钨基氮化铀微球弥散燃料制备工艺及性能研究  

Study on Preparation Process and Performance of Tungsten-based Uranium Nitride Microspheres Dispersed Fuel

作　　者：刘文涛 杜江平[1,2] 赵雨梦 马春雨 刘伟 蔡振方 LIU Wentao;DU Jiangping;ZHAO Yumeng;MA Chunyu;LIU Wei;CAI Zhenfang(CNNC Key Laboratory of Fabrication Technology of Reactor Irradiation Special Elements,Baotou 014035,China;China North Nuclear Fuel 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,内蒙古包头014035 [2]中核北方核燃料元件有限公司,内蒙古包头014035

出　　处：《原子能科学技术》2024年第S01期96-103,共8页Atomic Energy Science and Technology

基　　金：中核集团“青年英才”项目。

摘　　要：金属陶瓷(CERMET)弥散燃料是目前核热推进反应堆用燃料研发热点。氮化铀(UN)微球具有高铀密度、高热导率、高填充率等特点,钨基体具有高熔点、高热导率及低线性热膨胀系数等优点,将两者结合形成的钨基氮化铀微球弥散燃料是空间核动力的理想候选材料。本文突破了碳热还原-氮化关键难点,成功制备了高纯UN微球,采用无压通氢烧结的工艺路线,实现了钨基UN弥散燃料芯块制备,研究了不同参数对UN微球和弥散燃料芯块性能的影响规律。结果表明,当碳化温度为1900℃、保温时间为8 h、氮化温度为1900℃、保温时间为3 h时,UN微球的纯度最高,达93.79%,相对密度为96%T.D.;以丙三醇为黏结剂、无水乙醇为稀释剂,对UN微球与基体钨粉进行湿混后直接装模压制,UN微球在钨基体中分布较均匀;使用氢气进行致密化烧结,在1900℃可获得95%T.D.以上致密度。对燃料芯块的性能测试表明,钨基UN芯块中的微球完整且分布均匀,微球中U、N原子比为1.04∶1,钨基体与UN微球界面粘附紧密,无分层;随着温度的升高,芯块的导热系数逐渐降低,100℃时的导热系数为182.6 W/(m·K)。CERMET dispersion fuel is currently a hotspot in the research and development of fuels for nuclear thermal propulsion(NTP)reactors.Uranium nitride(UN)has a uranium density 40%greater than that of uranium dioxide(UO2),as well as the advantages of high thermal conductivity and good resistance to irradiation.But the melting point of UN is relatively low compared to that of UO2,and it has a large linear coefficient of thermal expansion.If UN fuel is purely used,it will greatly limit the operating temperature of the reactor core,thus reducing the NTP specific impulse.Tungsten has the advantages of high melting point,high thermal conductivity,and low linear coefficient of thermal expansion,which can make up for the shortcomings in the thermal performance of UN fuel.Meanwhile,to further enhance the loading capacity of the dispersed fuel,the structure of the UN dispersed fuel is designed in the form of microspheres.The advantages of the two materials complement each other,so that tungsten-based UN microspheres dispersed fuel can be obtained,which is an ideal material for space NTP system.In this work,the preparation of UN microspheres as well as tungsten-based UN microsphere dispersed fuel pellets was successfully realized by adopting the process route of carbothermal reduction-nitriding,cold press molding,and pressureless hydrogen sintering.The effects of different parameters on the preparation effect of the UN microspheres and pellets were investigated,and the properties of the UN microspheres and pellets were also characterized and analyzed.It is found that the UN microspheres have the highest purity of 93.79%and the relative density of 96%T.D.,when the carbonization temperature is 1900℃and the holding time is 8 h,and the nitriding temperature is 1900℃and the holding time is 3 h.The wet mixing and drying of UN microspheres using propylene tritol as binder and anhydrous ethanol as diluent can make the distribution of UN microspheres in the pressed pellets more uniform;and the densification sintering using a hydroge

关 键 词：金属陶瓷燃料 氮化铀微球 钨基体 碳热还原-氮化 

分 类 号：TL352.2[核科学技术—核技术及应用]