Molecular Dynamics Simulation of Recoil Nucleus Displacement Cascade in Zircon

1998 ◽  
Vol 540 ◽  
Author(s):  
Jean-Paul Crocombette ◽  
Dominique Ghaleb
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Molecular Simulations ◽  
Recoil Nucleus ◽  
Dynamics Simulation ◽  
Local Temperature ◽  
Displacement Cascades ◽  
Displacement Cascade ◽  
Temperature And Pressure

AbstractThe results of molecular simulations of a-recoil nucleus displacement cascades in zircon (ZrSiO4) are presented. The local temperature and pressure are found to increase dramatically during the cascade. The structure of the cascade tracks is amorphous. Its shape has been analyzed in terms of disordered and distorted cations. SiO2 nanophase are found to exist in the tracks consistently with what is observed in the experiments.

Molecular-Dynamics Simulation of Displacement Cascades in Zircon (ZrSiO4)

1997 ◽  
Vol 506 ◽  
Author(s):  
J-P. Crocombette ◽  
D. Ghaleb
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Recoil Nucleus ◽  
Point Of View ◽  
Nuclear Industry ◽  
Dynamics Simulation ◽  
Α Decay ◽  
Displacement Cascades ◽  
Displacement Cascade ◽  
Amorphous Zone

ABSTRACTZircon (ZrSiO4) is of great interest for the nuclear industry as it is one of the new crystalline waste form considered for the disposal of actinides, for example weapons' plutonium in USA. In this study the effects of displacement cascade due to α-decay has been modelled from an atomistic point of view by molecular dynamics simulation using Born-Mayer-Huggins empirical potential. The numerical values of the parameters of this potential have been fitted on structural equilibrium properties of the crystal and on atomic arrangements.Displacement cascades are reproduced by accelerating one of the atoms of the cell, thus modelling the effect of the α-decay recoil nucleus. Kinetic energies up to 2 keV have been introduced. The unfolding of the cascades and the final structures have been studied in detail. The centre of the displacement cascade exhibits an amorphous zone where the zircon structure is completely lost. It contains an assembly of distorted SiO4 tetrahedra and disordered zirconium polyhedra. The zirconium ions (originally surrounded by 8 oxygen atoms) exhibit a decrease in their coordination number to 7 or 6 in agreement with what is observed for zirconium ions in amorphous zircon, zirconia or glasses. The size of the amorphous zone and the number of atoms displaced have been estimated for different recoil energies.The energy stored during the cascade has been calculated. It exhibits an overall good agreement with the available experimental data at complete amorphization.The existence of an amorphous track in our calculated cascades shows that the correct model for the amorphisation process should take into account the existence of a direct impact amorphous zone.

Molecular Dynamics Simulation of the Displacement Cascades in Tungsten with Interstitial Helium Atoms

2014 ◽  
Vol 66 (1) ◽  
pp. 112-117 ◽  
Author(s):  
Xiaodan Yang ◽  
Huiqiu Deng ◽  
Nengwen Hu ◽  
Shifang Xiao ◽  
Cuilan Ren ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Helium Atoms ◽  
Displacement Cascades
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