• 한국유체기계학회 논문집
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• 제2권4호
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• pp.40-47
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• 1999

A hot water layer (HWL hereinafter) was installed at the depth of 1.2 m from the pool surface to reduce the radiation level at the pool top. After the HWL system was improved by the replacement of the filter with the Ion Exchanger to capture the Na-24, to purify the pool water of HWL and finally to reduce the radiation at the pool top. It was confirmed by the performance test of the pump and the measurement of the pressure difference through the Ion Exchanger and the strainer, that the flow characteristics of HWL system was not adversely affected after the system modification. Also the flow analysis using the pressure loss coefficients of the Ion Exchanger and strainer, calculated by the Darcy formula, could predict the flow variations by pressure changes within $10\%$ error in comparison with the field test results. It was also confirmed that HWL was maintained with the depth of 1.2 m from the pool surface because each electric water heater was electrically and thermodynamically maintained at 30 kW and the temperature of HWL was maintained with $5^{\circ}C$ higher temperature than that of pool water. Finally, it was confirmed that the pool top radiation was saturated and stabilized below 10000 nG/hr within 24 hours as the ion exchanger captured the main nucleus, Na-24 and purified the pool water of HWL.

• 대한설비공학회지:설비저널
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• 제14권1호
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• pp.21-30
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• 1985

One of the problems with the Boiling Water Reactor involves the flow and thermal mixings in the suppression water pool high pressure steam discharge into the pool in case of emergency core relief. Varioos heat sensitive devices and pumps for the reactor core cooling are installed in the middle of the suppression pool. Especially the pumps utilize pool water in order to cool the reactor core in emergency cases. In this case, the water temperature for the reactor cool ins should be below a certain temperature specified by the reactor design. In the present investigation, in other to determine the optimum locations of these pumping devices, numerical solutions have been obtained for the model to determine the f low mixing characteristics. Experimental investigations have also been carried out for the flow mixing and for the thermal mixing in the pool during the discharge. Considering that the discharge steam through the Quenching Device becomes hot water immediately in the water pool, the steam- equivalent hot water has been utilized. Examining these characteristices, it becomes possible to deform me the best locations for RCIC, LPCI , HPCI pumps in the suppression water pool for the emermency reactor core cooling.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2204-2220
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• 2020

An open-pool type research reactor is designed and operated considering the accessibility around the pool top area to enhance the reactor utilization. The reactor structure assembly is placed at the bottom of the pool and filled with water as a primary coolant for the core cooling and radiation shielding. Most radioactive materials are generated from the fuel assemblies in the reactor core and circulated with the primary coolant. If the primary coolant goes up to the pool surface, the radiation level increases around the working area near the top of the pool. Hence, the hot water layer is designed and formed at the upper part of the pool to suppress the rising of the primary coolant to the pool surface. The temperature gradient is established from the hot water layer to the primary coolant. As this temperature gradient suppresses the circulation of the primary coolant at the upper region of the pool, the radioactive primary coolant rising up directly to the pool surface is minimized. Water mixing between these layers is reduced because the hot water layer is formed above the primary coolant with a higher temperature. The radiation level above the pool surface area is maintained as low as reasonably achievable since the radioactive materials in the primary coolant are trapped under the hot water layer. The key to maintaining the stable hot water layer and keeping the radiation level low on the pool surface is to have a stable flow of the primary coolant. In the research reactor with a downward core flow, the primary coolant is dumped into the reactor pool and goes to the reactor core through the flow guide structure. Flow fields of the primary coolant at the lower region of the reactor pool are largely affected by the dumped primary coolant. Simple, circular, and duct type discharge headers are designed to control the flow fields and make the primary coolant flow stable in the reactor pool. In this research, flow fields of the primary coolant and hot water layer are numerically simulated in the reactor pool. The heat transfer rate, temperature, and velocity fields are taken into consideration to determine the formation of the stable hot water layer and primary coolant flow. The bulk Richardson number is used to evaluate the stability of the flow field. A duct type discharge header is finally chosen to dump the primary coolant into the reactor pool. The bulk Richardson number should be higher than 2.7 and the temperature of the hot water layer should be 1 ℃ higher than the temperature of the primary coolant to maintain the stability of the stratified thermal layer.

• 한국농공학회지
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• 제21권3호
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• pp.121-126
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• 1979

The objective of this study was to grasp the condition of the distribution of water temperature in the warm water pool, and these observations were performed in Wudu warm water pool located at Wodu-Dong in Chuncheon. The results summarized in this study are as follows; 1. The horizontal distribution charts of water temperature at each depth of points were shown as Fig. 3, Fig. 4, and Fig. 5, respectively. In consequence of the observation, the condition of warm water was stagnant in the coner of warm water pool. As the result, it was found out that stagnant condition was the heaviest at water surface (depth; 0.05m), more heavier at middle depth (depth; 0.55m) and some heavy at bottom of the pool (depth; 1.10m). 2. The vertical water temperature change was shown as Fig. 6, and the mean water temperature of water surface (depth;0.05m) was higher about $2.2{\sim}3.3^{\circ}C$ than bottom water temperature. 3. Therefore, it was required to device such structures as form of broad cannels or overflow diversion weirs to mingle with top and bottom water.

