Development of marine heat recovery system is considered as one of the useful device to improve the energy efficiency, and motion prediction of the catalyst in system to the motion of a marine wave is an important element. Then, in this research, the visualization in waving circulating fluidized bed was performed using the capacitance CT. Capacitance CT is the system that measures a dielectric constant between electrode pairs attached to the circumference of a pipeline and calculates the particle concentration distribution in a pipe from the value. This result shows change for different flow state and waving situation. In this experiment, the particle concentration in the pipe became (in the case of a wave state) lower compared with the upright state.

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Due to the interactions between particle - flow, particle - particle and particle - wall, the behavior of solid particles in gas-fluidized beds is very complicated. A number of numerical models have been developed and its expansion to include heat and mass transportation is performed by several researchers at present. These are highly influenced by the dispersion and mixing characteristics of particle and it is important to know the motion of individual particles to develop reliable models. In the present study, a velocity measurement of individual particles is performed in a two-dimensional fluidized bed by using particle tracking velocimetry (PTV). For comparisons, corresponding DEM-CFD coupling simulations is also carried out.

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Buoyancy-driven exchange flows of helium-air through horizontal and inclined small openings were investigated. Exchange flows may occur following the opening of a window for ventilation, when fire breaks out in a room, as well as when a pipe ruptures in a high temperature gas-cooled nuclear reactor. The experiment in this paper was carried out in a test chamber filled with helium and the flow was visualized using the smoke wire method. The flow behavior was recorded by a high-speed camera combined with a computer system. The image of the flow was transferred to digital data, and the flow velocity was measured by PTV software. From the experiment, it is clear that the inclination angle for the maximum flow rate is 30 degree.

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Recently, a new chemical extraction method using Taylor-Couette vortex flow (T-CVF) is expected, because the extraction agent's contact and dispersion efficiency can be improved by use of T-CVF. Using this method, the amount of solvent and extraction agent can be reduced compared with the conventional methods, and environmental degradation and cost reduction are expected. For realizing the practical usage of this method, it is important to investigate T-CVF characteristics with axial flow including the inlet and the outlet. Therefore, in this study, we investigated the effects of axial flow on T-CVF structure using an Ultrasonic Velocity Profile monitor (UVP) can measure flow dynamic characteristics. From the measurement result, in the case with axial flow, the lift up phenomenon of T-CVF was confirmed.

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Gas liquid inter is formed in a pressurizer spray pipe of a pressurized water reactor when flow rate is small at normal reactor operation. Temperature fluctuation may occur it the interface moves periodically. Measurement of inner wall and fluid temperature in the test section simulating the real pressurizer spray pipe was conducted to study mechanism of the temperature fluctuation phenomena. Experiments with and without non-condensable gas, air were conducted. The significant temperature fluctuation was not observed in air-water system and air- vapor-water system. The temperature fluctuation was observed in vapor-water system. Visualization was carried out at the horizontal part of the spray pipe. No interface movement was observed but vortices in the liquid layer near the interface were observed without non-condensable gas. It was estimated that Kelvin-Helmholtz instabilities occurred in the liquid layer near the interface.

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Flooding is one of very important designing factor of actual boiling system with counter-current two-phase flow. Consequently, many investigations have been conducted so far, but most of those investigations have been done with large diameter tubes. Thus, flooding characteristics under a small diameter tubes (I.D.<10 mm) have not been fully understood so far. In this study, flooding experiment was conducted by using air-water isothermal system with glass and acrylic resin tubes of 5 mm in inner diameter. As results, the wettability of tube material did not influence on the critical flooding and deflooding velocity, but influenced on the flooding velocity and flooding pattern transitions. And these flooding velocities were estimated by using Wallis's equation.

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Many pipes branch off from a main pipe in industrial plants. Hot water penetrates into the branch pipe with a cavity flow induced by the main flow when temperature of liquid in the main pipe is higher than that in the branch pipe. The penetration causes thermal stratification in the branch pipe. The cavity flow causes a spiral flow with long period fluctuations. The thermal stratification layer fluctuated and caused fluctuations of the wall temperature at an elbow of the branch pipe when the burst phenomena occurred. Visualization tests were conducted to study mechanism of the flow phenomena. It was found that the penetration depth increased with increasing the pipe diameter.

