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Journal Articles

Microstructural stability of ODS steel after very long-term creep test

Oka, Hiroshi; Tanno, Takashi; Yano, Yasuhide; Otsuka, Satoshi; Kaito, Takeji; Tachi, Yoshiaki

Journal of Nuclear Materials, 547, p.152833_1 - 152833_7, 2021/04

 Times Cited Count:1 Percentile:81.22(Materials Science, Multidisciplinary)

In order to evaluate the stability of nano-sized oxide particles and matrix structure of ODS cladding tube, which are the determinants of their high temperature strength, the microstructural observation was carried out after internal pressurized creep test at 700$$^{circ}$$C for over 45,000 hours. The specimens were the as-received and crept specimens of 9Cr-ODS steel with tempered martensite and 12Cr-ODS steel with recrystallized ferrite. Small platelet was cut out from the crept pressurized tube, then thinned to foil. Microstructural observation was conducted with TEM JEOL 2010F. As a result of the observation, it was confirmed that the size and number density of the nano-sized particles were almost unchanged even after the creep test. In addition, the tempered martensite structure, which is one of the determinants of the creep strength of 9Cr-ODS steel, was not significantly different between the as-received and crept specimen, indicating the stability of their matrix structure.

Journal Articles

Development of ODS tempered martensitic steel for high burn up fuel cladding tube of SFR

Otsuka, Satoshi; Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Tachi, Yoshiaki; Kaito, Takeji; Hashidate, Ryuta; Kato, Shoichi; Furukawa, Tomohiro; Ito, Chikara; et al.

2018 GIF Symposium Proceedings (Internet), p.305 - 314, 2020/05

Oxide Dispersion Strengthened (ODS) steel has been developed worldwide as a high-strength and radiation-tolerant steel used for advanced nuclear system. Japan Atomic Energy Agency (JAEA) has been developing ODS steel as the primary candidate material of Sodium cooled Fast Reactor (SFR) high burn-up fuel cladding tube. Application of high burn-up fuel to SFR core can contribute to improvement of economical performance of SFR in conjunction with volume and hazardousness reduction of radioactive waste. This paper described the current status and future prospects of ODS tempered martensitic steel development in JAEA for SFR fuel application.

Journal Articles

Inverse pole figure mapping of bulk crystalline grains in a polycrystalline steel plate by pulsed neutron Bragg-dip transmission imaging

Sato, Hirotaka*; Shiota, Yoshinori*; Morooka, Satoshi; Todaka, Yoshikazu*; Adachi, Nozomu*; Sadamatsu, Sunao*; Oikawa, Kenichi; Harada, Masahide; Zhang, S.*; Su, Y.; et al.

Journal of Applied Crystallography, 50(6), p.1601 - 1610, 2017/12

 Times Cited Count:11 Percentile:78.1(Chemistry, Multidisciplinary)

Journal Articles

Fano factor evaluation of diamond detectors for alpha particles

Shimaoka, Takehiro*; Kaneko, Junichi*; Sato, Yuki; Tsubota, Masakatsu*; Shimmyo, Hiroaki*; Chayahara, Akiyoshi*; Watanabe, Hideyuki*; Umezawa, Hitoshi*; Mokuno, Yoshiaki*

Physica Status Solidi (A), 213(10), p.2629 - 2633, 2016/10

 Times Cited Count:3 Percentile:20.49(Materials Science, Multidisciplinary)

Journal Articles

Chemical composition of insoluble residue generated at the Rokkasho Reprocessing Plant

Yamagishi, Isao; Odakura, Makoto; Ichige, Yoshiaki; Kuroha, Mitsuhiko; Takano, Masahide; Akabori, Mitsuo; Yoshioka, Masahiro*

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1113 - 1119, 2015/09

The characteristics of insoluble residues in fine suspension at the Rokkasho Reprocessing Plant were analyzed. The insoluble residues were washed with oxalic acid solution to dissolve zirconium molybdate residues. XRD profiles of unwashed residues showed the presence of a noble metal alloy, zirconium molybdate, and zirconia, but zirconium molybdate was not found after washing. More than 50% of the Sb-125 and Pu in thee residues was washed out as well. The noble metal alloy composed of Mo, Tc, Ru, Rh, and Pd occupied more than 90% of the total weight of 12 elements (Ca, Cr, Fe, Ni, Zr, Mo, Tc, Ru, Rh, Pd, Te, and U) found in the residues. In consideration of the chemical forms of 12 elements, the alloy-to-residue weight ratio was evaluated to be 64% and 78% with and without 18% of an unknown component, respectively.

