Preparation and Characterization of Large Grain UO2 for Accident Tolerant Fuel
Yi Zhong, Rui Gao, Bingqing Li, Zhenliang Yang, Qiqi Huang, Zhiyi Wang, Limei Duan, Xuxu Liu, Mingfu Chu, Pengcheng Zhang, Bin Bai, Yun Wang, Liang Cheng, Biaojie Yan, Tong Liu, Rui Li
Abstract
Large grain UO 2 is considered as an accident tolerant fuel with great application potential due to its competitive advantage of good fission gas retention. In this paper, the influence of preparation parameters such as sintering atmosphere, mixing process, powder pretreatment and grain growth additives on the grain size of UO 2 is systematically studied. The result shows that the factors mentioned above have different effects on the grain size of UO 2 . The grain growth of UO 2 pellet sintered in oxidizing atmosphere is better than those in reducing atmosphere. The wet mixing process has a significant advantage over the dry mixing process. In addition, the powder pretreatment has little effect on grain growth while the influence of additives plays the main role. Large grain UO 2 pellets with uniform grain size up to 150 μm are successfully prepared. Finally, the thermo-physical properties of the pellets are investigated.