核电安全级DCS系统多节点通信网络容错技术的开发及应用

为保证核电安全级DCS系统中控制站、安显站、网关站等之间双向、大容量数据的可靠通信,本文设计了一种基于光纤通信技术的多节点通信容错技术,并详细介绍了该光纤通信容错技术的设计方案及实现方法。该方案采用光开关切换技术灵活改变光传输路径,支持多节点通信网络容错通信,在多节点通信网络中某一个或多个节点发生故障时,不影响其他节点的正常通信,可灵活配置和管理多节点通信动态光路径切换,实现了核电安全级DCS系统中站与站之间的通信效率,提高了产品的可靠性和可用性,实现了多节点通信网络的容错设计。     

应用于脉冲辐射场测量的分布式无人值守测试系统

介绍了一种用于脉冲辐射场测量的分布式无人值守测试系统的开发。该测试系统采用分布式结构,通过LAN网络和光纤通讯设备进行互联。系统利用基于TCP/IP协议开发的网络程序实现了实验数据传输、备份与显示。采用服务器和工业PC计算机控制实验设备,利用VISA技术开发测试控制程序实现了对多种仪器设备的控制。通过用VNC技术实现了基于LAN的网络计算机状态监控和控制,并利用NTP技术实现了测试系统时钟同步。     

水下冲击波的分布式获取节点技术研究

针对分布式水下爆炸瞬态信号的获取设计了采集与存储系统。整个分布式系统以无线传感器网络为基础,测试节点与主控站之间的数据采用无线方式传输。使用基于SPI总线协议的无线模块,主控站通过发送命令控制节点的数据存储与存储测试,同时各个传感器节点加入时间同步技术,使得各测试节点互不相关且具有记忆重发的功能。     

中频供电微机自动监测系统的研究与实现

提出了一种基于串口通信服务器的新型分布式中频供电自动监测系统的设计方案,并详细地阐明了系统的实现原理方法及关键技术。该系统利用了串口服务器的实时控制转换功能,实现了双机备份冗余数据采集功能。新装置采用网络自诊断技术及光电隔离通讯接口,提高了通讯抗干扰能力,通讯采用报警信息数据优先发送及重复循环发送等技术,克服了原监测系统网络通信速度慢的弊端,增强了供电监测系统报警反映的快速性及可靠性。经现场实际运行表明,新供电监测系统比原系统功能更加完善,使用更加方便,具有更高的可靠性和稳定性,报警更加迅速,而且便于事故后故障分析等优点,同时还具有很强的系统扩展能力及推广价值。     

石油管道泄漏检测与定位系统设计

为了提高传统负压力波检测石油管道泄漏的灵敏度和定位精度,采用C/S架构设计了多点分布式的检测和定位监测系统,该系统由管道沿线检测节点、监测分站和监测中心三部分构成.检测节点采集管道内部的压力信号,并通过GPRS网络传输到监测中心,实现对整个管道压力的实时在线监测.利用多点分布式负压力波检测方法以及相关分析法理论对采集到...     

基现场可编程门阵列的反应堆数字化保护系统设计

介绍了一种基于现场可编程门阵列（Field Programmable Gate Array,即FPGA）的新型反应堆保护系统的设计方案,辅以微处理器作为热备份的冗余,以实现设备的多样性。系统采用三取二的表决方式,FPGA部分执行主要的保护功能,并行数据处理和信号传输提高了系统的响应速度,避免了软件共模故障的发生。微控制的使用增强了系统的通讯能力,优化了人机接口界面,并完成辅助的保障功能。     

HXMT电子学系统可靠性预计中冗余备份方式的研究

提出了硬X射线调制望远镜HXMT电子学系统中的两种冗余备份方案,分块备份和整机冷备份,采用元器件计数法对两种方案进行了可靠性预计,分别对三种失效判据下的可靠性预计结果进行比较分析,确定了分块备份的冗余方式更容易得到更高的可靠性和更长的寿命。     

基于UDP/IP协议分布式测试高速数据传输嵌入系统设计

为了解决分布式测试系统中多节点网络化以及整个系统中数据高速传输的问题,提出了一种基于UDP/IP协议的分布式测试高速数据传输嵌入系统。该系统采用了ALTERA公司的NIOS2嵌入系统和硬件协议栈集成芯片CH395完成了分布式测试系统中高速数据传输。该系统具有扩展性能好、通用性强和稳定性高等优点,适用于大范围复杂环境区域内关键参数测试、高速数据传输的分布式测试。     

