2:15 PM - 2:45 PM
★ [U05-12] Geomicroiology of Uranium - Challenges for the Deep Geological Environment
Keywords:uranium, microorganisms, redox transformation, underground research laboratory
Our understanding of uranium mobility in the environment has been rapidly expanding in the past decades, especially due to problems associated with environmental remediation of uranium-contaminated sites and geological disposal of spent fuels composed mostly of UO2. Although neither of these environmental problems was relevant in Japan, Fukushima Daiichi nuclear disaster has dramatically changed our situation. Despite the significant advancement, it is still difficult to predict the form, distribution and fate of uranium in the deep subsurface, as exemplified by studies of a Swedish geological disposal site where high concentrations of uranium was unexpectedly found in the granitic aquifer. In this presentation, the state of the art investigations of microbially mediated redox reactions and uranium mobility in the deep granitic aquifer at Mizunami Underground Research Laboratory (URL) will be presented to discuss factors controlling long-term uranium migration, as well as the relevance to the formation processes of Tono uranium deposit nearby the URL.