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Journal Articles

PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

 Times Cited Count:6 Percentile:52.8(Geosciences, Multidisciplinary)

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Journal Articles

Neutron computed tomography of phase separation structures in solidified Cu-Co alloys and investigation of relationship between the structures and melt convection during solidification

Shoji, Eita*; Isogai, Shosei*; Suzuki, Rikuto*; Kubo, Masaki*; Tsukada, Takao*; Kai, Tetsuya; Shinohara, Takenao; Matsumoto, Yoshihiro*; Fukuyama, Hiroyuki*

Scripta Materialia, 175, p.29 - 32, 2020/01

 Times Cited Count:17 Percentile:79.05(Nanoscience & Nanotechnology)

Journal Articles

Neutron imaging analysis of hydrogen content in pure palladium and aluminum alloys

Shimizu, Kazuyuki*; Hayashida, Hirotoshi*; Toda, Hiroyuki*; Kai, Tetsuya; Matsumoto, Yoshihiro*; Matsumoto, Yoshihisa*

Nihon Kinzoku Gakkai-Shi, 83(11), p.434 - 440, 2019/11

 Times Cited Count:1 Percentile:6.35(Metallurgy & Metallurgical Engineering)

JAEA Reports

Assessment report of research and development activities in FY2014; Activity "Research and development on high-temperature gas-cooled reactor and related hydrogen production technology"

Tatematsu, Kenji; Matsumoto, Hiroyuki

JAEA-Evaluation 2015-001, 91 Pages, 2015/06

JAEA-Evaluation-2015-001.pdf:14.25MB

President of Japan Atomic Energy Agency consulted with the "Evaluation Committee of Research Activities for High-Temperature Gas-Cooled Reactor and Related Hydrogen Production Technology" (hereinafter referred to as "Evaluation Committee"), which consists of specialists in the fields of the evaluation subjects of high-temperature gas-cooled reactor and related hydrogen production technology. The evaluation concludes that an overall judgment is A, because the outcome of the 2nd midterm plan has been obtained as planed in terms of advancing the safety and the practical use in each of the high-temperature gas-cooled reactor technology and the hydrogen production technology. As a result the technological goal has been achieved. Another key outcome obtained is that the achievement for a part of the next midterm plan has been accelerated with the construction of a continuous hydrogen production test facility. In addition, the contents of the 3rd period mid- to long- term plan (draft) are acceptable because they sufficiently reflect the interim report of the high-temperature gas-cooled reactor technical research and development working group organized by the MEXT. This report lists the members of the Evaluation Committee and outlines the method and procedure of the assessment. The results of the assessment by the Evaluation Committee are attached from Page 7.

JAEA Reports

Assessment report of research and development activities; Activity "Research and development on high-temperature gas-cooled reactor and related hydrogen production technology"

Tatematsu, Kenji; Matsumoto, Hiroyuki

JAEA-Evaluation 2014-003, 131 Pages, 2014/09

JAEA-Evaluation-2014-003.pdf:26.08MB

Japan Atomic Energy Agency consulted with "Evaluation Committee of Research Activities for High-Temperature Gas-Cooled Reactor and Related Hydrogen Production Technology" (hereinafter referred to as "Evaluation Committee") which consists of specialists in the fields of the evaluation subjects of high-temperature gas-cooled reactor and related hydrogen production technology. The evaluation concludes that Japan needs to have the high-temperature gas-cooled reactor and hydrogen production technology because it is important that the nuclear energy be utilized to meet heat demand in order to contribute to the emission reduction of carbon dioxide in industry and transportation sectors. Therefore, the research and development should continue with the use of the High Temperature Engineering Test Reactor and the aim of establishing the basic technology. This report lists the members of the Evaluation Committee and the Expert Committee and outlines the method and procedure of the assessment. The result of the assessment by the Committees are attached from page 7.

Journal Articles

Magnetic properties of single crystalline YbFe$$_{2}$$O$$_{4}$$

Yoshii, Kenji; Mizumaki, Masaichiro*; Matsumoto, Keisuke*; Mori, Shigeo*; Endo, Naruki; Saito, Hiroyuki; Matsumura, Daiju; Kambe, Takashi*; Ikeda, Naoshi*

Journal of Physics; Conference Series, 428, p.012032_1 - 012032_5, 2013/04

 Times Cited Count:14 Percentile:96.95

We have investigated a single crystal of multiferroic YbFe$$_{2}$$O$$_{4}$$. Its magnetic transition temperature was 250 K. The magnetization along the c-axis was much larger than that within the ab plane, indicating the Ising character of this system. The field-cooled magnetization became negative below 10 K. This was explained in terms of an antiparallel coupling between Yb and Fe moments. Magnetocaloric effects were also observed. The change of entropy was found to show a broad peak with a width of 100 K, which is favorable to application.

