• 한국유체기계학회 논문집
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• 제15권4호
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• pp.5-11
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• 2012

To identify the flow characteristics of the SMART reactor, a flow distribution model test and a numerical simulation are performed in KAERI. Among several part of the SMART reactor, the fuel assemblies are simulated using simulators because of the complexity. The geometries of the core in the SMART reactor and simulator are different, but some similarities are maintained such as the ratio of pressure drop in the vertical and cross directions. There are cross flow holes in each core simulator to reproduce the cross flow of SMART fuel assemblies. To know the flow characteristics of the cross flow, numerical analysis is performed. As the cross flow area is decreased, the pressure drop between inlet and outlet is decreased. Also, when the flow imbalance between two core simulators is constant, the cross flow area does not significantly affect the cross flow.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2438-2446
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• 2023

To cool down a nuclear reactor core and prevent the fuel damage without a pump-driven active component during any anticipated accident, the passive emergency core cooling system (PECCS) was designed and adopted in an advanced light water reactor, i-POWER. In this study, for a validation of the cooling capability of PECCS, thermal-hydraulic integral effect tests were performed with the ATLAS facility by simulating intermediate and small break loss-of-coolant accidents (IBLOCA and SBLOCA). The test result showed that PECCS could effectively depressurize the reactor coolant system by supplying the safety injection water from the safety injection tanks (SITs). The result pointed out that the safety injection from IRWST should have been activated earlier to inhibit the excessive core heat-up. The sequence of the PECCS injection and the major thermal hydraulic transient during the SBLOCA transient was similar to the result of the IBLOCA test with the equivalent PECCS condition. The test data can be used to evaluate the capability of thermal hydraulic safety analysis codes in predicting IBLOCA and SBLOCA transients under an operation of passive safety system.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1253-1260
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• 2022

This paper reports the control method for the core power of the China initiative Accelerator Driven System (CiADS) facility. In the CiADS facility, an intense external neutron source provided by a proton accelerator coupled to a spallation target is used to drive a sub-critical reactor. Without any control rod inside the sub-critical reactor, the core power is controlled by adjusting the proton beam intensity. In order to continuously change the beam intensity, an adjustable aperture is considered to be used at the Low Energy Beam Transport (LEBT) line of the accelerator. The aperture size is adjusted based on the Proportional Integral Derivative (PID) controllers, by comparing either the setting beam intensity or the setting core power with the measured value. To evaluate the proposed control method, a CiADS core model is built based on the point reactor kinetics model with six delayed neutron groups. The simulations based on the CiADS core model have indicated that the core power can be controlled stably by adjusting the aperture size. The response time in the adjustment of the core power depends mainly on the adjustment time of the beam intensity.

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1537-1546
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• 2017

Many thermal-hydraulic tests have been conducted at the Korea Atomic Energy Research Institute for verification of the SMART (System-integrated Modular Advanced ReacTor) design, the standard design approval of which was issued by the Korean regulatory body. In this paper, the contributions of these tests to the standard design approval of SMART are discussed. First, an integral effect test facility named VISTA-ITL (Experimental Verification by Integral Simulation of Transients and Accidents-Integral Test Loop) has been utilized to assess the TASS/SMR-S (Transient and Set-point Simulation/Small and Medium) safety analysis code and confirm its conservatism, to support standard design approval, and to construct a database for the SMART design optimization. In addition, many separate effect tests have been performed. The reactor internal flow test has been conducted using the SCOP (SMART COre flow distribution and Pressure drop test) facility to evaluate the reactor internal flow and pressure distributions. An ECC (Emergency Core Coolant) performance test has been carried out using the SWAT (SMART ECC Water Asymmetric Two-phase choking test) facility to evaluate the safety injection performance and to validate the thermal-hydraulic model used in the safety analysis code. The Freon CHF (Critical Heat Flux) test has been performed using the FTHEL (Freon Thermal Hydraulic Experimental Loop) facility to construct a database from the $5{\times}5$ rod bundle Freon CHF tests and to evaluate the DNBR (Departure from Nucleate Boiling Ratio) model in the safety analysis and core design codes. These test results were used for standard design approval of SMART to verify its design bases, design tools, and analysis methodology.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.735-744
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• 2012

