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Journal Articles

Evaluation of the characteristics of metal nitrate aqueous solutions by microwave heating and the morphologies of synthesized metal oxide powders

Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Fukasawa, Tomonori*; Fukui, Kunihiro*

Funtai Kogakkai-Shi, 57(9), p.485 - 494, 2020/09

In the spent fuel reprocessing process, a mixed solution of uranyl nitrate and plutonium nitrate is converted into mixed oxide powder by the microwave heating. To evaluate the applicability to the industrial-scale and acquire the characteristics data of the microwave heating denitration of various metal nitrate aqueous solutions based on the knowledge studied in the development of laboratory-scale basic experiments, the microwave heating characteristics and metal oxide powder properties were investigated using cerium nitrate, cobalt nitrate and copper nitrate aqueous solutions. The progress rate of the denitration reaction was depended on the position, and the denitration reaction proceeded faster at the periphery than at the center. The morphologies of the synthesized products were porous and hard dry solid with cerium nitrate aqueous solution, foamed dry solid with cobalt nitrate aqueous solution, and powdery particles with copper nitrate aqueous solution. The denitration ratio and average particle size of the synthesized products increased in the order of the cerium nitrate aqueous solution, the cobalt nitrate aqueous solution, and the copper nitrate aqueous solution. The numerical simulations revealed that the periphery of the bottom surface of the metal nitrate aqueous solution was heated by microwaves. This results consistent with the experimental results in which the denitration reaction started from the periphery of the metal nitrate aqueous solution.

Journal Articles

$$gamma$$-radiation and H$$_{2}$$O$$_{2}$$ induced oxidative dissolution of uranium(IV) oxide in aqueous solution containing phthalic acid

Kumagai, Yuta; Jonsson, M.*

Dalton Transactions (Internet), 49(6), p.1907 - 1914, 2020/02

 Times Cited Count:0 Percentile:100(Chemistry, Inorganic & Nuclear)

This study aims to reveal possible involvements of organic acids in the oxidative dissolution of UO$$_{2}$$. Using phthalic acid as a model compound, we have measured adsorption on UO$$_{2}$$ and investigated effects on the reaction between H$$_{2}$$O$$_{2}$$ and UO$$_{2}$$ and on oxidative dissolution induced by $$gamma$$-irradiation. Significant adsorption of phthalic acid was observed even at neutral pH. However, the reaction between H$$_{2}$$O$$_{2}$$ and UO$$_{2}$$ in phthalic acid solution induced oxidative dissolution of U(VI) similarly to aqueous bicarbonate solution. These results indicate that even though phthalic acid adsorbs on the UO$$_{2}$$ surface, it is not involved in the interfacial reaction by H$$_{2}$$O$$_{2}$$. In contrast, the dissolution of U by irradiation was inhibited in aqueous phthalic acid solution, whereas H$$_{2}$$O$$_{2}$$ generated by radiolysis was consumed by UO$$_{2}$$. The inhibition suggests that radical species derived from phthalic acid was involved in the redox reaction process of UO$$_{2}$$.

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:2 Percentile:54.11(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

Effect of chloride concentration on corrosion behavior of carbon steel under $$gamma$$-ray irradiation

Motooka, Takafumi; Ueno, Fumiyoshi

Zairyo To Kankyo, 64(6), p.220 - 223, 2015/06

Corrosion behavior of carbon steel in chloride aqueous solutions under a low dose rate was investigated by corrosion test using chloride aqueous solutions with different chloride concentration at a dose rate of 500 Gy/h. The corrosion rate of carbon steel increased by the irradiation, and the corrosion rate had the maximum value at a certain chloride concentration. The oxidants produced by radiolysis of chloride aqueous solution enhanced the corrosion of carbon steel. The main oxidants were oxygen and hydrogen peroxide, and the diffusion process of oxidants controlled the corrosion of carbon steel under irradiation. There was a positive correlation between the dependence of corrosion rate and chloride concentration and the dependence of oxidant concentration and chloride concentration.

