• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.97-103
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• 2011

본 논문에서는 엔진 비상보호시스템 구성 시 주요 고려 사항과 엔진 선행 개발 시험에서의 적용사례를 제시하였다. 액체로켓엔진 선행 개발 시험을 위해 적용된 비상보호시스템은 시험 중 발생한 모든 오작동 상황에서 오류 없이 작동하여 시험을 중지함으로써 추가적인 오작동의 전파를 방지하여 시험시제와 시험설비를 안전하게 보호하는 역할을 성공적으로 수행하였다. 본 연구 결과는 향후 엔진시험을 위한 비상보호시스템 개발 시 유용하게 활용될 것이다.

• 한국안전학회지
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• 제32권1호
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• pp.140-144
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• 2017

Fire protection for nuclear power plants should be designed according to the concept of "Defense in Depth" to achieve the reactor safety shutdown. This concept focuses on fire prevention, fire suppression and safe shutdown. Fire prevention is the first line of "Defense in Depth" and the licensee should establish administrative measures to minimize the potential for fire to occur. Administrative measures should include procedures to control handling and use of combustibles. Electrical cables is the major contributor of fire loads in nuclear power plants, therefore electrical cables should be fire retardant. Electrical cables installed in nuclear power plants should pass the flame test in IEEE-383 standard in accordance with NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants". To assure the fire retardant of electrical cables during design life, both aged and unaged cable specimens should be tested in accordance with IEEE-383. It can be generally thought that the flammability of electrical cables has been increased by wearing as time passed, however the results from fire retardant tests performed in U.S.A and Korea indicate the inconsistent tendency of aging and consequential decrease in flammability. In this study, it is expected that the effective methodology for validation of fire retardant performance would be identified through the review of the results from fire retardant tests.

• 한국유체기계학회 논문집
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• 제17권6호
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• pp.109-114
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• 2014

After the Fukushima accident in 2011, it was revealed that nuclear power plant has the vulnerability to SBO accident and its extension situation without sufficient cooling of reactor core resulting core meltdown and radioactive material release even after reactor shutdown. Many safety systems had been developed like PAFS, hybrid SIT, and relocation of RPV and IRWST as a part of steps for the Fukushima accident, however, their applications have limitation in the situation that supply of feedwater into reactor is impossible due to high pressure inside reactor pressure vessel. The concept of hybrid heat pipe with control rod is introduced for breaking through the limitation. Hybrid heat pipe with control rod is the passive decay heat removal system in core, which has the abilities of reactor shutdown as control rod as well as decay heat removal as heat pipe. For evaluating the cooling performance hybrid heat pipe, a commercial CFD code, ANSYS-CFX was used. First, for validating CFD results, numerical results and experimental results with same geometry and fluid conditions were compared to a tube type heat pipe resulting in a resonable agreement between them. After that, wall temperature and thermal resistances of 2 design concepts of hybrid heat pipe were analyzed about various heat inputs. For unit length, hybrid heat pipe with a tube type of $B_4C$ pellet has a decreasing tendency of thermal resistance, on the other hand, hybrid heat pipe with an annular type $B_4C$ pellet has an increasing tendency as heat input increases.

• 한국정보과학회논문지:소프트웨어및응용
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• 제27권2호
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• pp.120-133
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• 2000

산업현장에서 복합 실시간 계통(HRTS: Hybrid Real-Time Systems) 개발을 위한 정형기법 사용의 주된 장벽은 인지적 어려움이며 이는 또 다른 위험을 초래할 수 있다. 이러한 문제를 극복하기 위해 HRTS 요구분석과 안전성 분석 시 사용자의 인지적 부담을 줄여줄 수 있는 정성적 요구분석 체계를 제안한다. 이 체계는 요구사항 명세를 위한 정성적 정형기법(QFM: Qualitative Formal Method)과 인과정보에 의한 요구사항 안전성 분석기법(CRSA: Causal Requirements Safety Analysis)으로 구성되어 있다. QFM에서는 인공지능 분야에서 연구된 정성추론 이론을 정형명세에 도입하여 요구사항 설계자와 분석자의 인지적 부담을 줄일 수 있도록 하였다. CRSA는 QFM에서 도출한 HRTS 동작의 인과 정보에 따라 체계적으로 위험 원인을 추적할 수 있도록 하여, 기존 결함 트리 분석(FTA: Fault Tree Analysis) 기법의 단점인 분석자의 주관에 의존하는 문제를 해결한다. 월성 원자력 발전소 자동정지계통(Shutdown System 2) 소프트웨어 요구사항 명세와 안전성 분석에 QFM과 CRSA를 적용하여 그 실효성을 입증하고자 하였다.