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A new and rigorous modeling of basic transport equation of interfacial area concentration was carried out. Based on the local instant formulation of gas-liquid two-phase flow, basic transport equation of interfacial area concentration was rigorously formulated. In the basic transport equations, the averaged interfacial velocity was shown to be correlation functions of fluctuation of velocity and local instant void fraction and their derivatives which reflect the transport of interfacial area concentration due to interaction between interfacial area and turbulence of each phase. Basic conservation equations of spatial correlation functions of characteristic function and velocity of each phase were also derived based on the conservation equations momentum and its fluctuation of each phase.

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Free surface fluctuation on a high speed water jet has been measured employing a laser beam refraction technique. The obtained free-surface slope angle data were divided into each wave period using the zero-up-crossing method and wave speed was estimated from the cross-correlation between fluctuations at two measuring locations. Two-dimensional waveform was calculated as a time integration of slope angle data. For jet average velocity U=6 to 10 m/s, the streamwise variation of ensemble averaged wave steepness takes a maximum at a certain distance from nozzle exit. Some samples of waves indicate the waveform similar to the Stokes wave at the location downstream of maximum wave steepness. On the contrary, the probability density function of non-dimensional wave height records the different profile with the Rayleigh distribution.

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The carry-under that bubbles are rolled into a pool when a liquid column/jet or a liquid film on a wall flows down into a liquid pool was examined. When the flow rate was low, the liquid column disrupted into liquid lumps. A dent was formed on the pool surface by the liquid lumps hitting the pool surface. Gas in the dent was pulled down into the liquid pool. The disruption of the jet was well explained with the Kelvin-Helmholtz instability. As the flow rate was increased, the surface of the liquid jet became smooth and the carry-under ceased. As the flow rate was further increased, the surface of the liquid jet became disturbed condition. By the disturbance dents were formed periodically on the pool surface and gas in the dents was pulled down into the pool with the jet flow. The penetration of the bubbles into the pool became deep.

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Recently, microbubbles are utilized in various engineering fields. We focus on one of the microbubble generator which is shaped a Venturi tube. Microbubbles are generated with breakup of bubbles due to the rapid pressure recovery in it even under the high void fraction conditions. In order to clarify the mechanism of the bubble breakup and to optimize the generator to apply in various fields, changing of void fraction through a Venturi tube and the generated bubbly are necessary. We applied an electro-void fraction meter proposed in nuclear power engineering field to measure void fraction of microbubbles. The principle of the meter is that electrical resistance of air-water two-phase flow changes with the void fraction. In this study, we discussed possibility of measurement of bubbly flow with microbubbles by Constant-Electric-Current-Method (CECM) and effectiveness of Maxwell's theory. As a result, it was confirmed that the void fraction measurement of microbubbles with the present method was possible with Maxwell's theory which is used for estimation of the correlation between void fraction and resistance.

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This experimental research concerns an air-bubble-jet flow in water. The authors try to conduct the measurements of the flow applying a three-dimensional particle-tracking-velocimetry (3D-PTV) technique, in order to show both air-bubble and liquid (water) velocities. As tracers, we regard air bubbles in bubble-velocity measurements, and we regard polyethylene particles suspended in the liquid in liquid-velocity measurements. Then, we visualise the three-dimensional motions of air bubbles and ambient liquid. As we record stereo images using two high-speed video cameras, we can get timely-consecutive information of air-bubble and ambient-liquid motions. As a result, we quantitatively reveal the three-dimensional instantaneous motion of an unsteady bubble-jet plume from a simple air nozzle.

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It is known that small quantities of surfactant additives can greatly reduce the friction factors during the flow of a heat transfer medium. The friction factors are reduced because the generation of turbulent vortices is suppressed by the formation of rod-like micelles, and the flow remains laminar in the high Reynolds number range. However, the values of heat transfer coefficients decrease during flow laminarization. The research objective is to study the heat transfer enhancement effect of micro-bubble injection. This paper presents an experimental investigation of the heat transfer and flow characteristics of an air-surfactant solution two-phase flow through a horizontal pipe. In the experiment, micro-bubble was injected through three types of porous metal. The experimental results are as follows. The flow patterns of air-surfactant solution two-phase flow depend on the size of micro-bubble. The heat transfer coefficient is promoted by micro-bubble injection, but the effect depends on the flow pattern or the size of micro-bubble.

