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Mac L Toth - One of the best experts on this subject based on the ideXlab platform.
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matrix infrared spectra of hydrogen chloride complexes with Uranium Hexafluoride tungsten Hexafluoride and molybdenum Hexafluoride
Inorganic Chemistry, 1991Co-Authors: Rodney D Hunt, Lester Andrews, Mac L TothAbstract:HCl complexes with UF[sub 6], WF[sub 6], and MoF[sub 6] were prepared in solid argon at 12 K. The FTIR spectrum of UF[sub 6]/HCl contained a doublet at 2850.6 and 2849.7 cm[sup [minus]1] due to the hydrogen-bonded UF[sub 6]-HCl complex. In contrast, the HCl interaction with WF[sub 6], as well as MoF[sub 6] produced two distinctly different 1:1 complexes. The 2862.1-cm[sup [minus]1] absorption due to the antihydrogen-bonded complex, WF[sub 6]-ClH, was slightly more intense than the 2866.2 cm[sup [minus]1] absorption due to the antihydrogen-bonded complex, WF[sub 6]-ClH, was slightly more intense than the 2866.2-cm[sup [minus]1] absorption of the hydrogen-bonded complex, WF[sub 6]-HCl. The frequencies and relative intensities of the absorptions for the MoF[sub 6] complexes with HCl were very similar to those of their WF[sub 6] counterparts.
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infrared spectra of Uranium Hexafluoride tungsten Hexafluoride molybdenum Hexafluoride and sulfur Hexafluoride complexes with hydrogen fluoride in solid argon
The Journal of Physical Chemistry, 1991Co-Authors: R D Hunt, Lester Andrews, Mac L TothAbstract:UF{sub 6}, WF{sub 6}, MoF{sub 6}, and SF{sub 6} have been codeposited with hydrogen fluoride in excess argon at 12 K. The FTIR spectra of UF{sub 6} and HF revealed a strong UF{sub 6}-HF complex absorption at 3,848 cm{sup {minus}1} along with a weak, broad band at 3,903 cm{sup {minus}1} due to the UF{sub 6}-FH complex. Only one 1:2 complex with a UF{sub 6}-H{sub a}F-H{sub b}F arrangement was detected at higher HF concentrations and sample annealings. Similarly, the HF interaction with tungsten Hexafluoride formed two 1:1 complexes. However, the 3,884-cm{sup {minus}1} band due to the anti-hydrogen-bonded complex WF{sub 6}-FH was considerably stronger than the WF{sub 6}-FH{sub b}-FH{sub a} structure. The band positions and relative intensities for the MoF{sub 6} complexes with HF and DF were very comparable to their WF{sub 6} counterparts.
V A Palkin - One of the best experts on this subject based on the ideXlab platform.
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reprocessed Uranium Hexafluoride purification from 232 234 236 u in pentaflow gas centrifuge cascades
Atomic Energy, 2020Co-Authors: V A PalkinAbstract:A computational experiment was performed to purify reprocessed Uranium Hexafluoride from 232,234,236U in an additional product flow of cascades with a specified number of gas centrifuges in stages. The method used in the calculations takes into account the dependence of the separation coefficients of gas centrifuges on their feed flow and flow division factor. A cascade scheme for purification with simultaneous production of low-enrichment Uranium from natural Uranium in the main product is investigated. The cascade has to feed flows with regenerated natural-Uranium Hexafluoride, two product flows, and one waste flow. The cascade parameters that increase the purification efficiency are determined. It is shown that Uranium Hexafluoride in the products of the cascade satisfies the ASTM C996–15 international specifications established for low-enrichment commercial grading.
