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JAEA Reports

Basic study on flow separation phenomenon at the elbow in a large-diameter pipe; Research report in FY2007

Iwamoto, Yukiharu*; Sogo, Motosuke*; Aizawa, Kosuke; Nakanishi, Shigeyuki*; Yamano, Hidemasa

JAEA-Research 2010-009, 58 Pages, 2010/06

JAEA-Research-2010-009.pdf:31.02MB

Experimental studies of the 1/10-scale model of a hot leg piping and their numerical analyses were carried out in order to guarantee the designing of the sodium-cooled fast breeder reactor. The structure of the flow fluctuation was clarified by means of pressure measurements, laser doppler velocimetry (LDV) and flow visualization. LDV measurements were examined for Reynolds number of 50000. FFT analyses of axial velocities indicate that two kinds of flow fluctuations exist in the present elbow. One is the fluctuation with approximate Strouhal number of 1.0 (3.2 Hz) occurring in a shear flow region. The other is with approximate Strouhal number of 0.5 (1.6 Hz) occurring in the separated and its downstream regions. These fluctuations were also observed by flow visualization. The analyses showed that the stream regime was in good agreement with visualization test results.

Journal Articles

Isoscalar giant resonances in the Sn nuclei and implications for the asymmetry term in the nuclear-matter incompressibility

Li, T.*; Garg, U.*; Liu, Y.*; Marks, R.*; Nayak, B. K.*; Madhusudhana Rao, P. V.*; Fujiwara, Mamoru*; Hashimoto, Hisanobu*; Nakanishi, Kosuke*; Okumura, Shun*; et al.

Physical Review C, 81(3), p.034309_1 - 034309_11, 2010/03

 Times Cited Count:92 Percentile:97.51(Physics, Nuclear)

JAEA Reports

Basic study on flow separation phenomenon in cooling system piping in fast reactors; Clarification of complex flow structure in a multi-elbow in a high Reynolds number regime (Joint research report in FY2007)

Yuki, Kazuhisa*; Hashizume, Hidetoshi*; Nakanishi, Shigeyuki*; Aizawa, Kosuke; Yamano, Hidemasa

JAEA-Research 2009-017, 55 Pages, 2009/08

JAEA-Research-2009-017.pdf:16.5MB

At Tohoku University, 1/15 scale and 1/7 scale flow tests are being performed in order to clarify an unsteady flow structure in the cold leg piping and to investigate the scale effect. In FY2007, the 1/15 scale test was carried out using a double elbow geometry. It was confirmed that there existed a separation along the inner wall of the 1st elbow and a large swirling flow in the 2nd elbow. Furthermore, the unsteady flow formed in and/or behind the separation region was transported downstream and flows into the center area of the 2nd elbow. At JAEA, a numerical analytical evaluation method is being developed to evaluate the feasibility of the reactor design. In FY2007, numerical analyses for the 1/15 scale test were performed using the commercial thermal-hydraulics code FLUENT. The analyses showed that the trend of calculated velocity distributions was in good agreement with the visualization test results.

Journal Articles

Study on flow-induced-vibration evaluation of large-diameter pipings in a sodium-cooled fast reactor, 1; Sensitivity analysis of turbulent flow models for unsteady short-elbow pipe flow

Aizawa, Kosuke; Nakanishi, Shigeyuki; Yamano, Hidemasa; Kotake, Shoji; Hayakawa, Satoshi*; Watanabe, Osamu*; Fujimata, Kazuhiro*

Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 7 Pages, 2008/11

To evaluate the flow-induced vibration in the actual-sized pipings of JSFR, computer simulation is necessary. In this study, as the first step, sensitivity analysis of turbulence flow models for unsteady short-elbow pipe flow has been carried out with the STAR-CD thermal-hydraulic simulation code. Through the sensibility analysis, the objective of this study is to propose the best analysis models which can reproduce the unsteady characteristics obtained in the 1/3-scale test results with 9.2 m/s of main flow. In this study, to take into account anisotropic characteristics of turbulence, two turbulent flow models were used: large eddy simulation (LES) and Reynolds stress model (RSM). The both validated simulations have reproduced flow separation region and periodic vortex shedding. The simulation results with both models were compared with power spectrum densities of pressure fluctuations which were used in the pipe vibration evaluation. Only the RSM simulation with the best combination has reproduced the pressure-fluctuation power spectrum densities, which were characterized by a peak frequency of 10 Hz in the 1/3 test with 9.2 m/s.

