氧化石墨烯掺杂UO_(2)芯块制备工艺及性能研究  

Preparation process and performance of graphene oxide-doped UO_(2) pellets

作　　者：温丰 杜江平[1,2] 赵雨梦 杨宁 邵宗义 刘伟 蔡振方 WEN Feng;DU Jiangping;ZHAO Yumeng;YANG Ning;SHAO Zongyi;LIU Wei;CAI Zhenfang(CNNC Key Laboratory of Fabrication Technology of Reactor Irradiation Special Elements,Baotou 014035,China;China North Nuclear Fuel Element Co.,Ltd.,Baotou 014035,China)

机构地区：[1]中核反应堆辐照特种元件制备工艺重点实验室,包头014035 [2]中核北方核燃料元件有限公司,包头014035

出　　处：《核技术》2024年第6期168-176,共9页Nuclear Techniques

摘　　要：氧化石墨烯(Graphene Oxide,GO)掺杂改性二氧化铀(UO_(2))芯块是高性能核燃料研究的重点方向之一。为实现GO在UO_(2)芯块中的均匀分布及掺杂量的有效控制,利用固-液混合法和重铀酸铵(Ammonium Diuranate,ADU)共沉淀法制备了不同GO掺杂量的UO_(2)粉末,研究了制粉方法及GO掺杂量对GO在UO_(2)中混合均匀性的影响。采用放电等离子烧结制备了不同GO掺杂量的UO_(2)-GO芯块,探索了不同烧结参数的影响,并对燃料芯块的性能进行测试。结果表明,固-液混合法制备的GO掺杂UO_(2)粉末混合均匀度更好;放电等离子烧结得到的UO_(2)-GO芯块密度最高可达97.6%T.D.;GO掺杂量为1.5 wt.%的芯块在1000℃下的热导率较常规UO_(2)芯块提高了85.9%;制备的UO_(2)-GO芯块晶粒尺寸较为均匀,GO均匀分布在晶界处并形成了桥联导热网络,有效提升了掺杂芯块的热导率。[Background]Uranium dioxide(UO_(2))has been broadly employed as nuclear fuel in nuclear reactors.However,the poor thermal conductivity of UO_(2) compromises the safety of the reactor owing to possible sharp temperature gradients.Graphene oxide(GO)is a promising additive to improve the thermal conductivity of UO_(2) owing to its excellent thermal performance.[Purpose]This study aims to achieve uniform distribution of GO in UO_(2) pellets,effectively controlling the doping amounts to enhance the thermal conductivity of UO_(2) pellets.[Methods]GO-doped UO_(2) powders with different doping amounts were prepared using solid-liquid mixing and ammonium diuranate(ADU)co-precipitation methods.After establishing the optimized powdering process,UO_(2)-GO composite fuel pellets were prepared by spark plasma sintering(SPS).Properties of the UO_(2)-GO composite fuel pellets,such as density,grain size,physical phase,and thermal conductivity,were examined using scanning electron microscope(SEM),energy dispersion spectrometer(EDS),metallographic microscope,laser pulse thermal conductivity meter,etc.,and compared with those of conventional pure UO_(2) pellets.[Results]The results showed that the density of UO_(2)-GO pellets can reach up to 97.6%T.D..The thermal conductivity of UO_(2)-GO pellets with 1.5 wt.%doped GO is 85.9%higher than that of conventional UO_(2) pellets at 1000℃.The grain size of the UO_(2)-GO pellets is uniform,and the GO is homogeneously distributed at the grain boundary to form a bridging thermal conduction network.[Conclusions]The thermal conductivity of UO_(2) pellets is successfully improved through GO doping.

关 键 词：氧化石墨烯掺杂改性 UO_(2)芯块 固-液混合法 放电等离子烧结 热导率 

分 类 号：TL352.2[核科学技术—核技术及应用]