Status of efforts for safeguards challenges by Ningyo-toge Uranium Enrichment Facility

Ishida, Tsuyoshi; Nakashima, Shinichi; Kondo, Shinji; Hayashibara, Kenichi; Yamada, Shigeki*; Okamoto, Ryo*; Nakamura, Hironobu

Dai-44-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2023/11

no abstracts in English

Eco-friendly carboxymethyl cellulose nanofiber hydrogels prepared via freeze cross-linking and their applications

Sekine, Yurina; Nankawa, Takuya; Yunoki, Shunji*; Sugita, Tsuyoshi; Nakagawa, Hiroshi; Yamada, Teppei*

ACS Applied Polymer Materials (Internet), 2(12), p.5482 - 5491, 2020/12

https://doi.org/10.1021/acsapm.0c00831

We developed a cross-linking method using freeze concentration and used it to synthesize a new type of carboxymethyl cellulose nanofiber (CMCF) hydrogel with high compressive strength ( 80 MPa) and high compressive recoverability. The hydrogels were prepared by adding an aqueous solution of citric acid (CA) to a frozen CMCF sol and then thawing the sol. The reaction between the freeze-concentrated CMCF and CA created a rigid porous structure that reflected the ice crystal structure. Their cross-linked structure has a high stability to compressive stress. Bentonite was immobilized on a CMCF hydrogel by adding bentonite to the CMCF sol before freeze cross-linking. The CMCF-bentonite hydrogel showed high adsorptivity for chemical dyes. The physically cross-linked CMCF hydrogels are non-toxic, metal-free, and simple to prepare, and thus they may be useful as sustainable materials in various fields.

Speciation of radioactive soil particles in the Fukushima contaminated area by IP autoradiography and microanalyses

Mukai, Hiroki*; Hatta, Tamao*; Kitazawa, Hideaki*; Yamada, Hirohisa*; Yaita, Tsuyoshi; Kogure, Toshihiro*

Environmental Science & Technology, 48(22), p.13053 - 13059, 2014/12

https://doi.org/10.1021/es502849e

no abstracts in English

Annual report for research on long-term stability of geological environments in FY2007

Kusano, Tomohiro; Nohara, Tsuyoshi; Umeda, Koji; Ishimaru, Tsuneari; Hanamuro, Takahiro; Saito, Tatsuo; Yasue, Kenichi; Niwa, Masakazu; Shimada, Koji; Yamada, Kunimi; et al.

JAEA-Research 2009-022, 47 Pages, 2009/09

JAEA-Research-2009-022.pdf:48.94MB

The Japanese islands are located in the tectonically active Circum-Pacific Mobile Belt. As a result, Japan has a high frequency of earthquakes and eruptions. Special consideration is given to the long-term stability of the geological environment, taking into account volcanism, faulting, uplift, denudation, climatic change and sea-level change in Japan. Development of research/prediction technologies for geotectonic events has been carried out to evaluate the long-term stability of the geological environment in Japan. In fiscal year 2007, we carried out the following researches, to confirm existence of the phenomena that have influences on geological disposal system (e.g., active faulting, volcanism), and to develop the investigation techniques to reconstruct the history of these phenomena. For studies of faulting and seismic activity, we developed the investigation techniques to research distribution of crush zone, process of faulting, activity, and so on. For volcanological and geothermal studies, we developed a technique for detecting crustal magma and/or geothermal fluid in deep underground. For studies of uplift/denudation and climatic/sea-level changes, we extracted investigation techniques for landform developments and uplift rate with river terraces.

Experimental investigation of particle pinch associated with turbulence in LHD heliotron and JT-60U tokamak plasmas

Tanaka, Kenji*; Takenaga, Hidenobu; Muraoka, Katsunori*; Michael, C.*; Vyacheslavov, L. N.*; Yokoyama, Masayuki*; Yamada, Hiroshi*; Oyama, Naoyuki; Urano, Hajime; Kamada, Yutaka; et al.

Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 8 Pages, 2008/10

http://www-naweb.iaea.org/napc/physics/FEC/FEC2008/html/node226.htm#48899

Comparative studies were carried out in LHD heliotron and JT-60U tokamak plasmas to elucidate the most essential parameter(s) for control of density profiles in toroidal systems. A difference in the collisionality dependence was found between the two devices. In LHD, the density peaking factor decreased with decrease of the collisionality at the magnetic axis position (R) 3.6 m, while the density peaking factor gradually increased with a decreased of collisionality at R = 3.5 m. On the other hand, in JT-60U, the density peaking factor clearly increased with a decrease of the collisionality. The difference in the collisionality dependence between R = 3.5 and R = 3.6 m is likely due to the contribution of the anomalous transport. At R = 3.5 m, larger anomalous transport caused a similar collisionality dependence. Change of the fluctuation property was observed with different density profiles in the plasma core region on both devices. In JT-60U, the increase of the radial coherence was observed with higher density peaking profile suggesting enhanced diffusion and inward directed pinch. For a magnetic axis positions (R) at 3.6 m in LHD, the increase of the fluctuation power with an increase in P was observed for a hollow density profile suggesting an increase on diffusion due to anomalous processes. Change of density profiles from peaked to hollow indicates change in the convection direction. This is due to increase in neoclassical processes. The reduction of the density peaking factor with increase of P in LHD is partly due to the neoclassical effect and partly due to the anomalous effect.