Journal Articles

The Activities for improvement of hot environment in undergrounding pipe-space(trench), 1; The Decrease of the radiant heat from steam pipe

Ishiyama, Toru; Kawasaki, Ichio; Matsumoto, Takenari; Terada, Hideyuki; Kikuchi, Akio; Mizoguchi, Tsuyoshi*; Ikede, Hiroyuki*

Nihon Hozen Gakkai Dai-8-Kai Gakujutsu Koenkai Yoshishu, p.82 - 87, 2011/10

In the undergrounding pipe-space, there are many pipes for utility (electronic cable, water, gas, steam, etc.). These pipes are kept to safe by daily inspection. But hot environment of the pipe-space affects badly the device and a laborer's health. The investigation of the heat distribution was carried on, therefore it was found that the radiant heat around the valve was very much. The method of thermal insulation was examined from the view point of the shape, cost, and effect. Then some of valves were covered with flexible thermal insulation, and the temperature of the area around the covered valves was decreased about 10$$^{circ}$$C.

Journal Articles

Estimation of heat transfer coefficient and flow characteristics on heat transfer tube in sodium-water reaction

Matsumoto, Toshinori*; Takata, Takashi*; Yamaguchi, Akira*; Kurihara, Akikazu; Ohshima, Hiroyuki

Journal of Nuclear Science and Technology, 48(3), p.315 - 321, 2011/03

 Times Cited Count:1 Percentile:10.77(Nuclear Science & Technology)

In the steam generator of a sodium-cooled fast reactor, when the tube fails, water leaks into the sodium stream and sodium-water reaction is initiated. In the present study, a numerical analysis has been carried out to determine the heat transfer coefficient from temperature data obtained in a sodium-water reaction experiment. By updating the heat transfer coefficient, an inverse problem of heat transfer has been solved in the analysis based on the result of the SWAT-1R experiment. It is found that the heat transfer coefficient fluctuates largely during the reaction. The heat transfer coefficient is affected by the flow characteristics. Hence, we characterize the flow pattern near the heat transfer tube at typical periods in the phenomenon progression.

Journal Articles

Photodisintegration of $$^{80}$$Se as a probe of neutron capture for the s-process branch-point nucleus $$^{79}$$

Makinaga, Ayano*; Hohara, Shinya*; Utsunomiya, Hiroaki*; Goko, Shinji*; Kaihori, Takeshi*; Akimune, Hidetoshi*; Yamagata, Tamio*; Goriely, S.*; Toyokawa, Hiroyuki*; Harano, Hideki*; et al.

Proceedings of Science (Internet), 28, p.239_1 - 239_4, 2010/12

no abstracts in English

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

972-MHz RF digital feedback control system for J-PARC linac

Kobayashi, Tetsuya; Michizono, Shinichiro*; Fang, Z.*; Matsumoto, Toshihiro*; Suzuki, Hiroyuki; Yamaguchi, Seiya*; Okada, Yoshihito*

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1068 - 1070, 2010/03

A 972-MHz RF system is being developed for 400-MeV upgrade of the J-PARC linac. The accelerating field stabilities should be less than $$pm$$1% in amplitude and $$pm$$1$$^{circ}$$ in phase. The basic digital LLRF (Low-Level RF) concept is the same as that of the present 324-MHz system with a compact-PCI crate. The main alterations are RF and clock generator (RF&CLK), mixer and I/Q modulator (IQ&Mixer) and digital LLRF algorithm. Since the typical decay time of the new system is faster (because its operational frequency is higher than that of the present 324-MHz cavity), chopped beam compensation is essential. The performance study of the digital feedback system with a cavity simulator is summarized.

Journal Articles

Numerical study on correlation of heat transfer coefficient with void fraction at heat transfer tube surface in sodium water reaction

Matsumoto, Toshinori*; Takata, Takashi*; Yamaguchi, Akira*; Kurihara, Akikazu; Ohshima, Hiroyuki

Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 10 Pages, 2009/09

When a heat transfer tube fails in steam generator (SG) of sodium-cooled fast reactor (SFR), sodium-water reaction (SWR) would take place. It is significant for estimation of the heat transfer from the fluid to the tube wall during SWR region to evaluate the possibility of the secondary tube failure in case of overheating rupture. In the present study, thermal hydraulics simulation of the fluid around the tube is conducted. The heat transfer coefficient is computed, the correlation diagram between the heat transfer coefficient and the void fraction has been obtained. The void fraction around the heat transfer tube in the SWR has been evaluated.

Journal Articles

Photodisintegration of $$^{80}$$Se; Implications for the s-process branching at $$^{79}$$Se

Makinaga, Ayano*; Utsunomiya, Hiroaki*; Goriely, S.*; Kaihori, Takeshi*; Goko, Shinji*; Akimune, Hidetoshi*; Yamagata, Tamio*; Toyokawa, Hiroyuki*; Matsumoto, Tetsuro*; Harano, Hideki*; et al.

Physical Review C, 79(2), p.025801_1 - 025801_8, 2009/02

 Times Cited Count:22 Percentile:79.7(Physics, Nuclear)

Photoneutron cross sections were measured for $$^{80}$$Se immediately above the neutron separation energy with quasimonochromatic $$gamma$$-ray beams to experimentally constrain the E1 $$gamma$$ strength function for $$^{79}$$Se. Two sets of the $$gamma$$ strength function and the level density that equally meet the experimental constraint predict largely different neutron capture cross sections for $$^{79}$$Se. Based on the Maxwell-averaged cross sections of the latest compilation complemented with the predicted cross sections for $$^{79}$$Se, we calculated $$sigma$$N values of the main s-process component using a phenomenological model and deduced empirical abundances of the weak s-process component.

