Method for processing weapons-grade highly enriched uranium and its alloys in the fuel material for use in nuclear reactors
(57) Abstract:Essence: highly enriched uranium is oxidized by oxygen in the air, and then produce the fluorination with elementary fluorine at its excess above the stoichiometric 5 - 50%. Received hexafluoride purified by the method of centrifugal separation with subsequent offset with 235 uranium hexafluoride, the content of which is lower than in the fuel material, by shifting the gas streams of high - and low-enriched uranium hexafluoride. At the final stage of the product before packaging Desublimers. 4 C. p. F.-ly, 1 Il. The invention relates to a method of eliminating nuclear weapons by processing weapons-grade highly enriched uranium metal and its alloys for further use as fuel in nuclear reactors.Highly enriched uranium is a uranium with an enrichment of u-235 above 20 wt. low enriched uranium from 1.5 to 5 wt. raw uranium 0,711 wt.Known methods of processing uranium metal are generally to the processing of natural uranium or reprocessing of spent nuclear fuel.Thus, known methods of processing after the s impurities and separation of elements, included in spent nuclear fuel. The end product of these processes is uranium oxide 
There are ways to recycle fuel from uranium or oxide fluoride methods, as liquid solutions or melts of salts, and in the gas phase. The end product of these processes is uranium hexafluoride 
Known methods of processing natural or depleted uranium, which include both obtaining uranium oxides and getting hexafluoride 
There are also known methods of processing enriched uranium (uranium-235 up to 4 wt.), in which the main problems are the issues of nuclear safety and loss prevention uranium-235 
All known methods do not solve the basic problem of the invention, which consists in the elimination of weapons-grade (containing uranium-235 80-94 wt.) highly enriched uranium metal and its alloys and bring it to fuel nuclear reactors that meet international standards [2, 3]
In known publications [4, 5] discusses aspects of the removal or destruction of "specific attributes" (original form) of weapons-grade highly enriched uranium metal after the dismantling of nuclear weapons, different adreaction.The closest in technical essence and the achieved effect is a method for processing weapons-grade highly enriched uranium metal and its alloys in the fuel material for use in nuclear reactors. The method involves the oxidation of a metal highly enriched uranium mixed oxide of highly enriched uranium from natural uranium oxide fluorination of a mixture of oxides, purification of enriched uranium hexafluoride two-stage distillation, obtaining low-enriched uranium hexafluoride by mixing purified hexafluoride uranium hexafluoride uranium up to 5% enrichment by weight of the final mixture of 5% hexafluoride with natural uranium hexafluoride and packing finished product in cylinders "30" 
The disadvantage of this method is the multistage process of mixing, first at the stage of the oxides, and then at the stage hexafluoride.Preliminary mixture of oxides of highly enriched uranium with natural can be explained by the inability to clean in the distillation apparatus of the highly enriched uranium due to the fact that these devices according to their design features do not have adenomatosnuu configuration, which leads to low t is sociologistswho uranium water (liquid) technology, that is undesirable because of the emergence of liquid radioactive waste and the introduction of a neutron moderator (hydrogen and carbon), and increase the probability of spontaneous nuclear chain reaction.The aim of the invention is the elimination of nuclear weapons by processing highly enriched weapons-grade uranium and its alloys for use of products of processing as a fuel source for nuclear reactors.A high degree of enrichment of weapons-grade uranium (85-97 wt. uranium-235) made additional adjustments to the task, namely, the need for safeguards for the prevention of spontaneous nuclear chain reaction at all stages of processing, which resulted in severe restrictions on the geometric dimensions of the equipment used.In addition, the aim was to improve technological process and eliminate the appearance of liquid radioactive waste in the processing of highly enriched weapons-grade uranium.This is solved by the creation of a method of processing weapons-grade highly enriched uranium metal and its alloys in the fuel material for use in nuclear reactors, including the oxidation of highly enriched metal the material for use in nuclear reactors by mixing hexafloride different degrees of enrichment with subsequent filling of the fuel material in the container, in which, according to the invention, the oxidation of uranium metal carry oxygen at a temperature of 700-1100aboutWith, followed by fluorination of the resulting oxides of uranium elemental fluorine in excess of fluoride greater than stoichiometric at 5-50 wt. then the enriched uranium