag and clay component in a mixture with a solution of sodium silicate (RF Patent 2154317, IPC G 21 F 9/12. Method for processing liquid radioactive waste. Published 10.08.2000 year, the zeolite, the resulting sorption from solution, not containing radionuclides.The authors goal was to eliminate the mentioned disadvantages, to improve the quality of mineral-like matrices, simplify and reduce the cost of technological process of processing of LRW, to facilitate the handling of water-salt solutions.To solve this problem, we propose a method of treatment of liquid radioactive waste, including the preparation of the starting solution LRW, including adjusting its pH to a value of from 8 to 12, the sorption of radionuclides on natural sorbent in static conditions by keeping natural sorbent in a prepared solution of LRW with the preliminary selection of the fraction of natural sorbent.The proposed method differs from the previously known fact that in the prepared solution LRW create the salt content of the sum of inorganic and organic substances is not more than 25 g/l, selected fraction of natural sorbent with a particle size of not less than 0.1 μm, the separation of the resulting sorption of radioactive sorbent from the solution is performed by filtration under pressure through ultra - or micro-porous membrane filter with a chemical coating when the pressure drop across the filter is not less than 4 bar, radioactiv the ora through the membrane filter in the filtering process is supported by no more than 0.2 l/cm2C, the concentration of natural sorbent support of at least 5 g per 1 l of the prepared solution LRW, and sorption of radionuclides spend at least 1 h under stirring.When conducting a multi-stage sorption by additional injection of sorbent into the solution at each stage of sorption of the most complete extraction of radionuclides from solution LRW reach, if the sorbent is injected at least two times. And either separated by filtration radioactive sorbent unite, dropping into the drive and cement in Geochemistry stone by applying the necessary binding system, or each additional maintenance sorbent in the solution obtained at the previous stages of radioactive sorbent is discharged into the drive and also cement. The choice of the binding system is determined by the properties of the used natural sorbent. The criterion for the choice of the sorbent, along with its sorption capacity and availability, is the similarity of the elemental composition and structure of groups of tumors formed in normal humidity conditions of mineral-like yocemento stone. The use of natural sorption materials allows for a small mechanical impact to translate aceski fragile.The technical result of the invention is an integrated solution for the disposal of intermediate level srednekraevyh LRW, which can simplify the treatment of water-salt solutions after removing them Cs-137 and Sr-90, making the main contribution to the radioactivity LRW, to reduce the volume of the resulting solid radioactive waste in the form of mineral-like stone with high water resistance and mechanical strength, are subject to long-term storage and disposal.The method is as follows.In a solution of intermediate level srednekraevyh LRW adjust the pH to a value of 8-12, create salt content of the sum of inorganic and organic substances is not more than 25 g/l, selected fraction of natural sorbent is not less than 0.1 μm and injected into the prepared solution LRW not less than 5 g per 1 l of selected fractions of natural sorbent. Sorption of radionuclides is carried out with stirring solution of LRW with sorbent for at least 1 hour In necessary cases, carry out the above described operation, the introduction of sorbent and sorption under stirring at least twice. Radioactive sorbent is separated from the solution by filtration through ultra - or micro-porous membranes is bent discharge with plasma-chemical coating of the filter gidromolot filtrate and sent for cementing. For the implementation of the last operation prepare knitting mass mixing not more than 30 wt.