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Sugita, Yutaka; Ono, Hirokazu; Beese, S.*; Pan, P.*; Kim, M.*; Lee, C.*; Jove-Colon, C.*; Lopez, C. M.*; Liang, S.-Y.*
Geomechanics for Energy and the Environment, 42, p.100668_1 - 100668_21, 2025/06
The international cooperative project DECOVALEX 2023 focused on the Horonobe EBS experiment in the Task D, which was undertaken to study, using numerical analyses, the thermo-hydro-mechanical (or thermo-hydro) interactions in bentonite based engineered barriers. One full-scale in-situ experiment and four laboratory experiments, largely complementary, were selected for modelling. The Horonobe EBS experiment is a temperature-controlled non-isothermal experiment combined with artificial groundwater injection. The Horonobe EBS experiment consists of the heating and cooling phases. Six research teams performed the THM or TH (depended on research team approach) numerical analyses using a variety of computer codes, formulations and constitutive laws.
Ono, Hirokazu; Takayama, Yusuke*
Geomechanics for Energy and the Environment, 41, p.100636_1 - 100636_14, 2025/03
Times Cited Count：0 Percentile：0.00(Energy & Fuels)Aoyagi, Kazuhei; Ozaki, Yusuke; Ono, Hirokazu; Ishii, Eiichi
Dai-16-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), p.269 - 274, 2025/01
We investigated the development of the excavation damaged zone (EDZ) induced by the excavation of modeled disposal pit which was excavated as a part of the full-scale engineering barrier experiment at 350 m depth. Seismic and electric tomography surveys, observation of rock core samples, borehole televiewer surveys and three-dimensional excavation analysis were performed to evaluate the extent of the EDZ around the pit. It was clarified that the EDZ was developed 0.8 to 1.6 m from the wall of the pit at a relatively shallower depth caused by the effect of the EDZ induced around the floor of the gallery. The extent of the EDZ was gradually reduced along the depth, and the maximum extension was 0.3 m from the wall of the pit at the deeper section.
Ono, Hirokazu
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 31(2), p.140 - 143, 2024/12
In the geological disposal of high-level radioactive waste, after emplacement of an EBS, the near-field environment is affected by processes such as heat release from the waste, groundwater infiltration into the EBS, swelling and deformation of the buffer material, and chemical reactions between groundwater and minerals. It is crucial to develop simulation codes to evaluate such coupled thermal-hydraulic-stress-chemical (THMC) processes for safety assessment of geological disposal. The full-scale vertical-emplacement EBS experiment (Horonobe EBS experiment) has been undertaken in the 350 m gallery of the Horonobe Underground Research Laboratory (URL) with the Horonobe geological environment. In the Horonobe EBS experiment, various sensors were installed in the buffer and backfill material to obtain the data required to evaluate coupled THMC processes in near-field. In Task C of the Horonobe International Project (HIP), the dismantling experiment of the Horonobe EBS experiment will be carried out and the data obtained from this experiment will be used to understand the coupled processes and to evaluate the simulation code.
Miyakawa, Kazuya; Ishii, Eiichi; Imai, Hisashi*; Hirai, Satoru*; Ono, Hirokazu; Nakata, Kotaro*; Hasegawa, Takuma*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 31(2), p.82 - 95, 2024/12
no abstracts in English
Ono, Hirokazu; Ishii, Eiichi; Takeda, Masaki
Geoenergy (Internet), 2(1), p.geoenergy2023-047_1 - geoenergy2023-047_10, 2024/12
Ozaki, Yusuke; Aoyagi, Kazuhei; Ono, Hirokazu; Kimura, Shun
Proceedings of 4th International Conference on Coupled Processes in Fractured Geological Media; Observation, Modeling, and Application (CouFrac2024) (Internet), 10 Pages, 2024/11
Electrical resistivity tomography was repeatedly carried out to investigate the changes of the electrical resistivity distribution around 350m Niche No. 2 and No. 4 in the Horonobe Underground Research Laboratory. The electrical resistivity around Niche No. 2 did not change so much after the high resistive zone appeared around the tunnel by the excavation under opened condition during the studied period. Around Niche No. 4, the electrical resistivity was investigated under closed condition by engineered barrier system (EBS) where the EBS and surrounding rocks were disturbed artificially by water injection and heating. Our results could capture the change in the distribution of electrical resistivity due to the artificial disturbances in and around of Niche No. 4. These results would help us to understand the time lapse behavior of excavation damaged zone and re-saturation process in and around the EBS from the construction to the closure.