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purification of regenerated Uranium Hexafluoride by removal of 232 234 236 u in the intermediate product of a two feed flow cascade
Atomic Energy, 2019Co-Authors: V A Palkin, E V MaslyukovAbstract:The enrichment of regenerated Uranium Hexafluoride in a cascade with an intermediate product flow and additional feed flow of native or depleted Uranium Hexafluoride is studied. Low enrichment regenerated Uranium Hexafluoride to be used for the fabrication of nuclear fuel is produced in the main product flow; product with the same 235U concentration as in the main feed flow with regenerated Uranium Hexafluoride but significantly lower content of 232,234,236U is produced in the intermediate flow. To improve quality in terms of 236U, the point of entry of the additional feed flow of depleted Uranium Hexafluoride can be shifted closer to the main feed flow with a small increase of the total flow in the cascade. The separation work can be significantly reduced by introducing an additional intermediate product flow into the cascade.
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232 234 236 u removal from contaminated waste Uranium Hexafluoride in a double cascade
Atomic Energy, 2018Co-Authors: V A PalkinAbstract:Two schemes with double cascades are presented for purifying waste Uranium Hexafluoride with high 232,234,236U content. A large flow of native Uranium Hexafluoride and a low flow of waste Uranium Hexafluoride are fed into the first cascade. One of the external outgoing streams contains low-enrichment Uranium Hexafluoride with prescribed 235U concentration <5%. The 235U concentration of the second outgoing stream coincides with the feed concentration of waste Uranium Hexafluoride. 232,234,236U concentration reduction occurs in this stream, corresponding to purified waste Uranium Hexafluoride. The obtained products can be used effectively for enrichment in a cascade meeting ASTM C 996–15 specifications for low-enrichment commercial Uranium.
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purification of regenerated Uranium Hexafluoride by removal of 232 234 u in a centrifuge cascade with prescribed concentration of one of the isotopes 232 234 235 u
Atomic Energy, 2018Co-Authors: V A Palkin, E V MaslyukovAbstract:Schemes are proposed for purifying regenerated Uranium Hexafluoride by removal of 232,234U in an optimal centrifuge cascade with prescribed external concentration of one of the isotopes 232,234,235U. The cascade is optimized according to the criterion of minimum total number of centrifuges. The purification effect is achieved in the waste flow of the cascade when the feed point is shifted toward the product. The number of steps in the cascade is determined by a preliminary calculation of an R-cascade with different key components. The product parameters and the desirable number of the feed step are picked on the basis of the limit 235U concentration 5–20%. Calculations showing the possibility of cascades with different degrees of purification by removal of 232,234U were performed.
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purification of regenerated Uranium Hexafluoride in a two cascade scheme with 5 235 u enrichment
Atomic Energy, 2017Co-Authors: V A Palkin, E V MaslyukovAbstract:Two schemes are proposed for purifying regenerated Uranium Hexafluoride in double cascades. A large flow of native and a small flow of regenerated Uranium are fed into the first cascade. One of the external outgoing flows contains low-enrichment Uranium with prescribed concentration <5%. The concentration of the second outgoing 235U flow coincides with the regenerated Uranium feed concentration. In this flow, corresponding to purified regenerated Uranium Hexafluoride, the 232,234,236U concentration decreases. The obtained products meet the ASTM C 996–10 specifications for low-enrichment Uranium Hexafluoride.
V K Ezhov - One of the best experts on this subject based on the ideXlab platform.
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Hydraulic Resistance of Fine Packing in Uranium Hexafluoride Rectification
Atomic Energy, 2020Co-Authors: V K EzhovAbstract:The hydraulic resistance of irregular fi ne packing is studied as a function of the process parameters for the rectification of metal Hexafluorides. It is shown that the dependence of the hydraulic resistance of irregular fi ne packing on the rectification parameters coincides with the dependence presented in the literature but with different coefficients and exponential factors.
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Choice of Fine Packing for Rectification of Uranium Hexafluoride
Atomic Energy, 2017Co-Authors: V K EzhovAbstract:Coefficients are proposed for the Bain–Hougen equation for calculating the limit velocity of vapor in a column filled with fine packing for the rectification of metal Hexafluorides and their mixtures. It is shown that a simple method of comparing different packings in terms of the kinetic and hydrodynamic parameters is possible by using the effective throughput per unit volume of the packing, equivalent to one transfer unit.