In order to quantify the flow distribution characteristics of APR+ reactor, a test was performed on a test facility, ACOP ($\underline{A}$PR+ $\underline{C}$ore Flow & $\underline{P}$ressure Test Facility), having a length scale of 1/5 referring to the prototype plant. The major parameters are core inlet flow and outlet pressure distribution and sectional pressure drops along the major flow path inside reactor vessel. To preserve the flow characteristics of prototype plant, the test facility was designed based on a preservation of major flow path geometry. An Euler number is considered as primary dimensionless parameter, which is conserved with a 1/40.9 of Reynolds number scaling ratio. ACOP simplifies each fuel assembly into a hydraulic simulator having the same axial flow resistance and lateral cross flow characteristics. In order to supply boundary condition to estimate thermal margins of the reactor, the distribution of inlet core flow and core exit pressure were measured in each of 257 fuel assembly simulators. In total, 584 points of static pressure and differential pressures were measured with a limited number of differential pressure transmitters by developing a sequential operation system of valves. In the current study, reactor flow characteristics under the balanced four-cold leg flow conditions at each of the cold legs were quantified, which is a part of the test matrix composing the APR+ flow distribution test program. The final identification of the reactor flow distribution was obtained by ensemble averaging 15 independent test data. The details of the design of the test facility, experiment, and data analysis are included in the current paper.

• 한국추진공학회지
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• 제17권4호
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• pp.63-72
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• 2013

탄화수소 스크램제트 엔진 시험을 위하여 한국항공우주연구원 스크램제트 엔진 시험설비의 마하 5 노즐과 디퓨저가 제작되었다. 설비 시동을 개선을 위해 디퓨저 가이드를 장착하였으나 폐색율 60% 엔진 모델을 장착한 상태에서 설비의 과대 팽창으로 인한 엔진 불시동을 확인, 이를 개선하기 위하여 모델 위치를 전방으로 이동하여 설비와 엔진의 시동을 확인하였다. 코어 유동을 측정을 위하여 피토레이크(폐색율 2.3%) 성능시험을 수행하였으며, 설비 노즐의 과소팽창으로 인하여 코어 유동이 디퓨저 쪽으로 갈수록 커지고 있음을 확인하였다. 이는 폐색율이 시험부 유동 양상을 결정짓고 있음을 뜻한다. 폐색율 33% 모델을 장착한 상태에서 설비와 엔진은 원활히 작동하였다. 일련의 시험을 통하여 마하 5 노즐을 장착한 스크램제트 엔진 시험설비는 모델의 폐색율과 관계없이 수직 충격파 효율 약 58%로 시동함을 확인하였다.

• Nuclear Engineering and Technology
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• 제41권10호
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• pp.1263-1274
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• 2009

Several experimental tests to simulate a reflood phase of a cold-leg LBLOCA of the APR1400 have been performed using the ATLAS facility. This paper describes the related experimental results with respect to the thermal-hydraulic behavior in the core and the system-core interactions during the reflood phase of the cold-leg LBLOCA conditions. The present descriptions will be focused on the LB-CL-09, LB-CL-11, LB-CL-14, and LB-CL-15 tests performed using the ATLAS. The LB-CL-09 is an integral effect test with conservative boundary condition; the LB-CL-11 and -14 are integral effect tests with realistic boundary conditions, and the LB-CL-15 is a separated effect test. The objectives of these tests are to investigate the thermal-hydraulic behavior during an entire reflood phase and to provide reliable experimental data for validating the LBLOCA analysis methodology for the APR1400. The initial and boundary conditions were obtained by applying scaling ratios to the MARS simulation results for the LBLOCA scenario of the APR1400. The ECC water flow rate from the safety injection tanks and the decay heat were simulated from the start of the reflood phase. The simulated core power was controlled to be 1.2 times that of the ANS-73 decay heat curve for LB-CL-09 and 1.02 times that of the ANS-79 decay curve for LB-CL-11, -14, and -15. The simulated ECC water flow rate from the high pressure safety injection pump was 0.32 kg/s. The present experimental data showed that the cladding temperature behavior is closely related to the collapsed water level in the core and the downcomer.

