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Ikeda, Kazutaka*; Sashida, Sho*; Otomo, Toshiya*; Oshita, Hidetoshi*; Honda, Takashi*; Hawai, Takafumi*; Saito, Hiraku*; Ito, Shinichi*; Yokoo, Tetsuya*; Sakaki, Koji*; et al.
International Journal of Hydrogen Energy, 51(Part A), p.79 - 87, 2024/01
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)Tang, J.*; Seo, O.*; Rivera Rocabado, D. S.*; Koitaya, Takanori*; Yamamoto, Susumu*; Namba, Yusuke*; Song, C.*; Kim, J.*; Yoshigoe, Akitaka; Koyama, Michihisa*; et al.
Applied Surface Science, 587, p.152797_1 - 152797_8, 2022/06
Times Cited Count：7 Percentile：77.62(Chemistry, Physical)The hydrogen absorption and diffusion mechanisms on cube-shaped Pd nanoparticles (NPs) which are important hydrogen-storage materials were studied using X-ray photoelectron spectroscopy and DFT calculations. In the surface region, hydrogen absorption showed almost similar behavior regardless of the NPs size. It was found that the octahedral sites are more favorable than the tetrahedral sites for hydrogen occupation. We also clarified that the hydrogen atoms absorbing on the smaller-sized Pd NPs diffuse to the subsurface more actively because of the weakened Pd-H bond by the surface disordering, which plays an important role in hydrogen adsorption at a low H
pressure.
dispersive X-ray absorption fine structure spectroscopySong, C.*; Seo, O.*; Matsumura, Daiju; Hiroi, Satoshi*; Cui, Y.-T.*; Kim, J.*; Chen, Y.*; Tayal, A.*; Kusada, Kohei*; Kobayashi, Hirokazu*; et al.
RSC Advances (Internet), 10(34), p.19751 - 19758, 2020/05
Times Cited Count：0 Percentile：0(Chemistry, Multidisciplinary)Tang, J.*; Yamamoto, Susumu*; Koitaya, Takanori*; Yoshigoe, Akitaka; Tokunaga, Takuma*; Mukai, Kozo*; Matsuda, Iwao*; Yoshinobu, Jun*
Applied Surface Science, 480, p.419 - 426, 2019/06
Times Cited Count：10 Percentile：49.82(Chemistry, Physical)Mass transports during hydrogen adsorption and absorption processes of PdCu alloys that has advantages of higher hydrogen diffusivity and economically lower-cost than the other Pd-alloys were studied. The research was made with a comparison of the well-known ordered phase of the bcc structure (the B2 phase) and a mixed phase of the fcc and B2 structures. 
ultrahigh vacuum X-ray photoelectron spectroscopy and ambient pressure X-ray photoelectron spectroscopy using synchrotron radiation were carried out to trace the chemical states of the Pd and Cu atoms as a function of temperatures. It is elucidated that the initial adsorption and absorption processes were similar in the two phases, but a hydrogen diffusion rate to the bulk was higher in the ordered phase than in the mixed one. We found the dynamics of the Pd and Cu atoms during the hydrogen adsorption/absorption processes largely depend on temperature. In the hydrogen atmosphere, the Pd atoms segregate at the surface below 373 K and Cu atoms segregate at the surface above 373 K. The present results agree well with the previous theoretical calculations and, thus, provide appropriate inputs toward developments of the hydrogen permeation materials.
Kurata, Masaki; Barrachin, M.*; Haste, T.*; Steinbrueck, M.*
Journal of Nuclear Materials, 500, p.119 - 140, 2018/03
Times Cited Count：29 Percentile：66.35(Materials Science, Multidisciplinary)Severe accidents occurred at the Fukushima-Daiichi Nuclear Power Station (FDNPS) required an immediate re-examination of fuel degradation phenomenology. The present paper reviews the updated knowledge on the phenomenology of the fuel degradation, focusing mainly on the BWR fuel assembly degradation at the macroscopic scale and that of the individual interactions at the meso-scale. Oxidation of boron carbide (B
C) control rods potentially generate far larger amounts of heat and hydrogen under BWR accident conditions. All integral tests with BC control rods or control blades have shown early failure, liquefaction, relocation and oxidation of BC starting at temperatures around 1250
C, well below the significant interaction temperatures of UO-Zry. These interactions or reactions potentially influence the progress of fuel degradation in the early phase. The steam-starved conditions, which are being discussed as a likely scenario at the FDNPS accident, highly influence the individual interactions and potentially lead the fuel degradation in non-prototypical directions. The detailed phenomenology of individual interactions and their influence on the transient and on the late phase of the severe accidents are also discussed.
