DEVELOPMENT OF ACTINIDE-HYDRIDE FUEL

氢化物燃料多年来一直用于研究反应堆(如TRIGA反应堆)。近年来，人们提出了一种利用榄系元素氢化物对核废料进行变质处理的方法。建立这一想法的最重要的研发项目之一是开发能够安全地照射到高燃速的榄系氢化物靶材。在本研究中，由于氢化物的氢化学势与Np和Am氢化物的氢化学势相近，所以使用了U-Th-Zr-H型靶材。用Sieverts装置成功地制备了无大裂纹的U-Th-Zr-H芯块。扫描电子显微镜(SEM)和X射线衍射仪(X射线衍射仪)分析表明，所制备的氢化物靶材主要由榄系金属相、榄系氢化物相和锆氢化物相组成。氢化物靶材的热导率数据是设计氢化物燃料销所必需的。用激光闪光法测量了U-Th-Zr-H型靶材的热扩散率。根据测量的热扩散率、密度的文献数据和比热之间的关系计算了导热系数。建立了导热系数随温度和氢含量变化的设计关联式。

Hydride fuels have been used in research reactors (e.g., TRIGA reactors) for many years. Recently, the transmutation method of nuclear wastes using actinide hydrides has been proposed. One of the most important R＆D items to establish the idea is the development of actinide-hydrides target, which can be safely irradiated up to high burnups. In this study, the U-Th-Zr-H type target material was used, since the hydrogen chemical potential of the hydride is close to that of Np and Am hydrides. The U-Th-Zr-H pellet have been successfully fabricated without large crack by means of a Sieverts apparatus. The scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses show that the hydride targets consist of actinide metal phase, actinide hydride phase and Zr hydride phase. Thermal conductivity data of actinide-hydrides targets are necessary for the design of the hydride fuel pin. The thermal diffusivity measurements of the U-Th-Zr-H type target material have been performed by means of a laser-flash method. The thermal conductivity was calculated from the relation of the measured thermal diffusivity, the literature data of the density, and the specific heat. The design correlation of the thermal conductivity has been developed as a function of temperature and hydrogen content.