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JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2022

Kokubun, Yuji; Nakada, Akira; Seya, Natsumi; Nagaoka, Mika; Koike, Yuko; Kubota, Tomohiro; Hirao, Moe; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; et al.

JAEA-Review 2023-052, 118 Pages, 2024/03

JAEA-Review-2023-052.pdf:3.67MB

Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2022. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Journal Articles

Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:43 Percentile:96.93(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:259 Percentile:99.73(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Reverse Monte Carlo simulation approach on the amorphous structure of C$$_{59}$$N

Ferdows, M.; Suzuya, Kentaro; Kawakita, Yukinobu; Kohara, Shinji*; Kodama, Katsuaki; Yamamoto, Kazunori; Shamoto, Shinichi; Hirata, Takamichi*; Omote, Kenji*; Kasama, Yasuhiko*; et al.

Abstracts of 7th International Symposium on Advanced Materials in Asia-Pacific (NT 2010)/JAIST International Symposium on Nano Technology 2010 (7th ISAMAP), p.25 - 28, 2010/09

We performed Reverse Monte Carlo analysis (RMCA) to study amorphous structure of a heterofullerene, C$$_{59}$$N by using pulsed neutron powder diffraction data. The scattering function S(Q) shows that the structure is amorphous, while the atomic pair distribution function (PDF) shows that the local structure is similar to that of C$$_{60}$$. Obtained structures strongly depend on the initial models. Problems for this RMCA method are discussed.

Journal Articles

A New method for separating the $$D$$$$_{3}$$ and $$C$$$$_{2v}$$ isomers of C$$_{78}$$

Han, A. H.*; Wakahara, Takatsugu*; Maeda, Yutaka*; Akasaka, Takeshi*; Fujitsuka, Mamoru*; Ito, Osamu*; Yamamoto, Kazunori; Kako, Masahiro*; Kobayashi, Kaoru*; Nagase, Shigeru*

New Journal of Chemistry, 33(3), p.497 - 500, 2009/03

 Times Cited Count:7 Percentile:32.52(Chemistry, Multidisciplinary)

A new chemical method can be applied to isolate the isomers of C$$_{78}$$. The photochemical cycloaddition of a mixture of C$$_{78}$$($$D$$$$_{3}$$) and C$$_{78}$$($$C$$$$_{2v}$$) with disilirane affords only the mono-adduct of the $$C$$$$_{2v}$$ isomer of C$$_{78}$$. The counter part (C$$_{78}$$($$D$$$$_{3}$$)) does not give the mono-adduct with disilirane. The $$D$$$$_{3}$$ isomer itself and the adduct of the $$C$$$$_{2v}$$ isomer of C$$_{78}$$ with disilirane was easily separated by a HPLC procedure. A facile oxidative desilylation of the adduct took place, resulting in the formation of pristine C$$_{78}$$($$C$$$$_{2v}$$). In this context, the separation and the isolation of two isomers of C$$_{78}$$($$C$$$$_{2v}$$) and C$$_{78}$$($$D$$$$_{3}$$) were successfully accomplished by using a silylation-oxidative desilylation process.

Journal Articles

Does Gd@C$$_{82}$$ have an anomalous endohedral structure? Synthesis and single crystal X-ray structure of the carbene adduct

Akasaka, Takeshi*; Kono, Takayoshi*; Takematsu, Yuji*; Nikawa, Hidefumi*; Nakahodo, Tsukasa*; Wakahara, Takatsugu*; Ishitsuka, Midori*; Tsuchiya, Takahiro*; Maeda, Yutaka*; Liu, M. T. H.*; et al.

Journal of the American Chemical Society, 130(39), p.12840 - 12841, 2008/10

 Times Cited Count:76 Percentile:84.42(Chemistry, Multidisciplinary)

We report here the results on single crystal X-ray crystallographic analysis of the Gd@C$$_{82}$$ carbene adduct (Gd@C$$_{82}$$(ad), Ad=adamantylidene). The Gd atom in Gd@C$$_{82}$$(Ad) is located at an off-centered position near a hexagonal ring in the C2v-C$$_{82}$$ cage, as found for M@C$$_{82}$$ (M = Sc and La) and La@C$$_{82}$$(Ad). Theoretical calculation also confirms the position of the Gd atom in the X-ray crystal structure.

