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Nagai, Takayuki; Okamoto, Yoshihiro; Shiwaku, Hideaki; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*; Hirono, Kazuya*; Homma, Masanobu*; Kobayashi, Hiromi*; Takahashi, Tomoe*; et al.
JAEA-Research 2018-007, 87 Pages, 2018/11
To select the chemical composition of a glass frit which can increase the waste content, the simulated waste glass samples prepared from a borosilicate glass frit including vanadium (V) were investigated by using Laser Ablation (LA) ICP-AES analysis, Raman spectrometry, and synchrotron XAFS measurement in this study on foundation business of the Agency for Natural Resources and Energy.
Nagai, Takayuki; Okamoto, Yoshihiro; Kano, Shigeru; Nishizawa, Daiji; Seki, Katsumi*; Homma, Masanobu*; Kobayashi, Hiromi*; Ayame, Yasuo
no journal, ,
no abstracts in English
Nagai, Takayuki; Nishizawa, Daiji*; Watanabe, So; Okamoto, Yoshihiro; Seki, Katsumi*; Homma, Masanobu*; Ayame, Yasuo
no journal, ,
no abstracts in English
Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Seki, Katsumi*; Kobayashi, Hiromi*; Homma, Masanobu*; Hatakeyama, Kiyoshi*
no journal, ,
It is expected by bubbling operation of molten glass that glass composition becomes uniform. Air or Ar gas was purged into the molten simulated waste glass, and the drained glass was investigated by Raman spectrophotometry and synchrotron XAFS measurement. As a result, the Si-O bridging structure with a small number of non-bridging oxygen increases by Ar gas purging into the molten glass and also valence of Ce included in the simulated waste glass reduces.
Okamoto, Yoshihiro; Kobayashi, Hidekazu; Nagai, Takayuki; Kobayashi, Hiromi*; Homma, Masanobu*; Hirono, Kazuya*; Hatakeyama, Kiyoshi*; Shiwaku, Hideaki
no journal, ,
Bottom drain test of iron phosphate glass containing simulated high level liquid waste (HLLW) components were performed using small size melting furnace. The glass samples collected from the furnace was analyzed by synchrotron radiation based XAFS technique. The 20wt% HLLW components was mixed with the iron phosphate glass having a composition of 35mol%FeO-PO was used as base glass. They were melted and kept at 1150C in the furnace and the melts were drained out to 6 alumina crucibles. As the results of XAFS analysis for the solidified samples, oxidation state of cerium was trivalent and that of molybdenum was pentavalent. Their oxidation states are more reducing in comparison with borosilicate glass samples. The imaging XAFS analysis showed that small RuO particles distributed in the sample were not aggregated in the glass sample. These results were compatible with our previous work in which the glass samples were prepared only in crucibles.
Nagai, Takayuki; Kaneko, Koji; Motokawa, Ryuhei; Okamoto, Yoshihiro; Haga, Yoshinori; Kobayashi, Hiromi*; Homma, Masanobu*; Hatakeyama, Kiyoshi*; Hirono, Kazuya*
no journal, ,
no abstracts in English
Okamoto, Yoshihiro; Nagai, Takayuki; Shiwaku, Hideaki; Seki, Katsumi*; Kobayashi, Hiromi*; Homma, Masanobu*; Hatakeyama, Kiyoshi*
no journal, ,
The chemical state of simulated radioactive waste glass prepared by bottom drain tests was investigated by XAFS and imaging XAFS analyses. Gas bubbling operation at melting was added in the test. The XAFS measurements of Cr, Mn, Fe and Ce were performed to evaluate redox (reduction and oxidation) state in the simulated glass. Behavior of platinum group elements in the simulated glass was observed from the imaging XAFS analysis. The XAFS analysis suggested redox state of the glass changed depending on the waste content and the gas bubbling. The imaging XAFS analysis showed that aggregation of platinum group element was reduced by the gas bubbling.
Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Seki, Katsumi*; Kobayashi, Hiromi*; Homma, Masanobu*; Hatakeyama, Kiyoshi*
no journal, ,
no abstracts in English
Okamoto, Yoshihiro; Nagai, Takayuki; Kobayashi, Hidekazu; Shiwaku, Hideaki; Seki, Katsumi*; Kobayashi, Hiromi*; Homma, Masanobu*; Hatakeyama, Kiyoshi*
no journal, ,
Research work on vitrification technique with higher loading capacity of high-level liquid waste in the glass is important in order to reduce total amount of waste generated. In the present work, synchrotron radiation based XAFS analysis was performed for the glass samples obtained from bottom drain tests with several conditions such as different loading capacities and gas bubbling. As the results of XAFS analysis, it can be seen that distribution of platinum group metal (PGM) in the glass is scattered and oxidation state of some elements such as chromium changed into reduction state. On the other hand, oxidation state of some elements like iron and zinc did not changed by the bubbling. These results suggest behavior of each element in the borosilicate glass can be evaluated from information on its spacial distribution and local coordination.
Okamoto, Yoshihiro; Nagai, Takayuki; Kobayashi, Hiromi*; Homma, Masanobu*; Hatakeyama, Kiyoshi*; Hirono, Kazuya*; Shiwaku, Hideaki
no journal, ,
The chemical state of some elements contained in the simulated waste glass samples prepared by bottom drain test using a small furnace was investigated by synchrotron XAFS analysis. The effect of gas bubbling in the molten state and the effect of waste loading rate variation (2030wt%) were evaluated from the results of XAFS analysis of each element. As a result of XAFS analysis, the tendency to become oxidative due to high waste loading rate and to become reductive by bubbling with reducing gas was recognized. On the other hand, it was found that they are classified into elements that are affected and those that are not affected. The bubbling operation has been tested in an actual plant, and these results are expected to provide meaningful information for the operation.
Nagai, Takayuki; Okamoto, Yoshihiro; Kaneko, Koji; Motokawa, Ryuhei; Kobayashi, Hiromi*; Homma, Masanobu*; Hirono, Kazuya*
no journal, ,
To understand the structural property of borosilicate glass frit for vitrification of radioactive wastes, we prepared the glass frit samples which coordinated alkaline component and BO amount and measured the Si-O bridge structure of those samples by using Raman spectrometer. Moreover, we made the simulated waste glass samples which added non-radioactive nitrate solution to those frit and observed a change of Raman spectra by glass composition.