• Title/Summary/Keyword: nuclear power engineering

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Cesium Radioisotope Measurement Method for Environmental Soil by Ammonium Molybdophosphate (환경토양에서 몰리브도인산 암모늄을 이용한 세슘 동위원소 평가방법)

  • Choe, Yeong-hun;Seo, Yang Gon
    • Clean Technology
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    • v.22 no.2
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    • pp.122-131
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    • 2016
  • Caesium radioisotopes, 134Cs and 137Cs which come from the atmospheric nuclear tests and discharges from nuclear power plants, are very important to study artificial radioactivity. In this work, in order to lower the minimum detection activity (MDA) we investigated environmental radioactivity according to the Environment Measurement Laboratory procedure by 137Cs and 134Cs which is similar to chemical and environmental behaviors of 137Cs. The environmental soils in high mountain areas near nuclear power plant were collected, and an Ammonium Molybdophosphate (AMP) precipitation method, which showed high selectivity toward Cs+ ions, was applied to chemically extract and concentrate Caesium radioisotopes. Radioactivity was estimated by a gamma-ray spectrometry. In gamma energy spectrum, with an increasing of 40K radioactivity, it increased the MDA of 134Cs and 137Cs. Therefore, if the natural radionuclides were removed from the soil samples, the MDA of Caesium may be reduced, and the contents of 137Cs of in the environmental soils can effectively be estimated. In the standard soil sample of Korea Institute of Nuclear Safety, radioactivity of 40K was removed more than 84% on average, and the MDA of 134Cs was reduced 2 times. The content of 137Cs was recovered over 84%. On the other hand, in environmental soils, AMP precipitation method showed removal ratio of 40K up to 180 times, which reduced the MDA about 5 times smaller than those of Direct method. 137Cs recovery ratio showed from 54.54% to 70.06%. When considering the MDA and recovery ratio, AMP precipitation method is effective for detection of Caesium radioisotopes in low concentration.

A Study on the Geomagnetic Reference Field Modeling from the Triaxial Magnetometer Data Onboard KOMPSAT-II (아리랑위성 2호의 삼축자력계로부터 관측된 지구자기장 모델 연구)

  • Kim, Hyung-Rae;Hwang, Jong-Sun;Kim, Jeong-Woo;Lee, Seon-Ho
    • Economic and Environmental Geology
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    • v.45 no.4
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    • pp.377-384
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    • 2012
  • The main field component of the Earth's magnetic field was modeled from the tri-axial magnetometer onboard KOrean MultiPurpose SATellite-II (KOMPSAT-II) for the purpose of satellite attitude control. The model computed by the KOMPSAT-II magnetometer measurement data is compared with the International Geomagnetic Reference Field (IGRF) model of a degree of up to 13 in spherical harmonic coefficients. The previous study with KOMPSAT-I (Kim et al. 2004) indicated a good correlation of power spectrum of spherical harmonic coefficients with respect to the degree up to 5. This study, however, showed an agreement of the degree up to 8-9 of the coefficient power spectrum and a discrepancy between degrees 10 and 13. We have concluded that relevant data selection process, removal of the external field from the data in the high latitude region, an accuracy of the magnetometer all play an important role in finding a coherence with the IGRF model. This study will be extended to the secular variation model of geomagnetism if longer-period data become available.

An historical analysis on the carbon lock-in of Korean electricity industry (한국 전력산업의 탄소고착에 대한 역사적 분석)

  • Chae, Yeoungjin;Roh, Keonki;Park, Jung-Gu
    • Journal of Energy Engineering
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    • v.23 no.2
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    • pp.125-148
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    • 2014
  • This paper performs a historical analysis on the various factors contributing to the current carbon lock-in of Korean electricity industry by using techo-institutional complex. The possibilities of the industry's carbon lock-out toward more sustainable development are also investigated. It turns out that market, firm, consumer, and government factors are all responsible for the development of the carbon lock-in of Korean power industry; the Korean government consistently favoring large power plants based on the economy of scale; below-cost electricity tariff; inflation policy to suppress increases in power price; rapid demand growth in summer and winter seasons; rigidities of electricity tariff; and expansion of gas-fired and imported coal-fired large power plants. On the other hand, except for nuclear power generation and smart grid, environment laws and new and renewable energy laws are the other remaining factors contributing to the carbon lock-out. Considering three key points that Korea is an export-oriented economy, the generation mix is the most critical factor to decide the amounts of carbon emission in the power industry, and the share of industry and commercial power consumption is over 85%, it is unlikely that Korea will achieve the carbon lock-out of power industry in the near future. Therefore, there are needs for more integrated approaches from market, firm, consumer, and government all together in order to achieve the carbon lock-out in the electricity industry. Firstly, from the market perspective, it is necessary to persue more active new and renewable energy penetration and to guarantee consumer choices by mitigating the incumbent's monopoly power as in the OECD countries. Secondly, from the firm perspective, the promotion of distributed energy system is urgent, which includes new and renewable resources and demand resources. Thirdly, from the consumer perspective, more green choices in the power tariff and customer awareness on the carbon lock-out are needed. Lastly, the government shall urgently improve power planning frameworks to include the various externalities that were not properly reflected in the past such as environmental and social conflict costs.