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comparative method of calculating the thermodynamic parameters of some Uranium Hexafluoride solutions
Atomic Energy, 2016Co-Authors: V K EzhovAbstract:It is shown that the thermodynamics characteristics of Uranium hexafl uoride solutions with volatile hexaand pentafl uoride elements are a consequence of the strictly symmetric confi guration of their molecular structure in the gaseous and liquid states. Simple methods are proposed for evaluating the properties of binary mixtures of elemental penta- and hexafl uorides. These methods are based on a comparison of the element–fl uorine bond length in the constituent molecules of system and the known enthalpy of mixing of one solution with the potential energy in the formation of a pair of unlike molecules of a different solution. Researchers looking for a universal method of deep purifi cation of Uranium hexafl uoride have turned their attention to a rectifi cation method, for which there are no limitations on the depth of purifi cation, and a list of impurities to be removed, including metal impurities which are diffi cult to remove by means of water-extraction conversions of Uranium concentrates and give volatile fl uorides (molybdenum, tungsten, ruthenium, technetium, and others). Moreover, its specifi c productivity is high, the energy consumption is low, and the separation effi ciency is high. These advantages are due to the special properties of Uranium hexafl uoride as a working substance for rectifi cation: high density of liquid (more than 3.5 times higher than the density of water) and gaseous Uranium hexafl uoride, low viscosity comparable to that of water, good wettability of the metals which are corrosion resistant to fl uoride media, and low heat of evaporation of liquid Uranium hexafl uoride (less than 1/10th that of water). Deep purifi cation of Uranium hexafl uoride raw material by rectifi cation has been used in the Republic of South Africa for several decades now [1]. In our country, we have experience in prolonged operation of a large-tonnage rectifi cation process for purifying sublimate and high-enrichment Uranium hexafl uoride [2–4]. In order to develop a rectifi cation process, it is necessary to have information on the phase equilibrium of mixtures based on Uranium hexafl uoride and to predict the properties of systems with which it is diffi cult to experiment. Computer methods of calculating steam-water systems have now been developed and are being improved; examples are models of local compositions Wilson, NRTL, UNIQUAC, equations of state SRK, Peng Robinson, and the group model UNIFAC, TTA [5–7]. They are based on the equation of thermodynamic equilibrium between coexisting phases and are generalizations of the Van-der-Waals equation of phase equilibrium, expressed in terms of partial properties [8]. Some forms of this equation are identical to a previously used van-Laar equation expressing the dependence of the coeffi cient of activity of a component on the composition of the solution [9]. Such methods of calculating the liquid–vapor equilibrium in nonideal systems take account of the effect of variable temperature and are convenient for modeling mixtures with an appreciable difference of the boiling temperature of pure components, making it possible to obtain good agreement between the computed and experimental parameters for some solutions. The application of a comparative method for calculating the properties of pure substances and solutions and the characteristics of phase and chemical equilibria is illustrated in the monograph [10]. In the present work, a method is proposed for fi nding parameters that can be used to calculate the vapor–liquid equilibria of mixtures of elemental hexa- and pentafl uorides by means of a comparative method.
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methods of extracting a small quantity of impurities during rectification of Uranium Hexafluoride in fluoride gas reprocessing of spent nuclear fuel
Atomic Energy, 2013Co-Authors: V K EzhovAbstract:Methods for concentrating and extracting a small quantity of volatile impurities of the fluorides of fission products in the rectification method of reprocessing Uranium Hexafluoride are discussed. Such methods are shown to be efficacious during the operation of experimental and commercial facilities for sublimate and radiochemical operations and in Uranium isotope separation plants.
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commercial rectification facility for deep purification of sublimate Uranium Hexafluoride
Atomic Energy, 2007Co-Authors: V K EzhovAbstract:The history of the development of the first domestic commercial rectification facility for deep purification of Uranium Hexafluoride sublimate at the Polimer plant of the Kirovo-Chepets Chemical Works is presented. A description, the technological scheme, and the operating regimes of the facility are described. The results of a chemical analysis of the initial and rectified Uranium Hexafluoride are reported.
