CAJ | 학술논문

采用基于刚性离子势的分子动力学模拟方法初步计算了UO2晶体中(100),(110)和(111)3种低密勒指数晶面在300—1500 K范围内的表面能大小.结果表明,3种晶面的表面能大小随温度的升高而降低,与实验结果趋势一致;原子排列最紧密的(111)晶面具有最低的表面能,3种晶面的表面能大小从高到低依次为(100),(110)和(111)晶面;达到平衡状态下的表面层原子相对于体内原子层在表面的法线方向上发生了明显的压缩并且表面层原子的对称性也降低了,表面原子的弛豫效应一直影响到了第5层.计算研究结果将有助于深入认识UO2燃料中裂变气体气泡的聚集长大以及燃料的辐照肿胀开裂行为.
채용기우강성리자세적분자동역학모의방법초보계산료UO2정체중(100),(110)화(111)3충저밀륵지수정면재300—1500 K범위내적표면능대소.결과표명,3충정면적표면능대소수온도적승고이강저,여실험결과추세일치;원자배렬최긴밀적(111)정면구유최저적표면능,3충정면적표면능대소종고도저의차위(100),(110)화(111)정면;체도평형상태하적표면층원자상대우체내원자층재표면적법선방향상발생료명현적압축병차표면층원자적대칭성야강저료,표면원자적이예효응일직영향도료제5층.계산연구결과장유조우심입인식UO2연료중렬변기체기포적취집장대이급연료적복조종창개렬행위.
@@@@Molecular dynamics simulation based on the rigid-ion potential is carried out to investigate the surface energies of low miller index crystallographic faces such as (100), (110) and (111) in UO2 in a temperature range of 300 K–1500 K. The results indicate that the surface energies of the three low miller index crystallographic faces decline gradually with temperature rising, and the variation of the surface energy with temperature is confirmed to be consistent with the experimental data. The (111) crystallographic face which is the closest surface has the lowest surface energy;the (100) crystallographic face has the biggest surface energy;the (100) crystallographic face has a surface energy in between them. The surface atoms have compressed towards the vertical line of surface with respect to the inside atoms layer obviously. The symmetry of surface atoms declines. Surface phenomena such as relaxation and reconstruction occur on the surface atoms and the relaxation effect extends to the five layers. The results presented in the study are useful for understanding the behaviors of fission gas bubbles growing up and cracking up due to the swelling in fuels under the irradiation.