压水堆完整和破损燃料棒燃料包壳化学相互作用层拉曼特征分析  

Raman Characteristics Analysis of Fuel-cladding Chemical Interaction Layer for Intact and Leak PWR Fuel Rods

作　　者：王华才[1] 程焕林 宋武林 郭丽娜[1] 汤琪[1] 郭一帆[1] 杨启法[1] WANG Huacai;CHENG Huanlin;SONG Wulin;GUO Lina;TANG Qi;GUO Yifan;YANG Qifa(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2023年第3期619-629,共11页Atomic Energy Science and Technology

基　　金：中核集团“青年英才”项目。

摘　　要：为研究压水堆完整和破损燃料棒燃料包壳化学相互作用(FCCI)层物相结构组成及影响因素,通过拉曼光谱对燃耗为45 GW·d/tU和41 GW·d/tU的完整和破损燃料棒FCCI层进行了研究分析。结果表明:完整燃料棒形成了周向厚度为14~19μm的FCCI层,主要由两个不同相结构区域组成,分别为靠近包壳界面的单斜和四方相氧化锆混合区域及靠近燃料芯块的四方相区域,在包壳界面附近约7μm范围内,观察到明显的705 cm^(-1)特征峰,该峰的形成源于界面压应力和辐照缺陷的共同作用;破损燃料棒形成了周向厚度为37~61μm的FCCI层,主要由两个不同形貌和相结构区域组成,即靠近包壳界面附近具有多孔、裂纹特征的单斜相氧化锆区域以及靠近燃料芯块的非晶结构区域。对FCCI层相结构的分布及转变影响因素进行了分析讨论,完整燃料棒FCCI层中四方相氧化锆的稳定与界面压应力、中子辐照缺陷和裂变产物作用有关,破损燃料棒FCCI层中单斜相氧化锆的存在则主要来源于应力的弛豫和氧的正常化学计量比。Zirconium alloys have long been used as cladding materials for pressurized water reactors(PWR)due to excellent corrosion resistance and low thermal neutron capture cross-section.With the increasing of burnup,the chemical interaction layer has formed in the gap due to fuel-cladding chemical interaction(FCCI),which has an important influence on the thermal conductivity of fuel-cladding mechanical interaction(PCMI).In addition,if the fuel rods are leaked and the coolant enters the inner side of the cladding,the FCCI will be significantly intensified.The FCCI layer is affected by factors such as burnup,fuel rod leak,neutron irradiation,fission products,stress,temperature,etc.,the composition and distribution of FCCI layer phase structure are relatively complex.In recent years,with the development of Raman spectroscopy technology,Raman spectrometer has been applied to the study of radioactive materials(such as fuel pellets,oxide film).In this paper,in order to study phase structure composition and influencing factors of FCCI layer of intact and leaked fuel rods in PWR,the FCCI layers of intact and leak fuel rods with 45 GW·d/tU and 41 GW·d/tU burnup were analyzed by Raman spectroscopy.The results show that the FCCI layer with uniform circumferential thickness of 14-19μm is formed in the intact fuel rod,which is mainly composed of two different phase structure regions:the mixed phase region of monocline and teteal zirconia near the cladding interface.In the range of about 7μm near the cladding interface,an obvious 705 cm^(-1) spectral peak is observed,which reflects the influence of interface compressive stress and irradiation defects.The leak fuel rods forms a chemical interaction layer with circumferential thickness varying from 37μm to 61μm,which is mainly composed of two different morphologies and phase structures:the monoinclined zirconia region with porosity and crack which is near the cladding interface;the amorphous phase region which is near the fuel pellet.The distribution of phase structure of chemical

关 键 词：完整和破损燃料棒 FCCI层 氧化锆 拉曼光谱 

分 类 号：TL341[核科学技术—核技术及应用]