Rodney D Hunt - One of the best experts on this subject based on the ideXlab platform.
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ftir spectra of the hydrolysis of Uranium Hexafluoride
The Journal of Physical Chemistry, 1992Co-Authors: Susan A Sherrow, Rodney D HuntAbstract:The hydrolysis of Uranium Hexafluoride has been examined with infrared spectroscopy under three different reaction conditions. First, UF{sub 6} was codeposited with water in excess argon at 12 K. The FTIR spectra of UF{sub 6}/H{sub 2}O mixtures revealed several product absorptions due to the perturbed v{sub 1}, v{sub 2}, and v{sub 3} modes of H{sub 2}O as well as the v{sub 3} mode of UF{sub 6}. These new absorptions have been assigned to the anti-hydrogen-bonded 1:1 complex, UF{sub 6}-OH{sub 2}. Photolysis of this weak complex produced a doublet at 868.2 and 857.1 cm{sup -1}, which has been assigned to the UOF{sub 4}. Next, solid films of UF{sub 6}/H{sub 2}O mixtures were prepared at 12 K and slowly annealed at 242 K. The reaction profile of the UF{sub 6} hydrolysis from UF{sub 6} hydrolysis from UF{sub 6} (or UF{sub 6}-OH{sub 2}) to UOF{sub 4} to UO{sub 2}F{sub 2} was obtained. Finally, UF{sub 6} and H{sub 2}O were reacted at low pressures and ambient temperatures in a new IR gas cell. While no gaseous Uranium oxyfluorides were detected, the final product distribution inside the gas cell did indicate that the fluorinated nickel surface served as a catalyst for the UF{sub 6} hydrolysis.more » 21 refs., 4 figs., 1 tab.« less
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matrix infrared spectra of hydrogen chloride complexes with Uranium Hexafluoride tungsten Hexafluoride and molybdenum Hexafluoride
Inorganic Chemistry, 1991Co-Authors: Rodney D Hunt, Lester Andrews, Mac L TothAbstract:HCl complexes with UF[sub 6], WF[sub 6], and MoF[sub 6] were prepared in solid argon at 12 K. The FTIR spectrum of UF[sub 6]/HCl contained a doublet at 2850.6 and 2849.7 cm[sup [minus]1] due to the hydrogen-bonded UF[sub 6]-HCl complex. In contrast, the HCl interaction with WF[sub 6], as well as MoF[sub 6] produced two distinctly different 1:1 complexes. The 2862.1-cm[sup [minus]1] absorption due to the antihydrogen-bonded complex, WF[sub 6]-ClH, was slightly more intense than the 2866.2 cm[sup [minus]1] absorption due to the antihydrogen-bonded complex, WF[sub 6]-ClH, was slightly more intense than the 2866.2-cm[sup [minus]1] absorption of the hydrogen-bonded complex, WF[sub 6]-HCl. The frequencies and relative intensities of the absorptions for the MoF[sub 6] complexes with HCl were very similar to those of their WF[sub 6] counterparts.
O B Gromov - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic study of the interaction reaction of ammonia and Uranium Hexafluoride
Atomic Energy, 2018Co-Authors: O B Gromov, P I Mikheev, S. O. Travin, D V Utrobin, A A BykovAbstract:Thermodynamic calculations of the interaction of gaseous Uranium Hexafluoride and ammonia were performed. Possible mechanisms for the recovery of Uranium Hexafluoride are examined. It is shown that the Uranium in this system will be recovered mainly due to the ammonia proper and not the formed atomic hydrogen as previously believed. The calculations showed that the calorimetric, theoretical, and actual temperature of the interaction reaction of Uranium Hexafluoride and ammonia is numerically equal to ~0 K, i.e., Uranium Hexafluoride and ammonia react at any temperature. In application to the Kedr apparatus, it is concluded that the reactor walls must be cooled substantially or a cooling gas must be introduced into the reaction zone in amounts sufficient to compensate the heat of reaction in order to avoid an unpredictable rate of the flame process.
