• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1999년도 추계 학술발표회 논문집
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• pp.149-154
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• 1999

This paper describes a passive safety injection system with free piston Stirling pump working withabundant decay heat in the nuclear reactor during the hypothetical accident. The water column in the tube assembly connected from the hot chamber to the cold chamber in the pump oscillates periodically due to thermal volume changes of non-condensable gas in each chamber. The oscillating pressure in the water column is converted into the pumping power with a suction-and-bleed type valve assembly. In this paper a dynamic model describing the frequency of oscillation and pumping pressure is developed. It was found that the pumping pressure is a function of the temperature difference between the chambers. Also, the frequency oscillation depends on the length of the tube with water column.

• Nuclear Engineering and Technology
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• 제44권6호
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• pp.561-586
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• 2012

This paper describes a summary of final prediction results by system-scale safety analysis codes during the OECD/NEA/CSNI ISP-50 exercise, targeting a 50% Direct Vessel Injection (DVI) line break integral effect test performed with the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS). This ISP-50 exercise has been performed in two consecutive phases: "blind" and "open" phases. Quantitative comparisons were performed using the Fast Fourier Transform Based Method (FFTBM) to compare the overall accuracy of the collected calculations. Great user effects resulting from the combination of the possible reasons were found in the blind phase, confirming that user effect is still one of the major issues in connection with the system thermal-hydraulic code application. Open calculations showed better prediction accuracy than the blind calculations in terms of average amplitude (AA) value. A total of nineteen organizations from eleven countries participated in this ISP-50 program and eight leading thermal-hydraulic system analysis codes were used: APROS, ATHLET, CATHARE, KORSAR, MARS-KS, RELAP5/MOD3.3, TECH-M-97, and TRACE.

• Journal of Acupuncture Research
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• 제22권5호
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• pp.49-55
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• 2005

Objectives : In order to ensure safe Herbal Acupuncture treatment, the quality of needle tip is much important. Therefore we investigated micromorphological characteristics of Herbal Acupuncture needle tip according to the number of injection. Methods : We have selected the 26 Gage syringes & 29 Gage syringes that using currently in Herbal Acupuncture treatment. And we evaluated the change of shape of Herbal Acupuncture needle tip after several times of injection by Inverted System Microscope(x 200). Results & Conclusion : We found at Herbal Acupuncture needle tips had several defects such as hooked, scuffed, lump and irregular, stubbed or malformed shape in spite of new syringes. And we found at Herbal Acupuncture needle tips had several defects that is harmful to body such as mild pain, possibility of damage of tissue after several times of injection. Therefore it is necessary to pay attention to use Herbal Acupuncture needle tips.

• 한국유체기계학회 논문집
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• 제4권3호
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• pp.53-61
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• 2001

Vortex type Fluidic Device(FD) which is installed at the bottom of Safety Injection Tank(SIT) controls the discharge flow rate from the tank. In case of loss of coolant accident the injection water flows into primary system in two steps; initial high flow rate for certain period of time and subsequent low flow rate. By two-step control of the discharge flow rate, FD can ensure the effective use of water in the tank. A small-scale FD has been tested to obtain a required flow characteristics maintaining full pressure and height of prototype, which are the major contributing parameters. Through the testing of many different arrangements of internal geometry of FD, most appropriate one was selected and its performance data was obtained. As characteristics of FD, time dependent Euler number, flow rate and pressure are presented and discussed. Also a method to predict the full size FD is presented.

• 한국항행학회논문지
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• 제27권4호
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• pp.436-446
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• 2023

안전 필수 분야의 전장 장비에서 다양한 고장요인 (고장모드)에 따른 고장 영향 분석 (FMEA, Failure Mode and Effects Analysis)이 필수적이다. 이는 기기나 시스템의 잠재적인 결함들을 식별하고, 그로 인한 발생 가능한 위험을 평가하여 이를 방지하거나 관리하기 위한 개선안을 수립한다. 그러나 최근 시스템의 복잡성이 증가하고 소프트웨어의 영향이 중요해지며 전통적인 FMEA 만을 설계 단계에 적용하는 것이 어려운 상황이다. 본 논문은 모델기반설계기법을 기반으로한 Automatic FMEA 방식을 제안한다. 모델의 구조와 동작을 자동으로 분석하여 FMEA를 수행할 수 있게 하여, 설계 초기 단계에서도 고장모드 분석이 가능하게 한다. 사례연구로 차량 연료 제어 시스템을 대상으로 Automatic FMEA를 수행하였다. 본 연구는 Automatic FMEA 분석도구의 성능을 입증하는 동시에, 향후 연구 방향을 제안한다.

