测定石墨择优取向程度

Determination of the Degree of Preferred Orientation of Graphite

石墨广泛地用做核反应堆慢化材料、反射层材料和堆芯结构材料,在高温气冷堆中还用来做燃料元件。石墨材料的择优取向程度,对于它在反应堆中安全使用是一个重要的性能参数。有两种测定石墨择优取向程度方法。一种方法是用X射线衍射技术测极图,得到培根各向异性因子BAF;另一种方法是依据石墨晶体对可见光的双反射现象,得到表征石墨择优取向程度的另一参数一光学各向异性因子OPTAF。本文描述了用 D/max—3B型X射线衍射仪测定BAP的实验过程,给出了测量结果,讨论了两种方法各自的优缺点。本文得出结论:对于热解石墨样品,用本文所述测量方法得到的BAF和OPTAF是等同的。

In the nuclear reactor field,graphite was used widely as the moderators,the reflectors, the constructive materials of reactor core and the fuel elements in High Temperature Gascooled Reactor. The degree of preferred orientation of graphite materials is a important property for its safety use in nuclear reactor. Two methods have been used to determine the graphite's degree of preferred orientation, the one is determination of pole figure by X-ray diffraction technology to obtain the Bacon Anisotropy Factor-BAF, the another si to determine the Optical Anisotropic Factor-OPTAF according to the bireflectory phenomenon to visible light by graphite crystal. In this paper, the experiment procedure was described to determine the BAF by X-ray diffractor model D/max-3B. For the two methods,the measurement results were given and the advantages and disadvantages were discussed. It is concludid that the BAF and OPTAF respectively by the two methods for the pyrolytic graphite samples are identical.