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Journal Articles

First demonstration experiment of the neutron rotation method for detecting nuclear material

Komeda, Masao; Toh, Yosuke; Tanabe, Kosuke*; Kitamura, Yasunori*; Misawa, Tsuyoshi*

Annals of Nuclear Energy, 159, p.108300_1 - 108300_8, 2021/09

Journal Articles

Basic experiment for kinetics analysis in sub-critical sate

Kitano, Akihiro; Kishimoto, Yasufumi; Misawa, Tsuyoshi*; Hazama, Taira

KURRI Progress Report 2013, 1 Pages, 2014/10

The approach to criticality is conventionally performed by the inverse multiplication method. The method uses neutron count rate at a steady state attained in a certain waiting time after a reactivity insertion; thus it requires long time (for example, several hours from the startup in Monju reactor). We have developed a more efficient method based on Critical Index (CI) featuring the time behavior of delayed neutrons.

Journal Articles

Accelerator neutron dosimetry using composite-gas-filled proportional counting tube

Usui, Toshihide; Mikami, Satoshi; Hashimoto, Makoto; Nakayama, Naoto; Suzuki, Chihiro*; Tani, Kotaro*; Yamasaki, Keizo*; Misawa, Tsuyoshi*

KURRI Progress Report 2010, P. 209, 2011/10

no abstracts in English

Journal Articles

Development of optical fiber detector for measurement of fast neutron

Yagi, Takahiro*; Misawa, Tsuyoshi*; Pyeon, C. H.*; Unesaki, Hironobu*; Shiroya, Seiji*; Kawaguchi, Shinichi*; Okajima, Shigeaki; Tani, Kazuhiro*

Proceedings of International Conference on the Physics of Reactors, Nuclear Power; A Sustainable Resource (PHYSOR 2008) (CD-ROM), 8 Pages, 2008/09

In order to insert a neutron detector in a narrow space such as a gap of between fuel plates and measure the fast neutrons in real time, a neutron detector with an optical fiber has been developed. This detector consists of an optical fiber whose tip is covered with mixture of neutron converter material and scintillator such as ZnS(Ag). The detector for fast neutrons uses ThO$$_{2}$$ as converter material because $$^{232}$$Th makes fission reaction with fast neutrons. The place where $$^{232}$$Th can be uses is limited by regulations because $$^{232}$$Th is nuclear fuel material. The purpose of this research is to develop a new optical fiber detector to measure fast neutrons without $$^{232}$$Th and to investigate the characteristic of the detector. These detectors were used to measure a D-T neutron generator and fast neutron flux distribution at Fast Critical Assembly. The results showed that the fast neutron flux distribution of the new optical fiber detector with ZnS(Ag) was the same as it of the activation method, and the detector are effective for measurement of fast neutrons.

Journal Articles

On a fast reactor cycle scheme that incorporates a thoria-based minor actinide-containing cermet fuel

Osaka, Masahiko; Takano, Sho*; Yamane, Yoshihiro*; Misawa, Tsuyoshi*

Progress in Nuclear Energy, 50(2-6), p.212 - 218, 2008/03

 Times Cited Count:6 Percentile:43.18(Nuclear Science & Technology)

Concept of fast reactor cycle scheme that incorporates a thoria-based minor actinide-containing cermet fuel is given. The present cermet fuel consists of oxide solid solution of Th and minor actinides and Mo inert matrix. It has been proposed as a high-performance device that can enhance minor actinide transmutation in the fast reactor cycle. It is used in an independent small cycle, whereby dedicated cycle process are adopted. Two-steps process for reprocessing of the present cermet fuel was proposed; it consists of pre-removal of Mo-inert matrix and actinide recovery. A preliminary test for pre-removal of Mo-inert matrix using surrogate cermet fuel was carried out. It was done by dissolution in nitric acid at room temperature. Results showed that Mo-inert matrix was largely dissolved, while oxide remained. Burnup characteristics of a fast reactor core loaded with the cermet fuel were investigated by using neutronic calculation codes. It was revealed that a heterogeneous composition of Mo-inert matrix in inner and outer cores could lead to effective transmutation and flattened power density. It was concluded that the present cermet fuel is potentially a promising one as a high-performance transmutation device for the fast reactor.