hexafluoride purified by the method of centrifugal separation, followed by mixing it with uranium hexafluoride containing uranium-235 below content in the fuel material, by continuously combining the two gas streams, and the resulting fuel material before filling Desublimers (Fig. 1).Optimal methods of fluoridation are: fluoridation of highly enriched uranium oxides at a temperature of 300-400aboutWith under stirring and the excess of fluoride above the stoichiometric 5-10% and fluorination at a temperature of 1400-1500aboutWith in excess of fluoride greater than stoichiometric by 10-50% with the introduction of the oxides in the reaction zone at a gas-carrier.Purification of highly enriched uranium hexafluoride carried out by the method of centrifugal separation cascade of gas centrifuges to impurity content of 10-4-10-5wt.The offset of the two gas streams is carried out by reeved metal weapons-grade uranium hexafluoride conduct dry methods i.e. without the use of a liquid technologies in devices adrenoreceptor execution.The temperature oxidation 700-1100aboutWith the organization of the cyclical process of heating-cooling allows to speed up the process of obtaining uranium oxides and thereby improve the efficiency of the process due to self-cleaning of the surface of uranium metal at the moment of transition from the modification and reduction of the metal by 0.7% Temperature - transition varies depending on the presence of alloying elements from 720 to 810aboutC. When conducting the oxidation below 700aboutWith the process slows down and becomes unproductive, because on the surface of uranium metal forms a dense oxide film, impeding the flow of oxygen to the reaction surface. When the temperature oxidation from 700aboutWith up to 1100aboutWith monotonically increases the rate of oxidation.Increasing the process temperature above 1100aboutWith can lead to uncontrolled burning of uranium (due to ekzotermicheskie oxidation process), its melt, failure of equipment and violation of nuclear safety.From this point of view for oxidation of uranium metal and its alloys riodic to similar consequences, as the temperature increases above 1100aboutC.After a transaction, oxidation of the resulting oxides (nitrous oxide) uranium pulverized and subjected to fluorination.Choice as a fluorinating agent of elemental fluorine is caused by the necessity of obtaining uranium hexafluoride, which is impossible to obtain when interacting with other fluorinating agents, for example, with hydrogen fluoride.The temperature of the fluorination is not the determining factor for the decision of a task of the elimination of nuclear weapons by processing highly enriched weapons-grade uranium and its alloys and the use of products of processing as a fuel source for nuclear reactors. Although fluoridation of highly enriched uranium oxides will occur at any temperature in the range from 200 to 1600aboutWith the correct choice of temperature fluorination allows to optimize both the process of fluoridation, and the process of purification of uranium hexafluoride.Therefore, an additional difference of the proposed method against known is the choice of modes of fluoridation, which depends on many factors, such as the composition of highly enriched uranium, i.e., the presence or the and etc.Thus, low-temperature fluorination at 300-400aboutWith is selected in the presence of uranium oxide appreciable quantities of alloying components, which at these temperatures do not form volatile fluorides and can be separated at this stage of uranium.Choice of excess elemental fluorine from 5 to 10% above the stoichiometric at a low temperature mode fluoridation due to larger area of contact time fluorination. The process will go and when large quantities of fluoride, up to 50% above stoichiometric, but with a greater amount of fluoride that is returned in the beginning of the process, will be contaminated with harmful impurities, which is undesirable.If necessary, increase the speed and performance of the fluorination process, as well as the processing of highly enriched uranium oxide not containing significant quantities of alloying components, uses a high temperature method of fluorination at a temperature of 1400-1500aboutWith and excess fluorine 10-50% above stoichiometric. In this case, powdered uranium oxide is fed into the flame reactor for gas-carrier, for example, nitrogen.Choice of excess elemental fluorine from 10 to 50% above the stoichiometric is italinate to 3 kg/ h process established, thus it is necessary to maintain an excess of fluoride in proportion to productivity growth.When excess fluoride less than 10% is not ignition of the reaction mixture. The excess over 50% impractical because of the difficulties arising from the utilization and conversion of fluorine. This method also lends itself well to automation and spacing.Gaseous enriched uranium hexafluoride may be contaminated with fluoride, molybdenum, tungsten, rhenium and other gaseous impurities.The choice of method of