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Journal Articles

Research on vitrification technology to immobilize radioactive sludge generated from Fukushima Daiichi Power Plant; Enhanced glass medium

Amamoto, Ippei; Kobayashi, Hidekazu; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*; Fukayama, Daigen*; Nagano, Yuichi*; Jantzen, T.*; Hack, K.*

Journal of Nuclear Science and Technology, 53(10), p.1467 - 1475, 2016/10

 Times Cited Count:1 Percentile:14.27(Nuclear Science & Technology)

The iron phosphate glass (IPG) medium is known to be a high-efficiency glass medium, therefore we try to evaluate its applicability to immobilize sludge bearing radioactive nuclides arising from treatment of contaminated water at the stricken Fukushima Daiichi Nuclear Power Plant. For this study, many physical and chemical properties of target materials are necessary to evaluate the behaviours of IPG medium and its waste forms. Inevitably, it will entail the need for many and varied types of experiments to be carried out under high temperature. It is therefore rational to apply appropriate theoretical analysis first so as to reduce the number of experimental run. For this reason, some necessary thermodynamic values for theoretical analysis were estimated by CALPHAD approach followed by making up the calculated phase diagrams. By comparison with experimental results, they were found to be reliable for evaluating the behaviours of IPG medium and its waste forms.

JAEA Reports

Light ion microbeam analysis / processing system and its improvement

Koka, Masashi; Ishii, Yasuyuki; Yamada, Naoto; Okubo, Takeru; Kada, Wataru*; Kitamura, Akane; Iwata, Yoshihiro*; Kamiya, Tomihiro; Sato, Takahiro

JAEA-Technology 2016-006, 41 Pages, 2016/03

JAEA-Technology-2016-006.pdf:14.03MB

A MeV-class light ion microbeam system has been developed for micro-analysis and micro-fabrication with high spatial resolution at 3-MV single-ended accelerator in Takasaki Ion Accelerators for Advanced Radiation Application of Takasaki Advanced Radiation Research Institute, Sector of Nuclear Science Research, Japan Atomic Energy Agency. This report describes the technical improvements for the main apparatus (the accelerator, beam-transport lines, and microbeam system), and auxiliary equipments/ parts for ion beam applications such as Particle Induced X-ray/Gamma-ray Emission (PIXE/PIGE) analysis, 3-D element distribution analysis using PIXE-Computed Tomography(CT), Ion Beam-Induced Luminescence (IBIL) analysis, and Proton Beam Writing with the microbeam scanning, with functional outline of these apparatus and equipments/parts.

Journal Articles

Study of annealing effect on crystal and local structures of doped zirconia using multi probe

Ito, Takanori*; Mori, Masashi*; Inukai, Manabu*; Nitani, Hiroaki*; Yamamoto, Takashi*; Miyanaga, Takashi*; Igawa, Naoki; Kitamura, Naoto*; Ishida, Naoya*; Idemoto, Yasushi*

Photon Factory News, 33(1), p.18 - 24, 2015/05

The effect of the annealing on the crystal and local structures of doped zirconia was investigated by multi-probe technique using synchrotron X-ray and neutron diffraction, and first principles calculation. It was revealed that the annealing process enhances the periodic distortion of some zirconia compounds by Rietveld/ maximum entropy methods applied to the SR-X-ray and neutron diffractions. In addition, the combined X-ray absorption spectroscopy and first-principles calculations results showed the ZrO$$_{8}$$ polyhedra in zirconia were distorted by the annealing. Those results indicate that the degradation of oxide ionic conductivity by the annealing was related to the periodic distortion in zirconia.