Journal Articles

Nuclear reactor calculations

Okumura, Keisuke; Oka, Yoshiaki*; Ishiwatari, Yuki*

Nuclear Reactor Design, p.49 - 126, 2014/00

As necessary knowledge for nuclear reactor design, fundamental methods of nuclear reactor calculations are described. First, we explain, in an easy-to-understand manner, what kinds of numerical methods and procedures are employed in the codes which treat nuclear data processing, lattice calculation, lattice burnup calculation, core calculation, nuclear and thermal-hydraulic coupled calculation, core burnup calculation and space-dependent core calculation. Next we show the calculated examples of the optimizations for a fuel loading pattern and control rod insertion pattern in the thermal-hydraulic coupled core burnup calculation. Furthermore, we describe the methods of the plant dynamics analyses using a simple node junction model for the heat transfer calculation. The plant dynamics cover the analyses of control and startup properties, reactor stability, and safety analysis.

Journal Articles

A Large-scale three-dimensional simulation on thermal-hydraulics in a fuel bundle for SCWR

Misawa, Takeharu; Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*; Oka, Yoshiaki*

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo (SNA & MC 2013) (CD-ROM), 2 Pages, 2013/10

Journal Articles

Radiation hardening and IASCC susceptibility of extra high purity austenitic stainless steel

Ioka, Ikuo; Ishijima, Yasuhiro; Usami, Koji; Sakuraba, Naotoshi; Kato, Yoshiaki; Kiuchi, Kiyoshi

Journal of Nuclear Materials, 417(1-3), p.887 - 891, 2011/10

 Times Cited Count:7 Percentile:53.57(Materials Science, Multidisciplinary)

Fe-25Cr-35Ni EHP alloy was developed with conducting the countermeasure for IASCC. It is composed to adjust major elements, to remove harmful impurities and so on. The specimens were irradiated at 553 K for 25000h using JRR-3. The fluence was estimated to be 1.5$$times$$10$$^{25}$$n/m$$^2$$. Type 304SS was also irradiated as a comparison material. SSRT test was conducted in oxygenated water at 561 K in 7.7 MPa. The fracture mode of EHP alloy was ductile. IGSCC was not observed in the fracture surface. On the other hand, the fraction of IGSCC on the fracture surface of type 304 was about 70%. Microstructural evolution of EHP and type 304 after irradiation was examined by TEM. The defects induced by irradiation mostly consisted of black dots and frank loops in both specimens. No void was also observed in grain and grain boundary of both specimens. There was a little difference in microstructure after irradiation. It is believed that EHP alloy is superior to type 304 in irradiation.

Journal Articles

Electronic structure of U(Ru$$_{1-x}$$Rh$$_{x}$$)$$_2$$Si$$_2$$ studied by laser angle-resolved photoemission spectroscopy

Yoshida, Rikiya*; Nakamura, Yoshiaki*; Fukui, Masaki*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Okawa, Mario*; Shin, S.*; Hirai, Masaaki*; Muraoka, Yuji*; et al.

Journal of Physics; Conference Series, 273, p.012021_1 - 012021_4, 2011/02

 Times Cited Count:0 Percentile:0.03

Journal Articles

Low temperature structure of FeSr$$_{2}$$YCu$$_{2}$$O$$_{6+delta}$$ magnetic superconductor

Mochiku, Takashi*; Hata, Yoshiaki*; Wuernisha, T.*; Igawa, Naoki; Hoshikawa, Akinori*; Ishigaki, Toru*; Yasuoka, Hiroshi*; Hirata, Kazuto*

Physica C, 470(Suppl.1), p.S158 - S159, 2010/12

 Times Cited Count:2 Percentile:13.13(Physics, Applied)

We have performed neutron powder diffraction of the superconducting FeSr$$_{2}$$YCu$$_{2}$$O$$_{6+}$$$$_{delta}$$ and the nonsuperconducting FeSr$$_{2}$$Y(Cu$$_{0.95}$$Zn$$_{0.05}$$)$$_{2}$$O$$_{6+}$$$$_{delta}$$ samples at low temperature and room temperature to investigate the relation between the crystal structure ant the physical properties. Neutron diffraction study indicates that the magnetic order in this compound is not long-range order because we observed no extra reflection due to the magnetic superstructure. We have observed structural anomaly related to Cu in the superconducting sample around 30 K although we could not observe it in the nonsuperconducting sample. There is possibility of the change of the charge distribution around 30 K in the superconducting sample.

Journal Articles

Signature of hidden order and evidence for periodicity modification in URu$$_2$$Si$$_2$$

Yoshida, Rikiya*; Nakamura, Yoshiaki*; Fukui, Masaki*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Okawa, Mario*; Shin, S.*; Hirai, Masaaki*; Muraoka, Yuji*; et al.

