Radionuclides in Irradiated Graphite of Industrial Uranium–Graphite Reactors: Effect of Irradiation and Thermochemical Treatment on the Graphite Structure

The structure of irradiated graphite from decommissioned industrial uranium–graphite reactors was studied. The extent of disturbance of the graphite structure is closely correlated with temperature and integral neutral fluence. The perfection of the structure of graphite samples (data of X-ray diffraction and Raman spectroscopy) does not correlate with their radioactivity, which is due to low absolute concentration of the radionuclides. Mapping of the samples using Raman spectroscopy reveals spatial heterogeneity of the distribution of graphite lattice damages, which casts doubt on the representativeness of the spectra of individual points. The spatial distribution of domains differing in the crystal lattice perfection was studied for the first time and was compared with the radionuclide distribution. Satisfactory correlation between the radiographic and spectroscopic mapping data is observed for some samples. Irradiated graphite is strongly textured and contains amorphous microvolumes, which are probably radionuclide carriers. Thermochemical treatment (oxidation in O₂, thermal shock) leads to degradation of the irradiated graphite structure on the submicron level, accompanied by a drastic decrease in the mechanical strength of the samples.     

Creating Lithographic Pictures Using Faceted Zinc Oxide Microparticles on a Silicon Substrate

Lithography techniques compatible with silicon technology have been developed within the hydrothermal method. Topological layouts were formed by faceted microcrystals with the developed surface. The prospects for implementing new hierarchical structures are of special interest.     

Temperature stresses in a multilayer hollow spherical body under heating by steady sources

Closed analytical solutions are obtained of steady-state problem of heat conduction and static thermoelasticity for a multilayer hollow spherical body heated by steady sources.     

Effect of a transverse entrainment flow on the characteristics of a turbulent jet

We have experimentally investigated the influence of a transverse entrainment flow (wind) on the trajectory of a turbulent jet, as well as on the distribution of the concentration of the gas being discharged along that jet (hydrogen, helium, nitrogen). The entraining flow of air is formed in open space. Its trajectory falls out along points corresponding to the maximum concentrations in the lateral cross section of the jet. We have derived empirical relationships between the jet trajectory and the gas-concentration distribution along that trajectory in their dependence on the hydrodynamic parameter.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 2, pp. 188–191, August, 1990.     

Reduction of iron oxides during the pyrometallurgical processing of red mud

The results of experiments on the use of red mud in traditional pyrometallurgical processes and plants are presented. The red muds of the Ural Aluminum Plant (UAZ, Kamensk-Ural’skii) and the Alyum Plant (Tul’chiya) are shown to have similar phase and chemical compositions. The morphology of the iron oxides in red mud samples taken from mud storage is studied by Mössbauer spectroscopy. It is found that the metallic (cast iron) and slag phases that form during the pyrometallurgical processing of red mud by melting with a carbon reducer in the temperature range 1200–1500°C are clearly separated. Cast iron can be used in steelmaking, and the slag can be used for hydrometallurgical processing and extraction of nonferrous metals and for the building industry after correcting its composition.     

A method of measuring and recording the pressure of a granular medium

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 4, pp. 27–28, April, 1992.