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Koyama, Shinichi; Nakagiri, Toshio; Osaka, Masahiko; Yoshida, Hiroyuki; Kurata, Masaki; Ikeuchi, Hirotomo; Maeda, Koji; Sasaki, Shinji; Onishi, Takashi; Takano, Masahide; et al.
Hairo, Osensui Taisaku jigyo jimukyoku Homu Peji (Internet), 144 Pages, 2021/08
JAEA performed the subsidy program for the "Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Development of Technologies for Enhanced Analysis Accuracy and Thermal Behavior Estimation of Fuel Debris))" in 2020JFY. This presentation summarized briefly the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning and Contaminated Water Management.
Shamoto, Shinichi; Ito, Takashi; Onishi, Hiroaki; Yamauchi, Hiroki; Inamura, Yasuhiro; Matsuura, Masato*; Akatsu, Mitsuhiro*; Kodama, Katsuaki; Nakao, Akiko*; Moyoshi, Taketo*; et al.
Physical Review B, 97(5), p.054429_1 - 054429_9, 2018/02
Times Cited Count：18 Percentile：65.6(Materials Science, Multidisciplinary)Nuclear and magnetic structure and full magnon dispersions of yttrium iron garnet Y
Fe
O
have been studied by neutron scattering. The lowest-energy dispersion below 14 meV exhibits a quadratic dispersion as expected from ferromagnetic magnons. The imaginary part of 
-integrated dynamical spin susceptibility 
"(
) exhibits a square-root energy-dependence in the low energies. The magnon density of state is estimated from the "() obtained on an absolute scale. The value is consistent with a single chirality mode for the magnon branch expected theoretically.
Araki, Yuki*; Sato, Hisao*; Okumura, Masahiko; Onishi, Hiroshi*
Surface Science, 665, p.32 - 36, 2017/11
Times Cited Count：11 Percentile：48.83(Chemistry, Physical)no abstracts in English
Naito, Fujio*; Anami, Shozo*; Ikegami, Kiyoshi*; Uota, Masahiko*; Ouchi, Toshikatsu*; Onishi, Takahiro*; Oba, Toshiyuki*; Obina, Takashi*; Kawamura, Masato*; Kumada, Hiroaki*; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1244 - 1246, 2016/11
The proton linac installed in the Ibaraki Neutron Medical Research Center is used for production of the intense neutron flux for the Boron Neutron Capture Therapy (BNCT). The linac consists of the 3-MeV RFQ and the 8-MeV DTL. Design average beam current is 10mA. Target is made of Beryllium. First neutron production from the Beryllium target was observed at the end of 2015 with the low intensity beam as a demonstration. After the observation of neutron production, a lot of improvement s was carried out in order to increase the proton beam intensity for the real beam commissioning. The beam commissioning has been started on May 2016. The status of the commissioning is summarized in this report.
Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masaaki; Oda, Yoshihiro; Saito, Tatsuo; Kato, Tomoko; Niizato, Tadafumi; Iijima, Kazuki; Sato, Haruo; Yui, Mikazu; et al.
Nuclear Science and Engineering, 179(1), p.104 - 118, 2015/01
Times Cited Count：8 Percentile：56.13(Nuclear Science & Technology)The prediction of the distribution and fate of radioactive materials eventually deposited at surface in the Fukushima area is one of the main objectives and expected to be achieved in an efficient manner. In order to make such prediction, a number of mathematical models of radioactive contaminants, with particular attention on cesium, on the land and in rivers, lakes, and estuaries in the Fukushima area are developed. Simulation results are examined with the field investigations simultaneously implemented. The basic studies of the adsorption/absorption mechanism of cesium and soils have been performed to shed light on estimating distribution coefficient between dissolved contaminant and particulate contaminant.
-wave one-neutron halo configuration on 
MgKobayashi, Nobuyuki*; Nakamura, Takashi*; Kondo, Yosuke*; Tostevin, J. A.*; Utsuno, Yutaka; Aoi, Nori*; Baba, Hidetada*; Barthelemy, R.*; Famiano, M. A.*; Fukuda, Naoki*; et al.
Physical Review Letters, 112(24), p.242501_1 - 242501_5, 2014/06
Times Cited Count：89 Percentile：94.33(Physics, Multidisciplinary)no abstracts in English
-wave halos at the drip-line; 
NeNakamura, Takashi*; Kobayashi, Nobuyuki*; Kondo, Yosuke*; Sato, Yoshiteru*; Tostevin, J. A.*; Utsuno, Yutaka; Aoi, Nori*; Baba, Hidetada*; Fukuda, Naoki*; Gibelin, J.*; et al.
