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MoO
Nagai, Takayuki; Sato, Nobuaki*; Kitawaki, Shinichi; Uehara, Akihiro*; Fujii, Toshiyuki*; Yamana, Hajimu*; Myochin, Munetaka
Journal of Nuclear Materials, 433(1-3), p.397 - 403, 2013/02
Times Cited Count：10 Percentile：61.16(Materials Science, Multidisciplinary)In order to examine easily synthetic conditions of uranyl molybdate, UOMoO, used for the reprocessing process study of spent nuclear oxide fuels in alkaline molybdate melts, the uranium molybdate compounds were produced from U
O
powder and anhydrous MoO reagent. The results of having investigated them in solid state by using X-ray diffractometry and Raman spectrometry, it was confirmed that UOMoO could be synthesized by heating mixed powder of UO and MoO with stoichiometric mole ratio at 770
C for 4 h under air atmosphere. Moreover, adding this UOMoO into LiMoO-NaMoO eutectic melt, most of the dissolved uranium species in the melt were observed as hexa-valent uranyl ions by absorption spectrophotometry.
Uehara, Shinichi*; Kobayashi, Akira*; Chijimatsu, Masakazu*; Onishi, Yuzo*; Fujita, Tomoo; Rejeb, A.*
Proceedings of 3rd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2008), p.419 - 425, 2008/06
Uehara, Shinichi*; Kobayashi, Akira*; Chijimatsu, Masakazu*; Onishi, Yuzo*; Fujita, Tomoo
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.738 - 743, 2006/05
This paper reports the results of calculations about coupled hydro-mechanical process in the domain around excavations at clay rock site at Tournemire, France. We operated the numerical modelling by using a Finite Element Method code named THAMES, on the assumption that swelling pressure is parallel to saturation ratio. The results of modelling indicated that saturation ratio changes seasonally at the domain within several tens cm from tunnel wall. This extension is similar to that of damage zone observed in the tunnel at Tournemire site in 1881, which supports the idea that the saturation-desaturation cycles has decreased the rock strength and caused damage zone extension. The modelling results also suggested that the consideration of swelling pressure could affect evolution of stress state abruptly.
Nishiyama, Satoshi*; Uehara, Shinichi*; Yano, Takao*; Saito, Ryuhei*; Uchida, Masahiro; Sawada, Atsushi; Takebe, Atsuji
JNC TY8400 2005-007, 70 Pages, 2005/03
JNC-TY8400-2005-007.pdf:2.24MB
None
Tsuzuki, Kazuhiro; Kimura, Haruyuki; Kawashima, Hisato; Sato, Masayasu; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Hoshino, Katsumichi; Bakhtiari, M.; Kasai, Satoshi; et al.
Nuclear Fusion, 43(10), p.1288 - 1293, 2003/10
Times Cited Count：39 Percentile：74.23(Physics, Fluids & Plasmas)no abstracts in English
; Uehara, Shinichi*; *; *
American Geophysical Union 2002 Fall Meeting, p.F1371 - F1372, 2002/12
The effect of micro-cracks on the transport properties of granite is studied using laser scanning microscope. 3D images of pore structure show the influence on the porosity and permeability. Anisotropy of micro-cracks are observed on two different directions in respect to the main structure. Results on permeability show a decreases by a factor of one to two order of magnitude in the direction parallel to the fault zone. In the conference will be discussed the implications of anisotropy of micro-cracks on the transport properties in crystalline rocks.
Uehara, Kazuya; Ikeda, Yoshitaka; Saigusa, Mikio; Sakamoto, Keishi; Fujii, Tsuneyuki; Maebara, Sunao; Tsuneoka, Masaki; Seki, Masami; Moriyama, Shinichi; Kobayashi, Noriyuki*; et al.
Fusion Engineering and Design, 19(1), p.29 - 40, 1992/07
Times Cited Count：1 Percentile：17.26(Nuclear Science & Technology)no abstracts in English
Uehara, Kazuya; Ikeda, Yoshitaka; Saigusa, Mikio; Sakamoto, Keishi; Fujii, Tsuneyuki; Ushigusa, Kenkichi; Maebara, Sunao; Tsuneoka, Masaki; Seki, Masami; Moriyama, Shinichi; et al.
JAERI-M 87-211, 20 Pages, 1988/01
no abstracts in English
Uehara, Shinichi*; Shimamoto, Toshihiko*; Kurikami, Hiroshi; Funaki, Hironori; Onishi, Yuzo*
no journal, ,
no abstracts in English
Uehara, Shinichi*; Shimamoto, Toshihiko*; Kurikami, Hiroshi; Niizato, Tadafumi; Funaki, Hironori; Onishi, Yuzo*
no journal, ,
no abstracts in English
Uehara, Shinichi*; Shimamoto, Toshihiko*; Kurikami, Hiroshi; Niizato, Tadafumi; Funaki, Hironori; Onishi, Yuzo*
no journal, ,
We performed permeability and porosity measurements by laboratory test under high pressure of Neogene and Quaternary sedimentary rock specimens from Horonobe area, northern Hokkaido island, Japan, and investigated the dependencies of these hydraulic properties on confining pressure and stress path. We then tried to evaluate permeability and porosity distribution as a function of the depth at this site from the measurement results and geological setting. The results indicated that the slope of permeability distribution is simulated reasonably well, which supports the applicability of this method of estimating underground hydraulic properties, but we can see some discrepancies in the value itself, which could be because of the effects of structures larger than specimen scale such as faults or fractures.
