gas cooling Articles
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Some lessons learnt from the use of PRA during the design phase
The development of the pebble bed module reactor (PBMR) as a gas cooled thermal reactor type includes the use of probabilistic risk assessment (PRA) during the design phases. This paper presents some of the basic issues and results of the application of PRA in the design process and as part of the licensing process.Keywords: PRA, PBMR design, design optimisation, risk criteria, pebble bed module ...
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Some insights on issues related to specifics of the use of probability, risk, uncertainty and logic in PRA studies
The paper presents the main results of the insights to a gas cooled reactor from the perspective of the following notions: probability, uncertainty, entropy and risk. Some results of the ongoing comparisons between the insights obtained from three models are presented. The approaches consider the PBMR nuclear power plant (NPP) as a thermodynamic installation and as a hierarchical system with or ...
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R&D effort on nuclear hydrogen production technology in China
An active programme of developing high-temperature gas-cooled reactors is being executed in China. A 10 MWth test reactor with spherical fuel elements was constructed in 2000 and is now under operation. Research and development of direct cycle helium turbine technology is being carried out. The industrial-scale demonstration plant of modular HTGR is being promoted. Regarding nuclear hydrogen R&D, ...
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RELAP5–3D transient modelling for NGNP integrated plant
The High–Temperature Gas–cooled Reactor (HTGR) is designed with outlet temperatures ranging between 750°C and 800°C. These high outlet temperatures enhance the power production efficiency and facilitate a variety of industrial applications. The objective of this study is to understand the response of the primary system to potential transients in the secondary system. For this analysis, the ...
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Chemical kinetics parameters of nuclear graphite gasification
This paper provides chemical kinetics parameters for the gasification of nuclear graphite grades of IG–110, IG–430, NBG–18 and NBG–25 and presents empirical correlations for their surface areas of free active sites as a function of mass. The kinetics parameters for the four elementary chemical reactions of gasification of these grades of nuclear graphite include the values ...
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Dynamical safety assessment of hydrogen production nuclear power plants using system dynamics method
Nuclear power plants for hydrogen production are investigated in the aspect of nuclear safety. The non–linear dynamical safety assessment is introduced for the analysis of the high temperature gas cooled reactor (HTGR) which is used for hydrogen production as well as electricity generation. The dynamical algorithm is adjusted for the safety assessment with an easier and reliable output. A ...
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Evaluation of nuclear knowledge management on light water reactor, high temperature gas-cooled reactor and fusion reactor: a case study of Japan Atomic Energy Research Institute (JAERI)
Within JAERI, funds invested in a 45-year study of light-water reactors (LWRs) totalled 4.2 b$ (billion dollars) for research, including human resources of 34,718 years. The benefits to taxpayers from this JAERI work were estimated to be about 6.3 b$, resulting in a favourable cost-benefit ratio of 1.5 (6.3/4.2). Funds invested in the 32-year study of high-temperature gas-cooled reactors (HTGRs) ...
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The system CFD approach applied to a pebble bed reactor core
The system CFD code Flownex is used to simulate the transient behaviour of complete thermal-fluid systems such as the Pebble Bed Modular Reactor. In the context of this system simulation, the complexities in modelling the reactor heat transfer is discussed, as well as appropriate methods of dealing with it. The versatility of the system CFD approach is illustrated with three possible topologies ...
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Safety assessment for the deficient operation data in the gas-cooled nuclear power plants for hydrogen production
The probabilistic safety assessment (PSA) is investigated in the case of the operational data shortage which is characteristic of the passive system in gas-cooled nuclear power plants (NPPs). Therefore, it is difficult to make a quantification of the PSA. One of the solutions is to compare the passive system and the active system. Using this comparison, one can find the priority of the passive ...
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A turbulent submerged swirling jet expansion in still air and entropy generation
Gas jets find cooling and heating applications in industry. The swirling of jets improves flow mixing in the jet and modifies the flow structure significantly. In the present study, an isothermal submerged swirling air jet expanding into still air is considered and entropy generation, due to fluid friction in the flow field, is formulated and computed for different values of swirl number. It is ...
