Stimulation of densification during the reduction of U3O8 to UO2 by atmosphere control. Issue 6 (15th April 2019)

• Record Type: Journal Article
• Authors: Jeon, Sang-Chae; Lee, Jae-Won; Yoon, Joo-Young; Cho, Yung-Zun; Kim, Dong-Joo; Kim, Dong Seok; Kim, Keon Sik; Kim, Jong Hun; Yang, Jae Ho
• Is Part Of: Ceramics international. Volume 45:Issue 6(2019)
• Page Start: 6863
• Page End: 6868
• Publication Date: 2019-04-15
• Subjects: Pyroprocessing -- Head-end -- Reduction kinetics -- Densification -- U3O8 -- UO2; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.12.181
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: A reduction process in the head-end for pyroprocessing has been adopted to avoid oxidation attack on the molybdenum crucible during sintering. The reduction process is employed to reduce U3 O8 pellets to UO2 prior to sintering. This allows elimination of the oxygen source, which causes oxidation attack during sintering, thereby permitting the use of a metallic crucible. However, little densification occurs due to the low reduction temperature limited by the INCONEL crucible. Consequently, the amount of material scraps from the pellets increases, thus creating an additional processing burden due to its high radioactivity. To reduce the amount of scraps, densification should be enhanced. This study suggests a simple atmospheric control strategy and clarifies its effects. With the atmospheric control, a higher bulk density and better attrition resistance were obtained in comparison to without this strategy. This can be explained in terms of O/U ratio dependent diffusion kinetics during the reduction of U3 O8 to UO2 .