基于左右模糊排序法的海上浮动核电站设备可靠性评估

Reliability analysis and evaluation of the key equipment of the marine floating nuclear power plants based on the left-right fuzzy ranking

为了评估海上浮动核电站设备的可靠性,通过专家评价对设备的失效情况进行分析,改进岭形隶属度函数,使用左右模糊排序法将模糊数转化为模糊概率,从而建立了海上浮动核电站设备失效概率模型。以海上浮动核电站冷却剂泵和非能动余热排出系统为算例验证模型的有效性,结果表明,提出的方法适用于海上浮动核电站设备可靠性评估,可为海上浮动核电站安全分析提供理论基础。

Aiming to solve the problem ofthe data reliability of the marine floating nuclear power plants,this paper presents a method based on the fuzzy theory to determine the failure probability of the components of such marine floating nuclear power plants.As is known,since the system structure and the operating environment of marine floating nuclear power plants are to be quite different from those of the land-on reactors,the failure rates of the same components ought to be made much lower with a lot of difference.That is why,first of all,it is necessary to analyzethe failure indexes of the equipment concerned by the expert evaluation,and then to make them adapted to the multi-level evaluation technical terms,so as to improve the ridge membership functions.And,in doing so,we have also managed to transform the expert evaluation results into the fuzzy probability expressions by the so-called left-right fuzzy ranking so as to establish a failure probability model of the floating nuclear power plant device and equipment items.In order to verify the validity of the model,we have also analyzed the coolant pumps and the passive residual heat removal systems of the power plant as the sampling cases.And,then,we have established an expert evaluation team made of different professionals to evaluate the typical failure modes of its coolant pump and passive residual heat removal system,and,then,to convert the evaluation results into the failure probability assessment data by using our self-established failure probability model.As shown in the calculation results,the reliability of the floating nuclear power plants have now been proven below the needed technical standard levels as required by the land nuclear power plant for the same components.The main reason for the failure to achieve the needed standard technical indexes is the failure to take into enough account of the vibration,the sway,the seawater corrosion and some other indicators in the actual conditions of the floating nuclear power plants,though the calculation results can be said basically come to the safety demands of the said components through a comparison with the reliability data of the land-on reactors.Thus,the evaluation method we have adopted to the offshore floating nuclear power plants here is good enough to serve as a theoretical basis for the future safety analysis of such offshore floating nuclear power plant systems in a form of accident trees of quantitative and qualitative calculation indexes.