Decontamination of concrete waste from nuclear power plant decommissioning in South Korea. (15th December 2020)

• Record Type: Journal Article
• Authors: Han, Sangsoo; Hong, Seokju; Nam, Seongsik; Kim, Won-Seok; Um, Wooyong
• Is Part Of: Annals of nuclear energy. Volume 149(2020)
• Publication Date: 2020-12-15
• Subjects: Decommissioning -- Radioactive concrete -- Concrete decontamination -- Thermal treatment; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2020.107795
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: Co-spiked concrete sample was prepared to simulate an irradiated concrete waste. Thermal treatment was optimized to reduce the volume of concrete waste. The optimized temperature for degrading the concrete is between 500 and 550 °C. The Co phase changed from Co3 O4 to CoO during thermal treatment. The most efficient chemical decontamination solution was HCl (5 M) for >99% removal. Abstract: This study investigates for optimizing thermal treatment conditions for the effective decontamination of cobalt(Co)-contaminated concrete waste. About 21 g of ordinary Portland cement (OPC, Type I), 37 g of dry sand, 5 g of fly ash, and 24 g of aggregates were mixed, cured for 28 days, and used for characterization and thermal treatment. Thermal treatment was conducted at different temperatures between 105 °C and 600 °C. The samples were characterized using SEM, XRD, FTIR, XRF, and XAS. Up to 600 °C, mass loss only occurred for water molecules in the concrete with ~60% volume reduction, suggesting an optimum temperature between 500 °C and 550 °C. During thermal treatment, Co phase changed from Co3 O4 to CoO, and among the various chemical solutions, chloric acid exhibits the highest Co decontamination efficiency. The results suggest that a combination of thermal and chemical treatments can enhance Co removal from concrete waste.