一氮化铀质量热容的第一性原理计算  

Ab Initio Calculation of the Massic Heat Capacity of Uranium Mononitride

作　　者：王立鹏 姜夺玉 张信一 吴宏春[1] 樊慧庆[3] WANG Li-peng;JIANG Duo-yu;ZHANG Xin-yi;WU Hong-chun;FAN Hui-qing(School of Nuclear Science and Technology,Xi’an Jiaotong University,Xi’an 710049,China;Northwest Institute of Nuclear Technology,Xi’an 710024,China;School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西安交通大学核科学与技术学院,西安710049 [2]西北核技术研究院,西安710024 [3]西北工业大学材料学院,西安710072

出　　处：《现代应用物理》2020年第1期82-85,共4页Modern Applied Physics

基　　金：国家自然科学基金资助项目(11905174)。

摘　　要：基于第一性原理,采用VASP/PHONON软件模拟计算了0~3000 K下一氮化铀的质量热容,并对质量热容的构成进行了分析。结果表明,晶格振动质量热容是构成质量定容热容的基础,膨胀质量热容、电子质量热容和点缺陷质量热容是对质量定压热容额外的贡献,并且随着温度的升高,膨胀质量热容、电子质量热容和点缺陷质量热容均近似线性增加;质量定压热容在300~1500 K下与文献中的实验值符合较好,但在1500 K以上,由于引入点缺陷质量热容,造成计算结果与文献中的实验值偏差较大。Uranium mononitride(UN)is designated as a promising reactor fuel material for space nuclear power system and fast advanced reactors because of its good thermodynamics and neutronic parameters.The massic heat capacity of UN is estimated by ab initio calculation with VASP/PHONON code among the temperature of 03000 K,and the composition of the massic heat capacity of UN is analyzed.The results show that lattice vibration massic heat capacity is the basis for the massic heat capacity at constant volume.The expansion massic heat capacity,electron massic heat capacity,and Frenkel defect massic heat capacity are the extra contributions to the massic heat capacity at constant pressure,and they increased almost linearly with the temperature increasing.The massic heat capacity at constant pressure is in good agreement with the experimental value at 3001500 K,while the deviation between the calculated result and the experimental value is larger because of the Frenkel defect massic heat capacity introduced in temperature above 1500 K.

关 键 词：一氮化铀(UN) 质量热容 第一性原理 

分 类 号：TL271[核科学技术—核燃料循环与材料]