Okazaki, Keishi*; Uehara, Shinichi*; Shimamoto, Toshihiko*; Funaki, Hironori; Kurikami, Hiroshi; Niizato, Tadafumi; Onishi, Yuzo*
no journal, ,
We have conducted detailed permeability k and porosity n measurements using fresh surface samples and drill cores of the three Neogene sedimentary formations in Horonobe area. Main results are outlined as follows. (1) k and n decrease from upper to lower horizons due to compaction and cementation and with increasing effective pressure Pe. Pressure cycling tests provide basic data for estimating k and n structures of the host rock. (2) Measurements for two specimens cored next to each other under the same Pe exhibit relationship showing an increase in k with increasing n that can be fit with Kozeny-Carman relationship. (3) n plotted against logarithm of Pe shows a clear knee point, similar to compaction curves for soils. This knee point is several times as large as the maximum Pe estimated from stratigraphy and from opal A to CT transition, so that the knee cannot be correlated with the maximum burial depth of the sedimentary rocks.
Uehara, Shinichi*; Shimamoto, Toshihiko*; Funaki, Hironori; Kurikami, Hiroshi; Niizato, Tadafumi; Onishi, Yuzo*
no journal, ,
Estimation of deep underground permeability k structures is extremely difficult because transport properties of rocks are affected dramatically with fractures and fault zones and yet we do not know how much rocks are fractured and faulted at depths for a given region. We address this issue in the underground testing site in Horonobe area, where JAEA has been conducting a large-scale underground testing for sedimentary rocks. The Neogene sedimentary rocks of Horonobe area consist of Yuchi, Koetoi and Wakkanai Formations in the descending order. Hydraulic conductivity of Wakkanai Formation from in-situ measurements are compared with gas permeability as measured with a flow method for intact specimens, for fractured specimens and for breccia zones of Wakkanai Formation. In-situ data for hydraulic conductivity of lower part of Koetoi Formation is very close to that estimated from gas permeability of intact specimen, far smaller to those for brecciated samples.
Uehara, Shinichi*; Shimamoto, Toshihiko*; Funaki, Hironori; Niizato, Tadafumi; Kurikami, Hiroshi; Onishi, Yuzo*; Matsumoto, Takuma*
no journal, ,
Determination of underground transport properties is needed in modeling underground fluid flow, which is critically important in many problems such as fluid circulation, waste isolation, and carbon dioxide sequestration. Estimation of deep underground permeability structures is extremely difficult because transport properties of rocks are affected dramatically with fractures and fault zones and yet we do not know how to evaluate the effects of these structures on hydraulic properties distribution in depth. In-situ tests cannot provides transport properties at depths deeper than drill holes, whereas laboratory measurements can be done easily under conditions even deeper than 10 km as long as samples are available. Their applicability, however, to estimate real underground hydraulic structures is uncertain. Therefore, one should seek for a way of using laboratory and in-situ data complementary.
Uehara, Kazuya; Seki, Masami; Moriyama, Shinichi; Oyama, Naoyuki; Isayama, Akihiko; Kubo, Hirotaka
no journal, ,
In the lower-hybrid current drive experiment for aiming the stationary operation in tokamaks another improved confinement mode to be suppressed the anomalous transport were observed in JT-60, TRIUM-1M and so on. In JT-60, the lower-hybrid current drive experiment by injecting two waves having different frequency the improved confinement like the H mode was found with extremely lower threshold power and in the JT-60U the more efficient electron heating in the core plasma region was found at the negative shear current profile with extremely lower injected power. Considering the physical mechanism of these improved confinement modes of the lower-hybrid current drive experiment some simple calculations are performed to be compared for the experimental results.
Okazaki, Keishi*; Shimamoto, Toshihiko*; Uehara, Shinichi*; Niizato, Tadafumi
no journal, ,
Permeability and porosity are essential physical properties for analyzing of underground fluid flow. We have examined the effect of deformation on permeability and porosity of the Neogene sedimentary rocks (Yuchi, Koetoi, and Wakkanai Formations in the descending order) by laboratory experiments. Wakkanai Formation can be fluid conduit due to deformation, whereas Yuchi and Koetoi Formations do not necessarily become fluid-flow passes even with deformation. The deepest part of Koetoi Formation seems to have the highest seal capacity among the three formations.
Uehara, Shinichi*; Matsumoto, Takuma*; Shimamoto, Toshihiko*; Okazaki, Keishi*; Niizato, Tadafumi
no journal, ,
no abstracts in English
