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Journal Articles

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Oku, Takayuki; Takata, Shinichi; Hiroi, Kosuke; Iwata, Takahiro*

J-PARC 22-02; J-PARC MLF Annual Report 2021, p.6 - 7, 2022/03

We carried out spin contrast variation neutron powder diffractometry of glutamic acid crystal. The diffraction peak intensities varied as a function of proton polarization. We extracted the structure factor of hydrogen atoms from the variation of peak intensities.

JAEA Reports

Stabilization treatment of Pu-bearing organic materials

Morishita, Kazuki; Sato, Takumi; Onishi, Takashi; Seki, Takayuki*; Sekine, Shinichi*; Okitsu, Yuichi*

JAEA-Technology 2021-024, 27 Pages, 2021/10


In the case of Plutonium (Pu)-bearing organic materials, organic materials are decomposed by alpha rays emitted mainly from Pu to generate hydrogen gas and other substances. Therefore, to safely store Pu-bearing organic materials for an extended period of time, organic materials must be eliminated. In addition, carbide and nitride fuels must be converted into oxides for safe storage in order to prevent the exothermal reaction of these fuels with oxygen/moisture in air. A survey of the literature on the stabilization treatment of Pu-bearing organic materials confirmed that organic materials can be decomposed and removed by heating at 950 $$^{circ}$$C (1223.15 K) or greater in air. Furthermore, based on the calculated thermodynamic parameters of oxidation reaction of carbide and nitride fuels in air, it was estimated that these fuels would be oxidized in air at 950 $$^{circ}$$C because the equilibrium oxygen partial pressure in the oxidation reaction at 950 $$^{circ}$$C was lower than 2.1$$times$$10$$^{4}$$ Pa (oxygen partial pressure in air). Therefore, it was decided to stabilize Pu-bearing organic materials by heating at 950 $$^{circ}$$C in air to remove the organic materials and oxidize the carbide and nitride fuels. As a mock-up test to remove the organic materials, thin sheets of epoxy resin were heated in air. The changes in appearance and weight before and after heating in air showed that organic materials can be removed. After the mock-up test, Pu-bearing organic materials were also stabilized by heating in the similar condition.

Journal Articles

Magnetically navigated protein transduction in vivo using iron oxide-nanogel chaperone hybrid

Kawasaki, Riku*; Sasaki, Yoshihiro*; Nishimura, Tomoki*; Katagiri, Kiyofumi*; Morita, Keiichi*; Sekine, Yurina; Sawada, Shinichi*; Mukai, Sadaatsu*; Akiyoshi, Kazunari*

Advanced Healthcare Materials, 10(9), p.2001988_1 - 2001988_8, 2021/05

 Times Cited Count:6 Percentile:65.6(Engineering, Biomedical)

Systems for "protein transduction", the intracellular delivery of functional proteins, are needed to address the deliverability challenges of protein therapy, but protein transfer in vivo remains difficult. In this study, we have developed a magnetically induced in vivo protein transfection system using a magnetic nanogel chaperone (MC) composed of iron oxide nanoparticles and polysaccharide nanogels. Experiments using an oral cancer model have shown that this MC system is useful for cancer treatment.

Journal Articles

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Ohara, Takashi; Takata, Shinichi; Hiroi, Kosuke; Morikawa, Toshiaki*; et al.

Journal of Applied Crystallography, 54(2), p.454 - 460, 2021/04


 Times Cited Count:1 Percentile:20.14(Chemistry, Multidisciplinary)

We developed a spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, namely, the contribution of hydrogen atoms to a crystal structure factor. Crystals of L-glutamic acid were dispersed in a dpolystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy (TEMPO methacrylate) to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

Journal Articles

Effects of interaction between molten zircaloy and irradiated MOX fuel on the fission product release behavior

Tanaka, Kosuke; Miwa, Shuhei; Sato, Isamu; Hirosawa, Takashi; Sekine, Shinichi; Osaka, Masahiko; Obayashi, Hiroshi; Koyama, Shinichi

Journal of Nuclear Science and Technology, 51(7-8), p.876 - 885, 2014/07

 Times Cited Count:5 Percentile:37.74(Nuclear Science & Technology)

