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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.

JAEA Reports

Separation of radiocaesium-bearing micro particle from environmental samples; Application to litter samples

Tagomori, Hisaya; Dohi, Terumi; Ishii, Yasuo; Kanaizuka, Seiichi*; Fujiwara, Kenso; Iijima, Kazuki

JAEA-Technology 2019-001, 37 Pages, 2019/03

JAEA-Technology-2019-001.pdf:26.85MB

An efficient methodology for separating the radiocaesium-bearing micro particles (CsMPs) released by the TEPCO's Fukushima Dai-ichi Nuclear Power Station accident is required to investigate their spatial distribution and physicochemical properties. In this report we developed an efficiency separation method for CsMP from litters since the radiocaesium in litter may affect the radiocaesium cycling in forest ecosystem. One CsMP separation from litter containing lots of soil particles was attained within three days using electron microscopic analysis with digestion treatment of organic matter. This methodology is expected as CsMPs efficient separation method for not only forest floor litter but also barks and leaves of living tree, and other organic materials in the forested environment.

Journal Articles

Amount of radioactive cesium sedimentation in a soil saving dam with 3D laser scanner

Watanabe, Takayoshi; Oyama, Takuya; Ishii, Yasuo; Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito

KEK Proceedings 2017-6, p.122 - 126, 2017/11

no abstracts in English

Journal Articles

Translocation of radiocesium released by the Fukushima Daiichi Nuclear Power Plant accident in Japanese chestnut and chestnut weevil larvae

Sasaki, Yoshito; Ishii, Yasuo; Abe, Hironobu; Mitachi, Katsuaki; Watanabe, Takayoshi; Niizato, Tadafumi

Horticulture Journal, 86(2), p.139 - 144, 2017/04

To examine the translocation of radiocesium (Cs) scattered by the Fukushima Daiichi Nuclear Power Plant accident that occurred in March 2011 to the Japanese chestnut, we investigated the autoradiography and radiocesium concentration in each part of the Japanese chestnut. The Japanese chestnut fruit has a thin skin between the kernel (cotyledons) and shell; the kernel of the fruit is edible. $$^{137}$$Cs concentration in each part of the fruit was found to be almost the same at about 1.0$$times$$10$$^{4}$$ Bq$$cdot$$kg$$^{-1}$$. Radiocesium concentration in chestnut weevil larvae found on the fruit was approximately one-seventh of that in the kernel.

Journal Articles

The Transfer of radiocesium from the bark to the stemflow of chestnut trees (${it Castanea crenata}$) contaminated by radionuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

Sasaki, Yoshito; Abe, Hironobu; Mitachi, Katsuaki; Watanabe, Takayoshi; Ishii, Yasuo; Niizato, Tadafumi

Journal of Environmental Radioactivity, 161, p.58 - 65, 2016/09

AA2015-0311.pdf:1.93MB

 Times Cited Count:5 Percentile:55.17(Environmental Sciences)

We report the behavior of radiocesium on the tree bark and its transfer into the stemflow of chestnut in a forest in Fukushima. The radiocesium concentration is greatest in $$phi$$2-cm stem, less in $$<$$$$phi$$5-mm stem, and least in the leaves. In the $$phi$$2-cm stem, the radiocesium concentration of the bark was approximately 10 times that of wood. The average Cs-137 concentration of the dissolved fraction of stem flow was about 10 Bq/L; the pH was nearly constant at 5.8. A strong positive correlation was observed between the radiocesium concentration and the electrical conductivity of the dissolved fraction of stemflow; this result suggests that radiocesium and electrolytes have the same elution mechanism from the tree. Some of the particles in the particulate fraction of the stem flow was strongly adsorbed radiocesium.