• 한국유체기계학회 논문집
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• 제18권5호
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• pp.42-48
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• 2015

To improve the core technology of the micro gas turbine, the performance test facility was developed. This paper is focusing on the explanation of the characteristics of micro gas turbine and its assist devices. Major part of micro gas turbine were radial type of compressor, annular type of combustor, radial type of turbine, thrust foil bearing, radial foil bearing and generator. The assist devices were consist of exhaust duct, inverter, data acquisition system, load bank and test cell. Before building up the test facility, the component test was previously conducted to confirm the component performance. After the test facility was prepared, the motoring test was conducted to investigate the rotor dynamic characteristics of the micro gas turbine. Also, the part load performance test was performed. With a developed micro gas turbine test facility, the improved core technology about the micro gas turbine can be suggested to the related industries.

• 한국환경복원기술학회지
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• 제18권6호
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• pp.111-133
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• 2015

This study was carried out to survey the vascular plants of Baekdudaegan Arboretum area. The results are as follows. The numbers of flora in this study area were summarized as 655 taxa including 95 families, 332 genera, 567 species, 5 subspecies, 72 varieties and 11 formas. The rare plants were 17 taxa including Parasenecio firmus, Rhododendron micranthum, Iris odaesanensis, Lysimachia coreana and so forth. The Korean endemic plants were 16 taxa including Weigela subsessilis, Heloniopsis koreana, Salix koriyanagi, Vicia chosenensis and so forth. Plants Adaptable to Climate Change were Northern plants 18 species, Southern plants 2 species, endemic plants 10 species. The naturalized plants were 44 taxa and ratios of naturalized index and urbanization index were estimated Core area 10.2% and 4.9%, Mt. Munsu 4.9% and 2.3% and Mt. Okseok 5.5% and 2.6%. The floristic regional indicator plants found in this area were 3taxa(2.5%) of grade V, 12taxa(11.0%) of grade IV, 22taxa(20.2%) of grade III, 35taxa(32.1%) of grade II. In life forms, hemicryptophytes were The most dominant. Next was a Therophytes. In addition, 492 taxa were categorized by usage into 8 groups, as follows: Edible 239taxa(36.5%), Fiber 10taxa(1.5%), Industrial 1taxon(0.2%), Miscellaneous 183taxa(27.9%), Ornamental 65taxa(9.9%), Pasturing 259taxa(39.5%), Siscellaneousg 14taxa(2.1%) and Timer 21taxa(3.2%).

• 한국농촌건축학회논문집
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• 제10권3호
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• pp.67-74
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• 2008

The roles and needs for the greentourism facilities require the associated functions and systems which can be determined from considering the existing successful facilities. Some of successful examples for the greentourism facilities in Japan have been investigated, and their functions and systems carefully examined. This paper is intended to provide a meaningful step for introducing and applying the functions and systems for the greentourism facilities in Japan to Korea. The facilities should support the greentourism that leads to the active cultural exchange between urban and rural areas. The required specific facilities are discussed in this paper. For newly developed facilities, restaurants, specialty stores, and hotels may be effective facilities for the greentourism. The design for the entire greentourism facilities should consider, for the development of the area, the several kinds of required functions of the greentourism, such as the travel guide center, the marketing center, the information center, the business center, the human resources center, and the environment conservation center.