Study On The Structure And Chracteritics Of Uranium And Uranium Dioxide By Pseudopotential Plane Wave Method

Uranium is key material in nuclear industrial which has very active chemical property and prone to corrosion if presence of oxygen, water and hydrogen.. As uranium corrodes, its mechanical property degrades, swells and particalizes, harmful to conservation. Under ambient environments, oxidation is the main cause of corrosion. It is beneficial to know the the oxidation kinetic and its influencing factor. The oxidation process may be very complex and involve a number of different physical and chemical processes: adsorption of oxygen, cation or anion transport across the oxide and interface reaction. UO₂ is the main corrosion product and the nature protective layer metallic uranium. Many experiments show that oxygen diffusion through the UO₂ is 'rate controlling step' of oxidation and transport of hydrogen across the UO₂ has great influence on the hydrogenation process. So it is important to investigate the ions diffusion and defect behavior of the UO₂.To study the hydrogen in UO₂, it is important to develop efficient accurate method. We construct the ultrasoft pseudopotential (USPP) of uranium with the USPP we can perform optimization of uranium compound with relative small cost. The stability of different phase of metallic uranium can be replicated by calculations. For simple compound, errors of calculated lattice constant are less...