centrifugal separation cascade of gas centrifuges for cleaning highly enriched uranium hexafluoride due to the possibility of the release of highly enriched uranium hexafluoride from all without exception gaseous impurities with molecular weight less than the molecular weight of the uranium hexafluoride, the construction of the treatment cascade is adenomatosnuu that allows you to clear the uranium hexafluoride the highest enrichment (up to 97 wt. uranium-235) and to use only single-stage mixing.Highly enriched uranium hexafluoride, cleaned up their content 10-4-10-5wt. centrifugal cleaning stage.Then the purified gaseous enriched uranium hexafluoride is mixed with uranium hexafluoride containing uranium-235 below content in the fuel material. This is another distinctive feature of the invention in comparison with the prototype, which is that not only change methods of operations and their modes, but the sequence of these operations. So, instead of the three operations of mixing in the method-prototype stage after oxidation, during and after fluorination, in the method according to the invention uses only one operation of mixing after purification of highly enriched uranium hexafluoride. The choice of a particular composition hexafluoride to mix it with the highly enriched uranium hexafluoride is associated with the content of uranium-235, the amount of undesirable impurities uranium-234 and uranium is 236 and the composition and amount of the fuel material.When mixing highly enriched hexafluoride, for example, 97 wt. uranium-235, if necessary, obtain the composition of the fuel material, for example, 80 wt. uranium-235, can be rented for mixing hexafluoride containing uranium-235 from 79% to hexafluoride urial, i.e. the more ready of the fuel material to be obtained, the greater the degree of enrichment should be the second mixed stream.On pipelines installed regulating the flow devices that allow greater precision in adjusting the composition of the finished product, avoiding getting married.Mixed uranium hexafluoride Desublimers, stariway vessel, heated to 90-110aboutC, incubated for 4 h (homogenized) and pour in the tank "30".P R I m e R 1. In the apparatus for oxidation downloaded item products from weapons-grade highly enriched uranium metal that has been contaminated by plutonium (U mass not more than 6000 g) were heated to 900aboutWith the flow of air and stood up to full oxidation.The resulting uranium oxides were crushed and fed into a horizontal reactor for low-temperature fluorination with periodic stirring.In the process of heating up to 300aboutWith consumption and fluoride 5-10% of the stoichiometric formed oxychoride uranium that with increasing temperature up to 400aboutTo turn into uranium hexafluoride. Access to the hexafluoride reaches 97,9% utilization of fluorine 85-90%
raised in a centrifugal cascade (cascade of gas centrifuges), where is cleaned from the fluorides of the elements with molecular weight below the molecular mass of uranium hexafluoride.Cleared up to 10-4-10-5wt. the uranium hexafluoride is served in the collection of the purification cascade and forth on desublimation. From the installation of desublimate highly enriched uranium hexafluoride enriched to 90% u-235 in the gas phase through the flow metering device is fed into a manifold mixing. There through the flow metering device is uranium hexafluoride enriched to 1.5% uranium-235.Consumption of highly enriched uranium hexafluoride is 0,3388 g/s, and low-enriched 9,6612 g/S. the merger of the two streams and their mixing received the product yield is equal to 10 g/c with a concentration of 4.4% uranium-235. Gaseous product Desublimers, sativa his vessel, heated to 90-110aboutC, incubated for 3-6 h at this temperature and poured into cylinders "30" as the fuel material.P R I m m e R 2. Oxidation of weapons-grade highly enriched uranium metal, not containing impurity elements was carried out in accordance with example 1. The resulting milled uranium oxides was applied in the horizontal reactor is and 15-17% Yield of uranium hexafluoride reaches approximately 98% utilization of fluorine 40-44%
The resulting uranium hexafluoride is cleaned of the residual unreacted fluoride by desublimate and then is further processed without purification cascade of gas centrifuges.Unreacted fluorine after cleaning is sent to the reactor for fluorination for reuse.P R I m e R 3. In the apparatus for oxidation download detail products Armory alloy on the basis of highly enriched uranium by weight of less than 6000 g, the installation was sealed, was provided by the air and heated to 700aboutC. In the process of heating and air supply uranium due to ekzotermicheskie oxidation process is heated to the phase transition temperature of uranium-modification (772aboutC). This was accompanied by a decrease in volume of the metal and salootdelenie oxide film from the metal surface. When the temperature reached 800aboutWith the heating turned off.On the oxidation of metallic uranium by weight of 6000 g spent 5 hours Extracted from the apparatus of oxidation of the oxide of highly enriched uranium were crushed in a mill, then on the gas-carrier (nitrogen) was applied to the feeder-dispenser for aeration followed by continuous transportation of the mixture in the reaction zone flame reactor flare Toya on stoichiometry, lit the torch and set the temperature of 1400-1500aboutC. the Rate of fluorination was 5 kg of oxide in 1 ch. Output of uranium hexafluoride per cycle achieved 99.9% of
