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Oguri, Kaori; Hagura, Naoto*; Yamaguchi, Akiko; Okumura, Masahiko; Matsuura, Haruaki*; Tsunashima, Yasumichi; Aoki, Katsumi; Arai, Yoichi; Watanabe, So
Nuclear Instruments and Methods in Physics Research B, 556, p.165516_1 - 165516_8, 2024/11
Ningyo-toge is the uranium mine that has been operated in Japan. Various radioactive elements such as Uranium (U), and Radium (Ra) are still present in the mine ground water with very small amount, and behavior of those elements is not fully understood. In this study, we investigated the composition of metal oxides and clay minerals in a soil of slag deposit at the mine, and systematics of adsorption structure of various ions were examined. Identifying the composition and chemical forms of minerals present in the soil of slag can provide useful information for the safety assessment and evaluation of influence on the surrounding environment.
Saito, Hiroshi
JAEA-Review 2016-009, 80 Pages, 2016/07
Environmental remediation has been conducted in closed Ningyo-toge Uranium Mine, after decades of mine-related activities. During the remediation, whole procedure, priority, necessary investigations and specific methods have been examined, and issues are clarified which should be solved in the future. For that, it has been recommended that opinions are exchanged among specialists in related fields overseas, and information and their experience are referred. As part of the activities, Ningyo-toge Environmental Engineering Center has been involved continuously in IAEA ENVIRONET, multinational network for environmental remediation. Also, bonds are tightened among participants and IAEA by exchanging opinions and sharing the issues. In parallel, literature survey has been conducted to supplement the information obtained through ENVIRONET and to clarify additionally-required information and targeted sites. The expected information are obtained from the site-visits and now being organized.
Saito, Hiroshi; Sato, Yasushi*; Sakamoto, Atsushi*; Torikai, Kazuyoshi; Fukushima, Shigeru; Sakao, Ryota; Taki, Tomihiro
JAEA-Technology 2015-063, 119 Pages, 2016/03
Ningyo-toge Environmental Engineering Center has been conducting environmental remediation of the Ningyo-toge Uranium Mine, after decades of mine-related activities were terminated. Its purposes are to take measures to ensure safety and radiation protection from the exposure pathways to humans in future, and to prevent the occurrence of mining pollution. As part of the remediation, upstream part of the Yotsugi Mill Tailings Pond, the highest prioritized facility, has been remediated to fiscal year 2012. Multi-layered capping has been constructed using natural material, after specifications and whole procedure being examined in terms of long-term stability, radiation protection, economics, etc. Monitoring has been carried out to confirm the effectiveness of the capping, in terms of settlement, dose and radon exhalation rates, etc. Monitoring of drainage volume of penetrated rainwater is planned. Accumulated data will be examined and used for remediation of downstream part of the Pond.