One of the promising candidates for accident-tolerant fuel (ATF), a ceramic microcell fuel, which can be distinguished by an unusual cell-like microstructure (UO2 grain cell surrounded by a doped oxide cell wall), is being developed. This study deals with the microstructural observation of the constituent phases and the wetting behaviors of the cell wall materials in three kinds of ceramic microcell UO2 pellets: Si-Ti-O (STO), Si-Cr-O (SCO), and Al-Si-Ti-O (ASTO). The chemical and physical states of the cell wall materials are estimated by HSC Chemistry and confirmed by experiment to be mixtures of Si-O and Ti-O for the STO; Si-O and Cr-O for SCO; and Si-O, Ti-O, and Al-Si-O for the ASTO. From their morphology at triple junctions, UO2 grains appear to be wet by the Si-O or Al-Si-O rather than other oxides, providing a benefit on the capture-ability of the ceramic microcell cell wall. The wetting behavior can be explained by the relationships between the interface energy and the contact angle.

Abstract
1. Introduction
2. Experimental
3. Results and Discussion
4. Conclusions
References

• 전상채(창원대학교 신소재공학부) | Sang-Chae Jeon (School of Materials Science and Engineering, Changwon National University) Corresponding Author
• 김동주(한국원자력연구원 ATF 기술개발부) | Dong-Joo Kim (ATF Technology Development Division, Korea Atomic Energy Research Institute)
• 김동석(한국원자력연구원 ATF 기술개발부) | Dong Seok Kim (ATF Technology Development Division, Korea Atomic Energy Research Institute)
• 김건식(한국원자력연구원 ATF 기술개발부) | Keon Sik Kim (ATF Technology Development Division, Korea Atomic Energy Research Institute)
• 김종헌(한국원자력연구원 ATF 기술개발부) | Jong Hun Kim (ATF Technology Development Division, Korea Atomic Energy Research Institute)