Kofu, Maiko; Hashimoto, Naoki*; Akiba, Hiroshi*; Kobayashi, Hirokazu*; Kitagawa, Hiroshi*; Iida, Kazuki*; Nakamura, Mitsutaka; Yamamuro, Osamu*
Physical Review B, 96(5), p.054304_1 - 054304_7, 2017/08
Times Cited Count：15 Percentile：58.3(Materials Science, Multidisciplinary)The vibrational states of hydrogen atoms in bulk and nanocrystalline palladium were examined in a wide energy region 
meV using neutron spectroscopy. In bulk PdH
, the vibrational excitations of H atoms were roughly reproduced by the quantum harmonic oscillator (QHO) model. In PdH
nanocrystals with a diameter of 8 nm, however, additional vibrational excitations were found at energies above 80 meV. The energies and intensities of the additional states were not explained by QHO but reasonably described as vibrations in a highly anharmonic trumpet-like potential. The additional excitations are attributed to the vibrations of H atoms at tetrahedral sites in the subsurface region stabilized by surface effects. This is an experimental work which clearly detects hydrogen vibration 
metal nanoparticles.
Abe, Hiroshi; Shimomura, Takuya; Tokuhira, Shinnosuke*; Shimada, Yukihiro*; Takenaka, Yusuke*; Furuyama, Yuta*; Nishimura, Akihiko; Uchida, Hirohisa*; Daido, Hiroyuki; Oshima, Takeshi
Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08
A short pulse laser (the nanosecond and femtosecond) was applied to hydrogen absorbing alloys surface layer, and a surface modification experiment was put into effective to aim at improvement of hydrogen adsorption functionally. It was investigated about correlation between an initial hydrogen absorption reaction rate of hydrogen alloys and a laser irradiation in this research. The laser irradiation condition was done with pulse width 100 fsec and energy 0.2 - 3.4 mJ/pulse. It blazed down on hydrogen absorbing alloys (LaNi
Al
) and changed local order in the surface. As a result, the initial hydrogen absorption reaction rate was 1.5 - 3.0 times as fast as a irradiated sample, and the result and laser irradiated sample found out that a hydrogen absorption function improves. A laser irradiation can conclude to be effective in surface modification of the hydrogen storage materials.
Abe, Hiroshi; Morimoto, Ryo*; Sato, Fumiatsu*; Azuma, Yorito*; Uchida, Hirohisa*
Journal of Alloys and Compounds, 408-412, p.348 - 350, 2006/02
Times Cited Count：10 Percentile：54.65(Chemistry, Physical)Mm(misch metal) based hydrogen storage alloys are applied to the negative electrode of the Ni-H battery and other hydrogen storage systems. In such pratical applications, various surface processes of hydrogen molecules often become rate contolling. Therefore, the improvement of the alloy surface is of great importance to promote the initial activation and hydriding rate. We have reported that the alkaline pretreatment of an alloy surfece exhibits a high durability against CO attack. Since low energy ion irradiation is quite useful for surface modification of materials, the hydriding proerties of a Mm is expected on electrochemical hydriding rate of the alloy. As a result, the ion irradiation Mm was found to induce a higher hydriding rate than that of the un-irradiation one.