Journal Articles

Bulk copper-nanodiamond nanocomposites; Processing and properties

Correia, J, B.*; Livramento, V.*; Shohoji, Nobumitsu*; Tresso, E.*; Yamamoto, Kazunori; Taguchi, Tomitsugu; Hanada, Kotaro*; Osawa, Eiji*

Materials Science Forum, 587-588, p.443 - 447, 2008/00

Nanostructured metals and nanocomposites are ways to address the low hardness problem, provided the nanostructured material is thermally stable during processing and service. In the present research, Cu composite powders, with 5 to 30 at % nanodiamond, were consolidated into bulk samples. The copper-nanodiamond composite powders were vacuum encapsulated and extruded at 600 $$^{circ}$$C. A significant proportion of the initial hardness in the powders is retained after extrusion. Transmission electron microscopy of the extruded material indicates good bonding between the nanodiamond particles and the copper matrix. Raman spectroscopy on the consolidated samples evidences the presence of graphite, possibly due to partial disintegration of ultradisperse nanodiamond agglomerates.

Journal Articles

TEM studies of nanocarbons and nanodiamonds (ND); Mechanical milling of ND and Cu

Yamamoto, Kazunori; Taguchi, Tomitsugu; Hanada, Kotaro*; Osawa, Eiji*; Inakuma, Masayasu*; Livramento, V.*; Correia, J, B.*; Shohoji, Nobumitsu*

Diamond and Related Materials, 16(12), p.2058 - 2062, 2007/12

 Times Cited Count:6 Percentile:31.31(Materials Science, Multidisciplinary)

Nano-sized polymorphs of carbon continue to attract much attention of scientists and provide new targets of examination with transmission electron microscope (TEM). We present here TEM images of a number of nanocarbons which played critical roles in some stage of their R&D, such as mechanical alloying of Cu and nanodiamond, diamond from soot, and short carbon nanocylinders by milling with microbeads. Emphasis is placed on nanodiamonds.

Journal Articles

Further studies on copper nanocomposite with dispersed single-digit-nanodiamond particles

Hanada, Kotaro*; Yamamoto, Kazunori; Taguchi, Tomitsugu; Osawa, Eiji*; Inakuma, Masayasu*; Livramento, V.*; Correia, J, B.*; Shohoji, Nobumitsu*

Diamond and Related Materials, 16(12), p.2054 - 2057, 2007/12

 Times Cited Count:26 Percentile:70.43(Materials Science, Multidisciplinary)

This paper describes the microstructures and mechanical properties of Cu nanocomposites containing 0-30 at% diamond nanoparticles. The Cu nanocomposite powders are fabricated by mechanical milling method and are consolidated by spark plasma sintering and hot extrusion. Microstructural observation shows that the homogeneous distribution of diamond nanoparticles in the Cu nanocomposite can be achieved by extrusion with large plastic deformation, in spite of 20 at% diamond content, and that the nanocomposite with homogeneous distribution of diamond nanoparticles has ultra-fine grain structure, approximately 50 nm. Vickers hardness and compression tests on the SPS-consolidated and hot-extruded samples show that the detonation nanodiamond dispersed homogeneously in the Cu matrix enhances the mechanical properties.

JAEA Reports

Analysis of ground water from boreholes, river water and precipitation in the Underground Research Laboratory Project

Kunimaru, Takanori; Shibano, Kazunori; Kurikami, Hiroshi; Tomura, Goji; Hara, Minoru; Yamamoto, Hajime*

JAEA-Data/Code 2007-015, 113 Pages, 2007/11

JAEA-Data-Code-2007-015.pdf:6.62MB

In the Horonobe Underground Research Laboratory (URL) Project, ground water from boreholes, river water and precipitation have been preiodically analyzed for the environmental monitoring since the fiscal year 2001. This report shows the data set of water chemistry since the fiscal year 2001 to the fiscal year 2006.

JAEA Reports

Study on Carbon Nano-encapulates for Processing and Utilizing Radionuclides

Yamamoto, Kazunori

JNC TN1400 2005-002, 74 Pages, 2005/03

JNC-TN1400-2005-002.pdf:12.23MB

A carbon nanocapsule has a polyhedral outer shell of nested, concentric layers of carbon. The shell defines an internal cavity where a metal is encapsulated. A radionuclide particle may be physically enclosed within the cavity completely, and the cavity protects it perfectly against attack of water molecules. Considering intrinsic physical stability of graphene and chemical stability of carbon under reducing condition, this carbon structure may be a perfect barrier to extremely long-term release of radionuclides. By choosing La as representative of FP, encapsulation mechanism of nanocapsules has been investigated for finding optimized condition that complete encapsulation is achieved. Encapsulation of LaC2 within carbon nanocapsules increased drastically from by-product to major product. New mechanism has been proposed for synthesizing LaC2 containing carbon nanocapsules.