Approach to improve construction management using Information Technology (IT) (정보기술(IT) 기반을 통한 시공관리 선진화 방안)

  • Lee Woo-Bang;Moon Jin-Yeong;Moon Byeong-Suk
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • autumn
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    • pp.115-122
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    • 2002
  • There is various points that should be improved in Fairness such as our contract practice to propose construction projects, project managing and the stakeholders' way of thinking and culture. We consider that the revision of construction related provisions and systems is required but even more, an overall change in business management through the implementation of Integrated Construction Information Management System that will enable the owner, which drives the project, and contractor sharing construction information is required. To mange construction related information in an integrated manner, designing information should be smoothly transferred to purchasing information, and changes are required in order to move ahead to process-oriented work system. Finally information created from various construction organizations should be delivered in an aligned and standardized manner as well. The domestic Nuclear Power Plant Construction has been accepting various technology transfers from U.S, France, Canada and UK, which enabled us to self-support technology and recently even proceeded to the phase exporting our technology to others. However, continuous effort is required to improve internal business efficiency and to respond to external environmental change such aselectricity market deregulation. Recently, in accordance with the result in number of CEO's intention to make progress in IT and improve business efficiency, the number of enterprises introducing Enterprise Resource Planning is increasing. ERP is an innovative tool which changes the way of performing work from organization and department orientation to process-orientation in order to optimize the resources, such as human and material resources, through out the Enterprise by performing BPR which will maximize overall business efficiency of the enterprise, such includes not only construction management, but also business management. KHNP continued to performing large scaled construction projects such as nuclear power plant construction for past 30 years and took the initiatives of large scale project management and Quality management ability in domestic industry by having independent capability of over all construction planning, purchasing and, construction and start up management etc. To maintain our leading position of improving construction management technology based on our accumulated project management experience and technology, KHNP included construction into our ERP project in purpose of innovating construction business. We would like to discuss the characteristics of nuclear construction business, project management system, information system infrastructure and information sharing system among construction related entities, and implementation practices for information system, and consider how to resolve our practice that should be improved in this thesis.

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Evaluation of hydropower dam water supply capacity (II): estimation of water supply yield range of hydropower dams considering probabilistic inflow (발전용댐 이수능력 평가 연구(II): 확률론적 유입량을 고려한 발전용댐 용수공급능력 범위 산정)

  • Jeong, Gimoon;Kang, Doosun;Kim, Dong Hyun;Lee, Seung Oh;Kim, Taesoon
    • Journal of Korea Water Resources Association
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    • v.55 no.7
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    • pp.515-529
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    • 2022
  • Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams.

Radar-based rainfall prediction using generative adversarial network (적대적 생성 신경망을 이용한 레이더 기반 초단시간 강우예측)

  • Yoon, Seongsim;Shin, Hongjoon;Heo, Jae-Yeong
    • Journal of Korea Water Resources Association
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    • v.56 no.8
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    • pp.471-484
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    • 2023
  • Deep learning models based on generative adversarial neural networks are specialized in generating new information based on learned information. The deep generative models (DGMR) model developed by Google DeepMind is an generative adversarial neural network model that generates predictive radar images by learning complex patterns and relationships in large-scale radar image data. In this study, the DGMR model was trained using radar rainfall observation data from the Ministry of Environment, and rainfall prediction was performed using an generative adversarial neural network for a heavy rainfall case in August 2021, and the accuracy was compared with existing prediction techniques. The DGMR generally resembled the observed rainfall in terms of rainfall distribution in the first 60 minutes, but tended to predict a continuous development of rainfall in cases where strong rainfall occurred over the entire area. Statistical evaluation also showed that the DGMR method is an effective rainfall prediction method compared to other methods, with a critical success index of 0.57 to 0.79 and a mean absolute error of 0.57 to 1.36 mm in 1 hour advance prediction. However, the lack of diversity in the generated results sometimes reduces the prediction accuracy, so it is necessary to improve the diversity and to supplement it with rainfall data predicted by a physics-based numerical forecast model to improve the accuracy of the forecast for more than 2 hours in advance.

Fiber Optic Sensors for Smart Monitoring (스마트 모니터링용 광섬유센서)

  • Kim, Ki-Soo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.6 s.52
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    • pp.137-145
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    • 2006
  • Recently, the interests in structural monitoring of civil infrastructures are increased. Especially, as the civil infrastructures such as bridges, tunnels and buildings become large-scale, it is necessary to monitor and maintain the safety state of the structures, which requires smart systems that can supply long-term monitoring during the service time of the structures. In this paper, we investigated the possibilities of fiber optic sensor application to the various structures. We investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show good response to the structural behavior of the joint while electric gauges lack of sensitivity, durability and long term stability for continuous monitoring. We also apply fiber optic structural monitoring to the composite repaired concrete beam structure. Peel-out effects is detected with optical fiber Bragg grating sensors and the strain difference between main structure and repaired carbon sheets is observed when they separate each other. The real field test was performed to verify the behaviors of fiber Bragg grating sensors attached to the containment structure in Uljin nuclear power plant in Korea as a part of structural integrity test which demonstrates that the structural response of the non-prototype primary containment structures. The optical fiber Bragg grating sensor smart system which is the probable means for long term assessments can be applicable to monitoring of structural members in various civil infrastructures.

