Fragmentation of Uranium Dioxide after Molten Uranium Dioxide-Sodium Interaction

Molten uranium dioxide structure and dynamics.

Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating,...

Configurational analysis of uranium-doped thorium dioxide

While thorium dioxide is already used industrially in high temperature applications, more insight is needed about the behaviour of the material as part of a mixed-oxide (MOX) nuclear fuel, incorporating uranium. We have developed a new interatomic potential model, commensurate with a prominent existing UO2 potential, to conduct configurational analyses of uranium-doped ThO2 supercells. Using th...

Refinement in the ultrasonic velocity data and estimation of the critical parameters for molten uranium dioxide

Based on the previously reported internal pressure approach and by making use of recent and more accurate experimental measurements on the density, and heat capacity of liquid UO2 up to 8000 K, reliable data on the sound propagation velocity in molten uranium dioxide have been obtained. An equation of state for liquid urania has also been developed which predicts a critical temperature (Tc) 105...

Molecular dynamics analysis of diffusion of uranium and oxygen ions in uranium dioxide

Diffusion behaviours of oxygen and uranium were evaluated for bulk and grainboundaries of uranium dioxide using the molecular dynamics (MD) simulation. It elucidated that oxygen behaved like liquid in superionic state at high temperatures and migrated on sublattice sites accompanying formation of lattice defects such as Frenkel defects at middle temperatures. Formation energies of Frenkel and S...

Mathematical Modeling of Fluorination Reaction of Uranium Dioxide and Evaluation of Existing Gas-Solid Reaction Models