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Journal Articles

Hydrological and climate changes in southeast Siberia over the last 33 kyr

Katsuta, Nagayoshi*; Ikeda, Hisashi*; Shibata, Kenji*; Kokubu, Yoko; Murakami, Takuma*; Tani, Yukinori*; Takano, Masao*; Nakamura, Toshio*; Tanaka, Atsushi*; Naito, Sayuri*; et al.

Global and Planetary Change, 164, p.11 - 26, 2018/05

 Times Cited Count:8 Percentile:44.36(Geography, Physical)

Paleoenvironmental and paleoclimate changes in Siberia were reconstructed by continuous, high-resolution records of chemical compositions from a sediment core retrieved from the Buguldeika Saddle, Lake Baikal, dating back to the last 33 cal. ka BP. The Holocene climate followed by a shift at ca. 6.5 cal. ka BP toward warm and dry, suggesting that the climate system transition from the glacial to interglacial state occurred. In the last glacial period, the deposition of carbonate mud from the Primorsky Range was associated with Heinrich events (H3 and H1) and the Selenga River inflow was caused by meltwater of mountain glaciers in the Khamar-Daban Range. The anoxic bottom-water during Allerod-Younger Dryas was probably a result of weakened ventilation associated with reduced Selenga River inflow and microbial decomposition of organic matters from the Primorsky Range. The rapid decline in precipitation during the early Holocene may have been a response to the 8.2 ka cooling event.

Journal Articles

Cesium adsorption ability and stability of metal hexacyanoferrates irradiated with $$gamma$$-rays

Arisaka, Makoto; Watanabe, Masayuki; Ishizaki, Manabu*; Kurihara, Masato*; Chen, R.*; Tanaka, Hisashi*

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1543 - 1547, 2015/02

 Times Cited Count:12 Percentile:70.84(Chemistry, Analytical)

The influence of irradiation with $$gamma$$-rays to metal hexacyanoferrate (MHCF: M = Fe, Cu or Ni), which is known as an adsorbent for selective adsorption of cesium (Cs) ion in solution, on Cs adsorption ability and stability was investigated in HNO$$_{3}$$ solutions. Under the adsorbed dose conditions (50-300 kGy), it was found that the MHCF is fully stable although the radiolytic decomposition of MHCF was slightly observed with an increase of the total adsorbed dose, which was confirmed by an increment of Fe, Cu or Ni concentration in HNO$$_{3}$$ solution after the irradiation. The weight percent of the metal in the solution to initial weight of MHCF was less than unity. Moreover, no change in composition of carbon, hydrogen and nitrogen in MHCF was observed. On the other hand, the distribution coefficients of Cs to the irradiated MHCF were independent of the total adsorbed dose. This indicates that the Cs adsorption ability was maintained under $$gamma$$-ray irradiation.

Journal Articles

Geochemical and grain-size distribution of radioactive and stable cesium in Fukushima soils; Implications for their long-term behavior

Saito, Takumi; Makino, Hisashi*; Tanaka, Satoru*

Journal of Environmental Radioactivity, 138, p.11 - 18, 2014/12

 Times Cited Count:64 Percentile:86.61(Environmental Sciences)

Radioactive cesium was predominantly found in the extract obtained by strong-acid dissolution and the extraction residue and was more concentrated in silt and clay grains. X-ray diffraction analyses revealed that micaceous minerals as well as kaolin minerals were predominantly dissolved by the strong-acid treatment. Correlation between the fraction of $$^{137}$$Cs and the content of micaceous minerals in different grain-size fractions of soil minerals suggests that micaceous minerals are responsible for the fixation of $$^{137}$$Cs in the soils. The isotopic ratio of $$^{137}$$Cs and $$^{133}$$Cs in the extract by strong-acid dissolution was more than three times smaller than those in the extracts by water, ion exchange, and reductive dissolution. This indicates that the distribution of $$^{137}$$Cs was not in the steady state in 2 y after the accident due to relatively slow fixation by the soil clay minerals.

Journal Articles

Proton-exchange mechanism of specific Cs$$^{+}$$ adsorption $$via$$ lattice defect sites of Prussian blue filled with coordination and crystallization water molecules

Ishizaki, Manabu*; Akiba, Sae*; Otani, Asako*; Hoshi, Yuji*; Ono, Kenta*; Matsuba, Mayu*; Togashi, Takanari*; Kanaizuka, Katsuhiko*; Sakamoto, Masatomi*; Takahashi, Akira*; et al.

