Study of hydraulic behavior for reactor upper plenum in sodium-cooled fast reactor; Verification analysis of water experiment and applicability of vortex prediction method

Fujii, Tadashi; Chikazawa, Yoshitaka; Konomura, Mamoru; Kamide, Hideki; Kimura, Nobuyuki; Nakayama, Okatsu; Ohshima, Hiroyuki; Narita, Hitoshi*; Fujimata, Kazuhiro*; Itooka, Satoshi*

JAEA-Research 2006-017, 113 Pages, 2006/03

JAEA-Research-2006-017.pdf:14.98MB

A conceptual design study of the sodium-cooled fast reactor is in progress in the Feasibility Study on Commercialized Fast Reactor Cycle Systems. Reduced scale water experiments are being performed in order to clarify the flow pattern in the upper plenum of the reactor which has higher velocity condition than the past design. In this report, the hydraulic analyses of the water experiments using the general-purpose thermal hydraulic analysis program were executed; and the applicability to evaluation of flow pattern and vortex cavitations for the designed reactor was examined. (1) Steady-state analyses under the Froude number similar condition were carried out for the 1/10th reduced scale plenum experiments. Analyses results reproduced the characteristic flow patterns in the upper plenum, such as gushed flow from the inside of the upper internal structure to reactor vessel wall and the jet flow from the slit of the upper internal structure. Further, it was confirmed that the calculated flow pattern of a designed reactor system agreed with that of the water experiment qualitatively. Moreover, the influence which setting of numerical solution and boundary condition etc. in analyzing causes to flow pattern in the plenum became clear. (2) The distribution of the vortices under the dipped plate region in the 1/10th plenum model was evaluated using the prediction method of a submerged vortex which is based on the stretching vortex theory. In case of the same velocity condition as the reactor, it identified the two vortices which were sucked into the hot leg piping from the cold leg piping wall as the submerged vortex cavitations. From this analysis result, it confirmed that the submerged vortex cavitations, which may occur in the reactor upper plenum steadily, could be identified using this prediction method.

t+He molecular structures in Li studied (He,) 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

https://doi.org/10.1016/j.nuclphysa.2003.11.048

no abstracts in English

Excitation and decay of the Isovector giant monopole resonances via the Pb(He,) 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; Gals, S.*; Hara, Keigo*; et al.

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

https://doi.org/10.1103/PhysRevLett.90.202501

no abstracts in English

Study on microbial influence assessment in geological disposal

Fukunaga, Sakae*; Nakayama, Mamoru*; Jintoku, Takashi*; *; Kudo, Akira*

JNC TJ8400 2002-036, 186 Pages, 2002/02

JNC-TJ8400-2002-036.pdf:1.34MB

We conducted the following four investigations concerned with microbial influence in geological disposal facilities. (1)Improvement of the FEP dictionary and investigation on chemical evolution of nitrate by microbes. (2)Experimental estimation of microbial mobility in compacted Na bentonite saturated by synthetic seawater with 30wt% silica sand and Ca bentonite with 30wt% silica sand. (Both dry densities are 1.6 g/cm.) (3)Habitation of microbes in Na rich bentonite deposit and Ca rich one. (4)Interaction between SRB (sulfate reducing bacteria) and Np in a reducing environment at Eh=-85mV. As the result, it was revealed that (1)microbial activity in near field rock and microbial denitrification of nitrate under the existence of electron donor are important, (2)microbes didn't move in Na bentonite in 3 weeks and moved to the distance of 20mm in Ca bentonite, and (3)microoragnisms existed at the inside of the deposits. (4)The difference between distribution coefficient of Eh=-85mV and Eh=-500mV was evaluated.

Soft dipole resonance in the neutron-skin nucleus He

Nakayama, Shintaro*; Yamagata, Tamio*; Akimune, Hidetoshi*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Fushimi, Kenichi*; Inomata, Toru*; Kori, Hideki*; et al.

Physical Review Letters, 85(2), p.262 - 265, 2000/07

https://doi.org/10.1103/PhysRevLett.85.262

no abstracts in English