新型钍基类MOX燃料的制备和第一性原理研究  

Preparation and First-principles Study of New Thorium-based MOX Fuel

作　　者：赵石 魏强林[1,2,3] 刘义保 刘豪杰[2] 李凯旋 ZHAO Shi;WEI Qianglin;LIU Yibao;LIU Haojie;LI Kaixuan(Engineering Research Center of Nuclear Technology Application,Ministry of Education,East China University of Technology,Nanchang 330013,China;School of Nuclear Science and Engineering,East China University of Technology,Nanchang 330013,China;Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation,East China University of Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学核技术应用教育部工程研究中心,江西南昌330013 [2]东华理工大学核科学与工程学院,江西南昌330013 [3]东华理工大学江西省质谱科学与仪器重点实验室,江西南昌330013

出　　处：《原子能科学技术》2024年第10期2189-2197,共9页Atomic Energy Science and Technology

基　　金：核技术应用教育部工程研究中心开放基金(HJSJYB2021-9);东华理工大学博士启动基金(DHBK2021005);江西省质谱科学与仪器重点实验室开放基金(JXMS202111)。

摘　　要：为研究钍基类MOX(Th-MOX)燃料Th_(1-x)Pu_(x)O_(2)的结构及性质,以性质相近的Ce原子替代Pu原子,采用溶胶-凝胶法在不同烧结温度下制备了Th_(1-x)Ce_(x)O_(2)(x=0,0.25,0.50,0.75,1),利用XRD、SEM和拉曼光谱仪对其形貌和结构进行了表征,同时采用基于密度泛函理论的第一性原理计算软件VASP计算了Th_(1-x)Ce_(x)O_(2)的晶格常数和电子态密度。实验结果表明:制备得到的Th_(1-x)Ce_(x)O_(2)在致密性和颗粒均匀性方面表现出良好的性能。随烧结温度的升高,密度先增大后减小(最高达到理论密度的98.4%),晶界迁移使晶粒尺寸增大。混合氧化物在形成的过程中晶格中产生了氧缺位,随着体系中Th含量的增加,晶粒尺寸减小、能量带隙增大、导带宽度减小,Th原子的局域态密度增大,Ce原子的局域态密度减小,原子半径的差异导致晶格常数、Th—O键和Ce—O键的平均键长增大,Th_(1-x)Ce_(x)O_(2)晶格常数的计算值与实验值吻合良好。The development of thorium-based nuclear fuel is of significance for the long-term sustainable development of nuclear power.Among these,Th_(1-x)Pu_(x)O_(2) stands as a highly promising nuclear fuel with proven applications in various reactor types.This study aims to explore the structural and qualitative characteristics of thorium-based mixed oxide (Th-MOX) fuel Th_(1-x)Pu_(x)O_(2).With the substitution of Ce for Pu,the sol-gel method was employed to synthesize Th_(1-x)Ce_(x)O_(2) (x=0,0.25,0.500.75,1) at varying sintering temperatures (800,1 000,1 200,1 400,1 600℃).The morphology and structure of Th_(1-x)Ce_(x)O_(2) were characterized by X-ray diffractometer (XRD),scanning electron microscope (SEM) and Raman spectrometer.The lattice constant and electronic density of state (DOS)of Th_(1-x)Ce_(x)O_(2) were calculated using the first-principles calculation software VASP based on density functional theory.The experimental findings demonstrate that the prepared Th_(1-x)Ce_(x)O_(2) material exhibits excellent properties in terms of density and particle uniformity.With the increase in sintering temperature,the results of density testing indicate that the material’s density exhibits a trend of initially increasing and then decreasing,ultimately reaching a maximum of 98.4%of the theoretical density This phenomenon occurs due to as the sintering temperature increases,the diffusion process induces the migration of grain boundaries,enlarging the contact area between grains and reducing the presence of pores,thereby increasing the material density.However,further elevating the sintering temperature results in the formation of a liquid phase on the material surface,impeding the migration of grain boundaries.This leads to an expansion of gaps between particles,an increase in the number of pores and ultimately a reduction in density.The XRD analysis reveals that variations in sintering temperature have a negligible effect on the lattice constant of Th_(1-x)Ce_(x)O_(2).Nevertheless,the grain size demonstrates a trend of ini

关 键 词：钍基类MOX燃料 溶胶-凝胶法 第一性原理 态密度 

分 类 号：TL272[核科学技术—核燃料循环与材料]