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Journal Articles

Determination of local-area distribution and relocation of radioactive cesium in trees from Fukushima Daiichi Nuclear Power Plant by autoradiography analysis

Sakamoto, Fuminori; Onuki, Toshihiko; Kozai, Naofumi; Yamasaki, Shinya; Yoshida, Zenko*; Namba, Kenji*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(4), p.257 - 266, 2013/12

no abstracts in English

Journal Articles

Decontamination of outdoor school swimming pools in Fukushima after the nuclear accident in March 2011

Saegusa, Jun; Kurikami, Hiroshi; Yasuda, Ryo; Kurihara, Kazuo; Arai, Shigeki; Kuroki, Ryota; Matsuhashi, Shimpei; Ozawa, Takashi; Goto, Hiroaki; Takano, Takao; et al.

Health Physics, 104(3), p.243 - 250, 2013/03

 Times Cited Count:3 Percentile:27.41(Environmental Sciences)

After the Nuclear accident on March 2011, water discharge from many outdoor swimming pools in the Fukushima prefecture was suspended out of concern that radiocesium in the pool water would flow into farmlands. We have reviewed the existing flocculation method for decontaminating pool water and established a practical decontamination method by demonstrating the process at several pools in the Fukushima prefecture.

Journal Articles

Method for monitoring radioactive cesium concentration in water using cesium adsorption disk and GM survey meter

Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yoshida, Zenko; Yamaguchi, Hiroaki*

Nihon Hoshasen Anzen Kanri Gakkai-Shi, 11(2), p.139 - 145, 2012/11

An on-site monitoring method for radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to rapidly and easily ascertain whether the water quality meets standards on radiological contaminants in water. In this method, both dissolved and suspended forms of radioactive cesium are collected on the cesium adsorption disk by means of filtration of a water sample. Beta counting rate of the disk is converted into radioactivity using a conservative calibration factor obtained here. The present on-site method was applied to monitoring of decontaminated water of an outdoor school swimming pool in Date city after Fukushima Dai-ichi Nuclear Power Plant accident.

Journal Articles

Local area distribution of fallout radionuclides from Fukushima Daiichi Nuclear Power Plant determined by autoradiography analysis

Sakamoto, Fuminori; Onuki, Toshihiko; Kozai, Naofumi; Igarashi, Shosuke*; Yamasaki, Shinya; Yoshida, Zenko; Tanaka, Shunichi*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(1), p.1 - 7, 2012/01

The autoradiography analyses of plants and soils collected in Fukushima showed radioactive Cs was distributed on the branch and leaves of trees that were present at the accident and that only small fraction may be transported to new branch and leaves grown after the accident. Radioactive Cs was present on the grass and rice stubble on the soils, but not in the soils beneath the grass and rice stubble, indicating that the radioactive Cs was deposited on the grass and the rice plant. In addition the ratio of the radioactive Cs penetrated into soil layer by weathering was very small for two months after the accident. These results indicate that trees and plant would be the reservoir of the fallout Cs and function for retardation of the fallout Cs migration with rain water.

Journal Articles

Removal of radioactive cesium from surface soils solidified using polyion complex; Rapid communication for decontamination test at Iitate-mura in Fukushima Prefecture

Naganawa, Hirochika; Kumazawa, Noriyuki*; Saito, Hiroshi*; Yanase, Nobuyuki; Mitamura, Hisayoshi; Nagano, Tetsushi; Kashima, Kaoru*; Fukuda, Tatsuya*; Yoshida, Zenko; Tanaka, Shunichi*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.227 - 234, 2011/12

no abstracts in English

Journal Articles

Standard Gibbs free energies for transfer of actinyl ions at the aqueous/organic solution interface

Kitatsuji, Yoshihiro; Okugaki, Tomohiko*; Kasuno, Megumi*; Kubota, Hiroki*; Maeda, Koji*; Kimura, Takaumi; Yoshida, Zenko; Kihara, Sorin*

Journal of Chemical Thermodynamics, 43(6), p.844 - 851, 2011/06

 Times Cited Count:7 Percentile:28.51(Thermodynamics)