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On-Vehicle Exhaust Gas Cooling in a Diesel
ABSTRACT A diesel emissions control system built and tested on an industrial forklift truck is described. The system utilizes a pleated media type diesel soot filter. The temperature limit of the filter material is well below the temperature of the exhaust gas. Therefore, cooling of the exhaust gas is necessary. A finned-tube heat exchanger is included in the system to cool the exhaust gas to ...
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Effects of thermodynamic and mechanical irreversibilities on gas turbine performance enhancement by intake air cooling
A mathematical model for an existing gas turbine unit in Bahrain another model for intake Air Cooling Gas Turbine (ACIGT) with irreversibility's and variable specific heats were derived in dimensionless form. The maximum net power output and corresponding thermal efficiency were obtained using graphical visualisation and numerical calculation. Results showed an increases of 30% in output power ...
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Producing hydrogen using nuclear energy
The earliest means of separating hydrogen from water was by electrolysis using electrical energy that usually had been produced by low-efficiency thermodynamic processes. Substitution of thermal energy for electrical energy in high-temperature electrolysis gives a somewhat higher overall efficiency, but significantly complicates the process. Today, the vast majority of hydrogen is produced by ...
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Gas turbine performance enhancement by intake air cooling
In this work, the influence of air cooling intake on the gas turbine performance is presented. The proposed system, together with the gas turbine, is described. A mathematical model of ACIGT (Air Cooling Intake Gas Turbine) is derived and formulated in dimensionless form from which the constraint multivariable optimisation problem was formulated. To demonstrate the effectiveness of the proposed ...
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Diagnosing the effects of pilot fuel quality on exergy terms in a biogas run dual fuel diesel engine
This work presents the exergy balances of biogas dual fuel combustion modes using two different pilot fuels in a single-cylinder diesel engine. The main focus is on the use of biodiesel (BD) as a pilot in place of fossil diesel fuel. The results reveal that the important exergy loss recovery sources are the exhaust gas and cooling water exergy. By accessing these losses, there is an increase of ...
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Accident analysis for nuclear power plants with modular high temperature gas cooled reactors
This report on modular high temperature gas cooled reactors (modular HTGRs) is intended to supplement the IAEA Safety Standards Series. The publications in this series related to the present report are the Safety Requirements on Safety of Nuclear Power Plants: Design [1] and the Safety Guide on Safety Assessment and Verification for Nuclear Power Plants [2]. Clarification of the accident analysis ...
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Accident analysis for nuclear power plants with modular high temperature gas cooled reactors
BACKGROUND This report on modular high temperature gas cooled reactors (modular HTGRs) is intended to supplement the IAEA Safety Standards Series. The publications in this series related to the present report are the Safety Requirements on Safety of Nuclear Power Plants: Design [1] and the Safety Guide on Safety Assessment and Verification for Nuclear Power Plants [2]. Clarification of the ...
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Thermodynamic and economic assessments of gas turbine inlet air-cooling by evaporative technique
In this study, the effects of gas turbine inlet air-cooling by evaporative technique on work output and thermal end exergy efficiency were analysed. These analyses are performed with the use of per unit volumetric flow, which is fixed regardless of atmospheric air conditions. In addition, a simple and effective model is developed for the economic analysis of evaporative cooling. As a case study, ...
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Exergy analysis of a diesel engine cycle and its performance improvement
This paper aims to evaluate available energy losses, i.e. exergy losses caused by irreversible processes in the theoretical cycle of two-stroke and four-stroke diesel engines. All exergy losses in these cycles have been divided into three categories: exergy loss in the heat receiving process which is inevitable in thermal power systems; exergy loss in the scavenging process peculiar to the ...
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Diagnosing the effects of pilot fuel quality on exergy terms in a biogas run dual fuel diesel engine
This work presents the exergy balances of biogas dual fuel combustion modes using two different pilot fuels in a single–cylinder diesel engine. The main focus is on the use of biodiesel (BD) as a pilot in place of fossil diesel fuel. The results reveal that the important exergy loss recovery sources are the exhaust gas and cooling water exergy. By accessing these losses, there is an increase of ...
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