• Nuclear Engineering and Technology
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• 제31권6호
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• pp.66-82
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• 1999

The national long-term R&D program, updated in 1997, requires Korea Atomic Energy Research Institute(KAERI) to complete by the year 2006 the basic design of Korea Advanced Liquid Metal Reactor(KALIMER), along with supporting R&D work, with the capability of resolving the issue of spent fuel storage as well as with significantly enhanced safety. KALIMER is a 150 MWe pool-type sodium cooled prototype reactor that uses metallic fuel. The conceptual design is currently under way to establish a self-consistent design meeting a set of major safety design requirements for accident prevention. Some of the current emphasis includes those for inherent and passive means of negative reactivity insertion and decay heat removal, high shutdown reliability, prevention of and protection from sodium chemical reaction, and high seismic margin, among others. All of these requirements affect the reactor design significantly and involve extensive supporting R&D programs. This paper summarizes some of the results of conceptual engineering and design analyses performed for the safety of HAMMER in the area of inherent safety, passive decay heat removal, sodium water reaction, and seismic isolation.

• 한국응급구조학회지
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• 제5권1호
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• pp.73-88
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• 2001

Post these safety tips in any swimming area for all swimmers to read. 1. Always swim with companions. Swim only in area well supervised by lifeguards. 2. Never drink alcohol or use drugs when you're swimming or boating. 3. Always check the water depth. Walk in from shore or ease in from the dock or the edge of the pool. 4. Know the limits of your own swimming abilities. If you're a good swimmer, don't tempt nonswimmers or beginner swimmers to try to keep up with you. 5. Keep any eye on younger swimmers at all times. 6. Learn the proper way to dive in the water safely. Follow guidelines for safe diving. 7. Follow the lifeguards instructions and respect their judgment. Never fake an Emergency. Obey all swimming rules.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.880-887
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• 1998

In order to study heat transfer characteristics of spray cooling for the purpose of uniform and soft cooling of high temperature surface a series of experiments for a hot horizontal copper flat plate was performed by downflow spray water using flat spray nozzle. Cooling curves were mea-sured under the various experimental conditions of flow rates and temperatures of cooling water Surface temperature surface heat fluxes and heat transfer coefficients of horizontal upward-facing flat surface were calculated with cooling curves measured at each radial positions near the cooling surface by TDMA method. Generally heat transfer characteristics for spray cooling is simi-lar to boiling phenomenon of pool boiling. The minimum heat flux(MHF) appear at the surface temperature of about ${\Delta}Tsat=250^{\circ}C$ and the critical heat flux(CHF) appear at about ${\Delta}Tsat=250^{\circ}C$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.721-727
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• 2000

Impedance method was carried out to design the electrode that can measure the void fraction of the bubbly flow in pool reservoir. To find out the optimum electrode shape, Styrofoam-tests were performed in a specially designed acrylic reservoir. Three kinds of electrodes were designed to compare the characteristics of water-air flow. The resistance was increased as the void fraction increased and the capacitance was decreased as the void fraction increased. The resistance is a main parameter to express the nature of the water-air flow in impedance method. Almost all the values of impedance were involved in resistance. The degree of deviation from the mean-resistance values showed reasonable results. Electrode type-I expressed excellent results among the three electrode shapes. The impedance values in void fraction 0-10% were similar to those of Maxwell's equation. But the impedance values in void fraction 10-20% were not similar to those of Maxwell' equation because of the edge effect near electrode.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.546-551
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• 1997

This paper presents a prediction of critical heat flux (CHF) in bubbly flow regime using dry-spot model proposed recently by authors for pool and flow boiling CHF and existing correlations for forced convective heat transfer coefficient, active site density and bubble departure diameter in nucleate boiling region. Without any empirical constants always present in earlier models, comparisons of the model predictions with experimental data for upward flow of water in vertical, uniformly-heated round tubes are performed and show a good agreement. The parametric trends of CHF have been explored with respect to variations in pressure, tube diameter and length, mass flux and inlet subcooling.

• 수산경영론집
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• 제46권3호
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• pp.129-141
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• 2015

Because land based aquaculture is restricted by high investment per rearing volume and control cost, good management planning is important in Land-based aquaculture system case. In this paper master production planning was made to decide the number of rearing, production schedule and efficient allocation of water resources considering biological and economic condition. The purpose of this article is to build the mathematical decision making model that finds the value of decision variable to maximize profit under the constraints. Stocking and harvesting decisions that are made by master production planning are affected by the price system, feed cost, labour cost, power cost and investment cost. To solve the proposed mathematical model, heuristic search algorithm is proposed. The model Input variables are (1) the fish price (2) the fish growth rate (3) critical standing corp (4) labour cost (5) power cost (6) feed coefficient (7) fixed cost. The model outputs are (1) number of rearing fish (2) sales price (3) efficient allocation of water pool.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.649-653
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• 2012

