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Journal Articles

Breakdown of linear spin-wave theory and existence of spinon bound states in the frustrated kagome-lattice antiferromagnet

Mattan, K.*; Ono, Toshio*; Kawamura, Seiko; Nakajima, Kenji; Nambu, Yusuke*; Sato, Taku*

Physical Review B, 105(13), p.134403_1 - 134403_8, 2022/04

 Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)

Spin dynamics of the spin-1/2 kagome-lattice antiferromagnet Cs$$_{2}$$Cu$$_{3}$$SnF$$_{12}$$ was studied using high-resolution, time-of-flight inelastic neutron scattering. The flat mode, a characteristic of the frustrated kagome antiferromagnet, and the low-energy dispersive mode, which is dominated by magnons, can be well described by the linear spin-wave theory. However, the theory fails to describe three weakly dispersive modes between 9 and 14 meV. These modes could be attributed to two-spinon bound states, which decay into free spinons away from the zone center and at a high temperature, giving rise to continuum scattering.

Journal Articles

Summary results of 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))"

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.

Journal Articles

Microscopic analyses on Zr adsorbed IDA chelating resin by PIXE and EXAFS

Arai, Yoichi; Watanabe, So; Ono, Shimpei; Nomura, Kazunori; Nakamura, Fumiya*; Arai, Tsuyoshi*; Seko, Noriaki*; Hoshina, Hiroyuki*; Hagura, Naoto*; Kubota, Toshio*

Nuclear Instruments and Methods in Physics Research B, 477, p.54 - 59, 2020/08

 Times Cited Count:1 Percentile:23.17(Instruments & Instrumentation)

Journal Articles

Quantitative analysis of Zr adsorbed on IDA chelating resin using Micro-PIXE

Arai, Yoichi; Watanabe, So; Ono, Shimpei; Nomura, Kazunori; Nakamura, Fumiya*; Arai, Tsuyoshi*; Seko, Noriaki*; Hoshina, Hiroyuki*; Kubota, Toshio*

QST-M-23; QST Takasaki Annual Report 2018, P. 59, 2020/03

Journal Articles

Quasifree neutron knockout from $$^{54}$$Ca corroborates arising $$N=34$$ neutron magic number

Chen, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Chazono, Yoshiki*; Navr$'a$til, P.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Raimondi, F.*; et al.

Physical Review Letters, 123(14), p.142501_1 - 142501_7, 2019/10

AA2019-0306.pdf:0.57MB

 Times Cited Count:32 Percentile:93.02(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Analysis on adsorbent for spent solvent treatment by micro-PIXE and EXAFS

Arai, Yoichi; Watanabe, So; Ono, Shimpei; Nakamura, Masahiro; Shibata, Atsuhiro; Nakamura, Fumiya*; Arai, Tsuyoshi*; Seko, Noriaki*; Hoshina, Hiroyuki*; Hagura, Naoto*; et al.

International Journal of PIXE, 29(01&02), p.17 - 31, 2019/00

The spent PUREX solvent containing U and Pu is generated from the reprocessing process of spent nuclear fuel. The nuclear material removal is important for the safe storage or disposal of the spent solvent. Our previous study revealed that the adsorbent with the iminodiacetic acid (IDA) functional group is one of the most promising materials for designing the nuclear material recovery process. Accordingly, an IDA-type adsorbent was synthesized by using graft polymerization technology or a chemical reaction to improve the adsorption rate and capacity. The synthesized IDA-type adsorbent was characterized by micro particle-induced X-ray emission (PIXE) and extended X-ray absorption fine structure (EXAFS) analyses. The micro-PIXE analysis revealed that Zr was adsorbed on the whole synthesized adsorbents and quantified the microamount of adsorbed Zr. Moreover, EXAFS suggested that Zr in the aqueous solution and solvent can be trapped by the IDA group with different mechanisms.

