The method of processing a metal alloy based on uranium
(57) Abstract:The invention relates to a method for processing a metal alloy based on UPRONA, mainly coroborating U235and other metal components, including the fluorination and subsequent distillation of the mixture of the fluorides of obtaining pure uranium hexafluoride and separating it from impurities. Essence: fluoridation are fluorine-containing gas to obtain a gaseous mixture of fluorides containing fluorides of uranium and others, including oxychoride metals, as obtained after distillation of pure hexafluoride coroborating uranium in liquid or gaseous state is mixed with hexafluoride less enriched uranium in the proportions necessary to obtain hexafluoride with a given isotopic content, the fluorination can be performed in 2 stages: in the first the other compounds, for example gaseous HF and UF6pick UF4in solid form, the second gas on the basis of fluorine. 11 C.p. f-crystals, 2 Il. The invention relates to the processing of metal-based alloy coroborating uranium to extract uranium in the form of pure uranium compounds with more natally metal alloy based on uranium, coroborating U235and usually containing a significant percentage ligious type elements Mo, Nb, Fe, Cr, Nr, Gr, Al, Zr, Ta, W, etc. Under coroborate understand the relations (U235/ all the number of U), usually exceeding 8%, but which may reach and even exceed 90%. We can talk about the alloys U-Sr, coming from a research reactor type materials, enriched by more than 20%, the alloys U-Al alloys for military purposes, etc., These alloys can be irradiated (e.g., waste, discarded alloys and so on) or irradiated.Of interest is an opportunity to unlock the potential number of U235contained in the provisions for use, for example, less enriched and purified form as fuel in a powerful nuclear reactors such as PWR, BWR or in reactors used for research.For this was found in the processing of these metal alloys, which allows to obtain pure uranium connection with homogeneous isotopic content of U235adapted for new use, non-use of the original product, and the chemical composition of such quality that would ispol for these purposes. This chemical compound must have, in particular, high purity and homogeneity.The invention relates to a method for processing a metal alloy based on uranium, mainly coroborating U235and other metal components, including the fluorination and subsequent distillation of the mixture of the fluorides of obtaining pure uranium hexafluoride and separating it from impurities, characterized in that the fluoridation are fluorine-containing gas to obtain a gaseous mixture of fluorides containing fluorides of uranium and others, including oxychoride metals, as obtained after distillation of pure hexafluoride coroborating uranium in liquid or gaseous state is mixed with hexafluoride less enriched uranium in the proportions necessary to obtain hexafluoride with a given isotope content.Usually metal original alloy contains large quantities ligerie elements such as Mo, Nb, Fe, Cr, Nr, Sl, Al, Zr, Ta, W, and even Pu, etc. It fluorination is carried out in the total mass or separately, this separation can be made from ingots or massive pieces by any means known to the expert in this field, for example, the tion to the management of a critical situation.The fluorination can be carried out in one or two stages:
in one step with gaseous fluorine. The exothermic reaction is controlled by introduction of an inert, normally non-condensable gas for dilution (for example, nitrogen, argon, and so on). On the one hand, receive a gaseous mixture containing non-condensable gases (mainly inert dilution gas), gaseous fluorides, and in some cases oxychoride (coroborating uranium and alloying elements that form volatile fluorides at the reaction temperature of the fluorination), and on the other hand, a solid residue consisting of impurities in the form of unburned substances and non-volatile fluorides, which is processed before it can be deleted;
two stage during the first stage of uranium turns into UF4and part of the metallic elements of the original alloy in fluoride using non-polluting gas fluoride, and during the second phase, when in addition to the fluoridation of the solid substance obtained in the first stage, processing is carried out using gas-based fluoride in similar terms fluoridation in one step.Fluoridation in two stages can be carried out according to two of poplava with anhydrous hydrofluoric gaseous acid to achieve the volatile fluorides, which must be removed after the separation (e.g. filtration), condensation and/or treatment for neutralization, as well as a solid residue, consisting mainly of solid fluorides (all uranium which is in the form UF4), and the second stage, during which all the solid residue is treated with gaseous fluorine under conditions similar to the conditions of fluorination in one step as already described.- according to the second method of performing the first stage is carried out by introducing a contact of the original uranium alloy with fluorine-containing gas-based UF6in which usually reduced the content of U235to turn just U or partially in UF4and fluoridation at least partial other metal components of the original alloy. During the second phase, the previously obtained solid substance is introduced into contact with fluorine, diluted if necessary with an inert gas to obtain, as has been described for the case of fluorination carried out in one step, on the one hand, a mixture of gaseous fluoride and non-condensable gas, on the other hand, unburned sediment and non-volatile products.U turns according sleduya substance) + F2(gaseous _ _ 3UF6/gaseous).According to the second method, the processing can be carried out in a countercurrent. Thus, in one end of the reactor is introduced metal alloy, preferably crushed in pieces, in the intermediate section of the reactor is injected gaseous, more depleted UF6and at the other end of the injected gas on the basis of fluorine. The mixture of gaseous fluorides and non-condensable gas is output from the end, in which is inserted a metal alloy.The second method is characterized by several advantages:
