包覆燃料微球疏松热解碳层表观密度的测定  

Apparent density measurement of porous buffer layers of coated fuel microsphere

作　　者：王国华[1] 邓传东 郑娜 罗凤焱 贺含毅 曾强 赵峰[1] WANG Guohua;DENG Chuandong;ZHENG Na;LU Fengyan;HE Hanyi;ZENG Qiang;ZHAO Feng(National Key Laboratory for Nuclear Fuel and Materials,Nuclear Power Institute of China,Chengdu 610213,China)

机构地区：[1]中国核动力研究设计院反应堆燃料及材料重点实验室,成都610213

出　　处：《分析试验室》2025年第2期253-257,共5页Chinese Journal of Analysis Laboratory

基　　金：先进燃料技术研究项目(Z1019001)资助。

摘　　要：表观密度是影响燃料微球疏松热解碳包覆层抗辐照性能的关键参数之一。为测定以UO_(2)为核芯的燃料微球的疏松热解碳层密度,采用扫描电镜对包覆碳层的微结构进行了观察分析;通过高温氧化去除碳层,并分别利用同步热分析和X射线衍射等对碳层的氧化条件与包覆燃料微球的氧化产物进行了表征;在此基础上,通过称重-压汞法测定和计算疏松热解碳层的质量、体积和表观密度。结果表明,包覆层与UO_(2)核芯贴合紧密,燃料微球经温度高于816℃的空气氧化,碳包覆层被去除,核芯生成U_(3)O_(8),称重-压汞法的相对标准偏差小于2%(n=6)。该方法不依赖于燃料微球平均粒径和包覆层平均厚度的测量,适用于工程应用,为包覆燃料微球包覆碳层的表观密度测定提供了一种新方法。Apparent density is one of the key parameters related to the anti-radiation performance of porous buffer layers of fuel microsphere.To determine the apparent density of porous buffer layers of coated fuel with UO_(2) as the core,the microstructure of the porous buffer layers was observed by scanning electron microscope.The porous buffer layers were removed by air oxidation in high temperature.The oxidation conditions of layer and products of the coated fuel microspheres were characterized by synchronous thermal analysis and X-ray diffraction,respectively.The mass,volume,and apparent density of the porous buffer layers were measured and calculated with the weighing-mercury intrusion method.The results showed that the buffer layer was tightly adhered to the UO,core.The fuel microspheres were oxidized at temperature above 816 C to form U_(3)O_(8),and the carbon layers were removed.The relative standard deviation of the weighing-mercury intrusion method was less than 2%(n=6).This method does not rely on the measurement of the average particle size of fuel microspheres and the average thickness of buffer layers,and is suitable for engineering applications,providing a new method for determining the apparent density of the carbon layer of coated fuel microspheres.

关 键 词：包覆燃料微球 疏松热解碳层 表观密度 称重-压汞法 

分 类 号：TL27[核科学技术—核燃料循环与材料]