The study of damage evolution in silicon carbide bombarded with energetic helium ions is important for the use of this material in future fusion reactors. Heavier inert gas atoms like Ne and Xe have similar behavior o...The study of damage evolution in silicon carbide bombarded with energetic helium ions is important for the use of this material in future fusion reactors. Heavier inert gas atoms like Ne and Xe have similar behavior of diffusion and clustering with helium, and the comparison of damage accumulation behavior between energetic helium and heavier inert gas ions can reveal important aspects of underlying mechanisms. As an extension of展开更多
The synthesis of the super-heavy nuclei and the study of their properties attract more and more attentions in recent years. The He-jet+MG wheel technique with which ^259Db and ^265Bh were synthesized at IMP has reache...The synthesis of the super-heavy nuclei and the study of their properties attract more and more attentions in recent years. The He-jet+MG wheel technique with which ^259Db and ^265Bh were synthesized at IMP has reached its limits due to the short life-time and rare amount of the products. In order to identify the nuclei with higher Z, a device for separating the interested nuclei from the heavy background is definitely needed.展开更多
The analysis of the interaction of hydrogen, nitrogen （and their isotopes） with tungsten is important, since this material is a strong candidate to form the first wall of fusion reactors for both magnetic and inerti...The analysis of the interaction of hydrogen, nitrogen （and their isotopes） with tungsten is important, since this material is a strong candidate to form the first wall of fusion reactors for both magnetic and inertial confinement, and these atoms have a very sensitive （desired and unwanted） interaction with it. For this purpose, we study the effects and electronic state densities of atomic hydrogen and nitrogen in pure tungsten, in order to analyze some important properties such as the density of states of the system. Focusing on this application, this work is a preliminary study of the behavior of atoms of hydrogen and nitrogen, on a surface of tungsten on the three sites of the cell： top, hollow and bridge. We use a program simulation based on the DFT （density functional theory） implemented in the Open-Source Code Quantum Espresso, in order to obtain the adsorption energy and the density of states of the systems.展开更多
Nuclear fuel based on uranium metal alloys is utilized in research and test reactors. For the purpose of the reduction of fuel enrichment, high densities of uranium-235 in this kind of fuel are needed. This can be ach...Nuclear fuel based on uranium metal alloys is utilized in research and test reactors. For the purpose of the reduction of fuel enrichment, high densities of uranium-235 in this kind of fuel are needed. This can be achieved when uranium alloys are used containing elements such as Zr, Mo and Nb. The construction of fuel element with high-uranium density requires materials with low cross sections for neutron absorption, stability under irradiation and absence of the chemical interactions between the fuel and cladding elements. In case of U-Zr-Nb alloys, Zry （zircaloy） cladding is a better option due to the fact that they have a higher chemical compatibility when compared with the use of aluminum alloys. This study aims to develop plate type nuclear fuel using the U-2.5Zr-7.5Nb alloy dispersed in Zry. Powders of this uranium based alloy and Zry were obtained by hydriding-dehydriding process. These powders were homogenized, compacted in pellet that was sandwiched in plates and frame of Zry. This assembly was hot rolled forming the dispersion fuel miniplate.展开更多
文摘The study of damage evolution in silicon carbide bombarded with energetic helium ions is important for the use of this material in future fusion reactors. Heavier inert gas atoms like Ne and Xe have similar behavior of diffusion and clustering with helium, and the comparison of damage accumulation behavior between energetic helium and heavier inert gas ions can reveal important aspects of underlying mechanisms. As an extension of
文摘The synthesis of the super-heavy nuclei and the study of their properties attract more and more attentions in recent years. The He-jet+MG wheel technique with which ^259Db and ^265Bh were synthesized at IMP has reached its limits due to the short life-time and rare amount of the products. In order to identify the nuclei with higher Z, a device for separating the interested nuclei from the heavy background is definitely needed.
文摘The analysis of the interaction of hydrogen, nitrogen （and their isotopes） with tungsten is important, since this material is a strong candidate to form the first wall of fusion reactors for both magnetic and inertial confinement, and these atoms have a very sensitive （desired and unwanted） interaction with it. For this purpose, we study the effects and electronic state densities of atomic hydrogen and nitrogen in pure tungsten, in order to analyze some important properties such as the density of states of the system. Focusing on this application, this work is a preliminary study of the behavior of atoms of hydrogen and nitrogen, on a surface of tungsten on the three sites of the cell： top, hollow and bridge. We use a program simulation based on the DFT （density functional theory） implemented in the Open-Source Code Quantum Espresso, in order to obtain the adsorption energy and the density of states of the systems.
文摘Nuclear fuel based on uranium metal alloys is utilized in research and test reactors. For the purpose of the reduction of fuel enrichment, high densities of uranium-235 in this kind of fuel are needed. This can be achieved when uranium alloys are used containing elements such as Zr, Mo and Nb. The construction of fuel element with high-uranium density requires materials with low cross sections for neutron absorption, stability under irradiation and absence of the chemical interactions between the fuel and cladding elements. In case of U-Zr-Nb alloys, Zry （zircaloy） cladding is a better option due to the fact that they have a higher chemical compatibility when compared with the use of aluminum alloys. This study aims to develop plate type nuclear fuel using the U-2.5Zr-7.5Nb alloy dispersed in Zry. Powders of this uranium based alloy and Zry were obtained by hydriding-dehydriding process. These powders were homogenized, compacted in pellet that was sandwiched in plates and frame of Zry. This assembly was hot rolled forming the dispersion fuel miniplate.
