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 UF 6 (>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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The results of industrial tests of a cascade of chemical absorbents for catching spent halogen-containing processes gases during discharge into the atmosphere are discussed. It is noted that the volume of the discharged gases decreases as a result of CO 2 absorption. The HF and Cl 2 content in passing gas can serve as a criterion for the completion of each catching step; Cl 2 detection after the last step is a service life criterion for all chemical absorbents of a facility without exception. The average catching efficiency is 99.7 and 98.5% with respect to fluorine-and chlorine-containing components, respectively. An approximate calculation of the near-ground concentration of HF and Cl 2 is performed. The gases discharged by the isotope separation plant at the Siberian Chemical Combine were purified at the level of the maximum admissible concentration for the working zone and not at the level of the technical norm established individually for each industrial enterprise. Equipping nuclear fuel cycle enterprises with such systems will make it possible to decrease environmental contamination considerably.Modernized mercerized wood must be tested under the operating conditions of a gas-dust catching facility as the final sanitary step in neutralizing gas mixtures because the halogen-containing substances whose chemical activity is low when interacting with marble dust are not adequately removed. The normalized process discharge from the isotope separation plant Siberian Chemical Combine is 3 mg HF/m 3 . The principal absorbing reagent NaOH in wood absorbents is a chemically more active substance with respect to acid gases than Ca(OH) 2 , which forms the base of the calcium absorbent (CCA) and especially crystalline CaCO 3 which is the base of marble dust. In addition, calcium absorbent does not contain a reducing additive, while in modernized mercerized wood the additive is Na 2 SO 3 , which makes it possible to reduce the comparatively inert compound Cl 2 to HCl and the Cl 2 interacts more actively with sodium hydroxide [1,2]. A factor of no small importance is the proximity of the supplier of chemical absorbents -the expert plant National Technical Center Zapsibpromtekhnologiya (Tomsk) whose capacity reaches to 20 tons/yr [3].Thermodynamic calculations confirmed that alkali-metal hydroxides, as compared with active compounds of other absorbents, are chemically more active with respect to acid substances (Table 1). The change of the Gibbs energy was calculated with respect to reactions of the active component of an absorbent with HF.