• Nuclear Engineering and Technology
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• 제55권2호
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• pp.640-647
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• 2023

Material corrosion in nuclear power plant (NPP) is not controlled only by amine injection but also by ion exchange (IX) which is the best option to remove trace Na⁺. This study was conducted to understand the Na⁺ leakage characteristics of IX beds packed with ethanolamine-form (ETAH-form) and hydrogen-form (H-form) resins in the simulated water-steam cycle in terms of intrinsic behaviors of four kinds of cation-exchange resins through ASTM test and Vanselow mass action modeling. Na⁺ was inappreciably escaped throughout the channel created in resin layer. Na⁺ leakage from IX bed was non-linearly raised because of its decreasing selectivity with increasing Na⁺ capture and with increasing the fraction of ETAH-form resin. Na⁺ did not reach the breakthrough earlier than ETAH⁺ and NH₄⁺ due to the increased selectivity of Na⁺ to the cation-exchange resin (H⁺ < ETAH⁺ < NH₄⁺ ≪ Na⁺) at the feed composition. Na⁺ leakage from the resin bed filled with small particles was decreased due to the enhanced dynamic IX processes, regardless of its low selectivity. Thus, the particle size is a predominant factor among intrinsic properties of IX resin to reduce Na⁺ leakage from the condensate polishing plant (CPP) in NPPs.

• 한국기계가공학회지
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• 제5권4호
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• pp.7-12
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• 2006

Galvanized steel pipe, copper pipe and stainless steel pipe, which is being used in waterworks piping materials. In case of galvanized steel pipe, the precipitation of a product is being generated due to the pollution of the tap water, a white water phenomenon, and various corrosion reaction because a zinc ion is melted by tap water. And in case of a cupper pipe, many problems which is harm in sanitation appeared because of a inflow of harmfulness substance by a frequent accident of a water leakage. So, to prevent these problems, it is substituted for stainless steel pipe. However, those problems is still occurring because of badness of welding, a problem of a water leakage in connection part, and a increment of construction expenses. Therefore, this research has examined the laying period according to each piping thickness and a corrosion shape according to each laying depth after laying in various soils(sandy loam, loamy, clay loam, clay) using galvanized steel pipe, copper pipe, and stainless steel pipe. That is, we has studied the data which is necessary for a rational method of preserving the quality of water by examining the corrosion properties of piping materials in the soil environment which waterworks piping materials is being used.

• 한국구조물진단유지관리공학회 논문집
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• 제24권5호
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• pp.61-68
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• 2020

본 연구에서는 지하 콘크리트 구조물의 누수 균열에 사용되는 주입형 누수보수재료의 품질관리 방안으로 규격화된 국제표준 ISO TS 16774 ｢Part 3 Test method for water(wash out) resistance｣와 KS F 4935 ｢점착유연형 고무 아스팔트계 누수보수용 주입형 실링재｣를 이용하여 현재 우리나라 누수보수현장에서 사용하고 있는 주입형 누수보수재료 5계열(합성고무계, 시멘트계, 아크릴계, 에폭시계, 우레탄계) 3종류씩, 총 15종류의 보수재료에 대한 지하 콘크리트 구조물이 처한 지하수의 유동성에 관한 유실 대응력의 안정성을 연구·검토하였다. 그 결과, KS F 4935 규격에서 규정하고 있는 "질량 변화율이 -0.1% 이내"의 성능 기준으로 고찰하면 합성고무계 RG-2, 우레탄계의 UG-1을 제외하고 나머지 13Type 보수재료는 다소 지하수의 유동성에 따른 유실 저항력의 안정화 방안 검토가 필요 할 것으로 판단된다. 본 연구 결과는 콘크리트 구조물의 균열 부위에 사용되는 보수재료의 선정에 있어 기본 지표로 사용가능 할 것으로 판단된다. 또한, 추후에 연구 개발 되는 보수재료의 품질 향상에 반영할 수 있는 기준 자료의 활용을 기대할 수 있다.

• Tribology and Lubricants
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• 제25권3호
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• pp.187-191
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• 2009

A leakage performance test and an endurance performance test of a 75 ton class turbopump mechanical face seal are performed using water under high speed and high temperature environment. A prototype mechanical face seal is manufactured for the purpose of sealing of fuel between a fuel pump and turbine. By simulating operating condition experimentally, the leakage rate and seal carbon wear rate are obtained to evaluate the performance of the prototype mechanical face seal. The test results show the acceptable leakage performance and reasonable wear tendency as well.

• 한국터널지하공간학회 논문집
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• 제10권3호
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• pp.257-267
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• 2008

우리나라에서 흔히 채택하고 있는 배수형 터널은 배수시스템 열화 혹은 수압작용에 따라 누수가 발생하는 문제점을 내포하고 있다. 누수는 소량일 경우 외관으로 드러나지 않아, 육안으로 확인할 단계가 되면 이미 라이닝 손상 혹은 설비에 영향을 미치는 상황이 되어 초기에 인지하고 대책을 마련하는 것이 매우 중요하다. 그러나 운영 중인 배수터널의 누수거동을 확인하기 위해서는 터널을 훼손하여 배면을 조사하여야 하는데, 이는 터널 유지관리상 허용되기 어렵다. 본 연구에서는 비파괴 물리탐사법인 전기비저항 탐사법을 이용하여 터널의 방수막을 훼손하지 않고, 누수여부를 파악하는 새로운 시도를 하였다. 모형 라이닝을 제작하여 습윤정도, 혹은 열화에 따른 누수거동을 탐사한 결과 전기비저항 탐사법이 라이팅 배수기능모니터링 혹은 누수조사에 유용하게 활용될 수 있음을 확인하였다. 또한 이 방법은 라이닝 누수 보수공사 후, 추가 누수여부의 조사 및 보수공사 점검에도 유용하게 활용될 수 있음을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.36-41
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• 2003

