UO2-x燃料芯块的晶粒生长动力学  

Grain Growth Kinetics of UO2-x Fuel Pellet

作　　者：尹邦跃[1] 吴学志[1] 魏国良[1] 屈哲昊[1] 郑新海[1] 王轩[1] 任劲如 YIN Bangyue;WU Xuezhi;WEI Guoliang;QU Zhehao;ZHENG Xinhai;WANG Xuan;REN Jinru(Division of Reactor Engineering Technology Research,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院反应堆工程技术研究部,北京102413

出　　处：《原子能科学技术》2021年第2期296-304,共9页Atomic Energy Science and Technology

基　　金：国防基础科研基金资助项目。

摘　　要：本文采用恒速升温和等温烧结实验方法研究了亚化学计量UO2-x燃料芯块的晶粒生长动力学。结果表明,以UO2+x+5%U为原料,可得到密度为94.91%TD~96.23%TD(TD为理论密度)、O与U的原子个数比为1.975~1.990的合格的亚化学计量UO2-x燃料芯块;在烧结温度≤1 650℃时晶粒生长速率较低,在烧结温度≥1 750℃时晶粒生长速率较高;初始晶粒尺寸G0不能忽略不计,亚化学计量UO2-x燃料芯块的晶粒生长动力学符合4次方模型G^4-G0^4=k0texp(-1 000Q/RT),晶粒生长速率常数k0=78.76μm4/h,激活能Q=433.35 kJ/mol。Grain growth kinetics of the substoichiometric UO2-x fuel pellets were studied with constant heating speed and isothermal sintering experiments. Substoichiometric UO2-x fuel pellets can be fabricated with qualified density of 94.91%TD-96.23%TD(TD is theory density) and O and U atomic ratio of 1.975-1.990 when the mixed powders of UO2+x and 5%U are sintered. Grain growth rate is very low when sintering temperature is below 1 650 ℃, but higher above 1 750 ℃. It is found that the starting grain size G0 cannot be neglected and the grain growth kinetics equation of the substoichiometric UO2-x fuel pellets is G^4-G0^4=k0texp(-1 000Q/RT), resulting in grain growth feature exponent n=4, rate constant k0=78.76 μm4/h and activation energy Q=433.35 kJ/mol.

关 键 词：二氧化铀 晶粒尺寸 晶粒生长动力学 激活能 亚化学计量 

分 类 号：TL352.21[核科学技术—核技术及应用]