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Shirase, Mitsuyasu*; Abe, Akimasa*; Nago, Makito*; Ishii, Eiichi; Aoyagi, Kazuhei; Wakasugi, Shinichi*
Doboku Gakkai Heisei-29-Nendo Zenkoku Taikai Dai-72-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.1795 - 1796, 2017/09
JAEA has executed the underground facility construction operation from February 2011 to June 2014, while carrying out the maintenance and research project until 2018. This report is about the extra high head pump which was able to drain the high specific gravity grout drainage, which develops during grouting operation at this facility, directly from 250m underground to the surface.
Ogino, Masataka*; Owaki, Eiji*; Shirase, Mitsuyasu*; Nakayama, Masashi
Konkurito Kogaku Nenji Rombunshu (DVD-ROM), 39(1), p.703 - 708, 2017/07
no abstracts in English
Motoshima, Takayuki*; Fujita, Tomoo; Aoyagi, Kazuhei; Shirase, Mitsuyasu*; Nago, Makito*
Proceedings of 7th International Symposium on In-situ Rock Stress (RS 2016) (Internet), 9 Pages, 2016/05
Niunoya, Sumio*; Aoyagi, Kazuhei; Fujita, Tomoo; Shirase, Mitsuyasu*
Dai-44-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.336 - 341, 2016/01
In the Horonobe Underground Research Laboratory, rock mass classification and determination of mechanical properties of rock mass was conducted considering the effect of the density of fractures in the rock mass. In this paper, the authors report the mechanical properties of rock mass detected by plate loading tests and in situ shear tests in the 250 m and 350 m galleries. As a result, the failure criteria based on the result of in situ shear tests provides the most conservative value for the design of support pattern and assessment of stability of the gallery.
Kamemura, Katsumi*; Fujita, Tomoo; Aoyagi, Kazuhei; Nago, Makito*; Shirase, Mitsuyasu*; Sugawara, Kentaro*
Dai-44-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.109 - 114, 2016/01
How to estimate the initial stress state as well as a mechanical characteristic of rock mass is important in the design of deep underground structures. Some stress measurement methods using borehole, which methodology and evaluation method have been discussed in detail, are carried out if necessary. However, obtained results are often varying widely, so the evaluation of initial stress is difficult. Here, the initial stress state corresponding to the rock mass behavior of about 120m
200m area is evaluated using the convergence measurement results during tunnel excavation in 350m depth. Analysed result corresponded to that of other method, so the validity of the proposed method was shown.
Nakayama, Masashi; Shirase, Mitsuyasu*; Niunoya, Sumio*; Ono, Hirokazu; Shimohara, Masahiro*; Tanai, Kenji
no journal, ,
no abstracts in English
Ogino, Masataka*; Owaki, Eiji*; Shirase, Mitsuyasu*; Nakayama, Masashi
no journal, ,
no abstracts in English
Ono, Makoto*; Motoshima, Takayuki*; Shirase, Mitsuyasu*; Yokoyama, Satoshi*; Jo, Mayumi*; Ishii, Tomoko*; Nakayama, Masashi; Ono, Hirokazu
no journal, ,
To understand phenomenon of buffer material erosion in the vertical disposal concept, in situ tests on engineering scale have been carried out at Horonobe URL. As results of water injection with flow rate control, when water flowed in a continuous large flow rate, buffer materials did not swell enough to stop the water flow and the water flow path was confirmed to be formed by aggregated into a single pipe. Further, it was suggested that water pressure of the injection side contributes to the erosion of buffer materials.
Motoshima, Takayuki*; Shirase, Mitsuyasu*; Sanoki, Satoru*; Miyakawa, Kazuya
no journal, ,
Release of methane gas from sedimentary formations is often reported during excavation or operation of tunnels. Detecting methane gas, an odorless and colorless gas, is an important safety issue during construction and operational phases as it is explosive when mixed with air. This paper presents an approach to detect methane gas by integrating a laser methane detector into a 3-dimensional laser scanning system, including the system setup, performance of the system in the field, data implementation, and data visualization method. The system was tested at the underground research laboratory located at a depth of 350 m in sedimentary formations.
