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JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2024)

Niwa, Masakazu; Shimada, Akiomi; Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Nakajima, Toru; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; et al.

JAEA-Review 2024-035, 29 Pages, 2024/09

JAEA-Review-2024-035.pdf:1.24MB

This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2024. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

Journal Articles

Ion beam induced luminescence of lanthanide complexes in organic solvents irradiated by hydrogen and argon ion beams

Nakahara, Masaumi; Watanabe, So; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yuri, Yosuke*; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Koka, Masashi*; Yamada, Naoto*; Hagura, Naoto*

Nuclear Instruments and Methods in Physics Research B, 554, p.165449_1 - 165449_5, 2024/09

 Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)

Ion beam induced luminescence analysis of lanthanide complexes in the organic solvents for minor actinides recovery process was carried out to investigate the structures of complexes. In this study, hydrogen ion beam obtained from the single-ended accelerator and argon ion beam obtained from the azimuthally varying field cyclotron were used in Takasaki Ion Accelerators for Advanced Radiation Application in National Institutes for Quantum Science and Technology. In the experiments, ion beam induced luminescence spectra of lanthanide complexes in the organic solvents were measured, and the relationship between the obtained spectra and the structures of complexes was studied.

Journal Articles

Application of transition-edge sensors for micro-X-ray fluorescence measurements and micro-X-ray absorption near edge structure spectroscopy; a case study of uranium speciation in biotite obtained from a uranium mine

Yomogida, Takumi; Hashimoto, Tadashi; Okumura, Takuma*; Yamada, Shinya*; Tatsuno, Hideyuki*; Noda, Hirofumi*; Hayakawa, Ryota*; Okada, Shinji*; Takatori, Sayuri*; Isobe, Tadaaki*; et al.

Analyst, 149(10), p.2932 - 2941, 2024/03

 Times Cited Count:1 Percentile:40.01(Chemistry, Analytical)

In this study, we successfully applied a transition-edge sensor (TES) spectrometer as a detector for microbeam X-ray measurements from a synchrotron X-ray light source to determine uranium (U) distribution at the micro-scale and its chemical species in biotite obtained from the U mine. It is difficult to separate the fluorescent X-ray of the U L$$alpha$$$$_{1}$$ line at 13.615 keV from that of the Rb K$$alpha$$ line at 13.395 keV in the X-ray fluorescence spectrum with an energy resolution of approximately 220 eV of the conventional silicon drift detector (SDD). Meanwhile, the fluorescent X-rays of U L$$alpha$$$$_{1}$$ and Rb K$$alpha$$ were fully separated by TES with 50 eV energy resolution at the energy of around 13 keV. The successful peak separation by TES led to an accurate mapping analysis of trace U in micro-X-ray fluorescence measurements and a decrease in the signal-to-background ratio in micro-X-ray absorption near edge structure spectroscopy.

Journal Articles

Ion beam induced luminescence measurements of porous silica adsorbents containing europium complexes by argon ion beam irradiation

Nakahara, Masaumi; Watanabe, So; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Yuri, Yosuke*; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yamada, Naoto*; Koka, Masashi*; Kada, Wataru*; et al.

QST-M-47; QST Takasaki Annual Report 2022, P. 64, 2024/03

An extraction chromatography method has been studied to recover minor actinides from high-level liquid waste. For effective elution of minor actinides in an adsorbent, the structures of complexes are attempted to be evaluated with ion beam induced luminescence. In this study, Eu complexes in the adsorbent were irradiated by Ar$$^{8+}$$ ion beam, and the ion beam induced luminescence spectra of Eu complexes were measured to evaluate the structures of Eu complexes.

Journal Articles

Validation of the $$^{10}$$Be ground-state molecular structure using $$^{10}$$Be($$p,palpha$$)$$^{6}$$He triple differential reaction cross-section measurements

Li, P. J.*; Beaumel, D.*; Lee, J.*; Assi$'e$, M.*; Chen, S.*; Franchoo, S.*; Gibelin, J.*; Hammache, F.*; Harada, T.*; Kanada-En'yo, Yoshiko*; et al.

Physical Review Letters, 131(21), p.212501_1 - 212501_7, 2023/11

 Times Cited Count:21 Percentile:93.59(Physics, Multidisciplinary)

The cluster structure of the neutron-rich isotope $$^{10}$$Be has been probed via the ($$p,palpha$$) reaction. The triple differential cross-section was extracted and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using the Tohsaki-Horiuchi-Schuck-R$"o$pke wave function and the wave function deduced from Antisymmetrized Molecular Dynamics calculations. The remarkable agreement between calculated and measured cross-sections in both shape and magnitude validates the description of the $$^{10}$$Be ground-state as a rather compact nuclear molecule.