• Nuclear Engineering and Technology
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• 제39권2호
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• pp.123-128
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• 2007

In order to apply a static fault-tree (FT) method to a system or a plant whose configuration changes dynamically, condition gates and a post processing method are used to effectively accommodate these changes. An operator's performance change, which can be caused by these configuration changes, should also be considered to assess the risk to a plant in a more realistic manner. This study aims to develop an integrated framework to accommodate various configuration changes and their effect on an operator’s performance by using the FT model. We applied a condition-based human reliability assessment (CBHRA) method to consider various conditions endured by an operator. That is, we integrated the CBHRA method with the conventional post processing method for modeling the system configuration changes. The effect of the condition monitoring systems installed in a plant is also considered. In this study, we show an example application of the integrated framework to a probabilistic safety assessment for the shutdown phase of a nuclear power plant.

• Tribology and Lubricants
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• 제14권4호
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• pp.64-71
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• 1998

In this study deals with measurement of the vibration amplitudes of rotor-bearing system supported by foil bearing were performed experimentally, and the stability of the system were analyzed by using those results. Considering initial operating friction, compare bearing lubricated with only air and bearing surface lubricated with oil. Analyzing the transient data, the understanding of the characteristics fur startup and shutdown of rotor-bearing system are available and the dynamic characteristics of the system also can be analyzed exactly.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.773-775
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• 2012

모바일 시스템에 비해 안드로이드 기반 스마트TV 셋톱박스의 경우 직접 전원 연결을 통한 시스템 전원을 공급받기 때문에 갑작스러운 전원차단으로 인한 메모리기반 파일시스템의 손상이 발생하게 된다. 이를 개선하기 위해 init의 중복 실행을 통해 스마트TV OS 프레임워크가 시작되기 전에 해당 파일 시스템의 손상 유무를 판단하여 시스템 체크를 수행하는 방법에 대해 연구한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2182-2184
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• 2002

In this paper we describe a prototype Control Rod Control System(CRCS). The CRCS controls the motion of the full length rod drive mechanisms in response to signals from the Reactor Operator and the Reactor Control System. Each mechanism belongs to either Shutdown Banks or Control Banks. The CRCS also provides information regarding the rod motion, rod position, and the status of the Rod Control System. The prototype CRCS will be used to obtain the requirements for detailed design of a full-scale CRCS.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.683-690
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• 1996

The MIDLOOP code has been developed for the evaluation of RES pressurization transients initiated from a loss-of-Residual Heat Removal System (RHRS) during mid-loop operation after reactor shutdown. It provides a fast running and realistic tool for studying parametrically the response of important plant parameters such as pressure, temperature, and level to various plant combinations of the primary side vent, makeup, and leakage procedures and the steam generator (SG) conditions. The code consists of ten nodes representing the primary and secondary sides of a nuclear power plant and can analyze the effect of air on the primary system pressurization and primary to secondary heat transfer. The analysis results of the MIDLOOP code are in good agreement with the ROSA-IV/LSTF experiment without opening in the RCS.

• Nuclear Engineering and Technology
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• 제28권5호
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• pp.500-505
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• 1996

At the reference plant(Wolsong unit No. 1) a manual poison sampling system is provided to periodically sample gadolinium from each tank and analyze it in the laboratory to provide assurance that adequate poison concentration in each tank is maintained. The AECB required a continuous, on-line monitoring system. On Wolsong unit No. 2, process piping adapter and new instrument loops added to the Liquid Injection Shutdown System(LISS) which is part of SDS2. The new instrument loops continuously monitor SDS2 poison conductivity and initiate an alarm when the poison concentration is too low.