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Nishitani, Tomoyuki*; Hagihara, Takeshi*; Fujieda, Daigo; Aoyagi, Kazuhei
Tonneru To Chika, 57(2), p.135 - 145, 2026/02
no abstracts in English
Nakayama, Masashi; Ishii, Eiichi; Aoyagi, Kazuhei; Hayano, Akira; Murakami, Hiroaki; Ono, Hirokazu; Takeda, Masaki; Fukatsu, Yuta; Mochizuki, Akihito; Ozaki, Yusuke; et al.
JAEA-Review 2025-042, 136 Pages, 2025/12
JAEA-Review-2025-042.pdf:12.95MB
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant technologies for geological disposal of high-level radioactive waste through investigating the deep geological environment within the host sedimentary rocks at Horonobe-cho in Hokkaido, north Japan. In the fiscal year 2024, we continued R&D on "Study on near-field system performance in geological environment", "Demonstration of repository design options", and "Understanding of buffering behaviour of sedimentary rock to natural perturbations". These are identified as key R&D on challenges to be tackled in the Horonobe underground research plan for the fiscal year 2020 onwards. Specifically, "full-scale engineered barrier system (EBS) performance experiment" and "solute transport experiment with model testing" were carried out as part of "Study on near-field system performance in geological environment". "Demonstration of engineering feasibility of repository technology" and "evaluation of EBS behaviour over 100
C" were addressed for "Demonstration of repository design options". The validation of a method for assessing permeability using the Ductility Index and a method for estimating the state of in-situ ground pressure from hydraulic perturbation tests were investigated as part of the study "Understanding of buffering behaviour of sedimentary rock to natural perturbations". In FY2024, we continued construction of the East Access Shaft and the Ventilation Shaft, and construction of these shafts were completed to a depth of 500 m. After the completion of the East Access Shaft, excavation of the West Access Shaft and 500 m gallery has began. As of the end of FY2024, excavation progress is as follows, the East Access Shaft and the Ventilation Shaft were 500 m depth, the West Access Shaft was 472 m depth, 500 m gallery was 112.9 m, respectively. In the Horonobe International Project (HIP), Management Board and Joint Task Meeting was held at the Horonobe URL in June 2024 to review the progress of construction of galleries and preparations of experiments. Task Meetings to review the implementation plan for in-situ testing and analysis were also held. HIP will be implemented in two phases: Phase 1 (from FY2022 to FY2024) and Phase 2 (from FY2025 to FY2028), the research results of Phase 1 were compiled in FY2024.
Nakayama, Masashi; Ishii, Eiichi; Hayano, Akira; Aoyagi, Kazuhei; Murakami, Hiroaki; Ono, Hirokazu; Takeda, Masaki; Mochizuki, Akihito; Ozaki, Yusuke; Kimura, Shun; et al.
JAEA-Review 2025-027, 80 Pages, 2025/09
JAEA-Review-2025-027.pdf:6.22MB
The Horonobe Underground Research Laboratory Project is being pursued by the Japan Atomic Energy Agency to enhance the reliability of relevant technologies for geological disposal of high-level radioactive waste through investigating the deep geological environment within the host sedimentary rocks at Horonobe Town in Hokkaido, north Japan. In the fiscal year 2025, we continue R&D on "Study on near-field system performance in geological environment" and "Demonstration of repository design options". These are identified as key R&D challenges to be tackled in the Horonobe underground research plan for the fiscal year 2020 onwards. In the "Study on near-field system performance in geological environment", we continue to obtain data from the full-scale engineered barrier system performance experiment, and work on the specifics of the full-scale engineered barrier system dismantling experiment. As for "Demonstration of repository design options", the investigation, design, and evaluation techniques are to be systemized at various scales, from the tunnel to the pit, by means of an organized set of evaluation methodologies for confinement performance at these respective scales. Preliminary borehole investigations will be conducted within a 500 m gallery, with the objectives of obtaining rock strength and rock permeability data, as well as surveying the extent of the excavation damaged zone surrounding the test tunnel via tomographic analysis. A planning study for the in-situ construction test will be conducted to investigate the construction of backfill material and watertight plugs. The volume of water inflow associated with the excavation of the 500 m gallery will be observed, and its magnitude will be compared with the range of water inflow predicted in the analysis. The test plan to determine the extent of the excavation damaged zone around the pit, which is planned to be constructed in the 500 m gallery, will be studied to determine the in-situ excavation damaged zone. In addition, the investigation and evaluation methods for the amount of water inflow from fractures and the extent of the excavation damaged zone around the pit will be organized. Concerning the construction and maintenance of the subsurface facilities, excavation of the West Access Shaft and the 500 m gallery will continue. It is anticipated that the construction of the facilities will be completed by the end of the fiscal year 2025. In addition, we continue R&D on the following three tasks in the Horonobe International Project; Task A: Solute transport experiment with model testing, Task B: Systematic integration of repository technology options, and Task C: Full-scale engineered barrier system dismantling experiment.
