模拟热峰冲击下UO2微观结构的变化

利用分子动力学方法,通过热峰模型模拟了高能辐照下UO2的损伤过程.通过在单次热峰模拟中设定不同入射温度、不同入射半径的热峰,观察到基体中心区域原子获得了能量.在热激活的作用下以压力波的形式向外层快速传递,在原子大量离位的同时也有大量回复在进行.随入射能量的不同,最终形成了非晶态、半非晶、晶态3种微观结构.模拟结果可以较好地重现热峰辐照的物理过程,能够对在实验上无法观测的微小尺度的变化给予直观的描述.

Microstructure Evolution of UO2 Impacted by Simulated Thermal Spike

A thermal spike model has been established and the high energy damage of UO2 was simulated by a molecular dynamics method. Different input temperatures and different input radii were set in single thermal spike simulation. The atoms in the central zone are activated by the thermal energy and passes to the outer layer with pressure wave style fast. The recovery happens simultaneously with a vast number of departure atoms. The final configurations are three types including amorphous, semi-amorphous and crystal. The simulation results can reproduce the physical process of thermal spike irradiation well. The affected zone which is too tiny to be viewed by experimental instruments can be observed directly