• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1667-1668
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• 2008

There are three main devices such as boiler producing steam, turbine driving generator and generator producing electricity. An electrical generator in power plant is driven and maintained its speed at rated by steam turbine which is coupled into generator directly. Turbine auxiliary devices such as condenser, deaerator, feed water heater, gland steam condenser, pump recirculation equipment, feed water pump, and so on should be operated well so that the steam turbine exert its maximum efficiency. There are many control loop such as hot well level and condenser recirculation, deaerator level, pegging steam pressure, feed water heater level, feed water pump recirculation. In this paper condenser level control and deaerator level control are going to be described.

• Current Optics and Photonics
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• v.1 no.2
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• pp.138-142
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• 2017

Terahertz (THz) generation by periodically-poled $KTiOPO_4$ (PPKTP) with a quasi-phase-matching scheme based on cascaded difference frequency generation (DFG) processes is theoretically analyzed. The cascaded Stokes interaction processes and the cascaded anti-Stokes interaction processes are investigated from coupled wave equations. THz intensities and quantum conversion efficiency are calculated. Compared with non-cascaded DFG processes, THz intensities from 10-order cascaded DFG processes are increased to 5.53. The quantum conversion efficiency of 479.4% in cascaded processes, which exceeds the Manley-Rowe limit, can be realized.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.179-182
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• 2002

XLPE compound have used for insulation of 22.9(kV) power cable. But tree retardant power cable has developed and is going to br used commonly. TR XLPE compound retard production and growth of water tree. In this paper, tensile strength, elongation at break, degree of crosslinking, lightning impulse test, AC breakdown test, cyclic aging for 14days and accelerated water treeing test of TR XLPE insulated power cable were examined according to the KEPCO buying spec. & AEIC CS 5-94 standards. before and after As the result, tensile strength, elongation at break and degree of crosslinking test results of TR XLPE insulation were higher than requirement values. After accelerated water treeing test for 120 days, 240 days and 360 days, AC breakdown voltages were not decreased for accelerated water treeing aging duration

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.413-421
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• 2012

This paper proposes the design and implementation of fluid flow generation system by using polypropylene(PP) water capture, which harvests electric energy from the kinetic energy of tidal current or water flow and drives the desired load, and applies it to the discharge drain of Hadong thermal power plant. This experimental system is composed of water captures, driving wheel, gear trains, 10[kW] synchronous generator, and three phase rectifying circuit which drives lamp load for test. The proposed water capturing system which is composed of water captures, rope and driving wheel, rotates as caterpillar according to water flow. This system is very easy to manufacture and more economical than another type of tidal current turbines such as conventional propeller and helical type. Also, we estimated the available fluid flow energy that can be extracted from the cooling water in discharge drain based on drain's cross-sectional area. Therefore, this paper confirms the validity of proposed fluid flow generation system with water captures and the possibility of its application for renewable energy generation in discharge drain of thermal power plant, from the obtained performance characteristic of this energy conversion system.

• Membrane and Water Treatment
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• v.13 no.6
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• pp.313-320
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• 2022

Theoretical calculation results are presented for the enhancement of the water mass flow rate through the hydrophobic micro/nano pores in the membrane respectively on the micrometer and nanometer scales. The water-pore wall interfacial slippage is considered. When the pore diameter is critically low (less than 1.82nm), the water flow in the nanopore is non-continuum and described by the nanoscale flow equation; Otherwise, the water flow is essentially multiscale consisting of both the adsorbed boundary layer flow and the intermediate continuum water flow, and it is described by the multiscale flow equation. For no wall slippage, the calculated water flow rate through the pore is very close to the classical hydrodynamic theory calculation if the pore diameter (d) is larger than 1.0nm, however it is considerably smaller than the conventional calculation if d is less than 1.0nm because of the non-continuum effect of the water film. When the driving power loss on the pore is larger than the critical value, the wall slippage occurs, and it results in the different scales of the enhancement of the water flow rate through the pore which are strongly dependent on both the pore diameter and the driving power loss on the pore. Both the pressure drop and the critical power loss on the pore for starting the wall slippage are also strongly dependent on the pore diameter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.3
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• pp.267-273
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• 2013