Journal Articles

Development of remote pipe welding tool for divertor cassettes in JT-60SA

Hayashi, Takao; Sakurai, Shinji; Sakasai, Akira; Shibanuma, Kiyoshi; Kono, Wataru*; Onawa, Toshio*; Matsukage, Takeshi*

Fusion Engineering and Design, 101, p.180 - 185, 2015/12

 Times Cited Count:2 Percentile:20.43(Nuclear Science & Technology)

Remote pipe welding tool accessing from inside pipe has been newly developed for JT-60SA. Remote handling (RH) system is necessary for the maintenance and repair of in-vessel components such as lower divertor cassettes in JT-60SA. Cooling pipes, which connects between the divertor cassette and the vacuum vessel with bellows are required to be cut and welded in the vacuum vessel by RH system. The available space for RH system is very limited inside the vacuum vessel, especially around the divertor cassettes. Thus, the cooling pipes are required to be cut and weld from the inside in the vacuum vessel. The inner diameter, thickness and material of the cooling pipe are 54.2 mm, 2.8 mm and SUS316L, respectively. An upper pipe connected to the divertor cassette has a jut on the edge to fill the gap between pipes. Owing to the jut and two-times welding, the welding tool achieved the maximum allowable gap of 0.7 mm.

Journal Articles

Operational experience of CW SRF injector and main linac cryomodules at the Compact ERL

Sakai, Hiroshi*; Enami, Kazuhiro*; Furuya, Takaaki*; Kako, Eiji*; Kondo, Yoshinari*; Michizono, Shinichiro*; Miura, Takako*; Qiu, F.*; Sato, Masato*; Shinoe, Kenji*; et al.

Proceedings of 56th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs (ERL 2015) (Internet), p.63 - 66, 2015/12

no abstracts in English

Journal Articles

Science from the initial operation of HRC

Ito, Shinichi*; Yokoo, Tetsuya*; Masuda, Takatsugu*; Yoshizawa, Hideki*; Soda, Minoru*; Ikeda, Yoichi*; Ibuka, Soshi*; Kawana, Daichi*; Sato, Taku*; Nambu, Yusuke*; et al.

JPS Conference Proceedings (Internet), 8, p.034001_1 - 034001_6, 2015/09

Journal Articles

Magnetic structure and electromagnetic properties of LnCrAsO with a ZrCuSiAs-type structure (Ln = La, Ce, Pr, and Nd)

Park, S.-W.*; Mizoguchi, Hiroshi*; Kodama, Katsuaki; Shamoto, Shinichi; Otomo, Toshiya*; Matsuishi, Satoru*; Kamiya, Toshio*; Hosono, Hideo*

Inorganic Chemistry, 52(23), p.13363 - 13368, 2013/12

 Times Cited Count:24 Percentile:77.69(Chemistry, Inorganic & Nuclear)

Journal Articles

Decommissioning program and future plan for Research Hot Laboratory, 2

Koya, Toshio; Nozawa, Yukio; Hanada, Yasushi; Ono, Katsuto; Kanazawa, Hiroyuki; Nihei, Yasuo; Owada, Isao

Dekomisshoningu Giho, (42), p.41 - 48, 2010/09

The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) had been contributed to R&D program for fuels and nuclear materials in or out of JAEA. However, the decommissioning work of RHL has been started on April 2003 as the rationalization program for decrepit facilities in former Tokai institute. This work will be progressing, dismantling the lead cells and decontamination of concrete caves then release in the regulation of controlled area. The partial area of RHL will be used for the central storage of un- irradiated fuel and for temporary storage of radioactive device generated by J-PARC. The 18 lead cells had been dismantled and the preparing work for remained 20 lead cells has been finished including the removal of the applause from the cells, survey of the contamination revel in the lead cells and prediction of radio active waste. The future plan of decommissioning work has been prepared to incarnate the basic vision and dismantling procedure.

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

Antiferromagnetic bipolar semiconductor LaMnPO with ZrCuSiAs-type structure

Yanagi, Hiroshi*; Watanabe, Takumi*; Kodama, Katsuaki; Iikubo, Satoshi*; Shamoto, Shinichi; Kamiya, Toshio*; Hirano, Masahiro*; Hosono, Hideo*

Journal of Applied Physics, 105(9), p.093916_1 - 093916_8, 2009/05

 Times Cited Count:46 Percentile:84.22(Physics, Applied)