To reduce the speed of fluoridation to 3 kg/h it is necessary to reduce the flow of elemental fluorine to more than 10% required by stoichiometry, and to increase the rate of fluorination above 5 kg/h it is necessary to increase the supply of elemental fluorine in excess of 30% up to 50% of the required stoichiometry. The release of uranium hexafluoride per cycle in all modes reaches 99.9% of
Further processing of the received hexafluoride were performed as in example 1.P R I m e R 4. Processing details of the items are weapons based alloy of highly enriched uranium in oxidation, fluorination and purification were conducted as in example 3.The operation of mixing and the concentration of flows was calculated by the following dependency:
G1C1+ G2C2G3C3< / BR>G1+ G2G3where G1the flow of uranium hexafluoride with a high degree of concentration, g/s;
C1the concentration of uranium-235 in the uranium hexafluoride with a high degree of enrichment,
G2races uranium low enriched,
G3the flow of uranium hexafluoride, obtained after mixing, g/s;
WITH3the concentration of uranium hexafluoride, obtained after mixing,
Setting the necessary concentration in the finished uranium hexafluoride and quantity of the finished product, selected concentration and flow of the original flows hexafloride uranium.All technological scheme of processing of weapons-grade uranium supplied by instruments of analysis of gas streams before filing them in the cleaning stage, after cleaning in the cleaning stage prior to submission to the device of mixing and after mixing. In the cleaning stage and the mixing apparatus is a pressure control gas flows. To avoid increasing the concentration of uranium-235 for the limits on the gas flow provided by the emergency protection and lock that automatically prevent admission of gaseous products.The invention can be applied to manufacturing of hexafloride uranium with varying degrees of enrichment of uranium-235 in relation to fuel nuclear reactors as energy and transport for submarines and space. 1. METHOD for PROCESSING WEAPONS-grade highly ENRICHED URANIUM AND who uranium, the fluorination of uranium oxides, purification of uranium hexafluoride from impurities and obtaining fuel for nuclear reactors with a mixture of hexafloride different degrees of enrichment with subsequent filling of the fuel material in the container, characterized in that the oxidation of uranium metal carry oxygen at a temperature of 700 - 1100oWith, followed by fluorination of the resulting oxides of uranium elemental fluorine in excess of fluoride greater than stoichiometric to 5 - 50%, then the enriched uranium hexafluoride purified by the method of centrifugal separation, followed by mixing it with uranium hexafluoride containing uranium-235 below content in the fuel material, by continuously combining the two gas streams, and the resulting fuel material before filling Desublimers.2. The method according to p. 1, characterized in that the oxides of uranium foryouth at a temperature of 300 - 400oWith under stirring and the excess of fluoride greater than stoichiometric by 5 - 10%.3. The method according to p. 1, characterized in that the oxides of uranium foryouth at a temperature of 1400 - 1500oWith in excess of fluoride greater than stoichiometric by 10 - 50% with the introduction of the oxides in the reaction zone at gaseousness method of centrifugal separation cascade of gas centrifuges to impurity content of 10-4- 10-5wt.%.5. The method according to p. 1, characterized in that the mixing of the two gas streams is carried out by regulating the expenditure of each stream in accordance with the content of uranium-235.
FIELD: recovery of spent nuclear fuel.
SUBSTANCE: proposed method involves enhancement of uranium-235 isotope content in recovered uranium to 2.0-5.0 mass percent while reducing absolute and/or relative concentration of uranium even isotopes. Method includes division of isotope mixture of raw uranium reagent in gas-centrifuge isotope-division cascade and mixing of separated commercial isotope mixture with uranium thinner. Isotope mixture division is effected in two-cascade arrangement. Raw uranium reagent is enriched with uranium-235 fissionable isotope in first single cascade up to content over 90 mass percent. Second single cascade is used for cleaning isotope mixture from uranium-232 and uranium-234 isotopes. Select flow of second cascade enriched with uranium-235 isotope is conveyed as commercial isotope mixture for mixing up with uranium-thinner.