Standard Gibbs energies for transfer ($$Delta$$G$$_{tr}$$$$^{0}$$) of actinyl ions (AnO$$_{2}$$$$^{z+}$$; z = 2 or 1; An: U, Np or Pu) between an aqueous solution and an organic solution were determined based on distribution method combined with voltammetry for ion transfer at the interface of two immiscible electrolyte solutions. The organic solutions examined were nitrobenzene, 1,2-dichloroethane, benzonitrile, acetophenone and 2-nitrophenyl octyl ether. Irrespective of the type of organic solutions, $$Delta$$G$$_{tr}$$$$^{0}$$ of UO$$_{2}$$$$^{2+}$$, NpO$$_{2}$$$$^{2+}$$ and PuO$$_{2}$$$$^{2+}$$ were nearly equal to each other and slightly larger than that of Mg$$^{2+}$$. The $$Delta$$G$$_{tr}$$$$^{0}$$ of NpO$$_{2}$$$$^{+}$$ was extraordinary large compared with those of ordinary monovalent cations. The dependence of $$Delta$$G$$_{tr}$$$$^{0}$$ of AnO$$_{2}$$$$^{z+}$$ on the type of organic solutions was similar to that of H$$^{+}$$ or Mg$$^{2+}$$. The $$Delta$$G$$_{tr}$$$$^{0}$$ of An$$^{3+}$$ and An$$^{4+}$$ were also discussed briefly.

Journal Articles

Development of high performance electrochemical solvent extraction method

Okugaki, Tomohiko*; Kitatsuji, Yoshihiro; Kasuno, Megumi*; Yoshizumi, Asuka*; Kubota, Hiroki*; Shibafuji, Yayoi*; Maeda, Koji*; Yoshida, Zenko; Kihara, Sorin*

Journal of Electroanalytical Chemistry, 629(1-2), p.50 - 56, 2009/04

A high performance electrochemical solvent extraction method was developed based on the quantitative transfer of ions from an aqueous, W, to an organic solution, O. It was realized by applying a potential difference between W and O. The cell was composed of a porous Teflon tube immersed with O, a Ag wire inserted into the tube, a Pt wire placed outside the tube. When W containing ions was forced to flow through the narrow gap between the tube and Ag wire, and potential was applied, a very rapid quantitative ion transfer was attained. When O containing extractant, more than 99% of U(VI) in W was extracted during the residence (e.g., 40 s) in the cell. The fundamental feature of the extraction system was investigated, taking into account the application of the system to the extraction of actinide, lanthanide, Sr or Cs ions. The use of a column electrode system connected before the extraction system was examined in order to adjust the oxidation state of the element to that desired.

JAEA Reports

Recent progress of analytical methods of spent nuclear fuel, Review

Yoshida, Zenko; Watanabe, Kazuo; Ito, Mitsuo; Ueno, Takashi; Takeshita, Hidefumi

JAEA-Review 2008-062, 34 Pages, 2009/01


Analytical methods for the spent nuclear fuel (SF) have been greatly innovated recently. This methodological innovation is mainly caused by rapid and remarkable progress of induced coupled plasma-mass spectrometry (ICP-MS) which is utilized for the isotopic analysis of actinoid elements (U, Np, Pu, Am, Cm) and fission product elements in the SF samples. The quantity of the objective element as well as the volume of the sample solution needed for the ICP-MS measurement are, in principle, much less than those required for the measurement by other analytical methods. ICP-MS makes it possible to reduce the radiation dose of the operator and to minimize the amount of the radioactive wastes generated from the analytical work. For the precise and accurate isotopic analysis of the objective element in the SF sample by mass spectrometry, the interfering element having isobars needs to be separated prior to the measurement. This review highlights the development of the separation methods and isotopic analysis methods for the analysis of the SF based on more than 50 recent publications and the future problems to be solved and prospects are discussed.

