• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.401-406
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• 1997

발전소 기동 및 저출력 운전시 원자력발전소(PWR) 터빈운전원(T/O)들은 증기발생기 수위제어를 위해 배전반(MCR)에 증기발생기 수위제어 관련 경험이 있는 운전원 3명 이상이 좁은 보드앞에서 각자 S/G A, B, C의 주요 파라미터들을 감시하며 수동운전하게 된다. 이렇게 운전원들이 많은 위험부담을 안고 수동운전하는 이유는 증기발생기 수위제어는 증기발생기 내부의 광역수위 측정범위가 약 14.2(m)이고, 주요 제어변수를 측정하는 협역수위는 약 3.2(m)로 매우 적어서 물의 Swell, Shrink 현상과 급수온도의 영향으로 제어하기 매우 어렵기 때문이다. 그러나 DCS(Distributed Control System)내의 한 부분인 공정감시제어를 위한 MMI(Man Machine Interface) Software를 사용하면 한사람이 증기발생기 수위제어 전 계통의 감시 및 제어가 가능하게 된다. 또한 과거나 현재의 변화 추이 및 문제점 분석은 물론, 계통의 결함 발생시 경보가 발생하여 경보발생 화면을 선택할 경우 어느 부분에서 결함이 발생했는지를 보여준다. 만약 이 화면을 운전원이 아닌 현장 Engineer가 보았을 경우는 결함부분의 확인 및 결함카드 보수가 가능하여 운전원들의 작업부담 감소와 이로 인한 다른 계통 점검 시간을 충분히 확보할 수 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.3
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• pp.198-202
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• 2002

Ethanolamine (ETA), instead of ammonia, increases pH in the secondary system water and inhibits the corrosion of iron, which improves the integrity of the steam generator tubes. The different physicochemical properties of ETA from ammonia provide the different effect on the dissolution and adsorption of corrosion products entering the steam generator and thus on the hideout returns of ionic impurities in the steam generator sludge pile. The objective of this study was to investigate those properties with increasing temperature. ETA is more adsorbed onto the iron oxides, which increases the solubility of them and also lowers the hideout returns due to the reduced impurities adsorbed.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.509-515
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• 1997

환상형 이중벽 증기발생기와 환상형 전자펌프 신개념을 개발하여 중간열교환계통과 소듐 배관이 없는 단순하고 밀집된 형태의 액체금속로인 SAILMER 노형 개념을 제안하였다. 금속핵연료를 사용하는 모듈형으로 증기발생기에서의 소듐과 물 반응사고에 대비한 연구와 제작기술을 제고시키면 이 노형은 경제성과 고유안전성을 동시에 구현할 수 있다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.230-231
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• 2004

경수로형 원자로의 증기 발생기 내부에 방사화 된 침적물을 smear paper로 시료를 채취한여 핵종 분석 및 화학조성을 분석하였다. 상용발전소의 증기 발생기 외부에서 발견된 고 준위 방사성물질의 화학 조성 분석은 극미세 성분분석기(EPMA)를 이용하였다. 본 시험에 사용한 EPMA(Electron Probe Micro Analyzer, SX-50R, CAMECA, Paris, France)는 고 방사능을 띤 조사 핵연료 및 재료 시험을 수행할 수 있도록 기기의 시편 stage 주위를 납과 텅스텐으로 차폐하여 시편의 방사능 세기가 $3.7{\times}10^{10}$ Bq까지 시험 가능한 기기이다.(중략)

• Nuclear Engineering and Technology
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• v.23 no.3
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• pp.299-305
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• 1991

Corrosive environment may be generated within steam generators from condenser cooling water in-leakage. Theoretical analysis of the accumulation of chloride as a sea water impurity is being carried out for the condenser cooling water used at YGN-1,2 nuclear power stations. Calculations have shown that highly concentrated chloride solution would be produced within the steam generators in the case of sea water in-leakage. Maximum allowable design condenser leak rate(0.5 gpm) leads chloride concentration of 2.3 ppm at steam generetor and 0.6 ppm at hotwell with the maximum blowdown rate and condensate purification. Concentration factor at steam generator is dependent only on both blowdoum rate and condensate purification efficiency as follows, Concentration Factor（equation omitted）(B$\neq$O) Blowdown and condensate purification are evaluated as the only effective measures to remove impurities from the secondary systems.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.99-107
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• 2014