EFFECT: enhanced quality of reducing recovered uranium and minimized uranium-thinner requirement.
12 cl, 1 dwg, 6 tbl
FIELD: extraction processes for recovery of nuclear fuel, uranium concentrates, and uranium-containing reusable parts.
SUBSTANCE: proposed process for uranium extraction affinage includes dissolution of uranium concentrate at nitric acid excess of 0.75 - 1.0 mole/l and temperature of 80 - 95 °C; prior to extraction uranyl nitrate solution is doped with urea nitrate; post-extraction raffinate and alkali decanting product produced as result of re-extract treatment are separately subjected to carbamide denitration with solution being cooled down and urea nitrate sediment separated; decanting products produced in the process are mixed up and subjected to electrochemical treatment.
EFFECT: reduced nitric acid consumption and escape of raffinate-containing nitrate ions, escape of nitric oxides in uranium concentrate dissolution, and uranium loss with effluents.
7 cl, 5 dwg
FIELD: recovery of irradiated nuclear fuel.
SUBSTANCE: proposed method for reconditioning reusable extractant includes treatment of the latter with aqueous alkali solution. Extractant containing uranium in amount of minimum 5 g/l is treated with alkali solution whose concentration is over 10 mole/l followed by sediment separation.
EFFECT: reduced radionuclide content of reusable extractant including difficult-to-remove radioactive ruthenium.
5 cl, 2 tbl, 2 ex
FIELD: recovering solid irradiated nuclear fuels.
SUBSTANCE: proposed method for recovering solid irradiated nuclear fuel in the form of various uranium-containing composites (metal, carbide, oxide, and the like) for its further reuse in nuclear-fuel cycle includes dispersion of mentioned composites by way of thermal oxidation followed by vacuum baking at the same time distilling in vacuum volatile products of fission, such as cesium-137. Dispersion is conducted in controlled oxygen-containing medium while cycling them at temperatures ranging between 400 and 1000 °C; baking is conducted for 1 h at residual pressure of maximum 10-2 Pa and temperature of minimum 1300 °C.
EFFECT: ability of reducing gamma-activity of irradiated nuclear fuel, mainly cesium, to desired level for its reuse in nuclear fuel cycle.
5 cl, 1 tbl, 3 ex
FIELD: recycling technology for power-generating nuclear materials.
SUBSTANCE: concentration of uranium-235 fissionable isotope is raised above source content to desired value of 2-5 mass percent by direct enrichment in cascade of gas centrifuges. Uranium-235 concentration in cascade dump is 0.1-0.3 mass percent. At the same time uranium isotope mixture having lower concentration of uranium-232 and uranium-236 isotopes than burnt-up source mixture is thinned with hexafluoride. To this end uranium-thinner hexafluoride is introduced to interstage stream of cascade at same or almost same concentration of uranium-235 fissionable isotope. For thinning use is made of hexafluoride of natural mixture of uranium isotope, hexafluoride of uranium isotope mixture separated from burnt-up nuclear fuel, as well as mixture of source uranium isotope burnt-up mixture and hexafluoride of natural mixture of uranium isotopes or hexafluoride of uranium isotope mixture separated from burnt-up nuclear fuel.
EFFECT: ability of producing marketable uranium hexafluoride at minimal quantity of uranium-separating factory facilities used for thinner production.
16 cl, 3 dwg, 3 tbl
SUBSTANCE: invention relates to the technology of recycling nuclear energy material. The said method of isotopic recycling uranium involves correction of the composition of burnt uranium isotopic mixtures in a double centrifugal cascade with selection of hexafluoride of uranium isotopic mixtures, purified from dangerous radioactive isotopes U-232 and U-234, through selection of the heavy fraction of second ordinary cascade. Separation of uranium isotopic mixtures in the second ordinary cascade is done in the presence of a carrier gas. The carrier gas has average molecular weight ranging from 346 to 348 amu.
EFFECT: invention reduces the mass of dangerous radioactive wastes and reduces loss of fissile U-235 isotope.