Physical Review B, 82(20), p.205108_1 - 205108_6, 2010/11

 Times Cited Count:56 Percentile:88.53(Materials Science, Multidisciplinary)

Journal Articles

Measurements of neutron capture cross section of $$^{237}$$Np for fast neutrons

Harada, Hideo; Nakamura, Shoji; Hatsukawa, Yuichi; Toh, Yosuke; Kimura, Atsushi; Ishiwatari, Yuki*; Yasumi, Atsushi*; Mabuchi, Yukio*; Nakagawa, Tsutomu*; Okamura, Kazuo*; et al.

Journal of Nuclear Science and Technology, 46(5), p.460 - 468, 2009/05

 Times Cited Count:4 Percentile:32.89(Nuclear Science & Technology)

The neutron capture cross section of $$^{237}$$Np has been measured for fast neutrons supplied at the center of the core in the Yayoi reactor. The activation method was used for the measurement, in which the amount of the product $$^{238}$$Np was determined by $$gamma$$-ray spectroscopy using a Ge detector. The representative neutron energy and the corresponding capture cross section of $$^{237}$$Np in the experiment were analytically deduced as 0.80 $$pm$$ 0.04 b at 0.214 $$pm$$ 0.009 MeV from the measured reaction rate by combining the energy dependence of the cross section in the nuclear data library ENDF/VII.0. The deduced cross section of $$^{237}$$Np at the representative neutron energy agrees with the evaluated data of ENDF/B-VII.0, but shows 15% larger value than that of JENDL-3.3 and 13% larger value than that of JENDL/AC-2008.

JAEA Reports

Establishment of advanced integration technology for site characterization of deep geological repository; Development of information synthesis and interpretation system; Annual report 2007 (Contract research)

Osawa, Hideaki; Ota, Kunio; Hama, Katsuhiro; Sawada, Atsushi; Takeuchi, Shinji; Amano, Kenji; Saegusa, Hiromitsu; Matsuoka, Toshiyuki; Miyamoto, Tetsuo; Toyoda, Gakuji; et al.

JAEA-Research 2008-085, 742 Pages, 2008/11

JAEA-Research-2008-085-1.pdf:26.22MB
JAEA-Research-2008-085-2.pdf:16.64MB
JAEA-Research-2008-085-3.pdf:28.27MB

This report shows the results the project for the establishment of comprehensive site characterization technology, entrusted from Natural Resources and Energy Agency, Ministry of Economy, Trade and Industry Natural Resources and Energy Agency in 2007.

Journal Articles

Research and development of a super fast reactor, 8; Heat transfer experiments around a simulated fuel rod with supercritical pressure water

Ezato, Koichiro; Akiba, Masato; Enoeda, Mikio; Suzuki, Satoshi; Seki, Yohji; Tanigawa, Hisashi; Tsuru, Daigo; Mori, Hideo*; Oka, Yoshiaki*

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

no abstracts in English

Journal Articles

Development of know-how and systematic techniques for characterisation of coastal geological environment at Horonobe

Yamanaka, Yoshiaki; Matsuoka, Toshiyuki; Asamori, Koichi; Ota, Kunio

Shadan Hojin Butsuri Tansa Gakkai Dai-119-Kai (Heisei-20-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.73 - 75, 2008/10

Characterisation of the coastal geological environment has now been running since July 2007 at Horonobe, northern Hokkaido, with the main aims of establishing a comprehensive coastal site characterisation technology and enhancing its reliability. Work carried out to date involves a survey and interpretation of the existing information, identification of key investigation issues and planning of ground exploration. Development of technical know-how and decision process for the work, in particular the geophysical surveys, has been initiated to provide "knowledge" to support a site characterisation project.

JAEA Reports

Study on high-performance fuel cladding materials; Joint research report in FY 2001-2005 (Phase 2) (Joint research)

Kiuchi, Kiyoshi; Ioka, Ikuo; Tanabe, Makoto*; Nanjo, Yoshiyasu*; Ogawa, Hiroaki; Ishijima, Yasuhiro; Tsukatani, Ichiro; Ochiai, Takamasa; Kizaki, Minoru; Kato, Yoshiaki; et al.

