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Sudo, Katsuo; Takano, Tatsuo; Takeuchi, Kentaro; Kihara, Yoshiyuki; Kato, Masato
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
Japan Atomic Energy Agency has been contracted to advance the Fast Reactor Cycle Technology Development project. As one part of the project, a simplified MOX pellet fabrication method has been developed for fast reactor fuels. In previous reports, feasibility of a simplified MOX pellet fabrication method was confirmed through hot and cold laboratory-scale experiments. The die wall lubrication pressing technology was one of the important technologies included in the development of the simplified MOX pellet fabrication method. In the work described here, a pressing machine with a die wall lubrication system was developed, and MOX pellet fabrication experiments were carried out on the kilogram MOX scale.
Takano, Tatsuo; Sudo, Katsuo; Takeuchi, Kentaro; Kihara, Yoshiyuki; Kato, Masato
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 7 Pages, 2011/12
Development of high burn-up fuels is essential to improve economy of the fast reactor fuel cycle. Increase of fuel burn-up is known to cause fuel-cladding chemical interaction (FCCI) and it mainly determines a lifetime of fuel pin. In order to extend a lifetime of fuel pin by mitigating FCCI, development of low oxygen-to-metal (O/M) MOX fuel has been carried out in plutonium fuel development center of JAEA. MOX fuel needs adjustment of the O/M ratio to less than 1.97 for high burn-up of 150 GWd/t. Therefore, O/M adjustment technology is one of the main subjects in development of a simplified MOX pellet fabrication method which has been advanced in the FaCT (Fast reactor Cycle Technology development) project. In previous work, changes in O/M ratio of MOX pellet during heat treatment were calculated from measurement results of oxygen potentials. On the basis of above calculation, heating tests were carried out to prepare low O/M ratio MOX pellets on a laboratory scale. The O/M ratios obtained in the heating tests were well consistent with calculation results. In the present study, a kilogram MOX scale furnace to adjust O/M ratio of MOX pellets for targeted value has been developed as next step.
Hirooka, Shun; Kato, Masato; Takeuchi, Kentaro; Takano, Tatsuo
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12
In this work, the shrinkage behavior and O/M change of MOX pellet during sintering process were investigated with dilatometer and thermo-gravimeter, and equations to analyze the sintering behavior were derived. The derived equations represented the change of density and O/M ratio of MOX pellet during heat treatment as functions of heat treatment conditions such as heating rate, holding temperature and 
/
ratio in an atmosphere. They contribute the development of advanced pellet production process and would accurately control density and O/M ratio of MOX pellets.
Nagata, Shinji*; Inoue, Aichi; Yamamoto, Shunya; Tsuchiya, Bun*; Takano, Katsuyoshi; To, Kentaro*; Shikama, Tatsuo*
Journal of Alloys and Compounds, 446-447, p.558 - 561, 2007/10
Times Cited Count：20 Percentile：69.88(Chemistry, Physical)The effect of the composition of non-stoichiometric WO
films on the gasochromic coloration are investigated. The films are prepared by a reactive RF magnetron sputtering with varying oxygen partial pressure. To determine the quantitative composition of deposited films, Rutherford backscattering spectroscopy (RBS) and Elastic recoil detection (ERD) are employed. Gasochromic coloration of the films coated with Pd catalyst is examined by optical transmission in hydrogen gas. O/W atomic ratio of the films increases from 0.25 to 3.0 with increasing the oxygen partial pressure in the sputtering gas. H/W ratio increases up to 0.7 with increasing the O/W ration. As regards gasochromic coloration, the film with O/W atomic ratio of 3.0 shows superior coloration performance comparing with that of less than 3.0. Therefore, it is assumed that the good gasochromic coloration of tungsten oxide films is realized by near-stoichiometric WO. In addition, gasochromic coloration state, increasing of hydrogen concentration in WO films is observed. It indicates that gasochromic coloration of WO is relate to formation of HWO structure.
Kato, Masato; Nakamichi, Shinya; Takano, Tatsuo
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.916 - 920, 2007/09
no abstracts in English
Hoesch, M.*; Fukuda, Tatsuo; Mizuki, Junichiro; Takenouchi, Tomohiro*; Kawarada, Hiroshi*; Sutter, J. P.*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Nagao, Masanori*; Takano, Yoshihiko*
Physical Review B, 75(14), p.140508_1 - 140508_4, 2007/04
Times Cited Count：35 Percentile：77.49(Materials Science, Multidisciplinary)We observed phonon dispersions using inelastic X-ray scattering from CVD-grown high quality superconducting (
=4.2 K) boron-doped and non-doped diamonds. By comparing these two, we found almost no change in the acoustic branch along both [111] and [001] directions. On the other hand, strong softening were observed in the optical branch of the boron-doped diamond in both directions: about 2 meV at Brillouin zone boundary and 8 meV at zone center (
point). From this result we estimated the electron-phonon coupling factor 
=0.33, and this supports theoretical models suggesting a phonon-mediated pairing mechanism via coupling of optical phonon modes to Fermi surfaces around the point.
filmsInoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Takano, Katsuyoshi; Yoshikawa, Masahito; Shikama, Tatsuo*
Transactions of the Materials Research Society of Japan, 32(1), p.107 - 110, 2007/03
We investigated the gasochromic coloration of amorphous tungsten oxide films having compositions between WO
and WO
. The films were deposited on SiO
or glassy carbon substrates by the reactive radio frequency (r. f.) magnetron sputtering with varying oxygen partial pressure. The oxygen and hydrogen concentration of the tungsten oxide films were determined using the Rutherford Backscattering Spectrometry (RBS) and the Elastic Recoil Detection Analysis (ERDA), respectively. The optical transmission was examined for the films coated with palladium catalysis during the exposure of diluted hydrogen gas. Superior gasochromic properties were obtained for the films consisting of tungsten trioxide WO. For the films with lower oxygen concentration than WO, the optical transmission hardly changed during the hydrogen exposure. A large concentration of hydrogen about 0.7 per a tungsten atom was found in the WO films. The hydrogen retention drastically decreased with a decrease of the oxygen concentration.
Inoue, Aichi; Nagata, Shinji*; Shikama, Tatsuo*; Yamamoto, Shunya; Takano, Katsuyoshi
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 147, 2007/02
no abstracts in English
Nagata, Shinji*; Yamamoto, Shunya; Inoue, Aichi; Tsuchiya, Bun*; To, Kentaro*; Takano, Katsuyoshi; Yoshikawa, Masahito; Shikama, Tatsuo*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 148, 2007/02
no abstracts in English
= 1 antiferromagnet observed by specific heat measurementsHagiwara, Masayuki*; Tsujii, Hiroyuki*; Rotundu, C. R.*; Andraka, B.*; Takano, Yasumasa*; Tateiwa, Naoyuki; Kobayashi, Tatsuo*; Suzuki, Takafumi*; Suga, Seiichiro*
Physical Review Letters, 96(14), p.147203_1 - 147203_4, 2006/04
Times Cited Count：18 Percentile：67.26(Physics, Multidisciplinary)Specific-heat experiments on single crystals of the = 1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C
H
N
)(NO
)(ClO) (NTENP) have been performed in magnetic fields applied both parallel and perpendicular to the spin chains. We have found for the parallel field configuration that the magnetic specific heat (
) is proportional to temperature (
) above a critical field 
, at which the energy gap vanishes, in a temperature region above that of the long-range ordered state. The ratio = increases as the magnetic field approaches from above. The data are in good quantitative agreement with the prediction of the 
=1 conformal field theory in conjunction with the velocity of the excitations calculated by a numerical diagonalization, providing conclusive evidence for a Tomonaga-Luttinger liquid.
Fukuda, Tatsuo; Hoesch, M.*; Takenouchi, Tomohiro*; Sutter, J. P.*; Tsutsui, Satoshi*; Baron, A.*; Nagao, Masanori*; Takano, Yoshihiko*; Kawarada, Hiroshi*; Mizuki, Junichiro
no journal, ,
Diamond is well known for its maximum hardness, large energy gap, high thermal conductivity, and so on. In addition to these, the superconductivity was discovered recently in boron doped (B-doped) diamond, and this was soon confirmed by other groups. We performed inelastic X-ray scattering experiments at BL35XU of SPring-8 to measure phonons in a highly B-doped CVD grown diamond having superconducting transition at 
4.2 K. By comparing the experimental results with those from nitrogen doped CVD grown diamond and/or pure diamond, we found that the optical modes are softened especially at around the Brillouin zone center along with a strong broadening, while the acoustic modes do not show both softening and broadening. This confirms the strong electron-phonon coupling in superconducting diamond.
Inoue, Aichi; Nagata, Shinji*; Shikama, Tatsuo*; Yamamoto, Shunya; Takano, Katsuyoshi; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Nagata, Shinji*; Inoue, Aichi; To, Kentaro*; Tsuchiya, Bun*; Shikama, Tatsuo*; Yamamoto, Shunya; Takano, Katsuyoshi; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Inoue, Aichi; Takano, Katsuyoshi; Yamamoto, Shunya; Nagata, Shinji*; Shikama, Tatsuo*
no journal, ,
no abstracts in English
Inoue, Aichi; Takano, Katsuyoshi; Yamamoto, Shunya; Nagata, Shinji*; Shikama, Tatsuo*
no journal, ,
no abstracts in English
Nagata, Shinji*; To, Kentaro*; Tsuchiya, Bun*; Shikama, Tatsuo*; Yamamoto, Shunya; Takano, Katsuyoshi; Inoue, Aichi
no journal, ,
no abstracts in English
filmsInoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Takano, Katsuyoshi; Yoshikawa, Masahito; Shikama, Tatsuo*
no journal, ,
no abstracts in English
Inoue, Aichi; Takano, Katsuyoshi; Yamamoto, Shunya; Nagata, Shinji*; Shikama, Tatsuo*
no journal, ,
no abstracts in English
Inoue, Aichi; Takano, Katsuyoshi; Yamamoto, Shunya; Nagata, Shinji*; Shikama, Tatsuo*
no journal, ,
no abstracts in English
Nagata, Shinji*; Tsuchiya, Bun*; To, Kentaro*; Shikama, Tatsuo*; Inoue, Aichi; Yamamoto, Shunya; Takano, Katsuyoshi
no journal, ,
no abstracts in English
