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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

Structural change of borosilicate glass by boron isotope composition

Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Uehara, Akihiro*; Fujii, Toshiyuki*; Sekimoto, Shun*

KURNS Progress Report 2019, P. 257, 2020/08

To understand the influence of glass structural change by neutron irradiation and boron isotope composition, glass samples were made from enrichment boric acid reagents and neutron irradiation of those samples was carried out in Pn-2 of KUR. The structural change of glass sample after the irradiation will be estimated in 2020FY. Before neutron irradiation test of glass samples, the Si-O bridging structure difference by boron isotope composition compared by using a Raman spectrometry.

Journal Articles

Investigation of chemical state of simulated waste glasses by using XAFS measurement

Nagai, Takayuki; Shimoyama, Iwao; Okamoto, Yoshihiro; Akiyama, Daisuke*; Arima, Tatsumi*

Photon Factory Activity Report 2019 (Internet), 3 Pages, 2020/00

no abstracts in English

Journal Articles

Structural change of borosilicate glass by neutron irradiation

Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*; Uehara, Akihiro*; Fujii, Toshiyuki*; Sekimoto, Shun*

KURNS Progress Report 2018, P. 105, 2019/08

To understand this structural change of a borosilicate glass by a neutron irradiation in detail, the irradiation test was carried out in KUR in 2017FY. The glass structure was estimated by using Raman spectrometry in 2018FY. Comparing with the Raman spectra of glass samples before and after irradiation, it could be observed the change of peak height of Si-O bridging structure by the irradiation.

Journal Articles

Investigation of chemical state of uranium included in simulated waste glass

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

"Busshitsu, Debaisu Ryoiki Kyodo Kenkyu Kyoten" Oyobi "Hito, Kankyo To Busshitsu O Tsunagu Inobeshion Soshutsu Danamikku, Araiansu" Kenkyu Seika, Katsudo Hokokusho (Heisei-30-Nendo) (CD-ROM), P. 20181080_1, 2019/06

no abstracts in English

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:5 Percentile:27.25(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

Evaluation of uranium chemical state in borosilicate glasses by using XAFS measurement

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

Photon Factory Activity Report 2018 (Internet), 2 Pages, 2019/00

no abstracts in English

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:40.19(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Investigation of chemical state of uranium included in glass

Nagai, Takayuki; Akiyama, Daisuke*; Sato, Nobuaki*

Busshitsu, Debaisu Ryoiki Kyodo Kenkyu Kyoten Kenkyu Seika Hokokusho (Heisei-29-Nendo) (CD-ROM), 1 Pages, 2018/04

no abstracts in English

Journal Articles

Evaluation of uranium chemical state in borosilicate glasses by using XAFS measurement

Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*

Photon Factory Activity Report 2017, 2 Pages, 2018/00

no abstracts in English

Journal Articles

Chemical behavior of platinum group compounds in the vitrification process condition

Nagai, Takayuki; Akiyama, Daisuke*; Sato, Nobuaki*; Sasage, Kenichi

Busshitsu, Debaisu Ryoiki Kyodo Kenkyu Kyoten Kenkyu Seika Hokokusho (Heisei-28-Nendo) (CD-ROM), 1 Pages, 2017/03

no abstracts in English

Journal Articles

Hexafluoro complex of rutherfordium in mixed HF/HNO$$_{3}$$ solutions

Toyoshima, Atsushi; Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Akiyama, Kazuhiko*; Goto, Shinichi*; Ishii, Yasuo; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; et al.

Radiochimica Acta, 96(3), p.125 - 134, 2008/03

 Times Cited Count:26 Percentile:12.89(Chemistry, Inorganic & Nuclear)

Formation of an anionic fluoride-complex of element 104, rutherfordium (Rf) produced in the $$^{248}$$Cm($$^{18}$$O,5n)$$^{261}$$Rf reaction was studied by an anion-exchange method based on an atom-at-a-time scale. It was found that the hexafluoro complex of Rf, [RfF$$_{6}$$]$$^{2-}$$, was formed in the studied fluoride ion concentrations of 0.0005 - 0.013 M. Formation of [RfF$$_{6}$$]$$^{2-}$$ was significantly different from that of the homologues Zr and Hf, [ZrF$$_{6}$$]$$^{2-}$$ and [HfF$$_{6}$$]$$^{2-}$$; the evaluated formation constant of [RfF$$_{6}$$]$$^{2-}$$ is at least one-order of magnitude smaller than those of [ZrF$$_{6}$$]$$^{2-}$$ and [HfF$$_{6}$$]$$^{2-}$$.

