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Probabilistic Safety Assessment of IR-360 for Station BlackOut Accident (SBO) and Determination of the Frequency of Occurrence
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor) ; Yousefpour, Faramarz (Supervisor) ; Karimi, Kave (Co-Advisor)
Abstract
Station Blackout (SBO) involves Loss of Offsite Power (LOOP) concurrent with failure of the onsiteemergency ac power system. Although SBO is a beyond designbasis accident, in recent years this accident attracts a lot of attention. Fukushima nuclear accident which was initiated by earthquake followedby tsunami led to a SBO accident. In this thesis, Probabilistic Safety Assessment (PSA) is applied to analyze SBO in IR-360 nuclear power plant and to compute its frequency. Meanwhile, weak points of the plant are identified in order to minimize the SBOprobability of occurrence. Fault tree method is used to evaluate emergency power system and offsite power system reliabilities. Common Cause...
Application of PSA Methods in the Reliability Analysis of EPSS of Busherhr NPP in case of Station Black Out
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor)
Abstract
LOOP accident is one of the most important accidents in NPPS and it leads to loss of power supply of the RCP pumps which are the main pumps of primary circuit. Subsequently trip of the rector occurs. In safety analysis, concerning worst conditions, assumes that after a small period of time, main generator of plant stops working and loss of AC power supply of all power plant loads including safety systems ocures. To control of this accident, it’s necessary to startup and load backup power supply system (EDGs) for at least one safety channels, if not, the accident moves forwards and becomes S.B.O accident which is more important accident that ends to core damage because of stops working of all...
Numerical study on water distribution in different layers of direct methanol fuel cells
, Article Journal of the Electrochemical Society ; Vol. 161, issue. 8 , 2014 , pp. E3110-E3124 ; ISSN: 00134651 ; Baghalha, M ; Sharif University of Technology
Abstract
In this paper, a two-dimensional, two-phase, isothermal model is presented to investigate the water transport characteristic and water distribution in a direct methanol fuel cell (DMFC) with emphasis on exploring the water distribution in different layers of DMFC. The liquid-gas two-phase mass transport in the porous anode and cathode is formulated based on multi-fluid model in porous media and water and methanol crossover through the membrane are considered with the effect of diffusion, electro-osmotic drag, and convection. The modeling results agree well with the three different experimental data in an extensive range of operation conditions. A parametric study is also performed to examine...
Effects of microhydrophobic porous layer on water distribution in polymer electrolyte membrane fuel cells
, Article Journal of Fuel Cell Science and Technology ; Vol. 11, Issue. 1 , 2014 ; ISSN: 1550-624X ; Roshandel, R ; Sharif University of Technology
Abstract
Performance of polymer electrolyte membrane fuel cells (PEMFC) at high current densities is limited to transport reactants and products. Furthermore, large amounts of water are generated and may be condensed due to the low temperature of the PEMFC. Development of a two-phase flow model is necessary in order to predict water flooding and its effects on the PEMFC performance. In this paper, a multiphase mixture model (M2) is used, accurately, to model two-phase transport in porous media of a PEMFC. The cathode side, which includes channel, gas diffusion layer (GDL), microporous layer (MPL), and catalyst layer (CL), is considered as the computational domain. A multidomain approach has been used...
Modeling and technical-economic optimization of electricity supply network by three photovoltaic systems
, Article Journal of Solar Energy Engineering, Transactions of the ASME ; Vol. 136, issue. 2 , 2014 ; ISSN: 0199-6231 ; Khodaparast, P ; Kateb, M ; Sharif University of Technology
Abstract
To attain an ongoing electricity economy, developing novel widespread electricity supply systems based on diverse energy resources are critically important. Several photovoltaic (PV) technologies exist, which cause various pathways to produce electricity from solar energy. This paper evaluates the competition between three influential solar technologies based on photovoltaic technique to find the optimal pathways for satisfying the electricity demand: (1) multicrystalline silicon; (2) copper, indium, gallium, and selenium (CIGS); and (3) multijunction. Besides the technical factors, there are other effective parameters such as cost, operability, feasibility, and capacity that should be...
Assessment of an optimized combination of Iranian power plants by environmental costs impact of carbon tax and fossil fuel price on longterm development of iranian electricity supply system
, Article Journal of Environmental Studies ; Vol. 40, issue. 2 , 2014 , p. 415-430 ; Farmad, M ; Aryanpur, V ; Shafiei, E ; Sharif University of Technology
Abstract
Despite the abundant renewable energy sources, the Iranian energy sector relies almost entirely on fossil fuel energy resources. Power sector is dominant source of CO2 emissions and responsible for about 35% of total CO2 emissions in the country. Additionally, long-term electricity demand of Iran is expected to grow quickly, which in turn requires extensive investment to meet the growing demand over the next decades. On the other hand, increasing domestic fossil fuel consumption had been a serious challenge due to high costs of oil and gas. Current study pays particular attention to the possible penetration rates of renewable electricity technologies and their implications for fossil fuel...