• Nuclear Engineering and Technology
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• 제52권5호
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• pp.964-974
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• 2020

The small modular reactors (SMRs) of the integrated pressurized water reactor (IPWR) type have been widely developed owing to their enhanced safety features. The SMR-IPWR adopts passive residual heat removal system (PRHRS) to extract residual heat from the core. Because the PRHRS removes the residual heat using the latent heat of the water stored in the emergency cooldown tank, the PRHRS gradually loses its cooling capacity after the stored water is depleted. A quick restoration of the power supply is expected infeasible under station blackout accident condition, so an advanced PRHRS is needed to ensure an extended grace period. In this study, an advanced design is proposed to indirectly incorporate a dry air cooling tower to the PRHRS through an intermediate loop called indefinite PRHRS. The feasibility of the indefinite PRHRS was assessed through a long-term transient simulation using the MARS-KS code. The indefinite PRHRS is expected to remove the residual heat without depleting the stored water. The effect of the environmental temperature on the indefinite PRHRS was confirmed by parametric analysis using comparative simulations with different environmental temperatures.

• 플랜트 저널
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• 제14권4호
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• pp.33-38
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• 2018

본 연구에서는 복합화력발전소 백연방지 냉각탑의 동계운전시 백연발생을 방지하는 냉각수의 충전재 바이패스 비율이 설계치와 일치하는지에 대해 연구하였다. 29 Gcal/h 냉각용량인 백연방지 냉각탑의 운전 설계 습구온도는 $13^{\circ}C$에서 $-20^{\circ}C$ 범위이며, 이때 충전재 바이패스 비율 설계치는 0%에서 78 %로서, 외기온도 강하시 바이패스 비율 증가는 $2.36%/^{\circ}C$ 였다 발전소 정상운전 조건에서 냉각탑 유입공기의 습구온도가 $7.8^{\circ}C$에서 $-11.8^{\circ}C$ 범위에서의 실제 운전시 벡연방지를 위한 충전재 바이패스 비율은 23.8 %에서 74.3 % 범위로 측정되었다. 이때, 외기 습구온도 $7.8^{\circ}C$에서 $-9.55^{\circ}C$ 범위에서의 바이패스 비율 증가는 $2.71%/^{\circ}C$ 이었으며, 혹한기의 습구온도 $-10^{\circ}C$ 이하에서는 대기온도 강하에 따라 바이패스 비율 증가는 $1.61%/^{\circ}C$로 설계 대비 충전재 바이패스 비율 증가율이 감소되었음을 확인 하였다.

• 한국유체기계학회 논문집
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• 제5권4호
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• pp.26-31
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• 2002

The heat produced by the fission in the fuel of HANARO, 30 MW of research reactor, was transferred from the primary cooling water to the secondary cooling water through heat exchangers. The secondary cooling water absorbing the heat was circulated by secondary cooling pumps and cooled through 33 MW of cooling tower. Each capacity of the three secondary cooling pumps was fifty percent ($50\%$) of full load. The two pumps were normally operated and the other pump was standby. One of the secondary cooling pumps has often made troubles by high vibration. To release these troubles the pump shaft has been re-aligned, the pump bearing has been replaced with new one, the shaft sleeve has been replaced with new one, the shaft and the impeller have been re-balanced representatively and/or the vibration of motor has been tested by disconnecting the shaft of pump. But the high vibration of pump cannot be cleared. We find out the weight balance trouble of the assembly in which the impeller is installed in the shaft. After clearing the trouble, the high vibration is relieved and the pump is operated smoothly. In this paper, the trouble solution shooting method of secondary cooling pump is described including the reason of high vibration

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.197-202
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• 2001

The heat produced by the fission in the fuel of HANARO, 30 MW of research reactor, was transferred from the primary cooling water to the secondary cooling water through heat exchangers. The secondary cooling water absorbed the heat was circulated by secondary cooling pumps and cooled through 33 MW of cooling tower. Each capacity of the three secondary cooling pumps was fifty percent ($50\%$) of full load. The two pumps were normally operated and the other pump was standby. One of the secondary cooling pumps has often get troubles by high vibration. To release these troubles the pump shaft has been re-aligned, the pump bearing has been replaced with new one, the shaft sleeve has been replaced with new one, the shaft and the impeller have been re-weight balanced representatively or the vibration of motor has been tested by disconnecting the shaft of pump. But the high vibration of pump cannot be cleared. We find out the weight balance trouble of the assembly that the impeller is installed in the shaft. After clearing the trouble, the high vibration is released and the pump is operated with smooth. In this paper the trouble solution of secondary cooling pump is described including the reason of high vibration.

