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Journal Articles

Comparative methodology between actual RCCS and downscaled heat-removal test facility

Takamatsu, Kuniyoshi; Matsumoto, Tatsuya*; Liu, W.*; Morita, Koji*

Annals of Nuclear Energy, 133, p.830 - 836, 2019/11

A RCCS having passive safety features through radiation and natural convection was proposed. The RCCS design consists of two continuous closed regions: an ex-reactor pressure vessel region and a cooling region with a heat-transfer surface to ambient air. The RCCS uses a novel shape to remove efficiently the heat released from the RPV through as much radiation as possible. Employing air as the working fluid and ambient air as the ultimate heat sink, the RCCS design can strongly reduce the possibility of losing the working fluid and the heat sink for decay-heat-removal. Moreover, the authors started experiment research with using a scaled-down heat-removal test facility. Therefore, this study propose a comparative methodology between an actual RCCS and a scaled-down heat-removal test facility.

Journal Articles

Improvement of heat-removal capability using heat conduction on a novel reactor cavity cooling system (RCCS) design with passive safety features through radiation and natural convection

Takamatsu, Kuniyoshi; Matsumoto, Tatsuya*; Liu, W.*; Morita, Koji*

Annals of Nuclear Energy, 122, p.201 - 206, 2018/12

 Percentile:100(Nuclear Science & Technology)

A RCCS having passive safety features through radiation and natural convection was proposed. The RCCS design consists of two continuous closed regions: an ex-reactor pressure vessel region and a cooling region with a heat-transfer surface to ambient air. The RCCS uses a novel shape to remove efficiently the heat released from the RPV through as much radiation as possible. Employing air as the working fluid and ambient air as the ultimate heat sink, the RCCS design can strongly reduce the possibility of losing the working fluid and the heat sink for decay-heat-removal. This study addresses an improvement of heat-removal capability using heat conduction on the RCCS. As a result, a heat flux removed by the RCCS could be doubled; therefore, it is possible to halve the height of the RCCS or increase the thermal reactor power.

Journal Articles

Experimental study on heat removal performance of a new Reactor Cavity Cooling System (RCCS)

Hosomi, Seisuke*; Akashi, Tomoyasu*; Matsumoto, Tatsuya*; Liu, W.*; Morita, Koji*; Takamatsu, Kuniyoshi

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 7 Pages, 2018/11

A new RCCS with passive safety features consists of two continuous closed regions. One is a region surrounding RPV. The other is a cooling region with heat transferred to the ambient air. The new RCCS needs no electrical or mechanical driving devices. We started experiment research with using a scaled-down test section. Three experimental cases under different emissivity conditions were performed. We used Monte Carlo method to evaluate the contribution of radiation to the total heat released from the heater. As a result, after the heater wall was painted black, the contribution of radiation to the total heat could be increased to about 60%. A high emissivity of RPV surface is very effective to remove more heat from the reactor. A high emissivity of the cooling part wall is also effective because it not only increases the radiation emitted to the ambient air, but also may increase the temperature difference among the walls and enhance the convection heat transfer in the RCCS.

Journal Articles

Modeling of initial interaction between the laser pulse and Sn droplet target and pre-plasma formation for the LPP EUV source

Sasaki, Akira; Nishihara, Katsunobu*; Sunahara, Atsushi*; Nishikawa, Takeshi*

Proceedings of SPIE, Vol.9776, p.97762C_1 - 97762C_6, 2016/03

 Times Cited Count:1 Percentile:29.39

For the improvement of efficiency and output of the laser pumped plasma (LPP) extreme ultra-violet (EUV) light source, we present a hydrodynamics model of laser irradiated Sn targets. The model takes liquid/solid to gas transition and mixed phase condition of the flow into account for the calculation of the distribution of the particles produced by the pre-pulse laser irradiation and optimization of the EUV source. Firstly, we investigate the mechanisms of the fragmentation of the target and particle emission, including the effect of the equation of state of Sn, and secondly, an applicable model is proposed based on the analysis.

