Study of Pore Modality of Irradiated UO2 Fuel Assembly
UO2 fuel pellets may be swelling and recrystallization during irradiation.Density, dimension and distribution of pores are main factors to induce irradiation swelling, especially the size distribution of pellet pores plays an important role.4×4-4 fuel assembly was a high performance fuel assembly which was self-designed and manufactured, the average bum-up of the fuel assembly was 42GWd/tU.For studying the effect of irradiation on pore modality, the specimens of irradiated UO2 fuel pellets were taken from 4×4-4 fuel assembly after dismantling, microscopic structure and distribution of pores for UO2 fuel assembly by scanning electron microscopy were studied in this paper.The results showed that there were many cracks in fuel pellets, most micro-cracks were transgranular crack.The release rate of fission gas with bum up were augmentation, which was consistent with the porosity of diversity burp up fuel rod.Pores were distributed non-uniformly in irradiated fuel pellets, gathered at local area and more obvious connectivity of pores.The size of pores after the irradiation was between 0.2~1.2 μm, and mostly distributed at 0.3μm ~0.6 μm; The pores at grain boundary of two adjacent grains was less, the pores at grain boundary were distributed by the way of triangle or quadrilateral.The size of pores was increased than pre-irradiation, but ratio of pores and density of pores were decreased obviously, the phenomenon of irradiation densification was occurred in fuel pellets after irradiated.Recrystallization and Rim structure effect were not found.
Fuel pellets UO2 grains Fission gas Pore appearance Pore size Porosity
Yan-hua Peng Fei Wang Wei Zhu Yan Jiang Hong-kui Tang Bang Wen Guo-yun Li Juan Huang
Hot Laboratory, Nuclear Power Institute of China, Chengdu, P.R.CHINA
国际会议
The 2016 China Functional Materials Technology and Industry Forum (2016中国国际功能材料大会暨第九届中国功能材料及其应用学术会议)
重庆
英文
693-697
2016-07-25（万方平台首次上网日期，不代表论文的发表时间）