• Nuclear Engineering and Technology
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• 제41권9호
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• pp.1157-1170
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• 2009

A variety of Generation III/III+ reactor designs featuring enhanced safety and improved economics are being proposed by nuclear power industries around the world to solve the future energy supply shortfall. Nanofluid coolants showing an improved thermal performance are being considered as a new key technology to secure nuclear safety and economics. However, it should be noted that there is a lack of comprehensible design works to apply nanofluids to Generation III+ reactor designs. In this work, the review of accident scenarios that consider expected nanofluid mechanisms is carried out to seek detailed application spots. The Axiomatic Design (AD) theory is then applied to systemize the design of nanofluid-engineered nuclear safety systems such as Emergency Core Cooling System (ECCS) and External Reactor Vessel Cooling System (ERVCS). The various couplings between Gen-III/III+ nuclear safety features and nanofluids are investigated and they try to be reduced from the perspective of the AD in terms of prevention/mitigation of severe accidents. This study contributes to the establishment of a standard communication protocol in the design of nanofluid-engineered nuclear safety systems.

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1890-1901
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• 2022

We have assessed the applicability of the thermal-hydraulic system analysis code, SPACE, to a small modular reactor called SMART. For the assessment, the experimental data from a scale-down integral-test facility, SMART-ITL, were used. It was conformed that the SPACE code unrealistically calculates the safety injection flow rate through the CMT and SIT during a small-break loss-of-coolant experiment. This unrealistic behavior was due to the overprediction of interfacial heat transfer at the steam-water interface in a vertically stratified flow in the tanks. In this study, a special thermal-hydraulic component model has been developed to realistically calculate the interfacial heat transfer when a strong non-equilibrium two-phase flow is formed in the CMT or SIT. Additionally, we developed a special heat structure model, which analytically calculates the heat transfer from the hot steam to the cold tank wall. The combination of two models for the tank are called the special component model. We assessed it using the SMART-ITL passive safety injection system (PSIS) test data. The results showed that the special component model well predicts the transient behaviors of the CMT and SIT.

• Safety and Health at Work
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• 제2권3호
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• pp.290-300
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• 2011

Objectives: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods: Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results: In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion: When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.163-170
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• 2000

Accident statistics shows that the portion of fatal occupant injuries due to side impacts is considerably high. The side impact usually leads to a severe intrusion of side structure into the passenger compartment. Furthermore, the safety zone for the side impact is relatively small compared to the front impact. Those kinds of physics for side impact frequently result in a fatal injury for the occupant. Therefore, NHTSA and EEVC are trying to intensify the regulation for the occupant protection against side impact. Both the regulation and recent market trends are asking for an installation of side airbag. There are several types of system configuration for side impact sensing. In this paper, we adopt the acceleration-based remote sensing method for the side airbag control system. We mainly focus on the development of hardware and crash discrimination algorithm of remote sensing unit. The crash discrimination algorithm needs fast decision of airbag firing especially for high-speed side impact such as FMVSS 214 and EEVC tests. It is also required to distinguish between low-speed fire and no-fire events. The algorithm should have a sufficient safety margin against any misuse situation such as hammer blow, door slam, etc. This paper introduces several firing criteria such as acceleration. velocity and energy criteria that use physical value proportional to crash severity. We have made a simulation program by using Matlab/Simulink to implement the proposed algorithm. We have conducted an algorithm calibration by using real crash data for 2,500cc vehicle. The crash performance obtained by the simulation was verified through a pulse injection method. It turned out that the results satisfied the system requirements well.

• 지질공학
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• 제30권3호
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• pp.269-278
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• 2020

본 연구에서는 현장 주입 시험 및 3차원 수치모델을 이용하여 상류 소분지에서의 수직정을 이용한 지하수 인공함양 효과를 예비 평가하였다. 현장 주입 시험의 주입량, 지하수위 및 입도 분석 자료에 의한 수리전도도 등을 이용하여 모델의 공당 주입량을 20, 37.5, 60, 75 ㎥/day로 설정하였으며, 주입 간격에 따른 총 28개의 경우에 대하여 MODFLOW를 활용한 수치모델을 실시하여 지하수위 및 물수지 변화를 분석하였다. 주입 후 주변 관측정에서의 지하수위 상승이 공당 주입량과 비례적인 선형 관계를 보이진 않았으며, 주입 간격이 길어지면 누적 효과가 감소하여 최대 수위상승 시기가 짧아지는 것으로 나타났다. 또한 4가지 경우의 공당 주입량을 매일 연속으로 주입하여 총량 1,200 ㎥을 주입할 경우, 주입량 대비 36.5~65.3%의 함양 효과가 나타나는 것으로 분석되었다. 그러나 장기간의 가뭄에 대응하고 보다 지속적인 양수를 위해서는 차수벽 등 지하수 저류시설을 병행한다면 보다 효과적일 것으로 보이며, 추후 주입 시설의 최적화 및 함양-취수의 시나리오 확보를 통하여 안정적인 인공함양 시스템 구축이 가능할 것이다.