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In order to improve the performance of steam stop/contraol valve, effect of strainer blind plate position, outlet pipe direction and layout of valve chamber were studied through numerical analysis and model test. The numerical analysis in this study made it possible to predict the complex three dimensional flow that exist in the valve, and the calculated results of the pressure loss were compared with the model test results. The optimization of valve chamber layout size were executed with DOE by using numerical analysis, and the good performance steam valve could be obtained.

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In order to enhance the thermal efficiency, Toshiba Corporation is developing the Advanced Ultra Super Critical (A-USC) steam turbine system with technical innovations and the reliable design philosophy. A-USC steam turbine is operated with steam temperature over 700℃, whose thermal efficiency is better and CO_2 emission less than conventional USC plant. There are many aspects and areas of technology for the realization of such steam conditions, for instance, material development, cooling design, casing design, and so on. In this paper, mainly system design, turbine structure and cooling system are described.

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CO2 emission-reduction targets is strict from the viewpoint of global warming year by year. Especially, coal-fired power generation emits the largest volume of CO2 for electricity due to its nature as a fossil fuel. But coal will continue to be located energy mainly because of its reserves, and more stable than others, therefore it must be effectively used. Hitachi is addressing this important issue. For some time in the future, coal-fired power generation will be a leading global power generation method with high efficiency. Hitachi has developed most-advanced steam turbine for coal-fired power generation with ultra super critical steam condition. As one of this solution, the feature and the brief of the steam turbine installed in the new unit-2 of Isogo thermal power station of Electric Power Development Co., Ltd., are described below.

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Demands for reducing carbon dioxide emissions from coal-fired power plants are considerably increasing from the viewpoint of preserving the global environment. Therefore, a key issue is improving thermal efficiencies for coal-fired power plants, which cover about 40% of the electric power in the world. The development of 700℃ class advanced ultra super critical plant is one of urgent issues for the reduction of carbon dioxide emissions. An evaluation concerning the technology development of the 700℃ class USC plant is being carried out in Europe and the United States. In Japan, the 700℃ class USC technology was finally adapted for one of national projects 2008. This paper describes the development issues and progress of the turbine material and the structures for 700℃ class USC. It especially introduces the development situation of two kinds of unique Ni base alloy.

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Integrated coal Gasification Combined Cycle system (IGCC) is higher thermal efficiency, since the system does combined power generation with product gas from gasifier. In Japan, the development of IGCC with the air-blown gasifier is being executed by electric power companies jointly. IGCC Demonstration Project is being promoted so as to demonstrate the reliability, durability and economical competitiveness as final step to commercialize. The project is being conducted by Clean Coal Power R&D Co., Ltd. (CCP). The fund and personnel for CCP are contributed by nine regional electric power companies, J-POWER, and CRIEPI. The EPC contract of the entire plant was ordered to Mitsubishi Heavy Industries, Ltd. (MHI). The durability test for 5000hours has been carrying out since June 2009. A sub-bituminous coal was tested in the plant and the power output using sub-bituminous coal reached 200MW.

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Combustion properties of coal gasification gas with CO_2 dilution were investigated for a newly proposed IGCC power generation system with CO_2 capture. In this system, the gasification gas is burned under high CO_2 concentration atmosphere. The laminar and turbulent burning velocities were measured for outwardly propagating stoichiometric H_2/O_2/CO_2 flames under the condition of constant flame temperature of 1300, 1500, 1700 and 2135℃. At the flame temperature of 1300, 1500 and 1700℃, the unstretched laminar burning velocities, u_1 were smaller than those of H_2/O_2/N_2 flames. However, u_1 of H_2/O_2/CO_2 flames were lager than those of H_2/O_2/N_2 flames at 2135℃. The ratios of the turbulent burning velocities at the flame radius 30mm, u_<tn(30mm)> to u_1 were larger than those of H_2/O_2/N_2 flames at all flame temperatures. Increase in the turbulence Karlovitz number and decrease in the Markstein number by the CO_2 dilution might cause the increase in u_<tn(30mm)> / u_1 of H_2/O_2/CO_2 flames.

