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Yamamoto, Tomohiko; Kato, Atsushi; Hayakawa, Masato; Shimoyama, Kazuhito; Ara, Kuniaki; Hatakeyama, Nozomu*; Yamauchi, Kanau*; Eda, Yuhei*; Yui, Masahiro*
Proceedings of 2023 International Congress on Advanced in Nuclear Power Plants (ICAPP 2023) (Internet), 6 Pages, 2023/04
Takeda, Takeshi; Otsu, Iwao
Mechanical Engineering Journal (Internet), 2(5), p.15-00132_1 - 15-00132_15, 2015/10
Takeda, Takeshi; Onuki, Akira*; Nishi, Hiroaki*
Journal of Energy and Power Engineering, 9(5), p.426 - 442, 2015/05
Enuma, Yasuhiro; Kawasaki, Nobuchika; Orita, Junichi*; Eto, Masao*; Miyagawa, Takayuki*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05
In the frame work of generation IV international forum, safety design criteria and safety design guideline for the generation IV sodium-cooled fast reactors have been developing. JAEA, JAPC, MFBR have been investigating design study for JSFR to satisfy SDC. In addition to the safety measures, maintainability, reparability and manufacturability are taken into account in the JSFR design study. This paper describes the design of main components. Enlargement of the access route for the inspection devices and addition of the access routes were carried out for the reactor structure. The pump-integrated IHX was modified for the primary heat exchanger, which was installed for the decay heat removal in the IHX at the upper plenum, to be removable for improved repair and maintenance. For the steam generator, protective wall tube type design is under investigation as an option with less R&D risks.
Takeda, Takeshi; Onuki, Akira*; Nishi, Hiroaki*
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 13 Pages, 2014/12
Susyadi; Yonomoto, Taisuke
JAERI-Research 2005-011, 64 Pages, 2005/06
JAERI-Research-2005-011.pdf:2.57MB
Steady-state natural circulation (NC) in the PWR was investigated focusing on non uniform flow among steam generator (SG) U-tubes observed in the ROSA/LSTF experiments. In the analysis using the RELAP5/MOD3 code, the SG behavior was analyzed using the partial SG model with one, five, or nine parallel flow paths in the primary side and boundary conditions based on the experiments. The results showed that simulations using the model with five or nine tubes were capable to capture important non uniform phenomena such as reverse flow, fill and dump and stagnant vertical stratification, and the stable SG outlet flow as observed in the experiments. Heat transfer rates to the secondary side were, however, underpredicted by up to 15%. Furthermore, difficulties were found in establishing the steady state condition especially for the low pressure analysis: only when the inlet flow rate was carefully imposed, stable NC behavior was obtained.
LiF scintillating and MSGC neutron detectors in JAERINakamura, Tatsuya; Katagiri, Masaki; Yamagishi, Hideshi; Tanaka, Hiroki; Sakasai, Kaoru; Soyama, Kazuhiko
Hamon, 15(1), p.67 - 73, 2005/01
Development of scintillating and gaseous neutron detectors in Japan Atomic Energy Research Institute is briefly described. In this paper, the performances of the developed 2-d neutron detectors, concerning ZnS/LiF scintillating detectors with wavelength shifting fiber read-out and micro-strip gas chambers with individual read-out, are presented.
Yamagishi, Hideshi; Nakamura, Tatsuya; Soyama, Kazuhiko; Masaoka, Sei; Aizawa, Kazuya
Review of Scientific Instruments, 75(7), p.2340 - 2345, 2004/07
Times Cited Count：9 Percentile：44.72(Instruments & Instrumentation)A new instrument system with the capability of secondary-particle discrimination (InSPaD) was studied for the development of two-dimensional neutron detectors (2D-ND) filled with helium-3 gas and with high spatial resolution. The InSPaD can discriminate between the tracks of a proton and a triton created in the nuclear reaction 
He(
,
)
by simply setting the level of discriminators appropriately in each signal channel, and the system exhibits a high spatial resolution, high counting rate, low background, and stability. The simulations of the 2D-ND equipped with the InSPaD revealed spatial resolutions of 0.46 mm in full width at half maximum for a 10% mixture of C
H
with helium-3 at 0.3 MPa. The results of neutron-detection experiments using a microstrip gas chamber, including the range of the secondary particles and the pulse-height distribution, agreed well with the simulated results, indicating the feasibility of the InSPaD.
The Working Team for Examination Operation of Samples From Core Shroud at Fukushima Dai-ni Unit-3
JAERI-Tech 2004-044, 92 Pages, 2004/05
JAERI-Tech-2004-044.pdf:15.18MB
The present examination has been performed with the objective to ensure the transparency of the examination as the third-party organization by providing technical basis for identifying the causes of cracking through examination of the sample taken from the cracked region of outer H6a welding portion of the core shroud at Fukushima Dai-ni Nuclear Power Station Unit-3, which was a part of sample stored in the Nippon Nuclear Fuel Development Co., Ltd. in the examination of Tokyo Electric Power Company in 2001. The present examination of the sample was conducted at the post irradiation examination facilities of JAERI. The following findings were obtained from the result of the present examination. (1)Three cracks were observed at the portion 3 to 9mm apart from the weld metal and the maximum depth was about 8mm. (2)Intergranular cracking was observed in almost whole fracture surface. The transgranular cracking was partially observed within the depth of about 300
m from the surface. (3)Hardening layer over Hv400 at its maximum was found from the surface to the depth of about 500m. Based on the examination results concerning presence of tensile residual stress by welding and relatively high dissolved oxygen contents in core coolant, it is concluded that the cracks were mainly initiated in the hardening layer by transgranular stress corrosion cracking and propagated along the grain boundaries.