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modeling of Uranium oxides hydrofluorination process with areva firm technology malvesi france
Procedia Chemistry, 2014Co-Authors: Aleksandrovich Aleksandr Bykov, O B Gromov, S. O. Travin, P I MikheevAbstract:Abstract The analysis of hydrofluorination process at AREVA plant in Malvesi was carried out as part of the development algorithm aimed at building self-consistent models for chemical technology processes. This algorithm was developed within the framework of the contract for creating a computer-assisted system of simulation and optimization of chemical technology processes on behalf of State Atomic Energy Corporation “Rosatom”. The hydrofluorination process was selected due to Uranium tetrafluopride (UTF) being the main precursor in the process of Uranium Hexafluoride (UHF) production.
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intensification of evaporation of Uranium Hexafluoride
Theoretical Foundations of Chemical Engineering, 2013Co-Authors: A M Belyntsev, O B Gromov, P I Mikheev, A V Ivanov, G S Sergeev, A A Bychkov, S I Kamordin, V I Nikonov, I V Petrov, V A SeredenkoAbstract:The theoretical mechanism of the sublimation of Uranium Hexafluoride are considered. The most contribution to the rate of evaporation of UF6 is introduced by the conductive mode of heat exchange. Various modes of the intensification of the evaporation of Uranium Hexafluoride during the nitrogen supply in pulse mode to the product mass are investigated. The nitrogen supply results in the turbulization of gas flow within a vessel (Re = 2500–4000) and significantly increases the rate of evaporation of Uranium Hexafluoride with the substantial decrease in a weight of the nonevaporable residue of 5.6–1.0 kg. The complex application of the pulse nitrogen supply in combination with heating the bottom of the vessel is the most effective method for evaporating Uranium Hexafluoride. The rate of evaporation of UF6 increases by a factor of almost four in comparison with the design mode. The developed methods are applied in industry and provide the stable operation of Saturn reactors during the conversion of Uranium Hexafluoride into its dioxide.
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neutralizing accidental discharges of Uranium Hexafluoride from the isotope separation plant at the siberian chemical works
Atomic Energy, 2009Co-Authors: O B Gromov, V V Vodolazskikh, P V Zernaev, V I Ivanov, A V Sigailo, M I Sterkhov, V K ProkudinAbstract:The processes occurring during accidental discharges of liquid Uranium Hexafluoride in the production rooms of the Chelnok-T section in the isotope separation plant at Siberian Chemical Combine are examined. The purification system, which uses KhP-MMD and KhP-MD chemical absorbers, permits localizing very quickly any accidental discharges of Uranium Hexafluoride and protect the atmosphere in the plant from harmful effects of fluorine-contained gases. The absorbers effectively catch HF (99.97%) and UF6 (>99.9%) and have a high working capacity 30.5 mass% with respect to the fluorine ion. The system for catching and dispersing harmful contaminants provides the required sanitary standard with respect to atmospheric air on the territory of the plant and at the nearest populated points.
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depleted Uranium Hexafluoride the fluorine source for production of the inorganic and organic compounds
Journal of Fluorine Chemistry, 2009Co-Authors: V V Shatalov, O B Gromov, V A Seredenko, Yu D Kalmakov, A V Ivanov, A V ParfienovAbstract:Abstract The methods of the transfer of depleted Uranium Hexafluoride into the safer chemical forms have been analyzed. The depleted Uranium Hexafluoride is the very valuable source of the high-purity fluorine that it may be used for the production of the pure fluorine-containing compounds. The need for processing of hydrogen fluoride obtained as a result of depleted Uranium Hexafluoride (DUF 6 ) conversion, as a result of its high chemical and toxicological hazard. The methods and ways of fluorine application in different fields of science and technology are contained in DUF 6 . Basic direction of fluorine application, contained in DUF 6 , is nuclear fuel cycle.
