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Yamazaki, Takumi*; Hirai, Takamasa*; Yagi, Takashi*; Yamashita, Yuichiro*; Uchida, Kenichi*; Seki, Takeshi*; Takanashi, Koki
Physical Review Applied (Internet), 21(2), p.024039_1 - 024039_11, 2024/02
Times Cited Count：0 Percentile：0.01(Physics, Applied)Yokoyama, Keisuke; Uwaba, Tomoyuki
Journal of Nuclear Science and Technology, 60(10), p.1219 - 1227, 2023/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
Nagase, Fumihisa
Annals of Nuclear Energy, 171, p.109052_1 - 109052_8, 2022/06
Times Cited Count：2 Percentile：50.96(Nuclear Science & Technology)The fracture threshold of the fuel decreases if the oxidized Zr alloy cladding is strongly constrained by the spacer grid during quenching in a loss-of-coolant accident. Therefore, the estimation of realistic levels of the axial constraint has been a subject of significant interest on fuel safety. In this study, a test assembly consisting of a PWR-type simulated fuel segment and a 3
3 grid piece was heated in steam, cooled, and quenched, and the axial constraint force on the fuel segment was measured. The constraint force of the Zircaloy grid gradually decreased with temperature. Once the Zircaloy grid was heated to 
1060 K, the reduced constraint force had difficulty recovering, and thus the maximum constraint force during cooling and quenching was 
10 N. The constraint force was clearly reduced at 1070 K during the tests with the Inconel grid. However, the reduced constraint force partially recovered during cooling. As a result, the maximum constraint force during cooling and quenching was 20 to 50 N for the Inconel grid. In conclusion, oxidation, ballooning, rupture, or eutectic formation would not generally cause an extremely strong constraint, as predicted by previous studies, at the grid position.
Toyoda, Satoshi*; Yoshimura, Masashi*; Sumida, Hirosuke*; Mineoi, Susumu*; Machida, Masatake*; Yoshigoe, Akitaka; Yoshikawa, Akira*; Suzuki, Satoru*; Yokoyama, Kazushi*
Hoshako, 35(3), p.200 - 206, 2022/05
The present status of spatiotemporal depth profiling analysis of the multilayer stacked film interface based on Ambient Pressure X-ray Photoelectron Spectroscopy (APXPS) is presented. To begin with, depth profiles of the multilayer stacked film interfaces have been achieved by time-division Near Ambient Pressure Hard X-ray Angle-Resolved PhotoEmission Spectroscopy data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division angle resolved AP-XPS data including spatial resolution, which enables us to realize spatiotemporal depth profiles of the interfaces under reaction conditions such as oxidation and reduction. In addition, it is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling is effective to perform dynamic measurement of depth profiles with high precision.
Uwaba, Tomoyuki; Yokoyama, Keisuke; Nemoto, Junichi*; Ishitani, Ikuo*; Ito, Masahiro*; Pelletier, M.*
Nuclear Engineering and Design, 359, p.110448_1 - 110448_7, 2020/04
Times Cited Count：1 Percentile：11.8(Nuclear Science & Technology)Coupled computer code analyses of irradiation performance of axially heterogeneous mixed oxide (MOX) fuel elements with high burnup in a fast reactor were conducted. Post-irradiation experiments revealed local concentration of Cs near the interfaces between MOX fuel and blanket columns including the internal blanket of the fuel elements as well as an increase in their cladding diameters. The analyses indicated that the local Cs concentration occurred as a result of Cs axial migration from the MOX fuels toward the blanket pellets near the interfaces. Swelling of the blanket pellets induced by the formation of low-density Cs-U-O compound was not sufficient to cause pellet-to-cladding mechanical interaction (PCMI). The PCMI analyzed in the MOX fuel column regions was insignificant, and the cladding diameter increases were caused mainly by void swelling in cladding and irradiation creep due to fission gas pressure.
Hasegawa, Kunio; Li, Y.; Mare
, V.*; Lacroix, V.*
Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 5 Pages, 2018/07
Appendix C-5320 of ASME Code Section XI provides a formula of bending stress at the plastic collapse, where the formula is applicable for both inner and outer surface flaws. Authors considered the separated pipe mean radii at the flawed ligament and at the un-flawed ligament and formulas of plastic collapse stresses for each inner and outer flawed pipe were obtained. It is found that the collapse stress for inner flawed pipe is slightly higher than that calculated by Appendix C-5320 formula, and the collapse stress for outer flawed pipe is slightly lower than that by Appendix C-5320 formula. The collapse stresses derived from the three formulas are almost the same in most instances. For less common case where the flaw angle and depth are very large for thick wall pipes, the differences among the three collapse stresses become large.
