• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.56.4-56
• /
• 2001

Using GPS in the navigation systems such as aviation, maritime and land applications, integrity is considered importantly with accuracy for safety. Integrity monitoring performed in the GPS receiver itself is Receiver Autonomous Integrity Monitoring (RAIM) and need not an independent ground monitoring station. RAIM algorithm uses redundant information when more than four satellites are visible and makes consistency checks between measurement information to alarm users whether the system is operating out of its specified performance limits. Selective Availability (SA) that was used to protect the security interests of the U.S. and its allies by globally denying the full accuracy of the civil system was turned off on May 1, 2000 ...

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집A
• /
• pp.459-464
• /
• 2001

For major nuclear power plant components periodic inspections and integrity assessments are needed for the safety. But many flaws are undetectable due to sampling inspection. Probabilistic integrity assessment is applied to take into consideration of uncertainty and variance of input parameters arise due to material properties, applied load and undetectable flaws. This paper describes a Probabilistic Fracture Mechanics(PFM) analysis based on Monte Carlo(MC) algorithms. Taking important parameters as probabilistic variables such as fracture toughness, crack growth rate and flaw shape, failure probability of major nuclear power plant components is archived as a results of MC simulation. For the verification of these analysis, a comparison study of the PFM analysis using other commercial code, mathematical method is carried out and a good agreement was observed between those results.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 B
• /
• pp.813-815
• /
• 1998

Engineered Safety Features-Component Control Systems(ESF-CCS) are those I&C systems that control safety equipment used to maintain the integrity of reactor coolant pressure boundary. This paper illustrates distinctive features and improved design concepts of Korea Next Generation Reactor(KNGR) based on the experience obtained through prototyping of ESF-CCS.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 B
• /
• pp.1303-1305
• /
• 2003

It is very important to ensure system safety during the process of developing a system. Railway system is also devoting a great portion for the safety. Nowadays many countries leading railway industry have their own system assessment principles according to the situation of their train control systems. In this paper, several principles to derive Safety Integrity Level (SIL) are represented in the railway signalling system. The characteristics of those principles are also considered respectively.

• 한국가스학회지
• /
• 제6권1호
• /
• pp.66-73
• /
• 2002

본 연구에서는 결함수목 분석법을 이용하여 Safety Integrity Level(SIL)을 평가하고 시스템의 목표한 SIL에 도달하지 못할 경우에 신뢰도 분석과 시스템 retrofit을 통해서 목표한 SIL을 만족시키게 하는 방법을 개발하였다. 신뢰도 분석에 근거한 SIL 평가 방법을 검증하기 위해서 415V Diesel BUS에 대해서 위험성 분석을 수행하였다. 기존의 415V Diesel BUS에 대한 이용가능 상태는 $99.40\%$로 SIL 2등급에 해당된다. 개발된 평가방법을 이용하여 diesel generator와 isolator switch의 교체후 시스템의 이용가능 상태는 $99.94\%$ SIL 3등급으로 상승되었다. 본 연구에서 제시한 신뢰도에 근거한 SIL 평가 방법을 적용하면 사고 예방과 손실감소로 일어나는 유지보수 비용의 절감 등을 가져오면 물론 시스템의 신뢰도를 극대화 할 수 있다.

• 한국산업융합학회 논문집
• /
• 제27권3호
• /
• pp.609-618
• /
• 2024

System reliability prediction in the development stage is increasingly crucial to reliability growth management to satisfy its target reliability, since modern system usually takes a form of complex composition and various complicated functions. In most cases of development stage, however, the information available for system reliability prediction is very limited, making it difficult to predict system reliability more precisely as in the production and operating stages. In this study, a system reliability prediction process is considered when the reliability-related information such as SIL (Safety Integrity Level) and MTTFd (Mean Time to Dangerous Failure) is available in the development stage. It is suggested that when the SIL or MTTFd of a system component is known and the field operational data of similar system is given, the reliability prediction could be performed using the scaling factor for the SIL or MTTFd value of the component based on the similar system's field operational data analysis. Predicting a system reliability is then adjusted with the conversion factor reflecting the temperature condition of the environment in which the system actually operates. Finally, the case of applying the proposed system reliability prediction process to a high performance mooring platform is dealt with.

