U_(3)O_(8)-ZrN弥散型核燃料热导率的模拟与实验研究  

Simulation and experimental study on thermal conductivity of U_(3)O_(8)-ZrN dispersed nuclear fuel

作　　者：彭韬 李朝 舒瀚东 常振旗[1] PENG Tao;LI Chao;SHU Han-dong;CHANG Zhen-qi(Department of Nuclear Science and Engineering,University of Science and Technology of China,Hefei 230026,Anhui Province,China)

机构地区：[1]中国科学技术大学核科学与工程系,安徽合肥230026

出　　处：《化学工程》2022年第7期6-10,共5页Chemical Engineering(China)

基　　金：国家自然科学基金面上项目(21978279);安徽省重点研究与开发计划(201904a05020048)。

摘　　要：弥散型核燃料是先进核燃料的重要燃料类型。文中以溶胶凝胶法结合微流控技术实现单分散性U_(3)O_(8)核燃料微球(粒径分布CV<5%)的制备,采用模压成形、无压烧结法制备了不同U_(3)O_(8)微球体积分数的U_(3)O_(8)-ZrN弥散型核燃料芯块,并对其在不同温度下的热导率进行了模拟计算与实验研究。研究结果表明:相比于氧化铀燃料芯块,由氧化铀微球弥散在氮化锆基体中构成的弥散核燃料芯块的热导率显著提高,并随着温度的升高而增大,呈现出与温度的正相关性,这一特性有助于极高温环境中(事故状态)燃料芯块温度梯度的减小,提高燃料芯块高温下的安全性。增加U_(3)O_(8)-ZrN弥散型核燃料芯块中ZrN弥散介质体积分数可以快速提高芯块热导率,但导致芯块中燃料相含量的降低。Dispersed nuclear fuel is an important type of advanced nuclear fuel.Monodisperse U_(3)O_(8) nuclear fuel microspheres with size distribution CV<5%were prepared by a sol-gel process combined with microfluidic technology,and a number of U_(3)O_(8)-ZrN dispersed nuclear fuel pellets with different volume fractions of U_(3)O_(8) microspheres were fabricated by compression molding and sintering processes.By means of experiments and finite element simulations,the thermal conductivity of the pellets were studied.The results show that compared with U_(3)O_(8)fuel pellets,the thermal conductivity of U_(3)O_(8)-ZrN dispersed nuclear fuel pellets is significantly improved and exhibits an opposite temperature dependence to that of U_(3)O_(8)fuel pellets,which increases with the increase of temperature,namely showing a positive correlation with temperature.This feature improves the safety of the fuel pellet by helping to reduce the temperature gradient of the fuel pellet in the extremely high temperature environment(accident state).Increasing the volume fraction of ZrN dispersed medium in U_(3)O_(8)-ZrN dispersed nuclear fuel pellets can rapidly increase the thermal conductivity of the pellets,but leads to a decrease in the content of fissile nuclide in the pellets.

关 键 词：弥散型核燃料 氧化铀 氮化锆 热导率 数值模拟 

分 类 号：TL352[核科学技术—核技术及应用]