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All Existing Blast Furnace can begin new IGCC business by adding more 200kg/ton-iron coal-gasfication. But it is not easy to success this new business, the more 200kg/ton-iron coal-gasfication has big trouble of increasing much pressure drop of Blast Furnace. This paper proposes that the consentration of Reductive-Gas (H_2 & CO) becomes near twice, by adding steam & pure O_2 to hot air, and COG (Coke Oven Gas) injection into tuyere as pulverized coal carrier gas. Because this high consentration of Reductive-Gas improves finely gas-permeability of Blast Furnace and is useful for fuel gas of High-temperature-Class IGCC.

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This paper deals with the experimental and numerical studies of aero-thermal characteristics of film cooling for turbine blade leading edge having three differently hole geometries. The hole geometries used in this study are called typeA and typeB. The purpose of this study is to sort out the most suitable hole geometry. Mainstream Reynolds number based on the cylinder diameter was 86,000. The effect of blowing rates (BR) was studied of various blowing ratios of 1.0 and 2.0. Transient techniques using thermochromic liquid crystal is used to measure film effectiveness and heat transfer coefficient. In addition, Detailed investigation of film cooling for leading edge is carried out using CFD simulations. RANS applying a Shear Stress Transport turbulence model is addressed to solve thermal convection. Results show that the typeA provide better film cooling performance on BR=1.0 than typeB.

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A design study for a 150 kW class radial inflow steam turbine system for the bottoming cycle in 2.4 MW class gas engine systems has been completed. A two-stage condensing turbine system is applied to increase output power under the supplied steam conditions from the exhaust heat of the gas engines. T he pressure ratio of a high-pressure turbine is 3.5, and that of a low-pressure turbine is 4.6. The blade profiles of both turbines are also designed to make sure the thrust does not exceed 300 N at the rated rotational speed of 51,000 rpm. To simplify the rotor system and to reduce mechanical losses, a permanent magnet generator rotor is applied that is composed of turbine rotors in a common shaft supported by two water-lubricated bearings. The oil supply system is completely eliminated in the turbine system. Turbine profiles are specified in the study.

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Coal is one of the important energy sources due to its abundant reserve and the market of coal fired boiler are expected to increase further. However, when using coal, it is essential to reduce environmental burdens such as high CO_2 and NOx generation. We succeeded to decrease NOx generation by 40% with developed state-of-the-art low NOx coal burner based on the new innovative concept. Developed burner also contributes to CO_2 reduction, since boiler efficiency can be improved by operating with low excess air ratio (<10%) and low unburned carbon in fly ash due to enhanced ignition. Furthermore, NOx generation can be reduced in spite of low AA ratio condition, which mitigates corrosion of the boiler furnace wall by H_2S. Accordingly, new burner realizes substantially boiler operation and maintenance cost reduction.

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The integration of gas engine with gas turbine was developed as a potential high thermal efficiency technology for the advanced combined cycle systems. The high performance analysis was carried out to obtain the best engine operating condition in combined cycle systems. The effect of engine suction/exhaust pressure on the system performance was analyzed and found to be one of the major parameters. The engine pressure of LPS/LPE (low pressure suction and exhaust) and HPS/LPE (high pressure suction and low pressure exhaust) are proposed as the preferable conditions, enabling the expected thermal efficiency of around 65%LHV even with a low temperature gas turbine (TIT 1200℃ class).

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The development of a closed cycle gas turbine with super-critical carbon dioxide as a working fluid is under way in order to generate power from waste heat source of a low or intermediate temperature range from industry. Its demonstration test using a reduced scale turbomachine is under way. Principal specifications follow; net power output of 10kWe and recirculation CO_2 flow rate of 1.2kg/s under the given turbine inlet conditions of 550K and 12MPa respectively. Preliminary test results on the measurements of compressor required work is presented. Specific work input to compressor was measured and compared with analysis model that the specific work input is proportional to the value of compressibility coefficient at inlet to compressor. The model is proved to be valid.

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Ambient temperature effects and part-load characteristics of the AHAT (Advanced Humid Air Turbine) system were studied both experimentally and analytically. Firstly, these characteristics of the 3MW AHAT pilot plant were measured and they were compared with heat and material balance calculation results. Secondly, these characteristics of the AHAT and the combined cycle were calculated assuming they were composed of mid-sized industrial gas turbines which have axial flow compressors and axial flow turbines. As for the part-load characteristics, when the IGV (Inlet Guide Vane) were operated so as to keep the turbine exhaust temperature at a constant value, degradation of electrical efficiency of the AHAT was smaller than that of the combined cycle.

