• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1306-1310
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• 2009

The roughness coefficients were estimated by the Manning's equation for the measured stage and flow velocity of Bocheong stream basin in Kum river. The relationships between the estimated roughness coefficients and the geomorphologic factors were formulated by the linear, logarithmic, exponential and power type function, thereafter correlation equations were presented. The correlation analysis was performed between the measured stream length and the basin area of Bocheong stream basin by the linear, logarithmic, exponential and power type function, and correlation equation for the stream length was given. The roughness coefficient has strong correlationship with stream slope, but low correlation coefficients with stream length and basin area. For the correlationship with the roughness coefficients and the stream slope, the logarithmic type function has the smallest correlation coefficient, on the other hand, the exponential type function has the largest correlation coefficient. For the relationship between the stream length and the basin area, the correlation coefficient of the logarithmic type function shows the smallest value, linear type function shows the largest value.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.2122-2126
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• 2008

With the degradation of water quality and, at the same time increased water usage, the sources of high quality, for examples, river/stream, municipal reservoir, wells, artisan and surface water, are diminishing. Therefore, the importance of water quality has been emphasized over the years through publications and various literature sources. Even though considerable research has resulted in significant strides for providing interpretive information and mitigation strategies for improvement of waters, the quality of which is still questionable. This study aims to propose a completely independent self-contained system for purifying waters, solar-powered ozone generator. It is a semi-permanent and cost effective environmental solution. Functions of ozone treatment are: 1) to maintain oxidative flexibility, 2) remove harmful chemicals, wastes, and other substances, and 3) prevent epizootic microbial outbreaks. Recent advances in technology have allowed the development of the practical, self-contained and independent solar powered device. Solar electrical producing panels that charge batteries are the key to using these systems anywhere electrical power is not available. This paper invites the readers to examine the problem and consider the viable, proven solution the solar powered ozone purifying system. This paper also introduces basic concept and background of solar powered ozone generators and examine its feasibility for improving water quality in rivers and streams.

• Journal of Environmental Science International
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• 제24권3호
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• pp.275-280
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• 2015

In order to measure the Radionuclides and Concentration, the directly grinded land samples (river soil, pine leaves and mugwort) among the environment samples around the nuclear power plant were filled in a 450 mL Marinelli beaker and weighed to obtain the dry mass ratio of the samples. Then the background and land samples were measured for 80,000 sec. The analysis of the collected land samples showed that most of them contained less radiation nuclide than the detection minimum limit in the 'Ministry of Education, Science and Technology Public Notice No. 2010-32.'In others, the natural radionuclides $^{40}K$ were detected. Of the products of nuclear reaction discharged by a nuclear reaction, $^{134}Cs$ and $^{137}Cs$ are more easily detected, and their discharge sources can be traced using the relative ratio. Although the radioactive concentration in the vicinity of Kori Nuclear Power Plant, which is more than 1,100km away from Fukushima, the Japanese nuclear accident site, continuous monitoring is needed as the radionuclides can still be accumulated in the soil or animals and plants.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제14권5호
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• pp.1159-1166
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• 1994

This study presents the methodology for the performance analysis and prediction of small hydro power plants(SHP). Rainfall data are characterized to estimate the flow duration curve of SHP, using the cumulative density function of Weibull distribution. The model for the performance analysis of SHP is developed. Also, the performance characteristics of the existing Anheung Plant located in Han River basin are analyzed by using the developed model. As a result, it was found that the model is suitable to analyze the performance characteristics of existing SHP and to predict the primary design performance such as the design flowrate, capacity, rate of operation and annual electricity production of SHP.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.150-160
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• 2011

This study focuses on the Achard turbine, a vertical axis, cross-flow, marine current turbine module. Similar modules can be superposed to form towers. A marine or river hydropower farm consists of a cluster of barges, each gathering several parallel rows of towers, running in stabilized current. Two-dimensional numerical modelling is performed in a horizontal cross-section of all towers, using FLUENT and COMSOL Multiphysics. Numerical models validation with experimental results is performed through the velocity distribution, depicted by Acoustic Doppler Velocimetry, in the wake of the middle turbine within a farm model. As long as the numerical flow in the wake fits the experiments, the numerical results for the power coefficient (turbine efficiency) are trustworthy. The overall farm efficiency, with respect to the spatial arrangement of the towers, was depicted by 2D modelling of the unsteady flow inside the farm, using COMSOL Multiphysics. Rows of overlapping parallel towers ensure the increase of global efficiency of the farm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제28권4호
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• pp.42-48
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• 2014

Sewage treatment facilities can purify sewage enough to be send to river or sea water, that discharged from human life and industrial activities. In the sewage treatment process, we can get large amount of by-product energy resources and materials such as heat of sewage, digester gas and purified water etc., it can be utilized by applying various technologies thereby we can reduce energy consumption in the process. In this paper, it was analyzed using the data collected from the operational case study for the energy savings effect that can be obtained when using the digester gas, one of the by-product materials of sewage treatment process, for electric power generation. Cost of 623million won is an annual reduction of 4,032MWh corresponding 9% of the annual electricity consumption of the sewage treatment plant, such an alternative power generation using digester gas was proposed in this paper has been verified the feasibility of the proposed reduction of energy.

