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Journal Articles

Nuclear reactor calculations

Okumura, Keisuke; Oka, Yoshiaki*; Ishiwatari, Yuki*

Nuclear Reactor Design, p.49 - 126, 2014/00

As necessary knowledge for nuclear reactor design, fundamental methods of nuclear reactor calculations are described. First, we explain, in an easy-to-understand manner, what kinds of numerical methods and procedures are employed in the codes which treat nuclear data processing, lattice calculation, lattice burnup calculation, core calculation, nuclear and thermal-hydraulic coupled calculation, core burnup calculation and space-dependent core calculation. Next we show the calculated examples of the optimizations for a fuel loading pattern and control rod insertion pattern in the thermal-hydraulic coupled core burnup calculation. Furthermore, we describe the methods of the plant dynamics analyses using a simple node junction model for the heat transfer calculation. The plant dynamics cover the analyses of control and startup properties, reactor stability, and safety analysis.

Journal Articles

A Large-scale three-dimensional simulation on thermal-hydraulics in a fuel bundle for SCWR

Misawa, Takeharu; Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*; Oka, Yoshiaki*

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo (SNA & MC 2013) (CD-ROM), 2 Pages, 2013/10

Journal Articles

Measurements of neutron capture cross section of $$^{237}$$Np for fast neutrons

Harada, Hideo; Nakamura, Shoji; Hatsukawa, Yuichi; Toh, Yosuke; Kimura, Atsushi; Ishiwatari, Yuki*; Yasumi, Atsushi*; Mabuchi, Yukio*; Nakagawa, Tsutomu*; Okamura, Kazuo*; et al.

Journal of Nuclear Science and Technology, 46(5), p.460 - 468, 2009/05

 Times Cited Count:4 Percentile:30.6(Nuclear Science & Technology)

The neutron capture cross section of $$^{237}$$Np has been measured for fast neutrons supplied at the center of the core in the Yayoi reactor. The activation method was used for the measurement, in which the amount of the product $$^{238}$$Np was determined by $$gamma$$-ray spectroscopy using a Ge detector. The representative neutron energy and the corresponding capture cross section of $$^{237}$$Np in the experiment were analytically deduced as 0.80 $$pm$$ 0.04 b at 0.214 $$pm$$ 0.009 MeV from the measured reaction rate by combining the energy dependence of the cross section in the nuclear data library ENDF/VII.0. The deduced cross section of $$^{237}$$Np at the representative neutron energy agrees with the evaluated data of ENDF/B-VII.0, but shows 15% larger value than that of JENDL-3.3 and 13% larger value than that of JENDL/AC-2008.

Journal Articles

Research and development of a super fast reactor, 8; Heat transfer experiments around a simulated fuel rod with supercritical pressure water

Ezato, Koichiro; Akiba, Masato; Enoeda, Mikio; Suzuki, Satoshi; Seki, Yohji; Tanigawa, Hisashi; Tsuru, Daigo; Mori, Hideo*; Oka, Yoshiaki*

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

no abstracts in English

Journal Articles

Rationalization of the fuel integrity and transient criteria for the super LWR

Yamaji, Akifumi*; Oka, Yoshiaki*; Ishiwatari, Yuki*; Liu, J.*; Koshizuka, Seiichi*; Suzuki, Motoe

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 7 Pages, 2005/05

Ensuring the fuel integrities is one of the most fundamental parts in the High Temperature Supercritical-Pressure Light Water Reactor. Most abnormal transient events of SCLWR-H last for a short period of time and the fuel rods are replaced after being irradiated in the core. In this study, the fuel integrity criteria are rationalized based on the fact that the fuel rod mechanical failures can be represented by the strain of the fuel rod cladding. A new fuel rod is designed with a Stainless Steel cladding. It is internally pressurized to reduce the stress on the cladding and also to increase the gap conductance between the pellet and the cladding. The fuel integrities both at normal operation and abnormal transient conditions are evaluated using the fuel analysis code FEMAXI-6 of JAERI.

