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Journal Articles

Spallation and fragmentation cross sections for 168 MeV/nucleon $$^{136}$$Xe ions on proton, deuteron, and carbon targets

Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.

Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06

 Times Cited Count:4 Percentile:55.1(Physics, Nuclear)

The spallation and fragmentation reactions of $$^{136}$$Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.

Journal Articles

High-resolution Compton cameras based on Si/CdTe double-sided strip detectors

Odaka, Hirokazu*; Ichinohe, Yuto*; Takeda, Shinichiro*; Fukuyama, Taro*; Hagino, Koichi*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; Watanabe, Shin*; Kokubun, Motohide*; et al.

Nuclear Instruments and Methods in Physics Research A, 695, p.179 - 183, 2012/12

 Times Cited Count:20 Percentile:83.8(Instruments & Instrumentation)

We have developed a new Si/CdTe semiconductor double-sided strip detector (DSD) Compton camera. The camera consists of a 500-$$mu$$m-thick Si-DSD and four layers of 750-$$mu$$m-thick CdTe-DSDs all of which have common electrode configuration segmented into 128 strips on each side with pitches of 250$$mu$$m. In order to realize high angular resolution and to reduce size of the detector system, a stack of DSDs with short stack pitches of 4 mm is utilized to make the camera. Taking advantage of the excellent energy and position resolutions of the semiconductor devices, the camera achieves high angular resolutions of 4.5 degrees at 356 keV and 3.5 degrees at 662 keV. To obtain such high resolutions together with an acceptable detection efficiency, we demonstrate data reduction methods including energy calibration using Compton scattering continuum and depth sensing in the CdTe-DSD. We also discuss imaging capability of the camera and show simultaneous multi-energy imaging.

Journal Articles

Applications and imaging techniques of a Si/CdTe Compton $$gamma$$-ray camera

Takeda, Shinichiro*; Ichinohe, Yuto*; Hagino, Koichi*; Odaka, Hirokazu*; Yuasa, Takayuki*; Ishikawa, Shinnosuke*; Fukuyama, Taro*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; et al.

Physics Procedia, 37, p.859 - 866, 2012/10

 Times Cited Count:19 Percentile:98.35

By using new Compton camera consisting of silicon double-sided strip detector (Si-DSD) and CdTe-DSD developed for the ASTRO-H mission, an experiment was conducted to study its feasibility for advanced hotspot monitoring. In addition to hotspot imaging already provided by commercial imaging systems, the identification of the variety of radioisotopes is realized thanks to the good energy resolution given by the semiconductor detectors. Three radioisotopes of $$^{133}$$Ba (356 keV), $$^{22}$$Na (511 keV) and $$^{137}$$Cs (662 keV) were individually imaged by applying event selection in the energy window and the $$gamma$$-ray images was correctly overlapped by an optical picture. The detection efficiency of 1.68$$times$$10$$^{-4}$$ (effective area: 1.7$$times$$10$$^{-4}$$ cm$$^2$$) and angular resolution of 3.8$$^{circ}$$ were obtained by stacking five detector modules for 662 keV $$gamma$$-ray. The higher detection efficiency required in a specific use can be achieved by stacking more detector modules.

Journal Articles

Applications of $$^{3}$$He neutron spin filters on the small-angle neutron scattering spectrometer SANS-J-II

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Aizawa, Kazuya; Arai, Masatoshi; Noda, Yohei; et al.

Journal of Physics; Conference Series, 294(1), p.012017_1 - 012017_7, 2011/06

 Times Cited Count:2 Percentile:67.18

Journal Articles

Structure of glasses for $$^{3}$$He neutron spin filter cells

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Suzuya, Kentaro; Aizawa, Kazuya; Arai, Masatoshi; et al.

Journal of Physics; Conference Series, 294(1), p.012004_1 - 012004_7, 2011/06

 Times Cited Count:2 Percentile:67.18

Journal Articles

Research on glass cells for $$^{3}$$He neutron spin filters

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Suzuya, Kentaro; Aizawa, Kazuya; Arai, Masatoshi; et al.

Physica B; Condensed Matter, 406(12), p.2443 - 2447, 2011/06

Journal Articles

Research on glass cells for $$^{3}$$He neutron spin filters

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Suzuya, Kentaro; Aizawa, Kazuya; Arai, Masatoshi; et al.