Journal Articles

Development of design technology on thermal-hydraulic performance in tight-lattice rod bundle, 3; Numerical estimation on rod bowing effect based on X-ray CT data

Misawa, Takeharu; Onuki, Akira; Mitsutake, Toru*; Katsuyama, Kozo; Misawa, Susumu*; Nagamine, Tsuyoshi; Nakamura, Yasuo; Akimoto, Hajime

Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 8 Pages, 2007/04

Journal Articles

A Novel concept for americium-containing target for use in fast reactors

Osaka, Masahiko; Koi, Mamoru; Takano, Sho*; Yamane, Yoshihiro*; Misawa, Tsuyoshi*

Journal of Nuclear Science and Technology, 43(4), p.367 - 374, 2006/04

 Times Cited Count:12 Percentile:65.95(Nuclear Science & Technology)

The low oxygen potential target, which consist of (Th,Am)Ox dispersed in Mo, as a high performance Am-containing target for fast reactors is proposed. Effects of Mo isotopic ratio on the core characteristics are evaluated with various Mos having different isotopic composition.

JAEA Reports

Rod displacement measurements by X-ray CT and its impact on thermal-hydraulics in tight-lattice rod bundle (Joint research)

Mitsutake, Toru*; Katsuyama, Kozo*; Misawa, Takeharu; Nagamine, Tsuyoshi*; Kureta, Masatoshi*; Matsumoto, Shinichiro*; Akimoto, Hajime

JAERI-Tech 2005-034, 55 Pages, 2005/06

JAERI-Tech-2005-034.pdf:7.76MB

In tight-lattice bundles with about 1mm gap between rods, a rod displacement might affect thermal-hydraulic characteristics. The inside-structure observation of the simulated seven-rod bundle of RMWR was made with the high-energy X-ray CT of JNC. The CT view assured that the rod position was almost the same as expected by design. In the heat transfer experiments, all thermocouples on the center rod showed almost simultaneous BT-induced temperature increase and on the same axial heights showed quite similar time-variation behaviors in the vapor cooling heat transfer regime. It showed that the effect of the geometrical asymmetry was small on the BT characteristics. The calculated critical power by subchannel analysis with the input of the CT measured rod position was smaller by about 5% than that with the designed rod position. It concluded that the error in the calculated critical power was attributable not to the asymmetry in the rod position, but to the models in the subchannel analysis code.

Journal Articles

Rod displacement effect on thermal-hydraulic behaviour in tight-lattice bundle based on X-ray CT measurement

Mitsutake, Toru*; Akimoto, Hajime; Misawa, Takeharu; Kureta, Masatoshi*; Katsuyama, Kozo*; Nagamine, Tsuyoshi*; Matsumoto, Shinichiro*

Proceedings of 4th World Congress on Industrial Process Tomography, Vol.1, p.348 - 353, 2005/00

An inside-structure observation of a tight-lattice 7-rod bundle was made, using the high-energy X-ray computer tomography(CT) apparatus. The two-dimensional configurations of all rods were obtained at seventy-six axial height positions over the whole length of the bundle. The measured results of the rod positions showed small rod position displacements, about 0.5 millimeters at maximum, from the lattice positions. Based on these measured rod position displacement results, the flow area, equivalent hydraulic diameter, rod-rod clearance, and rod-shroud clearance were calculated. The effect of rod position displacement on critical power was estimated by a sub-channel analysis. The result showed that the rod position displacement effect has only a small effect on critical power calculations. The calculated critical power still overestimated the measured value.