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This study is performed to examine experimental the burning velocity characteristics of hydrocarbon-premixed micro-scale spherical laminar flames with the flame radius r_f<approximately 5 mm, and also macro-scale laminar flames with r_f>7 mm for comparison, where methane or propane is used as hydrocarbon. The mixtures have nearly the same laminar burning velocity and different equivalence ratio φ(φ=0.8〜1.0 for methane mixtures, φ=0.8〜1.2 for propane mixtures). The radius, stretch and the burning. velocity of micro-scale flames are obtained by using sequential schlieren images recorded under appropriate ignition conditions. The results show that the burning velocities of micro-scale flames have tendency to increase with increasing r_f or decreasing the Karlovitz number and approach that of macro-scale flames. However, dependence on φ shows to be the difference between methane and propane mixtures.

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Micro gas turbine systems have been developed for a portable power supply. In this study kerosene spray with pre-vaporized system for the micro gas turbine combustor was tested. Fundamental characteristics of the kerosene spray with fuel vaporization on a hot wall were investigated experimentally. A model combustor of micro gas turbine was used for combustion test of kerosene spray. In the combustion test, an extension tubes were set at the exits of fuel injectors for the enhancement of pre-vaporization of kerosene spray. The effect of the extension tube on flame stability was discussed. As a result, the blow off limit became wider when the extension tube was set at fuel nozzle exit.

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We have developed a Joule-Thomson cooler utilizing a flexible concentric counterflow heat exchanger. In this study, we conducted a simulation to evaluate performance of the Joule-Thomson cooler in a comprehensive package which calculates heat transfer within the heat exchanger in addition to the temperature reduction due to the isenthalpic expansion. Two gases, C_2H_4 and CO_2 were compared. A separate simulation of the heat exchanger was constructed to examine heat exchanger performance of both gases in absence of JT expansion. Simulated results have confirmed experimental result revealing better performance of C_2H_4 despite its lower JT coefficient and lower heat exchanger effectiveness.

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We have developed a microcombustor which has a porous catalyst layer and investigated the flammability map and combustion characteristics for methane, butane and DME. For methane fuel, the flammable area in the lean condition is narrow. On the other hand for butane and DME, the flammable area in the lean condition is wide. This difference is caused by the difference in activation temperature of oxidation. Activation temperature of butane and DME is relatively low compared with that of methane, which leads to the fact that the combustion efficiency for butane and DME is lower than that of methane. In addition, higher air-fuel ratio at the stoichiometric condition for butane and presence of intramolecular oxygen for DME enhance the reaction in the lean condition. These different characteristics of the fuel affect the lower LHV limits, ignition temperatures and combustion efficiencies.

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Ti-coated Si microcavity have been developed as a selective emitter for micro thermovoltaic power generation system. For microcavity fabricated with vacuum arc evaporation, the emittance spectra correspond well to the electromagnetic resonance modes. By using a Ge PVcell, energy conversion efficiency with the present microcavity at 900℃ is found to be 3.4 %, which is in good agreement with the estimates with an equivalent circuit model. It is estimated that the energy conversion efficiency is increased to 12.3 % for the emitter temperature of 1200℃

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Flexible Joule Thomson micro-cooler was fabricated and its performance was examined. The micro-cooler has aimed at the spot cooling, and consists mainly of double-tube type countercurrent heat exchanger (outer diameter of outer tube is respectively 0.80, 0.75, 0.70mm and that of inner tube is 0.4mm. The length of it is 450mm.) and capillary (outer diameter of it is 0.2mm and its length is 50mm.). The micro-cooler uses N_2, C_2H_4, CO_2 as a working gas which were tested for pressures ranging from 0.5MPa to 5MPa. Capillary outlet temperature depends on the thermal properties of working gases.

