耐事故核燃料UN抗氧化机制与性能增强的研究进展  

Research progress and development trends in the anti-oxidation mechanism and performance enhancement of uranium nitride as an accident-resistant nuclear fuel

作　　者：张钰 赵旭文 张玉娟[1] 杨宇 吕文婷 刘晓光[1] 褚明福[3] 杨振亮 许靖堃 葛昌纯[1] ZHANG Yu;ZHAO Xuwen;ZHANG Yujuan;YANG Yu;LÜWenti;LIU Xiaoguang;CHU Mingfu;YANG Zhenliang;XU Jingkun;GE Changchun(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Institute of Applied Physics and Computational Mathematics,Beijing 100088,China;Institute of Materials Research,China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]北京应用物理与计算数学研究所,北京100088 [3]中国工程物理研究院材料研究所,绵阳621900

出　　处：《工程科学学报》2025年第4期682-696,共15页Chinese Journal of Engineering

基　　金：国家自然基金资助面上项目(52371091);2024年度科技智库青年人才计划资助项目(XMSB20240710064);2024年度人工智能赋能研究生教育探索项目(2024JGAI06)。

摘　　要：氮化铀具有高铀密度、高热导率和高熔点等优点,被认为是最有潜力的耐事故核燃料之一.尽管氮化铀在核能安全等方面展现出极高的应用价值,但高温抗氧化性能和腐蚀性能不佳是其作为候选耐事故核燃料亟需解决的问题.针对氮化铀基核燃料在堆内服役条件下的低抗氧化性能,本文总结了氮化铀在空气中的氧化反应过程和提升氮化铀核燃料抗氧化性能的方法,具体包括采用高耐腐蚀陶瓷烧结形成保护屏障、添加合适的金属元素合金化、表面涂层技术等方法.重点讨论了氮化铀与各种陶瓷抗氧化相包括二氧化铀,二硅化三铀和其他陶瓷抗氧化相烧结形成复合燃料的抗氧化性能.其中,氮化铀-二氧化铀型复合燃料相比于氮化铀在高温和高压蒸汽环境下具有更高的氧化起始温度,显示出较高的抗氧化性能.因此重点探索了氮化铀-二氧化铀型复合燃料成分和微观结构对抗氧化性能影响的微观机制以及改进措施.三氮化二铀相的生成在提高氮化铀-二氧化铀抗氧化性能方面起到关键作用,但其高温稳定性仍存在争议.另外,本文还归纳了当前氮化铀基新型燃料在抗氧化性能提升研究方面亟需解决的科学问题.The Fukushima accident in 2011 prompted significant efforts to develop accident-tolerant fuel(ATF).The U.S.Department of Energy defines ATF as a fuel that can withstand a longer reactor core cooling loss time than the standard fuel system(UO_(2)-Zr)in the event of an accident.These advanced fuels must maintain their thermodynamic and mechanical stability under extreme conditions to prevent or mitigate accidents.Various new nuclear fuels and claddings have been proposed and developed.Among the many ATF candidates to replace traditional UO_(2) nuclear fuel,uranium nitride(UN)stands out owing to its high uranium density,thermal conductivity,and melting point,making it one of the most promising accident-resistant nuclear fuels.Despite its significant potential in enhancing nuclear safety and its applicability in various other fields,poor high-temperature oxidation and corrosion resistance remain urgent challenges for the UN as a candidate accident-resistant nuclear fuel.Given the low oxidation resistance of uranium nitride-based nuclear fuel under in-pile service conditions,this paper first discusses the oxidation process and mechanism of UN.The oxidation products of UN may vary depending on the experimental conditions,but they typically include UO_(2),U2N3,U3O8,and UO_(3).It was observed that UN is highly prone to oxidation,with an initial oxidation temperature of 200℃leading to the formation of oxynitride and U_(2)N_(3).At 250℃,the oxidation rate accelerates,nitrogen is released,and U_(3)O_(8) is eventually formed at 400℃.The calculation of the oxidation reaction of UN indicates that its oxidation is thermodynamically favorable and can occur even at low oxygen partial pressures,further demonstrating that UN readily reacts with oxygen in air.Oxidized UN typically exhibits a“sandwich”microstructure with an outer UO_(2) layer,an intermediate U_(2)N_(3) layer,and an inner UN layer.The results of oxidation experiments on UN single crystals suggest that the oxidation process involves the inward diffusion of oxy

关 键 词：耐事故燃料 氮化铀 抗氧化性能 二氧化铀 三氮化二铀 

分 类 号：TL211[核科学技术—核燃料循环与材料]