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Ichinomiya, Takashi*; Uberuaga, B. P.*; Sickafus, K. E.*; Nishiura, Yasumasa*; Itakura, Mitsuhiro; Chen, Y.*; Kaneta, Yasunori*; Kinoshita, Motoyasu
Journal of Nuclear Materials, 384(3), p.315 - 321, 2009/02
Times Cited Count：32 Percentile：88.55(Materials Science, Multidisciplinary)We studied the migration dynamics of oxygen point defects in UO which is the primary ceramic fuel for light-water reactors. Temperature accelerated dynamics simulations are performed for several initial conditions. Though the migration of the single interstitial is much slower than that of the vacancy, clustered interstitial shows faster migration than those. This observation gives us important insight on the formation mechanism of high-burnup restructuring, including planar defects and grain sub-division (the rim structure), found in UO.
Ichinomiya, Takashi*; Nishiura, Yasumasa*; Itakura, Mitsuhiro; Kinoshita, Motoyasu
no journal, ,
Migration of oxigen vacancies/interstitials in uranium dioxide crystal is supposed to play a crucial role for the formation of rim-structure. However, the time-scale of oxide interstitial migration is beyond the feasibility of molecular dynamics simulations. In this presentation, we will present results of simulations which deal with longer time-scale.
Kinoshita, Motoyasu; Chen, Y.*; Kaneta, Yasunori*; Geng, H. Y.*; Iwasawa, Misako*; Onuma, Toshiharu*; Ichinomiya, Takashi*; Nishiura, Yasumasa*; Itakura, Mitsuhiro; Nakamura, Jinichi; et al.
no journal, ,
no abstracts in English
Kinoshita, Motoyasu; Yasunaga, Kazufumi*; Sonoda, Takeshi*; Iwase, Akihiro*; Ishikawa, Norito; Sataka, Masao; Yasuda, Kazuhiro*; Matsumura, Sho*; Geng, H. Y.*; Ichinomiya, Takashi*; et al.
no journal, ,
We show the outline of achievements of New Cross Over (NXO) project. Concerning the grain subdivision of ceramics fuel at high burnup, we are trying to clarify the mechanisms and to develop the simulation methods. The main high lights are as follow as: (1) We have reproduced the grain subdivision of CeO, by means of ion implanter and TUNDEM accelerator. (2) We performed computational science study concerning the relocation of oxygen. In case of oxygen exess conditions, first principal calculation reproduced the orderring structure. TAD calculation shows that the exess oxygen compose clusters and diffuses rapidly even if low temperature.
Chen, Y.*; Kaneta, Yasunori*; Geng, H. Y.*; Shang, J. C.*; Iwasawa, Misako*; Onuma, Toshiharu*; Sonoda, Takeshi*; Ichinomiya, Takashi*; Suzudo, Tomoaki; Itakura, Mitsuhiro; et al.
no journal, ,
The outcome of the New Crossover Project Study is outlined. The computational results includes the ab-initio study, molecular dynamics, statistical dynamics/thermal dynamics and meso-scopic modeling, and the experimental results given by an accelerator is also mentioned. Finally, we mention the future plans and the problems.
in the presence of defects of metal latticeIchinomiya, Takashi*; Nishiura, Yasumasa*; Itakura, Mitsuhiro; Kinoshita, Motoyasu
no journal, ,
The effect of lattice defects in UO such Uranium vacancy and Xe atom on the diffusion of oxygen vacancy has been investigated by temperature accelerated MD simulations. U-vacancy was found to have very low mobility and its migration was very rare. O-vacancy is bound to this U-vacancy with 0.76 eV bounding energy. From these results, we found that O-vacancy diffusion is suppressed by U-vacancy.
