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Yuan, X.*; Hu, Q.*; Lin, X.*; Zhao, C.*; Wang, Q.*; Tachi, Yukio; Fukatsu, Yuta; Hamamoto, Shoichiro*; Siitari-Kauppi, M.*; Li, X.*
Journal of Hydrology, 618, p.129172_1 - 129172_15, 2023/03
Times Cited Count：2 Percentile：26.10(Engineering, Civil)Wang, Q.*; Hu, Q.*; Zhao, C.*; Yang, X.*; Zhang, T.*; Ilavsky, J.*; Kuzmenko, I.*; Ma, B.*; Tachi, Yukio
International Journal of Coal Geology, 261, p.104093_1 - 104093_15, 2022/09
Times Cited Count：10 Percentile：74.93(Energy & Fuels)
sp
Hard Rock Laboratory in SwedenTachi, Yukio; Ito, Tsuyoshi*; Gylling, B.*
Water Resources Research, 57(11), p.e2020WR029335_1 - e2020WR029335_20, 2021/11
Times Cited Count：2 Percentile：13.35(Environmental Sciences)This paper focuses on the scaling approach for sorption and diffusion parameters from laboratory to in-situ conditions using the dataset of LTDE-SD experiment performed at the sp HRL. The near-surface heterogeneities at both fracture surface and rock matrix could be evaluated by conceptual model with high porosity and diffusivity, and sorption capacity, and their gradual change at the near-surface zones. The modelling results for non-sorbing Cl-36 and weak-sorbing Na-22 could validate the model concept and the parameter estimation of porosity and diffusivity, by considering the disturbed zone of 5 mm thickness with gradual parameter changes. The De values of these cationic and anionic tracers showed typical cation excess and anion exclusion effects. The modelling results for high sorbing tracers (Cs-137, Ra-226, Ni-63 and Np-237) with different sorption mechanism could confirm the validity of the scaling approaches of Kd values as a function of particle size and their relation to the near-surface disturbances.
Kimoto, Kazushi*; Okano, Aoi*; Saito, Takayasu*; Sato, Tadanobu*; Matsui, Hiroya
Doboku Gakkai Rombunshu, A2 (Oyo Rikigaku) (Internet), 76(2), p.I_97 - I_108, 2020/00
This study investigates the propagation characteristics of surface wave traveling in a random heterogeneous medium. For this purpose, ultrasonic measurements are performed on a granite block as a typical randomly heterogeneous medium. In this measurement, a line-focus transducer is used to excite ultrasonic waves, whereas a laser Doppler vibrometer is used to pickup the ultrasonic motion on the surface of the granite block. The measured waveforms are analysed in the frequency domain to evaluate the travel-time for each measurement point based on the Fermat's principle. From the ensemble of travel-times, the probability distribution is established as a function of travel-distance. The uncertainty of the travel-time and its spatial evolution are then investigated using the standard deviation of the travel-time as a measure of the uncertainty. As a result, it was found that the uncertainty is approximately proportional to the mean travel-time divided by the square root travel-distance.
Tachi, Yukio; Ito, Tsuyoshi*; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*
Water Resources Research, 54(11), p.9287 - 9305, 2018/11
Times Cited Count：6 Percentile：24.12(Environmental Sciences)Effects of fine-scale surface alterations on radionuclide migration in fractured crystalline rocks were investigated by a comprehensive approach coupling a series of laboratory tests, microscopic observations and modelling, using a single fractured granodiorite sample from the Grimsel Test Site, Switzerland. Laboratory tests including through-diffusion, batch sorption and flow-through tests using five tracers indicated that tracer retention was consistently in the sequence of HDO, Se, Cs, Ni, Eu, and as well as showing the existence of a diffusion-resistance layer near the fracture surface, cation excess and anion exclusion effects for diffusion. Microscale heterogeneities in structural properties around the fracture were clarified quantitatively by coupling X-ray CT and EPMA. A three layer model including weathered vermiculite, foliated mica and undisturbed matrix layers, and their properties such as porosity, sorption and diffusion parameters, could provide a reasonable interpretation for breakthrough curves and concentration distributions near fracture surface of all tracers, measured in flow-through tests.
Kamemura, Katsumi*; Aoyagi, Kazuhei; Nago, Makito*; Sugawara, Kentaro*
Dai-45-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.43 - 48, 2018/01
In situ stress state is very important for the design of deep underground facility of high-level radioactive waste disposal repository. This study establishes a practical and effective method for estimating in situ stress state based on the measured convergence and detailed geological observations during gallery excavation. The convergence was measured in various directions of the loop gallery at 350m depth of the Horonobe URL; this allows determination of the stress state corresponding to the rock mass behavior in 120m 
200m area. In situ stress state estimated by the back analysis considering existing faults and fractures showed a good agreement with that of estimated from hydraulic fracturing method.
