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Journal Articles

Structure of an aqueous RbCl solution in the gigapascal pressure range by neutron diffraction combined with empirical potential structure refinement modeling

Zhang, W. Q.*; Yamaguchi, Toshio*; Fang, C. H.*; Yoshida, Koji*; Zhou, Y. Q.*; Zhu, F. Y.*; Machida, Shinichi*; Hattori, Takanori; Li, W.*

Journal of Molecular Liquids, 348, p.118080_1 - 118080_11, 2022/02

 Times Cited Count:0 Percentile:0.01(Chemistry, Physical)

The ion hydration and association and hydrogen-bonded water structure in an aqueous 3 mol/kg RbCl solution were investigated at 298 K/0.1 MPa, 298 K/1 GPa, 523 K/1 GPa, and 523 K/4 GPa by neutron diffraction combined with EPSR methods. The second hydration layer of Rb$$^+$$ and Cl$$^-$$ becomes evident under elevated pressure and temperature conditions. The average oxygen coordination number of Rb$$^+$$ (Cl$$^-$$) in the first hydration layer increases from 6.3 (5.9) ambient pressure to 8.9 (9.1) at 4 GPa, while decreasing coordination distance from 0.290 nm (0.322 nm) to 0.288 nm (0.314 nm). The orientation of the water dipole in the first solvation shell of Rb$$^+$$ and a central water molecule is sensitive to pressure, but that in the first solvation shell of Cl$$^-$$ does not change very much. The number of contact-ion pairs Rb$$^+$$-Cl$$^-$$ decreases with elevated temperature and increases with elevated pressure. Water molecules are closely packed, and the tetrahedral hydrogen-bonded network of water molecules no longer exists in extreme conditions.

Journal Articles

Ion hydration and association in an aqueous calcium chloride solution in the GPa range

Yamaguchi, Toshio*; Nishino, Masaaki*; Yoshida, Koji*; Takumi, Masaharu*; Nagata, Kiyofumi*; Hattori, Takanori

European Journal of Inorganic Chemistry, 2019(8), p.1170 - 1177, 2019/02

 Times Cited Count:10 Percentile:71.49(Chemistry, Inorganic & Nuclear)

Neutron diffraction measurements of an aqueous 2 mol dm$$^{-3}$$ CaCl$$_2$$ solutions in D$$_{2}$$O have been made at 1 GPa, 298 K as well as 0.1 MPa, 298 K. The experimental structure factors are subjected to Empirical Potential Structure Refinement (EPSR) modeling to reveal the ion hydration and association and solvent water at the atomic level. About seven water molecules surround Ca$$^{2+}$$ at the Ca-O and Ca-D distances of 2.44 ${AA}$ and 3.70 ${AA}$, respectively, at both pressures, suggesting no significant pressure effect on the cation hydration. On the other hand, the Cl$$^{-}$$ ion shows a drastic change in water oxygen coordination from 7 at 0.1 MPa to 14 at 1 GPa, accompanied by shortening of Cl-O distance from 3.18 ${AA}$ to 3.15 ${AA}$. However, the number of water hydrogen atoms around Cl$$^{-}$$ does not change significantly as 6.0 $$sim$$ 6.7 with shortening Cl-D distance from 2.22 to 2.18 ${AA}$ on compression. The pressure effect on the solvent water structure is also drastic as an increase in water oxygen atoms of 4.7 at the O-O distance of 2.79 ${AA}$ at 0.1 MPa to 10.3 at 2.85 ${AA}$ at 1 GPa. The number of water hydrogen atoms, however, does not change as 1.2 at the O-D distance of 1.74 ${AA}$ for both pressures, demonstrating the presence of the O$$cdots$$D hydrogen bonds which are significantly bent at 1 GPa at 298 K. This change of hydrogen bonds in water with pressure probably causes the drastic increase in water oxygen atoms around Cl$$^{-}$$.

Journal Articles

Thermal behavior, structure, dynamic properties of aqueous glycine solutions confined in mesoporous silica MCM-41 investigated by X-ray diffraction and quasi-elastic neutron scattering

Yoshida, Koji*; Inoue, Takuya*; Torigoe, Motokatsu*; Yamada, Takeshi*; Shibata, Kaoru; Yamaguchi, Toshio*

Journal of Chemical Physics, 149(12), p.124502_1 - 124502_10, 2018/09

 Times Cited Count:3 Percentile:17.63(Chemistry, Physical)

Differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering (QENS) measurements of aqueous glycine solutions confined in mesoporous silica (MCM-41) were performed at different glycine concentrations, pH, and loading ratio (= mass of glycine solution / mass of dry MCM-41) in the temperature range from 305 to 180 K to discuss the confinement effect on the thermal behavior, the structure, and the dynamic properties of the solutions.