Physical Review Letters, 112(14), p.142501_1 - 142501_5, 2014/04
Times Cited Count：62 Percentile：91.13(Physics, Multidisciplinary)no abstracts in English
Takasaki, Koji; Yasumune, Takashi; Onishi, Takashi; Nakamura, Keisuke; Ishimi, Akihiro; Ito, Chikara; Osaka, Masahiko; Ono, Masashi*; Hatakeyama, Shuichi*; Takahashi, Hiroyuki*; et al.
JAEA-Research 2013-043, 33 Pages, 2014/01
JAEA-Research-2013-043.pdf:13.81MB
In the Fukushima Daiichi Nuclear Power Plant, it is assumed that the core fuels melted partially or wholly, and the normal technique of accounting for a fuel assembly is not applicable. Therefore, it is necessary to develop the transparent and rational technique of accounting in the process of collection and storage of fuel debris. In this research, an application of the superconducting phase Transition Edge Sensor microcalorimeter (TES microcalorimeter) is studied for the accounting of nuclear materials in the fuel debris. It is expected that the detailed information of nuclear materials and fission products in fuel debris is obtained by using a high-resolution characteristic of TES microcalorimeter. In this report, the principle of TES microcalorimeter, the measurement experiment using TES in JAEA, and the simulated calculation using the EGS5 code system are summarized.
Am content on homogenization of denatured Pu with broad range of neutron energy based on U irradiation test in the experimental fast reactor JoyoShiba, Tomooki*; Sagara, Hiroshi*; Onishi, Takashi; Koyama, Shinichi; Maeda, Shigetaka; Han, C. Y.*; Saito, Masaki*
Annals of Nuclear Energy, 51, p.74 - 80, 2013/01
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The design consideration of DU-Am oxide fuel pin was performed for Pu denaturing in the framework of the protected plutonium production based on the irradiation analyses of the depleted U (DU) samples irradiated in the environment of broad range of neutron energy in the experimental fast reactor Joyo. From the results of irradiation analyses of DU, it was confirmed that there is a strong dependence of transmutation behavior of DU on the resonance neutron ratio even in a fast reactor. Also, it was confirmed that there is a strong effect of sample material form and shape on generated Pu nuclide inventory especially near the reflector area (
20% resonance neutron ratio), because of the intensive self-shielding of 
U, though less is expected for Am. Sensitivity study of hypothetical DU-Am oxide fuel pellet irradiation on neutron energy and burn-up was performed to evaluate significant gradient of radial Pu isotopic composition profile (e.g., from 12 to 18% distribution in 3% Am doping, in 30% resonance neutron ratio and in 4.0
10
[n/cm
] of neutron fluence inside a large pellet with softened neutron spectrum), and vulnerability of the fuel pellet surface in terms of Pu denaturing was revealed. Design consideration of radial zoning of Am content was introduced to flatten the radial distribution of isotopic composition of Pu. The results of radial zoning of Am (4% and 3% of Am in the outer and inner zone of DU-Am oxide fuel pellet) in hypothetical irradiation neutronics analysis showed the radial profile of produced Pu is over 15 at.% of Pu isotopic composition in any zone and meets the criteria of Kimura et al. based on decay heat of Pu to impede utilization to fission explosive devices.
Matsumoto, Koji*; Sagara, Hiroshi*; Han, C. Y.*; Onishi, Takashi; Saito, Masaki*; Yamauchi, Ippei*
Transactions of the American Nuclear Society, 107(1), p.1018 - 1019, 2012/11
Protected plutonium production (P
) with a high proliferation-resistance was proposed by increasing the Pu ratio in the total plutonium through minor actinides (MAs) doping into the fresh blanket fuel. Moderator effect on P was evaluated. As a result, the transmutation ratio is larger with the heterogeneous moderator than with the homogeneous one, and the isotopic ratio of Pu was increased.
Onishi, Takashi; Koyama, Shinichi; Shiba, Tomooki*; Sagara, Hiroshi*; Saito, Masaki*
Progress in Nuclear Energy, 57, p.125 - 129, 2012/05
Times Cited Count：1 Percentile：10.14(Nuclear Science & Technology)In order to develop blanket fuel with high proliferation resistance in fast breeder reactor, chemical analysis of nine U samples irradiated in experimental fast reactor Joyo and Pu contents and Pu isotopic composition of the samples were measured. As results, dependence of Pu production behavior from U on neutron spectra was revealed.
