高温^(107)Ag^(5+)离子辐照后核石墨的截面微区拉曼表征与缺陷演化规律研究  

Exploring the defects evolution of nuclear graphite by using micro-Raman characterization on the cross-section of ^(107)Ag^(5+)ion irradiated nuclear graphite at high temperature

作　　者：李一言 贺周同[2] 赵修良[1] 彭善成 马慧磊 LI Yiyan;HE Zhoutong;ZHAO Xiuliang;PENG Shancheng;MA Huilei(School of Nuclear Science and Technology,University of South China,Hengyang 421001,China;Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]中国科学院上海应用物理研究所,上海201800 [3]中国科学院大学,北京100049

出　　处：《核技术》2024年第4期39-50,共12页Nuclear Techniques

基　　金：上海市自然科学基金(No.19ZR1468100)资助。

摘　　要：在第四代反应堆中,核石墨作为慢化体和反射体材料服役于高温和高通量的快中子辐照环境中。快中子辐照会在核石墨中产生大量的弗伦克尔缺陷对。这些缺陷经过湮灭、扩散、最终形成更大的缺陷团簇,从而改变核石墨的微观结构,进而改变核石墨的宏观性能。因此,研究核石墨在高温辐照条件下的缺陷演化行为和机理对提高反应堆安全性具有重要意义。本研究采用30 MeV的^(107)Ag^(5+)离子在420℃下辐照IG-110核石墨来模拟核石墨在快中子辐照过程中的缺陷演化行为。通过微区拉曼光谱对IG-110核石墨截面结构进行表征,并对比不同深度处的拉曼光谱特征参数和辐照损伤剂量之间的关系,研究IG-110核石墨微观结构随辐照损伤剂量(Displacements Per Atom,DPA)的演化行为。研究结果表明,随着注量的增加,核石墨拉曼光谱的特征参数D峰高度与G峰高度比值(I_(D)/I_(G))、G峰半高宽(Full Width at Half Maximum of the G peak,FWHM(G))以及G峰的偏移量都显著增加。与^(58)Ni^(5+)辐照样品相比,相同辐照损伤剂量下,^(107)Ag^(5+)辐照的石墨拉曼光谱的I_(D)/I_(G)和FWHM(G)更大。相同的FWHM(G)下,^(107)Ag^(5+)辐照的石墨拉曼光谱的I_(D)/I_(G)比^(58)Ni^(5+)辐照样品大。这些结果说明更重的重离子辐照会在核石墨中引起更高速率的缺陷积累,从而更快地导致石墨晶粒尺寸变小,并促进纳米晶化进程。[Background]Within GEN-IV reactors,nuclear graphite plays a crucial role as both a moderator and reflector in an environment characterized by high temperatures and intense fast neutron irradiation.The exposure to fast neutron irradiation induces the formation of numerous Frankel defects in the nuclear graphite.These defects undergo processes of annihilation and diffusion,ultimately giving rise to larger defect clusters.This transformation in the microstructure of nuclear graphite directly impacts its macroscopic properties,necessitating a thorough investigation.[Purpose]This study aims to comprehensively explore the evolution of defects in nuclear graphite under conditions of high-temperature irradiation which is essential for advancing reactor safety.[Methods]Firstly,the 30 MeV ^(107)Ag^(5+)ion source was employe to irradiate IG-110 nuclear graphite at 420℃,simulating the defect evolution behavior during fast neutron irradiation of nuclear graphite.Then,the energy loss,defect distribution,and ion implantation profiles of 30 MeV ^(58)Ni^(5+)and ^(107)Ag^(5+)ion beams bombarding standard nuclear graphite ICRU-906(density of 2.26 g∙cm-3,displacement energy of 28 eV)were calculated using the full cascade damage model in the SRIM(Stopping and Range of Ions in Matter)software.The cross-sectional structure of IG-110 nuclear graphite was characterized using micro-Raman spectroscopy.Finally,the relationship between the Raman spectroscopic features at various depths of IG-110 nuclear graphite and the irradiation damage dose was compared to investigate the evolution of IG-110 nuclear graphite microstructure with increasing irradiation damage dose(Displacements Per Atom,DPA).[Results]With the increase in particle fluence,the characteristic parameters of the Raman spectra of nuclear graphite,including the I_(D)/I_(G) ratio(the ratio of the D peak height to the G peak height),the Full Width at Half Maximum of the G peak(FWHM(G)),and the shift of the G peak,all show significant increments.Compared to samples irradiated wit

关 键 词：重离子辐照 IG-110核石墨 微区拉曼光谱 缺陷演化规律 高温辐照 截面拉曼成像 

分 类 号：TL99[核科学技术—核技术及应用]