This paper presents the results of power spectra using the fundamental and low frequency harmonic components of leakage current waveform to study aging on contaminated EPDM insulator(was serviced during 1997-2001, region Pohang, korea) under salt fog conditions. Experiments have been conducted in the chamber salt fog and at the 16KVrms. The salt contents adjusted as 0g,25g,50g and 75g per liter of deionized water. The onset of dry-band arcing on polymer insulators could be determined by signal processing the low frequency harmonics components. A correlation has been found between the fundamental and low harmonic components of power spectra on leakage current. Where aging could be associated with an increase in the level of both the fundamental and low frequency harmonics components of leakage current. Surface aging for contaminated EPDM insulators occurred when the fundamental component of leakage current was greater then some level On the other hand, when the polymer insulator approached failure, the fundamental component of leakage current reached relatively high values and low frequency harmonics components of the leakage current trended to decrease. The results suggest that both the fundamental and low frequency harmonics of leakage current can be used as a tool to determine both the beginning of aging and before flashover, end of life EPBM insulator in salt fog.

• 대한심미치과학회지
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• 제4권1호
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• pp.12-22
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• 1995

The purposes of this study were to compare the bleaching efficacy of sodium perborate when mixed either with Superoxol or distilled water and to evaluate the efficacy of different location of intracoronal base on the presence of apical leakage of tested bleaching agents. Forty eight extracted human permanent incisors were stained via whole blood and canal fillings with conventional gutta percha were performed after routine biomechanical perparations. The experimental intracoronal base was placed either at the cementoenamel junction(group 3, 4) or 2mm below cementoenamel junction(group 1, 2). Walking bleaching was performed by two different combinations of bleaching agents : sodium perborate with distilled water in group 1, 3 and sodium perbrate with Superoxol in group 2, 4. The roots of the teeth were evaluated for the presence of color change to assess the leakage of bleaching agents and the cervical one-thirds of the crown were evaluated for bleaching effect from the whiteness Indea calculated by spectrophotometer. The results were as follows : 1. At the end of 12 days, all the sample teeth demonstrated the increase of Whiteness Index at cervical 1/3 of crown although there were some minor differences among groups. 2. Regardless of location of the base, sodium perborate with superoxol(group 2, 4) showed better results in bleaching than the sodium perborate with distilled water(group 1, 3). 3. Bleaching agent leaked into the root area when the base was placed 2mm below cementoenamel junction but no leakage was found when the base was placed at the cementoenamel junction.

• Restorative Dentistry and Endodontics
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• 제18권1호
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• pp.145-155
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• 1993

The purposes of this study were to compare the bleaching efficacy of sodium perborate when mixed either with Superoxol or distilled water and to evaluate the efficacy of different location of intracoronal base on the presence of apical leakage of tested bleaching agents. Forty eight extracted human permanent incisors were stained via whole blood and canal fillings with conventional gutta percha were performed after routine biomechanical perparations. The experimental intracoronal base was placed either at the cementoenamel junction(group 3, 4) or 2mm below cementoenamel junction(group 1, 2). Walking bleaching was performed by two different combinations of bleaching agents : sodium perborate with distilled water in group 1, 3 and sodium perbrate with Superoxol in group 2, 4. The roots of the teeth were evaluated for the presence of color change to assess the leakage of bleaching agnets and the cervical one-thirds of the crown were evaluated for bleaching effect from the whiteness Indea calculated by spectrophotometer. The results were as follows : 1. At the end of 12 days, all the sample teeth demonstrated the increase of Whiteness Index at cervical 1/3 of crown although there were some minor differences among groups. 2. Regardless of location of the base, sodium perborate with superoxol)group 2, 4) showed better results in bleaching than the sodium perborate with distilled water(group 1, 3). 3. Bleaching agent leaked into the root area when the base was placed 2mm below cementoenamel junction but no leakage was found when the base was placed at the cementoenamel junction.

• 상하수도학회지
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• 제34권5호
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• pp.335-344
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• 2020

Due to global climate change, mega-droughts have occurred frequently. Since long-term droughts make it difficult to secure the water resources, water supply needs to be restricted in a reasonable manner. In the event of limited water supply, the waterworks need to develop a restricted water supply strategy. This study showed that analyzing daily water supply could be used to respond to the first stage of a drought. According to an analysis of Korea's major water authorities, there was about 7~21% of room for daily minimum water supply in case of a drought. Restricting the water supply by lowering pressure is a good strategy for local water authorities with high water leakage rate since leakage is inversely dependent with pressure. For this method, it is necessary to quantify water deficiency and pressure at each node using a simulation. Since DDA-based software is not possible to predict changes in demand at nodes with pressure reduction, WaterGEMS, a PDA software, was used to quantitatively predict water shortages and pressures at each node. Locations where water is deficient need to install booster pumps or to be dispatched with water tank truck and bottled water. Without these support, lowering pressure could not be an option for water works. This paper suggests a method for waterworks to plan a drought by lowering pressure to restrict water supply using daily water supply analysis and PDA based simulation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술.기술논문발표회
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• pp.91-95
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• 2004

Utilization of underground construction if increased by the large size ＆ skycraperlization of building recently. Therefore. waterproof dependence of underground construction is risen. However, water leakage was happened by rupture by concrete conduct, drying shrinkage. form tie. In underground environment soil class, degradation of waterproofing is showing to corrode by oil. An odious smell by oil, promotion evil of reinforcing rod corrosion, declination of durability can happen. Then, practical un degree of underground spare becomes low, Because oil or water permeates by construction by degradation to waterproof class corrode by oil, is considered to affect evil durability of construction.