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We have proposed the microactuators driven by liquid crystalline materials. In this work, two types of liquid crystalline microactuators are developed, which are the slider-type and motor-type liquid crystalline microactuators. The slider-type actuator is constituted with two parallel glass plates and a liquid crystalline material between them. The upper glass plate is just placed on the liquid crystal, and thus moves when the flow of the liquid crystal is induced by an pulsed electric field. From the results, it is found that the velocity of the upper plate can be controlled by adjusting the frequency of the pulsed voltage. On the other hand, the liquid crystalline motor have a structure that two glass cylinder with different diameters are coupled and a gap between the cylinder is filled with the liquid crystal. We have successfully drive the inner cylinder by applying the pulsed voltage on the liquid crystal and the rotation speed is about 8rpm when the frequency of the pulsed voltage is 100Hz.

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A novel charging method for vertical electrets in narrow gaps using soft X-rays has been developed. Electrets can be charged up to the depth 20〜30 times of the gap opening. With the present charging technology, MEMS electret transducers can be fabricated using a single wafer approach without any assembling process. We demonstrate performance of vertical electrets using early prototype of in-plane generator. Under 18.7μm_<p-p> external oscillation at 500 Hz, 30 mV output has been obtained without external bias voltage. Surface potential for 80 μm-deep vertical electrets is estimated to be 52 V.

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Sodium reacts chemically with water in case of unexpected heat transfer tube failure in a steam generator (SG) of sodium-cooled fast breeder reactors (FBRs), exoergic reaction produces reaction field with high temperature and high corrosive action (sodium-water reaction). Adjacent tubes are damaged due to erosive and corrosive environment of the reaction field. Therefore, it is integral to evaluate such sodium-water reaction phenomena with high accuracy for the safety assessment of FBRs. For the purpose of understanding the wastage mechanism, an experiment was carried out in which sodium hydroxide (NaOH) collided with the tube material under high temperature conditions simulating the reaction field. We confirmed that the erosion-corrosion rate of tube material has a tendency to increase as the temperature and velocity of NaOH are raised.

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This paper deals with the numerical investigation of thermal striping phenomena in a T-junction piping system (T-pipe) as the typical part where influential temperature fluctuation in structural integrity may be induced by the thermal mixing. Numerical simulations for a T-pipe consisting of a rectangular duct for main stream and a circular pipe for branch stream were performed to investigate relation between large-scale eddy structure formation in the mixing area and temperature fluctuation generation on the wall. Moreover, water experiment and numerical simulation in the T-pipe to investigate thermal interaction between fluid and structure were conducted. In the experiment, temperatures at 2mm from the wall in fluid, on the wall and at 3mm inside from the wall in structure along a vertical trace line were measured simultaneously and they were compared with those of the numerical results. The numerical results indicate that the fluid-structure thermal interaction is necessarily considered for thermal fatigue estimation in the thermal striping phenomena.

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A computer program called SERAPHIM has been developed to calculate the multicomponent multiphase flow involving the sodium-water chemical reaction in a steam generator of sodium cooled fast reactors. In this study, numerical analysis of supersonic gas jets into liquid pools with or without chemical reaction was performed to validate the numerical methods. As validation for a non-reaction problem, the visualization experiment on the horizontal supersonic air jet into the water was analyzed. The behavior of the jet and the horizontal penetration length were reproduced very well. On the other hand, the experiment on the vertical supersonic chlorine jet into the Na-NaCl mixture was analyzed. The numerical result showed that the injected gas disappeared at a certain height. The estimated plume length showed good agreement with the experimental data. The numerical methods were found to be applicable to the multiphase flow with the supersonic gas jets and the chemical reaction.

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To evaluate gas entrainment (GE) phenomena in a large-scale sodium-cooled fast reactor, the authors are developing a high-precision numerical simulation algorithm for gas-liquid two-phase flows based on a volume-of-fluid methodology. In this simulation algorithm, the PLIC (Piecewise Linear Interface Reconstruction) algorithm is employed to achieve accurate interface-tracking. Moreover, physically appropriate formulations have been conducted on gas-liquid interfaces to eliminate unphysical behaviors. Thanks to this improvements, it is confirmed that the developed simulation algorithm can reproduce the GE phenomena in a simple experiment. In this study, the simulation algorithm is applied to a real-scale GE test to check the applicability of the algorithm to the GE phenomena in the fast reactor. The mesh resolution and boundary conditions are considered carefully to be suitable for the numerical simulation of the two-phase flow around inlet and outlet pipes. As a result, transient behaviors of the vortical flows around the pipes and the accompanied GE phenomena are simulated well. In particular, the origin of the flow which induces the GE phenomena is showed clearly. Finally, from the investigation of a lot of GE phenomena observed in the simulation result, it is verified that the GE phenomena by relatively strong vortical flows are important in terms of the GE suppression in the fast reactor.