Journal Articles

Effect of annealing on crystal and local structures of doped zirconia using experimental and computational methods

Ito, Takanori*; Mori, Masashi*; Inukai, Manabu*; Nitani, Hiroaki*; Yamamoto, Takashi*; Miyanaga, Takashi*; Igawa, Naoki; Kitamura, Naoto*; Ishida, Naoya*; Idemoto, Yasushi*

Journal of Physical Chemistry C, 119(16), p.8447 - 8458, 2015/04

 Times Cited Count:13 Percentile:48.36(Chemistry, Physical)

The effects of the annealing process on the crystal and local structures of the doped zirconia were investigated by Rietveld refinements of synchrotron X-ray and neutron diffraction, maximum entropy method (MEM), X-ray absorption spectroscopy (XAS) and first principles calculation (FPC). This study reveals that the crystal structures of the sintered and annealed ((Zr$$_{0.85}$$Y$$_{0.15}$$)O$$_{2}$$ and (Zr$$_{0.81}$$Sc$$_{0.18}$$Ce$$_{0.01}$$)O$$_{2}$$) are cubic with the space ${it Fm}$-3${it m}$ having large atomic displacement parameters (${it U}$). For the annealed (Zr$$_{0.85}$$Y$$_{0.15}$$)O$$_{2}$$, the ${it U}$ values reduce, and the electrons around the Zr/oxide ion sites gather at the center of each site. On the other hand, the annealed (Zr$$_{0.81}$$Sc$$_{0.18}$$Ce$$_{0.01}$$)O$$_{2}$$ shows the opposite tendency to that of the annealed (Zr$$_{0.85}$$Y$$_{0.15}$$)O$$_{2}$$.

Journal Articles

Protonic conduction, crystal and electronic structures of La$$_{0.9}$$Ba$$_{1.1}$$Ga$$_{0.95}$$Mg$$_{0.05}$$O$$_{4-delta}$$

Hamao, Naoki*; Kitamura, Naoto*; Ito, Takanori*; Igawa, Naoki; Idemoto, Yasushi*; Daido, Hiroyuki; Kaku, Masanori*; Kubodera, Masakazu*

Solid State Ionics, 253, p.123 - 129, 2013/12

 Times Cited Count:3 Percentile:17.78(Chemistry, Physical)

La$$_{0.9}$$Ba$$_{1.1}$$Ga$$_{0.95}$$Mg$$_{0.05}$$O$$_{4-delta}$$ which is one of the candidates for solid electrolyte of solid oxide fuel cell was synthesized by means of a conventional solid-state reaction, and investigated by conductivity measurements, the Rietveld and maximum entropy method analyses using neutron and synchrotron X-ray diffraction data. Conductivity measurements indicated that simultaneous Ba and Mg substitutions for LaBaGaO$$_{4}$$ were effective way to improve the protonic conductivity. From the Rietveld and maximum entropy method analyses, it was confirmed that La$$_{0.9}$$Ba$$_{1.1}$$Ga$$_{0.95}$$Mg$$_{0.05}$$O$$_{4-delta}$$ kept the same crystal structure as LaBaGaO$$_{4}$$ even at elevated temperature, i.e. 1000 K, and that protons existed around the O3 site and formed hydrogen bonds. It is also found that oxygens in LaBaGaO$$_{4}$$-based samples formed Ga-O$$_{4}$$ tetrahedra, and the bonding strength was varied by the partial substitutions.

Journal Articles

Applicability of iron phosphate glass medium for loading NaCl originated from seawater used for cooling the stricken power reactors

Kobayashi, Hidekazu; Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 6 Pages, 2013/09

no abstracts in English

Journal Articles

Behaviour of IPG waste forms bearing BaSO$$_{4}$$ as the dominant sludge constituent generated from the treatment of water used for cooling the stricken power reactors

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 8 Pages, 2013/09

The great amount of water used for cooling the stricken power reactors at Fukushima Dai-ichi has resulted in accumulation of "remaining water". As the remaining water is subsequently contaminated by FPs, etc., it is necessary to decontaminate it in order to reduce the volume of liquid radioactive waste and to reuse it again for cooling the reactors. Various techniques are being applied to remove FP, etc. and to make stable waste forms. One of the methods using the iron phosphate glass as a medium is being developed to stabilize the strontium-bearing sludge whose main component is BaSO$$_{4}$$. From the results hitherto, the iron phosphate glass is regarded as a potential medium for the target sludge.