due to the fact that the fluorination is performed in two cycles with intermediate receiving UF4using entered in connection fluoride (UF6), the temperature control of the reaction is greatly facilitated and improved. A similar advantage is also achieved in the first method, when using HF;
due to the fact that exercise at this stage of the process of isotope mixing, designed to reduce the isotopic content of U, this is an opportunity to limit problems critical situation in the implementation process, and, consequently, a significant simplification of the issues related to the development of the dimensions and rules, ndesired for so you can take usually in the liquid state and stored in an intermediate tank, which is usually supported liquid state. When such condensation of non-condensable gases are separated.The condensation can be carried out with cooling in one or more consecutive the mold under pressure at a temperature of approximately -25oC in order to remove any small amount of fluoride U in non-condensable gases. These gases consist mainly of a mixture of excessive fluoride, dilution gas (nitrogen, argon, and so on), or non-condensable fluoride (SiF4). They can be removed in the waste after they will be skipped, if necessary, through the treatment column and/or the security filter, but they can also be made available again on the stage fluorination provided that they do not contain non-condensable gaseous fluorides, allowing you to use less crystallization and processing of the above gases.Purification of the mixture of fluoride stored in an intermediate tank, is carried out in one or more distillation consecutive columns depending on the complexity of the mixture subjected obrabotke reflux, located in the upper part of the column and the reboiler located at the bottom of the column, the mixture of fluorides received for processing, usually introduced in a liquid state at an intermediate level.For example, a single column is sufficient for binary mixtures UF6and other fluoride impurities. In this case, by adjusting the ratio of reflux distilled condenser (refrigerator) and the degree of boiling, you can get pure UF6either at the top or bottom of the column depending on what other fluoride respectively less volatile (more severe) or more volatile (lighter) than UF6.On the contrary, in the case of complex mixtures containing in addition UF6a complex mixture of fluorides of volatile impurities, it is advantageous to use several consecutive columns. In the first column is extracted, for example, the entire UF6in the upper part of the column where it is mixed with other fluorides, which are easier than he, while UF6is separated from the heavier fluoride than he, and that extracted from the bottom of the column.In the second column enter this mixture UF6with light fluorides and extract pure UF6from the base of the column, removing boat be performed in reverse order.In order to achieve the desired purity of each column is governed by the ratio of reflux distilled capacitor and the degree of boiling. However, it is clear that it is possible to use additional columns for the separation of metal fluorides from each other, which may be of interest.After the operation of the distillation separately pure UF6and various other fluorides in the liquid state. At the top of the capacitors are also separated and extracted gases which do not condense at the temperatures of the upper parts of the columns in small quantities, which are mainly emitted after the treatment, but which can be used for recycling, if the composition is suitable for this.Other above-mentioned fluorides (except UF6) after hardening can be stored in this form, but it is preferable to process. Usually, they are subjected to hydrolysis to obtain, on the one hand, HF, which can be used, and, on the other hand, metals initial uranium alloy in the form of oxides, which are convenient to store, carry and use. The above oxide can then be restored by hydrogen, if you want to get on. It can be mixed in this state or in the state of gas dosed flow, net UF6(usually with reduced U235in a gaseous or liquid state, metered flow depends on the respective values of U235in the mix UF6and from the content that you want to receive.More depleted UF6can be obtained advantageously based vergoeding uranium (0,2% U235), which is present in large quantities or on the basis of depleted U or natural uranium.The mixture obtained from UF6in the liquid or gaseous state, is characterized by the advantage of simplicity and the possibility of obtaining UF6with excellent uniformity of the isotopic and chemical.After mixing, the resulting net UF6with the necessary isotopic content is condensed, is poured into the container for transport, storage or use as is usually done.Alternatively, before step fluorination can be accomplished stage oxidation of the alloy in a furnace using gas based on the oxygen, diluted if necessary to slow down the reaction. This operation is Vigo non-volatile oxides during the operation and are condensed separately. Thus, carry out a preliminary treatment, which facilitates and makes it much easier to follow, already described operation of intensive purification by fractional distillation. This phase oxidation is of particular interest in the case, when the original alloy contains Mo, or a metal of the same species.Solid extracted thus the oxides, of which separates U3O8, are then processed at the stage of fluorination, forming, as described above, volatile fluorides, in some cases, oxychoride, and non-condensable gases (oxygen comes from the oxides and unburned solid precipitation.In