MOLECULAR DYNAMICS SIMULATION OF UO2: AN ALTERNATIVE RIGID ION MODEL POTENTIAL

A semi-empirical effective interionic potential model has been parameterized to investigate UO2 by molecular dynamics simulation technique. The simulations were performed in the constant pressure–temperature ensemble between 300 K–3200 K at 100 K intervals. The pair distribution functions and coordination numbers signal the onset of structural changes at temperatures in accord with the Bredig transition and melting. The oxygen ion diffusion coefficients calculated from the mean square displacements markedly increase the liquid like value at T > 2100 K. The transition to the superionic state and melting are well reproduced within the limitations of a rigid ion potential.

[1]  Marc Hou,et al.  Comparison of interatomic potentials for UO2. Part II: Molecular dynamics simulations , 2008 .

[2]  Marc Hou,et al.  Comparison of interatomic potentials for UO2. Part I: Static calculations , 2007 .

[3]  P. Madden,et al.  Structural and transport properties in the Ag3SI system: a molecular dynamics study of alpha, beta and molten phases , 2004 .

[4]  H. S. Kamath,et al.  Classical molecular dynamics simulation of UO2 to predict thermophysical properties , 2003 .

[5]  Kazuhiro Yamada,et al.  Evaluation of thermal properties of uranium dioxide by molecular dynamics , 2000 .

[6]  J. K. Fink,et al.  Thermophysical properties of uranium dioxide , 2000 .

[7]  P. Madden,et al.  Quadrupole Polarization in Simulations of Ionic Systems: Application to AgCl , 1996 .

[8]  T. Karakasidis,et al.  A comment on a rigid-ion potential for UO2 , 1994 .

[9]  M. Gillan,et al.  The dynamical simulation of superionic UO2 using shell-model potentials , 1994 .

[10]  C. Ronchi,et al.  Premelting transition in uranium dioxide , 1993 .

[11]  M. Gillan,et al.  A molecular dynamics study of solid and liquid UO2 , 1988 .

[12]  P. Vashishta,et al.  Ionic motion in superionic Ag2S , 1985 .

[13]  Michael T. Hutchings,et al.  Observation of Oxygen Frenkel Disorder in Uranium Dioxide above 2000 K by Use of Neutron-Scattering Techniques , 1984 .

[14]  Priya Vashishta,et al.  Structural Transitions in Superionic Conductors , 1983 .

[15]  P. Vashishta,et al.  Ionic motion in. cap alpha. -AgI , 1978 .

[16]  J. Marin,et al.  Uranium and oxygen self-diffusion in UO2 , 1969 .

[17]  J. Belle,et al.  OXYGEN ION SELF-DIFFUSION IN URANIUM DIOXIDE , 1961 .

[18]  G. J. Hyland,et al.  The origin of the specific heat anomaly in solid urania , 1983 .