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Journal Articles

The Chemistry of uranium (II); Method and practice

Sato, Nobuaki*; Kirishima, Akira*; Watanabe, Masayuki; Sasaki, Takayuki*; Uehara, Akihiro*; Takeda, Shino*

Uran No Kagaku (II); Hoho To Jissen, 143 Pages, 2021/03

This book describes necessary facts when readers would have an opportunity to treat Uranium for experiments. In the content, the method section shows experimental facilities and equipment including method, and the practical section mentions solution and solid state experiments using Uranium and/or radioisotopes.

Journal Articles

Investigation of chemical state of uranium included in simulated waste glass

Nagai, Takayuki; Akiyama, Daisuke*; Kirishima, Akira*; Sato, Nobuaki*; Okamoto, Yoshihiro

2019-Nendo "Busshitsu, Debaisu Ryoiki Kyodo Kenkyu Kyoten" Oyobi "Hito, Kankyo To Busshitsu O Tsunagu Inobeshion Soshutsu Dainamikku, Araiansu" Kenkyu Seika, Katsudo Hokokusho (CD-ROM), P. 20191107_1, 2020/11

no abstracts in English

Journal Articles

The Chemistry of uranium (I); Basics and application

Sato, Nobuaki*; Kirishima, Akira*; Watanabe, Masayuki

Uran No Kagaku (I); Kiso To Oyo, 184 Pages, 2020/06

This particular book deals with fundamental items related with chemistry of Uranium and consists of basic section and practical section. In the basic section, inorganic and radiochemistry of Uranium was described. On the other hand, in the practical section, the process chemistry related with reprocessing of nuclear fuels and "debris" involved with Fukushima Daiichi Power Plant accident were described. This book is intended for use by scientists, engineers and students in the nuclear industry in their education and/or professional practice.

Journal Articles

Thermodynamic study of the complexation of humic acid by calorimetry

Kimuro, Shingo; Kirishima, Akira*; Kitatsuji, Yoshihiro; Miyakawa, Kazuya; Akiyama, Daisuke*; Sato, Nobuaki*

Journal of Chemical Thermodynamics, 132, p.352 - 362, 2019/05

 Times Cited Count:6 Percentile:32.85(Thermodynamics)

A combination of potentiometry and calorimetry was used for the determination of the thermodynamic quantities of complexation of generic and groundwater humic acid (HA), which was isolated from deep groundwater at Horonobe, Hokkaido, Japan, with copper (II) ions and uranyl (VI) ions. The apparent complexation constant of Horonobe HA was independent of the pH, whereas that of generic HA was dependent on the pH. This observation indicates that the polyelectrolyte effect of Horonobe HA is negligible because of its small molecular size. In addition, the effect of the heterogeneity of Horonobe HA was not significant. Moreover, the complexation enthalpy of Horonobe HA was consistent with that of homogeneous poly(acrylic acid), which means the complexation of Horonobe HA was not affected by the functional group heterogeneity. Consequently, the characteristic complexation mechanism of Horonobe HA was revealed based on the determined thermodynamic quantities.

Journal Articles

Characterization and thermodynamic study of humic acid in deep groundwater at Horonobe, Hokkaido, Japan

Kimuro, Shingo*; Kirishima, Akira*; Nagao, Seiya*; Saito, Takumi*; Amano, Yuki; Miyakawa, Kazuya; Akiyama, Daisuke*; Sato, Nobuaki*

Journal of Nuclear Science and Technology, 55(5), p.503 - 515, 2018/05

 Times Cited Count:3 Percentile:46.85(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Determination of dissolved natural thorium and uranium in Horonobe and Mizunami Underground Research Laboratory groundwater and its thermodynamic analysis

Sasaki, Takayuki*; Kokami, Takayuki*; Kobayashi, Taishi*; Kirishima, Akira*; Murakami, Hiroaki; Amano, Yuki; Mizuno, Takashi; Iwatsuki, Teruki; Sasamoto, Hiroshi; Miyakawa, Kazuya

Journal of Nuclear Science and Technology, 54(3), p.373 - 381, 2017/03

Trace amounts of natural thorium and uranium in deep groundwater were investigated at two underground research laboratories situated at Horonobe and Mizunami, Japan. The groundwater was sampled from underground boreholes, and the colloid contribution was checked by in situ two size-fractionated ultrafiltration systems. A decrease in the concentration after in situ filtration suggested the presence of natural colloids and suspended matter that were carriers of a portion of the elements. The result of the Th and U concentrations in groundwater after 10 kDa filtration was analyzed thermodynamically using existing hydrogeological and geochemical data such as the mineral components in the groundwater at a given pH, ionic strength, concentration of co-existing ions, redox potential, and solid phase assumed. A crystalline solid phase made the solubility very low compared with that of the amorphous phase, and the solubility agreed well with the concentrations measured.

