Study of fission and high-burnup induced restructuring of nuclear fuel ceramics - Applying computer science to investigate kinetic process

The new cross-over project of AECJ was introduced briefly The study is to reproduce process and restructuring at high burnup nuclear fuel; the rim-structure, grain sub-division, cauliflower structure by - computational science - accelerator Irradiation simulating fission events in nuclear fuel. By first principle calculations, electronic structures, lattice parameters, formation energies were successfully reproduced. However, strong correlation of f-electrons were treated by empirical approach of +U. Spin-orbital correlation and excited state are not handled yet. Electronic structures of UO₂ and CeO₂ were compared and resultant difference of material properties are revealed. Lattice defects, produced by irradiation, were investigated step by step from point to clusters. Principally formation energies were calculated. For oxygen defects some detailed analyses are underway. Lattice defects, produced by irradiation, were investigated step by step from point to clusters. Principally formation energies were calculated. For oxygen defects some detailed analyses are underway. Molecular dynamics simulations were performed and continuous change of lattice system was investigated and stabilization of planar structure with precipitated Xenon atoms were confirmed. Lattice defects, produced by irradiation, were investigated step by step from point to clusters. Principally formation energies were calculated. For oxygen defects some detailed analyses are underway. Computational strategy and methodology were discussed for Repeated irradiation, numerous loop of damage quenching and recovery requires new strategy of computation and methodology. Some approaches were briefly introduced.