In Japan, spent nuclear fuel from nuclear power plant is reprocessed to recover reusable materials like uranium and plutonium. The remaining high-level radioactive waste (HLW), which cannot be recycled, is vitrified into stable glass form. Since HLW remains radioactive for a long period of time, it must be safely isolated from the human environment. For this reason, it is planned to be disposed of deep underground within stable rock formations, a method called "Geological disposal".

At the Tono Geoscience Center, we conduct research to improve the safety and reliability of geological disposal technology. We study natural processes—such as uplift, erosion, faulting, earthquakes, deep-seated fluids, and volcanic activity—that may affect the long-term stability of disposal sites. We also refine dating techniques to better understand how these processes have evolved over time. In addition, we analyze the deep underground environment, including current and future groundwater flow, to help the assessment of long-term safety.