Journal Articles

Input and output budgets of radiocesium concerning the forest floor in the mountain forest of Fukushima released from the TEPCO's Fukushima Dai-ichi Nuclear Power Plant accident

Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito; Ishii, Yasuo; Watanabe, Takayoshi

Journal of Environmental Radioactivity, 161, p.11 - 21, 2016/09

 Times Cited Count:10 Percentile:29.65(Environmental Sciences)

Estimations of radiocesium input and output budgets concerning the forest floor in a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, after 2 to 3 year period following the TEPCO Fukushima Dai-ichi Nuclear Power Plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at the experimental plots have been monitored on a forest floor of evergreen Japanese cedar and deciduous Konara oak forests. The results at both monitoring locations show the radiocesium input to be 4-50 times higher than the output during the rainy season in Fukushima. These results indicate that the radiocesium tend to be preserved in the forest ecosystem due to extremely low output ratios. Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels.

Journal Articles

Clay-based modeling approach to diffusion and sorption in the argillaceous rock from the Horonobe URL; Application to Ni(II), Am(III), and Se(IV)

Tachi, Yukio; Suyama, Tadahiro; Yotsuji, Kenji; Ishii, Yasuo; Takahashi, Hiroaki*

CMS Workshop Lectures, Vol.21, p.241 - 250, 2016/00

Sorption and diffusion of radionuclides in argillaceous rocks are key processes in the safe geological disposal. The diffusion and sorption behavior of Ni(II), Am(III) and Se(IV) in mudstone from the Horonobe URL were investigated by experimental and modeling approaches. Effective diffusivities obtained by the through-diffusion experiments were in the sequence of Cs$$^{+}$$, Ni$$^{2+}$$, HTO, I$$^{-}$$, Se(SeO$$_{4}$$$$^{2-}$$), Am(Am(CO$$_{3}$$)$$^{2-}$$) by comparison with the previous study. The distribution coefficient values were consistent with those obtained by batch sorption tests. These results were interpreted by the clay-based modeling approach coupling the thermodynamic sorption model assuming key contributions of clays (smectite and illite) and the diffusion model assuming the electrical double layer theory and the simplified pore model with size distribution. This clay-based model could provide reasonable account of observed trends and could be basically applicable for various radionuclides.

Journal Articles

Development of a measurement system for the determination of ($$n,gamma$$) cross-sections using multi-nucleon transfer reactions

Makii, Hiroyuki; Ota, Shuya*; Ishii, Tetsuro; Wakabayashi, Yasuo*; Furutaka, Kazuyoshi; Nishio, Katsuhisa; Nishinaka, Ichiro; Chiba, Satoshi; Igashira, Masayuki*; Czeszumska, A.*

Nuclear Instruments and Methods in Physics Research A, 797, p.83 - 93, 2015/10

 Times Cited Count:3 Percentile:53.75(Instruments & Instrumentation)

We have installed new experimental apparatus to measure $$gamma$$ rays from highly excited states populated by the multi-nucleon transfer reactions with heavy-ion projectiles to determine the ($$n, gamma$$) cross sections by means of the surrogate reaction method. Apparatus consists of two anti-Compton LaBr$$_{3}$$(Ce) spectrometers to measure the $$gamma$$ rays and a Si $${Delta}E$$-$$E$$ detector system to detect outgoing projectile-like particles. Reactions of 153-MeV $$^{18}$$O beams with $$^{155}$$Gd and $$^{157}$$Gd targets were used to study the performance of apparatus. By using the LaBr$$_{3}$$(Ce) scintillators with relatively large volume (101.6 mm in diameter and 127 mm in length), we have successfully measured $$gamma$$ rays from the compound nuclei, which have excitation energy above neutron separation energy, populated by $$^{155}$$Gd($$^{18}$$O, $$^{16}$$O)$$^{157}$$Gd and $$^{157}$$Gd($$^{18}$$O, $$^{16}$$O)$$^{159}$$Gd two-neutron transfer reactions. The present study has demonstrated high capability of apparatus to measure the de-excitation $$gamma$$ rays in the compound nuclei produced by the multi-nucleon transfer reactions for determination of the ($$n, gamma$$) cross sections by using the surrogate reaction method.