Physica B; Condensed Matter, 406(12), p.2443 - 2447, 2011/06

 Times Cited Count:3 Percentile:17.28(Physics, Condensed Matter)

Journal Articles

Characterization of glasses for $$^{3}$$He neutron spin filter cells

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Suzuya, Kentaro; Arai, Masatoshi; Takeda, Masayasu; et al.

Nuclear Instruments and Methods in Physics Research A, 634(1, Suppl.), p.S122 - S125, 2011/04

JAEA Reports

Study on uncertainties of glass dissolution rate in safety assessment for a geological disposal of high level radioactive waste (Contract research)

Sekioka, Yasushi*; Takeda, Seiji; Kimura, Hideo

JAEA-Research 2009-062, 68 Pages, 2010/03

JAEA-Research-2009-062.pdf:3.62MB

In safety assessment for geological disposal, release of radionuclides from vitrified waste is dependent on dissolution rate of glass matrix. It is assumed that the alteration and dissolution of glass in an engineered barrier system proceeds by a mechanism not related by the chemical affinity for dissolution reaction of glass matrix. Recent studies indicate that the glass dissolution rate is likely to decrease as time passed, but scientific basis on the dissolution process has not been necessarily understood. We estimate uncertainty of the glass dissolution rate represented by not only a model of constant dissolution rate but also a model of decreasing dissolution rate. In order to estimate the parameter uncertainty of the glass dissolution rate, we carried out the statistical analysis of the appropriate release rate data of boron for a hypothetical condition of disposal system, based on investigating the relation between published data of glass dissolution and those experimental conditions. As a result of the model of constant dissolution rate, the uncertainty of the glass dissolution rate is estimated to be a variance with about 3 orders and logarithmic mean of 0.004 g/m$$^{2}$$/day. The glass dissolution rate by the decreasing model changes in the range of 10$$^{-5}$$ to 10$$^{-4}$$ g/m$$^{2}$$/day by 1000 years and is lower than the minimum value estimated by the model of constant dissolution rate. The result indicates that the difference of two models may lead to large variance of the glass dissolution rate in safety assessment.

JAEA Reports

Study on applicability of low alkaline cement in Horonobe Underground Research Laboratory Project, 2 (Contract research)

Nakayama, Masashi; Kobayashi, Yasushi; Matsuda, Takeshi*; Noda, Masaru*; Iriya, Keishiro*; Takeda, Nobufumi*

JAEA-Research 2009-035, 70 Pages, 2009/11

JAEA-Research-2009-035.pdf:11.27MB

In Horonobe Underground Research Center construction of underground facility began in 2005 and construction practicality test with HFSC (Highly Fly-ash contained Silica-fume Cement) is planned in a part of the gallery. Before HFSC will be placed in the gallery it is necessary to validate that HFSC has performance under the actual construction. The research results in 2007 were as follows. As corrosion behavior in HFSC, reinforced concrete specimen with HFSC 226 have been exposed to off-shore condition at in saline water and splashed zone and analyzed corrosion rate and chloride intrusion, and they were summarized. Service life time of HFSC reinforced concrete was assessed more than 50 years until cracking due to corrosion is generated. pH and components of solid and liquid phase which were made in 2002, and stored in water were analyzed. And cement paste of shotcrete which are made in 2006 were also analyzed. In this pH of shotcrete is lower than other in situ concrete since accelerating agent may act as decreasing factor of pH. The results obtained from this ten year's study were summarized on shotcerete, in situ concrete and grouting. Based on the summery, method of quality control, such as testing method, frequency, and standards so on, were investigated.

JAEA Reports

Assessment on long-term safety for geological disposal of high level radioactive waste; Application of probabilistic safety assessment methodology to uncertainties in hypothetical geological disposal system (Contract research)

Takeda, Seiji; Yamaguchi, Tetsuji; Nagasawa, Hirokazu; Watanabe, Masatoshi; Sekioka, Yasushi; Kanzaki, Yutaka; Sasaki, Toshihisa; Ochiai, Toru; Munakata, Masahiro; Tanaka, Tadao; et al.