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A conceptual design study of Japan Sodium-cooled Fast Reactor (JSFR) is in progress as an issue of the "Fast Reactor Cycle Technology Development (FaCT)" project in Japan. JSFR adopts a Selector-Valve mechanism for the failed fuel detection and location (FFDL) system. The Selector-Valve FFDL system identifies failed fuel subassemblies by sampling sodium from each fuel subassembly outlet and detecting fission product. One of the JSFR design features is employing an upper internal structure (UIS) with a radial slit, in which an arm of fuel handling machine can move and access the fuel assemblies under the UIS. Thus, JSFR cannot place sampling nozzles right above the fuel subassemblies located under the slit. In this study, the sampling method for indentifying under-slit failed fuel subassemblies has been demonstrated by water experiments.

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Reduction of plant construction cost is one of the most important issues for commercialization of fast reactors. From this point of view, an innovative containment vessel adopting steel plate reinforced concrete structure (SCCV) is developed for Japan Sodium-Cooled Fast Reactor (JSFR). Although SC structure is generally in practical use, performance after exposing high temperature is not investigated. An experimental study including loading and/or heating tests has been carried out to investigate the fundamental structural features, which would be provided to develop methodology to evaluate the feasibility of SCCV under the severe conditions. In this paper, the design feature, the design and evaluation conditions for SCCV of JSFR as well as the construction method are summarized.

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In the fast reactors, it's crucial to install an effective failed fuel detection and location (FFDL) system for the purpose of protecting workers from radiation exposure and reducing radiation contamination. A new type of FFDL technique focused on the gas tagging method has been proposed by using resonance ionization mass spectrometry (RIMS) for the isotope analysis of the Ar cover gas. Though precise analysis of ppt level Kr and Xe in Ar needed is difficult because of the Ar^+ and Ar_2^+ ions generated by the photoelectron, we could successfully decrease the signal amount of these ions by applying an electrode with a slit-type hole to permit ppt level detection of ^<80>Kr without any obvious Ar_2 interference. Some promising methods concerning effective utilization of laser light are also presented to increase the photoionization efficiency for further reliability improvement of RIMS in the FFDL system.

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While global warming has become more deeply concerned, it is vital for Japan, which has world's top energy efficiency, to proactively adopt renewable energy in consumer category to shift from high dependency of fossil fuels. As for such approach, we have made comprehensive analysis and determination for usage of solar thermal energy. Although it is one of the most effective green technology to reduce GHG emission today, number of installation in Japan has been declining as well as its market shrinking causing withdrawal of manufacturer from the division. On the other hand, installation of such equipments in abroad has been growing which tightened competition resulting in improvements of cost performance and technology, and eventually price-reduction. Thus, we have completed verification test of foreign-made solar heat panels on behalf of Ministry of the Environment and examined its usage, economic impact and influence of installation in order to stimulate domestic market of solar heat panel.

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Microgrids systems are composed of intermittent energy (e.g. photovoltaics and wind generation) and controllable energy (e.g. fuel-cell cogeneration system and gas engine cogeneration system). The microgrids can not make best use of the high combined efficiency of cogeneration system if the heat-to-power ratio through cogeneration system is different from the heat-to-power ratio from the demand side. So, we installed heat pump water heater in microgrids to adjust the heat-to-power ratio from the demand side. We used a simulation to determine the reduction of CO_2 emissions with microgrids. We observed that microgrids have the optimal composition proportion of cogeneration system and heat pump water heater.

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Recently, the global warming is a serious concern, and sustainable energy resources such as photovoltaic generation are in the spotlight because CO2-emission is a world common problem. However, the photovoltaic generation is unstable due to the change of sunlight and has the worry to cause difficulty in power system operation and control when introduced into distributed networks or demand side. As the countermeasures against these concerns, battery energy storage system (BESS) attracts worldwide attention. Therefore, the combination of PV generation system and BESS is necessary for environment and economy. In this paper, the reductions of total amount of CO2-emission and total cost are calculated when installed on demand side such as a company and a campus, and the optimal capacities of PV generation and BESS are obtained.