JAEA Reports

Annual report for FY2021 on the activities of Naraha Center for Remote Control Technology Development (April 1, 2021 - March 31, 2022)

Akiyama, Yoichi; Shibanuma, So; Yanagisawa, Kenichi*; Yamada, Taichi; Suzuki, Kenta; Yoshida, Moeka; Ono, Takahiro; Kawabata, Kuniaki; Watanabe, Kaho; Morimoto, Kyoichi; et al.

JAEA-Review 2023-015, 60 Pages, 2023/09

JAEA-Review-2023-015.pdf:4.78MB

Naraha Center for Remote Control Technology Development (NARREC) was established in Japan Atomic Energy Agency to promote a decommissioning work of Fukushima Daiichi Nuclear Power Station (Fukushima Daiichi NPS). NARREC consists of a Full-scale Mock-up Test Building and Research Management Building. Various test facilities are installed in these buildings for the decommissioning work of Fukushima Daiichi NPS. These test facilities are intended to be used for various users, such as companies engaged in the decommissioning work, research and development institutions, educational institutions and so on. The number of NARREC facility uses was 84 in FY2021. We participated booth exhibitions and presentations on the decommissioning related events. Moreover, we also contributed to the development of human resources by supporting the 6th Creative Robot Contest for Decommissioning. As a new project, "Narahakko Children's Classroom" was implemented for elementary school students in Naraha Town. This report summarizes the activities of NARREC in FY2021, such as the utilization of facilities and equipment of NARREC, the development of remote-control technologies for supporting the decommissioning work, arrangement of the remote-control machines for emergency response, and training for operators by using the machines.

Journal Articles

Ion beam induced luminescence analysis of europium complexes in styrene-divinylbenzene copolymer-coated spherical silica by proton and argon ion beams irradiation

Nakahara, Masaumi; Watanabe, So; Takeuchi, Masayuki; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yamada, Naoto*; Koka, Masashi*; Kada, Wataru*; et al.

Nuclear Instruments and Methods in Physics Research B, 542, p.144 - 150, 2023/09

 Times Cited Count:5 Percentile:80.64(Instruments & Instrumentation)

The structures of Eu complexes in the adsorbents prepared with various extractants were evaluated by ion beam induced luminescence analysis in an extraction chromatography for minor actinides recovery. The luminescence of Eu was measured with a proton beam obtained from the single-ended accelerator and an argon ion beam obtained from the azimuthally varying field cyclotron in Takasaki Ion Accelerators for Advanced Radiation Application in National Institutes for Quantum Science and Technology. In this study, it was confirmed that the spectral shape of Eu complexes in the adsorbents varied depending on the kinds of extractants, and the correlation between the change in the spectra and the structures of Eu complexes was investigated.

Journal Articles

Simulation study on $$^{3}$$H behavior in the Fukushima coastal region; Comparison of influences of discharges from the Fukushima Daiichi and rivers

Sakuma, Kazuyuki; Yamada, Susumu; Machida, Masahiko; Kurikami, Hiroshi; Misono, Toshiharu; Nakanishi, Takahiro; Iijima, Kazuki

Marine Pollution Bulletin, 192, p.115054_1 - 115054_10, 2023/07

 Times Cited Count:4 Percentile:63.02(Environmental Sciences)

Journal Articles

High-sensitive XANES analysis at Ce L$$_{2}$$-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samples

Li, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.

Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02

 Times Cited Count:10 Percentile:66.73(Chemistry, Analytical)

no abstracts in English

Journal Articles

Ion beam induced luminescence spectra of europium complexes in silica-based adsorbent

Nakahara, Masaumi; Watanabe, So; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yamada, Naoto*; Koka, Masashi*; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Kada, Wataru*; Hagura, Naoto*

QST-M-39; QST Takasaki Annual Report 2021, P. 62, 2023/02

In an extraction chromatography method for minor actinides recovery, analysis for the structure of complex in a silica-based adsorbent has been studied to separate minor actinides efficiently. In this study, Eu was used as simulated material of minor actinides, and silica-based adsorbents containing Eu complex were prepared. The ion beam induced luminescence spectra of Eu complexes in silica-based adsorbents were measured, and the basic data for the structures of Eu complexes were obtained.