Journal Articles

Establishment of a Laboratory for $$gamma$$-ray Spectrometry of Environmental Samples Collected in Fukushima

Saegusa, Jun; Yoda, Tomoyuki; Maeda, Satoshi; Okazaki, Tsutomu; Otani, Shuichi; Yamaguchi, Toshio; Kurita, Yoshiyuki; Hasumi, Atsushi; Yonezawa, Chushiro*; Takeishi, Minoru

Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1078 - 1085, 2017/11

After the nuclear accident at the Fukushima Daiichi Nuclear Power Plant in March 2011, the Japan Atomic Energy Agency has newly set up a laboratory for radioactivity analysis in Fukushima. At the laboratory, radioactivity concentrations of environmental samples such as soil, water, dust filter, plant, etc., approximately 1,000 samples in a month, are measured with high-resolution $$gamma$$-ray spectrometry systems. The systems employ n-type HPGe detectors from Ortec. Since September 2012, characterization and upgrade of the systems have been performed aimed at enhancing reliability of analysis and convenience of customers. Resolving both systematic and technical issues, the laboratory has been accredited the ISO/IEC 17025 standard as a testing laboratory for radioactivity analysis.

Journal Articles

Science from the initial operation of HRC

Ito, Shinichi*; Yokoo, Tetsuya*; Masuda, Takatsugu*; Yoshizawa, Hideki*; Soda, Minoru*; Ikeda, Yoichi*; Ibuka, Soshi*; Kawana, Daichi*; Sato, Taku*; Nambu, Yusuke*; et al.

JPS Conference Proceedings (Internet), 8, p.034001_1 - 034001_6, 2015/09

Journal Articles

Structure of water from ambient to 4 GPa revealed by energy-dispersive X-ray diffraction combined with empirical potential structure refinement modeling

Yamaguchi, Toshio*; Fujimura, Koji*; Uchi, Kazuya*; Yoshida, Koji*; Katayama, Yoshinori

Journal of Molecular Liquids, 176, p.44 - 51, 2012/12

 Times Cited Count:15 Percentile:52.05(Chemistry, Physical)

X-ray diffraction measurements in an energy-dispersive mode have been made on water under various thermodynamic conditions of 298 K/30 MPa, 473 K/30 MPa and 573 K/30 MPa on a laboratory X-ray diffractometer. All the X-ray structure factors as well as those of water already measured at 298 K/1 GPa, 473 K/0.35 GPa and 486 K/4 GPa by using synchrotron X-ray radiation were subjected to empirical potential structure refinement (EPSR) modeling to reveal the detailed hydrogen bonding features in terms of partial pair correlation function, coordination number and three-dimensional spatial density function as a function of temperature and pressure. It has been shown to what extent the tetrahedral hydrogen-bonded network of water is perturbed by pressure and temperature.

Journal Articles

Development of laser cutting technology for reactor decommissioning process

Kobayashi, Kojiro*; Ida, Toshio*; Yamaguchi, Takeshi*; Daido, Hiroyuki; Muramatsu, Toshiharu; Sano, Kazuya; Tsuboi, Akihiko*; Shamoto, Hideyasu*; Ikeda, Takeshi*

Reza Kako Gakkai-Shi, 19(1), p.63 - 67, 2012/03

Laser cutting method, is that the metal melted by laser power is removed by assist gas, has some advantages which are high speed cutting and narrow line-width cutting for the thin metal. We has conducted the joint research with the relevant organizations on the R&D of the laser cutting technology for cutting stainless and carbon steel of over the 150 mm thickness which is maximum thickness of core structure in Fugen. We report the R&D plan and the current status of the laser cutting test.

Journal Articles

Laser cutting technologies under water for the nuclear reacter dismantlement

Kobayashi, Kojiro*; Ida, Toshio*; Yamaguchi, Takeshi*; Daido, Hiroyuki; Muramatsu, Toshiharu; Sano, Kazuya; Tsuboi, Akihiko*; Shamoto, Hideyasu*; Ikeda, Takeshi*

Yosetsu Gijutsu, 59(7), p.64 - 69, 2011/07

no abstracts in English

Journal Articles

Highly efficient homogeneous liquid-liquid extraction of lanthanoid ions in a strong acidic solution

Fuchimukai, Junichi*; Yamaguchi, Hitoshi*; Meguro, Yoshihiro; Kubota, Toshio*; Igarashi, Shukuro*

Solvent Extraction Research and Development, Japan, 13, p.139 - 146, 2006/00

no abstracts in English

JAEA Reports

Proceedings of Second JAERI-JNC Joint Conference on Nuclear Safety Research; February 6, 2004, Tokyo

Sugimoto, Jun*; Anoda, Yoshinari*; Araya, Fumimasa*; Yamaguchi, Toshio*; Sato, Yoshinori;

