Physicochemical Property of Borosilicate Glass for Rare Earth Waste From the PyroGreen Process

• Published in: Journal of nuclear fuel cycle and waste technology (Online) 2023, 21(2), , pp.271-281
• Main Authors: Hwang, Young Hwan, Lee, Mi-Hyun, Kim, Cheon-Woo
• Format: Article
• Language: English
• Subjects: 원자력공학
• ISSN: 1738-1894; 2288-5471
• DOI: 10.7733/jnfcwt.2023.019

A study was conducted on the vitrification of the rare earth oxide waste generated from the PyroGreen process. The target rare earth waste consisted of eight elements: Nd, Ce, La, Pr, Sm, Y, Gd, and Eu. The waste loading of the rare earth waste in the developed borosilicate glass system was 20wt%. The fabricated glass, processed at 1,200℃, exhibited uniform and homogeneous surface without any crystallization and precipitation. The viscosity and electrical conductivity of the melted glass at 1,200℃ were 7.2 poise and 1.1 S·cm−1, respectively, that were suitable for the operation of the vitrification facility. The calculated leaching index of Cs, Co, and Sr were 10.4, 10.6, and 9.8, respectively. The evaluated Product Consistency Test (PCT) normalized release of the glass indicated that the glass satisfied the requirements for the disposal acceptance criteria. Furthermore, the pristine, 90 days water immersed, 30 thermal cycled, and 10 MGy gamma ray irradiated glasses exhibited good compressive strength. The results indicated that the fabricated glass containing rare earth waste from the PyroGreen process was acceptable for the disposal in the repository, in terms of chemical durability and mechanical strength.