In order to provide effective operating conditions for the fan in a wet cooling tower with film fill, a new program to search for the minimum fan power was developed using a model of the optimal total annual cost of the tower based on Merkel's model. In addition, a type of design map for a cooling tower was also developed. The inlet water temperature and heat load were considered as key parameters. The present program was first validated using several typical examples. The results showed that for a given heat load, a three-dimensional graph of the fan power (z-axis), mass flux of air (x-axis, minimum fan power), and inlet water temperature (y-axis, maximum of minimum fan power) showed a saddle configuration. The minimum fan power increased as the heat load increased. The conventionally known fact that the most effective cooling tower operation coincides with a high inlet water temperature and low air flow rate can be replaced by the statement that there exists an optimum mass flux of air corresponding to a minimum fan power for a given inlet water temperature, regardless of the heat load.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.1
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• pp.73-87
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• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1162-1173
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• 2016

In this paper, we describe a physicomathematical model of the processes that occur in a sodium circuit with a variable flow cross-section in the case of a water leak into sodium. The application area for this technique includes the possibility of analyzing consequences of this leak as applied to sodium-water steam generators in fast neutron reactors. Hydrodynamic processes that occur in sodium circuits in the event of a water leak are described within the framework of a one-dimensional thermally nonequilibrium three-component gas-liquid flow model (sodium-hydrogen-sodium hydroxide). Consideration is given to the results of a mathematical modeling of experiments involving steam injection into the sodium loop of a circulation test facility. That was done by means of the computer code in which the proposed model had been implemented.

• Corrosion Science and Technology
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• v.9 no.5
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• pp.187-195
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• 2010

Hyper duplex stainless steels have been developed in Korea for the purpose of application to the seawater system of Korean nuclear power plants. This system supplies seawater to cooling water heat exchanger tubes, related pipes and chlorine injection system. In normal operation, seawater is supplied to heat exchanger through the exit of circulating water pump headers, and the heat exchanged sea water is extracted to the discharge pipes in circulating water system connected to the circulating water discharge lines. The high flow velocity of some part of seawater system in nuclear power plants accelerates damages of components. Therefore, high strength and high corrosion resistant steels need to be applied for this environment. Hyper duplex stainless steel (27Cr-7.0Ni-2.5Mo-3.2W-0.35N) has been newly developed in Korea and is being improved for applying to nuclear power plants. In this study, the physical & mechanical properties and corrosion resistance of newly developed materials are quantitatively evaluated in comparative to commercial stainless steels in other countries. The properties of weld & HAZ (heat affected zone) are analyzed and the best compositions are suggested. The optimum conditions in welding process are derived for ensuring the volume fraction of ferrite(${\alpha}$) and austenite(${\gamma}$) in HAZ and controlling weld cracks. For applying these materials to the seawater heat exchanger, CCT and CPT in weldments are measured. As a result of all experiments, it was found that the newly developed hyper duplex stainless steel WREMBA has higher corrosion resistance and mechanical properties than those of super austenitic stainless steels including welded area. It is expected to be a promising material for seawater systems of Korean nuclear power plants.

• Nuclear Engineering and Technology
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• v.44 no.3
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• pp.343-354
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• 2012

Primary water stress corrosion cracking (PWSCC) is a major safety concern in the nuclear power industry worldwide. PWSCC is known to initiate only in the condition in which sufficiently high tensile stress is applied to alloy 600 tube material or alloy 82/182 weld material in pressurized water reactor operating environments. However, it is still uncertain how much tensile stress is re-quired to generate PWSCC or what causes such high tensile stress. This study was performed to pre-dict the magnitude of weld residual stress and operating stress and compare it with previous experi-mental results for PWSCC initiation. For the study, a pressurizer safety nozzle was selected because it is reported to be vulnerable to PWSCC in overseas plants. The assessment was conducted by nu-merical analysis. Before performing stress analysis for plant conditions, a preliminary mock-up ana-lysis was done. The result of the preliminary analysis was validated by residual stress measurement in the mock-up. After verification of the analysis methodology, an analysis under plant conditions was conducted. The analysis results show that the stress level is not high enough to initiate PWSCC. If a plant is properly welded and operated, PWSCC is not likely to occur in the pressurizer safety nozzle.