Yamaguchi, Kaoru*; Yamauchi, Yuji*; Hirohata, Yuko*; Hino, Tomoaki*; Tsuzuki, Kazuhiro
Shinku, 46(5), p.449 - 452, 2003/05
no abstracts in English
Matsubayashi, Masahito
Hihakai Kensa No Saizensen (CD-ROM), 7 Pages, 2002/00
no abstracts in English
Taniguchi, Naoki; Kawasaki, Manabu*; Fujiwara, Kazuo*
JNC TN8400 2001-011, 62 Pages, 2001/03
JNC-TN8400-2001-011.pdf:5.67MB
The corrosion of metallic materials used in natural environment are sometimes affected by microbial action. It is apprehended that microorganism living in deep underground or brought from ground surface during excavation makes an impact on overpack material for geological disposal of high-level radioactive waste. Sulfate reducing bacteria (SRB) is known to be one of the most representative microorganism which affects the corrosion of metals. In this study, the behavior of growth of SRB was investigated at first under the presence of bentonite as a main component of buffer material which encloses the overpack. The results of the tests showed that the population of SRB after the culture in synthetic sea water mixed with bentonite decreased with increasing the ratio of bentonite/solution. SRB was hardly grown in medium whose bentonite/solution ratio exceeded 1000g/l. As a conservative case, the effects of sulfide on the corrosion of overpack materials were also studied assuming high activity of SRB. Carbon steel, copper and titanium specimens were immersed in synthetic sea water purging 0.1MPa HS gas and the corrosion behavior was compared with the results in N gas purging environment. Obvious effect of sulfide on the corrosion of carbon steel was not observed, but the corrosion rates of copper specimens were accelerated several hundred times by purging HS gas. The absorption of hydrogen into titanium specimens was not affected by purging HS gas, but the difference of hydrogen absorption between pure titanium and titanium alloy containing 0.06%-Pd was observed.
Ogawa, Hiroaki; Saburi, Tei; Kiuchi, Kiyoshi
JAERI-Research 2000-055, 57 Pages, 2000/11
JAERI-Research-2000-055.pdf:3.73MB
no abstracts in English
Sakaguchi, Hiroki*; Hatakeyama, Keisuke*; Satake, Yuichi*; Fujine, Shigenori*; Yoneda, Kenji*; Kanda, Keiji*; Matsubayashi, Masahito; Esaka, Takao*
Kashika Joho Gakkai-Shi, 20(suppl.1), p.373 - 374, 2000/07
no abstracts in English
Ishiyama, Shintaro; Fukaya, Kiyoshi; Eto, Motokuni; Miya, Naoyuki
Journal of Nuclear Science and Technology, 37(2), p.144 - 152, 2000/02
no abstracts in English
Tomari, Haruo*; *; Shimogori, Kazutoshi*; Wada, Ryutaro*; ; Taniguchi, Naoki
JNC TN8400 99-076, 100 Pages, 1999/10
Effects of bentonite clay, applied potential, pH, of solution and cathodic polarization time on hydrogen absorption into titanium, which is one of the candidate materials of overpack for high-level radioactive waste container, have been investigated in artificial underground water. Considering the result at various test time and assuming the hydrogen absorption is ruled by the paraboric law, the amount of hydrogen after 1000 years exposure calculated to about 17ppm, which will be absorbed at the applied potential of -0.51 vs. SHE corresponds to equilibrium potential of hydrogen. It seems the assumption of the parabolic law and the test period are proper, because the linear relations were obtained between the amount of absorbed hydrogen and the logarithm of the averaged cathodic current and between the slopes of the lines and a square root of the test time. Titanium seems to have a life over 1000 years in deep underground repository according to assumption that about 500ppm absorbed hydrogen is critical for hydrogen embrittlement of titanium.
Tsujikawa, Shigeo*; *; *; Tsuru, Toru*; Shibata, Toshio*; *
PNC TJ1560 98-001, 164 Pages, 1998/02
None
Takeuchi, Suehiro; Matsuda, Makoto; Ishizaki, Nobuhiro; Tayama, Hidekazu; Ouchi, Isao;
Proceedings of 23rd Linear Accelerator Meeting in Japan, p.121 - 123, 1998/00
no abstracts in English
Tsujikawa, Shigeo*; *; *; Tsuru, Toru*; Shibata, Toshio*; *
PNC TJ1560 97-001, 210 Pages, 1997/03
None
JAERI-Research 97-012, 96 Pages, 1997/03
JAERI-Research-97-012.pdf:8.65MB
no abstracts in English
; ; Kanazawa, Shuhei; ; Ouchi, Isao;
Dai-9-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, 0, p.42 - 44, 1996/00
no abstracts in English