7 cl, 1 dwg, 2 tbl
FIELD: nuclear physics.
SUBSTANCE: invention relates to a nuclear fuel cycle, and specifically to methods of treating contaminated hazardous 232U, 234U, 236U isotopes of uranium material on a gas centrifuge cascade. The method involves treating contaminated uranium material fed into a gas centrifuge cascade, obtaining low enriched uranium from cascade selection using natural uranium hexafluoride in an intermediate cascade selection into which natural uranium hexafluoride is fed, producing a product with low concentration of at least one of the hazardous 232U, 234U, 236U isotopes compared to contaminated material with mass ratio of contaminated uranium material to natural uranium hexafluoride taken for treatment equal to (1÷25):100.
EFFECT: treating uranium material contaminated with hazardous impurities, obtaining quality material with permissible content of limiting hazardous isotopes, widening of the raw material base for fission plants, less separation work for processing material.
7 cl, 4 dwg, 7 ex
FIELD: power industry.
SUBSTANCE: separation of uranium isotopes in the form of hexafluoride of isotopic mixture of uranic regenerate on the installation consisting of two subsequent gas centrifugal stages; at that, hexafluoride of uranium recovered as per isotopic composition is obtained in flow of the second stage bleeding powered with heavy fraction of the first stage, which has been obtained during enrichment of light fraction of the first stage with 235U isotope to the concentration not exceeding 20 wt %. Isotopes are separated at the first stage so that there obtained is concentration of isotopes 232U and 234U in heavy fraction of the first stage, which provide required concentrations 232U and 234U at the second stage bleeding, and isotopes are separated at the second stage till the second stage bleeding flow is saturated with isotope 235U, which ensures the required concentration of isotope 236U in the second stage bleeding flow.
EFFECT: eliminating hazardous high concentrations of fissionable isotope 235U.
FIELD: power industry.
SUBSTANCE: method and device are implemented when quasineutral axial symmetric multiple-component flow of plasma is obtained by means of plasma accelerator, during transportation of flow through azimuth device with transverse radial magnetic field, flow of plasma flow divided into masses through separating volume with stationary radial electric and homogeneous longitudinal constant magnetic fields, collection of ions of two groups of spent nuclear fuel (SNF) to ion receivers located on cylindrical surfaces. Ions of the third group of SNF are collected to annular end receiver.
EFFECT: group of inventions allows enlarging functional capabilities of plasma optic mass-separator owing to minimising negative impact of power and angular spreads of ions of various chemical elements in plasma flow and proper selection of the shape, quantity and location of receivers of groups of ions.
2 cl, 7 dwg
SUBSTANCE: mass separation of a multicomponent plasma stream is carried out using crossed radial electric and azimuthal magnetic fields as the plasma stream moves through a separating volume. The value of the azimuthal magnetic field is selected such that it ensures magnetisation of ions and electric drift of the plasma. The magnetic field generating system does not have an azimuthator. The combination of electromagnetic fields of the mass-separator ensures maximum dispersion at the focal point of central mass ions. The accompanying electron gun is linear, which ensures injection of electrons along the azimuthal magnetic field.
EFFECT: broader functional capabilities of mass-separators and simple design thereof.
FIELD: nuclear engineering.
SUBSTANCE: proposed method for volume crystallization of plutonium dioxide includes treatment of molten alkali-metal chlorides with plutonium compound dissolved therein, as well as treatment of melt obtained in the process by oxygen-containing gas mixture and precipitation of large-crystal plutonium dioxide on bath bottom. In the process closed-porosity graphite granules are disposed on melt surface, their contact with melt being afforded as they are consumed. Apparatus for volume crystallization of plutonium dioxide from molten alkali-metal chlorides with plutonium compound dissolved therein has bath, cover, melt mixing system, and device for feeding soluble plutonium compounds and gas mixture to melt. Bath, parts and assemblies contacting the melt are made of ceramic material shielded at melt boundary level with pyrographite parts. Gas mixture feeding devices have ceramic and pyrographite tubes.
EFFECT: enhanced durability of equipment.
