• Nuclear Engineering and Technology
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• v.44 no.8
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• pp.919-928
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• 2012

The applications of computers and communication system and network technologies in nuclear power plants have expanded recently. This application of digital technologies to the instrumentation and control systems of nuclear power plants brings with it the cyber security concerns similar to other critical infrastructures. Cyber security risk assessments for digital instrumentation and control systems have become more crucial in the development of new systems and in the operation of existing systems. Although the instrumentation and control systems of nuclear power plants are similar to industrial control systems, the former have specifications that differ from the latter in terms of architecture and function, in order to satisfy nuclear safety requirements, which need different methods for the application of cyber security risk assessment. In this paper, the characteristics of nuclear power plant instrumentation and control systems are described, and the considerations needed when conducting cyber security risk assessments in accordance with the lifecycle process of instrumentation and control systems are discussed. For cyber security risk assessments of instrumentation and control systems, the activities and considerations necessary for assessments during the system design phase or component design and equipment supply phase are presented in the following 6 steps: 1) System Identification and Cyber Security Modeling, 2) Asset and Impact Analysis, 3) Threat Analysis, 4) Vulnerability Analysis, 5) Security Control Design, and 6) Penetration test. The results from an application of the method to a digital reactor protection system are described.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.209-210
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• 2008

In the case of unauthorized individuals, systems and entities or process threatening the instrumentation and control systems of nuclear facilities using the intrinsic vulnerabilities of digital based technologies, those systems may lose their own required functions. The loss of required functions of the critical systems of nuclear facilities may seriously affect the safety of nuclear facilities. Consequently, digital instrumentation and control systems, which perform functions important to safety, should be designed and operated to respond to cyber threats capitalizing on the vulnerabilities of digital based technologies. To make it possible, the developers and licensees of nuclear facilities should perform appropriate cyber security program throughout the whole life cycle of digital instrumentation and control systems. Under the goal of securing the safety of nuclear facilities, this paper presents the KINS' regulatory position on cyber security program to remove the cyber threats that exploit the vulnerabilities of digital instrumentation and control systems and to mitigate the effect of such threats. Presented regulatory position includes establishing the cyber security policy and plan, analyzing and classifying the cyber threats and cyber security assessment of digital instrumentation and control systems.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3694-3703
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• 2021

Instrumentation and Control systems (I&C) play a significant role in nuclear power plants (NPP) and other safety critical systems (SCS). We have conducted a rigorous study and discussions with experienced practitioners worldwide the strategy for the development of I&C systems to investigate the several aspects related to their dependability. We discussed with experienced practitioners that work on nuclear domain with the intention of knowing their approach, they use day-to-day for the development of such systems. The aim of this research is to obtain to provide guidance to those building I&C systems of NPP and have implications on state engineering licensure boards, in the determination of legal liability, and in risk assessment for policymakers, corporate governors, and insurance executives.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1192-1205
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• 2016

Field programmable gate array (FPGA)-based systems are thought to be a practical option to replace certain obsolete instrumentation and control systems in nuclear power plants. An FPGA is a type of integrated circuit, which is programmed after being manufactured. FPGAs have some advantages over other electronic technologies, such as analog circuits, microprocessors, and Programmable Logic Controllers (PLCs), for nuclear instrumentation and control, and safety system applications. However, safety-related issues for FPGA-based systems remain to be verified. Owing to this, modeling FPGA-based systems for safety assessment has now become an important point of research. One potential methodology is the dynamic flowgraph methodology (DFM). It has been used for modeling software/hardware interactions in modern control systems. In this paper, FPGA logic was analyzed using DFM. Four aspects of FPGAs are investigated: the "IEEE 1164 standard," registers (D flip-flops), configurable logic blocks, and an FPGA-based signal compensator. The ModelSim simulations confirmed that DFM was able to accurately model those four FPGA properties, proving that DFM has the potential to be used in the modeling of FPGA-based systems. Furthermore, advantages of DFM over traditional reliability analysis methods and FPGA simulators are presented, along with a discussion of potential issues with using DFM for FPGA-based system modeling.