JAEA-Research 2009-034, 239 Pages, 2009/11

JAEA-Research-2009-034.pdf:33.52MB

In safety assessment for geological disposal of high level radioactive waste, it is of consequence to estimate the uncertainties due to the long-term frame associated with long-lived radionuclides and the expanded geological environment. The uncertainties result from heterogeneity intrinsic to engineered and natural barrier materials, insufficient understanding of phenomena occurring in the disposal system, erroneous method of measurement, and incomplete construction. It is possible to quantify or to reduce the uncertainties according to scientific and technological progress. We applied a deterministic and a Monte Carlo-based probabilistic method simulation techniques to the uncertainty analysis for performance of hypothetical geological disposal system for high level radioactive waste. This study provides the method to evaluate the effects of the uncertainties with respect to scenarios, models and parameters in engineering barrier system on radiological consequence. The results also help us to specify prioritized models and parameters to be further studied for long-term safety assessment.

Journal Articles

Durability evalation of steel reinforced low alkaline concrete using pozzolanic reaction based on exposure test in off-shore

Takeda, Nobufumi*; Kuwae, Hitomi*; Nakayama, Masashi; Kobayashi, Yasushi

Konkurito Kogaku Nenji Rombunshu (DVD-ROM), 31(1), p.895 - 900, 2009/07

High level radioactive waste repository will be constructed using a variety of concrete such as shotcrete, lining for rock support. It is anticipated that highly alkaline plume released from the cement hydrates could influence the long-term performance of barrier system as a result of degradation of the buffer material and rock. In order to reduce hyper alkaline, JAEA is now undertaking development of low alkaline cement (HFSC: Highly Fly ash contained Silicafume Cement). In this report, to evaluate corrosion behavior of reinforcement in HFSC, we have conducted exposure test using reinforced concrete specimens in off-shore condition for 6 years, investigated corrosion rate and permeation chloride ion in concrete. As the result, it is evaluated that the period until crack occurred is more than 30 years in case of using HFSC concrete.

Journal Articles

Development of the 4S and related technologies, 7; Summary of the FCA XXIII experiment analyses towards evaluation of prediction accuracies for the 4S core characteristics

Ueda, Nobuyuki*; Fukushima, Masahiro; Okajima, Shigeaki; Takeda, Toshikazu*; Kitada, Takanori*; Nauchi, Yasushi*; Kinoshita, Izumi*; Matsumura, Tetsuo*

Proceedings of 2009 International Congress on Advances in Nuclear Power Plants (ICAPP '09) (CD-ROM), p.9493_1 - 9493_9, 2009/05

A series of critical experiments were carried out in the JAEA fast critical facility (FCA) named FCA XXIII cores with placing emphases on the reflector reactivity worth and the sodium void reactivity which are especially important from the view point of safety features of the 4S. The analyses of those physics mockup experiments have been carried out by the neutron transport calculation methods with continuous energy Monte Carlo code MVP and 70 energy-group discrete ordinate P0-S8 transport code DANTSYS using libraries processed from JENDL-3.3 data file. The results showed that combination of the stochastic and deterministic transport calculation methods (Monte Carlo and Sn) provided good prediction bases for criticality, reflector worth, sodium void reactivity, reaction rate ratios and absorber reactivity worth for the 4S nuclear design.

Journal Articles

Velocity vector profile measurement using multiple ultrasonic transducers

Obayashi, Hironari; Tasaka, Yuji*; Kon, Seiji*; Takeda, Yasushi*

Flow Measurement and Instrumentation, 19(3-4), p.189 - 195, 2008/06

 Times Cited Count:11 Percentile:50.68(Engineering, Mechanical)

This paper proposes a new technique that enables the measurement of the velocity vector in multi-dimensions on a line of the flow field. A system to achieve this goal was developed based on ultrasonic velocity profiling by using multiple transducers. A two-dimensional system was constructed and successfully applied to an actual flow field for two-dimensional velocity vector measurements. To estimate the influence of existence of a wall, acoustic field under the developed system was calculated by solving two-dimensional wave equation and then the focal point of an ultrasonic beam was determined to optimize the system. The system was applied to measure two directional velocity components of a periodic velocity fluctuation in a wake of a cylinder as an example of unsteady flow. Temporal variation of velocity vector profiles well represent the velocity fluctuation, and vorticity distribution, which is obtained from the spatial distribution of velocity vector, well represents vertical motion in the wake.

Journal Articles

Measurement of liquid metal flow by using ultrasonic velocity profiling

Tasaka, Yuji*; Takeda, Yasushi*; Obayashi, Hironari; Yanagisawa, Takatoshi*

Choompa Techno, 18(6), p.70 - 74, 2006/11

Ultrasonic Velocity Profiler (UVP) enables us to obtain the velocity profiles in liquid metals. It is obvious that any optical method of flow measurement cannot be applied since all the liquid metals are opaque. This meant that non-invasive flow measurement was not possible until the ultrasonic measurement has been established. In this short review, we explain the various measurement relut given by UVP.