% radioactive sorbent with the necessary dry ingredients. At lower filtration rate at 70-80% of the initial regenerate the filter, affecting the pulse shot of the filtrate from the hydraulic accumulator filter on the inner surface of the membrane within 3-5 C. the Discharge of the filtrate is due to the atmospheric air, pre-compressed purified water. The result is a sludge discharge from the external surface of the membrane filter. If necessary, the regeneration cycle is repeated.The use of available and cheap natural sorption materials, in particular bleaching of the lands of the mold box and Tripoli Sitestogo field of Kaluga region (TU-2163-001-2612752-94, hereinafter called "Tripoli"), thus demonstrating the advantages of the proposed technical solutions. On the model solutions LRW examined the effectiveness of sorption extraction of the Tripoli radionuclides Cs-137 and Sr-90 at their separate and joint presence in static conditions, the separation efficiency fine Tripoli and sediment from tap water, researched techniques and recipes Immobiliser dispersnogo Tripoli from water by filtration through a microporous membrane filter on a plastic substrate with a chemical coating thickness of 7-12 microns and an average pore diameter of 0.1 to 0.3 μm on the test bench with a working capacity of 40 l have shown the possibility of reducing the concentration of Tripoli in the water with ~5 g/l to <0.001 g/L. Filtering rate for 90 min decreased from 2.2 to 1.7 l/min, with square filter surface ~0.8 m2.Testing at SSC RF-IPPE them. academician A. I. Leypunsky the proposed method of disposal LRW showed that the use of Tripoli and clinoptilolite with a particle size of -80 microns for sorption-membrane extraction of radionuclides Cs-137 and Sr-90 from the water storage facility for spent fuel assemblies provided simultaneous purification of water from Cs-137 and Sr-90 from the level of specific activity of ~106Bq/l to <25 Bq/l, which is below the permissible specific activity of water in accordance with the norms of radiation safety NRB-96. The consumption of sorbent amounted to 15-20 kg/m, the total degree of sorption of radionuclides >99,9996%, the overall purification factor of ~105and the volume of radioactive waste after extraction of Cs-137 and Sr-90 and cementation of radioactive sorbent decreased 25-30 times. Identical results were obtained for LRW with a total salt content of up to 25 g/l, up to 4 g/g decontamination of organic substances, in particular anionic surfactants, Trilon B, oxalic acid and industrial oil at a flow rate of sorbent ~30 kg/m3. Sediment concentrations of sorbate in solution after filtration <<0.001 g/lIP extraction of radionuclides using cheap and available natural materials, separation of radioactive sorbent filtering through legkonastraivaemy membrane filter, characterized by low adhesion of natural sorbents to the membrane material, and cementation of radioactive sorbents together with slimes with the necessary shlakovoza system in mineral-like stones, which has high water resistance and mechanical strength. 1. Method of decontamination of liquid radioactive waste, including the preparation of the starting solution of liquid radioactive waste, including adjusting its pH to a value of 8-12, the sorption of radionuclides on natural sorbent by extracts of natural sorbent prepared in liquid radioactive waste with a preliminary selection of the fraction of natural sorbent, characterized in that the prepared solution of liquid radioactive waste creates salinity amounts of inorganic and organic substances is not more than 25 g/l, selected fraction of natural sorbent with a particle size of not less than 0.1 μm, the Department resulting from sorption of radioactive sorbent from the solution is performed by filtration under pressure through ultra - or micro-porous membrane filter with chemical pokrycia cover and sent for recycling.2. The method according to p. 1, characterized in that the radioactive sorbent discharge with plasma-chemical coating gidromolot filtrate.3. The method according to p. 1 or 2, characterized in that the specific flow of the solution through a membrane filter in the filtering process is supported by no more than 0.2 l/SMS.4. The method according to p. 1 or 3, characterized in that support concentrations of natural sorbent for at least 5 g per liter of prepared solution of liquid radioactive waste.5. The method according to p. 1 or 4, characterized in that the sorption of radionuclides carried out under stirring.6. The method according to p. 5, characterized in that the sorption of radionuclides spend at least 1 h7. The method according to p. 6, characterized in that the sorption of radionuclides carried out by multistage additional injection of sorbent into the solution at each stage of sorption.8. The method according to p. 7, characterized in that each additional introduction of sorbent in a solution of radioactive sorbent removed from the solution.9. The method according to p. 7 or 8, characterized in that it further injected sorbent is at least two times.10. The method according to p. 1 or 9, characterized in that the radioactive sorbent cement using it is
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
FIELD: recovery of liquid radioactive wastes.