Osaka, Masahiko; Donomae, Takako; Ichikawa, Shoichi; Sasaki, Shinji; Ishimi, Akihiro; Inoue, Toshihiko; Sekio, Yoshihiro; Miwa, Shuhei; Onishi, Takashi; Asaka, Takeo; et al.
Proceedings of 1st Asian Nuclear Fuel Conference (ANFC), 2 Pages, 2012/03
Support system for training and education of future expert in hot laboratories of Oarai-JAEA, named FEETS, is presented. The system has been established based on research results on both characterization of Oarai hot laboratory and user-needs. Various programs under FEETS are also introduced.
Seki, Yohji; Onishi, Yoichi*; Yoshikawa, Akira; Tanigawa, Hisashi; Hirose, Takanori; Ozu, Akira; Ezato, Koichiro; Tsuru, Daigo; Suzuki, Satoshi; Yokoyama, Kenji; et al.
Progress in Nuclear Science and Technology (Internet), 2, p.139 - 142, 2011/10
R&D of a test blanket module (TBM) with a water-cooled solid breeder has been performed for ITER. For our design, the temperature of a coolant pressurized up to 15 MPa is designed as 598 K in an outlet of the TBM, respectively. Establishment of estimation methods of the flow phenomena is important for designs of the channel network and predictions of the material corrosion and erosion. A purpose of our research is to establish and verify the method for the prediction of the flow phenomena. The Large-eddy simulation and Reynolds averaged Navier-Stokes simulation have been performed to predict the pressure drop and flow rates in the channels of the side wall. It results the inhomogeneous flow rates in each channel. At viewpoint of the heat removal capability, however, the smallest flow-rates near the first wall are evaluated with satisfying acceptance criteria. Moreover, the results of the numerical simulation correspond with those of experiment performed for the real size mock-up.
Kondo, Keitaro; Ochiai, Kentaro; Tatebe, Yosuke; Yagi, Takahiro; Onishi, Seiki; Takakura, Kosuke; Sato, Satoshi; Konno, Chikara
Progress in Nuclear Science and Technology (Internet), 1, p.61 - 64, 2011/02
At the Fusion Neutronics Source (FNS) facility of JAEA we have conducted various integral experiments with DT neutrons for fusion reactor materials and have made a significant progress in the verification of their nuclear data. Recently we started a new series of integral experiments with DD neutrons at FNS in order to verify nuclear data relating to DD neutrons effectively. An integral experiment on beryllium with the DD neutron source will be presented in this conference. A beryllium pseudo-cylinder assembly of 45 cm in thickness and 63 cm in the diameter was built at the distance of 20 cm from the DD neutron source, and reaction rates of the 
In(n,n')
In, 
Au(n,
)
Au and 
Li(n,
)T reactions and a 
U fission rate were measured. The measured values were compared with calculations with the MCNP5 code and the latest nuclear data libraries; JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1. A slight disagreement between the measurement and the calculation was found in the reaction rate of In, which is sensitive to neutrons above 0.3 MeV. We identified that the disagreement originated from the angular differential cross section data of the elastic scattering around 3 MeV and from the (n,2n) reaction cross section data near its threshold energy. The calculated reaction rates of Au, Li and U, which are sensitive to low energy neutrons, showed a large overestimation, which also appeared at the beryllium integral experiment with DT neutrons previously carried out at FNS. This problem has not been solved yet.
Ochiai, Kentaro; Tatebe, Yosuke; Kondo, Keitaro; Onishi, Seiki; Sato, Satoshi; Takakura, Kosuke; Konno, Chikara
Progress in Nuclear Science and Technology (Internet), 1, p.142 - 145, 2011/02
Nuclear performances of the ITER Test Blanket Module (TBM) can be calculated with a neutron transport code and nuclear data library. Neutron flux spectra in the TBM should be measured in order to validate the calculated nuclear performances of the TBM. The multi-foil activation method (MFAM) is considered to be one of the most prospective candidates for the neutron flux spectrum measurement. We have examined to measure neutron flux spectra in TBM simulating assemblies with a DT neutron source by using MFAM. We deduced neutron flux spectra in the simulated assemblies with a Monte Carlo code MCNP4C, some nuclear data and unfolding code NEUPAC. The results indicated that the adjusted neutron flux was reasonable for fast neutrons and that measured reaction rate data of more (n,) reactions were necessary for more adequate adjustment for slow neutrons.
