A Novel More Reliable and Extensible Architecture of Instrumentation and Control Systems

2018 ◽  
Author(s):  
Shuqiao Zhou ◽  
Chao Guo ◽  
Duo Li ◽  
Xiaojin Huang
Keyword(s):  
Communication Technology ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Traditional Architecture ◽  
Digital Instrumentation ◽  
Control Units ◽  
Computing Performance ◽  
Almost All ◽  
And Control

Digital instrumentation and control (I&C) systems are widely used in many industrial areas. In the recent years, the digitalization process for nuclear power plants has also been moving on rapidly. Full digital I&C systems are now adopted in almost all new constructed nuclear power plants. The architecture of a digital I&C system plays a pivotal role for the safety, reliability and security of the whole nuclear power plant. Moreover, for the advanced small modular reactors, both the reliability and extensibility of I&C systems are especially required. Therefore, in this paper we propose a new architecture of the digital I&C systems based on the developed computing performance and communication technology. The control units and the data servers in the new proposed architecture are decentralized and working in a mutually redundant and distributed computing/storage way. Thus the architecture is with a flexible extensibility. Moreover, other control units or data servers can take over the functions of a certain number of failed ones. This characteristic benefits the system’s reliability significantly. The reliability of the new architecture is theoretically evaluated and the results demonstrate that it is much higher than that of the traditional architecture of I&C systems.

Effective Software Verification and Validation Approach for Nuclear Power Plant Digital Instrumentation and Control Systems

2010 ◽  
Author(s):  
Steve Yang ◽  
Jun Ding ◽  
Huifang Miao ◽  
Jianxiang Zheng
Keyword(s):  
Life Cycle ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Software Verification ◽  
Verification And Validation ◽  
Common Cause ◽  
Digital Instrumentation ◽  
And Control ◽  
Software Verification And Validation

All 1000 MW nuclear power plants currently in construction or projected to-be-built in China will use the digital instrumentation and control (I&C) systems. Safety and reliability are the ultimate concern for the digital I&C systems. To obtain high confidence in the safety of digital I&C systems, rigorous software verification and validation (V&V) life-cycle methodologies are necessary. The V&V life-cycle process ensures that the requirements of the system and software are correct, complete, and traceable; that the requirements at the end of each life-cycle phase fulfill the requirements imposed by the previous phase; and the final product meets the user-specified requirements. The V&V process is best illustrated via the so-called V-model. This paper describes the V-model in detail by some examples. Through the examples demonstration, it is shown that the process detailed in the V-model is consistent with the IEEE Std 1012-1998, which is endorsed by the US Regulatory Guide 1.168-2004. The examples show that the V-model process detailed in this paper provides an effective V&V approach for digital I&C systems used in nuclear power plants. Additionally, in order to obtain a qualitative mathematical description of the V-model, we study its topological structure in graph theory. This study confirms the rationality of the V-model. Finally, the V&V approach affording protection against common-cause failure from design deficiencies, and manufacturing errors is explored. We conclude that rigorous V&V activities using the V-model are creditable in reducing the risk of common-cause failures.

Research on the Reliability of Digital Instrumentation and Control System of Nuclear Power Plant Based on Dynamic Flowgraph Methodology

2017 ◽  
Author(s):  
Chen Zhuo ◽  
Zhao Bo ◽  
Yang Jian ◽  
Sun Jin-long
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Failure Modes ◽  
Fault Tree ◽  
Protection System ◽  
Digital Instrumentation ◽  
And Control ◽  
Reactor Protection System ◽  
Tree Approach

With the development of information and computer technology, the Digital Instrumentation and Control (I&C) System has been widely used in nuclear power plants, which leads the tendency of NPPS’ construction and rebuilding on digital I&C system. As an approximate approach, conventional fault tree approach has been used quite often in the analysis of nuclear power plants’ Probability Safety Assessment (PSA), which combine with system components’ failure modes in order to modeling the digital system’s failure. However, for the reason that conventional fault tree approach has a great disadvantage on analyzing the reliability of digital I&C system, which may not be able to fully describe the dynamic behavior of digital I&C system with significant hardware/software/human action process interaction, multi-failure modes and logic loops, it cannot carry on effective modeling and evaluation of digital I&C system. Therefore it is necessary to establish some dynamic approaches to modeling digital I&C system. As a new probability safety analysis method, Dynamic Flowgraph Methodology (DFM) can model the relationship between time sequence and system variables because of its dynamic property. Therefore, DFM can be used to analyze the impact of software failure, hardware failure and external environment, which are closely related to the reliability of the whole system. In the first place, this paper introduces the theoretical basis, model elements and the modeling procedures of DFM and demonstrates how Dynamic Flowgraph Methodology (DFM) can be applied to Reactor Protection System with interactions between hardware/software and physical properties of a controlled process. Meanwhile, in this case, DFM and fault tree methodologies are both used to conduct the PSA for the same top event by calculating the probability of it and finding out the prime implicants of DFM and minimal cutsets of conventional fault tree. During the process of analysis, we mainly evaluate the reliability of reactor trip function of Reactor Protection System (RPS) by using DFM and conventional fault tree approach and mainly focus on modeling the four-way-redundant voting logic and the reactor trip breaker logic. Finally, through the comparison of this two methods and model results, it is concluded that there is a distinct advantage of DFM over conventional fault tree approach by using multi-logic to fully display the fault mode and utilizing decision table to describe the interaction between software and hardware. In general, conclusion can be drawn that, as a dynamic approach, Dynamic Flowgraph Methodology could be more accuracy and effective than conventional fault tree approach in analysis, ensuring the reliability and safety of the whole digital I&C system.

Research and Design of Technology Readiness Levels Evaluating System for Digital Instrumentation and Control System

2013 ◽  
Vol 448-453 ◽  
pp. 3629-3634
Author(s):  
Wen Yuan Yang ◽  
Ning Li ◽  
Ying Ru Zhao
Keyword(s):  
Control System ◽  
Evaluation System ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
New Technologies ◽  
Technology Readiness ◽  
Automatic Data ◽  
Digital Instrumentation ◽  
And Control

Technology Readiness Levels have a great superiority to evaluate new technologies, and have been adopted by U.S. Congress General Accountability Office, Department of Defense and will be considered in numerous other organizations. In this study, Technology Readiness Levels are customized to assess the Digital Instrumentation and Control system of nuclear power plants. The Technology Readiness Levels evaluation system based on Browser/Server structure is designed. The flow chart of the evaluation system, automatic data analysis system, and the tables relation of database are presented. The Browser/Server structure enables multi-experts use Browser to assess the Digital Instrumentation and Control system of nuclear power plants in different places through the Internet. The Technology Readiness Levels evaluation system can easy the organizing work and reduce fees of Technology Readiness assessment works of Digital Instrumentation and Control system.

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