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Journal Articles

Optimization of chemical composition in the iron phosphate glass as the matrix of high level waste generated from pyroprocessing

Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07

For the research and development of the nuclear waste disposal concept suitable to the pyrochemical processing system and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from electro-refining process. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of the glass composition were carried out and the effect of additional other transition metal oxides was found out in this study.

Journal Articles

Simulation of VDE under intervention of vertical stability control and vertical electromagnetic force on the ITER vacuum vessel

Miyamoto, Seiji; Sugihara, Masayoshi*; Shinya, Kichiro*; Nakamura, Yukiharu*; Toshimitsu, Shinichi*; Lukash, V. E.*; Khayrutdinov, R. R.*; Sugie, Tatsuo; Kusama, Yoshinori; Yoshino, Ryuji*

Fusion Engineering and Design, 87(11), p.1816 - 1827, 2012/11

 Times Cited Count:13 Percentile:72.35(Nuclear Science & Technology)

Journal Articles

Chemical durability of iron-phosphate glass as the high level waste from pyrochemical reprocessing

Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*

Procedia Chemistry, 7, p.764 - 771, 2012/00

 Times Cited Count:10 Percentile:95.16

As a part of the research and development for the nuclear waste disposal concept suitable to the advanced fuel cycle systems and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from pyrochemical reprocessing. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of glass composition were carried out and the effect of additional other transition metal oxides was found out in this study.

Journal Articles

Effect of sodium nitrate on the diffusion of Cl$$^{-}$$ and I$$^{-}$$ in compacted bentonite

Ishidera, Takamitsu; Miyamoto, Shinya*; Sato, Haruo

Journal of Nuclear Science and Technology, 45(7), p.610 - 616, 2008/07

 Times Cited Count:11 Percentile:61.18(Nuclear Science & Technology)

For safety assessment of TRU waste disposal, the effective diffusion coefficients ($$D$$$$_{e}$$) for CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$ and I$$^{-}$$ ions in compacted bentonite (Kunigel V1) were determined as a function of NaNO$$_{3}$$ concentrations from 0.01 to 5 mol/dm$$^{3}$$. The $$D$$$$_{e}$$ values increased from 10$$^{-12}$$ to 10$$^{-11}$$ m$$^{2}$$/s with increasing NaNO$$_{3}$$ concentration. The rock capacity factor $$alpha$$, indicative of the effective porosity, were also increased with increasing NaNO$$_{3}$$ concentration. The maximum $$alpha$$ values of 0.21 for Cl$$^{-}$$ ion and of 0.25 for I$$^{-}$$ ion at 5 mol/dm$$^{3}$$ NaNO$$_{3}$$ concentration were lower than the net porosity of compacted bentonite (0.40). Therefore, the increases in the $$D$$$$_{e}$$ values were interpreted by the decrease of anion exclusion effect. The $$D$$$$_{e}$$ values for Cl$$^{-}$$ and I$$^{-}$$ ions normalized by the diffusivities for diffusants in the bulk water were found to increase in proportion to the $$alpha$$ values on the log-log diagram. The maximum $$alpha$$ value for CO$$_{3}$$$$^{2-}$$ ion was higher than the net porosity. The high concentration of CO$$_{3}$$$$^{2-}$$ ion was also found in the concentration profile in compacted bentonite. This retention of CO$$_{3}$$$$^{2-}$$ ion was possibly accounted for by isotopic exchange of $$^{14}$$C with inactive carbon of calcite in Kunigel V1.