Pb(He,
) reaction at 410 MeVZegers, R. G. T.*; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal
s, S.*; Hara, Keigo*; et al.
Nuclear Physics A, 731, p.121 - 128, 2004/02
Times Cited Count：11 Percentile：55.75(Physics, Nuclear)no abstracts in English
Hidaka, Akihide; Maruyama, Yu; Nakamura, Hideo
Proceedings of 6th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operations and Safety (NUTHOS-6) (CD-ROM), 15 Pages, 2004/00
Severe accident studies showed that Direct Containment Heating issue was resolved for PWRs because a creep rupture at pressurizer surge line would occur prior to the melt-through of Reactor Pressure Vessel during station blackout (TMLB'). However, it was recently concerned that, if the secondary system is depressurized during TMLB', the creep rupture at SG U-tubes would occur earlier than the surge line. This pressure- and temperature-induced SG U-tube rupture (PTI-SGTR) is not preferable because of the increase in offsite consequences. The SCDAP/RELAP5 analyses by USNRC showed that the surge line would fail earlier than the U-tubes. However, the analyses used a coarse nodilization for steam mixing at the SG inlet plenum that could affect the temperature of U-tubes. To investigate the effect of steam mixing, an analysis was performed with MELCOR1.8.4. The analysis showed that the surge line would fail earliest during TMLB' while the U-tubes could fail earliest during TMLB' with secondary system depressurization. Further investigation is needed for occurrence conditions of PTI-SGTR.
Seul, K. W.*; Yonomoto, Taisuke; Bang, Y. S.*; Anoda, Yoshinari
Proceedings of 6th Biennial Conference on Engineering Systems Design and Analysis (ESDA2002), 9 Pages, 2002/07
no abstracts in English
Kondratyev, V. N.
Physical Review Letters, 88(22), p.221101_1 - 221101_4, 2002/06
Times Cited Count：44 Percentile：81.90(Physics, Multidisciplinary)The neutron star crust magnetodynamics is demonstrated to exhibit erraticjumps at the fields corresponding to the sharp change of nuclide magneticmoments induced by quantization effects. Such a noise originates frommagnetic avalanches and shows intensity and statistical properties which arefavorably compared to the burst activity of soft 
repeaters.
repeatersKondratyev, V. N.
JAERI-Research 2001-057, 74 Pages, 2002/01
JAERI-Research-2001-057.pdf:7.23MB
The magnetization of neutron star matter is considered within the thermodynamic formalism. The quantization effects are demonstrated to result in sharp abrupt magnetic field dependence of nuclide magnetic moments. Accounting for inter-nuclide magnetic coupling we show that such anomalies give rise to erratic jumps in magnetotransport of neutron star crusts. The properties of such a noise are favorably compared with burst statistics of Soft Repeaters.
Tsuboi, Hiroshi; Kanda, Keiji*
Nihon Genshiryoku Gakkai-Shi, 43(8), p.806 - 822, 2001/08
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)no abstracts in English
Saito, Kazuo*; Ishida, Toshihisa
JAERI-Tech 2001-039, 25 Pages, 2001/06
JAERI-Tech-2001-039.pdf:0.94MB
no abstracts in English
Yamagishi, Hideshi; Soyama, Kazuhiko; Kaneko, Junichi; Ikeda, Yujiro
JAERI-Tech 2000-085, 21 Pages, 2001/02
JAERI-Tech-2000-085.pdf:1.73MB
no abstracts in English
Nibe, Nobuaki; Shimakawa, Yoshio; ; Hayafune, Hiroki; ; ; Ichimiya, Masakazu
JNC TN9400 2000-074, 388 Pages, 2000/06
JNC-TN9400-2000-074.pdf:13.32MB
Large sized sodium-cooled fast breeder reactors of large-size are being studied and have been operated in Japan and many countries. ln this feasibility study, evaluation was made on technical feasibinty for design concepts or 1 loop type and 3 pool types, specially from the viewpoint of improvement of economical competence. The design concepts include the ideas of cost reduction measures such as large-scaled components, reduction of loop number and integration of components on the basic of utilization of sodium characteristics. From the results of the evaluation, it may be possible for all the concepts to attain the economical target of 200 thousands yen per kilowatt, though further confirmation should be made for technical feasibility of those concepts. ln addition, the following items were listed up as further cost-reduction measures. (1)Higher temperature cooling system and steam cycle efficiency (2)Shortening of construction term (3)Reduction of safety systems by using measuring instruments with high performmce (4)Adoption of SG-ACS
Yonomoto, Taisuke; Anoda, Yoshinari
IAEA-TECDOC-1149, p.233 - 246, 2000/05
no abstracts in English
B
O
Sugiyama, Akira; Gallagher, H. G.*; Han, T. P. J.*
JAERI-Tech 99-069, p.27 - 0, 1999/09
no abstracts in English