Journal Articles

Synthesis and ${it in vivo}$ evaluation of BPA-Gd-DTPA complex as an MRI contrast agent and as a carrier for neutron capture therapy

Takahashi, Kazunori*; Nakamura, Hiroyuki*; Furumoto, Shozo*; Yamamoto, Kazuyoshi; Matsumura, Akira*; Fukuda, Hiroshi*; Yamamoto, Yoshinori*

Proceedings of 11th World Congress on Neutron Capture Therapy (ISNCT-11) (CD-ROM), 1 Pages, 2004/10

We synthesized a BPA-Gd-DTPA compound, as a carrier for neutron capture therapy to be used for MRI contrast media. Pinanediol was used as the protective group for B(OH)2 group of BPA, and the BPA unit was connected to the DTPA framework through an amide bond. The biodistribution studies were performed after injection of the compound into AH109A hepatoma bearing Donryu rats. The concentrations of Gd and boron were measured by prompt g-ray analyses. The tumor uptakes (% ID/g) were 1% and 0.3% at 20 min and 60 min after injection, respectively and were higher than that of carborane-Gd-DTPA, which we previously reported. However, liver and kidney uptake was very high and tumor/blood ratio was very low (0.38) compared to that of BPA itself (ca. 3.0). Alfa autoradiogram of a tumor bearing rat showed higher concentration of boron in the tumor compared to surrounding muscle and very high in the intestine. Although tumor selectivity of the compound was higher than that of carborane-Gd-DTPA, further studies of the synthesis and in vivo evaluation of better binary compounds are continuing.

Journal Articles

Bulk Synthesis and Characterization of Carbon Nanocapsules Containing Lanthanum Carbide

Yamamoto, Kazunori; Wakahara, Takatsugu*; Akasaka, Takeshi*

MA2004-01 (CD-ROM), 0 Pages, 2003/00

Carbon nanocapsules stuffed with lanthanum carbide did not degrade after exposure to air for considerable length of time, suggesting the carbide particle was completely enclosed within the carbon shell, although the carbide readily hydrolyze in moist air. In this study we present our optimization study that attempted to determine the effect of variations of the processing conditions on the morphorogy of the carbon nanocapsules.

JAEA Reports

Improvement for simulation system for emergency release of radio active substance

Miyauchi, Kazuya*; Yamamoto, Asao*; Yatake, Yoichi*; Kasuya, Kazunori*

JNC TJ4440 2002-001, 197 Pages, 2002/03

JNC-TJ4440-2002-001.pdf:8.54MB

None

Journal Articles

ITER engineering design

Shimomura, Yasuo; Tsunematsu, Toshihide; Yamamoto, Shin; Maruyama, So; Mizoguchi, Tadanori*; Takahashi, Yoshikazu; Yoshida, Kiyoshi; Kitamura, Kazunori*; Ioki, Kimihiro*; Inoue, Takashi; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 78(Suppl.), 224 Pages, 2002/01

no abstracts in English

JAEA Reports

None

Wada, Yukio; Funasaka, Hideyuki; Myochin, Munetaka; Yamamoto, Kazunori; Harada, Hideo; ;

PNC TN8100 96-005, 16 Pages, 1996/01

PNC-TN8100-96-005.pdf:1.6MB

no abstracts in English

Journal Articles

Superconducting transition at 12.5K in Rb$$_{x}$$C$$_{60}$$

Funasaka, Hideyuki; Sugiyama, Kenji; Yamamoto, Kazunori; Takahashi, Takeshi

Chemical Physics Letters, 241(3), p.154 - 160, 1995/07

 Times Cited Count:3 Percentile:14.17(Chemistry, Physical)

None

Journal Articles

Synthesis of lanthanum compound encapsulated within carbon nanoparticles

Funasaka, Hideyuki; Sugiyama, Kenji; Yamamoto, Kazunori; Takahashi, Takeshi

Chemical Physics Letters, 236(3), p.277 - 284, 1995/04

 Times Cited Count:5 Percentile:21.89(Chemistry, Physical)

None

Journal Articles

Magnetic properties of Gd@C$$_{82}$$ metallofullerene

Funasaka, Hideyuki; Oda, Yoshihiro; Sakurai, Koji*; Yamamoto, Kazunori; Takahashi, Takeshi

Chemical Physics Letters, 232(3), p.273 - 277, 1995/01

 Times Cited Count:103 Percentile:95.04(Chemistry, Physical)

None

49 (Records 1-20 displayed on this page)