Journal Articles

Chemical studies on rutherfordium (Rf) at JAERI

Nagame, Yuichiro; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Akiyama, Kazuhiko; Ishii, Yasuo; Sato, Tetsuya; Hirata, Masaru; Nishinaka, Ichiro; Ichikawa, Shinichi; et al.

Radiochimica Acta, 93(9-10), p.519 - 526, 2005/00

 Times Cited Count:28 Percentile:11.79(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Elution curve of Rutherfordium (Rf) in anion-exchange chromatography with hydrofluoric acid solution

Toyoshima, Atsushi; Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Akiyama, Kazuhiko; Nishinaka, Ichiro; Nagame, Yuichiro; Saika, Daisuke*; Matsuo, Keishi*; Sato, Wataru*; et al.

Journal of Nuclear and Radiochemical Sciences, 5(2), p.45 - 48, 2004/12

no abstracts in English

Oral presentation

Protonation mechanism of humic acid isolated from deep groundwater in Horonobe

Kimuro, Shingo*; Kirishima, Akira*; Akiyama, Daisuke*; Sato, Nobuaki*; Mizuno, Takashi; Amano, Yuki; Nanjo, Isao*

no journal, , 

no abstracts in English

Oral presentation

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

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

no journal, , 

In this study, size exclusion chromatography (SEC), flow-field flow fractionation (Fl-FFF) and calorimetry were applied to the humic acid isolated from the groundwater collected at 350m below the ground level at the Horonobe Underground Research Laboratory, JAEA. First, the characteristic molecular weight distribution of Horonobe humic acids were observed from the SEC analysis. Second, the small hydrodynamic diameter of Horonobe humic acids were observed by the Fl-FFF. Finally, the protonation enthalpies of Horonobe humic acids were determined by the combination of potentiometry and calorimetry. The values of protonation enthalpy of Horonobe humic acids were close to simple organic acids (i.e., benzoic acid and phenol). It was suggested that Horonobe humic acids have lower molecular weight than IHSS surface soil humic acids (Elliot Soil and Waskish Peat) and the simple protonation mechanism, which is not affected by the heterogeneity.

Oral presentation

Characterization and determination of thermodynamic quantities of humic acid dissolved in deep groundwater at Horonobe, Hokkaido, Japan

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

no journal, , 

no abstracts in English

Oral presentation

Pa solution chemistry study for uranium waste management, 1; Purification of Pa-231 and UV-Vis-NIR spectroscopy

Kirishima, Akira*; Watanabe, Masayuki; Kitatsuji, Yoshihiro; Segawa, Yukari; Aoyagi, Noboru; Akiyama, Daisuke*; Sato, Nobuaki*

no journal, , 

$$^{231}$$Pa is one of the most important nuclide in the safety evaluation due to its long life time, 32760 years. In the case of shallow geological disposal of Uranium waste, $$^{231}$$Pa which is a daughter of $$^{235}$$Uranium would become dominant nuclei for public exposure of radioactivity after about 1000 year from the disposal. We start to understand some basic properties of Pa such as hydrolysis, stability constants with simple ligands and spectroscopic parameters because little is known about essential properties of Pa. In this presentation, we will report some results on the purification of Pa with solvent extraction, UV-VIS-NIR spectroscopy of Pa and stability constant with fluoride.

Oral presentation

Redox behavior of Ru in NaNO$$_{3}$$ melt

Nagai, Takayuki; Okamoto, Yoshihiro; Inose, Takehiko*; Akiyama, Daisuke*; Sato, Nobuaki*

no journal, , 

A supplied high level liquid waste into the glass melter is formed to the mixed nitrate salt after the dehydration. In this study, NaNO$$_{3}$$ which is a main ingredient in the waste was selected by the solvent, and NaNO$$_{3}$$ sample including Ru was prepared, and the redox behavior of Ru in NaNO$$_{3}$$ melt was measured by the Cyclic Voltammetry. And valence of Ru included in solidified salt was estimated by the synchrotron XAFS measurement.

Oral presentation

Characterization and determination of thermodynamic quantities of humic acid dissolved in deep groundwater at Horonobe, Hokkaido, Japan, 2

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

no journal, , 

no abstracts in English

39 (Records 1-20 displayed on this page)