Shirase, Mitsuyasu*; Nago, Makito*; Nakayama, Masashi; Ono, Hirokazu; Sanoki, Satoru*; Shigehiro, Michiko*
no journal, ,
Full-scale engineered barrier system (EBS) experiment for high-level waste disposal is being conducted by the Japan Atomic Energy Agency at 350m level gallery in Horonobe Underground Research Laboratory, Japan, in order to obtain data for evaluating coupled THMC phenomena overtime after the installation of the EBS. This paper presents planning construction and monitoring of the engineered barrier system experiment by Construction Information Modeling.
Nakayama, Masashi; Ono, Hirokazu; Shirase, Mitsuyasu*; Niunoya, Sumio*
no journal, ,
Japan Atomic Energy Agency is conducting the in-situ experiment for verification of performance of engineered barrier system in Horonobe Underground Research Laboratory. The purpose of this paper is reporting the current status of the experiment. This paper also reports the results of saturation status of buffer material blocks.
Nakayama, Masashi; Okamoto, Reiko*; Shirase, Mitsuyasu*
no journal, ,
In Japan, high-level radioactive waste repository will be constructed in a stable host rock formation more than 300m underground. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. JAEA has developed a low alkaline cement, named as HFSC (Highly fly-ash contained silicafume cement), containing over 60wt% of silica-fume and coal ash. HFSC was used experimentally as the shotcrete material in construction of part of the 140m, 250m and 350m deep gallery in Horonobe URL. JAEA has been carrying out the investigation about interaction among cement, rock and groundwater using core samples of shotcrete and rock. In this report, the effect on surrounding rock and groundwater from shotcrete using HFSC is described through comparison with that from shotcrete using OPC.
Yamazaki, Kazutoshi*; Takao, Hajime*; Kikuchi, Takahiro*; Kuriki, Yoshiro*; Kobayashi, Masato*; Kawakubo, Masahiro*; Shirase, Mitsuyasu*; Iwata, Yumiko*; Tochigi, Yoshikatsu*; Nakayama, Gen*; et al.
no journal, ,
Among factors affecting the corrosion behavior of carbon steel overpack, in order to consider materials (size) and realistic environmental factors which are difficult to reproduce in the laboratory scale test, engineering scale tests in the underground environment were carried out. A mock-up test of the same scale was also carried out on the ground with the aim of controlling and evaluating factors that govern the corrosion phenomenon. As a result of the test for about 3 years, there was no big difference between the average corrosion amount and the maximum corrosion amount of the simulated overpack base metal and the welded part. On the other hand, unlike the laboratory scale test, localization of corrosion due to the adhesion between the buffer material and the simulated overpack was also confirmed during the initial transient period.
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.
Shirase, Mitsuyasu*; Ishii, Tomoko*; Kobayashi, Ichizo*; Jo, Mayumi*; Ono, Makoto*; Nakayama, Masashi
no journal, ,
A candidate emplacement concept of the engineered barrier system (EBS) for geological disposal in Japan is vertical emplacement option, which has a certain gap is between the wall of the disposal hole and the buffer material. This gap is considered to be filled with the swollen buffer material (self-sealing function) when the underground water is infiltrated to the buffer material. However, some underground water flow conditions such as a pipe-shaped water channel induce erosion of the buffer material, which causes lowering of the function of the EBS. Therefore, RWMC (Radioactive Waste Management Funding and Research Center) studies engineering countermeasures against piping and erosion. RWMC used an intentional water supply system to test the pre-hydration of bentonite buffers.
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.
Shirase, Mitsuyasu*; Niunoya, Sumio*; Sawada, Sumiyuki; Nakayama, Masashi; Tanai, Kenji; Matsuzaki, Tatsuji
no journal, ,
no abstracts in English
Jo, Mayumi*; Motoshima, Takayuki*; 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 mechanical removal technology using the auger method and verified the feasibility of selected technology in Horonobe URL, depth of 350 meters.
Shirase, Mitsuyasu*; Jo, Mayumi*; Motoshima, Takayuki*; Niunoya, Sumio*; Nakayama, Masashi; Tanai, Kenji
no journal, ,
no abstracts in English
Shirase, Mitsuyasu*; Niunoya, Sumio*; Yabuki, Yoshio*; Nakayama, Masashi; Ono, Hirokazu
no journal, ,
Japan Atomic Energy Agency is conducting the in-situ experiment for verification of performance of engineered barrier system in Horonobe Underground Research Laboratory. The purpose of this paper is reporting the investigation and construction technique for backfill using rock spoil from URL excavation. This paper also reports the results of quality control of in-situ measurements for backfill.