Journal Articles

Interaction of rare earth elements and components of the Horonobe deep groundwater

Kirishima, Akira*; Kuno, Atsushi*; Amamiya, Hiroki; Kubota, Takumi*; Kimuro, Shingo*; Amano, Yuki; Miyakawa, Kazuya; Iwatsuki, Teruki; Mizuno, Takashi; Sasaki, Takayuki*; et al.

Chemosphere, 168, p.798 - 806, 2017/02

 Times Cited Count:1 Percentile:93.63(Environmental Sciences)

For better understanding of the migration behavior of minor actinides (MA) in deep groundwater, the interaction of doped rare earth elements (REEs) and components in Horonobe deep groundwater was studied. Appx. 10 ppb of rare earth elements, i.e., Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm and Yb were doped to the sample groundwater collected from a packed sections in borehole drilled from 140 m depth experiment drift of Horonobe underground research laboratory (URL), Hokkaido, Japan. Then, that groundwater was sequentially filtrated by 0.2 micron pore filter, 10 kDa, 3 kDa and 1 kDa of nominal molecular weight limit (NMWL) ultrafilters by keeping inert condition. After that, the filtrate solutions were analyzed by ICP-MS to determine the concentrations of retained REEs at each filtration steps, while the used filters were analyzed by the neutron activation analysis (NAA) and TOF-SIMS element mapping to know the amount and chemical speciation of trapped fraction of the REEs on each filter. A remarkable relation between the retention ratios of REEs in the filtrate solutions and the ionic radius was observed, i.e., smaller rare earth element solves more in liquid phase under the Horonobe groundwater condition. NAA and TOF-SIMS analyses revealed that certain portions of REEs were trapped by 0.2 micron pore filters as rare earth phosphates which corresponded with the predicted predominant species by a chemical equilibrium calculation for the Horonobe groundwater condition, while small portions of colloidal REEs were trapped by 10 kDa and 3 kDa NMWL ultrafilters. The result suggested that phosphate anion plays an important role in the chemical behavior of REEs in saline (seawater based) groundwater, which could be referred for the prediction of migration behavior of trivalent actinide released from the repository of radioactive waste in far future.

Journal Articles

Recent activities in the field of nuclear waste management

Kitamura, Akira; Kirishima, Akira*

Journal of Nuclear Science and Technology, 52(3), p.448 - 450, 2015/03

 Times Cited Count:1 Percentile:11.57(Nuclear Science & Technology)

The Journal of Nuclear Science and Technology covers a variety of subjects in the field of nuclear waste management, which includes radioactive waste treatment, radioactive waste disposal and environment, decommissioning and dismantling. This summary introduces activities presented in recent years.

Journal Articles

Optical properties of tetravalent uranium complexes in non-aqueous media

Aoyagi, Noboru; Watanabe, Masayuki; Kirishima, Akira*; Sato, Nobuaki*; Kimura, Takaumi

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1095 - 1098, 2015/02

 Times Cited Count:4 Percentile:56.57(Chemistry, Analytical)

Journal Articles

The Present situation and future prospects of groundwater colloids studies on the performance assessment of geological disposal of radioactive wastes in Japan

Nagao, Seiya*; Niibori, Yuichi*; Tanaka, Tadao; Sasaki, Takayuki*; Saito, Takumi*; Kirishima, Akira*; Yoshikawa, Hideki; Iijima, Kazuki; Hama, Katsuhiro; Iwatsuki, Teruki; et al.

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 20(1), p.3 - 14, 2013/06

This paper shows a current status of groundwater colloids studies on the performance assessment of geological disposal of radioactive wastes in Japan, and summaries realistic approach of the colloids studies at a substantial research network for Japanese universities and institutes.

