Recovery and restructuring induced by fission energy ions in high burnup nuclear fuel

Kinoshita, Motoyasu; Yasunaga, Kazufumi*; Sonoda, Takeshi*; Iwase, Akihiro*; Ishikawa, Norito   ; Sataka, Masao; Yasuda, Kazuhiro*; Matsumura, Sho*; Geng, H. Y.*; Ichinomiya, Takashi*; Chen, Y.*; Kaneta, Yasunori*; Iwasawa, Misako*; Onuma, Toshiharu*; Nishiura, Yasumasa*; Nakamura, Jinichi ; Matzke, H. J.*

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.