摘要
钍基熔盐堆(Thorium Molten Salt Reactor,TMSR)是第四代核反应堆的代表之一,其特点是以熔融氟盐作为冷却剂和燃料的载体。在熔盐堆中,熔盐容易浸渗到核石墨内部,引发核石墨局部高温,造成核石墨损伤程度增加,严重破坏核石墨的结构,从而影响核石墨材料的宏观性能和使用寿命。然而,熔盐浸渗对核石墨力学性能的微观机制以及熔盐浸渗引起的微结构损伤或破坏机制目前仍不清晰,因此有待进一步研究原位环境下(如力学加载、高温等)熔盐浸渗对核石墨微结构的影响,并揭示微结构演化的相关机制。本文基于同步辐射原位拉伸X射线衍射技术(Two Dimensional X-ray Diffraction,2D-XRD),开展了外部载荷为0 N、15 N、21 N、27 N和32 N时熔盐浸渗后的核石墨IG-110在拉伸断裂过程中的微观结构演化研究,以揭示外部载荷条件下的核石墨IG-110与熔盐之间的原位实时相互作用及材料断裂的微观机制。实验结果表明:在拉伸断裂过程中外部载荷使熔盐浸渗后的核石墨IG-110的结晶性变差、层间距变大,同时FLiNaK盐的结晶性也明显变差。这一发现将有助于解释熔盐浸渗后核石墨IG-110力学性能的变化,理解核石墨IG-110与FLiNaK熔盐间的相互作用机理,有利于高性能核石墨的制备和TMSR的安全可靠运行分析。
[Background] Nuclear graphite is easily impregnated by liquid molten salt under high pressure environment due to its porous structure, which will affect the mechanical properties of the nuclear graphite. In-situ real-time tensile synchrotron-based two dimensional X-ray diffraction (2D-XRD) plays an important role in exploring the interaction between graphite and molten salt.[Purpose] This study aims to reveal the in-situ real-time interaction mechanism between IG-110 nuclear graphite and FLiNaK molten salt and the microscopic mechanism of material fracture under the external stress load.[Methods] In-situ real-time tensile synchrotron-based 2D-XRD at several fixed external forces, i.e., 0N, 15N, 21N, 27N and 32N, were implemented to reveal the microstructure evolution of IG-110 nuclear graphite and FLiNaK salt during the tensile fracture process.[Results] During the tensile fracture process, the (002) diffraction peak of IG-110 nuclear graphite infiltrated with molten salt presents an obvious shift to a lower q, a gradually decreasing peak intensity and a gradually increasing full width at half maximum (FWHM). Meanwhile, the diffraction peaks of the FLiNaK salt also present a gradually decreasing peak intensity.[Conclusion] In the process of tensile fracture, the larger the interlayer spacing, the worse the crystallinity of IG-110 nuclear graphite and FLiNaK salt are emerged.
作者
王佳敏
冯尚蕾
杨迎国
王勇
刘向东
周兴泰
WANG Jiamin;FENG Shanglei;YANG Yingguo;WANG Yong;LIU Xiangdong;ZHOU Xingtai(School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China;Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China)
出处
《核技术》
CAS
CSCD
北大核心
2019年第4期32-38,共7页
Nuclear Techniques
基金
国家自然科学基金(No.11705271
No.U1632268
No.11605278
No.11775134
No.11375108)
上海市扬帆计划(No.17YF1423700)
中国科学院战略性先导科技专项(No.XDA02040200)
山东省基金(No.ZR2016CM02)资助~~
关键词
钍基熔盐堆
核石墨IG-110
熔盐浸渗
同步辐射原位拉伸X射线衍射
Thorium molten salt reactor
IG-110 nuclear graphite
Molten salt impregnation
In-situ tensile synchrotron- based two dimensional X-ray diffraction