In this study, the effects of curing procedures on the mechanical properties of recycled aggregate concrete (RAC) were investigated. The replacement ratios by recycled coarse aggregate were 0, 25, 50, 75 and 100% by mass of natural coarse aggregate. Steam curing was adopted to all recycled aggregate concrete mixtures. Compressive and split tensile strength, water porosity, chloride ions penetration resistance and drying shrinkage measurements were carried out to determine performance of the RACs. From the test results, it was found that the mechanical performance of RAC decreased as the recycled aggregate contents increased. Furthermore, steam curing reduced the compressive and split tensile strength, water porosity and total charge of RAC, especially at the early ages. However, at the later ages, the beneficial effect of steam curing was less prominent. This study clearly showed that initial steam curing could be one of practical methods to improve performance of RAC with higher replacement ratio of recycled aggregate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.685-690
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• 2008

In numerically evaluating the thermal performance of the heat exchanger, numerical values of thermodynamic properties such as temperature, pressure, specific volume, enthalpy and entropy are required. But the steam table or diagram itself cannot be directly used without modelling. In this study the applicability of neural networks in modelling superheated water vapor was examined. The multi-layer neural networks consist of an input layer with 2 nodes, two hidden layers with 15 and 25 nodes respectively and an output layer with 3 nodes. Quadratic spline interpolation was also applied for comparison. Neural networks model revealed smaller percentage error compared with spline interpolation. From this result, it is confirmed that the neural networks could be a powerful method in modelling the superheated water vapor.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.255-259
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• 2022

Solar membrane steam generation is a very promising technology that can harvest purified water from seawater or wastewater during the current danger of running out of pure water. However, solar Membrane steam generation had direct contact with water, making it difficult to increase the efficient amount of evaporation. Here, we propose solar membrane steam generator composed of polydimethylsiloxane (PDMS) and graphene oxide (GO) and improved evaporation through wettability control in part throughout the water-absorbing membrane. Wettability control has shown significant improvements in thermal localization and temperature rise in the area of heat exchange with sunlight. The evaporator has an evaporation rate of 1.54 kg m^-2 h^-1 under 1 sun irradiation. The results showed that Solar membrane steam evaporation can effectively harvest pure water through an increase in evaporation.

• Membrane Journal
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• v.14 no.2
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• pp.157-165
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• 2004

PU/PDMS(Poly urethane/poly(dimethylsiloxane ) membranes were prepared to enhance chemical resistance over VOCs from 4,4'-diphenylmethane diisocyanate (MDI), poly(dimethylsiloxane) (PDHS). Swelling characteristics and vapor permeation performance of toluene, 1,2-dichloroethane, hexane through PU/PDMS membrane with various feed VOCs concentration were investigated. Swelling ratio of VOCs showed tendency of Toluene > 1,2-dichloroethane > hexane. Fiux of toluene and 1,2-dichloroethane increased with increasing fled concentration while the flux of hexane maintained with increasing feed. VOCs concentration in permeate maintained 50 wt% oi concentration due to high affinity of PU/PDHS membranes to VOCs.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.3
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• pp.179-189
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• 2014

Pyroprocessing has been developed for the purpose of resolving the current spent nuclear fuel management issue and enhancing the recycle of valuable resources. An electrolytic reduction of the pyroprocessing is a process to reduce oxides into metals using LiCl as an electrolyte and requires a post-treatment process due to the inclusion of residual salt in porous metal products. A vacuum distillation has been adopted for various molten salt systems and could be applied to the post-treatment process of the electrolytic reduction. The residual salt in the metal products includes LiCl, alkali chlorides, and alkaline earth chlorides. In this paper, vapor pressures of chlorides have been estimated and the composition changes on the residual liquid during the vacuum distillation process have been calculated. A model combining a material balance and vapor-liquid equilibrium relations has been proposed under a constant vapor discharging flow rate and liquid composition changes have been calculated using the vapor pressures with respect to a dimensionless time. The behaviors have been compared with temperature and molten salt composition changes to simulate the process condition variation. The distillation of the residual salt has been dominated by LiCl which is the main component of the salt and CsCl of which vapor pressure is higher than that of LiCl would be readily removed. RbCl exhibits similar vapor pressure with LiCl and maintains its composition. However, $SrCl_2$ and $BaCl_2$ of which vapor pressures are much lower than that of LiCl are concentrated with time and expected to be possibly precipitated during the distillation when the initial compositions are increased.