JNC TN1200 2004-002, 100 Pages, 2004/07

JNC-TN1200-2004-002.pdf:5.41MB

The second JAERI-JNC Joint Conference on Nuclear Safety Research was held on February 6, 2004 in Tokyo for those who are relevant to nuclear industries and regulatory organizations, and general public. The nuclear safety research has been conducted in both institutes according to the Five-Year Program for Nuclear Safety Research established periodically by the Nuclear Safety Commission (NSC) and needs from the regulatory organizations. The objectives of the conference are to present its recent results and to collect views and opinions from the participants for its future program through the discussion after each presentation and panel discussion on how to conduct efficiently the nuclear safety research in the New Organization. A total of 259 people participated in the conference mainly from the nuclear industries and regulatory organizations and the number was much larger than that in the last conference of 188.The conference consisted of presentations on the safety research results, a special lecture and a panel discussion. First, the overview of safety research results was presented from each institute. Then, the results in the field of nuclear installations,environmental adioactivity and radioactive waste were presented from each institute. Then, Dr. Higashi, the Nuclear Safety Commissioner, made a special lecture on the radiation protection from the high-level radioactive waste disposal. Finally, a panel discussion was conducted with the title of "how to conduct efficiently the nuclear safety research in the New Organization" chaired by Prof. Kimura, the chairperson of Standing Committee on Nuclear Safety Research under the NSC. The panelists from the regulatory organizations, nuclear industry, JAERI and JNC discussed the subject together with the participants on the floor.The panelists not from JAERI and JNC expressed their views and opinions on how to conduct efficiently the nuclear safety research in the New Organization that were valuable inputs for

JAEA Reports

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

JAEA Reports

Measurement of $$^{237}$$Np Fission Cross Section at YAYOI

Oki, Shigeo; Takashima, Hideki; Wakabayashi, Toshio; Yamaguchi, Kenji*; Yamawaki, Michio*

JNC TY9400 2004-005, 36 Pages, 2004/05

JNC-TY9400-2004-005.pdf:1.01MB

In the framework of the study on transmutation of minor actinide (MA) nuclides with fast reactors, the fission cross section ratio of 237Np relative to 235U has been measured by using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. The compact BTB fission chamber was prepared for the measurements in the experimental holes called Glory hole and Grazing hole passing though the core center and the side blanket of YAYOI, respectively. Dependence of fission cross section ratios on neutron spectrum was investigated by changing the measurement position in these experimental holes.The measured values of fission cross section ratios were compared with those calculated with the following nuclear data libraries: JENDL-3.2, ENDF/B-VI, JEF-2.2, and JENDL-2. It was found that the calculated values in the center of the core systematically overestimated the measurements by about 30%. Dispersion of the calculated values among the nuclear data libraries was smaller than the above difference from the measured value. We also see the dependence of C/E value on the measurement position. It is hardly said that uncertainty of nuclear data brings about the above overestimation of 30%.The present result remained some issues in terms of the measurement accuracy. If we can get rid of those causes, for example, by means of the unfolding technique on pulse height distribution, the result could be utilized as expletive information in nuclear data validation not only for 237Np, but also for 235U and 238U which characterize the neutron spectrum.

JAEA Reports

Measurement of $$^{241}$$Am, $$^{243}$$Am Fission Cross Sections at YAYOI

Okawachi, Yasushi; Oki, Shigeo; Wakabayashi, Toshio; Yamaguchi, Kenji*; Yamawaki, Michio*

JNC TY9400 2004-004, 37 Pages, 2004/05

JNC-TY9400-2004-004.pdf:1.03MB

In the framework of the study on transmutation of minor actinide (MA) nuclides with fast reactors, the fission cross section ratios of MA (241Am, 243Am) relative to 235U have been measured by using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. The compact BTB fission chamber was prepared for the measurements in the main experimental hole (Glory hole) passing though the core of YAYOI. Dependence of fission cross section ratios on neutron spectrum was investigated by changing the measurement position in Glory hole from core center to depleted uranium blanket.The measured values of fission cross section ratios were compared with those calculated with the following nuclear data libraries: JENDL-3.2, ENDF/B-VI, and JEF-2.2. It was found that the calculated values for both 241Am and 243Am in the center of the core systematically underestimated the measurements by 10 to 20%. Dispersion of the calculated values among the nuclear data libraries was smaller than the above difference from the measured value. We also see the dependence of C/E value on the measurement position.The present result remained some issues in terms of the measurement accuracy. If we can get rid of those causes, for example, by means of the unfolding technique on pulse height distribution, the result could be utilized as expletive information in nuclear data validation not only for 241Am and 243Am but also for 235U and 238U which characterize the neutron spectrum.