SUBSTANCE: proposed method includes treatment of radioactive wastes by heavy-metal ferrocyanide and separation of sediment obtained. In the process liquid radioactive wastes are treated with heavy-metal ferrocyanide formed upon introduction of potassium ferrocyanide and bivalent nickel and/or copper and iron salts taken in amount abundant with respect to stoichiometric quantity. Clarified solution is treated with oxidant upon separation of sediment and filtered through catalytic material containing manganese dioxide. Then filtered-off solution is passed through highly acid cationite in Na-form and highly basic anionite in Cl-form.
EFFECT: enhanced decontamination quality.
5 cl, 1 tbl, 7 ex
FIELD: reactive sorbents.
SUBSTANCE: liquid is conditioned at pH 4-6 and then is brought into contact with chelating ion-exchange resin composed of grafted polyazocycloalkanes at temperature above or equal to 60°C.
EFFECT: enhanced metal removal efficiency.
35 ex, 9 dwg, 9 tbl, 5 ex
FIELD: processing of liquid radioactive wastes.
SUBSTANCE: the proposed method for cleaning of liquid radioactive wastes includes their processing with absorber-sorbent. Ash wastes are used as the absorber-sorbent. The ash wastes are introduced into liquid radioactive wastes in the stage of their neutralization at pH = 0.5-2 at the flow rate, ensuring the ratio of S : L = 1 : (15-50). Then the obtained suspension is separated into the liquid and solid phases.
EFFECT: increased degree of cleaning from radionuclides and enhanced separation rate of produced pulps.
4 cl, 1 tbl, 11 ex
SUBSTANCE: invention relates to application of pectin solution as detergent for skin and hair in radioactive and environmentally hazardous regions. Pectin containing in solution due to chelating action bonds to heavy metal ions to form stable compounds (micelles) having very large size and prevents transferring thereof trough transdermal barrier. Formed micells may be easily removed from human body.
EFFECT: new detergent for skin and hair useful in radioactive and environmentally hazardous regions.
2 ex, 5 tbl
FIELD: methods of the sorption decontamination of waters from the radioactive impurities.
SUBSTANCE: the invention is pertaining to the method of the sorption decontamination of waters from the radioactive impurities. The method of decontamination of the water from radiostrontium includes the treatment of the water with a sorbent based on the burned bauxite ore. At that the ore is burned together with calcium -magnesium lime - CaCO3·MgCO3 and sodium soda salt - Na2CO3 at the temperature of no less than 1200°C and flushed with the water to remove the solvable sodium compounds. It is preferable, that the mixture of the bauxite ore is subjected to burning with calcium-magnesium lime and sodium soda salt in the mass ratio of 1 : 0.55-0.60 : 0.055-0.060. The method ensures an increased effectiveness of removal of the radiostrontium at usage of the initial bauxite ore without lowering of effectiveness of the water decontamination from radiocesium, and also allows to reduce considerably the amount of the spent sorbents, which are subjected to disposal.
EFFECT: the invention ensures an increased effectiveness of removal of radiostrontium from the water at usage of the initial bauxite ore without lowering of effectiveness of the water decontamination from radiocesium, allows to reduce considerably the amount of the spent sorbents, which are subjected to disposal.
2 cl, 10 ex
FIELD: environment control including environment protection in atomic industry.
