[en] Full text: Institute of Atomic Energy prepared and conducted the experiments the purpose of researching a possibility of applying of stainless steel electric slag remelting for its decontamination from radioactive contamination. The activities were conducted at participating of the specialists of Kurgan State University, Kurgan (Russian Federation). A stand, which includes the electroslag furnace (power - 150 kW, current - to 3000 A) and auxiliary equipment (the system of common and special ventilation, system of remote control, system of parameters measuring and registering and others) was created to conduct the experiments. The properties of slag compositions were researched in the course of experiments preparation. Oxide (CaO-Al₂O₃ - CaO-SiO₂ - MgO-B₂O₃) and fluoride-oxide (CaF₂-SiO₂ - MgF₂-SiO₂) slag systems and some their modifications were chosen to research physical and chemical properties. Physical and chemical properties of the slag systems were experimentally researched and it included: measuring of surface tension using the method of maximum pressure in a gas bubble (at the same time density was measured); measuring of slag alloys electrical conductivity; measuring of melt volt-ampere characteristics. The flue tubes of high temperature reactor gas cooling KET technological channels were chosen as a source of radioactive contaminated stainless steel. This reactor is meant for testing of the fuel pin and FA of the nuclear pulse propulsion. Decontamination effect for all the remelted flue tubes was indirectly confirmed by the outcomes of measuring of radioactive radiation dose rate of the materials, extracted of the crystallizer after experiments finishing. The outcomes of the experiments show that the following processes pass at electroslag remelting of radioactively contaminated steel: uranium extraction from steel; uranium transfer from steel to slag; saving or insignificant modification of steel initial composition; radionuclides deposing on the special ventilation system filters. It is supposed to continue the researches with the purpose of obtaining of statically and methodically grounded outcomes, at that the following is required: improve the method of measuring of uranium content in the remelted electrodes; improve the method of measuring of uranium content by applying the new devices and developments of the software for in-etalon method of steel samples element composition determination; apply the factor approach to conduction of the experiments for examining influence of such factors as uranium initial mass in the electrode, remelting speed, flux mass, flux composition on degree of steel decontamination from uranium

[en] There were conducted in-pile experiments for grounding of realization possibility of the specified diagram of energy release rate in the experimental channels with model FA of fast reactor. There have been received data on reactivity effects caused by fuel replacement along reactor IGR central experimental channel. The data are necessary for grounding of safety of the experiments being planned. There have been performed researches on determination of interrelation between neutron flux distributing and fuel state in the central experimental channel. As fuel compactly bunched pellets of WWER-1000 type with enrichment of 4.4% by U²³⁵ were used. Measuring of neutron flux fluence was conducted with the use of activation detectors (static experiments without fuel location change) and small-size neutron chambers (dynamic experiments with fuel location change). There have been accomplished researches of impurity gases content in fuel of WWER-1000 type with enrichment of 4.4% by U²³⁵ . With this aim there have been conducted pressure measuring in the sealed cavity where fuel melting were being conducted. Energy release in fuel was provided at realization of controlled neutron impulse at IGR reactor

[en] ESR (electroslag remelting) facility is meant for researches conducting on decontamination of radioactive stainless steel by electroslag remelting The aim of the research is optimization of fluxes content and steel remelting conditions at which metal decontamination of radioactive contamination will take place, and the ingots received at that will be useful for the further usage without additional remelting. Research outcomes can be used for a long time in the Republic of Kazakhstan which possesses considerable part of global uranium resources and production capacities on uranium production and refinement and, consequently, has considerable quantity of radioactively contaminated materials. (author)