Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Okita, Shoichiro; Tasaki, Seiji*; Abe, Yutaka*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 19(3), p.178 - 184, 2020/09
The Kyoto University Accelerator-based Neutron Source (KUANS) is a compact neutron source that is mainly used for spectrometer and detector development. In addition, it is also suited for experiments to study the neutronic design of moderators owing to the relatively low neutron generation yield by 
Be(p,n). We present a neutronic design of the neutron moderator on a reentrant-hole configuration for KUANS to enhance the neutron emission, and some experiments are conducted at KUANS for verification. A polyethylene moderator on a reentrant-hole configuration is designed by PHITS calculation and is introduced to KUANS to obtain intense oblong neutron beams. The intensity of the pulsed neutron beam is experimentally measured. The results reveal that the intensity becomes approximately 1.9 times stronger than that of the conventional rectangular design. In addition, the ratio of its intensity to the conventional intensity increases to approximately threefold as the neutron wavelength increases. It is interesting to note that the longer the neutron wavelength, the more efficiently they are extracted from the inside of the moderator owing to the existence of the reentrant-hole configuration.
Niizeki, Tomohiko*; Kikkawa, Takashi*; Uchida, Kenichi*; Oka, Mineto*; Suzuki, Kazuya*; Yanagihara, Hideto*; Kita, Eiji*; Saito, Eiji
AIP Advances (Internet), 5(5), p.053603_1 - 053603_6, 2015/05
Times Cited Count：39 Percentile：81.57(Nanoscience & Nanotechnology)Iwata, Keiji*; Imafuku, Muneyuki*; Suzuki, Kanki*; Shobu, Takahisa; Orihara, Hideto*; Sakai, Yusuke*; Akita, Koichi; Oya, Shinichi*; Ishiyama, Kazushi*
Journal of Applied Physics, 117(17), p.17A910_1 - 17A910_4, 2015/03
Times Cited Count：6 Percentile：27.03(Physics, Applied)Internal stress distribution for generating closure domains occurring in laser-irradiated Fe-3%Si(110) steels was investigated using high-energy X-ray analysis and domain theory based on the variational principle. The measured triaxial stresses inside the specimen were compressive and the stress in the rolling direction became more dominant than stresses in the other directions. The calculations based on the variational principle of magnetic energy for closure domains showed that the measured triaxial stresses made the closure domains more stable than the basic domain without closure domains. The experimental and calculation results reveal that the laser-introduced internal stresses result in the occurrence of the closure domains.
Sumita, Junya; Fujita, Ichiro; Shibata, Taiju; Makita, Taiyo*; Takagi, Takashi*; Kunimoto, Eiji*; Sawa, Kazuhiro; Kim, W. J.*; Park, J. Y.*
IOP Conference Series; Materials Science and Engineering, 18(16), p.162010_1 - 162010_4, 2011/09
Times Cited Count：1 Percentile：52.78(Materials Science, Ceramics)For control rod element of Very High Temperature Reactor, carbon fiber reinforced carbon matrix composite (C/C composite) is one of the major candidate materials for its high strength and thermal stability. Since the crack propagation of the C/C composite is complicated, the fracture behavior is one of the most important subjects of the design methodology for the control rod with the C/C composite. In this study, in order to assess the Mode-II fracture behavior of the two-dimensional (2D-) C/C composite which has the layer structure of laminas composed of fibers and matrix, bending test with oxidized end notched flexure specimen was carried out. The interlaminar fracture toughness decreased with increasing the oxidation for the 2D-C/C composite. The oxidized matrix causes reduction of fracture toughness and the reduction ratio is dependent on the matrix type. The crack initiates at the boundary between fiber bundles and grows along them without breaking the fiber. It is thought that the cracks which were initiated at the interface between matrix and fiber were gathered into the voids in the boundary between fiber bundles, and then the crack grows up in the matrix.