Journal Articles

Curium(III) species and the coordination states in concentrated LiCl-aqueous solutions studied by time-resolved laser-induced fluorescence spectroscopy

Arisaka, Makoto; Kimura, Takaumi; Nagaishi, Ryuji; Yoshida, Zenko

Journal of Alloys and Compounds, 408-412, p.1307 - 1311, 2006/02

 Times Cited Count:6 Percentile:54.07(Chemistry, Physical)

no abstracts in English

Journal Articles

Yield of OH radicals in water under high-density energy deposition by heavy-ion irradiation

Taguchi, Mitsumasa; Kojima, Takuji

Radiation Research, 163(4), p.455 - 461, 2005/04

 Times Cited Count:23 Percentile:41.56(Biology)

no abstracts in English

Journal Articles

Development of light absorbance measurement system under heavy ion irradiation based on the photon-counting method

Taguchi, Mitsumasa; Kojima, Takuji

JAERI-Review 2004-025, TIARA Annual Report 2003, p.141 - 142, 2004/11

no abstracts in English

Journal Articles

${it Ab initio}$ molecular dynamics study of polarization effects on ionic hydration in aqueous AlCl$$_{3}$$ solution

Ikeda, Takashi; Hirata, Masaru; Kimura, Takaumi

Journal of Chemical Physics, 119(23), p.12386 - 12392, 2003/12

 Times Cited Count:41 Percentile:20.02(Chemistry, Physical)

The solvation shell structure and dynamics of Al$$^{3+}$$ and Cl$$^{-}$$ in an aqueous solution of 0.8 M AlCl$$_{3}$$ are studied under ambient conditions by using ${it ab initio}$ molecular dynamics method. The solvation structures obtained from our ${it ab initio}$ simulations are in good agreement with the experimental ones for both Al$$^{3+}$$ and Cl$$^{-}$$. A detailed analysis of intramolecular geometry of hydration waters and dipole moments of the ingredients shows that the polarization has substantial effects on the structures and dynamics of both the cation and anion hydration shells. Implications to the metal hydrolysis of Al$$^{3+}$$ will also be given.

Journal Articles

Differential analyses of transient species initially produced in single heavy ion track; Nuclear and specific energy dependence

Taguchi, Mitsumasa; Kojima, Takuji

JAERI-Review 2003-033, TIARA Annual Report 2002, p.141 - 142, 2003/11

no abstracts in English

Journal Articles

Decomposition of phenolic endocrine disrupting chemicals by potassium permanganate and $$gamma$$-ray irradiation

Abe, Yasuhiro*; Takigami, Machiko; Sugino, Koji*; Taguchi, Mitsumasa; Kojima, Takuji; Umemura, Tomonari*; Tsunoda, Kinichi*

Bulletin of the Chemical Society of Japan, 76(8), p.1681 - 1685, 2003/08

 Times Cited Count:5 Percentile:72.28(Chemistry, Multidisciplinary)

The decomposition of phenolic endocrine disrupting chemicals (P-EDCs), such as phenol, 4-butylphenol (BuP), and bisphenol A (BPA), in aqueous solutions by potassium permanganate (KMnO$$_{4}$$) was studied and its efficiency was compared with that of hydroxyl radicals (OH$$^{.}$$) generated by $$^{60}$$Co $$gamma$$-ray irradiation. Various organic acids and inorganic carbon were formed in the decomposition of P-EDCs due to either KMnO$$_{4}$$ or OH$$^{.}$$. They were formed via direct aromatic ring cleavage in the case of KMnO$$_{4}$$ and OH$$^{.}$$ addition-substitution reactions followed by aromatic ring cleavage in the case of OH$$^{.}$$. Comparing the decrease in the P-EDCs based on the number of electrons, the amount of KMnO$$_{4}$$ spent to completely eliminate BuP and BPA was comparable to the amount of OH$$^{.}$$. Although three times more KMnO$$_{4}$$ was needed for phenol than OH$$^{.}$$, the complete conversion of phenol into organic acids and inorganic carbon was achieved with 720$$mu$$M of electrons in both cases.

Journal Articles

Monte Carlo simulation of strand-break induction on plasmid DNA in aqueous solution by monoenergetic electrons

Watanabe, Ritsuko; Saito, Kimiaki

Radiation and Environmental Biophysics, 41(3), p.207 - 215, 2002/08

no abstracts in English

JAEA Reports

TRACY transient experiment databook, 3; Ramp feed experiment

Nakajima, Ken; Yamane, Yuichi; Ogawa, Kazuhiko; Aizawa, Eiju; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

JAERI-Data/Code 2002-007, 123 Pages, 2002/03

JAERI-Data-Code-2002-007.pdf:4.34MB

no abstracts in English

JAEA Reports

TRACY transient experiment databook, 2; Ramp withdrawal experiment

Nakajima, Ken; Yamane, Yuichi; Ogawa, Kazuhiko; Aizawa, Eiju; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

JAERI-Data/Code 2002-006, 176 Pages, 2002/03

JAERI-Data-Code-2002-006.pdf:6.33MB

no abstracts in English

JAEA Reports

TRACY transient experiment databook, 1; Pulse withdrawal experiment

Nakajima, Ken; Yamane, Yuichi; Ogawa, Kazuhiko; Aizawa, Eiju; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