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.73-93
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• 2012

With an active structural involvement in spiral case structure (SCS) that is always the design and research focus of hydroelectric power plant (HPP), the compressible membrane sandwiched between steel spiral case and surrounding reinforced concrete was often assumed to be linear elastic material in conventional design analysis of SCS. Unfortunately considerable previous studies have proved that the foam material serving as membrane exhibits essentially nonlinear mechanical behavior. In order to clarify the effect of membrane (foam) material's nonlinear stress-strain behavior on SCS, this work performed a case study on SCS with a compressible membrane using the ABAQUS code after a sound calibration of the employed constitutive model describing foam material. In view of the successful capture of fitted stress-strain curve of test by the FEM program, we recommend an application and dissemination of the simulation technique employed in this work for membrane material description to structural designers of SCS. Even more important, the case study argues that taking into account the nonlinear stress-strain response of membrane material in loading process is definitely essential. However, we hold it unnecessary to consider the membrane material's hysteresis and additionally, employment of nonlinear elastic model for membrane material description is adequate to the structural design of SCS. Understanding and accepting these concepts will help to analyze and predict the structural performance of SCS more accurately in design effort.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.668-674
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• 2017

Experimental verification of boron species in fuel CRUD (Chalk River Unidentified Deposit) would provide essential and important information about the root cause of CRUD-induced power shifts (CIPS). To date, only bonaccordite and elemental boron were reported to exist in fuel CRUD in CIPS-troubled pressurized water reactor (PWR) cores and lithium tetraborate to exist in simulated PWR fuel CRUD from some autoclave tests. We have reevaluated previous analysis of similar threadlike crystals along with examining some similar threadlike crystals from CRUD samples collected from a PWR cycle that had no indications of CIPS. These threadlike crystals have a typical [Ni]/[Fe] atomic ratio of ~2 and similar crystal morphology as the one (bonaccordite) reported previously. In addition to electron diffraction study, we have applied electron energy loss spectroscopy to determine boron content in such a crystal and found a good agreement with that of bonaccordite. Surprisingly, such crystals seem to appear also on corroded surfaces of Alloy 600 that was exposed to simulated PWR primary water with a dissolved hydrogen level of $5mL\;H_2/kg\;H_2O$, but absent when exposed under $75mL\;H_2/kg\;H_2O$ condition. It remains to be verified as to what extent and in which chemical environment this phase would be formed in PWR primary systems.

• Water for future
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• 제14권4호
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• pp.19-26
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• 1981

The auto-and cross-correlation function, power spectrum, coherence function and Markov model are applied to investigate the statistical characteristics of discharge and each factor of water quality and the interrelation-ship between the variation of discharge and water quality factors. The analysis of discharge, dissolved oxygen and electric conductivity, which were only obtainable data at the Indogyo gagining station in the downstream of the Han River, clearly showed that they hace distinct period of 12 months and three different periods of 6, 4 and 3 months weaker than the former. The cross-correlation between the discharge and water quality(DO, COND) is rather weak and the crosscorrelation function has its peak at lag one. It is considered therefrom that the variation of discharge behaves on water quality facotrs with one day's difference. In the examination of linear regression model for the serial generation and predictive measures, discharge series is fit to first and second order Markov model and DO, COND to first order Markov model.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2021년도 학술발표회
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• pp.106-106
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• 2021

라오스 남능강 유역에는 현재 11개의 수력 발전 댐이 운영되고 있으며 최근에 설치된 댐을 제외하고는 오래전에 개발된 운영규정 곡선에 근거하여 운영하고 있다. 즉 댐의 증설에 따른 하천 유량의 변동과 발전소의 설비용량증설 등의 발전환경이 충분히 반영되지 못한 상태로 운영하고 있으며, 이로 인해 통합수자원 관리의 최적화 차원의 일환으로 최대 전력생산을 위한 새로운 저수지 운영규정 곡선 개발이 필요하게 되었다. 저수지 운영규정 곡선(reservoir operation rule curve)은 일반적으로 주어진 저수지의 규모와 저수지로의 유입량 그리고 발전소의 설비용량 등의 발전환경을 종합적으로 고려하여 연간 발전량을 최대로 생산할 수 있도록 최적화 기법 등을 활용하여 개발한다. 본 고에서는 이를 위해 범용적인 동적 계획법(Dynamic Programming:DP)프로그램인 CSUDP를 활용하여 최초의 최적 저수지 운영규정 곡선을 제시하고 이에 의한 발전량을 모의하기 위해 HEC-ResSim package를 활용하였으며, 최종적으로는 기존의 운영규정 곡선, 운영실적, 그리고 현장 운영자의 의견 등을 종합적으로 고려하여 댐 운영 시나리오(단독, 연결, 댐별 상업 발전 시기 등)별로 운영규정 곡선을 개발하고 라오스 정부(EdL)에 제시하였다.