Proposal of an absolute dating method for groundwater using the reconstruction of cosmic ray-derived 81Kr variations over the past 1 million years

2024 Fiscal Year Final Research Report

• Project/Area Number: 21K18921
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 31:Nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Ohta Tomoko 長岡技術科学大学, 工学研究科, 准教授 (30373020)
• Co-Investigator(Kenkyū-buntansha): 窪田 卓見 京都大学, 複合原子力科学研究所, 助教 (90335240)
• Project Period (FY): 2021-07-09 – 2025-03-31
• Keywords: 地下水 / 放射性核種 / 宇宙線生成核種 / 地下水年代

Outline of Final Research Achievements

The selection of sites for the disposal of high-level radioactive waste (HLW) represents a considerable challenge for the international community. In order to obtain information on radionuclides in deep underground, groundwater age, and the origin of groundwater in the country's sedimentary rock areas, field surveys were conducted. These field surveys involved the chemical separation and purification of radionuclides in groundwater, and laboratory tests were then carried out in order to investigate factors affecting the accuracy of groundwater age determination.

Free Research Field

環境動態解析

Academic Significance and Societal Importance of the Research Achievements

高レベル放射性廃棄物（HLW）の処分サイトの選定は国際社会における課題である。地下深部の埋設部より放射性核種が滲出したときに、核種が地下深部を移動 できる駆動力は地下水のみである。本邦の堆積岩地帯のフィールドで地下深部の核種情報、地下水年代（涵養時間）、地下水の起源情報を得るためのフィールド試験、室内試験を行い、地下水年代測定の精度に係わる要因を見出す研究を行った。