As a first step for obtaining experimental data on the effects of high-temperature chemical interaction on fission product (FP) release behavior, we focused on the dissolution of irradiated uranium plutonium mixed oxide (MOX) fuel by molten zircaloy (Zry), and carried out a heating test under the reducing atmosphere. Pieces of an irradiated MOX fuel pellet and cladding were subjected to the heating test at 2373 K for 5 min. The fractional release rate of cesium (specifically $$^{137}$$Cs) was monitored during the test and its release behavior was evaluated. The observation of microstructures and measurements of elemental distribution in the heated specimen were also performed. We demonstrated experimentally that the fuel dissolution by molten Zry accelerated the release of Cs from the fuel pellets.

JAEA Reports

Evaluation of fission product and actinide release behaviors focusing on their chemical forms; Phase relation and fission product release behavior resulting from interaction between molten zircaloy and irradiated MOX fuel

Tanaka, Kosuke; Miwa, Shuhei; Sato, Isamu; Hirosawa, Takashi; Sekine, Shinichi; Seki, Takayuki*; Tokoro, Daishiro*; Obayashi, Hiroshi; Koyama, Shinichi

JAEA-Research 2013-022, 62 Pages, 2014/01


In order to establish the method for heating tests focused on the fission product release resulting from the high temperature chemical interaction between fuel and cladding material and to obtain the novel data on fission product release behaviors, the heating test was carried out with irradiate MOX fuel pellet and cladding.

JAEA Reports

Evaluation of irradiation behavior on oxide dispersion strengthened (ODS) steel claddings irradiated in Joyo/CMIR-6

Yano, Yasuhide; Otsuka, Satoshi; Yamashita, Shinichiro; Ogawa, Ryuichiro; Sekine, Manabu; Endo, Toshiaki; Yamagata, Ichiro; Sekio, Yoshihiro; Tanno, Takashi; Uwaba, Tomoyuki; et al.

JAEA-Research 2013-030, 57 Pages, 2013/11


It is necessary to develop the fast reactor core materials, which can achieve high-burnup operation improving safety and economical performance. Ferritic steels are expected to be good candidate core materials to achieve this objective because of their excellent void swelling resistance. Therefore, oxide dispersion strengthened (ODS) ferritic steel and 11Cr-ferritic/martensitic steel (PNC-FMS) have been respectively developed for cladding and wrapper tube materials in Japan Atomic Energy Agency. In this study, the effects of fast neutron irradiation on mechanical properties and microstructure of 9Cr-and 12Cr-ODS steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the CMIR-6 at temperatures between 420 and 835$$^{circ}$$C to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures.

Journal Articles

Restructuring and redistribution of actinides in Am-MOX fuel during the first 24h of irradiation

Tanaka, Kosuke; Miwa, Shuhei; Sekine, Shinichi; Yoshimochi, Hiroshi; Obayashi, Hiroshi; Koyama, Shinichi

Journal of Nuclear Materials, 440(1-3), p.480 - 488, 2013/09

 Times Cited Count:8 Percentile:54.24(Materials Science, Multidisciplinary)

In order to confirm the effect of minor actinide addition on irradiation behavior of MOX fuel pellets, 3% and 5% americium-containing MOX (Am-MOX) fuels were irradiated for 10 minutes at 43 kW/m and for 24 hours at 45 kW/m in the experimental fast reactor Joyo. Two nominal values of the fuel pellet oxygen-to-metal ratio (O/M), 1.95 and 1.98, were used as a test parameter. Emphasis was placed on the behavior of restructuring and redistribution of actinides which directly affect the fuel performance and the fuel design for fast reactors. Microstructural evolutions in the fuels were observed by optical microscopy and redistribution behavior of constituent elements was determined by mapping and quantitative point analyses of EPMA.

