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Dei, Shuntaro; Shibata, Masahito*; Negishi, Kumi*; Sugiura, Yuki; Amano, Yuki; Bateman, K.*; Wilson, J.*; Yokoyama, Tatsunori; Kagami, Saya; Takeda, Masaki; et al.
Results in Earth Sciences (Internet), 3, p.100097_1 - 100097_16, 2025/12
Interactions between cement and host rock in geological repositories for radioactive waste will result in a chemically disturbed zone, which may potentially affect the long-term safety. This paper investigates the chemical evolution at the interface between cement (Ordinary Portland Cement: OPC and Low Alkaline Cement: LAC) and mudstone after 11 years of in situ reactions at the Horonobe Underground Research Laboratory. The study combines various analytical techniques to identify the key reactions at the cement-rock interface, including cement dissolution, precipitation of secondary minerals such as calcite and C-(A-)S-H phases, cation exchange in montmorillonite and reduced porosity in mudstone. The study also highlights the effects of cement-mudstone interactions on radionuclide migration, such as reduction of diffusivity due to reduced porosity and enhancement of sorption due to incorporation into secondary minerals in the altered mudstone.
Ono, Hirokazu; Ishii, Eiichi; Takeda, Masaki
Geoenergy (Internet), 2(1), p.geoenergy2023-047_1 - geoenergy2023-047_10, 2024/12
Takeda, Masaki; Ishii, Eiichi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 31(1), p.3 - 10, 2024/06
Uunderstanding nuclide transport characteristics in the EDZ of disposal and access tunnels is an essential issue in the safety assessment of geological disposal of high-level radioactive waste. Although tracer tests are effective in evaluating the transport of nuclides in rock masses, the transport properties of EDZ in sedimentary rock, to our best knowledge, have not been investigated by in situ tracer tests. The authors conducted cross-hole tracer tests on EDZ fractures at the Horonobe Underground Research Laboratory to evaluate their longitudinal dispersibility. One-dimensional advection-dispersion analyses based on the tracer test data were performed, and the longitudinal dispersibility was estimated to be 0.12 m for the test scale of 4.2 m. This longitudinal dispersibility is 1/100 to 1/10 of the test scale, comparable with the empirical relationship between the test scale and longitudinal dispersibility for natural fractures and rock matrices. The series of tracer tests and analyses reported in this paper demonstrate that advection-dispersion occurs also in EDZ fractures similarly to natural fractures and rock matrices, and that longitudinal dispersibility in EDZ fractures can be assessed also by conventional in situ tracer test methods.
Otsuki, Daiki*; Ishida, Tatsuhiro*; Tsutsumi, Naoya*; Kobayashi, Masaki*; Inagaki, Kodai*; Yoshida, Teppei*; Takeda, Yukiharu; Fujimori, Shinichi; Yasui, Akira*; Kitagawa, Saiki*; et al.
Physical Review Materials (Internet), 7(12), p.124601_1 - 124601_6, 2023/12
Times Cited Count:2 Percentile:20.33(Materials Science, Multidisciplinary)Wang, Y.*; Kajihara, Shun*; Matsuoka, Hideki*; Saika, B. K.*; Yamagami, Kohei*; Takeda, Yukiharu; Wadachi, Hiroki*; Ishizaka, Kyoko*; Iwasa, Yoshihiro*; Nakano, Masaki*
Nano Letters, 22(24), p.9964 - 9971, 2022/12
Times Cited Count:32 Percentile:91.03(Chemistry, Multidisciplinary)Kobayashi, Masaki*; Anh, L. D.*; Suzuki, Masahiro*; Kaneta-Takada, Shingo*; Takeda, Yukiharu; Fujimori, Shinichi; Shibata, Goro*; Tanaka, Arata*; Tanaka, Masaaki*; Oya, Shinobu*; et al.