Journal Articles

Relationship between hypocentral distribution and geological structure in the Horonobe area, northern Hokkaido, Japan

Tokiwa, Tetsuya; Asamori, Koichi; Hiraga, Naoto*; Yamada, Osamu; Moriya, Hirokazu*; Hotta, Hikaru*; Kitamura, Itaru*; Yokota, Hideharu

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.117 - 122, 2010/10

In this paper, we discuss the relationship between the accurate hypocentral distribution and 3-D geological structure in and around the Horonobe area, Japan. We carried out multiplet-clustering analysis by using data of the 421 micro-earthquakes which occurred from 1st September, 2003 to 30th September, 2007. The 3-D geological structure model was mainly constructed from previous seismic reflection profiles and drilling data. As a result of this analysis, although there are some differences in depth between them, the hypocenters are distributed in NNW-SSE direction and become deeper from the west toward the east. The distributed pattern of the hypocenters is similar to the one of the geological structure. These results indicate that the hypocentral distribution may represent existence of active zone related to the geological structure, and provide effective information which can contribute to establishing methods for estimating the future evolution of the geological environment.

Journal Articles

Study of oxygen ion diffusion in (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33-delta}$$ through ${it in-situ}$ neutron diffractions at 300 and 720 K

Ito, Takanori*; Hirai, Takene*; Yamashita, Junichi*; Watanabe, Shoji*; Kawata, Etsuya*; Kitamura, Naoto*; Idemoto, Yasushi*; Igawa, Naoki

Physica B; Condensed Matter, 405(8), p.2091 - 2096, 2010/04

 Times Cited Count:13 Percentile:53.76(Physics, Condensed Matter)

We analyze the mechanism of oxygen ion diffusion in (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33-delta}$$ by using the Rietveld refinement, the maximum entropy method (MEM) analysis, and MEM-based pattern fitting (MPF) with ${it in-situ}$ neutron diffractions at 300 and 720 K. We speculate that when $$U$$$$_{rm aniso}$$ and neutron scattering density of O1(4${it c}$) site with a large number of vacancies metamorphose into that with anisotropy directed toward the O1(4${it c}$) and O2(8${it d}$) sites at 720 K, the oxygen ions diffuse along the paths between O1(4${it c}$) and O1(4${it c}$), and O1(4${it c}$) and O2(8${it d}$).

Journal Articles

Study of mechanism of mixed conduction due to electrons and oxygen ions in (La$$_{0.75}$$Sr$$_{0.25}$$)MnO$$_{3.00}$$ and (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33}$$ through rietveld refinement and MEM analysis

Ito, Takanori*; Shirasaki, Saori*; Fujie, Yoshinori*; Kitamura, Naoto*; Idemoto, Yasushi*; Osaka, Keiichi*; Hirosawa, Ichiro*; Igawa, Naoki

Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 77(2), p.161 - 168, 2009/02

 Times Cited Count:2 Percentile:6.13(Electrochemistry)

We analyzed the mechanism of mixed conduction due to electrons and oxygen ions in (La$$_{0.75}$$Sr$$_{0.25}$$)MnO$$_{3.00}$$ and (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33}$$ through the Rietveld refinement and maximum entropy method analyses of neutron and synchrotron X-ray diffractions. It was found that Mn-O plane in (La$$_{0.75}$$Sr$$_{0.25}$$)MnO$$_{3.00}$$ has a strong, isotropic covalent bond that enables conduction of electrons. The (Co, Fe)-O2 plane with a covalent bond and a low concentration of oxygen vacancies in (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33}$$ can also conduct electrons. On the other hand, the (Ba, Sr)-O1 plane in (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33}$$, which has a high concentration of oxygen vacancies, large isotropic displacement parameter, and a strong ionic bond, is responsible for the diffusion of oxygen ions.

