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Okajima, Satoshi; Isobe, Nobuhiro*; Kawasaki, Nobuchika; Sukekawa, Masayuki*
Nihon Kikai Gakkai 2009-Nendo Nenji Taikai Koen Rombunshu, Vol.1, p.125 - 126, 2009/09
no abstracts in English
Nakatsuka, Toru; Yoshida, Hiroyuki; Takase, Kazuyuki
Nihon Kikai Gakkai 2009-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.141 - 142, 2009/09
In the thermal hydraulic design of supercritical water-cooled reactor, it is required to establish a design technique which can precisely predict heat transfer deterioration of supercritical water as the core coolant. The mechanism of heat transfer deterioration has not been figured out yet. In the present study, results of preliminary surveys on several turbulence models are reported. Large eddy simulation shows the most promising results for predictions of the heat transfer deterioration with a high accuracy.
production reactor for open-cycle thermochemical IS processKubo, Shinji; Onuki, Kaoru; Naito, Masaaki*; Tachibana, Yukio
Nihon Kikai Gakkai 2009-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.151 - 152, 2009/09
Merits of open-cycle thermochemical processes are characterized as compared with closed-cycle thermochemical processes to make water-splitting by unnecessity of high-temperature equipments, acceptable low thermal efficiency than water electrolysis to produce hydrogen, and conversions of unwanted materials into valuable materials. This study focuses a open cycle process to produce hydrogen and sulfuric acid from water and sulfur dioxide which is obtained from sulfur of general industry wastes. Improvement of hydrogen iodide decomposition rate by absorptions of reactant of iodine into active carbon was adapted to measure thermal burden on hydrogen production section. A heat requirement to drive a hydrogen production reactor with active carbon was estimated to be 194 kJ/mol-H, thereby heat input of total process was reduced from 6380 without active carbon to 1480 kJ/mol-H with that.
Kimura, Nobuyuki; Kobayashi, Jun; Kamide, Hideki
no journal, ,
Hot and cold fluids are mixed at the core outlet of sodium cooled fast reactors. The temperature fluctuation causes high cycle thermal fatigue in structural components. The temperature fluctuation at the core outlet region has not a sinusoidal waveform but an irregular spike waveform. In the study, the evaluation method for the high cycle thermal fatigue was investigated against the spike waveform of temperature fluctuation. It was found that the combinational method between the peak-to-peak value of temperature fluctuation and the frequency response function of structure could evaluate the fatigue damage in structure.
Kawasaki, Nobuchika; Kato, Shoichi; Yamauchi, Masafumi*; Nagae, Yuji; Kikuchi, Koichi*; Kasahara, Naoto
no journal, ,
To apply commercialized fast reactor, JSFR, creep fatigue evaluation method is developing to consider holding position during creep. In general thermal transients, creep hold position is intermediate position in the strain range. To consider holding position in the evaluation method, uni-axial intermediate hold type creep fatigue tests were performed and verified the evaluation method.
Naoe, Takashi; Futakawa, Masatoshi; Kawai, Masayoshi*
no journal, ,
Cavitation bubbles are formed by negative pressure which is induced through the pressure wave propagation due to proton beam injection. Pitting damage is formed by microjet impact during cavitation bubble collapse. The stainless steel with the multi-layered surface that consists of stainless steel and gold films was newly developed to mitigate the damage by microjet impact. In this study, thickness of the film layers were optimized through the numerical simulations. The damage and dynamic response were numerically compared between homogeneous and multi-layered surfaces. The stress wave propagations were evaluated along the interface between layers. The dynamic deformation of multi-layered surface is dependent on the thickness of layers and the stress propagation might be dispersed by the interface of multi-layered surface. It can be said that the multi-layered surface improvement is effective to reduce the localized stress due to impact.
Ito, Kei; Kunugi, Tomoaki*; Ohshima, Hiroyuki; Kawamura, Takumi*
no journal, ,
To evaluate the gas entrainment (GE) phenomenon in sodium-cooled fast reactors, two methods are proposed in this study. One is a CFD-based prediction method and the other is a high-precision numerical simulation method for interfacial flows. In the CFD-based prediction method, a theoretical flow model is applied to the CFD result obtained on a relatively coarse mesh to determine the indicators of the GE phenomenon, e.g. interfacial dent. This method was validated by evaluating the occurrence condition of the GE phenomenon in the full-scale testing of a fast reactor. On the other hand, several numerical algorithms were developed to achieve the high-precision numerical simulation of interfacial flows. In the development, physics-basis formulations were derived to improve the simulation accuracy on interface tracking. As a result, it was confirmed that the developed numerical simulation method can reproduce the GE phenomenon observed in a simple GE experiment.
Ohshima, Hiroyuki; Uwaba, Tomoyuki; Hashimoto, Akihiko*
no journal, ,
Adoption of higher burn-up core can be considered as one of effective methods to enhance economic competitiveness for the commercialization of sodium-cooled fast reactors and it becomes possible with evaluating and confirming structural integrity of fuel assemblies under high burn-up conditions. A numerical simulation system, which consists of a deformation analysis program and three kinds of thermal-hydraulics analysis programs, is being developed in Japan Atomic Energy Agency (JAEA) in order to offer methodologies to clarify thermal-hydraulic phenomena in fuel assemblies under various operating conditions. In this paper, an analysis method of thermal-hydraulics in a wire-wrapped and deformed fuel pin bundle using two kinds of component programs of the numerical simulation system and its application to an irradiated fuel assembly analysis are described.
Asayama, Tai
no journal, ,
This article discribes the concepts of the System based code and its status of evolution in Japan and overseas.
Ida, Masato
no journal, ,
The bubble-bubble interaction through pressure pulses has been studied to show that it can be a source of cavitation noise. A recent report demonstrated that the acoustic noise generated by a shrimp originates from the collapse of a cavitation bubble. The recorded noise consists of positive and negative pulses, but a model for single bubbles fails to reproduce the negative ones. Using a multibubble model we have shown that the negative pulses can be explained by considering the interaction of bubbles: Positive pulses produced at the collapse of bubbles hit neighboring bubbles to generate reflected pulses whose amplitudes are negative.