Journal Articles

Electronic absorption spectra of palladium(II) in concentrated nitric acid solutions

Fujii, Toshiyuki*; Egusa, Soichiro*; Uehara, Akihiro*; Kirishima, Akira*; Yamagishi, Isao; Morita, Yasuji; Yamana, Hajimu*

Journal of Radioanalytical and Nuclear Chemistry, 290(2), p.475 - 478, 2011/11

 Times Cited Count:15 Percentile:22.54(Chemistry, Analytical)

Palladium complexation in concentrated nitric acid solutions was studied by UV/Vis absorption spectrophotometry. The ionic strength of the solutions was fixed to $$I$$ = 1, 3, or 5 M by mixing of HNO$$_{3}$$ and HClO$$_{4}$$. The major palladium species were found to be Pd$$^{2+}$$, PdNO$$_{3}$$$$^{+}$$, and Pd(NO$$_{3}$$)$$_{2}$$. The formation constant of PdNO$$_{3}$$$$^{+}$$ was determined to be $$beta$$$$_{1}$$ = 1.32 ($$I$$ = 1 M), 1.49 ($$I$$ = 3 M), or 1.47 ($$I$$ = 5 M), while that of Pd(NO$$_{3}$$)$$_{2}$$ to be $$beta$$$$_{2}$$ = 0.45 ($$I$$ = 3 M) or 0.14 ($$I$$ = 5 M).

Journal Articles

Fundamental study of the sulfide reprocessing process for oxide fuel, 1; Study on the Pu, MA and FP tracer-doped U$$_{3}$$O$$_{8}$$

Kirishima, Akira*; Mitsugashira, Toshiaki*; Onishi, Takashi; Sato, Nobuaki*

Journal of Nuclear Science and Technology, 48(6), p.958 - 966, 2011/06

 Times Cited Count:3 Percentile:70.32(Nuclear Science & Technology)

A novel reprocessing process based on the selective sulfurization of fission products (FP) has been proposed, where FP and minor actinides (MA) are first sulfurized by CS$$_{2}$$ gas, and then, dissolved by a dilute nitric acid solution. Consequently, the fuel elements are recovered as UO$$_{2}$$ and PuO$$_{2}$$. As a basic research of this new concept, the sulfurization and dissolution behaviors of U, Pu, Np, Am, Eu, Cs and Sr were investigated in this paper using $$^{236}$$Pu, $$^{237}$$Np, $$^{241}$$Am, $$^{152}$$Eu, $$^{137}$$Cs and $$^{85}$$Sr doped U$$_{3}$$O$$_{8}$$ sample by $$gamma$$ ray and $$alpha$$ spectrometries. The dependence of the dissolution ratio of each element on the sulfurization temperature was studied and reasonably explained by combining the information of the sulfide phase analysis and the chemical thermodynamics of the dissolution reaction. The sulfurization temperature ranging from 350 to 450 $$^{circ}$$C seems to be promising for the separation of FP and MA from U and Pu.

JAEA Reports

JAEA thermodynamic database for performance assessment of geological disposal of high-level and TRU wastes; Selection of thermodynamic data of molybdenum

Kitamura, Akira; Kirishima, Akira*; Saito, Takumi*; Shibutani, Sanae*; Tochiyama, Osamu*

JAEA-Review 2010-010, 75 Pages, 2010/06

JAEA-Review-2010-010.pdf:1.27MB

Within the scope of the JAEA thermodynamic database project for performance assessment of geological disposal of high-level radioactive and TRU wastes, the selection of the thermodynamic data on the inorganic compounds and complexes of molybdenum were carried out. We focused to select thermodynamic data of aquous species and compounds which could form under repository conditions for the disposal of radioactive wastes, i.e. relatively low concentration of molybdenum and from near neutral through alkaline conditions. Selection of thermodynamic data was based on the guidelines by the Nuclear Energy Agency in the Organisation for Economic Co-operation and Development (OECD/NEA). Extensive literature survey was performed and all the obtained articles have been carefully reviewed to select the thermodynamic data for molybdenum. Thermodynamic data at 25 $$^{circ}$$C and zero ionic strength were determined from accepted thermodynamic data which were considered to be reliable. We especially paid attention to select formation constant of molybdate ion with hydrogen ion.

JAEA Reports

JAEA thermodynamic database for performance assessment of geological disposal of high-level and TRU wastes; Selection of thermodynamic data on cobalt and nickel

Kitamura, Akira; Kirishima, Akira*; Saito, Takumi*; Shibutani, Sanae*; Tochiyama, Osamu*; Yui, Mikazu

JAEA-Research 2009-037, 91 Pages, 2009/11

JAEA-Research-2009-037.pdf:4.04MB

Within the scope of the JAEA thermodynamic database project for performance assessment of geological disposal of high-level and TRU radioactive wastes, the selection of the thermodynamic data on the inorganic compounds and complexes of cobalt and nickel have been carried out. For cobalt, extensive literature survey has been performed and all the obtained literatures have been carefully reviewed to select the thermodynamic data. Selection of thermodynamic data of nickel has been based on a thermodynamic database published by the OECD/NEA, which has been carefully reviewed by the authors, and then thermodynamic data have been selected after surveying latest literatures. Based on the similarity of chemical properties between cobalt and nickel, complementary thermodynamic data of nickel and cobalt species expected under the geological disposal condition have been selected to complete the thermodynamic data set for the performance assessment of geological disposal of radioactive wastes.