Nara, Yoshitaka*; Kashiwaya, Koki*; Oketani, Kazuki*; Fujii, Hirokazu*; Zhao, Y.*; Kato, Masaji*; Aoyagi, Kazuhei; Ozaki, Yusuke; Matsui, Hiroya; Kono, Masanori*
Zairyo, 73(3), p.220 - 225, 2024/03
The fractures in the rock are the main pass of groundwater flow and solute transport. The filling of fine-grained particle, such as clay minerals, was confirmed to decrease the permeability of rock by laboratory experiment. This research aimed to verify the occurrence of the phenomena in the field. The water containing the clay minerals was injected into the rock at the 200m stage of the Mizunami Underground research laboratory. The hydraulic conductivity decreased two order before and after the injection. This result suggested that the decrease of hydraulic conductivity by the filling of fine-grained particle in the fractures occurred in the real field.
Ozaki, Yusuke; Ono, Hirokazu; Aoyagi, Kazuhei
Shigen, Sozai Koenshu (Internet), 6 Pages, 2023/09
In the Horonobe Underground Research Laboratory, the in-situ experiment for performance confirmation of engineered barrier system was performed at the 350 m stage to develop the technology for geological disposal. Several measurements have been conducted in and around the test drift to investigate the time dependent impact of the experiment on the rock and backfilled tunnel. Some measurement results are introduced in this presentation.
Ono, Hirokazu; Ishii, Eiichi
Geomechanics for Energy and the Environment, 31, p.100317_1 - 100317_9, 2022/09
Times Cited Count：8 Percentile：58.79(Energy & Fuels)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：58 Percentile：96.23(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Ono, Hirokazu; Takeda, Masaki; Ishii, Eiichi
Extended abstract of International Conference on Coupled Processes in Fractured Geological Media; Observation, Modeling, and Application (CouFrac 2020) (Internet), 4 Pages, 2020/11
Sato, Shin*; Ono, Hirokazu; Tanai, Kenji; Yamamoto, Shuichi*; Fukaya, Masaaki*; Shimura, Tomoyuki*; Niunoya, Sumio*
Jiban Kogaku Janaru (Internet), 15(3), p.529 - 541, 2020/09
no abstracts in English
on Pd(210)Ueta, Hirokazu; Sasakawa, Yuya*; Ivanov, D.*; Ono, Satoshi*; Ogura, Shohei*; Fukutani, Katsuyuki
Physical Review B, 102(12), p.121407_1 - 121407_5, 2020/09
Times Cited Count：3 Percentile：15.07(Materials Science, Multidisciplinary)Ortho-to-para conversion of molecularly chemisorbed H on a Pd(210) surface at a surface temperature of 50 K is reported. A combination of a pulsed molecular beam, photo-stimulated desorption and resonance-enhanced multiphoton ionization techniques was used for probing the change in the rotational states of molecularly chemisorbed H on the surface. Our result shows that fast ortho-para conversion of chemisorbed H occurs. The conversion time was experimentally determined to be about 2 s, which is in good agreement with a previous theoretical calculation. This agreement supports that the ortho-para conversion mechanism of the molecularly chemisorbed H on Pd(210) is the two-step process based on the hyperfine-Coulomb excitation.
Nakayama, Masashi; Saiga, Atsushi; Kimura, Shun; Mochizuki, Akihito; Aoyagi, Kazuhei; Ono, Hirokazu; Miyakawa, Kazuya; Takeda, Masaki; Hayano, Akira; Matsuoka, Toshiyuki; et al.
JAEA-Research 2019-013, 276 Pages, 2020/03
JAEA-Research-2019-013.pdf:18.72MB
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies for geological disposal of High-level Radioactive Waste through investigations of the deep geological environment within the host sedimentary rock at Horonobe Town in Hokkaido, north Japan. The investigations will be conducted in three phases, namely "Phase 1: Surface based investigations", "Phase 2: Construction phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase" (research in the underground facilities). According to the research plan described in the 3rd Mid- and Long- term Plan of JAEA, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are important issues of the Horonobe URL Project, and schedule of future research and backfill plans of the project will be decided by the end of 2019 Fiscal Year. The present report summarizes the research and development activities of these 3 important issues carried out during 3rd Medium to Long-term Research Phase.