Dalton Transactions, 42(45), p.16049 - 16055, 2013/12

 Times Cited Count:165 Percentile:99.56(Chemistry, Inorganic & Nuclear)

We have revealed the fundamental mechanism of specific Cs$$^{+}$$ adsorption into Prussian blue (PB) in order to develop high-performance PB-based Cs$$^{+}$$ adsorbents in the wake of the Fukushima nuclear accident. We compared two types of PB nanoparticles with formulae of Fe$$^{III}$$$$_{4}$$[Fe$$^{II}$$(CN)$$_{6}$$]3$$cdot$$xH$$_{2}$$O (x = 10-15) (PB-1) and (NH$$_{4}$$)0.70Fe$$^{III}$$1.10[Fe$$^{II}$$(CN)$$_{6}$$]$$cdot$$1.7H$$_{2}$$O (PB-2) with respect to the Cs$$^{+}$$ adsorption ability. The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe$$^{3+}$$ and 3[Fe$$^{II}$$(CN)$$_{6}$$]$$^{4-}$$, showed much more efficient Cs$$^{+}$$ adsorption ability than did the commercially available PB-2.

Journal Articles

Selective removal of cesium ions from wastewater using copper hexacyanoferrate nanofilms in an electrochemical system

Chen, R.*; Tanaka, Hisashi*; Kawamoto, Toru*; Asai, Miyuki*; Fukushima, Chikako*; Na, H.*; Kurihara, Masato*; Watanabe, Masayuki; Arisaka, Makoto; Nankawa, Takuya

Electrochimica Acta, 87, p.119 - 125, 2013/01

 Times Cited Count:104 Percentile:94.98(Electrochemistry)

A novel electrochemical adsorption system using a nanoparticle film of copper (II) hexacyanoferrate (III) was proposed for selectively removing cesium from wastewater. This system can be used for cesium separation without extra chemical reagents or any filtration treatment. Cesium uptake and elution can be simply controlled by switching the applied potentials between anodes and cathodes. Data from batch kinetic studies well fitted the intraparticle diffusion equation, reflecting a two-step process: a steepest ascent portion followed by a plateau extending to the equilibrium. The effective cesium removal with a high distribution coefficient ($$K$$$$_{d}$$ $$>$$ 5$$times$$10$$^{5}$$ mL/g) can be adopted in a large pH range from 0.3 to 9.2, and in the presence of several diverse coexisting alkaline cations, suggesting it can be taken as a promising technology for actual nuclear wastewater treatment.

Journal Articles

Preparation of a film of copper hexacyanoferrate nanoparticles for electrochemical removal of cesium from radioactive wastewater

Chen, R.*; Tanaka, Hisashi*; Kawamoto, Toru*; Asai, Miyuki*; Fukushima, Chikako*; Kurihara, Masato*; Watanabe, Masayuki; Arisaka, Makoto; Nankawa, Takuya

Electrochemistry Communications, 25, p.23 - 25, 2012/11

 Times Cited Count:49 Percentile:79.98(Electrochemistry)

We first synthesized water-dispersed nanoparticle copper hexacyanoferrate (CuHCF) ink and then coated its nanoparticles on electrodes to electrochemically remove cesium from wastewater. Cesium uptake and elution can be controlled by switching the potentials between anodes and cathodes. Effective cesium removal can be adopted in a large pH range from 0.2 to 8.9, and in the presence of several diverse coexisting alkaline cations, suggesting that it can be taken as a promising technology for actual radioactive wastewater treatment. The prepared CuHCF nanoparticles can be simply and uniformly coated on electrodes by wet process like conventional printing methods, so any sizes or patterns are feasible at low cost, which indicated the potential as a promising sorption electrode of large size in the columns for sequential removal and recycle of Cs from wastewater.