Journal Articles

Interlaboratory comparison of positron annihilation lifetime measurements

Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.

Materials Science Forum, 607, p.248 - 250, 2009/00

So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring the equivalency and reliability of data from different laboratories. As a first, we conducted an interlaboratory comparison of PAL measurements for metal, polymer and silica glass with agreed procedures for data recording and analysis. The PAL data recorded at different laboratories were analyzed with a single lifetime component for the metal sample and with three components for the others, respectively. Based on the results of the reported positron and ortho-positronium lifetimes, the possible sources of the uncertainties in the PAL measurements are discussed. To reduce the effect of scattered $$gamma$$ rays, a lead shield was placed between the detectors. The uncertainty was significantly decreased, signifying that placing lead shields between the detectors effectively reduced the false signals due to the scattered $$gamma$$ rays.

Journal Articles

Estimation of heat transfer coefficient and flow characteristics on heat transfer tube in sodium water reaction

Matsumoto, Toshinori*; Takata, Takashi*; Yamaguchi, Akira*; Kurihara, Akikazu; Ohshima, Hiroyuki

Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 6 Pages, 2008/11

In a steam generator of sodium-cooled fast reactor, high temperature reacting jet is generated when a heat transfer tube fails and it might cause a secondary fauilure of neighboring tubes due to tube deterioration. Quantification of heat transfer from fluid to the tube is important perspective of safety evaluation. In this study, the heat transfer coefficient on the heat transfer tube under sodium-water reaction phenomena was numerically estimated based on the temperature measured in a sodium experiment using SWAT-1R test facility of JAEA. Furthermore, the floa characteristics on the heat transfer tube was investigated taking into account the variation of the heat transfer coefficient.

Journal Articles

Mitigation technologies for damage induced by pressure waves in high-power mercury spallation neutron sources, 2; Bubbling effect to reduce pressure wave

Futakawa, Masatoshi; Kogawa, Hiroyuki; Hasegawa, Shoichi; Naoe, Takashi; Ida, Masato; Haga, Katsuhiro; Wakui, Takashi; Tanaka, Nobuatsu*; Matsumoto, Yoichiro*; Ikeda, Yujiro

Journal of Nuclear Science and Technology, 45(10), p.1041 - 1048, 2008/10

 Times Cited Count:31 Percentile:87.02(Nuclear Science & Technology)

The life time of mercury target will be reduced by the cavitation damage induced by pressure waves. Micro-bubble injection into mercury is one of prospective technologies to mitigate the pressure waves. We have carried out damage tests using mercury loop with an impact generator to evaluate the bubbling effect on the pressure response and cavitation damage. The impulsive pressure was hardly changed but the damage was reduced remarkably by the micro-bubble injection. Numerical simulation was performed to investigate the bubbling effects. It was understandable that micro bubbles suppressed cavitation inception.

Journal Articles

Interlaboratory comparison of positron annihilation lifetime measurements for synthetic fused silica and polycarbonate

Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.

Journal of Applied Physics, 104(2), p.026102_1 - 026102_3, 2008/07

 Times Cited Count:44 Percentile:83.19(Physics, Applied)

Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.

Journal Articles

Cavitation damage prediction for spallation target vessels by assessment of acoustic vibration

Futakawa, Masatoshi; Kogawa, Hiroyuki; Hasegawa, Shoichi; Ikeda, Yujiro; Riemer, B.*; Wendel, M.*; Haines, J.*; Bauer, G.*; Naoe, Takashi; Okita, Kohei*; et al.

Journal of Nuclear Materials, 377(1), p.182 - 188, 2008/06

 Times Cited Count:28 Percentile:85.19(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Photoneutron cross sections for $$^{80}$$Se; Implications for the s-process thermometer

Makinaga, Ayano*; Utsunomiya, Hiroaki*; Kaihori, Takeshi*; Yamagata, Tamio*; Akimune, Hidetoshi*; Goriely, S.*; Toyokawa, Hiroyuki*; Matsumoto, Tetsuro*; Harano, Hideki*; Harada, Hideo; et al.

Nuclear Physics A, 805(1-4), p.564 - 566, 2008/06

Photoneutron cross sections were measured for $$^{80}$$Se near the neutron threshold energy with quasi-monochromatic $$gamma$$ rays. Using the $$^{80}$$Se($$gamma$$,$$n$$) cross section as experimental constraints on the E1 $$gamma$$ strength function, we estimate the neutron capture rates for $$^{79}$$Se. The solar abundance ratio of s-only nuclides $$^{80}$$Kr and $$^{82}$$Kr are analyzed in terms of the s-process branching at $$^{79}$$Se within the local approximation. The corresponding temperature and neutron density regimes are discussed in the light of the s-process scenario in massive stars.

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.

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