Journal Articles

Startup thermal considerations for supercritical-pressure light water-cooled reactors

Nakatsuka, Toru; Oka, Yoshiaki*; Koshizuka, Seiichi*

Nuclear Technology, 134(3), p.221 - 230, 2001/06

 Times Cited Count:17 Percentile:74.89(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Start-up of superciritical-pressure light water cooled reactors

Nakatsuka, Toru; Oka, Yoshiaki*; Koshizuka, Seiichi*

Proceedings of 8th International Conference on Nuclear Engineering (ICONE-8) (CD-ROM), p.9 - 0, 2000/00

no abstracts in English

JAEA Reports

None

Oka, Yoshiaki*; Koshizuka, Seiichi*

PNC TY9602 98-002, 100 Pages, 1998/03

PNC-TY9602-98-002.pdf:2.24MB

no abstracts in English

JAEA Reports

None

Oka, Yoshiaki*; Koshizuka, Seiichi*

PNC TY9602 97-005, 66 Pages, 1997/03

PNC-TY9602-97-005.pdf:1.37MB

no abstracts in English

JAEA Reports

Prediction of sodium leakage and combustion phenomena

Oka, Yoshiaki*; Koshizuka, Seiichi*

PNC TY9602 97-003, 96 Pages, 1997/03

PNC-TY9602-97-003.pdf:4.41MB

None

JAEA Reports

None

; ; ; ; Yamaguchi, Akira; ;

PNC TN9420 96-052, 162 Pages, 1996/07

PNC-TN9420-96-052.pdf:7.04MB

None

JAEA Reports

None

; ; ; ; Yamaguchi, Akira; ;

PNC TN9420 96-051, 73 Pages, 1996/07

PNC-TN9420-96-051.pdf:2.35MB

None

JAEA Reports

None

; ; ; ; Yamaguchi, Akira; ;

PNC TN9420 96-040, 274 Pages, 1996/07

PNC-TN9420-96-040.pdf:12.25MB

None

JAEA Reports

Fundamental study of a particle method for thermal-hydraulic analysis

Oka, Yoshiaki*; Koshizuka, Seiichi*; Okano, Yasushi*

PNC TY9602 96-001, 133 Pages, 1996/03

PNC-TY9602-96-001.pdf:3.36MB

no abstracts in English

JAEA Reports

Fundamental study of a particle method for thermal-hydraulic analysis

Oka, Yoshiaki*; Koshizuka, Seiichi*

PNC TJ9602 95-001, 113 Pages, 1995/03

PNC-TJ9602-95-001.pdf:4.07MB

In order to enhance safety and economy of fast breeder reactors further more, numerical methods, which enables us to analyze large deformation of the domain due to, for instance, moving boundaries with satisfactory accuracy, should be developed. Since the fluid is represented by a group of particles in a particle method, it is easy to trace fluid flows by using the motion of particles. Fragmentation and coalescence as well as the large deformation of the fluid can be analyzed without any special techniques. The particle method the authors have been developing, however, needs much more computation time than that of the finite difference method in large problems at the moment. Thus improvement of the computation speed is focused on here as a fundamental study of the particle method. The dominant routine for the computation time in the code is the calculation of incompressibility because of implicit discretization. In the present study a correction parameter is optimized and listing of neighboring particles is incorporated, which has realized extensive improvement of the computation speed. The improved code is applied to a problem of propagation of surface waves at the coast where the water depth decreases uniformly. The waves are generated by oscillating motion of a vertical wall. This proves that moving boundaries can be dealt with in the particle method even if a free surface is involved.

Journal Articles

New approach to spin assignments of intermediate structures in $$^{12}$$C($$^{16}$$O,$$^{12}$$C[2$$_1^{+}$$])$$^{16}$$O

Sugiyama, Yasuharu; Tomita, Yoshiaki; Ikezoe, Hiroshi; Yamanouchi, Y.; Ideno, K.; Hamada, S.; Hijiya, M.*; Sugimitsu, Tsuyoshi *; Mukae, T.*; Nakamoto, K.*; et al.

Physical Review C, 49(6), p.3305 - 3308, 1994/06

 Times Cited Count:3 Percentile:18.28(Physics, Nuclear)

no abstracts in English

JAEA Reports

Review of the presented papers for the 7th International Conference on Radiation Shielding

Sasamoto, Nobuo; *; *; *; *; *; Kinno, Masaharu*; Sakamoto, Yukio; Sakurai, Kiyoshi; *; et al.

JAERI-M 89-122, 74 Pages, 1989/09

JAERI-M-89-122.pdf:2.52MB

no abstracts in English

JAEA Reports

Fusion neutron shielding benchmark problems

*; Sasamoto, Nobuo; Mori, Seiji*; *; Kawai, Masayoshi*; *; Sakurai, Kiyoshi; Shin, Kazuo*; Sekimoto, Hiroshi*; Oyama, Yukio; et al.

JAERI-M 87-203, 230 Pages, 1987/12

JAERI-M-87-203.pdf:4.46MB

no abstracts in English

JAEA Reports

None

Oka, Yoshiaki*

PNC TJ2602 87-002, 30 Pages, 1987/03

PNC-TJ2602-87-002.pdf:2.07MB

no abstracts in English

37 (Records 1-20 displayed on this page)