Journal Articles

Packing behaviour of a Li$$_{2}$$TiO$$_{3}$$ pebble bed under cyclic loads

Tanigawa, Hisashi; Tanaka, Yuichiro*; Enoeda, Mikio

Journal of Nuclear Materials, 417(1-3), p.703 - 705, 2011/10

 Times Cited Count:5 Percentile:38.79(Materials Science, Multidisciplinary)

In the temperature range from room temperature to 973 K and the mechanical loading range from 0.1 MPa to 3 MPa, Li$$_{2}$$TiO$$_{3}$$ pebble bed is successively loaded and the packing behaviour of the bed is observed. Deformation caused by the mechanical loadings is partly relaxed when the bed is heated without the load. After large numbers of thermal and mechanical loadings, the packing factor of the bed with the initial packing factor of 66.9% finally reaches about 68.5%. The progress of packing leads to production of a void region at the top of the pebble bed and it is important to obtain a high packing factor for the initial packing.

Journal Articles

Thermal conductivity measurement with silica-coated hot wire for Li$$_4$$SiO$$_4$$ pebble bed

Tanigawa, Hisashi; Tanaka, Yuichiro*; Enoeda, Mikio; Akiba, Masato

Journal of Nuclear Science and Technology, 46(6), p.553 - 556, 2009/06

 Times Cited Count:6 Percentile:41.12(Nuclear Science & Technology)

Effective thermal conductivity of a Li$$_4$$SiO$$_4$$ pebble bed was measured by the hot wire method. The bare and the silica-coated Nichrome heaters were used as the hot wire. At 975 K, the effective thermal conductivity was not measured correctly by the bare hot wire. This is caused by that the electrical signal of the bare thermocouple is distorted due to electrical conductivity of Li$$_4$$SiO$$_4$$. Using the silica-coated hot wire, the effective thermal conductivity can be measured at temperatures ranging from room temperature to 975 K. The effect of the coating layer on the measured effective thermal conductivity was estimated to be small and corresponded to the experimental data. The hot wire method with silica-coating can be applied to the other ceramic breeder materials.

Journal Articles

Muon spin rotation study of magnetism in multilayer HgBa$$_2$$Ca$$_4$$Cu$$_5$$O$$_y$$ superconductor

Tokiwa, Kazuyasu*; Mikusu, Satoshi*; Higemoto, Wataru; Nishiyama, Kusuo*; Iyo, Akira*; Tanaka, Yasumoto*; Kotegawa, Hisashi*; Mukuda, Hidekazu*; Kitaoka, Yoshio*; Watanabe, Tsuneo*

Physica C, 460-462(2), p.892 - 895, 2007/09

 Times Cited Count:3 Percentile:17.92(Physics, Applied)

Zero- and longitudinal-field muon-spin rotation (ZF-$$mu$$SR and LF-$$mu$$SR) measurements were carried out on a multi-layered HgBa$$_2$$Ca$$_4$$Cu$$_5$$O$$_y$$ (Hg-1245) superconductor with $$T$$$$_{rm c}$$ of 108 K. With decreasing temperature, the observed ZF-$$mu$$SR function changed from a Gaussian-type to an exponential-type below 60 K and zero field muon precession was also observed below 45 K. These $$mu$$SR signals are attributed to the development of the antiferromagnetic ordering in inner CuO$$_2$$planes with a low carrier concentration. These results seem to indicate clear evidence that antiferromagnetism microscopically coexists with superconductivity in the Hg-1245 superconductor below 60 K.

Journal Articles

Study of stellar reactions in explosive hydrogen burning with CRIB

Kubono, Shigeru*; Teranishi, Takashi*; Notani, Masahiro*; Yamaguchi, Hidetoshi*; Saito, Akito*; He, J. J.*; Wakabayashi, Yasuo*; Fujikawa, Hisashi*; Amadio, G.*; Baba, Hidetada*; et al.

Nuclear Physics A, 758, p.733 - 736, 2005/07

 Times Cited Count:1 Percentile:14.46(Physics, Nuclear)

With using $$^{17}F$$ RNB from CRIB, proton inelastic scattering was observed. From this experiment, some resonance parameters have been deduced for the key reaction, $$^{14}O(alpha,p)^{17}F$$ at the explosive hydrogen burning stage in stars. Proton inelastic scattering of $$^{23}Mg$$ are also reported.