JAERI-Data/Code 2002-005, 158 Pages, 2002/03

JAERI-Data-Code-2002-005.pdf:6.55MB

no abstracts in English

JAEA Reports

Water permeability test of rock specimen with natural fractures using high viscosity liquid

*;

JNC-TN8430 2001-006, 72 Pages, 2001/10

JNC-TN8430-2001-006.pdf:1.71MB

We had been conducted to study hydraulic permeability along fracture intersection by NETBLOCK system using natural rock specimen. Since the permeability of this rock specimen fracture is high, it was suggest that turbulent flow might be occurred in available range of measurement system. In case of turbulent flow, estimated permeability and fracture aperture from test data tend to be low. Therefore we should achieve laminar flow. This study was used the high viscosity liquid instead of water, and test conditions which could attain laminar flow with the rock specimen was examined. The rock specimen is granite rock, has natural Y-type fractures intersection. A solution of Methyl-cellulose is used as high viscosity liquid. Due to the high viscosity liquid, hydraulic head could be measured in the wide range, and high viscosity liquid improved the accuracy of measurement. Laminar flow could be achieved in the rock specimen by the high viscosity liquid over 0.1wt%.

JAEA Reports

Development of Thermodynamic Databases for Geochemial Calculations

Oda, Chie; Arthur, R. C.*; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu; Neyama, Atsushi*

JNC-TN8400 99-079, 287 Pages, 1999/09

JNC-TN8400-99-079.pdf:9.78MB

Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000$$^{circ}$$C. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25$$^{circ}$$C) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25$$^{circ}$$C and 1 bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100$$^{circ}$$C at 1 bar. All equilibrium constants, reaction enthalpies, and logK(T) coefficients in PHREEQE.JNC are calculated usig SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT ...

JAEA Reports

Critical configurations of basical slab cores with 10% enriched uranyl nitrate solution

; Miyoshi, Yoshinori; *; Yamane, Yuichi; Tonoike, Kotaro

JAERI-Tech 99-038, 61 Pages, 1999/04

JAERI-Tech-99-038.pdf:2.75MB

no abstracts in English

Journal Articles

Structural study of lanthanides(III) in aqueous nitrate and chloride solutions by EXAFS

Yaita, Tsuyoshi; Narita, Hirokazu*; Suzuki, Shinichi; Tachimori, Shoichi; Motohashi, Haruhiko; Shiwaku, Hideaki

Journal of Radioanalytical and Nuclear Chemistry, 239(2), p.371 - 375, 1999/00

 Times Cited Count:82 Percentile:1.78(Chemistry, Analytical)

no abstracts in English

Journal Articles

Measurement of the power profile during nuclear excursions initiated by various reactivity additions using TRACY

; Nakajima, Ken; Yanagisawa, Hiroshi; ; ; *; *; Sakuraba, Koichi; Ono, Akio

Proceedings of 6th International Conference on Nuclear Criticality Safety (ICNC '99), 3, p.1277 - 1285, 1999/00

no abstracts in English

JAEA Reports

Effects of ligands on the solubility of tin

Oda, Chie; *

JNC-TN8400 98-001, 14 Pages, 1998/11

JNC-TN8400-98-001.pdf:0.38MB

Solubilities of amorphous stannic oxide, SnO$$_{2}$$ (am) in Na-ClO$$_{4}$$-Cl-SO$$_{4}$$ aqueous systems were measured to quantitatively investigate the influences of the ligands OH$$^{-}$$, Cl$$^{-}$$ and SO$$_{4}^{2-}$$ on solubilities. They were also measured in bentonite equilibrated solutions to discuss the behavior of tin under a repository condition of a high-revel radioactive waste. The solubility data in sodium perchlorate media in the range of pH from 6 to 11 showed pH dependency, and the hydrolysis constants of tin (IV) were determined (Amaya, et al., 1997). No significant changes in solubilities with the variation in Cl$$^{-}$$, SO$$_{4}^{2-}$$ concentrations were observed in Na-ClO$$_{4}$$-Cl-SO$$_{4}$$ aqueous systems, so this indicates that chloride and sulfate species were less effective than hydroxide complexes. On the other hand, solubilities in bentonite equilibrated solutions were higher than solubilities of other experiments in simple systems. These results suggest that (1) other complexes of tin except hydroxide, chloride or sulfate complexes of tin (IV) may dominantly exist in aqueous phase, (2)solid phase other than SnO$$_{2}$$ (am) may limit the solubility of tin under repository conditions.

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