Journal Articles

Deposition of radioactive caesium in the Fukushima mountain forests by the Fukushima Nuclear Power Plant accident

Ishii, Yasuo; Abe, Hironobu; Niizato, Tadafumi

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 3 Pages, 2015/05

As part of the project entitled "Long-Term Assessment of Transport of Radioactive Contaminant in the Environment of Fukushima" (F-TRACE project), JAEA has researched since November 2012 to predict the transport behavior of radioactive caesium, which now Cs-134 and Cs-137 are the main radiological contribution, from contaminated mountain forests to estuary and coast through dam, pond, river etc. based on their investigated data survey data in the Fukushima prefecture. In this study, we report characterization and radio assay of the surface run-off substances obtained (or collected) at the forest observation plots in the Ogi district of Kawauchi-mura and the Yamakiya district of Kawamata-machi, and at the soil-saving dam in the Ogaki district of Namie-machi, Fukishima prefecture, Japan.

Journal Articles

Towards optimizing the performance of self-regenerating Pt-based perovskite catalysts

Jarrige, I.*; Ishii, Kenji; Matsumura, Daiju; Nishihata, Yasuo; Yoshida, Masahiro*; Kishi, Hirofumi*; Taniguchi, Masashi*; Uenishi, Mari*; Tanaka, Hirohisa*; Kasai, Hideaki*; et al.

ACS Catalysis, 5(2), p.1112 - 1118, 2015/02

 Times Cited Count:8 Percentile:61.22(Chemistry, Physical)

Journal Articles

Development of anti-Compton LaBr$$_{3}$$(Ce) spectrometer for measurement of surrogate reactions

Makii, Hiroyuki; Ota, Shuya*; Ishii, Tetsuro; Nishio, Katsuhisa; Nishinaka, Ichiro; Furutaka, Kazuyoshi; Wakabayashi, Yasuo*; Chiba, Satoshi*; Igashira, Masayuki*

Nuclear Data Sheets, 119, p.361 - 364, 2014/05

 Percentile:100(Physics, Nuclear)

Anti-Compton LaBr$$_{3}$$(Ce) spectrometers have been installed at JAEA-Tokai tandem accelerator facility in order to measure the $$gamma$$ rays from the highly excited states produced by surrogate reactions. Each spectrometer consists of a central LaBr$$_{3}$$(Ce) detector with a diameter of 10.2 cm and a length of 12.7 cm, and an annular BGO detector with a thickness of 2.5 cm and a length of 25.4 cm. In this contribution, we will present the results of performance test using the standard $$gamma$$ ray source and high-energy $$gamma$$ rays from the $$^{27}$$Al(p,$$gamma$$)$$^{28}$$Si reaction, and a measurement plan for (n,$$gamma$$) cross sections using a surrogate reaction at JAEA-Tokai tandem accelerator facility.

Journal Articles

Ground-state configuration of the $$N=157$$ nucleus $$^{259}$$No

Asai, Masato; Tsukada, Kazuaki; Sakama, Minoru*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ishii, Yasuo; Toyoshima, Atsushi; Ishii, Tetsuro; Nishinaka, Ichiro; Nagame, Yuichiro; et al.

Physical Review C, 87(1), p.014332_1 - 014332_6, 2013/01

 Times Cited Count:4 Percentile:57.51(Physics, Nuclear)

The spin-parity and neutron configuration of the ground state of $$^{259}$$No have been identified through $$alpha$$-decay spectroscopy. The $$^{259}$$No is the nucleus with the largest neutron number whose spin-parities and single-particle configurations have ever been identified. The neutron 9/2$$^{+}$$[615] configuration was assigned to the ground state of $$^{259}$$No as well as to the 231.4 keV level in $$^{255}$$Fm. This allowed us to establish energy spacings and order of the neutron single-particle orbitals in such heaviest nuclear region. The appearance of the 9/2$$^{+}$$[615] ground state at $$N$$=157 implies that the order of the neutron orbitals between the $$N$$=152 and 162 deformed shell gaps should change considerably with increasing neutron number.