Journal Articles

FT-IR study on interaction of irradiated deuteron with defects in Li$$_{2}$$O

Tanigawa, Hisashi; Tanaka, Satoru*; Enoeda, Mikio; Akiba, Masato

Journal of Nuclear Materials, 329-333(2), p.1291 - 1294, 2004/08

 Times Cited Count:4 Percentile:29.31(Materials Science, Multidisciplinary)

In order to elucidate the interaction of hydrogen isotopes with irradiation defects, infrared absorption spectroscopy was conducted for a single crystal of Li$$_{2}$$O. Using FT-IR, O-D stretching vibration from the bulk Li$$_{2}$$O was observed under deutron irradiation. Under and after the irradiation, several peaks were observed in the O-D stretching vibration region and these peaks had different dependence on conditions of the irradiation. From the observed behaviour of the peaks, it was suggested that most of the irradiated deutron existed in Li$$_{2}$$O without O-D bonding because of interaction with the defects.

Journal Articles

Beam commissioning of the J-PARC linac DTL1 at KEK

Kondo, Yasuhiro; Akikawa, Hisashi; Anami, Shozo*; Asano, Hiroyuki*; Fukui, Yuji*; Igarashi, Zenei*; Ikegami, Kiyoshi*; Ikegami, Masanori*; Ito, Takashi; Kawamura, Masato*; et al.

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.156 - 158, 2004/08

A commissioning of the J-PARC linac DTL1 is now under way at KEK. A 30mA H$$^{-}$$ beam was accelerated to 19.7-MeV, and 100% transmission was obtained with a 20-msec-pulse-width and 12.5-Hz-repetition beam. In this paper, present status of the DTL1 commissioning and preliminary results of the commissioning, such as emittance measurements, are presented.

Journal Articles

Systematic calibration of beam position monitor at J-PARC LINAC

Sato, Susumu; Tomisawa, Tetsuo; Hiroki, Fumio; Lee, S.*; Igarashi, Zenei*; Ikegami, Masanori*; Ueno, Akira; Kondo, Yasuhiro; Hasegawa, Kazuo; Toyama, Takeshi*; et al.

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.467 - 469, 2004/08

As a joint project of KEK and JAERI, a MW class of high intensity proton accelerator (J-PARC), consisting of Linac, 3 GeV-RCS, 50 GeV-MR, is under construction. For this accelerator, it is required to minimize the beam loss (typically, lower than0.1$$sim$$1 W/m at the linac). To achieve the requirement, beam trajectory needs to be controlled with accuracy of some 100 $$mu$$m. The first stage of the acceleration (up to 181 MeV during the first stage of construction) is done by linac. The beam position monitor (BPM) in the linac utilizes 4 stripline pickups (50 ohm) on the beam transportation chamber. In this paper, systematic calibration of the BPM is described.

JAEA Reports

Research about the long-term stability of TRU waste disposal system

Tanaka, M.*; Fujisawa, O.*; Okutsu, Kazuo*; Takamura, Hisashi*; Aoyagi, Takayoshi*

JNC TJ8400 2001-031, 70 Pages, 2001/02

JNC-TJ8400-2001-031.pdf:6.27MB

no abstracts in English

JAEA Reports

Research about the long-term stability of TRU waste disposal system

Tanaka, M.*; Fujisawa, O.*; Okutsu, Kazuo*; Takamura, Hisashi*; Aoyagi, Takayoshi*

JNC TJ8400 2001-030, 82 Pages, 2001/02

JNC-TJ8400-2001-030.pdf:13.47MB

This research arranged the relation with the events (the events which happen to each part grade of disposal institution and change) produced to the characteristic in connection with low permeability and the disposal system of barrier material, such as permeability. The important events which can affect the long stability of the performance which barrier material has by that cause, and its relation were extracted. And, the physical-properties data acquisition of bentonite supposing the events considered to be generated to a disposal system in the future was carried out. The research result of this year is shown below. (1)About the events considered to affect permeability, "the present knowledge and the reseach result" and the "view of a design about a event" were arranged. And it divided and arranged the time of construction and operation, and after closure. Consequently, the subject required in order to check the long stability of TRU waste disposal system was able to be extracted. (2)In order for the research in the last year to estimate the self-seal nature of a bentonite, swelling pressure and the permeability at the time of the bentonite which generated the maximum swelling pressure under the restricted condition for Na-bentonite and Ca-bentonite 100% material re-swelling to the space produced after that were acquired. About this result, the view of effective bentonite dryness density was applied, and the self-seal performance of the assumed material (bentonite 70%, silica 30%) examined in TRU waste disposal concept examination document was evaluated. In order to check the validity of the evaluation in the last year, the self-seal performance check experiment was conducted about the silica mixture bentonite. Consequently, the soundness of a barrier system was able to be checked by the specification of H12 TRU report.