• Journal of the Korean Professional Engineers Association
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• v.43 no.2
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• pp.45-52
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• 2010

At the end of last year, Korean nuclear power plants, APR-1400 and a research reactor have been contracted to build plants at United Arab Emirates and Jordan. Since 1959, a historical background of nuclear technologies in Korea is summarized. The safety requirements for Instrumentation and Control (I&C) systems in Nuclear Power Plants (NPP) are discussed. Specific descriptions on the typical safety classification of I&C systems, the definitions of the electrical class 1E and the countermeasures against common caused failures are provided. And summaries of typical I&C systems such as the protection systems, the control systems, the instrumentations, the monitoring systems and a control room in NPP are introduced. Strict requirements on the development of the digital computer systems in nuclear applications are described.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.25-38
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• 2023

Instrumentation and control systems measure and control various variables of nuclear facilities to operate nuclear power plants safely. A diverse protection system, a representative instrumentation and control system, generates a reactor trip and turbine trip signal by high pressure in a pressurizer and containment to satisfy the design requirements 10CFR50.62. Also, it generates an auxiliary feedwater actuation signal by low water levels in steam generators. Cybersecurity has become more critical as digital technology is gradually applied to solve problems such as performance degradation due to aging of analog equipment, increased maintenance costs, and product discontinuation. This paper analyzed possible cybersecurity threat scenarios in the diverse protection system using attack trees. Based on the analyzed cybersecurity threat scenario, we calculated the probability of attack occurrence and confirmed the cybersecurity risk in connection with the asset value.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.570-581
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• 2018

Recently, a software program has been used in nuclear power plants (NPPs) to digitalize many instrumentation and control systems. To guarantee NPP safety, the reliability of the software used in safetycritical instrumentation and control systems must be quantified and verified with proper test cases and test environment. In this study, a software testing method using a simulation-based software test bed is proposed. The test bed is developed by emulating the microprocessor architecture of the programmable logic controller used in NPP safety-critical applications and capturing its behavior at each machine instruction. The effectiveness of the proposed method is demonstrated via a case study. To represent the possible states of software input and the internal variables that contribute to generating a dedicated safety signal, the software test cases are developed in consideration of the digital characteristics of the target system and the plant dynamics. The method provides a practical way to conduct exhaustive software testing, which can prove the software to be error free and minimize the uncertainty in software reliability quantification. Compared with existing testing methods, it can effectively reduce the software testing effort by emulating the programmable logic controller behavior at the machine level.

• Nuclear Engineering and Technology
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• v.41 no.4
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• pp.447-454
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• 2009

This paper is a technical review of the research and development results of the Korea Nuclear Instrumentation and Control System (KNICS) project and Nu-Tech 2012 program. In these projects man-machine interface system architecture, two digital platforms, and several control and protection systems were developed. One platform is a Programmable Logic Controller (PLC) for a digital safety system and another platform is a Distributed Control System (DCS) for a non-safety control system. With the safety-grade platform PLC, a reactor protection system, an engineered safety feature-component control system, and reactor core protection system were developed. A power control system was developed based on the DCS. A logic alarm cause tracking system was developed as a man-machine interface for APR1400. Also, Integrated Performance Validation Facility (IPVF) was developed for the evaluation of the function and performance of developed I&C systems. The safety-grade platform PLC and the digital safety system obtained approval for the topical report from the Korean regulatory body in February of 2009. A utility and vendor company will determine the suitability of the KNICS and Nu- Tech 2012 products to apply them to the planned nuclear power plants.

• International Journal of Safety
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• v.3 no.1
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• pp.38-46
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• 2004

This paper introduces the software life-cycle V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop a programmable logic controller (PLC) for safety critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of an engineered safety features-component control system (ESF-CCS) in nuclear power plants. As preparative works for the software V&V, various kinds of software plans and V&V task procedures have been developed according to the software life-cycle management. A number of software V&V tools have been adopted or developed to efficiently support the V&V tasks. The V&V techniques employed in this work include a checklist-based review and inspection, a requirement traceability analysis, formal verification, and life-cycle based software testing.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.6
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• pp.681-687
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• 2014

Nuclear industries have faced unfavorable circumstances such as an obsolescence of the instrumentation and control system, and therefore nuclear society is striving to resolve this issue fundamentally. IEC and IAEA judge that FPGA technology is a good replacement for Programmable Logic Controller (PLC) of Nuclear Instrumentation and Control System. FPGAs are currently highlighted as an alternative means for obsolete control systems. Because the main function inside an FPGA is initially developed as software, good software quality can impact the reliability of an FPGA-based controller. Therefore, it is necessary to establish a software development aspect strategy that enhances the reliability of an FPGA-based controller. In terms of software development, HDL-Programmed Device (HPD) Development Life Cycle is applied into FPGA-based Controller. The burn-in test and environmental(temperature) test should be performed in order to apply into nuclear instrumentation and control system. Therefore it is ensured that the developed FPGA-based controller are normally operated for 352 hours and 92 hours in test chamber of Korea Institute of Machinery and Materials (KIMM).