Hayano, Akira; Itakura, Kenichi*
Journal of MMIJ, 133(4), p.76 - 86, 2017/04
no abstracts in English
Si with XPS and XASEsaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki
Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07
Times Cited Count：16 Percentile：41.35(Chemistry, Physical)XPS is widely used for non-destructive chemical state analysis of solid materials. In this method, depth profiling can be carried out by a combination with ion beam sputtering. However, the sputtering often causes segregation and preferential sputtering of atoms and gives inaccurate information. The use of energy-tunable X-rays from synchrotron radiation (SR) enables us to perform non-destructive depth profiling in XPS. Here, the analytical depth can be changed by changing excitation X-ray energy. In the present study, we examined methods to perform depth profiling with XPS by changing excitation energy and XAS by changing electron energy for detection. These methods were then applied to the analysis of native surface oxide layers on MgSi crystals. In this XAS analysis, the peak at 1843.4 eV becomes dominant when the electron energy for detection increases, which implies that Si-O or Si-O-Mg structure is formed as the surface oxide layer on the MgSi.
Kobata, Masaaki; Kobayashi, Keisuke*
Journal of the Vacuum Society of Japan, 58(2), p.43 - 49, 2015/02
We report the applications of a hard X-ray photoelectron spectroscopy to the characterization of SiO/Si(001)systems. Large escape depth of high-energy photoelectron enables us to probe buried layers and their interfaces in multilayer structures. Estimation of SiO overlayer thicknesses up to 25 nm by angle resolved XPS was possible in SiO/Si(001) samples. Determination of the thickness profile of a wedged shape SiO buried layer was successfully done in Ir (8 nm)/HfO (2.2 nm)/thickness graded-SiO (0-10 nm) / Si (100). The Si 1s core level showed a SiO thickness dependent shift, which was ascribed to fixed charge at the SiO-Si interface. Energy distribution of interface states at ultrathin thermal oxide/Si(100) interfaces were determined by Si 1
core level shift by applying gate bias in metal-oxide-semiconductor (MOS) structure with 5 nm Au gate electrodes.
Suzuki, Atsuyuki
Risk Analysis, 34(7), p.1240 - 1256, 2014/07
Times Cited Count：14 Percentile：71.01(Public, Environmental & Occupational Health)The Fukushima Daiichi accident raises a fundamental question: Can science and technology prevent the inevitability of serious accidents, especially those with low probabilities and high consequences? This question reminds us of a longstanding challenge with the trans-sciences, originally addressed by Alvin Weinberg well before the Three Mile Island and Chernobyl accidents. This paper, revisiting Weinberg's issue, aims at gaining insights from the accident with a special emphasis on the socio-technical or human behavioral aspects lying behind the accident's causes. In particular, an innovative method for managing the challenge is explored referring to behavioral science approaches for a decision-making process on risk management; such as managing human behavioral risks with information asymmetry, seeking a rational consensus with communicative action, and pursuing procedural rationality through interactions with the outer environment. In short, this paper describes the emerging needs for Japan to transform its national safety management institutions so that these might be based on interactive communication with parties inside and outside Japan.
Tsuchiya, Katsuhiko; Kizu, Kaname; Takahashi, Hiroyuki*; Ando, Toshinari*; Matsukawa, Makoto; Tamai, Hiroshi
IEEE Transactions on Applied Superconductivity, 16(2), p.922 - 925, 2006/06
Times Cited Count：1 Percentile：11.94(Engineering, Electrical & Electronic)no abstracts in English
Ueshima, Yutaka
Chiiki Kenkyu Koryu, 21(1), p.2 - 5, 2005/06
no abstracts in English
Oshima, Takeshi; Lee, K. K.; Ishida, Yuki*; Kojima, Kazutoshi*; Tanaka, Yasunori*; Takahashi, Tetsuo*; Yoshikawa, Masahito; Okumura, Hajime*; Arai, Kazuo*; Kamiya, Tomihiro
Materials Science Forum, 457-460(Part2), p.1405 - 1408, 2004/06
The electrical characteristics of cubic silicon carbide (3C-SiC) Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) with the current direction in the inversion layer perpendicular to [-110] ([-110]-perpendicular MOSFETs) were compared to those of 3C-SiC MOSFETs with the current direction in the inversion layer parallel to [-110] ([-110]-parallel MOSFETs). The threshold voltage (V
) for both MOSFETs shows -0.5 V although enhancement type MOSFETs were designed. The values of channel mobility which was estimated from linear region of drain current (I
) - drain voltage (V) curves are 230 cm
/Vs for [-110]-perpendicular MOSFETs and 215 cm/Vs for [-110]-parallel MOSFETs, indicating no significant difference between both MOSFETs. The value of I for [-110]-perpendicular MOSFETs is of order of 10-8 A at V = 10V and gate voltage (V
) of -2V. However, for [-110]-parallel MOSFETs, I shows of order of -10-6 A at V = 10V and V = -2V.