Journal Articles

Half-life of $$^{184}$$Re populated by the $$(gamma,n)$$ reaction from laser Compton scattering $$gamma$$ rays at the electron storage ring NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

Physical Review C, 74(6), p.065802_1 - 065802_5, 2006/12

 Times Cited Count:23 Percentile:79.56(Physics, Nuclear)

We report a half-life of the ground state of $$^{184}$$Re populated by the $$^{185}$$Re$$(gamma,n)$$$$^{184}$$Re reaction with the laser Compton scattering $$gamma$$-rays generated through relativistic engineering. The $$gamma$$-rays are provided at the electron storage ring NewSUBARU. The previous experiment using deuteron-induced reactions has yielded a recommended half-life of the 3$$^-$$ ground state of $$^{184}$$Re to be 38.0 $$pm$$ 0.5 d, including a possible contribution from the 8$$^{+}$$ isomer ($$T_{1/2}$$ = 169 $$pm$$ 8 d) of $$^{184}$$Re since the presence of the isomer was not known at that time. In contrast, the $$(gamma,n)$$ reaction has an advantage to selectively populate the ground state because this reaction does not bring large angular momentum. The measured half-life of 35.4 $$pm$$ 0.7 d is shorter than the previous half-life by about 7%. This difference is crucial for applications using the activation method.

Journal Articles

Tuning of dissociative-adsorption processes on Cu{1 0 0} by controlling the kinetic energy of the impinging O$$_{2}$$ molecule

Okada, Michio*; Moritani, Kosuke; Yoshigoe, Akitaka; Teraoka, Yuden; Nakanishi, Hiroshi*; Di$~n$o, W. A.*; Kasai, Hideaki*; Kasai, Toshio*

Chemical Physics, 301(2-3), p.315 - 320, 2004/06

 Times Cited Count:14 Percentile:43.58(Chemistry, Physical)

O$$_{2}$$ molecules adsorb dissociatively on Cu{1 0 0} surfaces to form the oxygen-saturated surface with the coverage of 0.5 ML. It has been found that the oxidation has proceeded more than 0.5 ML by using 2.3-eV-O$$_{2}$$ molecular beams. The kinetics of the adsorption reaction was the first order. This reveals that the collision-induced adsorption results in the adsorption of only one oxygen atom. On the other hand, the reaction kinetics showed the second order in the case of 0.6-eV-O$$_{2}$$ incidence. This implies that tentative molecular adsorption takes place in such low collision energy case.

Journal Articles

Excitation and decay of the isovector spin-flip giant monopole resonance via the $$^{208}$$Pb($$^{3}$$He,${it tp}$) reaction at 410 MeV

Zegers, R. G. T.*; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal$`e$s, S.*; Hara, Keigo*; et al.

Nuclear Physics A, 731, p.121 - 128, 2004/02

 Times Cited Count:11 Percentile:58.28(Physics, Nuclear)

no abstracts in English

Journal Articles

t+$$^{3}$$He molecular structures in $$^{6}$$Li studied ($$^{3}$$He,$$alpha$$) reaction at 450 MeV

Nakayama, Shintaro*; Yamagata, Tamio*; Akimune, Hidetoshi*; Fujiwara, Mamoru; Fushimi, Kenichi*; Greenfield, M. B.*; Hara, Keigo*; Hara, Kaoru*; Hashimoto, Hisanobu*; Ichihara, Kayoko*; et al.

Nuclear Physics A, 731, p.355 - 362, 2004/02

 Times Cited Count:0 Percentile:0.01(Physics, Nuclear)

no abstracts in English

Journal Articles

Microscopic structure of the Gamow-Teller resonance in $$^{58}$$Cu

Hara, Keigo*; Adachi, Takeshi*; Akimune, Hidetoshi*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Fushimi, Kenichi*; Hara, Kaoru*; Harakeh, M. N.*; et al.

Physical Review C, 68(6), p.064612_1 - 064612_9, 2003/12

 Times Cited Count:11 Percentile:59.58(Physics, Nuclear)

no abstracts in English

Journal Articles

Excitation and decay of the Isovector giant monopole resonances via the $$^{208}$$Pb($$^{3}$$He,${it tp}$) reaction at 410 MeV

Zegers, R. G. T.; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal$`e$s, S.*; Hara, Keigo*; et al.

Physical Review Letters, 90(20), p.202501_1 - 202501_4, 2003/05

 Times Cited Count:46 Percentile:85.12(Physics, Multidisciplinary)

no abstracts in English

Oral presentation

Nuclear photoreaction on Re isotopes by Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

no journal, , 

no abstracts in English

Oral presentation

Half-life of $$^{184}$$Re populated by photodisintegration reaction with Laser Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

no journal, , 

no abstracts in English

Oral presentation

Half-life measurements of neutron-deficient isotopes using laser Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, Sho*; Horikawa, Ken*; Hayashi, Yukio; Kawase, Keigo; Kando, Masaki; Kikuzawa, Nobuhiro; Chiba, Satoshi; et al.

no journal, , 

no abstracts in English

13 (Records 1-13 displayed on this page)
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