Journal Articles

Integrated experiment of blanket in-pile mockup with Li$$_{2}$$TiO$$_{3}$$ pebbles

Tsuchiya, Kunihiko; Nakamichi, Masaru; Nagao, Yoshiharu; Fujita, J.*; Sagawa, Hisashi; Tanaka, Satoru*; Kawamura, Hiroshi

Fusion Engineering and Design, 51-52, p.887 - 892, 2000/11

 Times Cited Count:15 Percentile:70.46(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

A Study of disposal concept for TRU waste, 5; A Study on the mechanical properties of engineered barrier materials

Tanaka, M.*; Yamamoto, H.*; Fujisawa, O.*; Okutsu, Kazuo*; Miura, K.*; Takamura, Hisashi*

JNC TJ8400 2000-036, 196 Pages, 2000/02

JNC-TJ8400-2000-036.pdf:23.76MB

TRU waste should be isolated from biosphere for a long period of time as it includes long lived nuclides. In this study, (1) data were conected on the mechanical properties of engineered barrier materials, (2) affection on the mechanical properties of Na bentonito by salt water was studied and (3) soundness of the disposal system against changes in the volume of engineered banier was evaluated, to examine critical events related to the long-term soundness of the disposal system. Described below are the results of the studies. (1) The swelling pressure, swelling amount and permeability were obtained for a material consisting of NaCa-exchanged bentonito and silica sand with a relative weight of 30% (with a dry density of 1.6 Mgm$$^{-3}$$) by supplying saturated calcium hydroxide aqeous solution. As a result, it was confirmed that the swelling pressure and permeability were approximately estimated from the relation between these properties and the effective dry density of bentonito. (2) The swelling pressure, swelling amount and permeability were obtained for a material consisting of salty Na bentonito and silica sand with a relative weight of 30% (with a dry density of 1.6 Mgm$$^{-3}$$) by supplying artifical salt water. As a result, it was confirmed that these properties were approximately these properties of NaCa-bentonito. (3) Tests were conducted as a part of the evaluation of system soundness against changes in the volume of engineered barrier. Development of a void around bentonito was assumed. Self sealing of Na and NaCa-exchanged bentonito, and theirs water cut-off capability and swelling pressure were investigated.As a result, it was confirmed that the change of permeability and swelling pressure under self sealing of bentonito. Based on the test results (i.e. the both relations between the swelling pressure and dry density, and the permeability and dry density), soundness of the system was verified against changes of the volume of engineered barrier materials.

JAEA Reports

A Study of disposal concept for TRU waste, 5; Adtudy on the mechanical properties of engineered barrier materials

Tanaka, M.*; Yamamoto, H.*; Fujisawa, O.*; Okutsu, Kazuo*; Miura, K.*; Takamura, Hisashi*

JNC TJ8400 2000-035, 59 Pages, 2000/02

JNC-TJ8400-2000-035.pdf:8.87MB

no abstracts in English

Journal Articles

Results and outline of JPDR dismantling demonstration project

Miyasaka, Yasuhiko; ; Tanaka, Mitsugu; Nakamura, Hisashi; ; Tachibana, Mitsuo; ; Hatakeyama, Mutsuo; ; Yoshimori, Michiro; et al.

Nihon Genshiryoku Gakkai-Shi, 38(7), p.553 - 576, 1996/00

no abstracts in English

Journal Articles

Design of High Temperature Engineering Test Reactor(HTTR) and associated resarch and development

Saito, Shinzo; Tanaka, Toshiyuki; Sudo, Yukio; Baba, Osamu; ; Hishida, Makoto; ; ; Shinohara, Yoshikuni; *; et al.

Nihon Genshiryoku Gakkai-Shi, 32(9), p.847 - 871, 1990/09

no abstracts in English

32 (Records 1-20 displayed on this page)