Shibata, Taiju; Sumita, Junya; Makita, Taiyo*; Takagi, Takashi*; Kunimoto, Eiji*; Sawa, Kazuhiro; Kim, W. J.*; Jung, C. H.*; Park, J. Y.*
Nihon Kikai Gakkai Rombunshu, A, 76(764), p.383 - 385, 2010/04
no abstracts in English
Shibata, Taiju; Sumita, Junya; Makita, Taiyo*; Takagi, Takashi*; Kunimoto, Eiji; Sawa, Kazuhiro
Ceramics in Nuclear Applications, Vol.30, Issue 10, p.19 - 32, 2009/11
Japan Atomic Energy Agency (JAEA) carries out R&Ds for Very High Temperature Reactor (VHTR). Since the core components in VHTR will be used at severer condition than in the High Temperature Engineering Test Reactor (HTTR), it is important to develop heat-resistant ceramic composite. C/C and SiC/SiC composites are major candidates substitute for metallic control rod. JAEA studies on the application of the composite materials for the VHTR control rod following the scheme; (1) Database establishment, (2) Design and (3) Demonstration test by HTTR. In this paper, the development plan was explained. It was expressed that the irradiation effects on graphitized C/C composite showed similar trend with that of graphite. It is possible to evaluate the irradiation effects based on the existing graphite irradiation database. The HTTR can irradiate large component. It is possible to demonstrate the structural integrity of the mock-up of the composite control rod being necessary for the final phase.
Takagi, Takashi*; Makita, Taiyo*; Kunimoto, Eiji; Shibata, Taiju; Sawa, Kazuhiro
JAEA-Technology 2008-094, 22 Pages, 2009/03
JAEA-Technology-2008-094.pdf:5.49MB
To advance the performance and safety of High Temperature Gas-cooled Reactors (HTGRs), it is expected to use heat-resistant materials substitute for metallic materials in the core internal structural components of HTGRs at higher temperature. Carbon fiber reinforced carbon-carbon composite (C/C composite) is one of candidates as heat-resistant materials, and investigations are under going to apply the core internal structural components such as the control rod for the Very High Temperature Reactor (VHTR). This report describes the experimental results of irradiation effects on dimensional change, coefficient of thermal expansion and elastic modulus obtained by PIE (Post-Irradiation Examinations) for C/C composite irradiated in 03M-47AS capsule at the Japan Materials Testing Reactor (JMTR).
crystalsAbe, Kenichiro*; Miyoshi, Yoshihiro*; Ashida, Atsushi*; Wakita, Kazuki*; Oshima, Takeshi; Morishita, Norio; Kamiya, Tomihiro; Watase, Seiji*; Izaki, Masanobu*
Japanese Journal of Applied Physics, 44(1B), p.718 - 721, 2005/01
Times Cited Count：1 Percentile：4.7(Physics, Applied)no abstracts in English
O
Hata, Yoshiaki; Kita, Eiji*; Kagomiya, Isao*; Kay, Kohn*; Shiratori, Kiichi*; Nakajima, Kenji*; Kakurai, Kazuhisa*
Journal of the Physical Society of Japan, Vol.70, Supplement A, p.195 - 196, 2001/05
no abstracts in English
crystalsMurakami, Go*; Abe, Kenichiro*; Ashida, Atsushi*; Wakita, Kazuki*; Watase, Seiji*; Izaki, Masanobu*; Oshima, Takeshi; Morishita, Norio; Ito, Hisayoshi
no journal, ,
no abstracts in English
O in magnetic fieldsKatano, Susumu; Tsunoda, Yorihiko*; Suzuki, Hiroyuki*; Shiratori, Kiichi*; Kay, Kohn*; Kita, Eiji*
no journal, ,
no abstracts in English
Sakai, Yusuke*; Akita, Koichi*; Oya, Shinichi*; Sueyoshi, Kazuyuki*; Shobu, Takahisa; Imafuku, Muneyuki*; Suzuki, Kanki*; Iwata, Keiji*
no journal, ,
no abstracts in English
Shibata, Taiju; Makita, Taiyo*; Takagi, Takashi*; Kunimoto, Eiji; Sawa, Kazuhiro
no journal, ,
no abstracts in English
Hata, Katsuro; Suzuki, Kazuyuki; Miyoshi, Ryuta; Sugai, Eiji; Hikita, Keiichi; Nakamura, Yoshinobu; Hayashi, Shinichiro
no journal, ,
The pulse filter of the clarification process used the sintered metal powder filter at Tokai reprocessing plant. It is known that the sintered metal powder filter is easy to be clogged up by sludge. Therefore, we examined the filtration performance of the sintered laminated wire mesh filter which might substitute for the sintered metal powder filter.