Fig. 1 illustrates the various stages of the process with the basic options, where 1 is the alloy in the form of unit; 11 - trimmed alloy; 12 - option pre-oxidation of the alloy in the form of a block or in a fragmented form with oxygen 13, more or less diluted, probable, volatile oxides 14; 2 fluoridation alloy in the form of a block or in a fragmented form or oxide using a gas 20 containing fluorine and usually inert non-condensable gases, as mentioned above, this fluorination can be carried out in two stages with intermediate UF4the house noncondensable gases 22, if necessary, at least in part are recirculated 20 and/or processed in 24, for example, filtration and/or washing before removing 25; 23 - heating of condensed fluorides 20; 3 - fractional distillation in order to purify UF6implemented in one or more columns; 31 exit probable non-condensable gases, if they were not previously separated, which can be used as before recycled 20 and/or processed in 24 before removing 25; 32 - numerous selection of various fluorides alloying elements other than uranium, they can be processed in 33 usually by hydrolysis to obtain elements in the form of oxide 34 and hydrofluoric acid in 36, then the recovered hydrogen 341 for receiving the metal alloy 342; 36 output net UF6usually in liquid form; 37 - heating UF6to bring it to a gaseous state; 4 - the operation of mixing pure UF in the liquid or gaseous state with a more depleted UF6in the liquid or gaseous state in dosed quantities; 41 - condensation and fill in the container ready UF6isotopic content.In Fig. 2 shows the fractional distillation (position 3 in Fig. 1), consisting the of retene, the following examples were carried out in natural alloys in examples 1 and 2 (but these latter are transported in the same terms as enriched U), and in the case of example 3 was used alloy coroborating uranium.Example 1. As the original product used set pieces alloys, analysis of which showed the following composition: 5% Nb, 5% Mo, 1% Ti, 1% Fe, 0.1% of Ni, the solid consists of natural uranium contains 0.7% of U235. The product was subjected to grinding so as to provide particle size in the range from 1.5 to 25 mmThe product was subjected to continuous fluorination reactor from Manila with an outer diameter of 88.9 mm, thickness of 3.05 mm, which is equipped with a cooling system, a thermostatic environment. Consumption of fluoride was 455 g/h under an absolute pressure of 1.2 bar with the temporary addition of N2to maintain the temperature of the walls of the reactor equal to 320 30oC. In these cases, the nitrogen flow was varied from 0 to 100%, basically he was 40 and 70% of total consumption.The resulting gaseous fluorides fully assembled in the mold under an absolute pressure of 0.5 to 0.1 bar, cooled to -25oC freon 113 to obtain Christmas KOH solution.The mixture zakristallizuetsya fluoride contains all of the amount of uranium, molybdenum and niobium, respectively, in the form UF6MoF6, NbF5and traces TiF4.In the lower part of the reactor for fluorination was collected in the form of fluorides all amounts of iron and Nickel.The material balance revealed the following outputs: U extracted in the form of zakristallizuetsya UF6/U original alloy, equal to almost 100%; fluorine contained in the solid or zakristallizuetsya the fluoride/fluorine, which came in response equal to 95%.After intermediate storage in a buffer tank zakristallizuetsya fluorides melted to ensure their continuous introduction into the distillation cycle, consisting of two consecutive columns.They were introduced under an absolute pressure equal to 3.3 bar, in the lower third of the column with a nozzle of Manila (diameter 55 mm, height 1200 mm) at a constant flow rate equal 4,977 kg/h or 1.3 l/h for the average composition 51: 4,333 kg/h UF6, 0,352 kg/h MoF6, 0,325 kg/h NBF5traces TiF4.Thermal equilibrium was maintained at 92oC in the middle of the column 52 for consumption phlegmy 53, which was 8 l/h and flow rate selection in S="ptx2">In the upper part of the column was collected following a mixture of 55 under pressure of 3.2 bar: UF6- 4,077 kg/h, MoF6- 0,352 kg/h, and in the lower part of the column was obtained a mixture containing: NbF5- 0,325 kg/h UF6- 0,223 kg/h, TiF4- traces.The mixture from the upper part 55, which can be re-processed in a loop through distillation, adapted to extract Nb and U, was introduced in the lower third of the 56 second column of the same type (diameter 40 mm, height 2400 mm) under a pressure of 3.2 absolute bar 87oC.Spending phlegmy and expenses of selection was equal to, respectively: phlegm from 57 to 34 l/h; the selection of the lower part 53 + 1,14 l/h or UF6- 4,069 kg/h; the selection of the capacitor upper part 59 - 0,12 l/h or MoF6- 0,3532 kg/h UF6- 0,002 kg/hUF6coming from the bottom, gathered in a container with a capacity of 25 kg Averaged data analysis (wt. %), referenced to uranium, the following: Mo < 110-4, Nb < 110-4, Fe < 0,5110-4Ti < 0,5110-4.These 25 kg, is in a liquid state at a temperature of 75oC, was added 6.25 kg net UF6containing 0.25% U235pre-heated in the vessel is also up to 75%. The resulting capacity of the weighing of 31.25 kg, has an isotopic content of 0.61% and two stages using a fluorine-containing compounds (UF6) original alloy U-type3Si2.Original alloy U3Si2comes in powder form with particle size less than 150 microns and with the following chemical composition, wt.