Journal Articles

Electronic excitations around the substituted atom in La$$_2$$Cu$$_{1-y}$$N$$_y$$O$$_4$$ as seen via resonant inelastic X-ray scattering

Ishii, Kenji; Tsutsui, Kenji; Ikeuchi, Kazuhiko*; Jarrige, I.; Mizuki, Junichiro; Hiraka, Haruhiro*; Yamada, Kazuyoshi*; Toyama, Takami*; Maekawa, Sadamichi; Endo, Yasuo*; et al.

Physical Review B, 85(10), p.104509_1 - 104509_5, 2012/03

 Times Cited Count:3 Percentile:79.94(Materials Science, Multidisciplinary)

Journal Articles

Analysis on the co-localization of asbestos bodies and Fas or CD163 expression in asbestos lung tissue by in-air micro-PIXE

Dobashi, Kunio*; Shimizu, Yasuo*; Matsuzaki, Shinichi*; Nagamine, Takeaki*; Sato, Takahiro; Okubo, Takeru; Yokoyama, Akihito; Ishii, Yasuyuki; Kamiya, Tomihiro; Arakawa, Kazuo*; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 87, 2012/01

Journal Articles

Fluorido complex formation of element 104, rutherfordium (Rf)

Ishii, Yasuo; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Li, Z.*; Nagame, Yuichiro; Miyashita, Sunao*; Mori, Tomotaka*; Suganuma, Hideo*; Haba, Hiromitsu*; et al.

Bulletin of the Chemical Society of Japan, 84(9), p.903 - 911, 2011/09

 Times Cited Count:12 Percentile:50.96(Chemistry, Multidisciplinary)

The cation-exchange behavior of element 104, rutherfordium (Rf), was investigated together with its lighter group-4 homologues Zr and Hf, and the tetravalent pseudo-homologue Th in HF/HNO$$_{3}$$ mixed solution. The results demonstrate that distribution coefficients ($$K_{d}$$) of Rf in HF/0.10 M HNO$$_{3}$$ decrease with increasing concentration of the fluoride ion [F$$^{-}$$], indicating the consecutive formation of fluorido complexes of Rf. We also measured the $$K_{d}$$ values of Rf and the homologues as a function of the hydrogen ion concentration [H$$^{+}$$]. The log $$K_{d}$$ values decrease linearly with an increase of log [H$$^{+}$$] with slopes between -2.1 and -2.5. This indicates that these elements are likely to form the same chemical compounds: mixture of [MF]$$^{3+}$$ and [MF$$_{2}$$]$$^{2+}$$ (M = Rf, Zr, Hf and Th) in the studied solution. It is also ascertained that sequence in the fluoride complex formation is Zr $$sim$$ Hf $$>$$ Rf $$>$$ Th.

Journal Articles

Polarization-analyzed resonant inelastic X-ray scattering of the orbital excitations in KCuF$$_3$$

Ishii, Kenji; Ishihara, Sumio*; Murakami, Yoichi*; Ikeuchi, Kazuhiko*; Kuzushita, Kaori*; Inami, Toshiya; Owada, Kenji; Yoshida, Masahiro; Jarrige, I.; Tatami, Naka*; et al.

Physical Review B, 83(24), p.241101_1 - 241101_4, 2011/06

 Times Cited Count:18 Percentile:30.21(Materials Science, Multidisciplinary)

Journal Articles

Neutron one-quasiparticle states in $$^{251}$$Fm$$_{151}$$ populated via the $$alpha$$ decay of $$^{255}$$No

Asai, Masato; Tsukada, Kazuaki; Haba, Hiromitsu*; Ishii, Yasuo; Ichikawa, Takatoshi*; Toyoshima, Atsushi; Ishii, Tetsuro; Nagame, Yuichiro; Nishinaka, Ichiro; Kojima, Yasuaki*; et al.