Effects of Geometry of Reactor Pressure Vessel Upper Head Control Rod Drive Mechanism Penetration Nozzles on J-Groove Weld Residual Stress (원자로 상부헤드 제어봉구동장치 관통노즐 형상이 J-Groove 용접잔류응력에 미치는 영향)

  • Kim, Ju-Hee;Kim, Yun-Jae;Lee, Sung-Ho;Hur, Nam-Young;Bae, Hong-Yeol;Oh, Chang-Young;Kim, Ji-Soo;Park, Heung-Bae;Lee, Seung-Geon;Kim, Jong-Sung;Huh, Nam-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.10
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    • pp.1337-1345
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    • 2011
  • In pressurized water reactors (PWRs), the reactor pressure vessel (RPV) upper head contains numerous control rod drive mechanism (CRDM) nozzles. In the last 10 years, the incidences of cracking in alloy 600 CRDM nozzles and their associated welds has increased significantly. Several axial and circumferential cracks have been found in CRDM nozzles in European PWRs and U.S. nuclear power plants. These cracks are caused by primary water stress corrosion cracking (PWSCC) and have been shown to be driven by welding residual stresses and operational stresses in the weld region. Therefore, detailed finite-element (FE) simulations for the Korea Nuclear Reactor Pressure Vessel have been conducted in order to predict the magnitudes of the weld residual stresses in the tube materials. In particular, the weld residual stress results are compared in terms for nozzle location, geometry factor$r_o$/t, geometry of fillet, and adjacent nozzle.

A Study on the Waste Treatment from a Nuclear Fuel Powder Conversion Plant (핵연료 분말제조 공정에서 발생하는 폐액의 처리에 관한 연구)

  • Jeong, Kyung-Chai;Kim, Tae-Joon;Choi, Jong-Hyun;Park, Jin-Ho;Hwang, Seong-Tae
    • Applied Chemistry for Engineering
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    • v.7 no.6
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    • pp.1164-1173
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    • 1996
  • Treating methods and characteristics of waste from a nuclear fuel powder conversion plant were studied. To recovery or treat a trace uranium in liquid waste, the ammonium uranyl carbonate(AUC) filtrate must be heated for $CO_2$ expelling, essentially. Uranium content of final treated waste solution from fuel powder processes for a heavy water reactor(HWR) could be lowered to 1 ppm by the lime treatment after the ammonium di-uranate(ADU) precipitation by simple heating. Otherwise, in case of the waste from fuel powder processes for a pressurized light water reactor(PWR), it is result in 0.8 ppm as a form of uranium peroxide such as $UO_4{\cdot}2NH_4F$ compounds. Optimum condition was found at $101^{\circ}C$ by the simple heating method in case of HWR powder process waste. And in case of PWR powder process waste, optimum condition could be obtained by precipitating with adding hydrogen peroxide and adjusting at pH 9.5 with ammonia gas at $60^{\circ}C$ after heating the waste In order to expelling $CO_2$. As the characteristics of recovered uranium compounds, median particle size of ADU was increased with pH increasing in case of HWP waste. Also, in case of uranium proxide compound recovered from PWR waste, the property of $U_3O_8$ power obtained after thermal treatment in air atmosphere was similar to that of the powder prepared from AUC conversion plant.

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Development of the HEMP Generation, Propagation Analysis, and Optimal Shelter Design Tool (고 고도 전자기파(HEMP) 발생과 전파해석 및 방호실 최적 설계 Tool 개발)

  • Kim, Dong Il;Min, Gyeong Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2331-2338
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    • 2014
  • The HEMP threat may have acquired new, and urgent, relevance as the proliferation of nuclear weapons and missile technology accelerates of the North Korea, for example, is assessed as already having developed few atomic weapons, and is on the verge of North Korea already has missiles capable of delivering a nuclear warhead against South Korea. ITU K.78, K81 and IEC recommended its counter-measuring for the industrial facilities with navigation and sailing facilities in order to obviate the all of processor equipped system malfunctions from the EMP/HEMP but its simulation must only be done by the computer simulation which had studied on the 1960-1990 years USA/AFWL papers. This result has a significant activities to the South Korea being under the North Korea threat because all of HEMP related products was strongly limited for export. The HEMP cord which was developed newly by the KTI including the HEMP generation & propagation analysis, optimal shelter design tool, essential EM energy attenuation in multi-layered various soils and rocks and HEMP filter design tool. Especially, the least square fitting method was adopted to analysis for the EM energy attenuation in the soils and rocks because it has a various characteristics based on the many times field test reports.