Journal Articles

Late-Holocene salinity changes in Lake Ogawara, Pacific coast of northeast Japan, related to sea-level fall inferred from sedimentary geochemical signatures

Nara, Fumiko*; Watanabe, Takahiro; Matsunaka, Tetsuya*; Yamasaki, Shinichi*; Tsuchiya, Noriyoshi*; Seto, Koji*; Yamada, Kazuyoshi*; Yasuda, Yoshinori*

Palaeogeography, Palaeoclimatology, Palaeoecology, 592, p.110907_1 - 110907_11, 2022/04

 Times Cited Count:4 Percentile:53.33(Geography, Physical)

Radiocarbon dating, tephrochronology, and geochemical signatures such as bromine (Br), iodine (I), total sulfur (TS), total organic carbon (TOC), and total nitrogen (TN) in a continuous sediment core (OG12-2) were applied to estimate past salinity change on the Lake Ogawara, Pacific coast of northeast Japan. Since the Lake Ogawara was the inner bay of the Pacific Ocean and became the brackish lake in the late Holocene, clarifying the past salinity change on the lake Ogawara could give us important insight into the past sea level changes of the Pacific Ocean. The core OG12-2 has two tephra layers, the Towada eruption and the Changbaishan eruption (B-Tm: AD 946). The age model for the core OG12-2 was established using the radiocarbon measurements of the plant residues in the core, also was constrained by the B-Tm tephra. Depletions of marine-derived elements (Br, I, and TS), from 88.4 to 64.2 mg/kg, 20.0 to 14.1 mg/kg, and 3.1 to 1.1 mass %, respectively, were observed in the layers with 2200-2000 cal BP. These results indicate paleosalinity changes from saline (inner bay) to brackish conditions within Lake Ogawara caused by sea level fluctuations during the late Holocene.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

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 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$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.

Journal Articles

Characteristics in trace elements compositions of tephras (B-Tm and To-a) for identification tools

Nara, Fumiko*; Yokoyama, Tatsunori; Yamasaki, Shinichi*; Minami, Masayo*; Asahara, Yoshihiro*; Watanabe, Takahiro; Yamada, Kazuyoshi*; Tsuchiya, Noriyoshi*; Yasuda, Yoshinori*

Geochemical Journal, 55(3), p.117 - 133, 2021/00

 Times Cited Count:6 Percentile:40.44(Geochemistry & Geophysics)

The absolute date of the Millennium Eruption (ME) of Changbaishan Volcano is widely recognized as AD 946. The Baegdosan-Tomakomai (B-Tm) tephra dispersed during the ME is a robust-age key bed. In order to identify the tephra, refractive index and major-element compositions of volcanic glass shards are conventionally used. However, trace-element analysis has been rarely carried out, especially for rare-earth elements (REEs) and for tephra layer bulk sediments. Here we present the datasets of major- and trace-element compositions datasets for the glass shards and bulk sediments of the B-Tm and Towada caldera eruptions (To-a) tephra deposits from the Lake Ogawara sediment core, Tohoku region, northern Japan. The depth profiles of the major and trace elements show the significant peaks for the K$$_{2}$$O and some trace elements (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, and U) at the B-Tm tephra layer in the Lake Ogawara sediment core, but no peaks of these elements at the To-a tephra layer. High concentrations of the trace elements in the B-Tm tephra layer were observed in individual glass shards as well as in the bulk sediment. These concentrations are highlighted by the elemental abundance pattern normalized by the crustal abundance. The elemental pattern in individual glass shards from other Japanese tephras showed significant differences from those of the B-Tm tephra, especially in REEs compositions. The trace-element compositions of the glass shards and bulk sediment show strong advantages for distinguishing the B-Tm tephra from other Japanese tephras.

JAEA Reports

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima (FY2018) (Translated document)

Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.

JAEA-Research 2020-007, 249 Pages, 2020/10

JAEA-Research-2020-007.pdf:15.83MB

The accident of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, Japan Atomic Energy Agency (JAEA) has been conducting "Long-term Assessment of Transport of Radioactive Contaminants in the Environment of Fukushima" concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.