JAEA Reports

Experimental study on accelerator driven subcritical reactor, JAERI's nuclear research promotion program, H12-031 (Contract research)

Shiroya, Seiji*; Misawa, Tsuyoshi*; Unesaki, Hironobu*; Ichihara, Chihiro*; Kobayashi, Keiji*; Nakamura, Hiroshi*; Shin, Kazuo*; Imanishi, Nobutsugu*; Kanazawa, Satoshi*; Mori, Takamasa

JAERI-Tech 2004-025, 93 Pages, 2004/03

JAERI-Tech-2004-025.pdf:6.69MB

In view of the future plan of Research Reactor Institute, Kyoto University, the present study consisted of (1) the transmission experiments of high energy neutrons through materials, (2) experimental simulation of ADSR using the Kyoto University Critical Assembly(KUCA), and (3) conceptual neutronics design study on KUR type ADSR using the MCNP-X code. Through the present study, valuable knowledge on the basic nuclear characteristics of ADSR, which is indispensable to promote the study on ADSR, was obtained both theoretically and experimentally. For the realization of ADSR, it is considered to be necessary to accumulate results of research steadily. For this purpose, it is inevitable (1) to compile the more precise nuclear data for the wide energy range, (2) to establish experimental techniques for reactor physics study on ADSR including subcriticality measurement and absolute neutron flux measurement, and (3) to develop neutronics calculation tools which take into account the neutron generation process by the spallation reaction and the delayed neutron behavior.

Oral presentation

Measurement of fuel pin displacement in fuel assembly for fast reactor

Katsuyama, Kozo; Nagamine, Tsuyoshi; Nakamura, Yasuo; Misawa, Susumu*

no journal, , 

no abstracts in English

Oral presentation

Development of design technology on thermal-hydraulic performance in tight-lattice rod bundles, 2; Measurement of rod-bowing effect test assembly by X-ray CT technique

Katsuyama, Kozo; Misawa, Susumu*; Mitsutake, Toru*; Misawa, Takeharu; Nagamine, Tsuyoshi; Nakamura, Yasuo; Onuki, Akira; Akimoto, Hajime

no journal, , 

no abstracts in English

Oral presentation

Irradiation behavior of MA-containing MOX fuel, 5; X-ray CT results of the fuel irradiated for short term (24 hours)

Katsuyama, Kozo; Abe, Kazuyuki; Nagamine, Tsuyoshi; Nakamura, Yasuo; Misawa, Susumu*

no journal, , 

no abstracts in English

Oral presentation

Prototype FBR Monju system start up test "zero power reactor physics test", 5; Applicability of sub-criticality measurement methods

Kitano, Akihiro; Mori, Tetsuya; Nagata, Akito*; Saito, Kosuke; Misawa, Tsuyoshi*; Tamagawa, Yoichi*

no journal, , 

no abstracts in English

Oral presentation

Irradiation behavior of sodium bonded type control rod in the fast reactor, 2; Internal observation result of control elements by X-ray CT

Ishimi, Akihiro; Katsuyama, Kozo; Maeda, Koji; Nagamine, Tsuyoshi; Misawa, Susumu*

no journal, , 

no abstracts in English

Oral presentation

Accelerator neutron dosimetry using composite-gas-filled proportional counting tube

Usui, Toshihide; Mikami, Satoshi; Nakayama, Naoto; Hashimoto, Makoto; Suzuki, Chihiro*; Yamasaki, Keizo*; Misawa, Tsuyoshi*

no journal, , 

no abstracts in English

Oral presentation

Reactivity estimation of KUCA subcritical cores, 1; Kinematic parameter $$beta_{eff}/l$$ estimation using pulsed neutron method

Araki, Shohei; Yamane, Yuichi; Tonoike, Kotaro; Kitamura, Yasunori*; Misawa, Tsuyoshi*

no journal, , 

As a part of the development of a new reactivity estimation method, we carried out an experiment in a subcritical system at the A reactor of the Kyoto University Critical Assembly (KUCA) and estimated the reactivity and the kinematic parameter $$beta_{eff}/l$$.

Oral presentation

Reactivity estimation of KUCA subcritical cores, 2; Estimation based on power profile in quasi-steady state

Yamane, Yuichi; Araki, Shohei; Kitamura, Yasunori*; Misawa, Tsuyoshi*

no journal, , 

A new reactivity estimation method has been developed based on the power profile in quasi-steady state. Several subcritical cores were set up in KUCA A-core and neutron count rate was measured to apply estimation methods for comparison. The values obtained by new method, E, in an near-critical core and calculated value by using MVP code, C, show C/E in the range between 0.9 and 1.5.

18 (Records 1-18 displayed on this page)
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