제방붕괴에 따른 피해발생을 억제하기 위해서는 제방거동 특성을 사전에 충분한 정보를 통하여 파악할 필요가 있으며, 이를 위해 광섬유를 이용한 제방누수감지 센서를 개발하였다. 광섬유는 내구성 및 유지관리가 우수하고 장기간 사용에도 장점을 가지고 있다. 개발된 센서들은 현장에 적용하기 전에 충분한 실험을 통해 성능과 기능에 대한 검토가 필요하다. 본 연구에서는 개발된 광섬유 센서를 대상으로 제방누수감지 목적으로 설치할 경우 센서의 이행도를 시험하였다. 시험방법은 토조를 설치하여 제체에 작용하는 간극수압, 온도 및 변위 등을 대상으로 하였다. 이를 위해 폭 5m, 길이 7m 및 높이 2m의 토조를 설치하여 가제방의 주요 부위에 기존 계측기기와 광섬유 센서를 같이 매설하고 수위와 시간변화에 따른 주요 특성치에 대하여 실험하였다. 실험결과 광섬유 센서가 연구목적에 부합하는 계측치를 보여주어 제방누수감지 센서로 활용 가능함을 확인하였다. 아울러 광섬유 센서의 기능에 대한 전반적인 실험을 통하여 현장적용에 대한 사용성을 입증하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.95-95
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• 2019

보를 월류하는 흐름은 유량에 따라 상이한 흐름특성을 보인다. 즉, 유량이 증가함에 따라 사류 (supercritical flow), 완전도수 (complete hydraulic jump), 수중도수 (submerged hydraulic jump), 그리고 잠긴흐름 (plunge pool)으로 천이한다. 각 흐름영역에 따른 하상전단응력의 변화는 보의 물받이와 하상보호공을 설계하는데 중요하다. 본 연구에서는 계산유체동역학을 이용하여 보를 월류하는 흐름을 수치모의하여 각 흐름의 수리적 특성을 분석하였다. 이를 위하여 Flow3D를 이용하여 RANS 방정식을 수치해석 하였으며, 난류모형으로 RNG $k-{\epsilon}$ 모형을 이용하였다. 수치모의를 통하여 각각의 흐름에 대하여 평균유속, 하상전단응력, 그리고 흐름저항계수의 종방향 분포를 제시하였다.

• 한국물환경학회지
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• 제27권2호
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• pp.218-227
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• 2011

The objective approach for assessment of stream naturalness is an essential part of the stream restoration project. This study proposes the methodology for the assessment of stream naturalness considering physical, biological and chemical factors. Physical factors consists of riffle and pool, river bed material, bank protection, floodplain vegetation and levee materials; biological factors are benthic macroinvertebrate, KSI (Korean Saprobic Index), and IBI (Index of Biological Integrity) and chemical factors are pH, DO (dissolved oxygen), and TP (total phosphorus). This procedure is applied to the Mokgamcheon. As a result, the downstream of Mokgamcheon (zone I) needs the prompt improvement of stream naturalness, compared to the others (zone II and III). This evaluation technique will be an effective tool to quantify the stream naturalness and can be used to set the target of stream restoration project.

• 생태와환경
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• 제49권4호
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• pp.320-333
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• 2016

본 연구는 2013년 4월 하순~5월 동안에 영산강의 승촌보 상류에서 군체형 녹조류 Eudorina elegans의 단일 종에 의해 유례없이 대발생한 녹조현상의 전개 과정을 모니터링하였다. 영산강은 전형적인 조절 하천으로서 외적 또는 내적 요인에 의한 부영양화가 극도로 심각한 실정이었다. 하수처리수의 과잉 영양염을 기반으로 유속, 일사량 및 수온의 구조적 또는 비구조적 복합 영향에 의한 조류(규조류(겨울), 녹조류(봄~여름) 및 남조류(여름))의 대발생은 뚜렷한 계절적 잠재력으로 상존하였다. 이 중에서 봄철 녹조현상은 E. elegans에 의한 것으로서 그 수준은 최대 $1,000mg\;m^{-3}$(>$50{\times}10^4cells\;mL^{-1}$)을 초과하였고, 발생 초기에 폭증하였다가 시간이 경과하면서 점진적으로 감소하는 양상이 현저하였다. 또한, 간헐적인 강우에 의해 하류로 이송되면서 분포 범위가 급속도로 확대되는 특성을 보였다. 보 구조물의 조작으로 펄스유량을 시험 적용하였으나 근본적인 문제를 해결하는 대응책은 아니었고, 하류 하천에 대한 영향을 고려해야 하는 문제점을 포함하고 있었다. E. elegans 녹조현상은 군체형 운동성 조류의 전형적 특성을 나타내었고, 최종적으로 후속되는 강우사상 (>45 mm)에 의해 소멸되었다.