Journal Articles

Visualization of liquid metal flow by ultrasound Doppler method

Obayashi, Hironari; Tasaka, Yuji*; Takeda, Yasushi*

Kashika Joho Gakkai-Shi, 26(103), p.252 - 257, 2006/10

Ultrasonic velocity profiler (UVP) has been established in fluid mechanics and fluid engineering applications of flow measurement. It is utmost importance to investigate flow structure and behavior of liquid metals when it is used in an active manner not only in heat transportation but also a flowing medium, as is the case for any kinds of situations of fluid flow is involved, and as such, fluid mechanics is applied. It is obvious that any optical method of flow measurement cannot be applied since all the liquid metals are opaque. This meant that non-invasive flow measurement was not possible until the ultrasonic measurement has been established. In the past studies, UVP has been applied to the flow measurement of liquid metal. In this paper, we show some examples which measured the liquid metal flow and introduce a new measurement system based on the UVP techniques.

Journal Articles

Measurement of LBE flow velocity profile by UDVP

Kikuchi, Kenji; Takeda, Yasushi*; Obayashi, Hiroo*; Tezuka, Masao*; Sato, Hiroshi

Journal of Nuclear Materials, 356(1-3), p.273 - 279, 2006/09

 Times Cited Count:9 Percentile:55.03(Materials Science, Multidisciplinary)

Measurements of LBE flow velocity profile were realized in the spallation target model by the ultrasonic Doppler velocity profile technique. Hitherto, it has not yet been done well because both of poor wetting property of LBE with stainless steels and poor performance of supersonic probes at high temperatures. Measurement was made for a return flow in the target model, which has coaxially arranged annular and tube channels. The electromagnetic pump generates LBE flow and the flow rate was measured by the electromagnetic flow meter. Measurement results show that re-circulation occurred near the surface of beam window, which might affect a heat transfer of target container.

Journal Articles

Development of velocity vector profile measurement system by using ultrasound

Obayashi, Hironari; Yamaguchi, Kohei*; Kon, Seiji*; Takeda, Yasushi*

Nihon Ryutai Rikigakkai Nenkai 2006 Koen Rombunshu (CD-ROM), 4 Pages, 2006/09

The velocity vector of fluid is expressed with the function of the velocity components of three directions, and the function of time. Therefore, in order to understand the flow structure, it becomes very important to measure these components. We propose the new equipment that enables three-dimensional velocity vector measurement of the flow field of the name of Vector-UVP. It consists of a central emitter, symmetrically surrounded by three receivers. If the plane transducer is used for the emitter, the ultrasonic beam will spread in the practical range, consequently measurement volume will become too large. Thus, the characteristic of the ultrasonic beam from the emitter has great influence on the performance of Vector-UVP. For the solution of this problem, and in order to simplify our equipment, we use commercial focused transducer for the emitter. We developed 2D Vecotor-UVP system. And this system successfully applied to an actual flow field for two-dimensional velocity vector measurements.

Journal Articles

Surface decoration of stainless steel for LBE flow measurement by ultrasonic techniques

Kikuchi, Kenji; Tezuka, Masao*; Saito, Shigeru; Oigawa, Hiroyuki; Takeda, Yasushi*

Proceedings of 4th International Symposium on Ultrasonic Doppler Method for Fluid Mechanics and Fluid Engineering (ISUD-4), p.107 - 110, 2004/09

When the steel is submerged into LBE, LBE will contact with the steel except for the interface among LBE, gas and metal where the surface energy controls the shape of the free surface in LBE. It is supposed that LBE will transmit ultrasonic wave into LBE through the contacting area. However, the ultrasonic echo was too low to detect from the steel container filled with LBE. The measurement was improved by coating the interface between the steel and LBE with the SnPb solder. After an immersion test the steel surface was covered with thin LBE layer. The thickness of the layer is only 10 to 20 micron m. So it will not disturb the flow pattern where UVP is applied. Sn was not detected by X ray analyses. This is an evidence how the steel was wetted in LBE and how the ultrasonic wave transmitted though the interface of LBE and the steel.

Journal Articles

None

Takei, H.; Takeda, Yasushi; Omura, Akiko

Hoshasen, 27(1), p.41 - 52, 2001/00

None

49 (Records 1-20 displayed on this page)