Journal Articles

Morphology-controlled synthesis of Mo compounds from a nitric acid solution by the microwave heating and/or Zr-addition

Osaka, Masahiko; Tanaka, Kosuke; Sekine, Shinichi; Akutsu, Yoko; Suzuki, Tatsuya*; Mimura, Hitoshi*

Journal of Nuclear Materials, 427(1-3), p.384 - 388, 2012/08

 Times Cited Count:4 Percentile:32.44(Materials Science, Multidisciplinary)

Morphology-controlled synthesis of Mo compounds from a nitric acid solution by microwave heating was investigated for effective utilizations of Mo fission product from a high level nuclear waste. The microwave heating method was revealed to greatly accelerate crystallization and crystal growth of the synthesized powder. Addition of a small amount of Zr stabilized synthesis of a hexagonal-MoO$$_{3}$$ powder. Furthermore, the microwave heating with Zr-addition has synthesized a specific urchin-like shaped hexagonal-MoO$$_{3}$$ crystal having a good crystallinity. The present methods would be useful for effective utilization of Mo from high level nuclear waste in terms of their practicability and ability to the morphology control.

Journal Articles

Effect of fine precipitate on void swelling behavior in heavily-irradiated modified SUS316 stainless steels for fast reactor application

Yamashita, Shinichiro; Sekine, Manabu*; Akasaka, Naoaki

Materia, 47(12), P. 624, 2008/12

no abstracts in English

Journal Articles

Methanol permeation properties of crosslinked-PTFE electrolyte membranes for DMFC applications

Sekine, Toshihiko; Sawada, Shinichi; Yamaki, Tetsuya; Asano, Masaharu; Suzuki, Akihiro*; Terai, Takayuki*; Yoshida, Masaru

Transactions of the Materials Research Society of Japan, 31(4), p.871 - 874, 2006/12

no abstracts in English

Journal Articles

Fabrication technology for MOX fuel containing AmO$$_{2}$$ by an in-cell remote process

Yoshimochi, Hiroshi; Ishi, Yohei; Seki, Takayuki*; Mondo, Kenji; Sekine, Shinichi*; Koyama, Shinichi

Saikuru Kiko Giho, (28), p.9 - 20, 2005/09

An in-cell remote fabrication technique has been developed for MOX fuel pellets containing 3 and 5% americium (Am-MOX) at the Alpha-gamma Facility (AGF) in O-arai Engineering Center. A series of fuel pellet and the pin fabrication apparatuses were systematically installed in hot cell to make fabrication flow easier. After cold run and some modifications, they were remotely controlled from a panel in the operation room outside the hot cell as much as possible. From a preliminary UO2 pellet test and consequently plutonium pellet fabrication run, actual range of ball milling time, pressing and sintering condition were focused for Am-MOX pellet fabrication. As the next step, moisturized atmosphere was found out to remove the heterogeneity structure of 5% Am-MOX pellet. Finally, we established an optimized fabrication condition of 5% Am-MOX pellet sintered at 1700$$^{circ}$$C for 3h in an atmosphere of 5% H2-95% Ar with total moisture of 2000 ppm. Moreover it is important that the atmosphere has to be changed to dry gas at 800$$^{circ}$$C during cool down.

JAEA Reports

Effect of Oxygen Potential on the Sintering behavior of MOX fuel containing Am

Miwa, Shuhei; Osaka, Masahiko; Yoshimochi, Hiroshi; Tanaka, Kenya; Seki, Takayuki*; Sekine, Shinichi*

JNC TN9400 2005-023, 43 Pages, 2005/04


The effect of oxygen potential on the sintering behavior of MOX fuel containing Am (Am-MOX) was investigated. Green pellets of Am-MOX were prepared by a conventional powder metallurgical technique. For Am-MOX fuel pellets sintered at various oxygen potential conditions, density measurement, microstructural observation and elements analyses by EPMA were performed High density pellets having good structure were obtained due to oxygen potential change of sintering atmosphere from high oxygen potential to low oxygen potential at 800$$^{circ}$$C in the cooling process.For the pellets sintered at -520 kJ/mol, -390 kJ/mol and -340 kJ/mol, the sintered density increases with increase of oxygen potential up to -390 kJ/mol (threshold oxygen potential), then decreases above the threshold oxygen potential. This tendency is similar to that observed in the (U,Gd)O$$_{2 }$$ system. The differences of sintering behavior for Am-MOX pellets which were observed by changing the oxygen potential were attributable to the difference of pore structure, which was supposed to be caused by the valence state of Am in the oxides. On the other hands, the grain size of Am-MOX pellet sintered at -520 kJ/mol was almost the same as that at -390 kJ/mol. Homogeneous distribution of U, Pu and Am was obtained at pellets sintered both -520 and -390 kJ/mol in these sintering conditions. For the pellets sintered at 1500$$^{circ}$$C , 1600$$^{circ}$$C , 1700$$^{circ}$$C , the high dense pellets are obtained, therefore This results shows the the possibility of fabrication of good fuel pellets at lower temperature than 1700$$^{circ}$$C

