No abstract
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.In 1970, F. I. Novoselov and V. S. Simonenko -the directors of a division producing uranium hexafluoride at the Polimer plant, which quickly became part of the Kirovo-Chepets Chemical Works -paid a visit to I. K. Kikoin, who was the head of a scientific division at the I. V. Kurchatov Institute of Atomic Energy. They told him about the desire to build in this division a rectification facility for obtaining uranium hexafluoride with a high degree of purity and requested that he provide scientific guidance for this project and organizational assistance. It was natural to turn to Kikoin for this, because at the end of the 1950s the rectification method for purifying uranium hexafluoride as a raw material and as a material obtained from irradiated nuclear fuel was studied in a division which he headed. The first domestic experiment in this direction is the thesis work performed by V. A. Legasov under the direction of O. G. Lebedev. They distilled a mixture obtained by dissolving irradiated uranium metal in liquid chlorine trifluoride.Subsequently, the properties of dilute solutions based on uranium hexafluoride were studied [1], and investigations of the phase equilibria of mixtures of hexa-and pentafluorides of metals with one another and with the hydrogen fluoride were performed, the phenomenon of azeotropism and separation of such systems was investigated [2][3][4][5][6][7], and the kinetic and hydrodynamic features of the rectification of mixtures of uranium hexafluoride were examined [8].Thus, the investigations performed at the Kurchatov Institute of Atomic Energy formed the physicochemical foundations of a method for rectification of uranium hexafluoride, and the operation of large facilities at the Urals Electrochemical Works, the Siberian Chemical Works, and the Industrial Association Élektrokhimicheskii Zavod with the participation of the staff of the Institute confirmed that the rectification purification of uranium hexafluoride is highly efficient and the method is reliable and easy to implement technologically.One motive for the interest shown by the leadership of the Kirovo-Chepets Chemical Works in improving the purity of the uranium hexafluoride produced was that the new centrifuge equipment used at the plants to separate uranium isotopes required an initial product with minimal impurity content. The lower content of impurities in the initial product increase the reliability of gas centrifuges, decreased the material flows processed in the purification cascades and in the uranium recovery facilities, and improved the technological parameters of the uranium hexafluoride evaporation unit. In addition...
The experimental coefficients of permeability of fluorine, hydrogen fluoride, and uranium and tungsten hexafluorides through nonporous films consisting of certain fluorine resistant polymer materials are presented. It is shown that the membrane method of removing hydrogen fluoride from fluorine and uranium and tungsten hexafluorides is attractive.Membrane technology for separating gas mixtures is undergoing intensive development. The attention being given to this technology is largely due to the development of the chemistry and technology of polymer materials, which make it possible to synthesize polymer materials with prescribed properties and to make different articles from these materials, including films and fibers with an extremely thin nonporous diffusion layer, which have been termed asymmetric polymer gas membranes. As a result of the absence of pores in the diffusion layer, a polymer membrane retains the separation properties characteristic of the polymer and the thinness of the layer (several microns) determines its high specific capacity.The permeability coefficients of a large number of polymers and block-copolymers for different gases are presented in handbooks, for example, [1]. However, the information on the permeability of fluorine-stable polymer materials, which are conventional for the nuclear industry, refer only to noncorrosive gases such as nitrogen, oxygen, helium, water vapor, and certain hydrocarbons [2]. For this reason, it seemed interesting and helpful to investigate the permeability of the fluoropolymers widely used in the nuclear industry for gases in the main process flows in sublimate production and in uranium isotope separation plants.One modification of fluoroplastic-4 (F-4NA) and the best known fluorine-stable block-copolymers based on vinylidene fluoride F-42, -23, and -26, produced by the Polimer plant at the Kirovo-Chepetskii Chemical Works were chosen as the object of investigation. The film samples made of these materials were first evacuated for a period of one day at pressure ∼10 Pa to remove any volatile organic substances that could be present and checked for the absence of pores by measuring the rate of helium permeation.Fluorine, hydrogen fluoride, and uranium and tungsten hexafluorides were chosen as the gases. Hydrogen fluoride was of special interest, since the removal of fluorine obtained by electrolysis in sublimate production and uranium hexafluoride from it requires, once again, finding the optimal solution. All gases were first subjected to deep purification by rectification. Fluorine was purified on a cryogenic rectification setup [3]. All other substances were rectified at 80-100 °C in a packed column filled with a fine spiral pakcing. The purity of the rectified substances was checked by the spectral method and hydrogen fluoride and tungsten and molybdenum hexafluorides were additionally checked by measuring the saturated vapor pressure at different temperatures.The gas permeability coefficients of fluorine and fluorine-containing gases were determined by t...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.