%: U Of 92.6%, Si Of 7.3%, Al Of 10.1%.This powder is a product which is derived from a fuel used in studies based on U3Si2and enclosed in a matrix of Al, with the matrix previously removed by alkaline etching or by using any other method.As in the previous example, the work was carried out for practical purposes with natural URANIUM (0.7% of U235).The work was carried out in a flotation reactor, identical to the reactor used in example 1, however, taking into account the ground state of powder, was used supply system of the above powder, protected by purging with argon.The introduction of components was as follows: in the upper part of the reactor 770 g/h powdered alloy; in the middle part of the reactor 2112 g/h vergoeding UF6(0,3% U235); in the lower part of the reactor 516 g/h of fluorine, the content of HF in which less 10010-4more or less diluted with Ar to counter the m of example 1.From the top of the reactor was recovered gaseous mixture containing: 22 g/h of fluorine and dilution of its argon; 3168 g/h UF6isotopic content of U235which was 0,43%; 208 g/h SiF4.Also removed unburned solids consisting of AlF3.The gaseous stream is cooled to -25oC and, thus, are condensed the whole mass UF6and receive vent gases containing excess fluoride and all the number of SiF4(208 g/h).The simple removal of the gas from secretarytreasurer UF6under reduced pressure and maintaining the temperature at a set level is allowed to get then UF6containing less than 110-4Si and less than 2010-4The HF.Example 3. As the original product used set pieces alloy irradiated fuel type U3Si2based sredneoblastnogo uranium (20% U235) contained in the aluminum matrix.The composition of the product was substantially as follows, wt.%:
Uranium - 80%
Si - 3%
Product division (PF PD) - 7%
Aluminum - 10%
The most important fission products are Pu, Mo, Nb, Ti, Ru, Mg.First, the products are subjected to continuous is g/h, which is diluted continuously fed 500 g/h H2. The temperature was maintained at 400oC and pressure of the reactor was 102kPa.Received volatile fluorides were subjected to filtration. As for the non-volatile fluorides UF4that remained in the reactor, they were then subjected to continuous fluorination at 350oC under a pressure of 102kPa. Consumption of fluoride was equal to 150 g/h, which was diluted in N2with a flow rate of 500 g/hVolatile fluorides were subjected to filtering in the column with metal nozzle, which allowed to remove non-volatile fluorides, and Pu in the form of rigid PuF4received by the decomposition of gaseous volatile PuF6. Then they were cooled in the condenser, in which the temperature was maintained equal to -20oC and in which UF6was kristalizovyvatsja. The pressure was equal to 102kPa.Non-condensable gases, mostly F2O2N2were filtered and processed by the absorber with lime.After vacuum degassing in saying a few hours a condenser was heated to 90oC and liquid UF6was subjected to two successive distillations.
6and in the second column extracted from the upper part of basically a few tens of grams MoF6and from the bottom of the net UF6.Activity UF6thus obtained was below 210-7Ci/gY , banal content of metallic impurities below, 5010-4of which Mo less than 110-4.Then this gaseous UF6? was introduced by bubbling (mixing) in the amount of 14.5% in the container of natural uranium to obtain UF6enriched to 3.5% U235completely homogeneous, intended to produce fuel according to a known method.The method according to the invention allows to obtain a clean finish homogeneous UF6in particular, regarding the content U235. It allows you to remove impurities contained in the initial alloy, and does not create any flowing stream that would need to be treated before its release. It also allows you to limit the question of a critical situation due to the absence of the aqueous phase. 1. The method of processing a metal alloy based on uranium, mainly coroborating U235and other metal components, including fluoridation and poseima, characterized in that the fluoridation are fluorine-containing gas to obtain a gaseous mixture of fluorides containing fluorides of uranium and others, including oxychoride metals, as obtained after distillation of pure hexafluoride coroborating uranium in liquid or gaseous state is mixed with hexafluoride less enriched uranium in the proportions necessary to obtain hexafluoride with a given isotope content.2. The method according to p. 1, characterized in that before fluoridation metal alloy is subjected to grinding.3. The method according to p. 1 or 2, characterized in that the metal alloy before fluoridation was processed gas based on the oxygen after likely necessary grinding for solid oxides, which separates U3O8and nitric oxide in a gaseous state.4. The method according to any of paragraphs.1-3, characterized in that before the distillation is conducted condensation of gaseous fluoride followed by the separation of non-condensable gases and transfer of fluoride in the liquid or gaseous state.5. The method according to any of paragraphs.1-4, characterized in that the fluoridation carried out in one step using gaseous fluorine, retlaw two stage, at the first stage, the alloy is treated with fluorine to obtain a solid substance containing uranium in the form UF4at the second stage, this solid is subjected to the processing gas on the basis of fluoride.7. The method according to p. 6, characterized in that the first phase of the alloy is treated with anhydrous gaseous hydrogen fluoride HF.8. The method according to p. 6, characterized in that in the first stage, the alloy is subjected to the processing of gaseous UF6preferably more depleted in U235than U of the original alloy.9. The method according to any of paragraphs.1-8, characterized in that the distillation is carried out in columns with the condenser and the boiler by the feed gas flow the top of one column to the bottom of another column or columns.10. The method according to any of paragraphs.1-9, characterized in that the condensation of non-condensable gases are separated from the condensed fluoride and recycle again on stage fluorination.11. The method according to any of paragraphs.1-10, characterized in that after distillation, the fluorides of other metals are separated from each other by distillation.12. The method according to any of paragraphs.1-10, characterized in that the fluoride other metallicum in metals.
