Molecular dynamics simulation of fast particle irradiation to the GdO-doped CeO

GdOを添加したCeOにおける高速重粒子照射の分子動力学シミュレーション

篠嶋 妥*; 安島 直紀*; 長田 卓也*; 石川 法人   ; 岩瀬 彰宏*

Sasajima, Yasushi*; Ajima, Naoki*; Osada, Takuya*; Ishikawa, Norito; Iwase, Akihiro*

核燃料の初期燃焼を制御するために添加される(中性子吸収断面積の高い)GdOによる照射影響の違いを調べるために、GdO添加した核燃料模擬物質CeOにおける高速重粒子照射の分子動力学シミュレーションを行った。高速重粒子の通過の0.3ピコ秒後、通過軌跡付近が非晶質化し、3ピコ秒後には急速に結晶が回復する現象が見られた。GdO添加に伴い、照射損傷が顕著になる傾向が観測され、過去の照射実験結果と同じ傾向であることが分かった。

The structural relaxation caused by the high-energy-ion irradiation of CeO with GdO addition was simulated by the molecular dynamics method. The amount of GdO was changed. As the initial condition, high thermal energy was supplied to the individual atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The potential proposed by Inaba et al. was utilized to calculate interaction between atoms. The supplied thermal energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it dissipated in the specimen. By increasing the concentration of GdO, more structural disorder was observed in the sample, which is consistent to the actual experiment.