• 대한조선학회논문집
• /
• 제49권3호
• /
• pp.239-246
• /
• 2012

It is the well-known fact that most part of goods transported are moved on the unfavorable ocean and even a small amount of accident on sea is extremely dangerous for human lives, financial losses, and social responsibility. Among the several causes of accidents, those by fire have occurred frequently and their damage has been highly serious. The aim of this paper is to assess the risk of fires due to oil leakage in the machinery space. To define the possible fire scenario, our team has performed the search of casualty database and reviewed the previous and various studies in the field. As a result, it is noted that the quantitative risk of the fire scenario have been evaluated on the ground of the FSA risk model. The expected frequency of a fire amounts to incidents during the life of a ship, and the expected financial damage amounts to 5,654 USD per a ship. By adopting Safety Instrumented System (SIS) introduced in IEC 61508 and IEC 61511, SIS model is designed to prevent oil leakage fire as a risk reduction method. It is concluded that System Integrity Level (SIL) 1 seems to be appropriate level of SIS.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제8권3호
• /
• pp.262-276
• /
• 2016

Generally, the Safety Integrity Level (SIL) of a subsea Blowout Preventer (BOP) is evaluated by determining the Probability of Failure on Demand (PFD), a low demand mode evaluation indicator. However, some SIL results are above the PFD's effective area despite the subsea BOP's demand rate being within the PFD's effective range. Determining a Hazardous Event Frequency (HEF) that can cover all demand rates could be useful when establishing the effective BOP SIL. This study focused on subsea BOP functions that follow guideline 070 of the Norwegian Oil and Gas. Events that control subsea well kicks are defined. The HEF of each BOP function is analyzed and compared with the PFD by investigating the frequency for each event and the demand rate for the components. In addition, risk control options related to PFD and HEF improvements are compared, and the effectiveness of HEF as a SIL verification for subsea BOP is assessed.

• 한국압력기기공학회 논문집
• /
• 제7권4호
• /
• pp.57-62
• /
• 2011

As NPPs' operating times increase, the integrity of nuclear components is continually degraded due to aging effects of systems, structures and components. In addition, for the case of continued operation beyond design life, additional aging effects occurred during the extended operating period lead to more degradation of the integrity of nuclear components. Therefore, it is very important to mange and evaluate the aging to secure the safety of NPPs. Wolsong unit 1 is approaching to its design life of 30 years in 2012. The license renewal documents for continued operation of Wolsong unit 1 Is under reviewing now. In this paper, regulatory technologies for continued operation of Wolsong unit 1 developed by KINS will be introduced. That technologies include the safety review guidelines, regulatory guides for aging management program and regulatory program for audit calculation.

• 한국안전학회지
• /
• 제22권1호
• /
• pp.13-18
• /
• 2007

Structural integrity assessment of thin-walled pipes and pipe items has become one of the major issues in the nuclear power plant. ASME Section XI Code Case N-597-2 provides a criterion for acceptance of the pipes. But the code case has several limitations for application and sometimes gives too conservative or non-conservative results. So it is necessary to understand fully the technical bases of the code case. In the code case N-597, the allowable local thicknesses of thinned straight pipes are given for three different cases. Because of the different technical base, each case gives different thickness values and sometimes gives contradictory values. In this paper attempts were made in order to propose a unified rule for the allowable local thickness and in order to remove or relax the restrictions on the application of the code case. For this purpose elastic stress analyses were made using the finite element method and the stress results were examined. Based on the obtained bending stress results, a very simple procedure was proposed to obtain the consistent allowable local thickness for the thinned straight pipes.