3 cl, 4 dwg
SUBSTANCE: group of inventions concerns application of polymer-containing solution or water suspension paste and a device of ruthenium collection in gaseous discharge. The solution or water suspension paste contains one alkylene glycol polymer and/or one alkylene glycol co-polymer. The alkylene(s) contains 2-6 carbon atoms for ruthenium collection in gaseous discharge. The device includes a ruthenium collection cartridge with a substrate bearing alkylene glycol polymer or co-polymer. The alkylene(s) contains 2-6 carbon atoms.
EFFECT: improved ruthenium collection and chemical recovery of ruthenium oxide.
22 cl, 8 dwg
FIELD: fuel systems.
SUBSTANCE: invention is related to recycling of return nuclear fuel (RNF) and materials of blanket region (BR) of fast breeder reactors (FBR) for their multiple use with the possibility to adjust content in creation of a new fuel composition. Initial chemical state of processed material may vary: oxides, nitrides, metals and alloys. Method represents a combination of serial processes of chemical transformation of radiated nuclear fuel (RNF): fluoridation with gaseous fluorine and extraction of main uranium mass; transition of fluoridation remains into oxides (pyrohydrolysis); - chlorination of oxides in recovery conditions with group separation of plutonium chlorides, uranium (left in process of fluoridation) and fission products. Further "plutonium" and "uranium" fraction, and also fraction containing fission products (and, possibly, minor-actinides), are used each separately in various processes according to available methods. Earlier produced uranium hexafluoride, with low boiling fluorides of fission products, is cleaned from the latter and used, according to objectives of processing, also by available methods. Using waterless processes with application of salt melts, suggested version makes it possible to realise continuous highly efficient processes of fuel components production, moreover, it is stipulated to carry out preparation stages in continuous mode. Plant for processing of spent nuclear fuel containing uranium and plutonium includes three serially installed devices: fluoridiser; pyrohydrolysis device; chlorinator-condensator-granulator device. Two last devices are of flame type. The last of devices represents a pipe with a central element, in which lines of inlet product and reagents supply are installed. In lower part there is an expansion in the form of pear with a flame burner along its axis, and medium part has a row of conical shelves inside, between which there are nozzles with pipelines for chlorides outlet. Nozzle for chlorides outlet is also arranged in lower point of pear-like part. Nozzle for exhaust of non-condensed gases is provided in upper part. Granulator is arranged as reservoir with low boiling incombustible liquid, and to produce drops, capillaries are provided at pipeline ends.
EFFECT: highly efficient method for processing of spent nuclear fuel of practically any composition from thermal reactors and fast breeder reactors, blanket region of fast breeder reactors and some other types of reactors with the possibility to produce several other types of fuel compositions.
19 cl, 3 dwg
SUBSTANCE: proposed method comprises immersion of alloy into salt melt to change rare-earth element from liquid alloy into melt by oxidation. Note here that said oxidation us performed in zinc chloride melt at 420-550°C while melt zinc ions are used as oxidiser.
EFFECT: higher yield.
2 tbl, 2 ex
FIELD: technological processes.
SUBSTANCE: invention relates to a method and a device for bringing two immiscible fluids into contact. Method of binging into contact without mixing of the first substance consisting of metal or alloy of metals in liquid state and the second substance consisting of salt or salt mixture in liquid state, in which: the first substance in solid state is placed in the first container, the first container is put into contact with the second substance in solid state placed in the second container, the first and the second containers are exposed to electromagnetic field effect, the first substance in liquid state is brought into motion, the second substance in solid state starts melting under the effect of heat flow from the first container, the second substance in liquid state is brought into motion, the first substance in liquid state stays in contact with the second substance in liquid state for a certain period of time, the first container is removed from the second substance in liquid state, the first container is cooled until the first substance returns into solid state.
EFFECT: improved mass transfer kinetics.
35 cl, 10 dwg, 2 tbl
SUBSTANCE: invention relates to a method of producing oxychloride and/or oxide of actinide(s), and/or lanthanide(s) from chloride of actinide(s), and/or lanthanide(s), present in a medium containing at least one molten salt of chloride type. Method involves a step for reacting chloride of actinide(s) and/or lanthanide(s) with wet inert gas.
EFFECT: invention provides efficient production of oxyhalogenide and/or oxide of actinide(s), and/or lanthanide(s), as well as formation with elements of actinides or lanthanides, products, different from oxyhalogenides or oxides, and excluding cation-contamination of medium containing molten salt, simplifying recirculation of molten salts.
11 cl, 3 ex