Electronic and magnetic properties of a layered compound LaMnPO are examined in relation to a newly discovered iso-structural superconductor LaFeAs(P)O. Neutron diffraction measurements, together with temperature dependent magnetic susceptibility, clarify that LaMnPO is an antiferromagnet at least up to 375 K. The spin moment of a Mn ion is determined to be 2.26 $$mu_{B}$$ at room temperature, and the spin configuration is antiparallel in the Mn-P plane and parallel to between the Mn-P planes, which is rather different from that of LaFeAsO. Optical absorption spectra, photoemission spectra, and temperature dependent electrical conductivity indicate that LaMnPO is a semiconductor. Furthermore, nominally undoped LaMnPO exhibits $$n$$-type conduction while the conduction type is changed by doping of Cu or Ca to the La sites, indicating that LaMnPO is a bipolar conductor. Density functional calculation using the GGA+U approximation supports the above conclusions; the electronic band structure has an open band gap and the antiferromagnetic spin configuration is more stable than the ferromagnetic one.

Journal Articles

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Journal Articles

Improvement of data processing system for advanced diagnostics in JT-60U

Oshima, Takayuki; Kiyono, Kimihiro; Sakata, Shinya; Sato, Minoru; Totsuka, Toshiyuki; Iba, Katsuyuki*; Ozeki, Takahisa; Hirayama, Toshio

Fusion Engineering and Design, 82(5-14), p.1210 - 1215, 2007/10

 Times Cited Count:2 Percentile:19.35(Nuclear Science & Technology)

In JT-60U the data processing system, providing the data acquisition, producing the diagnostic data base, and communicating with the JT-60U control system. The MSP-ISP was replaced by a new Inter-Shot Processor based on the UNIX-OS of a workstation (UNIX-ISP) in 2005. The performance of UNIX-ISP is 2 times as high as that of the MSP-ISP in a stand-alone test using the data conversion program of the CXRS data. Thus we can expect the reduction of the processing time by the optimization of the total sequence. For the remote experiment, we have developed a system called RMSVR with which we can set discharge parameters from the remote site, and thereby the consistency of input parameters is checked. The high security of the remote experiment system is established by the certification and the encrypted communication based on ITBL. A verification test between a university and JAEA Naka indicates that the system using the HTTPS protocol is suitable for the remote experiment.

JAEA Reports

Development of hydrogen production technology using FBR (planning report)

Ono, Kiyoshi; Ohtaki, Akira; Chikazawa, Yoshitaka; Nakagiri, Toshio; ; Sekine, Takashi;

JNC TN9410 2004-013, 76 Pages, 2004/06

JNC-TN9410-2004-013.pdf:7.23MB

This report describes the features of technology, the schedule and the organization for the research and development regarding the hydrogen production technology using FBR thermal energy. Now, the hydrogen production system is proposed as one of new business models for FBR deployment. This system is the production of hydrogen either thermal energy at approximately 500deg-C or electricity produced by a sodium cooled FBR. Hydrogen is expected to be one of the future dean secondary energies without carbon-dioxide emission. Meanwhile the global energy demand will increase, especially in Asian countries, and the energy supply by fossil fuels is not the best choice considering the green house effect and the stability of energy supply. The development of the hydrogen technology using FBR that satisfies "sustainable energy development" and "utilization of energies free from environmental pollution" will be one of the promising options. Based on the above mentioned recognition, we propose the direction of the development, the issues to be solved, the time schedule, the budget, and the organization for R&D of three hydrogen production technologies, the thermochemical hybrid process, the low temperature steam reforming process, and the high temperature steam electrolysis process in JNC.

Journal Articles

Magnetization plateaux of the ${it S}$=1/2 two-dimensional frustrated antiferromagnet Cs$$_{2}$$CuBr$$_{4}$$

Ono, Toshio*; Tanaka, Hidekazu*; Kolomiyets, O.*; Mitamura, Hiroyuki*; Goto, Tsuneaki*; Nakajima, Kenji; Osawa, Akira; Koike, Yoshihiro; Kakurai, Kazuhisa; Klenke, J.*; et al.

Journal of Physics; Condensed Matter, 16(11), p.S773 - S778, 2004/03

 Times Cited Count:58 Percentile:88.73(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Development and test results of a 60kA HTS current lead for fusion application

Isono, Takaaki; Hamada, Kazuya; Kawano, Katsumi; Abe, Kanako*; Nunoya, Yoshihiko; Sugimoto, Makoto; Ando, Toshinari*; Okuno, Kiyoshi; Bono, Takaaki*; Tomioka, Akira*; et al.