Journal Articles

Conference report; The 16th International Workshop on Radiative Properties of Hot Dense Matter

Sasaki, Akira; Nishimura, Hiroaki*; Onishi, Naofumi*

Purazuma, Kaku Yugo Gakkai-Shi, 91(2), p.166 - 167, 2015/02

no abstracts in English

Journal Articles

Shielding design of the ITER NBI Duct for nuclear and bremsstrahlung radiation

Sato, Satoshi; Iida, Hiromasa; Yamauchi, Michinori*; Nishitani, Takeo

Radiation Protection Dosimetry, 116(1-4), p.28 - 31, 2005/12

 Times Cited Count:2 Percentile:79.11(Environmental Sciences)

no abstracts in English

Journal Articles

Characterization of extreme ultraviolet emission from laser-produced spherical tin plasma generated with multiple laser beams

Shimada, Yoshinori*; Nishimura, Hiroaki*; Nakai, Mitsuo*; Hashimoto, Kazuhisa*; Yamaura, Michiteru*; Tao, Y.*; Shigemori, Keisuke*; Okuno, Tomoharu*; Nishihara, Katsunobu*; Kawamura, Toru*; et al.

Applied Physics Letters, 86(5), p.051501_1 - 051501_3, 2005/01

 Times Cited Count:102 Percentile:4.75(Physics, Applied)

no abstracts in English

Journal Articles

Effect of the satellite lines and opacity on the extreme ultraviolet emission from high-density Xe plasmas

Sasaki, Akira; Nishihara, Katsunobu*; Murakami, Masakatsu*; Koike, Fumihiro*; Kagawa, Takashi*; Nishikawa, Takeshi*; Fujima, Kazumi*; Kawamura, Toru*; Furukawa, Hiroyuki*

Applied Physics Letters, 85(24), p.5857 - 5859, 2004/12

 Times Cited Count:38 Percentile:19.17(Physics, Applied)

no abstracts in English

Journal Articles

Theoretical simulation of extreme UV radiation source for lithography

Fujima, Kazumi*; Nishihara, Katsunobu*; Kawamura, Toru*; Furukawa, Hiroyuki*; Kagawa, Takashi*; Koike, Fumihiro*; More, R.*; Murakami, Masakatsu*; Nishikawa, Takeshi*; Sasaki, Akira; et al.

Emerging Lithographic Technologies VIII, Proceedings of SPIE Vol.5374, p.405 - 412, 2004/00

no abstracts in English

Journal Articles

Potentiality of the laboratory astrophysics using high repetition rate and high intensity lasers

Nishiuchi, Mamiko; Daido, Hiroyuki; Takabe, Hideaki*; Matsukado, Koji*

Reza Kenkyu, 31(11), p.711 - 720, 2003/11

no abstracts in English

Journal Articles

6th Research Meeting of Young Scientists for Plasma Physics

Sakamoto, Yoshiteru; Nakano, Tomohide; Oyama, Naoyuki

Purazuma, Kaku Yugo Gakkai-Shi, 79(7), p.715 - 716, 2003/07

no abstracts in English

Journal Articles

Luminescence properties of lanthanide(III) ions in concentrated carbonate solution

Nagaishi, Ryuji; Kimura, Takaumi; Sinha, S. P.*

Molecular Physics, 101(7), p.1007 - 1014, 2003/01

 Times Cited Count:14 Percentile:53.62(Chemistry, Physical)

no abstracts in English

Journal Articles

Advanced high-temperature ultracentrifuge apparatus for mega-gravity materials science

Mashimo, Tsutomu; Huang, X.; Osakabe, Toyotaka; Ono, Masao*; Nishihara, Masamichi*; Ihara, Hirotaka*; Sueyoshi, Masanori*; Shibasaki, Koji*; Shibasaki, Shiro*; Mori, Nobuo*

Review of Scientific Instruments, 74(1), p.160 - 163, 2003/01

 Times Cited Count:51 Percentile:8.45(Instruments & Instrumentation)

An ultracentrifuge apparatus, which could generate an ultra-strong gravitational field of even $$>$$1,000,000 (1 million) G (1G = 9.8 m/s$$^{2}$$) in a wide temperature range up to $$>$$ 500$$^{circ}$$C with high stability controls, was developed for new materials science research. The system consisted of an air turbine motor with ceramic ball bearings and dumper section, a sample rotor with an outer diameter up to 160 mm, a vacuum chamber and a heating system. The ultracentrifuge experiments using the 70 and 80 mm-diam rotors made of titanium alloy with rotational speeds of up to 170,000 rpm at temperatures of even over 200$$^{circ}$$C for 100 hours with the ripples of $$<$$ 0.05% and $$<$$ 1 degree, respectively, were successfully performed, where the maximum gravitational field at sample was $$>$$1,000,000 G, and the potential energy and sample volume were larger than those of the Kumamoto University one (Rev. Sci. Instr. 67, 3170 (1996)) by $$>$$ 1.9 and $$>$$ 4 times, respectively.