Journal Articles

Determination of crystal structure and charge density of (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33}$$ by Rietveld refinement and maximum entropy method analysis

Ito, Takanori*; Nishida, Yuki*; Tomita, Aya*; Fujie, Yoshinori*; Kitamura, Naoto*; Idemoto, Yasushi*; Osaka, Keiichi*; Hirosawa, Ichiro*; Igawa, Naoki

Solid State Communications, 149(1-2), p.41 - 44, 2009/01

 Times Cited Count:33 Percentile:77.94(Physics, Condensed Matter)

The crystal structure and charge density of (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{2.33}$$ were investigated by the Rietveld refinement method and the maximum entropy method by using neutron and synchrotron X-ray diffraction. The crystal structure was refined by using the split atom model to cation sites with the space group, ${it Pnma}$. The site occupancies of O1(4${it c}$) and O2(8${it d}$) sites were 0.59 and 0.87, respectively. It was found that the (Co, Fe)-O2 plane in the sample has anisotropic covalent and ionic bands, and that the (Ba, Sr)-O1 bond was ionic with a low charge density.

Journal Articles

Development of elevated temperature structural design standard and three-dimensional seismic isolation technology for advanced nuclear power plant

Inoue, Kazuhiko*; Shibamoto, Hiroshi*; Takahashi, Kenji; Ikutama, Shinya*; Morishita, Masaki; Aoto, Kazumi; Kasahara, Naoto; Asayama, Tai; Kitamura, Seiji

Nihon Genshiryoku Gakkai-Shi, 48(5), p.333 - 338, 2006/05

no abstracts in English

JAEA Reports

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

Oral presentation

Development of elevated temperature structural design standard and three-dimensional seismic isolation technology for advanced nuclear power plant

Inoue, Kazuhiko*; Shibamoto, Hiroshi*; Takahashi, Kenji*; Ikutama, Shinya*; Morishita, Masaki; Aoto, Kazumi; Kasahara, Naoto; Asayama, Tai; Kitamura, Seiji

no journal, , 

no abstracts in English

Oral presentation

Study of electron-oxide ion mixed conduction in SOFC cathode materials by MEM

Ito, Takanori*; Yokote, Takenori*; Kitamura, Naoto*; Idemoto, Yasushi*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki

no journal, , 

The investigation and development of the cathode materials are one of the major subjects to decrease the operation temperature for solid oxide fuel cell. In this study, we measured the neutron and synchrotron X-ray diffraction of La$$_{0.73}$$Sr$$_{0.24}$$MnO$$_{3}$$ and (Ba$$_{0.5}$$Sr$$_{0.5}$$)(Co$$_{0.8}$$Fe$$_{0.2}$$)O$$_{3-delta}$$. We discuss the mechanism of the electron-oxide ion mixed conduction from the Rietveld and the maximum entropy method analyses.

Oral presentation

Crystal structure of SOFC cathode materials by neutron and synchrotron X-ray diffraction

Ito, Takanori*; Yokote, Takenori*; Kitamura, Naoto*; Idemoto, Yasushi*; Sakuma, Takashi*; Takahashi, Haruyuki*; Igawa, Naoki

no journal, , 

Perovskite-type oxides with electron-oxide ion mixed conduction are attractive materials as a cathode for solid oxide fuel cell. Although (La,Sr)MnO$$_{3}$$ is applied for this purpose, (Ba,Sr)(Co,Fe)O$$_{3-delta}$$ has much attention because it has lower operation temperature. In this study, we carried out the neutron and synchrotron X-ray diffraction study on those materials, and discuss the difference in crystal structure including the nuclei and electron distribution on the transition metal-oxygen plain in the crystal from the results of the Rietveld and the maximum entropy method analyses.

Oral presentation

Measurement procedure and evaluation on the clearance at FUGEN, 1; Applicability of the procedure based on the results of contamination survey

Hayashi, Hirokazu; Mori, Naoto; Kitamura, Koichi; Sano, Kazuya

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 5; Fundamental experiment on vitrification of NaCl by the IPG medium

Kobayashi, Hidekazu; Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 4; Fundamental experiment on vitrification of BaSO$$_{4}$$ by the IPG medium

Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

no abstracts in English

Oral presentation

Applicability of vitrification method for waste generated from treatment of contaminated water, 6; Fundamental experiment on vitrification of ferrocyanide constituent by the IPG medium

Kobayashi, Hidekazu; Amamoto, Ippei; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto*; Takebe, Hiromichi*; Mitamura, Naoki*; Tsuzuki, Tatsuya*

no journal, , 

no abstracts in English

37 (Records 1-20 displayed on this page)