• 연구논문집
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• 통권25호
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• pp.129-135
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• 1995

This study discribes characteristics of water spray for extinguishment of gasoline pool fire. Experiments are carried out for the gasoline pool fire in a small tank with a diameter of 150mm and a height of 8mm. Droplet size, spray pressure, amount of water which reaches the flame base and velocity of water spray are measured to find extinguishment conditions and air entrainment due to the water spray is visualized. Critical conditions of water spray for extinguishment of gasoline pool fire is quantitatively shown.

• 에너지공학
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• 제25권2호
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• pp.45-51
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• 2016

연구용원자로에서 여러 수조 및 일차냉각계통 내부에 존재하는 냉각재를 정화시키기 위해 설치되는 수조수관리계통은 일차냉각계통 펌프가 정지한 후 원자로에서 발생하는 노심 붕괴열을 제거한다. 또한, 작업수조 내의 조사물과 사용후핵연료저장조 내에 저장된 사용후핵연료에서 발생하는 열을 제거하여 수조수의 온도를 제한 값 이내로 유지하는 기능도 수행한다. 본 연구에서는 수조수관리계통의 설계와 운전 방법을 설계 초기단계에서 결정하기 위해서 상용프로그램인 Flowmaster를 이용한 전산해석방법으로 수조수관리계통의 열교환기를 설계하고, 각 수조수의 온도를 시간에 따라 예측하였다.

• 대한설비공학회지:설비저널
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• 제17권4호
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• pp.499-507
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• 1988

The pressure suppression pool of BWR(Boiling Water Reactor) is subjected to hydrodynamic impact in the event of a LOCA(Loss of Coolant Accident). The pressure increase in the reactor dry cell would force the existing water of a vent pipe into the suppression pool. When the water is ejected through the pipe opening into the suppression pool, an abrupt downward force is transmitted to the suppression pool floor. Consequently, many structures installed within the pool must be able to withstand these forces. In order to determine the optimum safe locations of the pool structures, numerical analysis have been carried out to investigate the hydrodynamic behavior of the water jet. In the present analysis, a two-dimensional numerical model is utilized to solve transient flow equations.

• Ocean Systems Engineering
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• 제3권3호
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• pp.181-201
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• 2013

The main objective of this work is to investigate the sloshing behavior in a baffled and unbaffled three dimensional annular-sectored water pool (i.e., tank) which is located at dome region of the primary containment. Initially two case studies were performed for validation. In these case studies, the theoretical and experimental results were compared with numerical results and good agreement was found. After the validation of present numerical procedure, an annular-sectored water pool has been taken for numerical investigation. One sector is taken for analysis from the eight sectored water pool. The free surface is captured by Volume of Fluid (VOF) technique and the fluid portion is solved by finite volume method while the structure portions are solved by finite element approach. Baffled and un-baffled cases were compared to show the reduction in wave height under excitation. The complex mechanical interaction between the fluid and pool wall deformation is simulated using a partitioned strong fluid-structure coupling.

• 한국화재소방학회논문지
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• 제11권4호
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• pp.15-23
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• 1997

A series of measurements and visualization to investigate the extingushiment of water sprays with pool fires is presented. Fire source is a small-scale pool burner with methanol, ethanol and gasoline. Measurements of temperature, O2, CO2, and CO concentrations along the plume centerline are carried out to observe pool structures without water sprays. Visualization by the Ar-ion laser sheet flow pattern of droplets of the sprays above the pool fires. It is observed than in the case of methanol and ethanol, water sprays continuously penetrate into the center of fuel surfaces. The gasoline pool fire allows intermittent penetration of water sprays because of pulsating characteristics of the gasoline flame. To evaluate the cooling effect of the fuel surface by the sprays, the temperature was measured at the fuel surface. As soon as the mists reach the fuel surface of methanol and ethanol, the temperatures of the fuel surface decrease rapidly below the boiling point, and then the fires are extinguished. Due to the application of mist upon the gasoline fire, though the fuel temperature decrease abruptly at the time of the injection, such a repid decrease do not continue till the extinction point.

• 환경위생공학
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• 제4권1호
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• pp.37-42
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• 1989

Management of Swimming pool is focused on Swimming pool samitation in relation with chlorination of swimming water and potable water, disposal of waste and excrement within the boundry of swimming pool that may be summerised as follows: 1. Chlorination of Swimming Water Residual chlorine must be kept within the range of $0.4\~0.6 mg/l$ and in case of chloramine should be $0.7\~1.0mg/l$ while swimming pool is in operation 2. Chlorination of potable Water Residual chlorine must be kept within the rangs of $0.2\~04 mg/l$ at all time 3. Disposal of litters must be kept in the water tight waste bin with fitted lid, and waste should not be overflow -out of the bin. When waste in landfilled, the sufficient amount of cover material should be used daily. 4. Disposal of excrement Toilet must be water-flush type. However, The establishment of pit latrine is unavoidable the excrement must be covered with lime or dirt so that excrement should not be exposed to air.