Journal Articles

Thermal fluid activities along the Mozumi-Sukenobu fault, central Japan, identified via zircon fission-track thermochronometry

Sueoka, Shigeru; Ikuho, Zuitetsu*; Hasebe, Noriko*; Murakami, Masaki*; Yamada, Ryuji*; Tamura, Akihiro*; Arai, Shoji*; Tagami, Takahiro*

Journal of Asian Earth Sciences; X (Internet), 2, p.100011_1 - 100011_11, 2019/11

no abstracts in English

Journal Articles

Preliminary test of the EA-AGE3 system for $$^{14}$$C measurement of CaCO$$_{3}$$ samples and coral-based estimation of marine reservoir correction in the Ogasawara Islands, Northwestern Subtropical Pacific

Kokubu, Yoko; Mitsuguchi, Takehiro*; Watanabe, Takahiro; Yamada, Tsutomu*; Asami, Ryuji*; Iryu, Yasufumi*

Radiocarbon, 61(5), p.1593 - 1601, 2019/10

 Times Cited Count:2 Percentile:9.34(Geochemistry & Geophysics)

We performed $$^{14}$$C measurements of two fossil and one modern corals using a combined system of an elemental analyzer and an automated graphitization equipment AGE3 (EA-AGE3 system) and JAEA-AMS-TONO. The $$^{14}$$C concentrations (pMC values) of mid-Holocene Okinawa corals obtained by our EA-AGE3 system appear to be slightly higher than those obtained by the conventional graphitization method using phosphoric acid. The pMC increase in our EA-AGE3 system may result in significant underestimation of $$^{14}$$C age especially for older samples (e.g., 10,000 BP); however, the pMC increase is negligible in $$^{14}$$C measurements of modern or recent samples. We applied the EA-AGE3 method to the pre- and post-bomb annual-band samples from the modern Ogasawara coral for $$^{14}$$C measurements. On the basis of the pre-bomb coral $$^{14}$$C data, we estimated marine reservoir correction ($$Delta$$R) around Ogasawara Islands and its stability between $$sim$$1900 and 1950 AD.

JAEA Reports

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima (FY2018)

Nagao, Fumiya; Niizato, Tadafumi; Sasaki, Yoshito; Ito, Satomi; Watanabe, Takayoshi; Dohi, Terumi; Nakanishi, Takahiro; Sakuma, Kazuyuki; Hagiwara, Hiroki; Funaki, Hironori; et al.

JAEA-Research 2019-002, 235 Pages, 2019/08

JAEA-Research-2019-002.pdf:21.04MB

The accident of the Fukushima Daiichi Nuclear Power Station (hereinafter referred to 1F), Tokyo Electric Power Company Holdings, Inc. occurred due to the Great East Japan Earthquake, Sanriku offshore earthquake, of 9.0 magnitude and the accompanying tsunami. As a result, large amount of radioactive materials was released into the environment. Under these circumstances, JAEA has been conducting Long-term Environmental Dynamics Research concerning radioactive materials released in environment, especially migration behavior of radioactive cesium since November 2012. This report is a summary of the research results that have been obtained in environmental dynamics research conducted by JAEA in Fukushima Prefecture.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:298 Percentile:99.68(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Micro-PIXE analysis study of ferrite products synthesized from simulated radioactive liquid waste containing chemical hazardous elements

Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Nakazawa, Osamu; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*

QST-M-16; QST Takasaki Annual Report 2017, P. 140, 2019/03

no abstracts in English

Journal Articles

SiO$$_{2}$$/AlON stacked gate dielectrics for AlGaN/GaN MOS heterojunction field-effect transistors

Watanabe, Kenta*; Terashima, Daiki*; Nozaki, Mikito*; Yamada, Takahiro*; Nakazawa, Satoshi*; Ishida, Masahiro*; Anda, Yoshiharu*; Ueda, Tetsuzo*; Yoshigoe, Akitaka; Hosoi, Takuji*; et al.

Japanese Journal of Applied Physics, 57(6S3), p.06KA03_1 - 06KA03_6, 2018/06

 Times Cited Count:12 Percentile:46.67(Physics, Applied)

The advantage of SiO$$_{2}$$/AlON stacked gate dielectrics over SiO$$_{2}$$, AlON and Al$$_{2}$$O$$_{3}$$ single dielectric layers was demonstrated. Our systematic research revealed that the optimized stacked structure with 3.3-nm-thick AlON interlayer is beneficial in terms of superior interface quality, reduced gate leakage current and C-V hysteresis for next-generation high frequency and high power AlGaN/GaN MOS-HFETs.

186 (Records 1-20 displayed on this page)