FIELD: methods of unloading of uranium hexafluoride from steel containers and utilization of these containers.
SUBSTANCE: the invention is dealt with the methods of extraction of liquid and gaseous substances from steel containers and utilization of these containers. The invention allows extract uranium hexafluoride from steel containers of any volume filled in with uranium hexafluoride irrespective of the share of uranium isotope 235. The method provides for heating of the container in a closed space up to the temperature of uranium hexafluoride transition into a gaseous state. The process is conducted in a tight induction furnace with a metal segmented chilled crucible, a penetrable for an electromagnetic field metal transported chilled tray, a metal chilled inductor and a metal chilled body. The method is realized in two stages: heating of the container up to the temperature of 70-195°С and aging in the heated state under action of inductive currents at a frequency of 500-70000 Hz. The temperature of the crucible sections, the tray, the inductor and furnace body is kept in the limits of 70-195°С. Cooling of the crucible sections, the tray, the inductor and the furnace body is conducted with a high-boiling organic heat-transfer agent: diphenyl, orthoterphenyl and others.
EFFECT: the invention allows extract uranium hexafluoride from steel containers of any volume filled in with uranium hexafluoride irrespective of the share of uranium isotope 235.
4 cl, 2 ex
FIELD: industrial organic synthesis.
SUBSTANCE: method is accomplished by drying and then calcining uranium tetrafluoride in rotary tubular furnaces constituting assembled system provided with ventilation system, cooling screw, and container. Heat treatment of product is effected in air-completed own gas atmosphere, formation of atmosphere including calcination step gases. Air is preheated to 300-400°C and fed in countercurrent mode at a rate of 2-8 m3/h into calcination step and at 100-250 m3/h into drying step. Anhydrous product is cooled to 180°C or below and tightly sealed in container.
EFFECT: reduced power and materials consumption.
5 cl, 2 tbl
FIELD: industrial inorganic synthesis and radioactive materials technology.
SUBSTANCE: invention can be used for recovering uranium from exhausted nuclear fuel as well as from uranium production waste, uranium alloys, and products. Method involves dissolving uranium metal or alloy in nonaqueous solvent in presence of oxidant (in particular chlorine) and direct precipitation from nonaqueous solution. More specifically, dissolution is accomplished in tributyl phosphate/tetrachloroethylene system with 5 to 100 vol % tributyl phosphate and precipitation is caused by alkali metal or ammonium fluoride or hydrofluoric acid. Precipitated uranium fluoride is washed with heterogeneous tetrachloroethylene/water mixture.
EFFECT: accelerated dissolution of uranium-containing materials in absence of evolution of explosive gases and simplified process.
4 cl, 8 ex
FIELD: methods of reprocessing of uranium hexafluoride.