Annual report for research on long-term stability of geological environment in FY2006

Nohara, Tsuyoshi; Umeda, Koji; Sasao, Eiji; Hanamuro, Takahiro; Saito, Tatsuo; Yasue, Kenichi; Niwa, Masakazu; Mashima, Hidehisa*; Shimada, Koji; Yamada, Kunimi; et al.

JAEA-Research 2008-062, 61 Pages, 2008/07

JAEA-Research-2008-062.pdf:39.02MB

The Japanese islands are located in the tectonically active Circum-Pacific Mobile Belt. As a result, Japan has a high frequency of earthquakes and eruptions. Special consideration is given to the long-term stability of the geological environment in Japan. Development of research/prediction technologies for geotectonic events has been carried out to evaluate the long-term stability of the geological environment in Japan. During fiscal year 2006, we carried out the following researches, to confirm existence of the phenomena that have influences on geological disposal system, and to develop the research techniques to reconstruct the history of these phenomena. For studies of active faulting and seismic activity, we reviewed the existing techniques to research past activities and distribution of active faults (migration, extension, development process of a deformation zone). For volcanological and geothermal studies, we extracted a technique for detecting crustal magma and/or geothermal fluid in deep underground using geophysical and geochemical data, and models assessing the likelihood of future volcanism and its influence on geological environment. For studies of uplift/denudation and climatic/sea-level change, we constructed conceptual models such as landform development model.

Development of advanced tritium breeders and neutron multipliers for DEMO solid breeder blankets

Tsuchiya, Kunihiko; Hoshino, Tsuyoshi; Kawamura, Hiroshi; Mishima, Yoshinao*; Yoshida, Naoaki*; Terai, Takayuki*; Tanaka, Satoru*; Munakata, Kenzo*; Kato, Shigeru*; Uchida, Munenori*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node294.htm#58596

no abstracts in English

Novel separation system of trivalent actinides-combined effects of substituted tris(2-pyridylmethyl)amine ligand and hydrophobic counter-anion

Ishimori, Kenichiro*; Watanabe, Masayuki; Kimura, Takaumi; Yaita, Tsuyoshi; Yamada, Takashi*; Kataoka, Yumiko*; Shinoda, Satoshi*; Tsukube, Hiroshi*

Chemistry Letters, 34(8), p.1112 - 1113, 2005/08

https://doi.org/10.1246/cl.2005.1112

Stereochemical substitution on tripod ligand significantly offered efficient separation of trivalent actinides from trivalent lanthanides. Liquid-liquid extraction using chiral tris(2-pyridylmethyl)amine ligands as an extractant exhibited high efficiency and selectivity for trivalent actinides. A combination of chiral ligand and 2-bromodecanoic acid further enhanced extraction performance for trivalent actinides.

Additional Groundwater Sampling and Analysis in the Investigation of Deep Groundwater (DH-15 Hole)

Hama, Hiroshi*; Yamada, Tsuyoshi*; Ide, Mitsuyoshi*; Takahashi, Eiichiro*; Yamamoto, Katsuya*; Nakajima, Toshihide*; Watabe, Takeo*

JNC TJ7440 2005-074, 270 Pages, 1995/05

JNC-TJ7440-2005-074.PDF:17.59MB
JNC-TJ7440-2005-074(errata).pdf:0.08MB

In 1997, DH-5 hole was drilled at P.N.C.(present J.N.C.) Toki Branch of Tono Geoscience Centr in Gifu prefecture. The borehole was drilled to a depth of 502.3 meters in Toki granite in order to investigate the deep groundwater. This report describes the investigation of the groundwater conducted at depth from 323.8 to 330.8 meters to make clear geological, hydrogeological and geochemical characteristics of study area. The investigation includes the following items;i) Sampling of the groundwaterii) Measurement of physical chemistry parameters of the groundwater in the borehole iii) Chemicaal analysis of the main composition of the groundwater during the continuous samplingiv) Chemical analysis of the groundwater It has become clear the following points;* The physical chemistry parameters of groundwater was alkalic, low deoxidize and buffer ability. There were few total ions and sulfide ions in the groundwater.* The isotopic analysis showed that the groundwater was regarded as rainwater in origin on the side of the Pacific Ocean and was relatively young with the age of a few decades.* According to the tri-linear diagram, the groundwater was classified into Ca(HCOtype. Based on hydrochemical facies, the groundwater was classified into Casup+ Naand HCOClSOin the cation and anion facies, respectively.* Nitrite oxidizing bacteria, nitrite reducing bacteria and nitrate reducing bacteria were detected in the groundwater by the bacteria analysis.

Evaluation of influence on the radiocarbon dating by the difference in chemical pretreatment protocols

Yamada, Ryuji*; Kokubu, Yoko; Wakatsuki, Tsuyoshi*; Yasue, Kenichi

no journal, , 

Mass movements and fault movements are natural phenomena to change the local topography. Reconstruction of the movement histories and evaluation of long-term stability of topographies are crucial to assess the geological environment in future. History reconstruction based on radiocabon dating of plant material recovered from sediment deposited by the past movements requires the compilation and the comparison of existing data measured by different analysts with different methods. We compared the results of radiocarbon ages measured at different laboratories with various chemical pretreatments, using plant material samples. For older samples (about 45000 BP), dispersion in ages is greater than measurement uncertainty. However the order of weighted mean ages for each sample agrees well with stratigraphic sequence at the sampling site. It is therefore thought that the influence of the systematic error due to a specific experimental conditions is small.