学术报告:Computer Simulation of Primary Radiation Damage and Long-term Defect Evolution in Nuclear Materials
报告题目: Computer Simulation of Primary Radiation Damage and Long-term Defect Evolution in Nuclear Materials
报 告 人: 李永钢(中国科学院固体物理研究所) 报告时间:2018年6月20日(星期三)上午13:00 报告地点:嘉定园区学术活动中心302会议室 报告简介: Two major challenges for modeling of radiation damage effects in nuclear materials are how to accurately and effectively describe the interaction of energetic particles with arbitrary complex 3D structures and atomic diffusion events across a wide time-scale (ns - year) at finite temperature. Two new models are thus developed to meet these requirements: a) A universal, open-source and computationally efficient 3D Monte Carlo code, IM3D, has been developed to study ion implantation, sputtering and primary damage in complex nuclear materials. IM3D is based on fast indexing of scattering integrals and the SRIM stopping power database, and allows the user a choice of Constructive Solid Geometry (CSG) or Finite Element Triangular Mesh (FETM) method for constructing 3D shapes and microstructures. b) A spatially resolved cluster dynamics (CD) model, IRadMat, has also been developed for describing the generation, diffusion, reaction and accumulation of defects in materials under ion or neutron irradiation. IRadMat is improved by taking account multi-irradiation fields, ternary defects, multiple degrees of freedom, and multi-scales into the CD model. A sequential multi-scale modeling framework is thus constructed by coupling these two new models with atomistic approaches. Key issues from primary radiation damage to long-term defect evolution in Fe and W are finally studied based on this framework: 1) a concurrent cascade-annealing model for primary defect production and relaxation, 2) the effect of grain size on H/He retention and neutron irradiation damage, and 3) the effect of spatial correlations in cascades on long-term material damage.