• 한국안전학회지
• /
• 제25권3호
• /
• pp.118-122
• /
• 2010

원자력발전소의 운전 유연성 증대, 안전성 및 경제성 향상, 정비 부담을 완화하기 위해 비상디젤발전기의 허용정지시간 연장이 요구된다. 확률론적안전성평가(probabilistic safety assessment) 기법으로 현재의 비상디젤발전기의 허용정지 시간을 3일에서 7일, 10일, 14일로 연장시 안전성 영향을 평가하였다. 종합적으로 평가결과, 비상디젤발전기의 허용정지시간 연장시 EDG 점검 또는 정비기간 중 인적실수으로 인한 발전소 불시정지 예방 및 안전성을 향상 시키는 것으로 분석되었다.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1999년도 춘계학술발표회요약집
• /
• pp.195-195
• /
• 1999

• Journal of Communications and Networks
• /
• 제16권2호
• /
• pp.110-120
• /
• 2014

This article proposes a spectrum sharing method which can avoid the mutual interference in both primary and secondary systems. The two systems make them a priority to use two single-dimension orthogonal signals, the real and imaginary pulse amplitude modulation signals, if the primary system is not in outage with this use. A secondary transmitter is selected to be the primary relay and the active secondary source to perform this. This allows a simultaneous spectrum access without any mutual interference. Otherwise, the primary system attempts to use a full two-dimensional signal, the quadrature amplitude modulation signal. If there is no outage with respect to this use, the secondary spectrum access is not allowed. When both of the previous attempts fail, the secondary system is allowed to freely use the spectrum two whole time slots. The analysis and simulation are provided to analyze the outage performance and they validate the considerable improvement of the proposed method as compared to the conventional one.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1998년도 추계학술발표회요약집
• /
• pp.172-172
• /
• 1998

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권9호
• /
• pp.4446-4462
• /
• 2019

In this paper, we focus on interference cancellation for three-hop cognitive radio networks (CRNs) over Rayleigh fading channels. In CRNs, secondary users (SUs) are allowed to opportunistically utilize the licensed spectrum during the idle time of primary users (PUs) to achieve spectrum sharing. However, the SUs maybe power constrained to avoid interference and cover a very short transmission range. We here propose an interference cancellation scheme (ICS) for three-hop CRNs to prolong the transmission range of SUs and improve their transmission efficiency. In the proposed scheme, a flexible transmission protocol is adopted to cancel the interference at both secondary relays and destinations at the same time. And a closed-form expression for the secondary outage probability over Rayleigh fading channels is derived to measure the system performance. Simulation results show that the proposed scheme can significantly reduce the secondary outage probability and increase the secondary diversity in comparison with the traditional cases.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1995년도 추계학술발표회논문집(2)
• /
• pp.568-573
• /
• 1995

Technical Specifications (TSs) for a nuclear power plant is an important licensing document which defines various operational requirements or conditions. Recently, many researchers have evaluated the risk impacts associated with the TS requirements, using probabilistic safety assessments becoming widely available. This paper presents insights gained km our review of recent risk-based analyses of TSs, focussing on surveillance requirements and AOT (allowed outage time) requirements.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 2005년도 추계학술발표회
• /
• pp.546-547
• /
• 2005

• 한국안전학회지
• /
• 제15권4호
• /
• pp.150-156
• /
• 2000

In this paper, the human error contributions to the system unavailability are calculated and compared to the mechanical failure contributions. The system unavailability is a probability that a system is in the failed state at time t, given that it was the normal state at time zero. It is a function of human errors committed during maintenance and tests, component failure rates, surveillance test intervals, and allowed outage time. The THERP (Technique for Human Error Rate Prediction), generally called "HRA handbook", is used here for evaluating human error rates. This method treats the operator as one of the system components, and human reliability is assessed in the same manner as that of components. Based on the calculation results, the human error contribution to the system unavailability is shown to be more important than the mechanical failure contribution in the example system. It is also demonstrated that this method is very flexible in that it can be applied to any hazardous facilities, such as gas valve stations and chemical process plants.ss plants.