Ce-Nd合金与不锈钢相互作用实验研究  

Experimental Study on Interaction between Ce-Nd Alloy and Stainless Steel

作　　者：阮章顺 张瑞莹 王宇回 涂蒙河 付晓刚[1] 龙斌[1] RUAN Zhangshun;ZHANG Ruiying;WANG Yuhui;TU Menghe;FU Xiaogang;LONG Bin(Department of Reactor Engineering Technology,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院反应堆工程技术研究所,北京102413

出　　处：《原子能科学技术》2025年第S1期159-164,共6页Atomic Energy Science and Technology

基　　金：中核集团集中研发项目。

摘　　要：对于一体化快堆采用的金属燃料,燃料包壳化学相互作用是限制其燃耗深度的关键因素,其中以Ce、Nd等为代表的裂变产物元素可能与包壳材料形成低熔点共晶,造成包壳失效。本研究采用自行设计的扩散偶装置开展了Ce-Nd合金与不锈钢、12Cr铁马钢和电镀Cr涂层材料在液态钠环境中的相互作用实验,对Ce、Ni元素与304基体中的Fe、Ni、Cr以及涂层Cr元素之间的相互扩散进行了研究,以了解燃料包壳化学相互作用的形态,并初步测试了防护涂层的作用。结果表明:电镀Cr涂层在550℃时可将Ce、Nd元素扩散层深度降低一半,但由于涂层存在缺陷,在650℃时无明显防护效果。In integrated fast reactor,metal fuel is used for its advantages in fuel reprocessing and recycling.However,under high temperature and irradiation,complex mechanical and chemical interactions between the fuel and cladding significantly limit fuel lifespan and burnup depth.The mechanical interactions are basically solved by responding designs:metal fuels swell at low burnup levels,exerting pressure on the cladding and causing deformation,which is addressed by designs include an initial gap filled with sodium to accommodate expansion and improve heat transfer.A fission gas plenum helps maintain low internal pressure,enabling higher burnup.Key chemical interaction includes the following categories.1)Intergranular corrosion:Fission products like Ce and Nd migrate to the cladding,weakening it through corrosion.2)Eutectic melting:U and Pu diffuse into the cladding while Fe and Ni migrate into the fuel,forming low-melting-point alloys near the interface.Eutectic points can be as low as 650℃for U-Pu-Fe systems.Lanthanides like Ce and Nd show similar phenomena.3)Decarburization:Carbon migrates from cladding to fuel,altering the cladding’s structure.However,this effect is less significant.To mitigate these issues,10%Zr was added to the fuel to raise its melting point.Protective coatings on cladding,such as Cr or Cr nitrided layers,were also used to suppress fuel-cladding chemical interactions(FCCI).Coating methods could be utilized for interior coating of claddings,including electroplating and metal-organic chemical vapor deposition(MOCVD).In this study,interactions between Ce-Nd alloys and cladding materials(304 stainless steel,12Cr ferritic/martensitic steel,and electroplated Cr-coated 304 SS)in sodium(Na)and argon(Ar)environments were tested at 550℃ and 650℃ for about 50 hours.SEM and EDS analyses were used to assess diffusion behavior.At 550℃,Cr-coated samples reduce FCCI diffusion depth by 50%compared to uncoated 304 SS.However,coating cracks allow limited Ce-Nd infiltration.At 650℃,severe diffusion occurs

关 键 词：金属燃料 燃料包壳化学相互作用 液态钠 扩散 

分 类 号：TL341[核科学技术—核技术及应用]