Nakayama, Masashi; Ono, Hirokazu
JAEA-Research 2019-007, 132 Pages, 2019/12
JAEA-Research-2019-007.pdf:11.29MB
JAEA-Research-2019-007-appendix(CD-ROM).zip:39.18MB
The Horonobe Underground Research Laboratory (URL) Project has being pursued by Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formation at Horonobe, northern Hokkaido. The URL Project consists of two major research areas, "Geoscientific Research" and "Research and Development on Geological Disposal Technologies". The in-situ experiment for performance confirmation of engineered barrier system (EBS experiment) had been prepared from 2013 to 2014 fiscal year at GL-350m gallery, and heating by electric heater in simulated overpack had started in January, 2015. One of objectives of the EBS experiment is acquiring data concerned with Thermal-Hydrological-Mechanical-Chemical (THMC) coupled behavior. These data will be used in order to confirm the performance of engineered barrier system. This report shows following works had carried out at the GL-350 m gallery. Excavation of a test niche and a test pit, Setting buffer material blocks and a simulated overpack into the test pit, Backfilling the niche by compaction backfilling material and setting backfilling material blocks, Casting concrete type plug and contact grouting, Consolidate measurement system and start measuring.
Abe, Mitsushi*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05
Times Cited Count：156 Percentile：99.31(Physics, Multidisciplinary)This paper introduces a new approach to measure the muon magnetic moment anomaly 
and the muon electric dipole moment (EDM) 
at the J-PARC muon facility. The goal of our experiment is to measure 
and using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g-2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of 
e
cm.
Nakayama, Masashi; Ono, Hirokazu; Nakayama, Mariko*; Kobayashi, Masato*
JAEA-Data/Code 2019-003, 57 Pages, 2019/03
JAEA-Data-Code-2019-003.pdf:18.12MBJAEA-Data-Code-2019-003-appendix(CD-ROM).zip:99.74MB
The Horonobe URL Project has being pursued by JAEA to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formation at Horonobe, northern Hokkaido. The URL Project consists of two major research areas, Geoscientific Research and Research and Development on Geological Disposal Technologies, and proceeds in 3 overlapping phases, Phase I: Surface-based investigations, Phase II: Investigations during tunnel excavation and Phase III: Investigations in the URL, over a period of around 20 years. Phase III investigation was started in 2010 FY. The in-situ experiment for performance confirmation of engineered barrier system had been prepared from 2013 to 2014 FY at GL-350 m gallery, and heating by electric heater in simulated overpack had started in January, 2015. One of objectives of the experiment is acquiring data concerned with THMC coupled behavior. These data will be used in order to confirm the performance of engineered barrier system. This report summarizes the measurement data acquired from the experiment from December, 2014 to March, 2018. The summarized data of the EBS experiment will be published periodically.
Tsushima, Masahito*; Takeda, Masaki; Ono, Hirokazu
JAEA-Data/Code 2018-008, 78 Pages, 2018/10
JAEA-Data-Code-2018-008.pdf:6.73MBJAEA-Data-Code-2018-008(errata).pdf:0.11MBJAEA-Data-Code-2018-008-appendix(DVD-ROM).zip:263.67MB
Japan Atomic Energy Agency (JAEA) has been conducting "geoscientific study" and "research and development on geological disposal" in the Horonobe Underground Research Laboratory (URL). In-situ tracer migration test for fracture and matrix in the argillaceous rock, called for Wakkanai formation, has been conducted in the Horonobe URL project. This report summarizes data of borehole investigations and tracer migration test for fracture zone.
Takeda, Masaki; Ishii, Eiichi; Ono, Hirokazu; Kawate, Satoshi*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 25(1), p.3 - 14, 2018/06
Fault zones and excavation damaged zones have the potential to act as flow paths, and the characterization of solute transport in such zones in mudstones is important for the safe geological disposal of radioactive waste. However, few in situ tracer migration tests have been conducted on fractures in mudstones. The Japan Atomic Energy Agency has conducted in situ tracer migration experiments using uranine, for fractures in siliceous mudstone of the Wakkanai Formation. 18 experiments were conducted under various conditions An injection flow rate that is slightly higher than the pumping flow rate is ideal for tracer migration experiments involving injection and pumping, as conducted in this study. In situ tracer migration experiments involving injection and pumping conducted in a groundwater environment with dissolved gases allow empirical evaluation of the relationship of the tracer recovery ratio and the groundwater degassing with the injection and pumping flow rate ratio. This evaluation is effective for the design of experimental conditions that account for degassing and ensure high levels of tracer recovery.