-FeSi thin films on Si(III) surface by solid phase epitaxy (SPE) analyzed by means of synchrotron radiation XPS (SR-XPS)Saito, Takeru; Yamamoto, Hiroyuki; Asaoka, Hidehito; Haraguchi, Masaharu*; Imamura, Motoyasu*; Matsubayashi, Nobuyuki*; Tanaka, Tomoaki*; Shimada, Hiromichi*; Hojo, Kiichi
Analytical Sciences (CD-ROM), 17(Suppl.), p.1073 - 1076, 2002/03
no abstracts in English
*;
JNC TN8430 2001-006, 65 Pages, 2001/10
JNC-TN8430-2001-006.pdf:15.23MB
We had been conducted to study hydraulic permeability along fracture intersection by NETBLOCK system using natural rock specimen. Since the permeability of this rock specimen fracture is high, it was suggest that turbulent flow might be occurred in available range of measurement system. In case of turbulent flow, estimated permeability and fracture aperture from test data tend to be low. Therefore we should achieve laminar flow. This study was used the high viscosity liquid instead of water, and test conditions which could attain laminar flow with the rock specimen was examined. The rock specimen is granite rock, has natural Y-type fractures intersection. A solution of Methyl-cellulose is used as high viscosity liquid. Due to the high viscosity liquid, hydraulic head could be measured in the wide range, and high viscosity liquid improved the accuracy of measurement. Laminar flow could be achieved in the rock specimen by the high viscosity liquid over 0.1wt%.
Dung, N. P.; Murayama, Takashi; Otsuji, Katsuhiro*; Obata, Kazuichi; Murakami, Hiroyuki
JAERI-Tech 2001-047, 28 Pages, 2001/07
JAERI-Tech-2001-047.pdf:10.97MB
no abstracts in English
Kitano, Koji*; Fuketa, Toyoshi; Sasajima, Hideo; Uetsuka, Hiroshi
JAERI-Research 2001-011, 34 Pages, 2001/03
JAERI-Research-2001-011.pdf:2.48MB
no abstracts in English
-FeSi on Si(111) substrate studied by means of SR-XPSSaito, Takeru; Yamamoto, Hiroyuki; Haraguchi, Masaharu*; Imamura, Motoyasu*; Matsubayashi, Nobuyuki*; Tanaka, Tomoaki*; Shimada, Hiromichi*; Hojo, Kiichi
Photon Factory Activity Report 2001, (19), P. 205, 2001/00
no abstracts in English
Yamamoto, Hiroyuki; Baba, Yuji
Journal of the Korean Vacuum Society, 9(S2), p.84 - 88, 2000/11
no abstracts in English
Sakai, Takaaki; ; ;
JNC TN9400 2000-012, 43 Pages, 2000/03
JNC-TN9400-2000-012.pdf:2.12MB
Experimental validation of the design method to prevent the failure of a thermometer well by the vortex-induced vibration has been performed for the effect of structure damping of a cylinder. The available experimental data in piping were very limited for the high damping region in water flow, because of the difficulty to increase the structure dumping for the one-side supported cylinder in experiments. ln this experiment, high viscosity fluid was charged into the tested cylinders to control the cylinder's damping. Resulting values of the reduced damping are 0.49, 0.96, 1.23, 1.98, 2.22 in the experiments. Reduced velocity(Vr) was increased gradually in the range of 0.7 
Vr 5(Reynolds number at Vr=1 is 810
). The displacements of the cylinder by the vortex-induced vibration were measured. As the results, Tested cylinders of reduced damping 0.49 and 0.96 showed vortex-induced vibration in flow direction at Vr 1 region. However, in case of reduced damping of 1.23, 1.98 and 2.22, the vortex-induced vibrations in flow direction were suppressed lower than the 1% displacement of the cylinder diameter. ln conclusion, it is confirmed that the suppression criteria of the "Vr 3.3 and Cn 1.2" for vortex-induced vibration in flow direction, which is used in ASME code; "Boiler and Pressure VesseI Code Sec.III Appendix N-1300" and the "FIV design guide in JNC", is reasonably applicable to the one-side supported cylinder in water flow piping.