JAEA Reports

Dependence of Concentration of Ammonium Chloride on Solubility of Nickel

Miyamoto, Shinya*; Sato, Mitsuyoshi*; Mihara, Morihiro

JNC TN8400 2005-028, 21 Pages, 2005/09

JNC-TN8400-2005-028.pdf:25.6MB

It is planning that radioactive wastes of high alpha concentration generated from reprocessing plant of spent nuclear fuel will be disposed in deep underground repository in Japan. Using the nitrate acid in the reprocessing process, some of radioactive wastes include lots of nitrate salts. The solubility of nitrate salts is very high and they might easily dissolve in groundwater in the repository. In the repository, many steels also will be disposed and nitrate will be reduced to ammonium ion by the interaction of steel. In this study, first the solubility experiments of nickel were performed to evaluate the effect of ammonium ion on solubility. Next the geochemical modeling also was carried out to explain results of solubility experiments using published thermodynamic data of nickel and ammonia. Under conditions of more than 1mol/dm$$^{3}$$ of ammonium chloride, the enhancement of solubility of nickel was observed. It showed 2 or 3 orders magnitude of higher than those of less than 1mol/dm$$^{3}$$ of ammonium chloride. These data were explained by geochemical modeling using data of ammine complex.

Journal Articles

The Effect of Silica Sand Content on Diffusion of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$ and I$$^{-}$$ ions in Compacted Bentonite

Ishidera, Takamitsu; Miyamoto, Shinya*; Sato, Haruo

JAERI-Conf 2005-007, p.264 - 269, 2005/05

For safety assessment of TRU waste disposal, the effective diffusion coefficients (De) for CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$ and I$$^{-}$$ ions in compacted bentonite (Kunigel V1) were determined as a function of silica sand contents under hyper alkaline condition. The obtained De values for three diffusants were on the order of 10$$^{-13}$$ - 10$$^{-11}$$ m$$^{2}$$/s and increased with increasing silica sand content. The effective porosity for diffusion of Cl$$^{-}$$ and I$$^{-}$$ ions, estimated from the rock capacity factor values, were also increased with increasing silica sand content. This close relationship indicated that the increases in the De values were due to the increase in effective porosity with increasing silica sand content. In the case of CO$$_{3}$$$$^{2-}$$ ion, the rock capacity factor values were higher than those for Cl$$^{-}$$ and I$$^{-}$$ ions. The Da values for CO$$_{3}$$$$^{2-}$$ ion were approximately one order of magnitude lower than those for Cl$$^{-}$$ and I$$^{-}$$ ions. The differences in these behaviors suggested a possibility of isotopic exchange of $$^{14}$$C with the carbon of calcite contained in Kunigel V1.

JAEA Reports

The Effect of Silica Sand Content and NaNO$$_{3}$$Concentration on Diffusions of C, Cl and I in Compacted Bentonite

Ishidera, Takamitsu; Miyamoto, Shinya*; Sato, Haruo

JNC TN8400 2004-001, 21 Pages, 2004/05

JNC-TN8400-2004-001.pdf:0.43MB

For safety assessment of geological disposal of TRU waste, it is necessary to obtain the diffusivities of C-14, Cl-36 and I-129 and to estimate the effects of the dissolution of NaNO$$_{3}$$and high pH groundwater condition caused by dissolution of cementitious materials. Therefore, the effective diffusion coefficients (De) and the apparent diffusion coefficients (Da) of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$and I$$^{-}$$in compacted bentonite were obtained as a function of silica sand content and NaNO$$_{3}$$concentration under high pH condition by Through-diffusion method. Furthermore, the diffusion mechanisms of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$and I$$^{-}$$were discussed.The obtained De values of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$and I$$^{-}$$were in a range of 10$$^{-13}$$to 10$$^{-10}$$m$$^{2}$$/s order and Da values in a range of 10$$^{-12}$$to 10$$^{-11}$$m$$^{2}$$/s order (CO$$_{3}$$$$^{2-}$$) and 10$$^{-10}$$m$$^{2}$$/s order (Cl$$^{-}$$and I$$^{-).}$$The De and Da values of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$and I$$^{-}$$increased with increasing silica sand content. The changes of De and Da values appeared to be estimated by smectite partial density. The De values of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$and I$$^{-}$$increased with increasing NaNO$$_{3}$$concentration. The increases were interpreted by the decrease of anion exclusion effect. Furthermore, it seems that the pathways of Cl$$^{-}$$and I$$^{-}$$were limited to the interstitial pore space. The CO$$_{3}$$$$^{2-}$$ions were probably retained in the Kunigel V1 as the precipitation of calcite.

