• 디지털산업정보학회논문지
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• 제18권2호
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• pp.39-48
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• 2022

The application of digital technology to instrumentation and control systems in nuclear power plants has overcome many shortcomings of analog technology, but the threat of cybersecurity has increased. Along with other systems, the reactor protection system also uses digital-based equipment, so responding to cybersecurity threats is essential. We generally determine cybersecurity threats according to the role and function of the system. However, since the instrumentation and control system has various systems linked to each other, it is essential to analyze cybersecurity threats together between the connected systems. In this paper, we analyze the cybersecurity threat of the reactor protection system with the associated facilities. To this end, we quantitatively identified the risk of the reactor protection system by considering safety functions, a communication type, the use of analog or digital-based equipment of the associated systems, and the software vulnerability of the configuration module of the reactor protection system.

• 방송공학회논문지
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• 제10권2호
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• pp.131-138
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• 2005

High-quality digital broadcasting contents are susceptible to illegal copy and unauthorized redistribution, which makes broadcasters difficult to protect valuable media assets. So, broadcasters and content providers need the technology for copyright protection of professional digital content. Digital watermarking technology is one of the most actively developed solutions for the copyright protection. This paper suggests the requirements of watermarking technology in DTV(Digital TV) environment for copyright protection and shows the developed real-time watermark embedding/detecting system for HD(High Definition)/SD(Standard Definition) video and experimental results of the system against watermark attack tests. Our watermarking system meets the watermarking requirements of invisibility, robustness and security of DTV environment.

• Nuclear Engineering and Technology
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• 제22권1호
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• pp.45-57
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• 1990

아날로그와 디지탈 보호계통의 정상상태 여유도를 비교하였다. 비교된 예는 웨스팅하우스사의 OP Delta T 및 OT Delta T 계통과 CE사의 CPCS 계통이다. 안전해석 방법의 차이에 의한 여유도 영향을 제거하기 위해 Dynamic Offset은 고려하지 않았다. 핵연료봉 중심선의 용융을 방지하는데 있어서 디지탈 보호계통이 아날로그 보호계통보다 약 30% 출력 정도의 운전 여유도를 더 가졌다. DNB를 방지하는데 있어서는 주기말에서는 양 보호계통이 비슷한 여유를 가졌으나 주기초에서는 디지탈 보호계통이 약 10%의 더 많은 운전여유를 가지는 것으로 판단된다.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.105-112
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• 2006

The main function of a reactor protection system is to maintain the reactor core integrity and the reactor coolant system pressure boundary. Generally, the reactor protection system adopts the 2-out-of-m redundant architecture to assure a reliable operation. This paper describes the safety assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures such as the random hardware failures, common cause failures, operator errors, and the fault tolerance mechanisms implemented in the reactor protection system. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system, and applied to the reactor protection system being developed in Korea to identify design weak points from a safety point of view.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.84-86
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• 2005

The digital systems such as PLC or DCS have been applied to non-safety systems of nuclear power plants because of many difficulties in using analog systems. Nowadays, digital systems have been applied to safety systems of the plants such as reactor protection system. One of the main advantages of digital systems is applicability of automatic testing methods to the systems. The protection system requires high-reliability and high-availability because it shall minimize the propagation of abnormal or accident conditions of nuclear power plants. The calculation of reliability and availability of systems depends on the maintenance period of the system. In general, the maintenance period of the protection system is one-month in case of the manual test. However, the cycle of test can be shortened in several hours by using automatic periodic testing. The reliability and availability of the system is better when test period is shortened because the reliability and availability is inverse proportion to the test period. In this research, we developed the automatic periodic testing method for KNICS Reactor Protection System, which can test the system automatically without an operator or a tester. The automatic testing contained all functions of reaction protection systems from analog-to-digital conversion function of the bistable Processor to the coincident trip function of the coincident processor. By applying the automatic periodic testing to reaction system, the maintenance cost can be cut down and the reliability can be increased.

• 산업공학
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• 제23권1호
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• pp.68-77
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• 2010

Digital reactor protection system which consists of many identical modules, is fault- tolerant to provide high safety. The modules themselves including DSP(digital signal processing) card are also fault-tolerant in nature. This paper assesses the safety for being-designed digital reactor protection system of 2-out-of-4 G structure with lockout. Some interesting design alternatives are compared. Fault tree analysis for assessing system safety is performed by Relex software. The selected reactor protection system fully satisfies EPRIURD stipulation of mean failure time of 50 years.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.103.2-103
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• 2001

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.81-83
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• 2005

The Reactor Protection System (RPS) is a very important system in a nuclear power plant because the system shuts down the reactor to maintain the reactor core integrity and the reactor coolant system pressure boundary if the plant conditions approach the specified safety limits. This paper describes the unavailability assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system. and applied to the reactor protection system being developed in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1496-1499
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• 1997

Recently the major requirements have emerged in industrial substation system field. One is the simple arrangement of main power supply equipment and the other is the introduction of highly computer-controlled system for operation, maintenance and protection. This paper deals with the systems including motor-type relay systems, supervisory and control systems, digital type relay protectiion systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.51-54
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• 1992

Protection and control systems play a prominent part in avoiding power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements on modern power system, protection speed, selectivity, sensitivity, dependability, and security are essential to ensure reliability. These functions on be satisfied by taking advantage of microprocessor and communication technologies, and digital protection relays (systems) have been developed and applied to real power system enhancing reliability and saving money. It is necessary to have a tool to analyze the functions and algorithms of digital relays for installing them to power system. The purpose of this study is to develop a digital relay simulation program to estimate digital relay performances during system faults. Components of digital protective relay including analog filter, sampling unit, digital filter, and relay logic are modeled in this program.