Physical Review Applied (Internet), 15(6), p.064019_1 - 064019_10, 2021/06
Times Cited Count:8 Percentile:46.19(Physics, Applied)Hirota, Noriaki; Takeda, Kiyoko*; Tachibana, Yukio; Masaki, Yasuhiro*
Zairyo To Kankyo, 70(3), p.68 - 76, 2021/03
Corrosion resistance of stainless steels and Ni-based alloys were evaluated in a sulfuric acid decomposition gas at high temperature. The evaluation were carried out in an environment simulated in the sulfuric acid decomposition reaction vessel for thermochemical hydrogen production process (IS process). Their corrosion films were also analyzed for better understanding of the corrosion behavior. As a result, after 100 hour corrosion test, Ni-based alloy containing 2.4% Si showed good corrosion resistance. Ferritic stainless steel containing 3% Al (3Al-Ferrite) showed better corrosion resistance. Its corrosion rate was lower than that of SiC (0.1mm/year), which is a candidate material for the sulfuric acid decomposition reaction vessel. On the other hand, Ni-based alloy pre-filmed with AlO
is prepared as the relative corrosion film of 3Al-Ferrite. Its corrosion rate was significantly higher than that of 3Al-Ferrite. As the result of EPMA analysis of these oxide films, Ni-based alloy containing 2.4% Si formed Si oxide film which had some cracks after the long term corrosion test. Therefore S penetrated into grain boundaries of the matrix through the oxide film. 3Al-Ferrite formed a thin and uniform Al
O
film, and the penetration of S into the grain boundaries was not observed. Al
O
pre-film of Ni-based alloy also showed S penetration in the matrix because the Al
O
pre-film had many small defects originally. The corrosion oxide film of 3Al-Ferrite consisted of only
-Al
O
, while the Al
O
pre-film consist of
-Al
O
and
-Al
O
. Those results suggest that the better corrosion resistance of 3Al-Ferrite is due to the uniform formation of dense
-Al
O
film at the early stage of the corrosion.
Matsuoka, Hideki*; Barnes, S. E.*; Ieda, Junichi; Maekawa, Sadamichi; Bahramy, M. S.*; Saika, B. K.*; Takeda, Yukiharu; Wadachi, Hiroki*; Wang, Y.*; Yoshida, Satoshi*; et al.
Nano Letters, 21(4), p.1807 - 1814, 2021/02
Times Cited Count:19 Percentile:75.94(Chemistry, Multidisciplinary)Takeda, Yukiharu; Oya, Shinobu*; Pham, N. H.*; Kobayashi, Masaki*; Saito, Yuji; Yamagami, Hiroshi; Tanaka, Masaaki*; Fujimori, Atsushi*
Journal of Applied Physics, 128(21), p.213902_1 - 213902_11, 2020/12
Times Cited Count:8 Percentile:38.75(Physics, Applied)Takeda, Takahito*; Sakamoto, Shoya*; Araki, Kosei*; Fujisawa, Yuita*; Anh, L. D.*; Tu, N. T.*; Takeda, Yukiharu; Fujimori, Shinichi; Fujimori, Atsushi*; Tanaka, Masaaki*; et al.
Physical Review B, 102(24), p.245203_1 - 245203_8, 2020/12
Times Cited Count:7 Percentile:34.47(Materials Science, Multidisciplinary)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
Hirahara, Toru*; Otrokov, M. M.*; Sasaki, Taisuke*; Sumida, Kazuki*; Tomohiro, Yuta*; Kusaka, Shotaro*; Okuyama, Yuma*; Ichinokura, Satoru*; Kobayashi, Masaki*; Takeda, Yukiharu; et al.
Nature Communications (Internet), 11, p.4821_1 - 4821_8, 2020/09
Times Cited Count:53 Percentile:90.85(Multidisciplinary Sciences)Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.
Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06
Times Cited Count:7 Percentile:55.09(Physics, Nuclear)The spallation and fragmentation reactions of Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.
Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.
Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05
Times Cited Count:19 Percentile:72.96(Physics, Multidisciplinary)The structure of a neutron-rich F nucleus is investigated by a quasifree (
) knockout reaction. The sum of spectroscopic factors of
orbital is found to be 1.0
0.3. The result shows that the
O core of
F nucleus significantly differs from a free
O nucleus, and the core consists of
35%
O
, and
65% excited
O. The result shows that the
O core of
F nucleus significantly differs from a free
O nucleus. The result may infer that the addition of the
proton considerably changes the neutron structure in
F from that in
O, which could be a possible mechanism responsible for the oxygen dripline anomaly.
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
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.
Ito, Keita*; Yasutomi, Yoko*; Zhu, S.*; Nurmamat, M.*; Tahara, Masaki*; Toko, Kaoru*; Akiyama, Ryota*; Takeda, Yukiharu; Saito, Yuji; Oguchi, Tamio*; et al.
Physical Review B, 101(10), p.104401_1 - 104401_8, 2020/03
Times Cited Count:24 Percentile:74.53(Materials Science, Multidisciplinary)Nakano, Masaki*; Wang, Y.*; Yoshida, Satoshi*; Matsuoka, Hideki*; Majima, Yuki*; Ikeda, Keisuke*; Hirata, Yasuyuki*; Takeda, Yukiharu; Wadachi, Hiroki*; Kohama, Yoshimitsu*; et al.
Nano Letters, 19(12), p.8806 - 8810, 2019/12
Times Cited Count:61 Percentile:90.73(Chemistry, Multidisciplinary)Tsushima, Masahito*; Takeda, Masaki; Ono, Hirokazu
JAEA-Data/Code 2018-008, 78 Pages, 2018/10
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.
Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.