瑞浪超深地層研究所における研究と建設の現状と課題,1

Status and subject of investigation and construction at Mizunami Underground Research Laboratory, 1

佐藤 稔紀  ; 竹内 真司; 見掛 信一郎 ; 杉原 弘造

Sato, Toshinori; Takeuchi, Shinji; Mikake, Shinichiro; Sugihara, Kozo

瑞浪超深地層研究所は、平成17年2月には本格的な立坑掘削を開始し、同年10月に主立坑172m,換気立坑191mに到達したところで、立坑排水中のふっ素とほう素が環境基準を超過するという問題が生じたため、立坑からの排水を停止し、掘削工事を一時休止した。排水処理設備を増強し、平成18年4月に掘削工事を再開し、両立坑からパイロットボーリング調査を実施した。今後は、湧水抑制対策を実施しながら、調査研究を行いつつ、掘削を進めていく計画である。本報告では、瑞浪超深地層研究所の建設と研究の現状と課題を示す。

The Mizunami Underground Research Laboratory, one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is being constructed in Mizunami City. By October 2005, the excavation of the Main and Ventilation Shafts had reached depths of 172m and 191m, respectively. However, shaft sinking was then suspended for about 6 months due to high concentrations of boron and fluorine in the inflow water in the shafts, which exceeded the environmental discharge limits. To resolve this problem, an additional effluent treatment system was adopted, and shaft sinking restarted in April 2006. Pilot boring investigations were performed at the both shafts. This report shows the status and subject of investigations and construction of Mizunami Underground Research Laboratory.