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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

 Times Cited Count:2 Percentile:32.89(Nuclear Science & Technology)

Journal Articles

Proposal for selective isotope transmutation of long-lived fission products using quasi-monochromatic $$gamma$$-ray beams

Hayakawa, Takehito; Miyamoto, Shuji*; Hajima, Ryoichi; Shizuma, Toshiyuki; Amano, So*; Hashimoto, Satoshi*; Misawa, Tsuyoshi*

Journal of Nuclear Science and Technology, 53(12), p.2064 - 2071, 2016/12

 Times Cited Count:5 Percentile:43.6(Nuclear Science & Technology)

We have proposed a new selective isotope transmutation method using photonuclear reactions with quasi-monochromatic $$gamma$$-ray beams. This method is based on the fact that the particle threshold of a long-lived fission product (LLFP) such as $$^{93}$$Zr, $$^{107}$$Pd, or $$^{79}$$Se is lower than those of stable isotopes of the same chemical element. Therefore, this method has an excellent advantage that LLFPs cannot, in principle, be produced newly even if the target materials include stable isotopes in addition to a LLFP. Laser Compton scattering $$gamma$$-ray sources and neutron capture $$gamma$$-rays in nuclear reactors are candidates for this method.

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:40.16(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

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:63.18(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

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.

Journal Articles

Measurement of flux tilt and eigenvalue separation in axially decoupled core

Ando, Masaki; *; Nishina, Kojiro*; *

Journal of Nuclear Science and Technology, 34(5), p.445 - 453, 1997/05

 Times Cited Count:6 Percentile:48(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Calculation of fine neutron spectrum in irradiation holes in fuel region of JRR-3M

; Nakano, Yoshihiro; Yamane, Yoshihiro*; *;

JAERI-Research 95-059, 83 Pages, 1995/09

JAERI-Research-95-059.pdf:2.24MB

no abstracts in English

Journal Articles

Study on streaming neutron effect through calculation for reaction rate distribution with gold wire at the KUCA

Ando, Masaki; *; *

Annual Reports of the Research Reactor Institute, Kyoto University, 26, p.118 - 124, 1993/00

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

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.

16 (Records 1-16 displayed on this page)
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