Development of small specimen test techniques for the IFMIF test cell

Wakai, Eiichi; Kim, B. J.; Nozawa, Takashi; Kikuchi, Takayuki; Hirano, Michiko*; Kimura, Akihiko*; Kasada, Ryuta*; Yokomine, Takehiko*; Yoshida, Takahide*; Nogami, Shuhei*; et al.

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 6 Pages, 2013/03

https://inis.iaea.org/collection/NCLCollectionStore/_Public/44/060/44060304.pdf?r=1&r=1#page=596

Use of electrical conductivity to analyze depositional environments; Example of a Holocene delta sequence on the Nobi Plain, central Japan

Niwa, Yuichi*; Sugai, Toshihiko*; Saegusa, Yoshie*; Ogami, Takashi*; Sasao, Eiji

Quaternary International, 230(1-2), p.78 - 86, 2011/01

https://doi.org/10.1016/j.quaint.2009.11.042

We assessed the usefulness of electrical conductivity (EC) of stirred Holocene deltaic sediments from three cores from the Nobi Plain, Japan, as a proxy for marine transgression and regression. Marine deposits showed high EC, terrestrial deposits low EC, and brackish deposits intermediate. Because it was positively correlated with the percentage of marine diatom species, EC in inner bay deposits primarily reflected salinity. In the YM core (the youngest of the three cores), EC of the inner bay deposits was weakly positively correlated with clay content. EC of inner bay clayey deposits was generally higher in YM than in KZN, suggesting that the lower EC in older clayey sediments results from compaction. These findings suggest that the EC values of fine sediments initially record salinity but may decrease gradually over time under the influence of compaction. Thus, to reconstruct the original salinity, the effects of compaction and of grain size distribution should be evaluated.

Development of the Kiso river delta during the last 10,000 years based on analyses of sedimentary cores and C datings

Ogami, Takashi*; Sugai, Toshihiko*; Fujiwara, Osamu*; Yamaguchi, Masaaki*; Sasao, Eiji

Chigaku Zasshi, 118(4), p.665 - 685, 2009/00

https://doi.org/10.5026/jgeography.118.665

The depositional process of the latest Pleistocene to Holocene shallow marine and fluvial sequences is investigated by using five drill cores from the Kiso river delta, central Japan. Based on facies analysis, the sediments were classified into 5 units; A: basal gravel, B: fluvial to intertidal sand and silt, C: transgressive lag deposit, prodelta mud or sandy silt, D: delta-front-slope sandy silt or sand, delta-front-platform sand, E: delta-plain to fluvial sand and silt. Detailed age-depth curves of each cores are reconstructed based on 107 AMS C ages. The curves are divided into four sections; I: mainly consists of unit B with rapid accumulation (7.3-21.4 mm/yr), II: mainly consists of unit C with moderate accumulation (2.4-2.8 mm/yr), III: mainly consists of unit D with rapid accumulation (6.7-17.8 mm/yr), IV: consists of unit D and E with moderate accumulation (1.3-3.9 mm/yr). The section boundaries of I/II and II/III reflect inundation into the bay and achievement of progradational delta-front slope, respectively. The expanding rate of the bay is 10 m/yr during 10,200-7,900 cal yrs BP. The progradation rates of the delta are 3-4 m/yr (6.500-4,100 cal yrs BP), 5 m/yr (4,100-1,300 cal yrs BP), 10 m/yr (1,300 cal yrs BP to the present). These indicate the transition from transgression to regression occurred between 7,800 to 7,300 cal yrs BP. The geological cross section along the Kiso river coupled with isochrones indicates following history. (1) 10,000-7,280 cal yrs BP (K-Ah horizon): During the expansion of the bay, onlap of unit C on unit B is visible, and unit C overlapped all the core sites. (2) 7,280 cal yrs BP to present: Isochrones younger than 6,500 cal yrs BP are similar each other and cross unit boundaries of C/D and D/E. This demonstrates units C, D and E are contemporaneous heterotopic facies formed by progradational delta.

MK-III Modification work of heat transport system in JOYO; Dismantling and sodium cleaning of secondary cooling system components

Ishii, Takayuki; Isozaki, Kazunori; Ashida, Takashi; Minakawa, Satoru; Terakado, Tsuguo; Nogami, Hiroshi*; Kakurai, Katsuhiko*; Ueda, Soji*; Kawahara, Hirotaka; Ichige, Satoshi; et al.

JNC TN9410 2002-013, 86 Pages, 2002/11

JNC-TN9410-2002-013.pdf:68.29MB

The MK-III project has been proceeding to improve the irradiation capability of the experimental fast reactor JOY0. The MK-III project has three major purposes such as increase high neutron flux, improvement of plant availability factor and upgrading in irradiation techniques. Thermal output by core transformation for high neutron flux was increased from 100MWt to 140MWt. The main components in the cooling system such as IHX(Intermediate Heat Exchanger) and DHX(Dump Heat Exchanger) were replaced in MK-III modification in order to increase heat removal capability. Heat transfer capacity of IHX was increased from 50MWt/Unit to 70MWt/Unit and that of DHX was increased from 25MWt/Unit to 35MWt/Unit. These components replacement has been safety completed from october 30, 2000 through September 21, 2001. This report summarizes the way, results and safety measures about dismantling of no sodium adhered components and such as DHX blower and sodium cleaning of sodium components such as the DHX, the pipes connected with DHX and secondary side of IHX. Dismantling and sodium cleaning of secondary cooling system components were performed safely and efficiently as almost planned. The total amount of removed sodium was about 13.5kg.

Landform development of the western part of the Nobi Plain since the late Pleistocene based on the sedimentary core analysis

Niwa, Yuichi*; Tajikara, Masayoshi; Yasue, Kenichi; Ogami, Takashi*; Sugai, Toshihiko*

no journal, , 

no abstracts in English

Late Holocene coseismic subsidence in the Nobi Plain estimated from sediment core analyses

Niwa, Yuichi*; Sugai, Toshihiko; Ogami, Takashi*; Tajikara, Masayoshi; Yasue, Kenichi; Fujiwara, Osamu*

no journal, , 

no abstracts in English

Tectonic tilting recorded in the Holocene delta sequence in the Nobi Plain, central Japan

Niwa, Yuichi*; Sugai, Toshihiko; Ogami, Takashi*; Tajikara, Masayoshi; Yasue, Kenichi

no journal, , 

no abstracts in English

A Comparison between neutron diffraction and EBSD images for a TlBr crystal

Watanabe, Kenichi*; Hitomi, Keitaro*; Nogami, Mitsuhiro*; Maeda, Shigetaka; Ito, Chikara; Tanno, Takashi; Onabe, Hideaki*

no journal, , 

TlBr is a compound semiconductor with a high atomic number, high density and a wide bandgap, and is being developed as a gamma-ray detector material that can be operated at room temperature and has high detection efficiency. There is neutron diffraction in order to establish a crystal quality evaluation method for improving the yield in device fabrication, but the facilities that can be implemented are limited to large facilities such as J-PARC. The Electron Backscatter Diffraction (EBSD) image, which is one of the electron beam diffractions, can be obtained with an electron microscope, but only the information on the crystal surface can be obtained. In this study, the crystal orientation image was acquired for the TlBr crystal by neutron Bragg dip imaging, which is one of the neutron diffractions, and EBSD. By comparing both images, the applicability to a simple EBSD crystal quality evaluation method was examined.