THE EFFECTS OF HIGH TEMPERATURE HELIUM GAS ON THE FRACTURE BEHAVIOUR OF ODS MA957

Oxide-dispersion-strengthened steel (ODS) MA957 has been studied as a candidate material for Tritium Breeding Blanket for fusion reactors with helium coolant, where temperatures 250-650 degrees C are expected. Helium is one of type as primary coolant in High Temperature Reactor and Gas Cooled Fast Reactor with working temperature 500-1000 degrees C. \n\nThis work presents results of the study of behaviour of ODS (MA957) under influence of high temperature helium environment. Microstructure of the material and the interaction with He was investigated. The average exposure temperature was held at 720 degrees C. Subsequently, the surface changes were determined. Impact testing and material surfaces were studied in detail by means of SEM and TEM microscopy. It is essential to understand the He effect on microstructure and mechanical properties of structural materials since the He embrittlement in TBB may be significant

Reduction of Content of Lead and Zinc from Wastewater by Using of Metallurgical Waste

The aim of this paper was to study the sorption properties of a blast furnace sludge used as the sorbent. The sorbent was utilized for reduction of content of lead and zinc ions. Sorbent utilized in this work was obtained from metallurgical industry from process of wet gas treatment in iron production. The blast furnace sludge was characterized by X-Ray diffraction, scanning electron microscopy, and XRFS spectroscopy. Sorption experiments were conducted in batch mode. The sorption of metal ions in the sludge was determined by correlation of adsorption isotherm models. The adsorption of lead and zinc ions was best fitted with Langmuir adsorption isotherms. The adsorption capacity of lead and zinc ions was 53.8 mg.g-1 and 10.7 mg.g-1, respectively. The results indicated that blast furnace sludge could be effectively used as secondary material and could be also employed as a low-cost alternative for the removal of heavy metals ions from wastewater

Evaluation of microstructure of the steels after exposure in supercritical CO2

The Brayton cycle with supercritical carbon dioxide is considered as an innovative technology with the potential to replace conventional steam cycles. The optimization of the supercritical CO2 cycle (sCO2) is necessary and important to achieve the required thermal cycle parameters. The above optimization focuses on the setting of the energy cycle as such, the design solution of the individual components and, the last but not least, on the selection of suitable construction materials. Due to the operating conditions, namely temperatures exceeding 550 °C and pressure up to 25 MPa, material research is one of the important areas of the research and development of sCO2 energy cycles. Construction materials for sCO2 power cycle equipment include HR6W, T92 and Haynes HR235 alloys. This work presents results of the corrosion test, in which samples of these materials were exposed to sCO2 at 550 °C and 25 MPa for 1000 hours. Corrosion after exposure was examined using a light optical microscope (LOM) and a scanning electron microscope (SEM). The significant differences in corrosion attack between the investigated materials and the formation of a protective oxide layer on the surface were observed

Influence of surface treatment on corrosion resistance of steel in liquid Pb

This work deals with behaviour of steel in liquid lead environment and possibilities of corrosion resistance improvement. Liquid metal cooled systems are under wide investigation and development and represent a good alternative. It is necessary to find materials, which would be affected by liquid lead minimally. Austenitic steel 316L without coating and coated with TiSiC was studied in flowing liquid lead. Conditions of the experiment simulated real environment of the system. Deposition of protective barrier reduced the metals dissolution and diffusion of liquid lead into the steel substrate, degradation of substrate due to high temperature and mechanical stress. Presence of Si in the layer increased the surface ability to form stabile oxide and contribute to steel´s protection