Journal Articles

Hydrogen production in the $$gamma$$-radiolysis of aqueous sulfuric acid solutions containing Al$$_{2}$$O$$_{3}$$, SiO$$_{2}$$, TiO$$_{2}$$ or ZrO$$_{2}$$ fine particles

Yamada, Reiji; Nagaishi, Ryuji; Hatano, Yoshihiko; Yoshida, Zenko

International Journal of Hydrogen Energy, 33(3), p.929 - 936, 2008/02

 Times Cited Count:15 Percentile:37.88(Chemistry, Physical)

Hydrogen production was studied in the $$gamma$$-radiolysis of aqueous H$$_{2}$$SO$$_{4}$$ solutions containing oxide powder of Al$$_{2}$$O$$_{3}$$, SiO$$_{2}$$, TiO$$_{2}$$ or ZrO$$_{2}$$. The observed yields of final product H$$_{2}$$ increased with relative amounts of oxide powder in the solutions and exhibited a particular H$$_{2}$$SO$$_{4}$$ concentration dependence, which was different for each oxide species and its amount. The addition of a small amount of CH$$_{3}$$OH to a H$$_{2}$$SO$$_{4}$$ aqueous solution with oxide powder was quite effective for increasing the final product yields of H$$_{2}$$. The obtained results revealed that heterogeneous systems composed of oxide powder and aqueous H$$_{2}$$SO$$_{4}$$ solution were more efficient for producing H$$_{2}$$ molecules in $$gamma$$-radiolysis than homogeneous systems without oxides.

Journal Articles

Electrochemical evaluation of the distribution of a metal ion at the aqueous$$|$$organic solution interface in chelate extraction

Uehara, Akihiro*; Kasuno, Megumi*; Okugaki, Tomohiko*; Kitatsuji, Yoshihiro; Shirai, Osamu*; Yoshida, Zenko; Kihara, Sorin*

Journal of Electroanalytical Chemistry, 604(2), p.115 - 124, 2007/06

The distribution ratio of a metal ion between an aqueous solution and an organic solution in solvent extraction with a chelating agent was evaluated by using physicochemical constants determined electrochemically such as standard Gibbs energies for transfers of the ions, the overall complex formation constants and the acid dissociation constants of the chelating agent. The distribution ratio thus evaluated agreed well with those determined by the distribution experiment.

Journal Articles

Radiation-induced catalytic reduction of chromium(VI) in aqueous solution containing TiO$$_{2}$$, Al$$_{2}$$O$$_{3}$$ or SiO$$_{2}$$ fine particles

Nagaishi, Ryuji; Yoshida, Zenko; Yamada, Reiji; Hatano, Yoshihiko

Radiation Physics and Chemistry, 75(9), p.1051 - 1054, 2006/09

 Times Cited Count:7 Percentile:46.78(Chemistry, Physical)JP, H17-065162   Licensable Patent Information Database   Patent publication (In Japanese)

Reduction of chromium(VI) in aqueous neutral or basic solution was promoted by $$gamma$$-ray irradiation in the presence of oxide particles such as TiO$$_{2}$$, Al$$_{2}$$O$$_{3}$$ or SiO$$_{2}$$. The oxide particles behaved as a catalyst, and the efficiency of the Cr(VI) reduction increased with an increase of the irradiation dose irrespective of the initial Cr(VI) concentration. The insoluble Cr(III) oxide formed through the Cr(VI) reduction also acted as the catalyst.

Journal Articles

Curium(III) species and the coordination states in concentrated LiCl-aqueous solutions studied by time-resolved laser-induced fluorescence spectroscopy

Arisaka, Makoto; Kimura, Takaumi; Nagaishi, Ryuji; Yoshida, Zenko

Journal of Alloys and Compounds, 408-412, p.1307 - 1311, 2006/02

 Times Cited Count:6 Percentile:43.56(Chemistry, Physical)

no abstracts in English

Journal Articles


Yoshida, Zenko; Johnson, S. G.*; Kimura, Takaumi; Krsul, J. R.*

Chemistry of the Actinide and Transactinide Elements, Vol.2, p.699 - 812, 2006/00

no abstracts in English

Journal Articles

Rapid and coulometric electrolysis for ion transfer at the aqueous|organic solution interface

Yoshizumi, Asuka*; Uehara, Akihiro*; Kasuno, Megumi*; Kitatsuji, Yoshihiro; Yoshida, Zenko; Kihara, Sorin*