辐照灭菌电子直线加速器控制系统

本控制系统硬件采用分布式网络控制,分三级对加速器进行监测和控制。硬件采用PLC和PC,软件采用CXP和C语言等编写。本系统在实现了在电子线路控制系统上实现的各项监控功能的基础上,增加了很多新功能,更因为部分硬件功能由软件来实现,使得整个系统更易于测试、生产和维护升级。     

核电厂DCS系统功能验证工程模拟机研究

建立了核电厂分布式控制系统(DCS)功能验证工程模拟机系统.该系统采用RELAP5建立热工水力模型,利用MATLAB/Simulink建立电厂主要控制系统数学模型,利用MYSQL建立数据库,利用VisualStudio.NET开发了系统控制台;采用数据采集系统实现工程模拟机与现场DCS系统间的实时信号通讯,从而实现对DCS系统的功能验证.验证结果表明,系统能实现实时运行,并满足DCS系统硬件和逻辑功能测试的要求.     

核电厂蒸汽发生器的容错控制

基于考虑了随机噪声的蒸汽发生器非线性模型,利用一组扩展卡尔曼滤波器对传感器的状态进行监测,通过实时检测、分离单传感器故障并重构传感器的输出值,达到蒸汽发生器水位稳定的容错控制目的。结果表明,基于扩展卡尔曼滤波器组对蒸汽发生器进行容错控制设计的方法是可行的。     

基于BP神经网络的核电厂主动容错控制方法研究

针对核电厂中的传感器故障,采用改进的BP神经网络算法对传感器进行神经网络训练,建立各种运行状态下的动态模型库,并应用BP神经网络对系统进行实时检测。当传感器发生故障时,采用控制率重构的方法进行容错控制。在核动力装置模拟器上以稳压器为对象进行了仿真实验验证,结果表明该方法对于核电厂中的传感器故障进行容错控制是有效的。     

Fault Tolerant Memories for Single Particle Radiation Effects

Fault tolerant memory mechanizations are presented in this paper which combine standard Error Detection and Correction (EDAC) techniques with unique memory electrical/spacial organizations and computer protocols which account for single particle radiation effects and significantly reduce their impact on the memory system. The mechanizations also enhance reliability and increase survivability to macroscopic radiation effects including total dose failure and dose rate upset. Standard EDAC mechanizations allow the memory designer to reduce susceptibility to single particle soft upsets at the system level by orders of magnitude. The memory organization and computer protocols presented herein extend this susceptibility reduction to latchup and multiple soft or hard errors in a common word. The mechanizations are compatible with implementation on auxiliary LSI chip sets or partially in VHSIC RAM device structures themselves. They are also compatible with fault tolerant computer mechanizations which account for failure or upset of non RAM device logic circuitry (Processor and Memory).     

Reliability assessment of emergency exhaust system in a pool-type research reactor

The reliability of an extract system in a swimming-pool-type research reactor has been assessed. A global fault-tree analysis technique has been utilized. The basic event reliability data is based on both generic and reactor specific informations.The unavailability of the extract system is quantified in terms of the unavailability of the various functional requirements of the system. The unavailability is expressed as the probability of failure on demand. The computer system unavailability is determined from the minimal cutsets of the system. It is found that only three events have a major contribution to the top event, i.e., failures of compressed air supply, electric power supply and solenoid valve. A sensitivity analysis is performed to show the effects of variations in the data values of the dominant cutsets. An uncertainty analysis was also performed on the fault tree. The evaluations show that the reactor extract system lacks diversity and redundancy in most of its components. It is tolerant of most minor degradations, as these are taken care of by the operating policies and procedures. However, it can not tolerate common cause failures, e.g., simultaneous compressed air and electric power supply failure. Based upon the results obtained some recommendations are made.     