Teion Kogaku, 39(3), p.122 - 129, 2004/03

JAERI has been developing a large-capacity high-temperature superconductor (HTS) current lead for fusion application, and succeeded in fabricating and testing a 60kA HTS current lead satisfying ITER requirements. Targets of performance are 1/10 heat leak and 1/3 electric power consumption of cryogenic system compared with a conventional lead. To achieve the target, selection of sheath material of HTS, optimizing the Cu part, reduction of joule heat at joint between HTS and Cu parts, improve of heat transfer between HTS and stainless steel tube. Developed 60kA HTS current lead satisfied the design condition and almost achieved the targets. Adoption of the HTS current lead can reduce 13% electric power consumption of cryogenic system for ITER.

Journal Articles

Test results of 60-kA HTS current lead for fusion application

Isono, Takaaki; Kawano, Katsumi; Hamada, Kazuya; Matsui, Kunihiro; Nunoya, Yoshihiko; Hara, Eiji*; Kato, Takashi; Ando, Toshinari*; Okuno, Kiyoshi; Bono, Takaaki*; et al.

Physica C, 392-396(Part2), p.1219 - 1224, 2003/10

A 60-kA high-temperature-superconductor (HTS) current lead has been fabricated and tested for aiming at the application to a fusion magnet system, providing a low heat leak current lead. The design of HTS current leads is optimized not only to reduce the heat leak but also to perform safe operation even in fault conditions. The HTS current lead consists of a forced flow cooled copper part and a conduction cooled HTS part. The HTS part is composed of 288 Ag-10at.%Au sheathed Bi-2223 tapes and they are cylindrically arrayed on a stainless steel tube. The diameter and the length of the HTS part are 146 mm and 300 mm, respectively. Operation of a 60 kA current, which is the world record, was successfully achieved at coolant of 20 K, 3.2 g/s for the copper part, and a low heat leak of 5.5 W at 4.2 K was demonstrated. This result shows that the electric power of a refrigerator to cool the current lead can be reduced by 1/3 of that in a conventional current lead. In conclusion, technology of a large HTS current lead for fusion application is established.

JAEA Reports

Development of Blow Down Model for the LEAP Code; Validation by Data of Sodium-Water Reaction Tests

Jitsu, Koji; Ono, Isao*; Kawada, Koji; Kurihara, Akikazu; Yatabe, Toshio

JNC TN9400 2003-062, 84 Pages, 2003/06

JNC-TN9400-2003-062.pdf:1.29MB

It is one of the important matters to select the design base leak (DBL) of the steam generator (SG) of a fast breeder reactor (FBR) in sodium-water reaction. The selection of the DBL has an influence on safety, economical efficiency, etc. of the plant.It is necessary to develop the computational model to estimate the sodium-water reaction phenomenon with high accuracy and rationality for selecting the DBL of large SGs. The blow down evaluation on overheating tube failure phenomenon is pointed out as part of the necessary improvements, since the behavior of overheating tube failure is largely affected by the steam conditions inside of the tube.This document shows the validation of blow down model for the LEAP code, which is developed as analysis code for failure propagation of the SG tubes, by test's data in Sodium-Water Reaction Test Rig No.1 (SWAT-1R). The following results have been obtained through the validation.(1) Within the mass flow rate ranging from 160 to 540 g/s in SWAT-1R, it has been confirmed that calculated internal pressure shows good agreement with the test's one. The pressure in tests becomes close to the calculation by Ogasawara model in critical flow models.(2) Mass flow rate is appropriately calculated of the test after about 10 seconds in the beginning of test. Calculated mass flow rate by Ogasawara model is closer to the test than that by Moody model.(3) On both Moody model and Ogasawara model in critical flow models, internal pressure in calculation shows the underestimation of HT-3 test. It will be necessary to investigate this reason.(4) Mass flow rate at the pipe near water heater tank shows the large overshoot in the beginning of test. Also, the small overshoot that supposed to be moved from upper stream appears at the nozzle about 2 seconds. Since these overshoots are estimated too large, these phenomena should require to be examined.(5) As calculated mass flow rate at the nozzle in both critical models have a tendency to be evaluated l

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