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-phase zirconium hydrides and deuteridesTsuchiya, Bun*; Yasuda, Ryo; Teshigawara, Makoto; Konashi, Kenji*; Nagata, Shinji*; Shikama, Tatsuo*; Yamawaki, Michio*
Journal of Nuclear Materials, 376(1), p.60 - 65, 2008/05
Times Cited Count：2 Percentile：17.17(Materials Science, Multidisciplinary)Distributions of hydrogen isotope concentrations in e-phase zirconium hydrides and deuterides (-ZrHx and -ZrDx: 1.8 
x 2.0) were investigated by neutron radiography (NRG). The NRG images of the thermal neutron transmission and backscattering revealed hydrogen concentration dependence and isotope differences. The thermal neutron mass attenuation coefficients in relation to the hydrogen isotope concentrations were determined from the transmission NRG images. The results showed the isotope effects of the thermal neutron mass attenuation coefficients for -ZrHx to be about 6-9 times higher than those for -ZrDx. The neutron scattering processes for transmission and backscattering NRG images of -ZrHx and -ZrDx were also analyzed using a general Monte Carlo neutron-particle transport (MCNP) code.
Shimura, Kenichiro*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Journal of Alloys and Compounds, 449(1-2), p.357 - 361, 2008/01
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)no abstracts in English
Luo, G.-N.*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Plasma Science and Technology, 7(4), p.2982 - 2984, 2005/08
no abstracts in English
Shimura, Kenichiro*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Journal of Physics and Chemistry of Solids, 66(2-4), p.684 - 689, 2005/02
Times Cited Count：1 Percentile：7.32(Chemistry, Multidisciplinary)no abstracts in English
Yamawaki, Michio*; Kawamura, Hiroshi; Tsuchiya, Kunihiko
Seramikkusu, 39(10), p.843 - 848, 2004/10
no abstracts in English
TiO
added with TiOHoshino, Tsuyoshi; Kobayashi, Takeshi*; Nashimoto, Makoto*; Kawamura, Hiroshi; Dokiya, Masayuki*; Terai, Takayuki*; Yamawaki, Michio*; Takahashi, Yoichi*
JAERI-Conf 2004-012, p.140 - 147, 2004/07
no abstracts in English
Np Fission Cross Section at YAYOIOki, Shigeo; Takashima, Hideki; Wakabayashi, Toshio; Yamaguchi, Kenji*; Yamawaki, Michio*
JNC TY9400 2004-005, 36 Pages, 2004/05
JNC-TY9400-2004-005.pdf:1.01MB
In the framework of the study on transmutation of minor actinide (MA) nuclides with fast reactors, the fission cross section ratio of 237Np relative to 235U has been measured by using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. The compact BTB fission chamber was prepared for the measurements in the experimental holes called Glory hole and Grazing hole passing though the core center and the side blanket of YAYOI, respectively. Dependence of fission cross section ratios on neutron spectrum was investigated by changing the measurement position in these experimental holes.The measured values of fission cross section ratios were compared with those calculated with the following nuclear data libraries: JENDL-3.2, ENDF/B-VI, JEF-2.2, and JENDL-2. It was found that the calculated values in the center of the core systematically overestimated the measurements by about 30%. Dispersion of the calculated values among the nuclear data libraries was smaller than the above difference from the measured value. We also see the dependence of C/E value on the measurement position. It is hardly said that uncertainty of nuclear data brings about the above overestimation of 30%.The present result remained some issues in terms of the measurement accuracy. If we can get rid of those causes, for example, by means of the unfolding technique on pulse height distribution, the result could be utilized as expletive information in nuclear data validation not only for 237Np, but also for 235U and 238U which characterize the neutron spectrum.
Am, 
Am Fission Cross Sections at YAYOIOkawachi, Yasushi; Oki, Shigeo; Wakabayashi, Toshio; Yamaguchi, Kenji*; Yamawaki, Michio*
JNC TY9400 2004-004, 37 Pages, 2004/05
JNC-TY9400-2004-004.pdf:1.03MB
In the framework of the study on transmutation of minor actinide (MA) nuclides with fast reactors, the fission cross section ratios of MA (241Am, 243Am) relative to 235U have been measured by using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. The compact BTB fission chamber was prepared for the measurements in the main experimental hole (Glory hole) passing though the core of YAYOI. Dependence of fission cross section ratios on neutron spectrum was investigated by changing the measurement position in Glory hole from core center to depleted uranium blanket.The measured values of fission cross section ratios were compared with those calculated with the following nuclear data libraries: JENDL-3.2, ENDF/B-VI, and JEF-2.2. It was found that the calculated values for both 241Am and 243Am in the center of the core systematically underestimated the measurements by 10 to 20%. Dispersion of the calculated values among the nuclear data libraries was smaller than the above difference from the measured value. We also see the dependence of C/E value on the measurement position.The present result remained some issues in terms of the measurement accuracy. If we can get rid of those causes, for example, by means of the unfolding technique on pulse height distribution, the result could be utilized as expletive information in nuclear data validation not only for 241Am and 243Am but also for 235U and 238U which characterize the neutron spectrum.