Physical Review C, 83(1), p.014315_1 - 014315_12, 2011/01

 Times Cited Count:19 Percentile:19.41(Physics, Nuclear)

Excited states in $$^{251}$$Fm populated via the $$alpha$$ decay of $$^{255}$$No are studied in detail through $$alpha$$-$$gamma$$ coincidence and $$alpha$$ fine structure measurements. Spin-parities and neutron configurations of the excited states in $$^{251}$$Fm as well as the ground state of $$^{255}$$No are definitely identified on the basis of deduced internal conversion coefficients, lifetimes of $$gamma$$ transitions, rotational-band energies built on one-quasiparticle states, and hindrance factors of $$alpha$$ transitions. It is found that the excitation energy of the 1/2$$^{+}$$[620] state in $$N$$=151 isotones increases with the atomic number, especially at $$Z$$$$ge$$100, while that of the 1/2$$^{+}$$[631] state decreases at $$Z$$=100. Energy systematics of the one-quasiparticle states in the $$N$$=151 isotones are discussed in terms of the evolution of nuclear deformation involving the hexadecapole and hexacontatetrapole deformations.

Journal Articles

Resonant inelastic X-ray scattering of La$$_2$$Cu$$_{0.95}$$Ni$$_{0.05}$$O$$_4$$

Ishii, Kenji; Ikeuchi, Kazuhiko*; Jarrige, I.; Mizuki, Junichiro; Hiraka, Haruhiro*; Yamada, Kazuyoshi*; Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi*; Endo, Yasuo*; et al.

Physica C, 470(Suppl.1), p.S155 - S157, 2010/12

 Percentile:100(Physics, Applied)

Journal Articles

Temperature dependence of the electronic structure of Sr$$_{14}$$Cu$$_{24}$$O$$_{41}$$ studied by resonant inelastic X-ray scattering

Yoshida, Masahiro; Ishii, Kenji; Ikeuchi, Kazuhiko*; Jarrige, I.; Murakami, Yoichi*; Mizuki, Junichiro; Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi*; Kudo, Kazutaka*; et al.

Physica C, 470(Suppl.1), p.S145 - S146, 2010/12

 Times Cited Count:4 Percentile:73.14(Physics, Applied)

Journal Articles

Magnetic and dielectric study of R$$_{0.5}$$Sr$$_{0.5}$$MnO$$_{3}$$ (R = Gd, Tb and Dy)

Yoshii, Kenji; Hiramitsu, Yusuke*; Okajima, Yuka*; Yoneda, Yasuhiro; Nishihata, Yasuo; Mizuki, Junichiro; Nakamura, Akio; Shimojo, Yutaka; Ishii, Yoshinobu*; Morii, Yukio; et al.

Materials Research Bulletin, 45(11), p.1574 - 1580, 2010/10

 Times Cited Count:9 Percentile:61.93(Materials Science, Multidisciplinary)

Magnetic and dielectric properties of perovskite manganites R$$_{0.5}$$Sr$$_{0.5}$$MnO$$_{3}$$ (R = Gd, Tb and Dy) have been investigated. DC and AC magnetic measurements showed short-range glassy magnetic ordering at Tg about 40 K. Such ordering was observed by neutron diffraction and is ascribable to the size mismatch of R$$^{3+}$$ and Sr$$^{3+}$$ settled randomly at the same crystallographic site. Dielectric constants for each material were about 1000-10000 between about 50 K and 300 K and showed broad maximums above Tg. Dielectric dispersion showed poor coherency of the motion of polar regions, plausibly because of the size-mismatch effect; both the magnetic and dielectric properties of this system are governed by the randomness at the R/Sr site. The tan$$delta$$ and EXAFS data suggest that the dielectric response is rooted in a transfer of the Mn-3d electrons.

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