核安全级DCS软件可靠性评估方法研究

Methodology Study on Safety-Critical Software Reliability Evaluation of Digital I&C Systems at Nuclear Power Plants

在对核安全级数字化仪控系统(DCS)软件可靠性评估方法进行比较分析的基础上,以AP1000压水堆核电厂为例,采用NUREG-0800《核电站安全审查大纲技术》中的技术分支BTP7-14作为参考标准,利用贝叶斯网络方法构建反应堆保护系统可靠性评估模型,并设定评估模型指标之间的依存度。用所构建的软件可靠性评估模型进行软件可靠性定量评估,进一步通过敏感度分析对评估模型的关键性指标和指标的细化程度进行判别,可获得软件可靠性改进的方向。

Based on the comparative analysis of the current DCS sot^ware evaluation methods, the authors adopted the BTP7-14 of NUREG-0800 as the reference standard for evaluating AP 1000 nuclear power plants. An overall framework based on Bayesian Belief Network （BBN） for reactor protection system software reliability evaluation was therefore presented. The dependency between evaluation model criteria was decided. A quantitative evaluation was performed based on the sotiware evaluation model. Furthermore, a sensitivity analysis method is proposed for identifying the key criteria and the refinement degree of each criterion which will be helpful to make clear the direction of the software quality improvement.