SUBSTANCE: the invention is pertaining to reprocessing of uranium hexafluoride and may be used for extraction of uranium hexafluoride from bottles of different volume. The method of transpiration of uranium hexafluoride from the bottles includes feeding of a carrier gas and a heating. As the carrier gas they use nitrogen, which is fed into the bottle at the pressure exceeding the pressure of gases inside the bottle by 15±5 kPa. Feeding of nitrogen is exercised in the pulse mode at the temperature of the bottle wall of 60-150°C and the pressure of the formed gas mixture of 50-150 kPa. The heating of the bottle with uranium hexafluoride is conducted with the help of a lateral two-section inductor. In the end of the process the bottle is vacuumized. Duration of a pulse of feeding of nitrogen makes 3-5 minutes, and the time interval duration between the pulses - 15-60 minutes. The pulsed feeding of nitrogen is conducted at the rate of nitrogen consumption of 2-6 kg/h. Vacuumization of the bottle is conducted up to the pressure of 50 kPa with simultaneous feeding of nitrogen during 10-15 minutes at the rate of consumption of 3-4 kg/h. The specific consumption of nitrogen makes 0.08-6.5·10-3 kg per 1 kg of uranium hexafluoride. The technical result of the invention is intensification of the uranium hexafluoride transpiration process, reduction of the mass of the product residue in the bottle, improved safety of the process.
EFFECT: the invention ensures intensification of the uranium hexafluoride transpiration process, reduction of the product residue mass in the bottle, improved safety of the process.
5 cl, 4 tbl, 1 ex
FIELD: inorganic synthesis.
SUBSTANCE: method consists in that uranium hexafluoride/hydrogen fluoride mixture is brought into contact with lithium fluoride at 30-60°C.
EFFECT: simplified isolation procedure.
1 dwg, 1 tbl
FIELD: nuclear fuel technology.
SUBSTANCE: invention relates to nuclear fuel cycle and can be used in manufacturing of nuclear reactor fuels by processing high-enrichment uranium removed from dismantled nuclear ammunition and having elevated content of minor uranium isotopes. Method of invention comprises conversion of high-enrichment arms uranium in its hexafluoride, which is then purified by removing chemical impurities in sorption-desorption cycle on metal fluorides. Isotope composition of high-enrichment uranium is adjusted on condition of restricting level of minor isotope in high-enrichment uranium by their limiting values on a rectangular-stepped cascade of gas centrifuges at ratio of numbers of steps in heavy and light fraction branches of the cascade 1:(8÷26). High-enrichment uranium hexafluoride is then mixed with diluting uranium hexafluoride enriched in uranium-235 isotope above its natural level, which was prepared from commercial natural material. Withdrawn light fraction of high-enrichment uranium cascade is diluted with refuse stream from uranium-diluent manufacture.
EFFECT: reduced irreversible loss of U-235, minimized separation means to manufacture high-enrichment uranium diluent, and reused isolated minor uranium isotopes.
4 cl, 1 dwg, 2 ex
FIELD: chemical industry; other industries; devices for concentrating of the impurities in uranium hexafluoride (UHF).
SUBSTANCE: the invention is pertaining to the field of analysis of the substances, in particular, to the methods of determination of the content of the impurities in the gaseous uranium hexafluoride. The device represents the cylinder (1) made out of the hard-drawn corrosion-proof pipe. On the both ends of the cylinder there are the flanges (2), (3) fixed through the pressure-seal gaskets by means of the bolt joints. In the lower flange (3) there is the hole, to which the body of the needle-shaped batching valve (4) is fixed. Using the needle-shaped batching valve (4) conduct the smooth inflow of the analyzable mixture into the source of the ions of the gaseous mass-spectrometer. In the upper flange(2) there is the mounted gland seal of the coupling rod (5) transferring the piston. The piston (6) consists of two detachable parts. On the lower part of the piston there is the mounted shim (7) made out of rubber and the Teflon (8). In the walls of the cylinder there are two nipples with the cap nuts, by means of which the device is connected to the system of the probe injection. The upper nipple (9) is intended for formation of the constant vacuum in the piston-behind volume. The lower nipple (10) is intended for the inflow and pumping out of the analyzable gaseous mixture in the volume of the device. The process of realization of the compression takes place due to the screw pair (11), which relocation is exercised by turning the handle (12). Relocating of the piston is exercised up to the lower flange (3). At that the theoretical factor of the gas compression is equal to the ratio of the volumes of cylinder V0 and volume of the hole in the lower flange Vl. For elimination of condensation of UHF on the internal walls of the cylinder and the unobstructed relocation of the piston outside on the cylinder the heating winding (13) is mounted. The technical result of the invention is development of the simple and reliable device disposed in the system of introduction of the probe of the gaseous mass-spectrometer and allowing effectively to concentrate the impurities in the uranium hexafluoride by precompression of the analyzable probe at the room temperature, the increased sensitivity of determination of the content of the impurities.
EFFECT: the invention ensures development of the simple and reliable device disposed in the system of introduction of the probe of the gaseous mass-spectrometer and allowing effectively to concentrate the impurities in the uranium hexafluoride by preliminary compression of the analyzable probe at the room temperature, the increased sensitivity of determination of the content of the impurities.
2 cl, 2 ex, 3tbl, 1 dwg
FIELD: atomic industry; chemical industry; devices for evaporation of the uranium hexafluoride from the solid phase into the gaseous phase.