Journal Articles

Complexation and back extraction of various metals by water-soluble diglycolamide

Sasaki, Yuji; Sugo, Yumi; Kitatsuji, Yoshihiro; Kirishima, Akira*; Kimura, Takaumi; Choppin, G. R.*

Analytical Sciences, 23(6), p.727 - 731, 2007/06

 Times Cited Count:51 Percentile:15.25(Chemistry, Analytical)

Water-soluble ligands, tetramethyl-diglycolamide (TMDGA), tetraethyl-diglycolamide (TEDGA), tetrapropyl-diglycolamide (TPDGA) and dipropyl-diglycolamic acid (DPDGAc) were prepared and their abilities to complex with the metal cations were investigated. These results indicate that the DGA series and DPDGAc have stronger complexing ability with Am(III) and Pu(IV) than comparable carboxylic and aminopolycarboxylic acids. Among these ligands, the trend of the strength of their complexing ability is TPDGA $$sim$$ TEDGA $$>$$ TMDGA $$sim$$ DPDGAc. TPDGA has significant loss to the extraction solvent due to its high hydrophobicity. It is evident from the present work that TEDGA is the best stripping reagent not only for An(III), (IV) but also Ca(II), Sc(III), Y(III), Zr(IV), La(III), Hf(IV), and Bi(III).

Journal Articles

Sulfurization of rare-earth oxides in simulated spent fuel

Shinohara, Genki*; Sato, Nobuaki*; Kirishima, Akira*; Tochiyama, Osamu*; Sato, Soichi

Proceedings of 16th Iketani Conference: Masuko Symposium, p.153 - 160, 2006/11

For the recovery of uranium from spent nuclear fuel, the sulfide reprocessing process has been proposed. The process consists of voloxidation and sulfurization steps followed by either magnetic separation or selective leaching steps. In this process, selective sulfurization of the rare-earth elements is applied, while the uranium oxide remains unreacted. The sulfurization of rare-earth oxides R$$_{2}$$O$$_{3}$$ (R=Nd, Eu) was examined using CS$$_{2}$$, and found that they formed oxysulfide and sulfides even at temperatures lower than 500$$^{circ}$$C. From the results of the sulfurization of R$$_{2}$$O$$_{3}$$ in the simulated spent fuel, it was found that R$$_{2}$$O$$_{3}$$ for Nd and Eu were selectively sulfurized by CS$$_{2}$$ at 500$$^{circ}$$C forming Nd$$_{2}$$S$$_{3}$$ and EuS, respectively, while uranium remained as UO$$_{2}$$. Effects of sulfurizing temperature and time were also investigated and compared with the results of thermodynamic consideration.

Journal Articles

Association of europium(III), americium(III), and curium(III) with cellulose, chitin, and chitosan

Ozaki, Takuo; Kimura, Takaumi; Onuki, Toshihiko; Kirishima, Akira*; Yoshida, Takahiro*; Isobe, Hiroshi*; Francis, A. J.

Environmental Toxicology and Chemistry, 25(8), p.2051 - 2058, 2006/08

 Times Cited Count:5 Percentile:85.26(Environmental Sciences)

no abstracts in English

Journal Articles

Recent progress on solution chemistry of actinides studied by time-resolved laser-induced fluorescence spectroscopy

Kimura, Takaumi; Kirishima, Akira*; Arisaka, Makoto

Kidorui, (47), p.43 - 56, 2005/11

no abstracts in English

Journal Articles

Study on stabilization effect of neutral soft donor on trivalent lanthanide and actinide dicarboxylate complexes by time-resolved laser-induced fluorescence spectroscopy

Sasaki, Takayuki*; Kubo, Shintaro*; Kobayashi, Taishi*; Kirishima, Akira*; Kimura, Takaumi; Kubota, Takumi*; Takagi, Ikuji*; Moriyama, Hirotake*

Journal of Nuclear and Radiochemical Sciences, 6(1), p.51 - 54, 2005/07

no abstracts in English

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:19 Percentile:22.27(Chemistry, Inorganic & Nuclear)

no abstracts in English

72 (Records 1-20 displayed on this page)