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Homogeneous Charge Compression Ignition (HCCI) combustion has attracted much interest as a combustion system that can achieve both low emissions and high efficiency. However, combustion proceeds extremely rapidly in the HCCI process due to simultaneous ignition at multiple locations in the cylinder. That characteristic makes it necessary to moderate the rapidity of HCCI combustion under high-load operation. In the present study, a blended fuel of dimethyl ether (DME) and methane, with each component having different ignition characteristics, and a supercharged HCCI engine were used to investigate the effects of the ignition timing and the ratio of the intake air volume and injected heat value on the heat release characteristics of the hot flame. The results suggest that a certain ratio of injected heat value and intake air volume is required to induce two-stage heat release from the hot flame when a blended fuel of DME and methane is used.

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Recently, sustainable energy resources that contribute the reduction of CO2 emission are in the spotlight all over the world in order to solve a serious problem of global warming and exhaustion of fossil fuels. The photovoltaic generation is expected to bring about the reduction of CO2 emission, and the Japanese government has decided that the total installed capacity of PV generation would be 53GW by 2030. However, the photovoltaic generation is required the large space to install PV panels compared with other renewable energy resources. Therefore, we must determine the proper installation and the usage of PV panels in the limited space to operate the photovoltaic generation most effectively and to improve its efficiency. In this study, we have investigated the characteristics of the photovoltaic generation obtained and have determined the optimal installation of PV panels and improved the efficiency of the photovoltaic generation.

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In this study, CO_2, O_2, N_2 were mixed and dissolved to the water by non-bubble dissolution device or microbubble nozzle, then the total carbonic acid was measured. The conspicuous difference was not seen in the quantity of total carbonic acid in non-bubble dissolution device and microbubble nozzle by the dissolution experiment result. In incubation experiment, the algal was cultured with the seawater which dissolved CO_2, and analyzed the growth rate of the algal in various conditions. The case of seawater which dissolved CO_2 at the growth rate of alga was higher than the case of seawater, and CO_2 may promote growth depending on a condition.

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The combined system of a solid-oxide fuel cell (SOFC) and a proton-exchange membrane fuel cell (PEFC) is developed. The proposed system consists of a SOFC-PEFC combined system and a photovoltaic system (PV) as the energy supply to a micro-grid. The exhaust heat of the SOFC is used for the steam reforming of the bio-ethanol gas with time shift utilization of the exhaust heat of the SOFC in optional time. The SOFC-PEFC combined system with the PV was introduced in a micro-grid of 30 residences in Sapporo, Japan. Three types of system operation of using the SOFC independent operation, PEFC independent operation and SOFC-PEFC combined system are used to supply the demand side. The power generation efficiency is investigated for different load patterns: average load pattern, compressed load pattern and extended load pattern. The power generation efficiencies of the proposed system in consideration of these load patterns were 27% to 48%.

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This paper describes construction of the Internal Temperature Model for NAS battery. NAS battery is paid attention to height of the energy density and easiness of maintenance in the field in the electric power system. The operation temperature of the NAS battery is high, and an internal temperature exceeds 300℃. To keep this temperature, heater has been introduced though the NAS battery is wrapped in the container where an insulated processing was done. Then it has aimed to reduce power consumption in the heater by paying attention to battery's heat radiation reaction when electricity is discharged, and designing the timing of the electrical charge and discharge, and to raise the combined efficiency. After the model with high accuracy is constructed, it is scheduled that the timing of the electrical charge and discharge is examined, and the best operating method is proposed.

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This paper describes on the Smart community for KOTO-ku in Tokyo, featuring to utilize the mooring vessels powers, the next generation electric vehicles, photovoltaic powers with disaster proof smart meters and newly introduced citizen institution. The purpose of community is to establish the carbon cutback and high security declared on the city master plan of KOTO-ku. Tokyo University of Marine Science and Technology (TUMST) and KOTO-ku have been cooperating in any aspect in the technology and consultations for various enterprises conducted in KOTO-ku. This is one of the cooperation work and TUMST proposed the plans for the effective energy utilization and high security.

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