基于CFNN的核蒸汽发生器水位控制

鉴于常规的PID控制存在控制对象参数变化时控制参数无法改变的不足,从而根据一个核蒸汽发生器(NSG)的简化数学模型,将一种补偿模糊神经网络(CFNN)用于NSG水位的控制。该网络由于引入了补偿神经元,使网络的容错性更好,系统更稳定。同时在神经网络学习算法中动态优化补偿模糊运算,使网络更适应,训练速度更快。仿真表明,该方法在装置负荷变化时比常规的PID控制方法超调量小,收敛速度快。该网络能在线调整参数,动态优化模糊规则,适于在线学习控制。该控制方法对NSG水位智能控制研究具有一定意义。     

Development of SUPKIT-II: Computer Aided Fault Tree Analysis System

A computer aided reliability analysis system, in which an interactive graphic terminal can be used, to construct, modify, analyze, and store fault trees is developed. The system, SUPKIT-n, a computer aided fault tree analysis system has functions for fault tree automated construction (PREP) and fault tree graphics (GRAPH). The former automatically generates a fault tree by a hierachical structure based on system configuration and specifications, and/or from failure information, while the latter indicates, modifies, and evaluates the fault tree through CAD/CAM terminals. Therefore, PREP decreases man-hours and mistake occurrences in constructing fault trees and GRAPH enables users to evaluate system reliability and to compare system design plans easily and quickly.     

Adaptive fuzzy inference causal graph approach to fault detection and isolation of field devices in nuclear power plants

An adaptive fuzzy inference causal graph is presented as an integrated approach for fault detection and isolation of field devices including sensors, actuators, and controllers in nuclear power plants. In this approach, nuclear plant systems are represented as a causal graph consisting of individual process variables connected with adaptive fuzzy inference system models. The adaptive fuzzy inference system models generated from historical data are used to characterize the relationships among process variables during normal operation. Fault detection and isolation is achieved by monitoring and cause-effect reasoning on the residuals. This unique cause-effect reasoning strategy for fault isolation can avoid seeking signatures patterns from fault data, which are usually very difficult to obtain for a large system. The most parsimonious model structure, which is a decisive factor in building robust data driven models, is achieved through the system decomposition that inherent in a causal graph. The developed approach has been demonstrated for a simulated pressurized water reactor steam generator system. Both simple faults and complex faults with fault propagation can be successfully isolated during their incipient fault stages, regardless of fault magnitudes and initial power level.     

Fault detection and characterisation in Pressurised Water Reactors using real-time simulations

The use of real-time plant simulators running in parallel with a nuclear plant to predict the control system behaviour and highlighting unexpected plant behaviour is presented. The study is performed on a 910 MW Generation II Framatome Pressurised Water Reactor model and simulator. By simulating the plant behaviour in real-time whilst comparing it with the real-time transient the plant is following, a complete second set of expected control operations and simulated plant measurements is generated. This enables the calculation of the unknown set of variables introduced into the plant as a fault condition. The benefit of such a system is that plant faults that are too small to detect (especially during transients when the plant operating point is moving around) can be identified as unexpected or faulty plant behaviour. The behaviour of the control system is also continually predicted so the effect of the control system compensating for fault symptoms (which in most cases hides the fault condition) is used to characterise the fault as a control variable acting on the plant. The approach is illustrated by simulating a specific fault, small enough to go undetected for an extended period of time, during a typical transient. This is continually compared with a plant simulation, simulating the same transient without the fault. Using the described methodology, the fault is detected and characterised long before the plant safety is jeopardised or the fault is detected by the conventional protection system.     

Single event upsets for Space Shuttle flights of new generalpurpose computer memory devices

The replacement of the magnetic core with a well characterized semiconductor memory in the Space Shuttle orbiter general purpose computers (GPCs) has provided a wealth of on-orbit radiation effects data since 1991. The fault tolerant GPCs detect, correct, and downlink memory upset status and orbiter position information every few seconds, giving the ability to correlate 1400 upsets to date with altitude, geomagnetic latitude, and solar conditions. The predicted upset rate was computed by a modified path-length distribution method. The modification accounts for the Weibull distribution cross-section (rather than a single upset threshold) and the device sensitive volume thickness. Device thickness was estimated by the method normally used to account for edge effects at the upset cross-section discontinuity that occurs at ion changes. A Galactic cosmic ray environment model accurately models the average particle flux for each mission. The predicted and observed upset rates were found to be in good agreement for sensitive volume thicknesses consistent with the device's fabrication technology