SUBSTANCE: the invention is pertaining to the equipment for evaporation of the uranium hexafluoride from the solid phase into the gaseous phase, from the containers in the technological cascade for separation of the uranium isotopes, and may be used in the atomic industry. Installation works as follows. At the removed cover (2) and the tilt-back supports (20) the container (I) is installed by the crane into the body (1) on the supports (19) orienting the container on the guides (21). The supports (20) set into the working position and set on them the container (II). To the valves of the containers I and II connect the technological pipe ducts (12) and (13) connecting the containers with the technological cascade on separation of the uranium isotopes. The places of the joints check for leakage and open the valves of the containers. On the body (1) by crane set the cover (2). Switch on the electrical engine (8) of the blower (5) and the heater (3). The hot air heated by the heater (3) through the diffuser (9) is inhaled by the blower (5) and pumped into the cavity "A", whence through the air ducts is fed into the cavities "B" and "C". At the outlet of the air ducts formed by the removable partitions the hot air is routed by the deflectors (22) into the lower part of the container (I), and from the air ducts formed by the pockets of the lateral walls of the body, it is routed to the lower part of the container (II) and into the upper part of the container (I). The hot air is moving along the walls of the containers to the inlet of the blower (5) through the heater (3). This way the heating of the containers and the subsequent evaporation of the uranium hexafluoride from them into the technological cascade on uranium isotope separation is exercised. After termination of the process of evaporation of the uranium hexafluoride from the containers the heater (3) and the blower (5) are switched off. Open the small door (23) in the cover (2) and cool the containers, pumping the cold air through the small door (23) into the ventilation system. After cooling of the containers lift the cover (2) off, open the small door (11) and shut the valves of the containers, disconnect the pipe ducts (12) and (13) and pull the containers out. The technical result of the invention is the increased efficiency of the installation without occupation of the larger working areas.
EFFECT: the invention ensures the increased efficiency of the installation without occupation of the larger working areas.
FIELD: industrial inorganic synthesis.
SUBSTANCE: invention relates to technology of processing exhausted (wasted) uranium hexafluoride into uranium fluoride. Method envisages hydrolysis of solid uranium hexafluoride with aqueous hydrogen fluoride solution at 20-30°C and excessive pressure up to 100 kPa in closed space of rotating reactor.
EFFECT: completely eliminated uranium hexafluoride and hydrogen fluoride gas loss as well as environmental exposure to extremely volatile and dangerous substances.
FIELD: radioactive compounds technology.
SUBSTANCE: invention relates to technology of separation of uranium isotopes in gas centrifuges and can be used for cleaning and passivation of gas centrifuges as well as restoration of passability of routes of gas centrifuges operated in uranium hexafluoride medium. Method is implemented with gas centrifuge operated at nominal rotation speed. Fluorination compound in the form of iodine heptafluoride is added to centrifuge routes at its pressure from 60 to 7000 Pa in gas centrifuge routes. Discharge of JF7 and gasification products from gas centrifuge is effected through heavy fraction route to cold trap and through light fraction route to cryogenic trap. JF7 is returned from traps to gas centrifuge feeding route. Gasification control is based on gas centrifuge friction power variation. Method enables gasification nonvolatile compounds without visible traces of corrosive effects of fluorination compound on the parts of rotor group of gas centrifuge. Method further simplifies gasification of nonvolatile compounds and enables controlled restoration of passability of gas centrifuge routes. Before supplying uranium hexafluoride, working surfaces of gas centrifuges are cleaned and passivated.
EFFECT: simplified technology, achieved restoration of fluorination compound, minimized centrifugal equipment shutdown, tens times reduced restoration time of gas centrifuge route passability, and tens times reduced consumption of fluoro-oxidant.
9 cl, 4 dwg, 2 ex
FIELD: rare, dispersed and radioactive metal metallurgy, in particular hydrometallurgy.
SUBSTANCE: invention relates to method for reprocessing of polymetal, multicomponent, thorium-containing radwastes, formed when reprocessing of various mineral, containing rare-earth elements, Nb, Ta, To, V, Zr, Hf, W, U, etc. Method includes treatment of solution and/or slurry with alkaline agent; introducing of sulfate-containing inorganic compound solution and barium chloride; treatment of obtained hydrate-sulfate slurry with iron chloride-containing solution, and separation of radioactive precipitate from solution by filtration. As alkali agent magnesia milk containing 50-200 g/dm2 of MgO is used; treatment is carried out up to pH 8-10; sodium sulfate in amount of 6-9 g Na2SO4/dm2 is introduced as solution of sulfate-containing inorganic compound; barium chloride solution is introduced in slurry in amount of 1.5-3 g BaCl2/dm2. Hydrate-sulfate slurry is treated with solution and/or slurry containing 0.8-16 Fe3+/dm2 (as referred to startingsolution) of iron chloride, followed by treatment with high molecular flocculating agent and holding without agitation for 0.5-2 h. Radioactive precipitate is separated from mother liquor, washed with water in volume ratio of 0.5-2:1; then washed with sodium chloride-containing solution and/or slurry in volume ratio of 0.5-2:1; radioactive precipitate is removed from filter and mixed with mineral oxides in amount of 0.5-0.8 kg MgO to 1 kg of precipitate. Formed pasty composition is fed in forms and/or lingots and presses with simultaneous heating up to 80-1200C.
