Molecular Dynamics Simulation of Thermal and Thermodynamical Properties of ThO2 [ ]


Nuclear energy has become a very important source of energy, realising the low efficiency and low productivity of fossil fuels. The nuclear fission process generates heat which is further removed by the coolant and using steam and turbines, electrical energy is produced. And for a stable fission reaction, nuclear reactor design and fuel composition alongwith storage of spent fuel and its reprocessing need to be studied, both theoretically and experimentally (if possible). Molecular Dynamics Simulation is an atomistic approach towards predicting the behavior of materials using the classical equations of motion (Newton’s Laws of Motion). This paper showcases the close results produced by the simulation by using two inter-atomic potential set of parameters for ThO2. One is Buckingham potential and the other being Buckingham-Morse-Many Body potential. ThO2 based materials are important fuel for various reactor systems (conventional Pressurised Water Reactors (PWR), Advanced Heavy Water Reactors (AHWR)) owing to a number of neutronic properties. Hence, it clearly needs an experimental database of properties like melting point, density, thermal expansion and thermal conductivity in order to meet the fuel requirements. However, due to extensive as well as expensive safety precautions, not all the properties can be determined at every required temperature experimentally. Hence, classical Molecular Dynamics (MD) is an efficient simulation technique to obtain the same. It was observed that Linear Thermal Expansion parameter was predicted very accurately by both the potentials. Moreover, Melting Point as well as single crystal elastic constants’ prediction was very close to the experimental value.