Shibata, Taiju; Sumita, Junya; Makita, Taiyo*; Takagi, Takashi*; Kunimoto, Eiji; Sawa, Kazuhiro; Park, Y.*; Kim, W. J.*; Jung, C. H.*
no journal, ,
no abstracts in English
Sugai, Eiji; Terunuma, Hirotaka; Otani, Takehisa; Hikita, Keiichi; Hatanaka, Akira; Samoto, Hirotaka; Okano, Masanori; Hayashi, Shinichiro
no journal, ,
A dissolution test of the sludge gathered from the dissolver of Tokai Reprocessing Plant (TRP) was performed for the purpose of eliminating of the sludge, which deposited in the dissolver and clogged pipes equipped in the dissolver. In the result, the sludge consisted primarily of ZrMoO
(OH)(HO) and was possible to eliminate at the rate of about 80% by using NaOH and HNO
reagent which was commonly-used in the PUREX process. From this experimental result, it is thought that the method of using NaOH and HNO reagent is effective method for the elimination of the sludge which deposited in the dissolver.
Shibata, Taiju; Makita, Taiyo*; Sumita, Junya; Takagi, Takashi*; Fujita, Ichiro; Kunimoto, Eiji*; Sawa, Kazuhiro
no journal, ,
no abstracts in English
Kikuchi, Hideki; Suzuki, Kazuyuki; Sugai, Eiji; Hikita, Keiichi; Otani, Takehisa; Samoto, Hirotaka; Hayashi, Shinichiro
no journal, ,
About 6t the Fugen MOX type B fuels, whose Pu content rate is about 1.7%, were reprocessed on Tokai Reprosessing Plant(TRP) to the present. It was required to control plutonium(Pu) concentration of dissolution liquor because of the higher Pu content of the MOX fuels. There operational method to control Pu concentration by dilution has be established. And the amount of Pu, which was transferred to the highly radioactive liquid waste system with the residue from the clarification process, was investigated.
Okita, Takafumi*; Suzuki, Sachiko*; Hoashi, Eiji*; Sugiura, Hirokazu*; Kanemura, Takuji; Kondo, Hiroo; Yamaoka, Nobuo*; Horiike, Hiroshi*
no journal, ,
In the International Fusion Materials Irradiation Facility (IFMIF), a stable lithium (Li) target is required to maintain the integrity of the Li target itself and guarantee the desired neutron flux level. In this study, amplitudes of the free-surface waves were measured in an Osaka University Li loop with a contact-type liquid level sensor, and based on the measurement results, heat deposition rate from the deuteron beam to the flow channel (back wall) was calculated. Measurement results showed that at 175 mm downstream from the nozzle exit, maximum amplitudes at the velocity of more than 9 m/s were approximately 2 mm, which is larger than the IFMIF design specification value of 1 mm. However occurrence frequency of such large-amplitude waves were very low. Based on the amplitude measurement data, heat deposition rate from the deuteron beam to the flow channel was calculated to be less than 200 W in the simple model.
Oka, Takeshi*; Hoashi, Eiji*; Suzuki, Sachiko*; Takita, Masahiro*; Kanemura, Takuji; Kondo, Hiroo; Furukawa, Tomohiro; Yamaoka, Nobuo*; Horiike, Hiroshi*
no journal, ,
In the International Fusion Materials Irradiation Facility (IFMIF), a lithium (Li) jet produced by a nozzle is designed as a deuteron-beam target to generate neutrons. To maintain integrity of the Li target, amplitude of surface waves on the jet is designed to be less than 1 mm. In this study, a numerical simulation with a CFD code was conducted to examine a boundary layer flow along the nozzle wall which directly affects generation of the surface waves. Calculation results with Large-Eddy Simulation (LES) model showed that Goertler vortices were generated along the wall near the nozzle exit. After flow separation at the nozzle exit, the generated Goertler vortices did not disappear underneath the free surface. This suggests the vortices affects generation of the surface waves near the nozzle exit.
