Liquid structure of UO2 and UCL3 and freezing in halide salts

This thesis aims to investigate the static structure and transport properties of molten UCl3 and UO2 and to study the static freezing criterion of Halide salts. UCl3 is a typical component of phyrochemical process in the area of nuclear fuel cycle technology and UO2 is one of the important nuclear fuels. It is vital to know the high temperature behavior of the nuclear fuels during an accident. The static structure is calculated by solving the Ornstein-Zernike integral equation of liquid state theories in conjunction with Hypernetted-Chain approximation together with a rigid ion potential. The transport properties of these systems are investigated via Molecular Dynamics simulation done by the other members of our research group using the model potential of this work. Result are in agreement with available experimental data in literature and have an important contribution to understand the behavior of these dangerous systems at high temperature. In the second part of this work freezing criterion and mechanism of halide salts are investigated using liquid state theories together with the proper rigid ion potential. The validity of the static criterion that the amplitude of the principal peak of the liquid structure factor has a constant value along the freezing line for halide salts is investigated and it?s concluded that the criterion is restricted to the number concentration. Moreover the distribution of the first maximum in the static dielectric function is determined by the concentration and the character of ion mobility. Keywords: UO2, UCl3, superionic conductors, Halide salts, liquid state theories, static structure, freezing criterion