摘要
研究了粒径组成对UO_(2)粉末流动性能、成型性能和UO_(2)芯块气孔分布及晶粒尺寸的影响;通过对不同粒径及不同粒径组成的UO_(2)粉末流动性及成型性进行研究,并用上述粉末制成UO_(2)生坯芯块及烧结芯块,并对其密度、气孔分布及晶粒尺寸进行研究。研究表明:二氧化铀粒径越小的粉末其松装、振实密度越小,流动性越差;对于不同粒径配比的粉末,当粉末中存在粒径<0.154 mm的粉末时,粉末流动性变差;用不同粒径配比的粉末制备出一批生坯,生坯密度随着小粒径粉末的加入先下降后提高,粒径<0.154 mm的细粉有利于提高生坯密度,生坯密度随细粉添加量的增大而增大;将生坯烧结成芯块以后,芯块密度与生坯密度呈正相关关系,粒径<0.154 mm的细粉有利于提高芯块密度;随着制备粉末中细粉的增加,芯块气孔率由小变大,细粉的加入几乎不影响0~2μm的气孔率,而>2μm的气孔率随着细粉的加入呈上升趋势;晶粒尺寸随着制备粉末中细粉含量增多而减小,气孔在晶界钉扎阻碍了晶粒长大。
The fluidity and formability of Uranium dioxide powders with different particle size and their composition were studied.The raw billets and tittered blocks of nuclear fuel were prepared by the powders,and the density and microstructure of the powders were studied.The smaller the particle size was,the smaller the vibration density was and the worse the fluidity was.For the powder with different particle size ratio,when the powder with particle size<0.154 mm,the fluidity of the powder rapidly became worse.The greens was prepared by these powders,and the density of greens increased at the first,then it decreased with addition of thin powder,the powder with size less than 0.154 mm increased the density.The pellets were prepared by these greens,the density of the greens and pellets were positively correlated relationship,the thin powders was beneficial to increase the density of pellets.The porosity of pellets increased with the addition of thin powders.The porosity of 0~2μm were hardly effected by the addition of thin powders,while the porosity of>0.2μm showed an upward trend with the addition of thin powders.The influence of small particles on porosity was explained by Rheins sintering model.The grain size decreased with the increase of then powder content in the prepared powder because the pores were nailed at grain boundaries.
作者
刘聪
李庆
陈煜
LIU Cong;LI Qing;CHEN Yu(CNNC China Nuclear Fuel Components Co.,Ltd.,Yibin 644000,China)
出处
《山东化工》
2025年第6期33-35,39,共4页
Shandong Chemical Industry
关键词
粒径组成
二氧化铀
粉末性能
芯块性能
particle size composition
uranium dioxide
powder properties
pellet properties
