A comparative review on groundwater hydrogeochemistry in countries preferring crystalline rock for deep geological disposal

• Published in: Nuclear engineering and technology Vol. 57; no. 6; p. 103463
• Main Authors: Kwon, Eunhye, Kwon, Jang-Soon, Park, Kyung-Woo, Ju, YeoJin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2025; 한국원자력학회
• Subjects: Crystalline rock; Deep geological disposal; Groundwater salinity; Seawater evaporation; Seawater freezing; Water-rock interaction; 원자력공학; Seawater freezing; Water-rock interaction; Deep geological disposal; Crystalline rock; Groundwater salinity; Seawater evaporation
• ISSN: 1738-5733; 2234-358X
• DOI: 10.1016/j.net.2025.103463

This study compares the hydrogeochemical environments of countries considering crystalline rock for deep geological disposal, with a focus on salinity differences and disposal safety. Crystalline rock is considered as a potential host in South Korea. The preference for crystalline rock is also shown in leading disposal countries, such as Finland, Sweden and Canada. However, hydrogeochemical contrasts exist, particularly in salinity. The deep groundwater in the Fennoscandian and Canadian Shields ranges from brackish to brine, forming layers with Na-Cl to Ca-Cl types, whereas most groundwater in South Korea's crystalline rock is freshwater, with some brackish or saline waters near coastal areas due to seawater intrusion. The high salinity in the Fennoscandian and Canadian Shields is attributed to Paleozoic seawater evaporation and seawater freezing by Cenozoic glaciers, compounded by limited meteoric water infiltration and water-rock interactions. In South Korea, there is no evidence of ancient seawater transgressions of glaciation. Regarding disposal safety, freshwater environments cause less degradation in disposal components and limit radionuclide mobility. This suggests that a freshwater environment can also ensure the long-term safety of deep geological disposal, from a perspective different from that of a brine environment.