Abstract This study aims to provide microstructural characterization for the matrix graphite which molten salt reactors (MSRs) use, and improve resistance to molten salt infiltration of the matrix graphite for fuel elements. M esocarbon microbeads (MCMB) d ensified matrix g raphite A3-3 ( MDG ) was prepared by a quasi-isostatic pressure process. After densification by MCMBs with average particle sizes of 2, 10, and 16 μm, the pore diameter of A3-3 decreased from 924 nm to 484 nm, 532 nm, and 778 nm, respectively. Through scanning electron microscopy, the cross-section energy spectrum and time-of-flight secondary ion mass spectrometry, resistance levels of the matrix graphite to molten salt infiltration were analyzed. The results demonstrate that adding a certain proportion of MCMB powders can improve the anti-infiltration ability of A3-3. Meanwhile, the closer the particle size of MCMB is to the pore diameter of A3-3, the smaller the average pore diameter of MDG and the greater the densification. As a matrix graphite of fuel elements in MSR was involved, the thermal and mechanical properties of matrix graphite MDG were also studied. When densified by the MCMB matrix graphite, MDGs can meet the molten salt anti-infiltration requirements for MSR operation.

中文翻译：

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用于熔盐反应堆燃料元件的中间相碳微珠致密基体石墨 A3-3

摘要 本研究旨在为熔盐反应堆（MSR）使用的基体石墨提供微观结构表征，并提高用于燃料元件的基体石墨对熔盐渗透的抵抗力。采用准等静压法制备了中碳相微珠（MCMB）致密基体石墨A3-3（MDG）。通过平均粒径为 2、10 和 16 μm 的 MCMB 致密化后，A3-3 的孔径分别从 924 nm 减小到 484 nm、532 nm 和 778 nm。通过扫描电子显微镜、截面能谱和飞行时间二次离子质谱分析，分析了基体石墨对熔盐渗透的抵抗力水平。结果表明，加入一定比例的MCMB粉体可以提高A3-3的抗渗透能力。同时，MCMB的粒径越接近A3-3的孔径，MDG的平均孔径越小，致密化程度越大。由于涉及MSR中燃料元件的基体石墨，还研究了基体石墨MDG的热力学和机械性能。当通过 MCMB 基体石墨致密化时，MDGs 可以满足 MSR 运行的熔盐抗渗透要求。