Comparison of Technologies for Metal Radioactive Waste Decontamination

A review is made of the growth dynamics of metal radioactive waste on a world scale. The most commonly applied technologies (hydro- and pyrometallurgical) for deactivation of this waste are presented. The implementation of the blocks obtained by remelting for the manufacture of fasteners of nuclear reactors is demonstrated. Based on the conducted experiments and drawn conclusions, the inference is made that the pyrometallurgical methods of processing have greater advantages. The paper exhibits a convincing motivation for the essential necessity of investigation of the metal radioactive waste processing, following the system D&D (deconstruction + deactivation), using effective and environmentally friendly technology

Investigation of Titanium Hydride Produced from Titanium Waste

The work presents an original method for titanium hydride production by hydrogenation and dehydrogenation of titanium waste in a specially designed for this purpose vacuum chamber. Laboratory quantities of titanium hydride were prepared using LaNi5 hydrogen accumulator as a source of pure hydrogen. Chemical, X-ray, DTA, TG and granulometric analysis of the obtained hydride were made. The analyses carried out in the temperature range, 680-1070 К, DTA, TG and mass-spectrometry analysis allowed determining the activation energy of decomposition of the obtained TiH2 which was approximately E = -135.5 kJ/mol and the standard enthalpy of formation ΔH = -140 kJ/mol

A Design of New Brands of Martenzite Steels by Artificial Neural Networks

The paper proposes a model-based approach for the design of martenzite structure steels with improved mechanical and plastic characteristics using proper composition and thermal treatment. For that purpose, artificial neural models approximating the dependence of steels strength characteristics on the percentage content of alloying components were trained. These non-linear models are further used within an optimization gradient procedure based on backpropagation of utility function through neural network structure. In order to optimizing the steel characteristics via its chemical composition, several steel brands with high values of tensile strenght, yield strenght and relative elongation were designed. A steel composition having economical alloying and proper for practical application was determined comparing several obtained decisions. The usage of that steel will lead to lightening of the hardware for automobile industry

Study of the Sintering Process of Iron Powders Coated with Nano-Hydrocarbon and the Resulting Microstructure at Temperatures up to 1200°C

The objective of the research is development and study of a new ecologically friendly and technologically advanced method for introduction of carbon during sintering of low alloyed iron powders ASC 100.29. The method is based on using hydrocarbon coating of the green powder, which transforms into carbon nanolayers between the powder particles, during the sintering process. The method avoids the use of graphite as alloying element and reductant, and allows for a much better homogenization, less porosity and overall increase of the quality of the final sintered product. The research presented is focused on the processes related to apparent density, fluidity and compressibility of the coated powder and resulting porosity after pressing and sintering. The aim is to determine the optimal coating conditions, and to acquire experimental data concerning key processes during the sintering and the originated microstructure. The sintering process was monitored in situ through DTA measurements and measurement of the exhaust gases pressure. Results obtained so far show better handling conditions for the green coated powders, compared to those using classical approach and higher homogeneity of the sintered specimens