TiO
/Be assembly with DT neutronsKondo, Keitaro; Tatebe, Yosuke; Ochiai, Kentaro; Sato, Satoshi; Takakura, Kosuke; Onishi, Seiki; Konno, Chikara
Fusion Engineering and Design, 85(7-9), p.1229 - 1233, 2010/12
Times Cited Count：8 Percentile：49.46(Nuclear Science & Technology)In the previous blanket neutronics experiments conducted at the FNS facility of Japan Atomic Energy Agency, the following disagreements between experiments and analyses have been pointed out: (1) In the experiment with a Li-enriched LiTiO layer and a beryllium layer, approximately 10% overestimation was found for the tritium production rate (TPR) when a neutron reflector composed of SS316 was attached. (2) In the experiment with natural LiO pebbles sandwiched by beryllium layers, TPR was overestimated near the rear beryllium layer by up to 10%. In order to confirm the above problems clearly, a new blanket neutronics experiment using a natural LiTiO layer and beryllium layers with DT neutrons was conducted at FNS. TPR distributions inside the LiTiO layer were measured with LiCO pellets with and without the source reflector. The measured TPR well agreed with the calculation within an estimated experimental error of 6% in the both experiments. The influence of the reflector was not remarkable in the present experiment. Contrary to our expectation, no remarkable difference was observed in the TPR distribution around the rear beryllium layer.
Seki, Yohji; Onishi, Yoichi*; Yoshikawa, Akira; Tanigawa, Hisashi; Hirose, Takanori; Ozu, Akira; Ezato, Koichiro; Tsuru, Daigo; Suzuki, Satoshi; Yokoyama, Kenji; et al.
Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 4 Pages, 2010/10
R&D of a test blanket module (TBM) with a water-cooled solid breeder has been performed for ITER. For our design, the temperature of a coolant pressurized up to 15 MPa is designed as 598 K in an outlet of the TBM, respectively. Establishment of estimation methods of the flow phenomena is important for designs of the channel network and predictions of the material corrosion and erosion. A purpose of our research is to establish and verify the method for the prediction of the flow phenomena. The Large-eddy simulation and Reynolds averaged Navier-Stokes simulation have been performed to predict the pressure drop and flow rates in the channels of the side wall. It results the inhomogeneous flow rates in each channel. At viewpoint of the heat removal capability, however, the smallest flow-rates near the first wall are evaluated with satisfying acceptance criteria. Moreover, the results of the numerical simulation correspond with those of experiment performed for the real size mockup.
NeNakamura, Takashi*; Kobayashi, Nobuyuki*; Kondo, Yosuke*; Sato, Yoshiteru*; Aoi, Nori*; Baba, Hidetada*; Deguchi, Shigeki*; Fukuda, Naoki*; Gibelin, J.*; Inabe, Naoto*; et al.
Physical Review Letters, 103(26), p.262501_1 - 262501_4, 2009/12
Times Cited Count：198 Percentile：97.53(Physics, Multidisciplinary)no abstracts in English
Sato, Satoshi; Takakura, Kosuke; Ochiai, Kentaro; Kondo, Keitaro; Tatebe, Yosuke; Onishi, Seiki; Wada, Masayuki*; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; et al.
Fusion Science and Technology, 56(1), p.227 - 231, 2009/07
Times Cited Count：1 Percentile：10.22(Nuclear Science & Technology)Previously DT neutronics experiments were performed by using partial blanket mockups for Japanese ITER test blanket module at JAEA FNS, and tritium production rates (TPR) inside blanket mockups were measured in details. The calculation with the nuclear data library FENDL-2.1 and Monte Carlo code MCNP4C agreed well with most of the measured TPRs within uncertainty of 10%. On the other hand, overestimations were found for the TPR in the experiment with a reflector and the TPR around the boundary between the rear part of the breeder layer and the beryllium layer by more than 10%. In order to confirm this concern, we measured reaction rate distribution in the partial blanket mockups with DT neutrons with two solid breeder blanket partial mockups, (Be/LiTiO/Be, SS316/LiTiO/SS316). Experiments were performed with and without a neutron source reflector. In order to measure reaction rate distributions, the activation foil method was applied using Nb and Au foils in this study. Experimental analyses were performed by MCNP4C with FENDL-2.1. Calculation results to experimental ones (C/Es) on the Au reaction rate with a reflector were larger than those without one. Detailed results are presented in this conference.
Yagi, Toshiaki; Morita, Yosuke; Kawakami, Waichiro; *; *; *; *
EIM-90-124, p.65 - 74, 1990/12
no abstracts in English