Nojiri, Naoki; Fujimoto, Nozomu; Mori, Tomoaki; Obata, Hiroyuki*
JAERI-Data/Code 2004-012, 65 Pages, 2004/10
JAERI-Data-Code-2004-012.pdf:7.77MB
DELIGHT code is a fuel cell burnup analysis code which can produce the group constants necessary for High Temperature Gas-cooled Reactors (HTGR) core analyses. Collision probability method is used to the lattice calculation. The lattice calculation model is a cylinder type fuel or a ball type fuel of the HTGR. This code characterizes the burnup calculation considering the double heterogeneity caused by coated fuel particles of the HTGR fuel. DELIGHT code has updated its nuclear data library to the latest JENDL-3.3 data, and included new burnup chain models in order to calculate high burnup HTGR cores. The material regions of the periphery burnable poisons (BPs) were divided into details in order to improve calculation accuracy of the BP lattice calculation. This report presents the revised points of the DELIGHT-8 and can be used as user's manual.
Mori, Takamasa; Okumura, Keisuke; Nagaya, Yasunobu; Ando, Hiroei
Transactions of the American Nuclear Society, 83, p.283 - 284, 2000/00
no abstracts in English
Nojiri, Naoki; Nakano, Masaaki; Ando, Hiroei; Fujimoto, Nozomu; Takeuchi, Mitsuo; Fujisaki, Shingo; Yamashita, Kiyonobu
JAERI-Tech 98-032, 59 Pages, 1998/08
no abstracts in English
C at FCA, 4; Investigation on calculation model for the Doppler effect measurement with a heated foil using MVP codeAndo, Masaki; Okajima, Shigeaki
JAERI-Research 97-014, 22 Pages, 1997/03
JAERI-Research-97-014.pdf:0.77MB
no abstracts in English
; Nomura, Yasushi
Nihon Genshiryoku Gakkai-Shi, 39(10), p.832 - 841, 1997/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)no abstracts in English
Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; ; ; Kosako, Kazuaki*; Maekawa, Hiroshi; Nakagawa, Masayuki; Mori, Takamasa; Nakamura, Tomoo; et al.
Fusion Technology, 28(1), p.216 - 235, 1995/08
no abstracts in English
Konno, Chikara; Maekawa, Fujio; ; Kosako, Kazuaki*; Ikeda, Yujiro; Oyama, Yukio; Maekawa, Hiroshi
JAERI-Tech 94-019, 43 Pages, 1994/10
no abstracts in English
Murata, Isao; Yamashita, Kiyonobu; Maruyama, So; Shindo, Ryuichi; Fujimoto, Nozomu; Sudo, Yukio; Nakata, Tetsuo*
Journal of Nuclear Science and Technology, 31(1), p.62 - 72, 1994/01
Times Cited Count：3 Percentile：35.66(Nuclear Science & Technology)no abstracts in English
Nakagawa, Masayuki; Kosako, Kazuaki*; Mori, Takamasa; Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Yamaguchi, Seiya*; Tsuda, Koichi*; Maekawa, Hiroshi; ; et al.
JAERI-M 92-183, 106 Pages, 1992/12
no abstracts in English
Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Yamaguchi, Seiya*; Tsuda, Koichi*; Maekawa, Hiroshi; ; Kosako, Kazuaki*; Nakagawa, Masayuki; Mori, Takamasa; et al.
JAERI-M 92-182, 151 Pages, 1992/12
no abstracts in English
fuel grain size on reactivity; Continuous energy Monte Carlo calculationsSakurai, Y.*; Okuno, Hiroshi; Naito, Yoshitaka
JAERI-M 91-137, 35 Pages, 1991/09
no abstracts in English
Oyama, Yukio; ; ; Konno, Chikara; Ikeda, Yujiro; Maekawa, Hiroshi; Nakamura, Tomoo; K.Porges*; E.Bennett*
Fusion Technology, 19(3), p.1955 - 1960, 1991/05
no abstracts in English
Murata, Isao; Yamashita, Kiyonobu; Maruyama, So; Shindo, Ryuichi; Fujimoto, Nozomu; Sudo, Yukio; Nakata, Tetsuo*
Proc. of the 1st JSME/ASME Joint Int. Conf. on Nuclear Engineering,Vol. 1, p.413 - 418, 1991/00
no abstracts in English
Shindo, Ryuichi; Yamashita, Kiyonobu; Murata, Isao
JAERI-M 90-048, 225 Pages, 1990/03
no abstracts in English