JAEA Reports

Phase relation of (U,Pu,Am)O$$_{2-x}$$

Osaka, Masahiko; Miwa, Shuhei; Mondo, Kenji; Ozaki, Yoko; Ishi, Yohei; Yoshimochi, Hiroshi; Seki, Takayuki*; Sekine, Shinichi*; Ishida, Takashi*; Tanaka, Kenya

JNC TN9400 2005-002, 40 Pages, 2005/03


An experimental investigation for the phase relation of (U,Pu,Am)O$$_{2-x}$$ was performed with XRD, ceramography and DTA. Although lattice parameter tended to increase with increases of Am content and O/M ratio, its slope differed from that of (U,Pu)O$$_{2-x}$$. A drastic structural change was observed around O/M=1.98. Besides, many DTA peaks, which could never be seen in the case of (U,Pu)O$$_{2-x}$$, were observed above O/M=1.98.These results were interpreted with a hypothesis that all Am were trivalent and equivalent amount of U became pentavalent. The dependence of lattice parameter on Am content could be expressed well by using a model with ionic radii of each element. Also the structural change around O/M=1.98 could be explained as caused by valence states of each element. It was concluded from these interpretation that all Am in (U,Pu,Am)O$$_{2-x}$$ were likely to exist as trivalent state.

Journal Articles

Measurement of Burn-up in FBR MOX Fuel Irradiated up to High Burn-up

Koyama, Shinichi; Osaka, Masahiko; Sekine, Takashi; Morozumi, Katsufumi; Namekawa, Takushi;

Journal of Nuclear Science and Technology, 40(2), p.998 - 1013, 2003/02

 Times Cited Count:23 Percentile:80.96(Nuclear Science & Technology)


Journal Articles

Recent studies of unstable nuclei far from stability with the on-line isotope separators of JAERI

Sekine, Toshiaki; Ichikawa, Shinichi; Osa, Akihiko; Koizumi, Mitsuo; Iimura, Hideki; Tsukada, Kazuaki; Nishinaka, Ichiro; Hatsukawa, Yuichi; Nagame, Yuichiro; Asai, Masato*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 239(1), p.127 - 131, 1999/00

 Times Cited Count:2 Percentile:21.21(Chemistry, Analytical)

no abstracts in English

Journal Articles

Conversion electron measurements in $$^{125,127}$$Ba

Iimura, Hideki; Ichikawa, Shinichi; Sekine, Toshiaki; *; Oshima, Masumi

Exotic Nuclei and Atomic Masses (ENAM98), p.544 - 547, 1998/00

no abstracts in English

Journal Articles

Solubility of neptunium(IV) hydrous oxide in aqueous solutions

Nakayama, Shinichi; Yamaguchi, Tetsuji; Sekine, Keiichi

Radiochimica Acta, 74(1), p.15 - 19, 1996/01

no abstracts in English

Oral presentation

An Estimation of the applicability of $$^{11}$$B$$_{4}$$C for moderator

Donomae, Takako; Tachi, Yoshiaki; Onose, Shoji; Matsumoto, Shinichiro; Ito, Masahiko; Sekine, Manabu*

no journal, , 

no abstracts in English

Oral presentation

Development of fabrication technique for MOX pellet containing Americium by the remote control, 12; Synthesis evaluation on remote fuel fabrication in small hot cell

Yoshimochi, Hiroshi; Ishi, Yohei; Tanaka, Kenya; Sekine, Shinichi*; Seki, Takayuki*

no journal, , 

no abstracts in English

54 (Records 1-20 displayed on this page)