• 한국지열·수열에너지학회논문집
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• 제3권1호
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• pp.23-29
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• 2007

For the perfomance test of geothermal system, a large pilot of capacity of 50RT is built and operated in office building. This system is planed hybrid system with cooling tower as asisstance heat sink. From October, 2004 to September, 2005, this system is operated andmonitored. As the result, COP of heating periods is about 3.46 and COP of cooling periods is about 4.1. Therefore, geothermal system is useful and suitable in Korea.

• 설비공학논문집
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• 제18권11호
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• pp.923-932
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• 2006

In this paper, reentering ratio and cooling capacity of individual cooling towers arrayed on a building roof were studied by a numerical method. The number of 16 cooling towers were divided into 4 banks. It was considered the summer prevailing wind characteristics as west wind and south wind of 5 m/s. It was also considered the roofwall types as the curtainwall and the louverwall that had the outdoor air intake louver in the curtainwall. In this case, the louver was suggested as the solution that could prevent reentering phenomenon due to recirculation and interference of the discharge air. In the case of the curtainwall, the averaged reentering ratio are predicted 13.3% and 24.4% for the west and south wind of 5 m/s, respectively. In the case of the louverwall, the averaged reentering ratio are predicted 2.5% and 9.7% for the west and south wind of 5 m/s, respectively. Therefore, the louverwall is a appropriate solution for reducing the reentering phenomenon.

• 설비공학논문집
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• 제21권8호
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• pp.433-438
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• 2009

Experimental results for performance characteristics of small $NH_3$ absorption chiller/ heater are presented. The apparatus consists of 7RT water-cooled absorption system, solution pump, boiler, cooling tower and peripheral devices. The effect of experimental parameters, such as refrigerant mass flow rate, solution mass flow rate and cooling water temperature have been investigated in view of the system performance. The capacity of each heat exchanger increased as refrigerant mass flow rate increased in cooling mode. Also, a cooling capacity increased as a strong solution mass flow rate increased. The cooling and heating COP show 0.5, 1.5 regardless of refrigerant mass flow rate, respectively. The results focus on the evaluation for performance characteristics of system with respect to variation of refrigerant mass flow rate under standard design conditions.

• 한국전산유체공학회지
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• 제17권4호
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• pp.1-8
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• 2012

During a reactor normal operation, two parallel 50% capacity cooling pumps circulate primary coolant to remove the fission reaction heat of the reactor through heat exchangers cold by a cooling tower. When one pump is failure, the other pump shall continuously circulate the coolant to remove the residual heat generated by the fuels loaded in the reactor after reactor shutdown. It is necessary to estimate how much flow rate will be supplied to remove the residual heat. We carried out a flow network analysis for the parallel primary pumps based on the piping network of the primary cooling system in HANARO. As result, it is estimated that the flow rate of one pump increased about 1.33 times the rated flow of one pump and was maintained within the limit of the cavitation critical flow.

• 공업화학
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• 제20권4호
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• pp.391-395
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• 2009

폐목재의 에너지 전환을 위하여 2톤/일 규모의 고정층 가스화기($0.9m{\times}2.4m$)를 제작하여 실험하였다. 고정층 가스화 설비는 3~5 cm의 목재칩을 이용하였으며 하부에는 회전식 스토커가 설치되어있다. 목재칩 연료 투입은 다단 나이프밸브 방식으로 되어 있으며 관성력 집진설비, 가스냉각용 열교환기, ID Fan 및 Cooling tower 등으로 구성되어져 있다. 가스화기는 $700{\sim}1000^{\circ}C$ 사이에서 조업하였으며 CO: 25~40 vol%, $H_2$: 7~12 vol%, $CH_4$: 2~4 vol%, $CO_2$: 12~24 vol%의 조성을 가지는 합성가스가 생성되었다. 합성가스 발열량은 $1100{\sim}1500kcal/Nm^3$으로 나타나 공업로의 적용이 가능하였다. 또한 합성가스의 가스 엔진을 통한 전력 생산도 가능하여 1~4 kW의 전력을 생산하였다.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.773-780
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• 2009

The facility equipments generate dynamic force on building floor and the force can be measured with force transducer. However, this method depends on the measuring capacity or range of sensor, or mounts installation condition of equipments. Because of this restricting condition on force measuring system, this paper suggests a indirect method, the TPA(transfer path analysis) method, that produces a closely approximate dynamic force of equipments. This method calculates the dynamic force by using transfer response function. Firstly, the calculated dynamic force of impact load and continuous load was respectively compared with the sensor-measured value to examine the accuracy of TPA method. After that, the dynamic force and response induced by large facility equipments - a cooling tower, AHU and a large ventilator - were calculated by TPA method and the validity of these value were examined.