JAEA-Research 2006-023, 173 Pages, 2006/03

JAEA-Research-2006-023.pdf:20.51MB

The research concerning new cladding materials for ultra-high burnup of fuel elements with MOX fuels aiming at 100 GWd/t of BWR was pursued for 5 years from 2001 to 2005. On the Phase 1, the modified stainless steel of Fe-25Cr-35Ni-0.2Ti as fuel claddings and Nb-Mo alloy as a liner for inhibiting the pellet- clad interaction were selected as candidate materials, by evaluating fundamental properties required to BWR cladding materials, that are the nuclear economy, radioactivity, mass-transfer, irradiation properties, mechanical properties so on. On the present study, the making process of cladding tubes, lining by diffusion bonding, end plug by laser welding were developed and optimized, by considering the practical use of fuel elements consists of these candidates. The practical applicability was basically examined by irradiation tests using the accelerator of TIARA and the research reactor of JRR-3, for mainly confirming the resistance to IGSCC as one of the current important issues of BWR core materials of low carbon grade stainless steels. Creep and fatigue testing data were also obtained for evaluating the long performance of candidate materials. The behavior as fuel elements was analyzed with the safety calculation code for BWRs. The obtained results were established as a data base system, by considering the applicability to the fuel design and in-pile loop tests.

Journal Articles

Radiation hardening and -embrittlement due to He production in F82H steel irradiated at 250 $$^{circ}$$C in JMTR

Wakai, Eiichi; Jitsukawa, Shiro; Tomita, Hideki*; Furuya, Kazuyuki; Sato, Michitaka*; Oka, Keiichiro*; Tanaka, Teruyuki*; Takada, Fumiki; Yamamoto, Toshio*; Kato, Yoshiaki; et al.

Journal of Nuclear Materials, 343(1-3), p.285 - 296, 2005/08

 Times Cited Count:42 Percentile:93.27(Materials Science, Multidisciplinary)

The dependence of helium production on radiation-hardening and -embrittlement has been examined in a reduced-activation martensitic F82H steel doped with $$^{10}$$B, $$^{11}$$B and $$^{10}$$B+$$^{11}$$B irradiated at 250$$^{circ}$$C to 2.2 dpa. The total amounts of doping boron were about 60 massppm. The range of He concentration produced in the specimens was from about 5 to about 300 appm. Tensile and fracture toughness tests were performed after neutron irradiation. 50 MeV-He$$^{2+}$$ irradiation was also performed to implant about 85 appm He atoms at 120$$^{circ}$$C by AVF cyclotron to 0.03 dpa, and small punch testing was performed to obtain DBTT. Radiation-hardening of the neutron-irradiated specimens increased slightly with increasing He production. The 100 MPam$$^{1/2}$$ DBTT for the F82H+$$^{11}$$B, F82H+$$^{10}$$B+$$^{11}$$B, and F82H+$$^{10}$$B were 40, 110, and 155$$^{circ}$$C, respectively. The shifts of DBTT due to He production were evaluated as about 70$$^{circ}$$C by 150 appmHe and 115$$^{circ}$$C by 300 appmHe. The DBTT shift in the small punch testing was evaluated as 50$$^{circ}$$C.

Journal Articles

Rationalization of the fuel integrity and transient criteria for the super LWR

Yamaji, Akifumi*; Oka, Yoshiaki*; Ishiwatari, Yuki*; Liu, J.*; Koshizuka, Seiichi*; Suzuki, Motoe

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 7 Pages, 2005/05

Ensuring the fuel integrities is one of the most fundamental parts in the High Temperature Supercritical-Pressure Light Water Reactor. Most abnormal transient events of SCLWR-H last for a short period of time and the fuel rods are replaced after being irradiated in the core. In this study, the fuel integrity criteria are rationalized based on the fact that the fuel rod mechanical failures can be represented by the strain of the fuel rod cladding. A new fuel rod is designed with a Stainless Steel cladding. It is internally pressurized to reduce the stress on the cladding and also to increase the gap conductance between the pellet and the cladding. The fuel integrities both at normal operation and abnormal transient conditions are evaluated using the fuel analysis code FEMAXI-6 of JAERI.

Journal Articles

R&D of a MW-class solid-target for spallation neutron source

Kawai, Masayoshi*; Furusaka, Michihiro*; Kikuchi, Kenji; Kurishita, Hiroaki*; Watanabe, Ryuzo*; Li, J.*; Sugimoto, Katsuhisa*; Yamamura, Tsutomu*; Hiraoka, Yutaka*; Abe, Katsunori*; et al.

Journal of Nuclear Materials, 318, p.35 - 55, 2003/05

R&D works for MW class solid target composed of tungsten to produce pulsed intense neutron source has been made in order to construct a future scattering facility. Three methods were investigated to prevent corrosion of tungsten from water; those are hipping, brazing and electric coating in molten salt bath. Hipping condition was optimized to be 1500 degree C in the previous work: here small punch test shows highest load for crack initiation of hipped materials at the boundary of W/Ta. The basic techniques for the other two methods were developed. Erosion test showed that uncovered W is susceptible of flowing water velocity. At high velocity w is easy to be eroded. For solid target design slab type and rod type targets were studied. As long as the optimized neutron performance is concerned, 1MW solid target is better than mercury target.

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