Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
Themanagement of spent nuclear fuel assemblies of nuclear reactors is a priority subject amongmember states of the International\nAtomic Energy Agency. For the majority of these countries, the destination of such fuel assemblies is a decision that is yet to be\nmade and the â??wait-and-seeâ? policy is thus adopted by them. In this case, the irradiated fuel is stored in on-site spent fuel pools\nuntil the power plant is decommissioned or, when there is no more racking space in the pool, they are stored in intermediate\nstorage facilities, which can be another pool or dry storage systems, until the final decision is made. The objective of this study is\nto propose a methodology that, using optimization algorithms, determines the ideal time for removal of the fuel assemblies from\nthe spent fuel pool and to place them into dry casks for intermediate storage. In this scenario, the methodology allows for the\noptimal dimensioning of the designed spent fuel pools and the casksâ?? characteristics, thus reducing the final costs for purchasing\nnew Nuclear Power Plants (NPP), as the size and safety features of the pool could be reduced and dry casks, that would be needed\nanyway after the decommissioning of the plant, could be purchased with optimal costs. To demonstrate the steps involved in the\nproposed methodology, an example is given, one which uses the Monte Carlo N-Particle code (MCNP) to calculate the shielding\nrequirements for a simplified model of a concrete dry cask. From the given example, it is possible to see that, using real-life data,\nthe proposed methodology can become a valuable tool to help making nuclear energy a more attractive choice costwise....
On Mauritaniaâ??s northern coast, wind and solar resources are abundant and\nmust be used effectively. These resources have the potential to completely or\npartially replace the existing or projected diesel generators. The main objective\nof this case study is to study the possibility of using a hybrid system (HS)\nof the type (diesel, wind and storage). The most important part of this case\nstudy intended for this area will be to add the solar in a first phase and then\nthe incorporation of an interconnection with the nearby network in a second\nphase. This interconnection will be secured by mean of medium voltage lines\nof 33 kV, where the nearest point is located 35 km away. Indeed, the study of\nthe optimization model is carried out through Homer, which was developed\nby National Renewable Energy Laboratory [NREL]. Thus, it should be noted\nthat the HS is analyzed on the basis of costs ($/kW) and price ($/kWh) and\ngreenhouse gas emissions. Therefore, in order to achieve these techno-\neconomic optimization objectives, this paper introduces a sensitivity\nanalysis that has been proposed to determine the effect of costs on each HS\nconfiguration. In the end, HSs are needed for maximum use of renewable resources\nat the studied site for an uninterrupted power supply....
This paper investigates the use of a combined hydrogen, heat, and power\n(CHHP) system for Omar Al-Mukhtar University campus using local resources.\nBased on previous local resource assessment studies, the hydrogen\nteam of Omar AL-Mukhtar University (OMU) selected the fuelcell energy\nDFC4000 (Trade Mark) unit. This study shows that the CHHP system can provide electricity\nto power the university campus, thermal energy for heating the anaerobic\ndigester, and hydrogen for transportation, back-up power and other\nneeds. Consequently, using the alternative fuels and renewable energy resources\nfor OMU campus can lower fossil fuel consumption and, therefore,\ngreenhouse gas emissions (GHG)....
The increasing CO2 concentration in the Earthâ??s atmosphere, mainly caused by fossil\nfuel combustion, has led to concerns about global warming. Carbonation is a technique that can\nbe used as a carbon capture and storage (CCS) technology for CO2 sequestration. In this study,\nthe utilization of the fly ash from a solid refused fuel (SRF) power plant as a solid sorbent material\nfor CO2 capture via semi-dry carbonation reaction was evaluated as a simple process to reduce\nCO2. The fly ash was exposed to accelerated carbonation conditions at a relative humidity of 25,\n50, 75, and 100%, to investigate the effects of humidity on the carbonation kinetics of the fly ash.\nThe reaction conditions such as moisture, concentration of CO2, and reaction time can affect CO2\ncapture performance of fly ash. Due to a short diffusion length of H2CO3 in water, the semi-dry\nprocess exhibits faster carbonation reaction than the wet process. Especially, the semi-dry process\ndoes not require a wastewater treatment plant because it uses a small amount of water. This study\nmay have important implications, illustrating the possibility of replacing the wet process with the\nsemi-dry process....
In this paper, the use of solid-state reactions for the storing of thermal energy at high\ntemperature is proposed. The candidate reactions are eutectoid- and peritectoid-type transitions\nwhere all the components (reactants and reaction products) are in the solid state. To the best of our\nknowledge, these classes of reactions have not been considered so far for application in thermal\nenergy storage. This study includes the theoretical investigation, based on the Calphad method, of\nbinary metals and salts systems that allowed to determine the thermodynamic properties of interest\nsuch as the enthalpy, the free energy, the temperature of transition, the volume expansion and the\nheat capacity, giving guidelines for the selection of the most promising materials in view of their\nuse for thermal energy storage applications. The theoretical investigation carried out allowed the\nselection of several promising candidates, in a wide range of temperatures (300â??800 Degree Celsius). Moreover,\nthe preliminary experimental study and results of the binary Mn-Ni metallic system are reported. This\nsystem showed a complex reacting behavior with several discrepancies between the theoretical phase\ndiagram and the experimental results regarding the type of reaction, the transition temperatures and\nenthalpies and the final products. The discrepancies observed could be due both to the synthesis\nmethod applied and to the high sensitivity of the material leading to partial or total oxidation upon\nheating even if in presence of small amount of oxygen (at the ppm level)...
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