核电厂大规模数字化仪控系统动态可靠性评价方法研究

Digital Instrumentation and Control System (DICS) is one of the critical systems of nuclear power plant (NPP) for safe operation. Operation maintenances and design improvement informed by results of DICS reliability assessment can improve safety of NPP. Failures of DICS have complex dynamic characteristics, so dynamic reliability assessment methodology should be adopted for better assessment results. As one of the most suitable methods, dynamic flowgraph methodology (DFM) can model adequately dynamic reliability characteristics of DICS, its deductive analysis can obtain all possible combinations of initial events which lead to a given system failure, thus it can locate weak links. NPP DICS is a large scale complex system, so DFM faces the challenges of heavy computational cost and significant modeling effort for DICS reliability assessment. To address the two shortcomings, DICS DFM efficient deductive analysis method and dynamic flowgraph modle intelligent construct approach are first proposed. The former is based on fast DFM deductive algorithm and importance degree and information entropy informed Mont Carlo sampling; The later first construct dynamic flowgraph modles liabrary for compenents of DICS, then employ topology and system configuration engineering file of DICS to automatically synthesize dynamic flowgraph of DICS.

数字化仪控系统(DICS, Digital Instrumentation and Control System)是确保核电厂安全运行的关键系统。准确评价DICS可靠性，进行有针对性的设计改进和运行维护，可有效提高核电厂安全水平。DICS失效具有复杂动态特性，为确保评价结果的准确度,应采用动态可靠性评价方法；作为最合适的动态评价方法之一，动态流图法能充分描述DICS的动态特性，其演绎分析能得到导致给定DICS失效的所有可能始发事件，定位薄弱环节。核电厂DICS为复杂大系统,应用动态流图法时，存在建模工作量巨大、演绎分析计算代价过高的缺点。针对上述不足，首次提出DICS 动态流图高效演绎方法和DICS 动态流图的智能构建方法。前者基于重要度和信息熵导向的蒙特卡洛抽样结合快速动态流图演绎算法实现；后者先建立DICS的组件动态流图模型库，再根据DICS的拓扑结构和系统配置，综合出DICS动态流图

数字化仪控系统(DICS)是确保核电厂安全运行的关键系统。准确评价DICS可靠性，进行有针对性的设计改进和运行维护，可有效提高核电厂安全水平。DICS失效具有复杂动态特性，为确保评价结果的准确度,应采用动态可靠性评价方法；作为最合适的动态评价方法之一，动态流图法（DFM）能充分描述DICS的动态特性，其演绎分析能得到导致给定DICS失效的所有可能始发事件，定位薄弱环节。DFM应用于核电厂DICS时，由于DICS为复杂大系统,，存在建模工作量巨大、演绎分析计算代价过高的缺点。针对现有DFM演绎分析计算代价过高的不足，提出了DFM快速演绎方法。针对基准题的对比计算表明，所提快速演绎方法在多步回溯演绎分析时，计算效率是Dymonda方法的10倍以上。针对现有现有DFM建模系统化、自动化程度较低的情况，基于系统工程论和面向对象理念，提出了一种面向对象DFM建模平台。该平台根据DICS设备的冗余性和标准化特性，开发DICS各类设备对应的转移/转换门图元库，并利用这些图元，建立DICS机架和机柜的组件级DFM子模型库，并存于建模平台中供重复使用，提高了建模的效率和模型的可读性。项目还对两个DICS子系统建立故障树模型和布尔逻辑驱动马尔科夫过程模型，以便验证和确认所提方法和所开发平台的有效性。