The grain structure of the silicon carbide (SiC) layer in tristructural-isotropic (TRISO) fuels has commonly been qualified in fuel specifications based on a qualitative comparison to visual standards to ensure undesirable microstructure are not produced. This approach is inherently dependent on subjective judgement and provides limited data for analysis or comparison. An alternative method to rapidly quantify (i.e., provide a numeric measure of) the grain structure of the SiC layer in TRISO fuels has been developed. This method relies on the identification of silicon carbide grain boundaries based on brightness variation in backscattered electron (BSE) images through the application of automated image processing algorithms. The speed with which the requisite BSE imaging and analysis may be completed enables the practical use of this method on an industrial scale as a part of qualifying TRISO fuel to meet a given specification on silicon carbide grain structure, which is an important parameter for TRISO fuel performance. The method is benchmarked by comparison to prior Electron-Backscattered Diffraction (EBSD) results for TRISO particles from the Advanced Gas Reactor (AGR) program.

基于与视觉标准的定性比较，三结构各向同性（TRISO）燃料中的碳化硅（SiC）层的晶粒结构通常已通过了燃料规格认证，以确保不会产生不良的微观结构。这种方法固有地依赖于主观判断，并且提供了有限的数据用于分析或比较。已经开发出另一种方法来快速量化（即提供数值测量）TRISO燃料中SiC层的晶粒结构。该方法依赖于基于反向散射电子（BSE）图像中亮度变化的碳化硅晶粒边界的识别，方法是应用自动图像处理算法。完成必要的BSE成像和分析所需的速度使得该方法可以作为TRISO合格燃料的一部分在工业规模上实际使用，以满足给定的碳化硅晶粒结构规范，这是TRISO燃料的重要参数性能。通过与先进气体反应器（AGR）程序中TRISO粒子的先前电子背散射衍射（EBSD）结果进行比较，对该方法进行了基准测试。