Kuwabara, Kazumichi*; Itamoto, Masaharu*; Oyama, Katshuhiro*; Motoshima, Takayuki*; Nishitani, Tomoyuki*; Fujieda, Daigo; Togase, Kazuki; Aoyagi, Kazuhei
Shigen, Sozai Koenshu (Internet), 12(2), 7 Pages, 2025/09
no abstracts in English
Iketani, Shotaro; Suzuki, Takeshi; Yokobori, Tomohiko; Sugawara, Satoshi; Yokota, Akira; Kikuchi, Genta; Muraguchi, Yoshinori; Kitahara, Masaru; Seya, Manato; Kurosawa, Tsuyoshi; et al.
JAEA-Technology 2025-001, 169 Pages, 2025/08
JAEA-Technology-2025-001.pdf:14.22MB
The radioactive waste treatment facilities at the Nuclear Science Research Institute includes the Radioactive Waste Treatment Facility No. 3, Waste Size Reduction and Storage Facility, and Waste Volume Reduction Facility. These three facilities come under the purview of the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors, and are included under Class C of the act based on the seismic requirements specified in the Act. We assessed the seismic capacity of these three radioactive waste treatment facilities based on the current Building Standards Act, to verify whether they comply with the new regulatory requirements enforced by the Nuclear Regulation Authority (NRA) in the aftermath of the 2011 nuclear accident at the Fukushima Daiichi Nuclear Power Station operated by the Tokyo Electric Power Company. We found that the allowable stress of a few structural members used in the construction of the facilities did not meet the regulatory requirements. After studying the approval granted by the NRA for the construction plans, including the design and construction methods (design and construction plans) of the three facilities on March 5, 2021, we made aseismic reinforcement at these facilities between 2021 and 2022. This report presents an overview of the seismic design of these facilities and an outline of the aseismic reinforcement conducted, management system existing, safety measures adopted, and the preoperational inspections conducted at these facilities.
Aoyagi, Kazuhei; Murakami, Hiroaki; Tamura, Tomonori; Fujieda, Daigo; Togase, Kazuki; Sakurai, Akitaka
JAEA-Data/Code 2025-007, 62 Pages, 2025/08
JAEA-Data-Code-2025-007.pdf:5.64MB
JAEA-Data-Code-2025-007-appendix(DVD-ROM).zip:2959.56MB
We currently focus on the three tasks that were identified as "Key R&D challenges to be tackled" in the "Horonobe Underground Research Plan for the Fiscal Year 2020 Onwards". These tasks include "Study on near-field system performance in geological environment", "Demonstration of repository design options", and "Understanding of buffering behaviour of sedimentary rocks to natural perturbations". To implement these tasks, we excavate shafts and galleries to the 500 m depth. From Fiscal Year 2023, we started extension of the 350 m gallery excavating 3 horizontal gallery (Niches No.6, No.7, and 350 m Niche off the East Shaft No.1) and excavation of the shaft to the 500 m depth and excavation of 500 m gallery. This report summarizes the measurement data acquired during the excavation of Ventilation and East access shaft to accumulate the basic data for carrying out the Observational Construction Program for the excavation of the shaft to the 500 m depth.
