事故容错燃料包壳候选材料的研究现状及展望  

A Complete Review and a Prospect on the Candidate Materials for Accident-tolerant Fuel Claddings

作　　者：刘俊凯 张新虎 恽迪 LIU Junkai;ZHANG Xinhu;YUN Di(School of Energy and Power Engineering,Xi＇an Jiaotong University,Xi＇an 710049;State Key Laboratory of Multi phase Flow in Power Engineering,Xi＇an Jiaotong University,Xi＇an 710049)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049 [2]西安交通大学动力工程多相流国家重点实验室,西安710049

出　　处：《材料导报》2018年第11期1757-1778,共22页Materials Reports

摘　　要：2011年福岛核电站事故中,反应堆堆芯燃料中的锆合金包壳在事故工况下与高温水蒸汽发生剧烈氧化反应继而产生大量的氢气和热量,最终导致反应堆堆芯熔化和氢气爆炸,对社会和环境造成极大负面影响。自此之后,国内外纷纷展开对事故容错燃料的研究开发。相较于传统的UO2-Zr合金燃料体系,事故容错燃料能够在反应堆正常运行工况下维持或提高燃料性能,并在事故发生后相当长的一段时间内维持堆芯完整性,提供足够的时间裕量来采取事故应对措施。反应堆堆芯环境非常极端,包壳长期处于高温高压腐蚀介质中,同时还受到中子辐照的影响,因此新型包壳材料需要较好的耐腐蚀性和辐照稳定性。经不同研究者的研究评估,目前能够替代Zr合金的事故容错燃料包壳材料可分为陶瓷材料和金属材料两类:陶瓷材料主要以SiC/SiC复合材料为代表;金属材料主要有以FeCrAl为代表的Fe基合金和以Mo为代表的难熔金属及其合金。上述三种替代Zr包壳的材料各有其利弊,均未达到工程应用水平,并且都存在待解决的关键性问题。其中,FeCrAl合金的研发进展最快,目前在热学性能、力学性能、抗腐蚀性能、抗辐照性能等方面表现较好,但在工业加工和焊接等方面仍有待进一步改善。就SiC/SiC复合材料而言,由于SiC自身的高脆性而导致力学强度不足,不同的研究者提出了不同的结构设计思路试图降低包壳管失效概率,但包壳最终的结构设计仍未确定,而辐照引起的热导率急剧降低及连接密封和加工制造等方面还在不断研究中。Mo及Mo合金的力学性能和抗辐照性能较好,但自身抗腐蚀性较差,解决思路主要集中在提高钼纯度、调整合金的元素成分、进行表面涂层等方面。目前,对后两种材料包壳管的加工能力均未达到薄壁长管的工业制造水平。对于这几种候选包壳材料,需要建立属性数In the 2011 Fukushima nuclear power plant accident,the zirconium alloy claddings in the reactor fuel were oxidized violently by high temperature water vapor generated under accident conditions,resulting in a large amount of hydrogen and heat,which eventually led to reactor core melt down and hydrogen explosion.The event delivered severe impacts on the human society and the environment.From then on,the development programs of accident-tolerant fuels（ATF）have been initiated worldwide.Compared with the traditional UO2-Zr system,ATF can sustain or improve the fuel performance at normal operating conditions,as well as maintain the core integrity for an extended time after accidents to provide temporal safety margins for the accident management.The environment of the reactor core is very harsh,as the claddings are exposed lastingly to high temperature and high pressure corrosion medium,and moreover,neutron irradiation.As a result,if any new materials were to qualify as cladding materials,they would need excellent radiation stability and corrosion resistance.According to the research and evaluation of different researchers,the accident-tolerant fuel cladding materials which has displayed the potential of substituting for Zr alloy can be classified into ceramic materials and metallic materials,in which the ceramic materials are mainly represented by SiC/SiC composite materials,and the metallic materials mainly include Fe-based alloy exemplified by FeCrAl and refractory metals exemplified by Mo/Mo alloy.Each of the three materials has its own advantages and disadvantages,and still needs improvements to attain the requirement of engineering application,and all of them have some unresolved key issues.The research and development of the FeCrAl alloy has reached the second generation model alloy.The thermophysical and mechanical properties,corrosion resistance and radiation resistance of FeCrAl alloy are outstanding,while the research on hydrogen permeability and industrial processing and welding are still in progress.In

关 键 词：事故容错燃料(ATF) 碳化硅 铁铬铝合金 钼合金 

分 类 号：TL352[核科学技术—核技术及应用]