SUBSTANCE: proposed method for decontaminating radioactive aqueous solutions from radionuclides includes at least one contact of solution with complexing sorbent that has solid-medium immobilized active polymeric layer condensed with chelates. Medium is chosen from following group: activated cellulose; synthetic copolymers with divinyl benzene, activated chloromethyl or hydroxymethyl, or chlorosulfonic groups. Active sorbing layer has ethylenediamine or diethylene tridiamine, or tetraethylene pentaamine, or polyethylene polyamine with copolymers; chelates are chosen from group incorporating carboxyl-containing chelates, phosphonic-group chelates, and hydroxyl-containing chelates. Proposed method enables extraction of radionuclides both in ionic and colloidal condition from solutions doped with highly concentrated impurities; sorbent used for the purpose retains its sorbing properties upon repeated regenerations and is capable of decontaminating solutions both in dynamic and static modes with different pH of solutions being decontaminated.
EFFECT: enlarged functional capabilities.
11 cl, 3 tbl
FIELD: technology of handling of the liquid nuclear wastes of the nuclear fuel and power cycle; methods of reprocessing of the liquid nuclear wastes.
SUBSTANCE: the invention is pertaining to the procedure of the liquid nuclear wastes handling of the nuclear fuel and power cycle and may be used during reprocessing of the liquid nuclear wastes (LNW). The method includes the preliminary concentration, ozonization, microfiltration of the vat residue with fractionation of the permeate and the concentrate and the ion-selective purification of the permeate using the ion-selective a sorbent. At that the microfiltration is conducted at least in two stages: the permeate of each previous stage of the microfiltration is directed to the microfiltration as the source solution for the subsequent stage of the microfiltration, and at the final stage of the permeate from the microfiltration is sent to the utilization. The concentrate produced at each next stage of the microfiltration is mixed with the source solution of the previous stage of the microfiltration. The concentrate produced at the first stage of the microfiltration is directed to the conditioning and dumping. The ion-selective sorbent is added in the permeate of the previous stage of the microfiltration before the final stage of the microfiltration. The invention ensures: reduction of the volume of the liquid nuclear wastes due to the deep purification of the LNW with the high saline share from the radionuclides and extraction of the radionuclides in the compact form of the sparingly soluble compounds at the corresponding increase of the factor of purification of the salts extracted at the stage of the vat residue treatment; reduction and optimization of the consumption of the permeate and concentrate interacting with the source solution as well as produced at the further stages.
EFFECT: the invention ensures: reduction of the volume of the liquid nuclear wastes; the deep purification of the LNW with the high saline share from the radionuclides and extraction of the radionuclides in the compact form of the sparingly soluble compounds at the corresponding increase of the factor of purification of the salts extracted at the stage of the vat resudue treatment; reduction and optimization of the consumption of the permeate and concentrate interacting with the source solution ands produced at the further stages.
FIELD: nuclear-industry radiochemical enterprises for recovering and immobilizing gaseous radioactive wastes.
SUBSTANCE: sorbent used for entrapping radioactive iodine from gas-aerosol stream running from irradiated nuclear fuel cutting-and-dissolving unit has porous base impregnated with nitric acid silver salt (AgNO3); used as sorbent base is porous silicon carbide of 30 to 60% porosity.
EFFECT: enhanced corrosion and mechanical resistance of material in chemically active media.
1 cl, 2 dwg, 3 tbl
FIELD: environmental protection.
SUBSTANCE: invention relates to means and methods of integrated degassing, disinfection, and shielding of sites and zones, where presence of high-activity poisonous substances, poison-gases, chemical weapons, pathogenic microorganisms, their vital activity toxic products, insects (including carriers of human and animal diseases), radioactive substances are revealed or suspected, and also to means and methods to extinguish burning of inflammable liquids and to prevent in inflammation of spills of inflammable liquids. Multifunctional foam composition of invention includes, as active substance, 0.1-5% of didecyldimethylammonium halide clatrate with urea. Use of indicated clatrate provides simultaneous effect of foam compositions, wherein clatrate acts both as multifunctional active substance and as foaming agent. Invention can further be used to eliminate consequences of use of weapons of mass destruction and to eliminate consequences of man-made accidents and emergency situations.
EFFECT: expanded protection possibilities.
24 cl, 3 tbl, 6 ex