Journal Articles

The Effect of Silica Sand Content and NaNO$$_{3}$$on Diffusion of CO$$_{3}$$$$^{2-}$$, Cl$$^{-}$$ and I$$^{-}$$ in Compacted Bentonite

Ishidera, Takamitsu; Shinya, Miyamoto,; Sato, Haruo

Saikuru Kiko Giho, (25), p.85 - 93, 2004/00

The concept of air transport of A Type package containing nuclear fuel materials according to the nuclear disaster countermeasures law, and the experience of a transportation of plutonium solution from France are shown.

Oral presentation

Technical development on immobilization/solidification of waste salt arising from pyroprocessing, 1; Fundamental study on applicability of use of iron phosphate glass as waste form

Amamoto, Ippei; Fukushima, Mineo; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*; Utsunomiya, Kazuhiro*; Yano, Tetsuji*

no journal, , 

no abstracts in English

Oral presentation

Technical development on immobilization/solidification of waste salt arising from pyroprocessing, 2; Fundamental study on physical properties of iron phosphate glass as waste form

Amamoto, Ippei; Fukushima, Mineo; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*; Utsunomiya, Kazuhiro*; Yano, Tetsuji*

no journal, , 

no abstracts in English

Oral presentation

DINA analysis on effect of vertical position control on vertical force during VDE

Miyamoto, Seiji; Sugihara, Masayoshi*; Shinya, Kichiro*; Nakamura, Yukiharu*; Toshimitsu, Shinichi; Sugie, Tatsuo; Kusama, Yoshinori; Yoshino, Ryuji

no journal, , 

When Plasma Control System (PCS) generates wrong signal to the PF coils and in-vessel vertical stabilization (VS) coils, it could be happen that the vertical force somewhat larger than presently specified could be generated. Example is that though plasma moves downward, but PCS erroneously recognizes it is moving upward. Then PF coils start to generate the field pattern that tends to push plasma further downward and resultantly the force could be larger than the present specification, in which it is evaluated with the assumption that control system (PF coils) does nothing (i.e., short-circuited.) In fact, in the existing machines, this is the worst case. The DINA code is used to analyze the vertical force, which has been updated to incorporate the recent design change of the vacuum vessel and in-vessel VS coils. In the presentation, analysis of VS effect on the vertical force is discussed using the updated DINA code.

Oral presentation

Surface structures of iron-phosphate glasses with high chemical durability

Yano, Tetsuji*; Akagi, Naoto*; Shibata, Shuichi*; Okita, Takeshi*; Matsuyama, Kanae*; Miyamoto, Shinya*; Amamoto, Ippei; Kofuji, Hirohide

no journal, , 

Surface structures of iron phosphate glasses (IPG) are investigated in order to know the origin of the high chemical durability using X-ray photoelectron spectroscopy. In this study, several IPG samples in which a part of iron oxide are replaced by other transition metal oxides are prepared and subjected to the chemical durability test. Surface structures are investigated before and after the durability test and the information on the structural changes are obtained.

Oral presentation

Chemical durability of iron-phosphate glass as the high level waste from pyrochemical reprocessing

Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Okita, Takeshi*; Miyamoto, Shinya*

no journal, , 

As a part of the research and development for the nuclear waste disposal concept suitable to the advanced fuel cycle systems and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from pyrochemical reprocessing. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of glass composition were carried out in this study.

Oral presentation

Development on immobilization/solidification of waste salt arising from pyroprocessing, 4; Evaluation of physical properties and chemical durability of iron phosphate glass

Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*

no journal, , 

no abstracts in English

Oral presentation

Surface alternation of Cr$$_{2}$$O$$_{3}$$-CoO-Al$$_{2}$$O$$_{3}$$-doped iron-phosphate glasses containing fission products during immersion in water and heating in vacuum

Yano, Tetsuji*; Tateno, Hayato*; Kishi, Tetsuo*; Okita, Takeshi*; Matsuyama, Kanae*; Miyamoto, Shinya*; Kofuji, Hirohide; Myochin, Munetaka

no journal, , 

15 (Records 1-15 displayed on this page)
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