High-burn-up structure evolution in polycrystalline UO_(2):Phase-field modeling investigation

作     者：Dan Sun Yanbo Jiang Chuanbao Tang Yong Xin Zhipeng Sun Wenbo Liu Yuanming Li 孙丹;姜彦博;唐传宝;辛勇;孙志鹏;柳文波;李垣明

作者机构：National Key Laboratory of Nuclear Reactor TechnologyNuclear Power Institute of ChinaChengdu 610213China School of Nuclear Science and TechnologyXi’an Jiaotong UniversityXi’an 710049China 

出 版 物：《Chinese Physics B》 (中国物理B(英文版))

年 卷 期：2025年第34卷第2期

页      面：378-386页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.U20B2013 and 12205286) the National Key Research and Development Program of China(Grant No.2022YFB1902401) 

主　　题：high-burn-up structure phase field uranium dioxide gas bubble recrystallization 

摘      要：Understanding the evolution of microstructures in nuclear fuels under high-burn-up conditions is critical for extending fuel refueling cycles and enhancing nuclear reactor *** this study,a phase-field model is proposed to examine the evolution of high-burn-up structures in polycrystalline UO_(2).The formation and growth of recrystallized grains were initially *** was demonstrated that recrystallization kinetics adhere to the Kolmogorov–Johnson–Mehl–Avrami(KJMA)equation,and that recrystallization represents a process of free-energy ***,the microstructural evolution in UO_(2) was analyzed as the burn up *** bubbles acted as additional nucleation sites,thereby augmenting the recrystallization kinetics,whereas the presence of recrystallized grains accelerated bubble growth by increasing the number of grain *** observed variations in the recrystallization kinetics and porosity with burn-up closely align with experimental ***,the influence of grain size on microstructure evolution was *** grain sizes were found to decrease porosity and the occurrence of high-burn-up structures.