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Yoshida, Hidekazu*; Yamamoto, Koshi*; Asahara, Yoshihiro*; Maruyama, Ippei*; Karukaya, Koichi*; Saito, Akane*; Matsui, Hiroya; Mochizuki, Akihito; Jo, Mayumi*; Katsuta, Nagayoshi*; et al.
Communications Engineering (Internet), 3, p.67_1 - 67_10, 2024/05
A capability to permanently seal fluid flow-paths through bedrock, like boreholes or underground tunnels, is needed to ensure the long-term safety and effectiveness of many underground activities e.g. CO
storage, hydrocarbon field abandonment, and nuclear waste disposal. Commonly used cementitious seals may not be sufficiently durable due to chemical and physical degradation. Learning from natural calcite (CaCO
) concretion formation, a more durable sealing method was developed using a "concretion-forming solvent". The method was tested by sealing flow-paths next to a tunnel in an underground research laboratory at 350 meters depth. The flow-paths initially sealed rapidly, then resealed after disturbance by earthquakes (M5.4). The treated rock recovered its very low natural permeability, demonstrating permanent sealing that is robust.
Sawaguchi, Takuma; Takai, Shizuka; Sasagawa, Tsuyoshi; Uchikoshi, Emiko*; Shima, Yosuke*; Takeda, Seiji
MRS Advances (Internet), 8(6), p.243 - 249, 2023/06
In the intermediate depth disposal of relatively high-level radioactive waste, a method to confirm whether the borehole for monitoring is properly sealed should be developed in advance. In this study, groundwater flow analyses were performed for the hydrogeological structures with backfilled boreholes, assuming sedimentary rock area, to understand what backfill design conditions could prevent significant water pathways in the borehole, and to identify the confirmation points of borehole sealing. The results indicated the conditions to prevent water pathways in the borehole and BDZ (Borehole Disturbed Zone), such as designing the permeability of bentonite material less than or equal to that of the host rock, and grouting BDZ.
Ogata, Sho*; Yasuhara, Hideaki*; Aoyagi, Kazuhei; Kishida, Kiyoshi*
Proceedings of 53rd US Rock Mechanics/Geomechanics Symposium (USB Flash Drive), 6 Pages, 2019/06
Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Kubo, Shinji
International Journal of Hydrogen Energy, 44(25), p.12583 - 12592, 2019/05
Times Cited Count：20 Percentile：53.68(Chemistry, Physical)JAEA has been conducting R&D on thermochemical water-splitting hydrogen production IS process to develop one of heat applications of high-temperature gas-cooled reactor. A test facility was constructed using corrosion-resistant industrial materials to verify integrity of the IS process components and to demonstrate continuous and stable hydrogen production. The performance of components installed in each section was confirmed. Subsequently, a trial operation of integration of the processing sections was successfully carried out for 8 hours with hydrogen production rate of approximately 10 NL/h. After that, hydrogen production operation was extended to 31 hours (approximately hydrogen production rate of 20 NL/h) by introducing a corrosion-resistance pump system with a developed shaft seal technology.
Jo, Mayumi*; Ono, Makoto*; Nakayama, Masashi; Asano, Hidekazu*; Ishii, Tomoko*
Geological Society Special Publications, 482, 16 Pages, 2018/09
Times Cited Count：2 Percentile：19.31(Geology)Isozaki, Futoshi*; Kikuchi, Taiji; Ioka, Ikuo; Ishikawa, Kazuyoshi; Hirata, Yuji*
JAERI-Tech 2002-074, 22 Pages, 2002/09
JAERI-Tech-2002-074.pdf:4.98MB
The pressurized tube specimens which enclosed high pressure inert gas were produced for the irradiation creep test. The pressurized tube specimen with 7mm outer diameter and 0.5mm wall thickness must be sealed by the welding, after the helium gas was impressed in the inside of tube. In this process, there was a technical problem of welding under high pressure, and it is difficult to seal the pressurized tube specimen in the present facility of our group. The production process was examined by taking shortening in production period and reduction in the cost into consideration. The sealing technology to enclose the helium gas up to 5.5MPa was established by new technique using the present facility and the mock-up test. And, it is necessary to measure the outer diameter of the pressurized tube specimen with high accuracy in order to predict irradiation creep deformation arising from neutron radiation and internal pressure. Therefore, the method for measuring at the 0.01mm measurement accuracy was established, which combined laser measuring instrument with the lathe.
Oketani, Kazuki*; Nara, Yoshitaka*; Matsui, Hiroya; Fujii, Hirokazu*
no journal, ,
For the geological disposal of radioactive wastes, it is important to understand the long-term migration of radionuclides. The network of fractures and pores in a rock mass, which have a role as the pathway of the fluid flow of materials, may change due to sealing of a material in the long term. We measured changes in hydraulic conductivity of crystalline rock mass using water mixed with clays sampled from a fault in the Mizunami Underground Research Laboratory, Japan Atomic Energy Agency. This result indicates that permeability of in-situ rock mass is possible to decrease by fracture filling with a clay material in a fault.
Yoshida, Hidekazu*; Yamamoto, Koshi*; Karukaya, Koichi*; Matsui, Hiroya
no journal, ,
no abstracts in English
Yoshida, Hidekazu*; Yamamoto, Koshi*; Maruyama, Ippei*; Asahara, Yoshihiro*; Minami, Masayo*; Shirono, Shinichi*; Hasegawa, Hitoshi*; Katsuta, Nagayoshi*; Nishimoto, Shoji*; Muramiya, Yusuke*; et al.
no journal, ,
no abstracts in English
Kimura, Shun; Takeda, Masaki; Motoshima, Takayuki*
no journal, ,