TiOHoshino, Tsuyoshi; Kobayashi, Takeshi*; Nashimoto, Makoto*; Kawamura, Hiroshi; Terai, Takayuki*; Yamawaki, Michio*; Takahashi, Yoichi*
Journal of the Ceramic Society of Japan, Supplement, Vol.112, No.1 (CD-ROM), p.S354 - S357, 2004/05
no abstracts in English
Yamawaki, Michio*; Konashi, Kenji*; Kono, Shusaku; Kitamura, Ryoich
JNC TY8400 2003-006, 38 Pages, 2003/05
JNC-TY8400-2003-006.pdf:2.66MB
The actinide-hydride fuel is an excellent integral fuel - moderator system. The concentration of hydrogen in the actinide hydride is comparable to that of hydrogen in liquid water of LWR cores. We have proposed new type of reactor core to reduce the amoun
Shimura, Kenichiro*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
JAERI-Conf 2003-001, p.352 - 358, 2003/03
no abstracts in English
Luo, G.-N.*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Journal of Alloys and Compounds, 349(1-2), p.211 - 216, 2003/02
Times Cited Count：8 Percentile：49.66(Chemistry, Physical)Lithium ceramics, Li
O, LiAlO and Li
SiO, under ion or electron beam irradiation have been studied using a Kelvin probe that measures work function changes of materials. Surface charging was observed to influence greatly the probe output, which can be explained qualitatively employing a model concerning polarization effect in insulating ceramics due to free charges on their surfaces. It is found that the insulating ceramics could not be studied properly with the Kelvin probe. A probable solution has been presented, i.e., to heat the ceramics, so as to raise their electric conductivities high enough to root out the surface charges
Shimura, Kenichiro*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Physica Scripta, T103, p.101 - 104, 2003/00
Times Cited Count：2 Percentile：21.48(Physics, Multidisciplinary)In this study, the kinetics of desorption of adsorbed hydrogen from an ideal metallic surface is modeled in Cellular Automaton (CA). The modeling is achieved by downgrading the surface to one dimension. The model consists of two parts that are, surface migration and desorption. The former is attained by randomly sorting the particles at each time, the latter is realized by modeling the thermally-activated process. For the verification of this model, thermal desorption is simulated and then the comparison with the chemical kinetics is carried out. Excellent agreement is observed from the result. The overall results show that this model is reasonable to express the recombinative desorption of two chemisorbed adatoms. Although the application of this model is limited to second-order reaction case, it can be believed that the groundwork of modeling the transport dynamics of hydrogen through the surface under complex conditions is established.
Shimura, Kenichiro*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Journal of Nuclear Materials, 307-311(2), p.1478 - 1483, 2002/12
Times Cited Count：2 Percentile：17.13(Materials Science, Multidisciplinary)no abstracts in English
Kuratomi, Takashi*; Yamaguchi, Kenji; Yamawaki, Michio*; Bak, T.*; Nowotny, J.*; Rekas, M.*; Sorrell, C. C.*
Solid State Ionics, 154-155, p.223 - 228, 2002/12
Times Cited Count：14 Percentile：57.74(Chemistry, Physical)no abstracts in English
Tominaga, Shinya*; Busnyuk, A.*; Matsushima, T.*; Yamaguchi, Kenji; Ono, Futaba*; Terai, Takayuki*; Yamawaki, Michio*
Fusion Science and Technology, 41(3), p.919 - 923, 2002/05
no abstracts in English
Tsuchiya, Bun*; Teshigawara, Makoto; Nagata, Shinji*; Konashi, Kenji*; Yasuda, Ryo; Nishino, Yasuharu; Nakagawa, Tetsuya*; Yamawaki, Michio*
Nuclear Instruments and Methods in Physics Research B, 190(1-4), p.699 - 703, 2002/05
Times Cited Count：10 Percentile：55.15(Instruments & Instrumentation)Practicability of Elastic Recoil Detection (ERD) and Neutron Radiography (NRG) methods for hydrogen concentration in titanium hydrides (d-TiHx : 1.6<x<2.0) is investigated. In ERD methods, the hydrogen concentration in the surface of TiHx is recognized. In NRG method, the hydrogen concentration over the balk was confirmed. These results show that both methods are effective means for estimating the hydrogen concentration in hydride materials.
Luo, G.-N.*; Terai, Takayuki*; Yamawaki, Michio*; Yamaguchi, Kenji
Proceedings of OECD/NEA 2nd Information Exchange Meeting on Basic Studies in the Field of High-temperature Engineering, p.177 - 189, 2002/05
no abstracts in English
Luo, G.-N.*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*
Surface Science, 505, p.14 - 24, 2002/05
Times Cited Count：3 Percentile：20.67(Chemistry, Physical)no abstracts in English
Huang, J.; Furukawa, Tomohiro; Aoto, Kazumi; Yamawaki, Michio*
Journal of the Mass Spectrometry Society of Japan, 50(6), p.296 - 300, 2002/00
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