JAEA Reports

A Development of a database system for the released radioactive gases and liquid from the nuclear facilities

Kikuchi, Masamitsu; Taki, Mitsumasa; Kume, Etsuo; Kobayashi, Hideo*; Yamada, Toshio*; Yamaguchi, Takenori

JAERI-Data/Code 2004-006, 146 Pages, 2004/03

JAERI-Data-Code-2004-006.pdf:6.87MB

The nuclear facilities, which are required to control the released radioactive gases and liquid, exist in Tokai research establishment as much as 40. These radioactive controls are carried out complying with the statutes in each facility. The released radioactivity data of each facility must be reported to MEXT and Ibaraki Prefecture from Tokai Research Establishment. This system is developed to make the database gathering the radioactivity data of each facilities for unitary control as Tokai Research Establishment and contribute to make the reports to MEXT and Ibaraki Prefecture.

JAEA Reports

None

Niwa, Hajime; Kawata, Norio; Ieda, Yoshiaki; Sato, Ikken; Ohno, Shuji; Uto, Nariaki; Miyahara, Shinya; Kondo, Satoru; Kamide, Hideki; Yamaguchi, Akira; et al.

PNC TN9410 94-154, 317 Pages, 1995/03

PNC-TN9410-94-154.pdf:13.66MB

None

Oral presentation

An Experimental study of host rock alteration due to hyperalkaline pore water

Yamaguchi, Kohei; Oda, Chie; Nakazawa, Toshiyuki*; Yamada, Norikazu*; Takase, Toshio*

no journal, , 

In this research, the batch immersion experiment and the flow-through column experiment of granite and the artificial highperalkaline pore water were conducted, and the main geochemistry reaction was examined. A change with the lapse of time of the saturation index was calculated by the chemical equilibrium computation based on the batch immersion experiment result. The secondary mineral with the possibility of precipitation in the liquid phase based on the calculation result was extracted, and the combination was examined. In addition, the combination of these secondary minerals was applied to the flow-through column experiment result, and the liquid phase composition after the flow-through and the secondary mineral's spatial distribution were compared with geochemistry calculation (PHREEQC) result. As a result, it has been understood to have to understand the main geochemistry reaction paying attention at the precipitation rate of the secondary mineral in the future.

Oral presentation

An Experimental study and modeling of host rock alteration due to hyperalkaline pore water

Yamaguchi, Kohei; Oda, Chie; Nakazawa, Toshiyuki*; Yamada, Norikazu*; Takase, Toshio*

no journal, , 

High alkaline pore water runs out from a large amount of cementitious material used for the TRU waste disposal to the host rock, and there is a possibility that the migration characteristic of the nuclide. Here, the applicability of a chemical model in the environment with water flow was evaluated by the viewpoint of the solution composition and the precipitation composition by conducting the experiment that passed high alkaline solution to the column. As a result, a change with the lapse of time of the concentration was able to be reproduced almost for the solution composition. Moreover, the precipitation of Al was not able to be reproduced though Ca and Si were able to be wide in the column. The thermodynamics data of the secondary mineral including Al, the maintenance of the precipitation rate, and the applicability examination to the experiment result etc. are profitable as future tasks.

Oral presentation

Scenario development for mineral alternations in granite by high pH solution

Shimoda, Satoko*; Saito, Hironori*; Takase, Toshio*; Yamaguchi, Kohei; Oda, Chie; Honda, Akira

no journal, , 

The unstable primary mineral is dissolved and the precipitation of a steadier secondary mineral happens thermodynamically when a high alkaline groundwater of the cement system material origin is infiltrated from the radioactive waste geological disposal facilities to a peripheral bedrock. Therefore, the pore structure of the hostrock changes by the precipitation and dissolution, and the material transportation characteristic of the bedrock changes. It is necessary to decide the chemical reaction scheme for the analysis. However, the combination of the secondary minerals exists innumerably. Therefore, granite was assumed to be an example by summarizing the chemical reaction scheme in the mineral alteration scenario, and the mineral alteration scenario concerning the reaction with a high pH groundwater was presented. It dealt with the uncertainty concerning the mineral alteration by preparing two or more scenarios with a different alteration route.

Oral presentation

Outline of Sasakino Analytical Laboratory, Fukushima Environmental Safety Center of JAEA

Saegusa, Jun; Yanagisawa, Kayo; Yamaguchi, Toshio; Manabe, Sachi; Yoda, Tomoyuki; Maeda, Satoshi; Utsumi, Azusa; Shibamichi, Masaru; Ejiri, Akira; Kurita, Yoshiyuki; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of plasma heating technology for simulation of LWR severe accident behavior, 3; Consideration of a wide range of oxygen mapping analysis method using the EPMA

Abe, Yuta; Nakagiri, Toshio; Sato, Ikken; Nakano, Natsuko*; Tanaka, Hiroshi*; Yamaguchi, Hidenobu*

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)