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Matsui, Hiroya; Yahagi, Ryoji*; Ishizuka, Hikaru*; Toguri, Satohito*
WIT Transactions on Ecology and the Environment, Vol.247, p.145 - 159, 2020/00
In situ backfilling experiment using spray method in the small scale drift (approximately 4 by 3 m scale) was conducted at 500 m depth in Mizunami Underground Research Laboratory (MIU) established by JAEA (Japan Atomic Energy Agency). The backfill material consists of sand and bentonite. Specification for the backfill material was designed to satisfy the target permeability of generic host rock (10
m/sec) assumed by NUMO. In this case, effective clay density should be 0.4 Mg/m
or more. Quality control of the material before backfilling was performed by setting the initial water contents (average 14%) based on the results of the laboratory testing and preliminary spray testing on ground surface. Densities of the backfilled material measured at any points satisfied the specification and the results suggested the establishment of the practical quality control methodology of the backfilling by spray method under actual deep geological environment. The in situ experiment was sponsored by METI (Ministry of Environment, Trade and Industry).
Matsui, Hiroya; Yahagi, Ryoji*; Okihara, Mitsunobu*; Toguri, Satohito*
no journal, ,
This report describes the overall plan of in-situ test to backfill a part of Mizunami Underground Research Laboratory, which is planned for development of tunnel backfilling method.
Yahagi, Ryoji*; Ishizuka, Hikaru*; Toguri, Satohito*; Matsui, Hiroya
no journal, ,
This repot summarize about the selection of the material and machines for in-situ experiment for the backfilling in a small scale drift by spray method funded by METI.
Ishizuka, Hikaru*; Yahagi, Ryoji*; Toguri, Satohito*; Matsui, Hiroya
no journal, ,
This repot summarize about the results of the in-situ experiment for the backfilling in MIU by spray method funded by METI.
Iso, Sachie*; Motoshima, Takayuki*; Shirase, Mitsuyasu*; Kobayashi, Masato*; Nakayama, Masashi
no journal, ,
In the high-level radioactive waste disposal project, backfilling the disposal tunnel using soil-bentonite mixtures has been developed. Authors have developed the shotclay method and machinery through elemental test on ground test site, and conducted in-situ verification test on Horonobe URL, underground test site deeper than 300m. In this paper, authors confirmed the workability and the quality of shotclay method in the underground conditions.
Motoshima, Takayuki*; Jo, Mayumi*; Iso, Sachie*; Shirase, Mitsuyasu*; Kobayashi, Masato*; Nakayama, Masashi
no journal, ,
Radioactive waste needs to be managed responsibly even after the waste is transported to the final disposal site. Reversibility and retrievability are also required in high level radioactive waste disposal project. From the viewpoint of the technical feasibility of the retrievability, the development of a technology for removing the bentonite backfilling material surrounding the PEM without damaging the PEM is expected. In this paper, we selected the liquid removal technology using the water jet method and verified the feasibility of selected technology in Horonobe URL, depth of 350 meters.
Kimura, Shun; Takeda, Masaki; Motoshima, Takayuki*; Dan, Hanae*
no journal, ,
no abstracts in English
Kimura, Shun; Takeda, Masaki; Motoshima, Takayuki*; Dan, Hanae*
no journal, ,
no abstracts in English
Matsui, Hiroya; Motoshima, Takayuki*; Shibata, Masahito*; Sakamoto, Ryo*; Mochizuki, Akihito
no journal, ,
no abstracts in English