JAEA Reports

Transport analysis of tungsten impurity in ITER-FEAT

Murakami, Yoshiki*; Amano, Tsuneo*; Shimizu, Katsuhiro; Shimada, Michiya; Ogawa, Yuichi*

JAERI-Research 2001-049, 58 Pages, 2001/11

JAERI-Research-2001-049.pdf:3.11MB

no abstracts in English

Journal Articles

Study on decay heat removal of compact ITER

Tsuru, Daigo; Neyatani, Yuzuru; Araki, Takao*; Nomoto, Kazuhiro*; Ohira, Shigeru; Maruo, Takeshi; Hashimoto, Masayoshi*; Hada, Kazuhiko; Tada, Eisuke

Fusion Engineering and Design, 58-59, p.985 - 989, 2001/11

 Times Cited Count:3 Percentile:69.85

no abstracts in English

JAEA Reports

Shielding calculation constants for use in effective dose evaluation for photons, neutrons and bremsstrahlung from $$beta$$-ray

Sakamoto, Yukio; Endo, Akira; Tsuda, Shuichi; Takahashi, Fumiaki; Yamaguchi, Yasuhiro

JAERI-Data/Code 2000-044, 191 Pages, 2001/01

JAERI-Data-Code-2000-044.pdf:7.19MB

no abstracts in English

JAEA Reports

Development and validation of Multi-DimensionaI sodium combustion analysis code AQUA-SF

; Yamaguchi, Akira

JNC-TN9400 2000-065, 152 Pages, 2000/06

JNC-TN9400-2000-065.pdf:6.26MB
JNC-TN9400-2000-065(errata).pdf:0.12MB

ln the liquid metal fast reactor (LMFR) using liquid sodium as a coolant, it is important to evaluate the effect of the sodium combustion on the structure, etc. Most of the previous analytical works are based on a zone model, in which the principal variables are treated as volume-average quantities. Therefore spatial distribution of gas and structure temperatures, chemical species concentration are neglected. Therefore, a multi-dimensional sodium combustion analysis code AQUA-SF (Advanced simulation using Quadratic Upstream differencing Algorithm - Sodium Fire version) has been developed for the purpose of analyzing the sodium combustion phenomenon considering the multi-dimensional effect. This code is based on a multi-dimensional thermal hydraulics code AQUA that employs SIMPLEST-ANL method. Sodium combustion models are coupled with AQUA; one is a liquid droplet model for spray combustion, and the other is a flame sheet model for pool combustion. A gas radiation model is added for radiation heat transfer. Some other models necessary for the sodium combustion analysis, such as a chemical species transfer, a compressibility, are also added. ln AQUA-SF code, bounded QUICK method in space scheme and bounded three-point implicit method in time scheme are implemented. Verification analyses of sodium combustion tests shown in the following have been carried out. (1)pool combustion test (RUN-D1) (2)spray combustion test (RUN-E1) (3)sodium leakage combustion test (Sodium Fire Test-II) (4)smaII-scale leakage combustion test (RUN,F7-1) ln each verification analysis, good agreements are obtained and the validity of AQUA-SF code is confirmed.

Journal Articles

$$gamma$$-ray buildup factors for a point isotropic source in the single layer shield by using BERMUDA code

Sakamoto, Yukio; Suzuki, Tomoo*; Sato, Osamu*; Hirayama, Hideo*

Journal of Nuclear Science and Technology, 37(Suppl.1), p.484 - 487, 2000/03

no abstracts in English

Journal Articles

Atomic processes involving doubly excited levels in low temperature dense plasma; Recombination X-ray laser

Kawachi, Tetsuya

NIFS-PROC-44, p.69 - 72, 2000/01

no abstracts in English

Journal Articles

X-ray pumping source for inner-shell ionization X-ray laser

Moribayashi, Kengo*; Sasaki, Akira; Ueshima, Yutaka*; Tajima, Toshiki*

Inst. Phys. Conf. Ser., (159), p.321 - 324, 1999/00

no abstracts in English

55 (Records 1-20 displayed on this page)