Journal of Electroanalytical Chemistry, 581(2), p.275 - 283, 2005/08

no abstracts in English

Journal Articles

Rapid and quantitative electrolytic preparation and speciation of neptunium ions of various oxidation states using multi-step column electrodes

Aoyagi, Hisao*; Kitatsuji, Yoshihiro; Yoshida, Zenko; Kihara, Sorin*

Analytica Chimica Acta, 538(1-2), p.283 - 289, 2005/05

 Times Cited Count:14 Percentile:40.49(Chemistry, Analytical)

Redox behavior of Np(III), (IV), (V) and (VI) ions in aqueous perchloric, nitric and sulphuric acid solutions was elucidated by using column electrodes connected in series in a flow system. Using a glassy carbon fiber working electrode as the column electrode was found to be very useful for the investigation of current-potential relations of not only reversible redox processes such as Np(VI)/(V) or Np(IV)/(III) but also irreversible processes such as Np(V)/(IV) or Np(V)/(III), the latter not observed by conventional voltammetry which uses a glassy carbon or platinum electrode. Quantitative electrolysis could be executed even if the redox process was completely irreversible by the use of the column electrodes. By taking advantage of column electrode electrolysis, a novel method was developed for the rapid preparation of a neptunium species of a desired oxidation state, including unstable species. The multi-step column electrode system was demonstrated to be useful for the coulometric determination and speciation of Np(IV), (V) and (VI) in aqueous HNO$$_{3}$$ solution as an example.

Journal Articles

Speciation study on complex formation of uranium(VI) with phosphate and fluoride at high temperatures and pressures by time-resolved laser-induced fluorescence spectroscopy

Kirishima, Akira; Kimura, Takaumi; Tochiyama, Osamu*; Yoshida, Zenko

Radiochimica Acta, 92(12), p.889 - 896, 2005/01

 Times Cited Count:24 Percentile:80.99(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Luminescence study of lanthanide(III) ions in non-aqueous solutions containing azide ions

Lis, S.*; Kimura, Takaumi; Yoshida, Zenko; But, S.*

Journal of Alloys and Compounds, 380(1-2), p.173 - 176, 2004/10

 Times Cited Count:6 Percentile:41.41(Chemistry, Physical)

no abstracts in English

Journal Articles

Fluorescence and IR studies on the hydration state of lanthanides(III) and curium(III) in the complexes extracted with purified Cyanex301, Cyanex302 and Cyanex272

Tian, G.*; Kimura, Takaumi; Yoshida, Zenko; Zhu, Y.*; Rao, L.*

Radiochimica Acta, 92(8), p.495 - 499, 2004/08

 Times Cited Count:16 Percentile:71.15(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Speciation study on uranium(VI) hydrolysis at high temperatures and pressures

Kirishima, Akira; Kimura, Takaumi; Tochiyama, Osamu*; Yoshida, Zenko

Journal of Alloys and Compounds, 374(1-2), p.277 - 282, 2004/07

 Times Cited Count:25 Percentile:74.51(Chemistry, Physical)

no abstracts in English

Journal Articles

Principle of electrolytic chromatography and coulopotentiography and its application to flow-injection analysis

Yoshida, Zenko; Kihara, Sorin*; Fujinaga, Taichiro*

Bunseki Kagaku, 53(4), p.195 - 205, 2004/04

 Times Cited Count:1 Percentile:1.01(Chemistry, Analytical)

A quantitative electrolysis of an electro-active species in a sample solution can be achieved very rapidly when the solution is allowed to flow through and be electrolyzed at a column electrode. Complete electrolysis of the species is attained with a small over-voltage, even if the electrode reaction is slow. The electrolytic method using the column electrode is suitable for automated or remote-controlled operation. Because of unmatched advantages, the column-electrode electrolysis method has been widely applied to the coulometric determination of species in a flowing sample solution and to liquid chromatography as a coulometric detector. This technique is especially favorable for elucidating mechanism of such complicated reactions as that involving unstable intermediates. In the present article, a principle and a feature of the column-electrode electrolysis are presented and the advantages of these methods are reviewed based on recent works on its application to flow-injection analysis and to a study of the redox reaction of actinide ions or the reaction of short-lived radicals.

107 (Records 1-20 displayed on this page)