EFFECT: filtrate with reduced radioactivity due to increased codeposition coefficient of natural Th-232-group radioactive nuclide, in particular Ra-224 and Ra-228, with radioactive precipitates.
10 cl, 1 ex
FIELD: chemical technology; recovery of deactivated and decontaminated radioactive industrial wastes.
SUBSTANCE: proposed method that can be used for deactivating and decontaminating industrial radioactive wastes incorporating Tb-232 and their daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Sl, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like includes dissolution of wastes, treatment of solutions or pulps with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9 - 10 in the amount of 120-150% of total content of metal oxyhydrates stoichiometrically required for precipitation, pulp is filtered, and barium chloride in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp, as well as pre-diluted sulfuric acid spent 5 - 20 times in chlorine compressors in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2 are introduced in filtrate. Alternately introduced in sulfate pulp formed in the process are lime milk to pH = 11 - 12, then acid chloride wash effluents from equipment and industrial flats at pulp-to-effluents ratio of 1 : (2 - 3) to pH = 6.5 - 8.5, and pulp obtained is filtered. Decontaminated solution is discharged to sewerage system and sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization process; then 35 - 45 mass percent of inert filler, 10 - 20 mass percent of magnesium oxide, and 15 -m 25 mass percent of magnesium chloride are introduced in pasty mixture formed in the process while continuously stirring ingredients. Compound obtained is subjected to heat treatment at temperature of 80 - 120 oC and compressed by applying pressure of 60 to 80 at.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes due to enhanced coprecipitation of natural radionuclides.
7 c, 1 ex
FIELD: chemical technology; deactivation and decontamination of radioactive industrial products and/or wastes.
SUBSTANCE: proposed method designed for deactivation and decontamination of radioactive industrial products and/or production wastes incorporating Th-232 and its daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Al, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like and that ensures high degree of coprecipitation of natural radionuclides of filtrates, confining of radioactive metals, and their conversion to environmentally safe form (non-dusting water-insoluble solid state) includes dissolution of wastes, their treatment with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9-10 in the amount of 120-150% of that stoichiometrically required for precipitation of total content of metal oxyhydrate; then pulp is filtered and barium chloride is injected in filtrate in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp and pre-dissolved in sulfuric acid of chlorine compressors spent 5-20 times in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2. Then lime milk is added up to pH = 11 - 12 and acid chloride wash effluents of equipment and production floors are alternately introduced in sulfate pulp formed in the process at pulp-to-effluents ratio of 1 : (2-3) to pH = 6.5 - 8.5. Filtrate pulp produced in this way is filtered, decontaminated solution is discharged to sewerage system, sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization, inert filler and 0.5 - 2 parts by weight of calcium sulfate are introduced in pasty mixture while continuously stirring them. Compound obtained in the process is placed in molds, held therein at temperature of 20 - 50 oC for 12 - 36 h, and compacted in blocks whose surfaces are treated with water-repelling material.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes.
8 cl, 1 dwg, 1 ex
FIELD: uranium technologies.
SUBSTANCE: method comprises sorption of uranium on low-basicity anionites, desorption of uranium, and recovery of finished product. In particular, uranium-saturated low-basicity anionite is converted into OH- form and uranium into soluble stable complex [UO2(CO3)3]-4 by treating sorbents with alkali metal and ammonium carbonate solutions.
EFFECT: achieved complete desorption of uranium and simultaneously sorbent is freed from poisons and other sorption components.
SUBSTANCE: extractant has bi-phosphorus acid and additionally has tri-phosphate with relation of said components (0,5-1,25):1. Method for producing extractant includes adding to 2-ethylhexanole of chlorine oxide of phosphorus with their relation (4,5-5,1):2,0, and with parameters determined by reaching fullness of passing of reaction, after that reaction mixture is exposed until full removal of formed chlorine hydrogen, then to received mixture 1 mole of water is added, mixture is exposed to full hydrolysis. Then mixture is washed ad water layer is separated from organic remainder, containing said bi-phosphoric acid and tri-phosphate.
EFFECT: higher efficiency.
2 cl, 1 dwg, 2 tbl, 4 ex