Neutralizing accidental discharges of uranium hexafluoride from the isotope separation plant at the Siberian chemical works

Abstract

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.

Study on the Thermal Stability of the Na2UF8 Complex in the Argon Atmosphere

“…The Na 2 UF 8 complex forms during the adsorption of UF 6 on NaF sorbent, and the complex can decompose reversibly to UF 6 and NaF with the increase of the temperature. This reversible reaction between UF 6 and NaF is of great significance for the separation of the volatile impurities from the UF 6 product. − Our previous study indicated that Na 2 UF 8 was stable in anhydrous environment, and the obvious desorption of UF 6 from NaF sorbent occurred when the temperature exceeded 200 °C with a maximal desorption rate of UF 6 at 330 °C. We also found that the desorption behavior of UF 6 from the NaF sorbent in the fluorine atmosphere was similar to that in the argon atmosphere, while the amount of the uranium residue on the NaF sorbent after desorption in the argon atmosphere (1.68 mg U/g NaF) was significantly larger than that in the F 2 atmosphere (0.006 mg U/g NaF) .…”

Reduction of uranium hexafluoride adsorbed on sodium fluoride

“…A possible process of uranium reduction as a result of nuclear-chemical transformations requires study and experimental confirmation.Sorption technologies of catching, separation, decontamination, and salvaging of gaseous mixtures containing uranium hexafluoride, hydrogen fluoride, fluorine, and chlorine trifluoride as well as other volatile fluorides, using other fluoride adsorbents, for example, lithium fluoride, as the adsorbent granular sodium fluoride are finding increasing applications in industrial production and scientific research [1][2][3][4][5][6][7]. The mechanisms of the formation of un-desorbed uranium residue with thermal desorption of uranium hexafluoride from the surface sodium fluoride are examined.…”

“…Sorption technologies of catching, separation, decontamination, and salvaging of gaseous mixtures containing uranium hexafluoride, hydrogen fluoride, fluorine, and chlorine trifluoride as well as other volatile fluorides, using other fluoride adsorbents, for example, lithium fluoride, as the adsorbent granular sodium fluoride are finding increasing applications in industrial production and scientific research [1][2][3][4][5][6][7]. For this reason, some questions arising with the use sodium fluoride as the sorbent are general and require a scientific explanation and subsequent resolution.…”

“…The most likely mechanism of residue formation is partial reduction of hexavalent uranium, which is due to the chemical properties of the system UF 6 The mechanisms of the formation of un-desorbed uranium residue with thermal desorption of uranium hexafluoride from the surface sodium fluoride are examined.…”