Nagata, Shohei*; Ichida, Toshiyuki*; Fujieda, Daigo; Aoyagi, Kazuhei
Tunnelling into a Sustainable Future; Methods and Technologies; Proceedings of the ITA-AITES World Tunnel Congress 2025 (WTC 2025), p.3517 - 3524, 2025/05
We performed three-dimensional excavation analysis of three shafts and intersection of horizontal tunnel excavated to 500 m depth at Horonobe URL, and evaluated stress acting on concrete lining under various conditions such as differences in diameter of shafts, lining shape, lining thickness, concrete strength, and installation interval of the lining. The design of the support was determined based on the analysis results, and then the construction of the shafts and horizontal galleries were started. Considering the measured stress acting on the concrete lining of the shaft and sprayed mortar installed at the intersection of shaft and horizontal gallery, we could successfully excavate the shaft to 500 m depth and intersection of horizontal gallery at 420 m depth. We also concluded that appropriate support pattern can be selected based on the measured stress acting on the concrete lining and numerical analysis performed prior to the excavation. This can contribute to enhance the reliability of the appropriate observational construction technology targeting excavation of shaft.
Sakurai, Akitaka; Aoyagi, Kazuhei; Murakami, Hiroaki; Tamura, Tomonori; Fujieda, Daigo; Togase, Kazuki
JAEA-Data/Code 2024-005, 48 Pages, 2024/07
JAEA-Data-Code-2024-005.pdf:6.54MBJAEA-Data-Code-2024-005-appendix(DVD-ROM).zip:1029.9MB
We currently focus on the three tasks that were identified as "key R&D challenges to be tackled" in the "Horonobe Underground Research Plan for the fiscal year 2020 Onwards". These tasks include "Study on near-field system performance in geological environment", "Demonstration of repository design options", and "Understanding of buffering behaviour of sedimentary rocks to natural perturbations". To implement these tasks, we will excavate shafts and galleries to the 500 m depth. From fiscal year 2023, we will start extension of the 350 m gallery excavating 3 horizontal gallery (Niches No.6, No.7, and Niche of the East Shaft No.1) and excavation of the shaft to the 500 m depth and excavation of 500 m gallery. This report summarizes the measurement data acquired at Niches No.6, No.7, and Niche of the East Shaft No.1 in fiscal year 2023 to accumulate the basic data for carrying out the Observational Construction Program for the excavation of the shaft to the 500 m depth and galleries at the 500 m depth.
Yagi, Keisuke*; Yokoe, Kenichi*; Saito, Takuya*; Fujieda, Daigo; Togase, Kazuki
no journal, ,
no abstracts in English
Maeno, Katsuji*; Ichida, Toshiyuki*; Osada, Shohei*; Fujieda, Daigo; Nabana, Ryohei
no journal, ,
no abstracts in English
Shimai, Kosuke*; Nishitani, Tomoyuki*; Fujieda, Daigo; Togase, Kazuki
no journal, ,
no abstracts in English
Yamaguchi, Hajime*; Nagata, Shohei*; Otsuka, Isamu*; Nishitani, Tomoyuki*; Fujieda, Daigo; Togase, Kazuki; Aoyagi, Kazuhei
no journal, ,
no abstracts in English
Ishii, Yoshiki*; Osada, Shohei*; Otsuka, Isamu*; Ichida, Toshiyuki*; Fujieda, Daigo; Nabana, Ryohei
no journal, ,
no abstracts in English
Hirooka, Shinichi*; Maeno, Katsuji*; Oshino, Yoshiyuki*; Fujieda, Daigo; Nabana, Ryohei
no journal, ,
no abstracts in English
Ichida, Toshiyuki*; Ishii, Yoshiki*; Osada, Shohei*; Otsuka, Isamu*; Fujieda, Daigo; Nabana, Ryohei
no journal, ,
no abstracts in English
Yagi, Keisuke*; Sanoki, Satoru*; Hayano, Akira; Fujieda, Daigo; Nabana, Ryohei
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no abstracts in English
Sanda, Takayoshi*; Maeno, Katsuji*; Sanoki, Satoru*; Fujieda, Daigo; Nabana, Ryohei
no journal, ,
no abstracts in English
Hirooka, Shinichi*; Fujieda, Daigo; Togase, Kazuki
no journal, ,
no abstracts in English
